U.S. patent application number 17/634921 was filed with the patent office on 2022-09-15 for separating device and use of a separating device.
The applicant listed for this patent is 3M INNOVATIVE PROPERTIES COMPANY. Invention is credited to Frank A. Meschke, George P. Victor.
Application Number | 20220290531 17/634921 |
Document ID | / |
Family ID | 1000006432138 |
Filed Date | 2022-09-15 |
United States Patent
Application |
20220290531 |
Kind Code |
A1 |
Victor; George P. ; et
al. |
September 15, 2022 |
SEPARATING DEVICE AND USE OF A SEPARATING DEVICE
Abstract
The present disclosure relates to a separating device for
removing solid particles from fluids, and to the use of said
separating device for removing solid particles from fluids.
Inventors: |
Victor; George P.;
(Wiggensbach, DE) ; Meschke; Frank A.;
(Buchenberg, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
3M INNOVATIVE PROPERTIES COMPANY |
St. Paul |
MN |
US |
|
|
Family ID: |
1000006432138 |
Appl. No.: |
17/634921 |
Filed: |
August 12, 2020 |
PCT Filed: |
August 12, 2020 |
PCT NO: |
PCT/IB2020/057594 |
371 Date: |
February 11, 2022 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
E21B 43/086
20130101 |
International
Class: |
E21B 43/08 20060101
E21B043/08 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 14, 2019 |
EP |
19191660.0 |
Claims
1. A separating device for removing solid particles from fluids,
comprising: a stack of at least three annular discs defining a
central annular region along a central axis, each annular disc
having an upper side and an underside, wherein the upper side of
each annular disc each has two or more spacers, and wherein the
spacers of the upper side of each annular disc contact the
underside of the adjacent annular disc, and wherein the annular
discs are stacked in such a way that a separating gap for the
removal of solid particles is present in each case between adjacent
annular discs, and wherein the central annular region comprises a
first section and a second section, a supporting structure for
axial bracing of the central annular region, wherein the supporting
structure is located inside the central annular region, a tubular
shroud for protection of the central annular region from mechanical
damage, and an intermediate element which is placed between the
first section and the second section of the central annular region,
wherein the intermediate element supports the shroud, and wherein
each annular disc comprises a material independently selected from
the group consisting of (i) ceramic materials; (ii) mixed materials
having fractions of ceramic or metallic hard materials and a
metallic binding phase; and (iii) powder metallurgical materials
with hard material phases formed in-situ, wherein the intermediate
element comprises a material selected from the group consisting of
(i) ceramic materials; (ii) mixed materials having fractions of
ceramic or metallic hard materials and a metallic binding phase;
and (iii) powder metallurgical materials with hard material phases
formed in-situ, wherein the intermediate element comprises an
intermediate core element and a protective bush which is co-centric
with and located outside of the intermediate core element, and
wherein the protective bush protects the intermediate core element
from mechanical damage, and wherein the intermediate core element
comprises a material selected from the group consisting of (i)
ceramic materials; (ii) mixed materials having fractions of ceramic
or metallic hard materials and a metallic binding phase; and (iii)
powder metallurgical materials with hard material phases formed
in-situ, and wherein the protective bush comprises a metallic
material or a polymeric material.
2. A separating device for removing solid particles from fluids,
comprising: a stack of at least three annular discs defining a
central annular region along a central axis, each annular disc
having an upper side and an underside, wherein the upper side and
the underside of every second annular disc in the stack each has
two or more spacers, and wherein the upper side and the underside
of the respectively adjacent annular discs do not comprise any
spacers, and wherein the spacers of the upper side of every second
annular disc in the stack contact the underside of the adjacent
annular disc, and wherein the spacers of the underside of every
second annular disc in the stack contact the upper side of the
adjacent annular disc, and wherein the annular discs are stacked in
such a way that a separating gap for the removal of solid particles
is present in each case between adjacent annular discs, and wherein
the central annular region comprises a first section and a second
section, a supporting structure for axial bracing of the central
annular region, wherein the supporting structure is located inside
the central annular region, a tubular shroud for protection of the
central annular region from mechanical damage, and an intermediate
element which is placed between the first section and the second
section of the central annular region, wherein the intermediate
element supports the shroud, and wherein each annular disc
comprises a material independently selected from the group
consisting of (i) ceramic materials; (ii) mixed materials having
fractions of ceramic or metallic hard materials and a metallic
binding phase; and (iii) powder metallurgical materials with hard
material phases formed in-situ, wherein the intermediate element
comprises a material selected from the group consisting of (i)
ceramic materials; (ii) mixed materials having fractions of ceramic
or metallic hard materials and a metallic binding phase; and (iii)
powder metallurgical materials with hard material phases formed
in-situ, wherein the intermediate element comprises an intermediate
core element and a protective bush which is co-centric with and
located outside of the intermediate core element, and wherein the
protective bush protects the intermediate core element from
mechanical damage, and wherein the intermediate core element
comprises a material selected from the group consisting of (i)
ceramic materials; (ii) mixed materials having fractions of ceramic
or metallic hard materials and a metallic binding phase; and (iii)
powder metallurgical materials with hard material phases formed
in-situ, and wherein the protective bush comprises a metallic
material or a polymeric material.
3. The separating device according to claim 1, wherein the
supporting structure for axial bracing of the central annular
region comprises one or more rods arranged within the central
annular region.
4. The separating device according to claim 1, wherein the
supporting structure for axial bracing of the central annular
region comprises a perforated pipe which is co-centric with and
located inside the central annular region, and an end cap at the
upper end and an end cap at the lower end of the central annular
region, the end cap being co-centric with the perforated pipe and
being firmly connected to the perforated pipe, and wherein the
intermediate element is co-centric with the perforated pipe.
5. The separating device according to claim 1, wherein the outer
diameter of the intermediate element is larger than the outer
diameter of the central annular region.
6. The separating device according to claim 1, wherein the
protective bush is firmly connected to the intermediate core
element.
7. The separating device of claim 4, wherein the separating device
further comprises one or more bands which are provided on the
lateral surface of the perforated pipe and which are inside the
central annular region and inside the intermediate element, and
wherein the annular discs are centered by the one or more bands on
the perforated pipe.
8. The separating device according to claim 1, wherein the
intermediate element is movable in axial direction.
9. The separating device according to claim 1, wherein the
intermediate element further comprises an annular element which is
co-centric with the intermediate core element and which is located
inside the intermediate core element.
10. The separating device according to claim 7, wherein the
intermediate element further comprises an annular element which is
co-centric with the intermediate core element and which is located
inside the intermediate core element and between the intermediate
core element and the perforated pipe, and wherein the annular
element is provided with one or more recesses in axial direction
distributed along the circumference of the annular element, and
wherein the number of recesses is equal to or larger than the
number of bands which are provided on the lateral surface of the
perforated pipe, and wherein each of the bands is placed in one of
the recesses of the annular element.
11. The separating device according to claim 9, wherein the annular
element is firmly connected to the intermediate core element.
12. The separating device of claim 1, wherein the separating device
further comprises a number of n further intermediate elements,
wherein n is an integer from 1 to 10, and wherein the central
annular region further comprises a number of n further sections,
and wherein each further intermediate element is placed between two
adjacent sections of the central annular region.
13. (canceled)
14. The separating device according to claim 2, wherein the
supporting structure for axial bracing of the central annular
region comprises one or more rods arranged within the central
annular region.
15. The separating device according to claim 2, wherein the
supporting structure for axial bracing of the central annular
region comprises a perforated pipe which is co-centric with and
located inside the central annular region, and an end cap at the
upper end and an end cap at the lower end of the central annular
region, the end cap being co-centric with the perforated pipe and
being firmly connected to the perforated pipe, and wherein the
intermediate element is co-centric with the perforated pipe.
16. The separating device of claim 15, wherein the separating
device further comprises one or more bands which are provided on
the lateral surface of the perforated pipe and which are inside the
central annular region and inside the intermediate element, and
wherein the annular discs are centered by the one or more bands on
the perforated pipe.
17. The separating device according to claim 16, wherein the
intermediate element further comprises an annular element which is
co-centric with the intermediate core element and which is located
inside the intermediate core element and between the intermediate
core element and the perforated pipe, and wherein the annular
element is provided with one or more recesses in axial direction
distributed along the circumference of the annular element, and
wherein the number of recesses is equal to or larger than the
number of bands which are provided on the lateral surface of the
perforated pipe, and wherein each of the bands is placed in one of
the recesses of the annular element.
18. The separating device according to claim 2, wherein the
intermediate element is movable in axial direction.
19. The separating device according to claim 2, wherein the
intermediate element further comprises an annular element which is
co-centric with the intermediate core element and which is located
inside the intermediate core element.
20. The separating device of claim 2, wherein the separating device
further comprises a number of n further intermediate elements,
wherein n is an integer from 1 to 10, and wherein the central
annular region further comprises a number of n further sections,
and wherein each further intermediate element is placed between two
adjacent sections of the central annular region.
Description
TECHNICAL FIELD
[0001] The present disclosure relates to a separating device for
the removal of solid particles from a fluid.
BACKGROUND
[0002] Separating devices for the removal of solid particles from a
fluid are required in many oil and gas extraction wells. Mineral
oil and natural gas are stored in naturally occurring underground
reservoirs, the oil or gas being distributed in more or less porous
and permeable mineral layers. The aim of every oil or gas drill
hole is to reach the reservoir and exploit it in such a way that,
as far as possible, only saleable products such as oil and gas are
extracted, while undesired by-products are minimized or even
avoided completely. The undesired by-products in oil and gas
extraction include solid particles such as sands and other mineral
particles that are entrained from the reservoir up to the borehole
by the liquid or gas flow.
[0003] Since the mineral sands are often abrasive, the influx of
such solids into the production tubing and pump cause considerable
undesired abrasive and erosive wear on all of the technical
internals of the borehole. It is therefore endeavoured to free the
production flow of undesired sands directly after it leaves the
reservoir, that is to say while it is still in the borehole, by
filter systems.
[0004] Problems of abrasion and erosion in the removal of solid
particles from liquid and gas flows are not confined to the oil and
gas industry, but may also occur in the extraction of water. Water
may be extracted for the purpose of obtaining drinking water or
else for the obtainment of geothermal energy. The porous, often
loosely layered reservoirs of water have the tendency to introduce
a considerable amount of abrasive particles into the material that
is extracted. In these applications too, there is the need for
abrasion- and erosion-resistant filters. Also in the extraction of
ore and many other minerals, there are problems of abrasion and
erosion in the removal of solid particles from liquid and gas
flows.
[0005] In oil and gas extraction, the separation of undesired
particles is usually achieved today by using filters that are
produced by spirally winding and welding steel forming wires onto a
perforated basepipe. Such filters are referred to as "wire wrap
filters". Another commonly used type of construction for filters in
oil and gas extraction is that of wrapping a perforated basepipe
with metal screening meshes. These filters are referred to as
"metal mesh screens". Both methods provide filters with effective
screen apertures of 75 .mu.m to 350 .mu.m. Depending on the type of
construction and the planned intended use of both these types of
filter, the filtering elements are additionally protected from
mechanical damage during transport and introduction into the
borehole by an externally fitted, coarse-mesh cage. The
disadvantage of these types of filter is that, under the effect of
the abrasive particles flowing at high speed, metal structures are
subject to rapid abrasive wear, which quickly leads to destruction
of the filigree screen structures. Such high-speed abrasive flows
often occur in oil and/or gas extraction wells, which leads to
considerable technical and financial maintenance expenditure
involved in changing the filters. There are even extraction wells
which, for reasons of these flows, cannot be controlled by the
conventional filtering technique, and therefore cannot be
commercially exploited. Conventional metallic filters are subject
to abrasive and erosive wear, since steels, even if they are
hardened, are softer than the particles in the extraction wells,
which sometimes contain quartz.
[0006] In order to counter the abrasive flows of sand with
abrasion-resistant screen structures, U.S. Pat. No. 8,893,781 B2,
U.S. Pat. No. 8,833,447 B2, U.S. Pat. No. 8,662,167 B2 and
WO 2016/018821 A1 propose filter structures in which the filter
gaps, that is to say the functional openings of the filter, are
created by stacking specially formed densely sintered annular discs
of a brittle-hard material, preferably of a ceramic material. In
this case, spacers are arranged on the upper side of annular discs,
distributed over the circumference of the discs.
[0007] In the separating device of WO 2016/018821 A1, a perforated
pipe is located inside the stack of annular discs, onto which pipe
the brittle-hard annular discs are stacked. At the upper and lower
end of the separating device, there are end caps made of steel
which are firmly connected to the perforated pipe. Usually,
separating devices such as disclosed in WO 2016/018821 A1 consist
of an arrangement of separate modules, each module comprising a
stack of brittle-hard annular discs. The modules are connected via
intermediate elements made of steel. The intermediate elements are
firmly connected with the perforated pipe. The intermediate
elements are housing a compensator system which is usually made
from steel, e.g. provided as springs, and which is required to
compensate the thermal mismatch of perforated pipe and the stack of
annular discs. Under operating conditions, the intermediate parts
and also the compensator system are exposed to erosive and
corrosive environment which is a risk for damage. The intermediate
element and also the compensator system made from steel may erode
and may get damaged to an extent where it loses its function,
resulting in loss of sand control, and production has to be
stopped.
[0008] Therefore, there is still a need to provide an improved
separating device for the removal of solid particles from fluids,
in particular from oil, gas and water. Particularly, there is a
need to provide a separating device having an improved erosion and
corrosion resistance.
[0009] As used herein, "a", "an", "the", "at least one" and "one or
more" are used interchangeably. The term "comprise" shall include
also the terms "consist essentially of" and "consists of".
SUMMARY
[0010] In a first aspect, the present disclosure relates to a
separating device for removing solid particles from fluids,
comprising
[0011] a stack of at least three annular discs defining a central
annular region along a central axis, each annular disc having an
upper side and an underside, wherein the upper side of each annular
disc each has two or more spacers, and wherein the spacers of the
upper side of each annular disc contact the underside of the
adjacent annular disc, and wherein the annular discs are stacked in
such a way that a separating gap for the removal of solid particles
is present in each case between adjacent annular discs, and wherein
the central annular region comprises a first section and a second
section,
[0012] a supporting structure for axial bracing of the central
annular region, wherein the supporting structure is located inside
the central annular region,
[0013] a tubular shroud for protection of the central annular
region from mechanical damage, and
[0014] an intermediate element which is placed between the first
section and the second section of the central annular region,
wherein the intermediate element supports the shroud,
[0015] and wherein each annular disc comprises a material
independently selected from the group consisting of (i) ceramic
materials; (ii) mixed materials having fractions of ceramic or
metallic hard materials and a metallic binding phase; and (iii)
powder metallurgical materials with hard material phases formed
in-situ,
[0016] and wherein the intermediate element comprises a material
selected from the group consisting of (i) ceramic materials; (ii)
mixed materials having fractions of ceramic or metallic hard
materials and a metallic binding phase; and (iii) powder
metallurgical materials with hard material phases formed
in-situ.
[0017] In another aspect, the present disclosure also relates to a
separating device for removing solid particles from fluids,
comprising
[0018] a stack of at least three annular discs defining a central
annular region along a central axis, each annular disc having an
upper side and an underside, wherein the upper side and the
underside of every second annular disc in the stack each has two or
more spacers, and wherein the upper side and the underside of the
respectively adjacent annular discs do not comprise any spacers,
and wherein the spacers of the upper side of every second annular
disc in the stack contact the underside of the adjacent annular
disc, and wherein the spacers of the underside of every second
annular disc in the stack contact the upper side of the adjacent
annular disc, and wherein the annular discs are stacked in such a
way that a separating gap for the removal of solid particles is
present in each case between adjacent annular discs, and wherein
the central annular region comprises a first section and a second
section,
[0019] a supporting structure for axial bracing of the central
annular region, wherein the supporting structure is located inside
the central annular region,
[0020] a tubular shroud for protection of the central annular
region from mechanical damage, and
[0021] an intermediate element which is placed between the first
section and the second section of the central annular region,
wherein the intermediate element supports the shroud,
[0022] and wherein each annular disc comprises a material
independently selected from the group consisting of (i) ceramic
materials; (ii) mixed materials having fractions of ceramic or
metallic hard materials and a metallic binding phase; and (iii)
powder metallurgical materials with hard material phases formed
in-situ,
[0023] and wherein the intermediate element comprises a material
selected from the group consisting of (i) ceramic materials; (ii)
mixed materials having fractions of ceramic or metallic hard
materials and a metallic binding phase; and (iii) powder
metallurgical materials with hard material phases formed
in-situ.
[0024] In yet a further aspect, the present disclosure relates to
the use of a separating device as disclosed herein for removing
solid particles from fluids
[0025] in a process for extracting fluids from extraction wells,
or
[0026] in water or in storage installations for fluids, or
[0027] in a process for extracting ores and minerals.
[0028] The separating device as disclosed herein has an improved
erosion resistance. The separating device as disclosed herein also
has an improved corrosion resistance to the media to be extracted
and the media used for maintenance such as acids. More
specifically, the intermediate element of the separating device as
disclosed herein has an improved erosion resistance and an improved
corrosion resistance to the media to be extracted and the media
used for maintenance such as acids.
[0029] The intermediate element of the separating device as
disclosed herein is shorter than the intermediate element of the
prior art. Depending on the diameter of the stack of annular discs,
the length of the intermediate element is only from 25 to 50% of
the length of an intermediate element of the prior art. Therefore,
the filter area can be increased by adding more annular discs on
the same length of a perforated pipe.
[0030] The separating device as disclosed herein can be used for
harsh environments, that is for reservoirs to be exploited with
streaks having high inflow and high erosional impact.
[0031] The intermediate element of the separating device as
disclosed herein does not house a compensator system for
compensating the thermal mismatch of perforated pipe and central
annular region.
BRIEF DESCRIPTION OF THE DRAWINGS
[0032] The present disclosure is explained in more detail on the
basis of the drawings, in which
[0033] FIG. 1A schematically shows the overall view of a separating
device as disclosed herein;
[0034] FIG. 1B shows a cross-sectional view of a separating device
as disclosed herein;
[0035] FIGS. 1C and 1D show details of the cross-sectional view of
FIG. 1B;
[0036] FIGS. 2A-2F show various details of the intermediate element
of a separating device as disclosed herein;
[0037] FIGS. 3A-3L show various details of the stack of annular
discs of a separating device as disclosed herein; and
[0038] FIGS. 4A-4L show various details of the stack of annular
discs of a separating device as disclosed herein.
DETAILED DESCRIPTION
[0039] Preferred embodiments and details of the separating device
of the present disclosure are explained in more detail below with
reference to the drawings.
[0040] FIG. 1A shows the overall view of a separating device
according to the present disclosure. FIG. 1B shows a
cross-sectional view of a separating device according to the
present disclosure. The separating device according to the present
disclosure comprises a stack of at least three annular discs
defining a central annular region 1, 13 along a central axis. The
separating device comprises a supporting structure for axial
bracing of the central annular region. The supporting structure is
located inside the central annular region 1, 13. The supporting
structure may comprise a perforated pipe 7, on which the annular
discs are stacked. The perforated pipe 7 with perforations 23 is
located inside the stack 1, 13 of annular discs and is also
referred to hereinafter as the base pipe. In other embodiments
which are not shown in the drawings, the supporting structure of
the separating device comprises one or more rods arranged within
the central annular region.
[0041] Usually provided at both ends of the perforated pipe 7 are
threads 24, by way of which the separating device can be connected
to further components, either to further separating devices or to
further components of the extraction equipment. For connection to
further components, a coupling 30 with inner threads on both sides
may be screwed onto the thread 24.
[0042] If the supporting structure of the separating device
comprises a perforated pipe, the supporting structure further
comprises an end cap 8 at the upper end of the central annular
region and an end cap 9 at the lower end of the central annular
region 1, 13, the end caps being firmly connected to the base pipe
7.
[0043] The separating device further comprises a tubular shroud 22
(see FIG. 1A) for protection of the central annular region 1, 13
from mechanical damage. The shroud 22 can be freely passed through
by a flow. The shroud 22 protects the central annular region from
mechanical damage during handling and fitting into the
borehole.
[0044] For better understanding, and since the separating device
according to the present disclosure is generally introduced into an
extraction borehole in vertical alignment, the terms "upper" and
"lower" are used here, but the separating device may also be
positioned in horizontal orientation in the extraction borehole (in
which case, upper typically would refer to the most upstream
portion and lower would refer to the most downstream portion of the
separating device, when in service).
[0045] The separating device according to the present disclosure
comprises a stack of at least three annular discs defining a
central annular region 1, 13 (see FIGS. 1B, 3H, 4H) along a central
axis. The annular discs 2, 14, 15 (see FIGS. 3A-3F and 4A-4J) have
an upper side 3, 16, 18 and an underside 4, 17, 19 (see FIGS. 3B,
4B, 4I-4J).
[0046] In some embodiments, the upper side 3 of each annular disc 2
of the central annular region 1 each has two or more spacers 5 (see
FIG. 3A), and the underside 4 of each annular disc does not
comprise any spacers (see FIG. 3B). The spacers 5 of the upper side
3 of each annular disc 2 contact the underside 4 of the adjacent
annular disc. The annular discs 2 are stacked in such a way that a
separating gap 6 for the removal of solid particles is present in
each case between adjacent annular discs (see FIGS. 3H-3J).
[0047] The contact area 25 of the spacers 5 may be planar, so that
the spacers 5 have a planar contact area with the adjacent annular
disc (see FIGS. 3C and 3E). The planar contact area 25 is in
contact with the adjacent underside 4 of the adjacent annular
disc.
[0048] The upper side 3 of each annular disc 2 may have only two
spacers 5. Typically, the upper side 3 of each annular disc 2 has
three or more spacers 5 which are distributed over the
circumference of the upper side 3 of the annular discs 2.
[0049] The underside 4 of each annular disc 2 may be formed at
right angles to the central axis.
[0050] Each annular disc 2 comprises a material independently
selected from the group consisting of (i) ceramic materials; (ii)
mixed materials having fractions of ceramic or metallic hard
materials and a metallic binding phase; and (iii) powder
metallurgical materials with hard material phases formed
in-situ.
[0051] In some further embodiments, the upper side 16 and the
underside 17 of every second annular disc 14 of the central annular
region 13 each has two or more spacers 5 (see FIGS. 4A-4F). The
upper side 18 and the underside 19 of the respectively adjacent
annular discs 15 do not comprise any spacers (see FIGS. 4H-4J). The
spacers 5 of the upper side 16 of every second annular disc 14 in
the stack contact the underside 19 of the adjacent annular disc 15,
and the spacers 5 of the underside 17 of every second annular disc
14 in the stack contact the upper side 18 of the adjacent annular
disc 15. The annular discs are stacked in such a way that a
separating gap 6 for the removal of solid particles is present in
each case between adjacent annular discs (see FIGS. 4H-4J).
[0052] The upper side 16 and the underside 17 of each annular disc
14 each may have only two spacers 5. Typically, the upper side 16
and the underside 17 of each annular disc 14 each has three or more
spacers 5 which are distributed over the circumference of the upper
side 16 and the underside 17 of the annular discs 14.
[0053] The contact area 25 of the spacers 5 may be planar, so that
the spacers 5 have a planar contact area with the adjacent annular
disc (see FIGS. 4C, 4E). The planar contact area 25 of the spacers
5 of the upper side 16 of an annular disc 14 is in contact with the
underside 19 of the adjacent annular disc 15, and the planar
contact area 25 of the spacers 5 of the underside 17 of an annular
disc 14 is in contact with the upper side 18 of the adjacent
annular disc 15.
[0054] Every upper side 18 of an annular disc 15 which does not
comprise any spacers may be formed at right angles to the central
axis, and every underside 19 of an annular disc 15 which does not
comprise any spacers may be formed at right angles to the central
axis.
[0055] Each annular disc 14, 15 comprises a material independently
selected from the group consisting of (i) ceramic materials; (ii)
mixed materials having fractions of ceramic or metallic hard
materials and a metallic binding phase; and (iii) powder
metallurgical materials with hard material phases formed
in-situ.
[0056] The separating device as disclosed herein may comprise a
supporting structure comprising a perforated pipe 7 located in the
central annular region 1, 13 (see FIGS. 1A-1C) and two end caps 8,
9 (see FIGS. 1A and 1B) at the upper and lower ends of the central
annular region 1, 13.
[0057] The perforated pipe or base pipe is co-centric with the
central annular region. The base pipe is perforated, i.e. provided
with holes, in the region of the central annular region; it is not
perforated outside the region of the central annular region. The
perforation 23 serves the purpose of directing the filtered fluid,
i.e. the fluid flow freed of the solid particles, such as for
example gas, oil or mixtures thereof, into the interior of the base
pipe, from where it can be transported or pumped away.
[0058] Threads 24 are usually cut at both ends of the base pipe 7
and can be used for screwing the base pipes together into long
strings, for example with a coupling 30.
[0059] The base pipe can consist of a metallic material, a polymer
or ceramic material. The base pipe may consist of a metallic
material such as steel, for example steel L80. Steel L80 refers to
steel that has a yield strength of 80 000 psi (corresponding to
about 550 MPa). As an alternative to steel L80, steels that are
referred to in the oil and gas industry as J55, N80, C90, T95, P110
and L80Cr13 (see Drilling Data Handbook, 8th Edition, IFP
Publications, Editions Technip, Paris, France) may also be used.
Other steels, in particular corrosion-resistant alloy and
high-alloy steels, may also be used as the material for the base
pipe. For special applications in corrosive conditions, base pipes
of nickel-based alloys or Duplex stainless steels may also be used.
It is also possible to use aluminum materials as the material for
the base pipe, in order to save weight. Furthermore, base pipes of
titanium or titanium alloys may also be used.
[0060] The inside diameter of the annular discs must be greater
than the outside diameter of the base pipe. This is necessary on
account of the differences with regard to the thermal expansion
between the metallic base pipe and the material from which the
annular discs are made and also for technical reasons relating to
flow. It has been found to be favorable in this respect that the
inside diameter of the annular discs is at least 0.5 mm and at most
10 mm greater than the outside diameter of the base pipe. In
particular embodiments, the inside diameter of the annular discs is
at least 1.5 mm and at most 5 mm greater than the outside diameter
of the base pipe.
[0061] The outside diameter of the base pipe is typically from 2.54
cm to 25.4 cm (1 inch to 10 inches).
[0062] The end caps are produced from metal, usually steel and
typically from the same material as the base pipe. The end caps 8,
9 may be firmly connected to the base pipe 7. The end caps may be
fastened to the base pipe by means of welding, clamping, riveting
or screwing. During assembly, the end caps are pushed onto the base
pipe after the central annular region and are subsequently fastened
on the base pipe. In the embodiment of the separating device as
disclosed herein that is shown in FIGS. 1A-1D, the end caps are
fastened by means of welding.
[0063] The central annular region 1, 13 of the separating device as
disclosed herein comprises a first section 11 and a second section
12.
[0064] The separating device as disclosed herein further comprises
an intermediate element 10 which is placed between the first
section 11 and the second section 12 of the central annular region
1, 13. For embodiments of the separating device with the supporting
structure comprising a perforated pipe, the intermediate element 10
is co-centric with the perforated pipe 7. The intermediate element
10 supports the shroud 22.
[0065] Of course, as described herein, "co-centric", "planar",
"plane-parallel" and "at right angles" (and similar terms) mean
substantially so, within, for instance, relevant manufacturing,
assembly and/or operational tolerances.
[0066] The upper side of the intermediate element 10 in axial
direction contacts the underside of the last annular disc at the
lower end of the first section 11 of the central annular region 1,
13. The underside of the intermediate element 10 in axial direction
contacts the upper side of the first annular disc at the upper end
of the second section 12 of the central annular region 1, 13.
[0067] The intermediate element 10 comprises a material selected
from the group consisting of (i) ceramic materials; (ii) mixed
materials having fractions of ceramic or metallic hard materials
and a metallic binding phase; and (iii) powder metallurgical
materials with hard material phases formed in-situ. In some
embodiments, the intermediate element 10 is made from a material
selected from the group consisting of (i) ceramic materials; (ii)
mixed materials having fractions of ceramic or metallic hard
materials and a metallic binding phase; and (iii) powder
metallurgical materials with hard material phases formed
in-situ.
[0068] These materials are erosion resistant to abrasive fluid
flows and also corrosion resistant to the media to be extracted and
the media used for maintenance such as acids.
[0069] The outer diameter of the intermediate element 10 is larger
than the outer diameter of the central annular region 1, 13. The
outer diameter of the intermediate element 10 is larger than the
outer diameter of the first section 11 and of the second section 12
of the central annular region 1, 13. The intermediate element 10
being supported by the shroud 22 and having an outer diameter being
larger than the outer diameter of the central annular region
ensures that there is a distance between the shroud 22 and the
central annular region 1, 13 during deployment of the separating
device, and also in case of bending if the separating device needs
to be introduced in curved boreholes.
[0070] In some embodiments of the separating device as disclosed
herein, the intermediate element 10 comprises an intermediate core
element 26 and a protective bush 20 which is co-centric with the
intermediate core element 26.
[0071] The intermediate core element 26 comprises a material
selected from the group consisting of (i) ceramic materials; (ii)
mixed materials having fractions of ceramic or metallic hard
materials and a metallic binding phase; and (iii) powder
metallurgical materials with hard material phases formed in-situ.
In some embodiments, the intermediate core element 26 is made from
a material selected from the group consisting of (i) ceramic
materials; (ii) mixed materials having fractions of ceramic or
metallic hard materials and a metallic binding phase; and (iii)
powder metallurgical materials with hard material phases formed
in-situ.
[0072] The protective bush 20 protects the intermediate core
element 26 from mechanical damage. Mechanical damage of the
intermediate element may occur during installation of the
separating device in the borehole.
[0073] The protective bush 20 may comprise a metallic material or a
polymeric material. The protective bush 20 may be made from a
metallic material or from a polymeric material. The metallic
material of the protective bush may be steel. The polymeric
material of the protective bush may be, for example,
polytetrafluoroethylene (PTFE) or a polyaramide such as
poly(p-phenylene terephthalamide) (PPTA; trade names: Kevlar,
Twaron).
[0074] The protective bush 20 is located outside of the
intermediate core element 26 (see FIGS. 1C, 2E, 2F).
[0075] If the protective bush 20 is eroded by the abrasive fluid
flows under operating conditions of the separating device, the
intermediate core element 26 of the intermediate element 10 ensures
that the intermediate element 10 remains erosion and corrosion
resistant during the whole service life of the separating
device.
[0076] In some embodiments of the separating device as disclosed
herein, the protective bush 20 is firmly connected to the
intermediate core element 26. For example, if the protective bush
is made from a metallic material, the protective bush 20 may be
shrunk onto the intermediate core element 26. In some other
embodiments, the protective bush 20 may also be only pushed on the
intermediate core element 26 and may be not firmly connected to the
intermediate core element 26.
[0077] The outer diameter of the protective bush 20 is larger than
the outer diameter of the central annular region 1, 13. The outer
diameter of the protective bush 20 is smaller than the inner
diameter of the shroud 22 at the position of the intermediate
element 10. The inner diameter of the protective bush 20 may be
larger or smaller than or equal to the outer diameter of the first
and second section 11, 12 of the central annular region 1, 13.
Preferably, the inner diameter of the protective bush 20 is equal
to or larger than the diameter of the circle circumscribed around
the planar contact areas 25 of the spacers 5 of the annular discs
2, 14, so that the complete planar contact areas 25 of the spacers
5 have planar contact with the intermediate core element 26. The
inner diameter of the protective bush 20 may also be smaller, in
this case an annular disc having a rectangular cross-sectional area
and no spacers is placed next to the upper and lower end of the
intermediate element 10. The area of the upper side and underside
of this annular disc having a rectangular cross-sectional area and
no spacers may be at least as large as the sum of the planar
contact areas 25 of all spacers 5 of the adjacent annular disc 2,
14.
[0078] The outer lateral surface of the protective bush 20 may be
cylindrical. It is also possible that the cross-sectional area of
the protective bush in axial direction is T-shaped and the outer
lateral surface of the protective bush 20 has a recess at the upper
axial end and a recess at the lower axial end of the protective
bush. These recesses accommodate the shroud 22 for the first and
second section 11, 12 of the central annular region 1, 13. In this
case, the outer diameter of the protective bush is the largest
outer diameter of the protective bush at the central position.
[0079] FIG. 1C shows a detail of FIG. 1B at the position of the
intermediate element 10. The intermediate element 10 is placed
between the first section 11 and the second section 12 of the
central annular region 1, 13. The intermediate element 10 is
co-centric with the perforated pipe 7. The outer diameter of the
intermediate element 10 is larger than the outer diameter of the
central annular region 1, 13. The outer diameter of the
intermediate element 10 is larger than the outer diameter of the
first section 11 and of the second section 12 of the central
annular region 1, 13. The intermediate element 10 may comprise an
intermediate core element 26 and a protective bush 20. The
protective bush 20 is co-centric with the intermediate core element
26. The protective bush 20 is located outside of the intermediate
core element 26. The protective bush 20 protects the intermediate
core element 26 from mechanical damage. The intermediate core
element 26 is made from a material selected from the group
consisting of (i) ceramic materials; (ii) mixed materials having
fractions of ceramic or metallic hard materials and a metallic
binding phase; and (iii) powder metallurgical materials with hard
material phases formed in-situ. The protective bush may be made
from steel. The protective bush may also be made from other
metallic materials or from a polymeric material. The protective
bush 20 may be shrunk onto the intermediate core element 26. The
outer diameter of the protective bush 20 is larger than the outer
diameter of the central annular region 1, 13. The outer diameter of
the protective bush 20 is larger than the outer diameter of the
first section 11 and of the second section 12 of the central
annular region 1, 13. The outer diameter of the protective bush 20
is smaller than the inner diameter of the shroud 22 at the position
of the intermediate element 10. The inner diameter of the
protective bush 20 may be smaller than the outer diameter of the
first and second section 11, 12 of the central annular region 1,
13. The inner diameter of the protective bush 20 may be equal to
the diameter of the circle circumscribed around the planar contact
areas 25 of the spacers 5 of the annular discs 2, 14. The
intermediate element 10 supports the shroud 22.
[0080] FIG. 1D shows a detail of FIG. 1B at the position of the end
cap 8 at the upper end of the separating device. At the upper end
of the central annular region 1, 13 and of the first section 11 of
the central annular region 1,13, an end element 32 may be provided
which forms the end-side, lateral termination of the central
annular region. The end element 32 is an annular element which is
co-centric with the perforated pipe 7. The end element 32 may be
produced from the same material as the annular discs 2, 14, 15.
Alternatively, however, corrosion-resistant steels and polymers,
such as for example fluoroelastomers or polyether ether ketone
(PEEK), may also be used. At the upper end of the central annular
region 1, 13 and of the first section 11 of the central annular
region 1, 13, a sealing bush 33 may be provided. The sealing bush
has the task of preventing the ingress of fluids that are under
pressure, into structural cavities, such as for example bevels and
gaps, between the end cap and the base pipe. Otherwise, the fluid
under pressure could exert a strong axial force on the central
annular region over the hydraulically effective annular surface of
the uppermost annular disc, which would lead to rupturing of the
annular discs. An O-ring 34 is incorporated in the sealing bush 33
on its outer circumferential surface. An O-ring may likewise be
incorporated on the inner circumferential surface of the sealing
bush. The sealing bush with the O-ring seals has the effect of
preventing that fluids under pressure can get into regions of the
separating device that have nothing to do with the filtering
function. A wear and corrosion resistant material, for example a
metallic or ceramic material or else a hard material, is used as
the material for the sealing bush. Steel may be used as material
for the sealing bush.
[0081] The region of the lower end of the separating device is
usually symmetrical to the region of the upper end of the
separating device. At the lower end of the separating device, also
an end element 32 and a sealing bush 33 may be provided.
[0082] In FIGS. 1B, 1C and 1D, only a few annular discs of the
central annular region 1, 13 are shown for ease of drawing. In
reality, of course, the stack of annular discs of the first section
11 of the central annular region 1, 13 is extending from the upper
end of the separating device, i.e. from the end element 32 at the
upper end of the separating device, to the intermediate element 10,
and the stack of annular discs of the second section 12 of the
central annular region 1, 13 is extending from the intermediate
element 10 to the lower end of the separating device, i.e. to the
end element 32 at the lower end of the separating device.
[0083] The separating device as disclosed herein may further
comprise one or more bands 29 which are provided on the lateral
surface of the perforated pipe 7 and which are inside the central
annular region 1, 13 and inside the intermediate element 10 (see
FIGS. 2E, 2F). The annular discs are placed around the one or more
bands, whereby the annular discs are centered by the one or more
bands on the perforated pipe. Also the intermediate element 10 is
placed around the one or more bands 29 and is centered by the one
or more bands. The one or more bands are also referred to as
centering bands.
[0084] The one or more bands or centering bands 29 may be provided
axially parallelly on the lateral surface of the perforated pipe.
The centering bands may also be provided helically in axial
direction on the lateral surface of the perforated pipe. The
centering bands may be provided uniformly spaced apart or with
different distances from one another.
[0085] The length of the centering bands 29 corresponds at least to
the length of the annular stack, which ensures that all of the
annular discs of the annular stack including the first and last
annular disc are centered.
[0086] The centering bands 29 may have elastic properties in a
direction perpendicular to the central axis of the central annular
region. Due to the elastic properties, the centering bands are
elastically deformable in radial direction. In some embodiments,
the centering bands may have a hollow compressible structure. In
some embodiments, the centering bands may have a fibrous
compressible structure. In some embodiments, the centering bands
may have a compact compressible structure. In some embodiments, the
centering bands may have a compressible profiled structure.
[0087] The centering bands 29 may have a planar configuration. The
centering bands may also have a profiled configuration in axial
direction of the bands.
[0088] If the centering bands 29 have a profiled configuration, the
profiled configuration may be a curvature having an outwardly
curved side. The outwardly curved side of the curvature may be
oriented towards the perforated pipe, i.e. inwards, or towards the
central annular region, i.e. outwards. Preferably, the outwardly
curved side of the curvature is oriented towards the central
annular region, i.e. outwards.
[0089] The material of the centering bands should preferably be
chosen such that it does not corrode under operating conditions and
it must be oil- water- and temperature-resistant. Metal or plastic
is suitable as the material for the centering bands, preferably
metal alloys on the basis of iron, nickel and cobalt, more
preferably steel, more preferably spring strip steel. For example,
spring strip steel with the material number 1.4310, of a
spring-hard configuration, may be used as the material for the
centering bands. The width of the centering bands may be for
example 2 to 30 mm and the thickness may be for example 0.1 to 0.5
mm.
[0090] If steel is used as the material for the centering bands, it
must be ensured when selecting the material that undesired
electrochemical reactions do not occur on contact with other
metallic structural elements of the separating device.
[0091] In some embodiments, the centering bands are fixed on the
outer surface of the perforated pipe. The centering bands may be
fixed onto the outer surface of the perforated pipe by welding,
brazing or gluing.
[0092] In some embodiments, the centering bands are not permanently
fixed on the outer surface of the perforated pipe.
[0093] The thickness and width of the centering bands should be
chosen such that the annular discs can be axially displaced on the
base pipe with a "sliding fit". This means that, in the vertical
position, the annular discs are not axially displaced under their
own weight. This is generally the case if the force for displacing
the annular discs on the base pipe in the horizontal direction,
that is to say without the influence of gravitational force, lies
between 0.1 N and 10 N, preferably between 0.5 N and 5 N.
[0094] Preferably, the intermediate element 10 is movable in axial
direction. Also the annular discs of the central annular region are
movable in axial direction. The intermediate element needs to be
freely movable in axial direction and may not be firmly connected
to the perforated pipe or the supporting structure. The free
movability of the intermediate element and the central annular
region is required for compensating the differences in thermal
expansion of the central annular region and the intermediate
element on the one hand and of the perforated pipe or the
supporting structure on the other hand. The intermediate element 10
is able to absorb mechanical shock loads in axial direction due to
its free movability in axial direction. If more than one
intermediate element is present in the separating device, the
intermediate elements need to be movable in axial direction.
[0095] The intermediate element 10 may further comprise an annular
element 27 which is co-centric with the intermediate core element
26 and which is located inside the intermediate core element 26.
The annular element 27 protects the intermediate core element 26
from mechanical damage by radial load.
[0096] The annular element 27 may be firmly connected to the
intermediate core element 26. The outer diameter of the annular
element 27 corresponds to the inner diameter of the intermediate
core element 26. For embodiments of the separating device disclosed
herein having a perforated pipe, between the annular element 27 and
the base pipe 7 there is a gap which is large enough to ensure the
free movability of the annular element 27, and therefore the free
movability of the intermediate element 10, in axial direction.
[0097] The annular element 27 may be provided with one or more
recesses 28 in axial direction distributed along the circumference
of the annular element 27. The recesses 28 are on the inner
circumference of the annular element 27. The number of recesses 28
may correspond to or may be larger than the number of bands 29
which are provided on the lateral surface of the perforated pipe 7,
and each of the bands 29 is placed in one of the recesses 28 of the
annular element 27. The annular element 27 may also be provided
with no recesses and around the bands 29.
[0098] The radial thickness of the annular element 27 at the
position of the recesses 28 is smaller than the radial thickness of
the annular element 27 outside of the recesses 28.
[0099] For annular elements 27 with no recesses on the inner
circumference, the inner diameter of the annular element 27 for
embodiments with bands 29 corresponds to the diameter of the
circumscribed circle around the bands 29. For annular elements 27
with recesses 28, the inner diameter of the annular element 27 for
embodiments with bands 29 corresponds to the diameter of the
circumscribed circle around the bands 29, at the positions of the
recesses 28.
[0100] The recesses 28 may be provided axially parallelly to the
central axis of the separating device, or may be provided axially
not parallelly to the central axis of the separating device. The
recesses may extend from the lower end of the annular element the
upper end of the annular element. The annular element 27 may also
have openings 31. The openings 31 do not extend from the lower to
the upper end of the annular element. The openings are cut through
the complete radial thickness of the annular element (see FIG. 2D).
The openings do not have a specific form, they may be quadratic,
rectangular, circular or have any other form. Preferably, the
openings are in the region of the recesses 28.
[0101] The recesses 28 which are provided in axial direction
distributed along the circumference of the annular element 27 may
be formed in such a way that their depth corresponds to the radial
thickness of the annular element 27, thereby dividing the annular
element 27 in different segments. The number of segments may
correspond to the number of recesses 28. It is also possible that
one or more of the recesses 28 of the annular element 27 have a
depth corresponding to the radial thickness of the annular element
27 and dividing the annular element in one or more segments, and
one or more further recesses 28 have a depth which is smaller than
the radial thickness of the annular element 27. For example, an
annular element having one recess with a depth corresponding to the
radial thickness of the annular element and further recesses with a
depth which is smaller than the radial thickness of the annular
element, may be easily pushed around the base pipe during assembly
of the separating device.
[0102] In some embodiments of the separating device disclosed
herein, the supporting structure for axial bracing of the central
annular region 1, 13 comprises a perforated pipe 7 which is
co-centric with and located inside the central annular region 1,
and an end cap 8 at the upper end and an end cap 9 at the lower end
of the central annular region 1, the end cap 8, 9 being co-centric
with the perforated pipe 7 and being firmly connected to the
perforated pipe 7. The intermediate element 10 is co-centric with
the perforated pipe 7. The separating device further comprises one
or more bands which are provided on the lateral surface of the
perforated pipe 7 and which are inside the central annular region
1, 13 and inside the intermediate element 10, the annular discs
being centered by the one or more bands 29 on the perforated pipe
7. The intermediate element 10 may further comprise an annular
element 27 which is co-centric with the intermediate core element
26 and which is located inside the intermediate core element 26 and
between the intermediate core element 26 and the perforated pipe 7.
The annular element 27 may be provided with one or more recesses 28
in axial direction distributed along the circumference of the
annular element 27. The number of recesses 28 is equal to or larger
than the number of bands 29 which are provided on the lateral
surface of the perforated pipe 7, and each of the bands 29 is
placed in one of the recesses 28 of the annular element 27.
[0103] The material from which the annular element 27 is made
should be resistant to compression and suitable for load transfer
from the intermediate core element 26 to the perforated pipe 7 or
to the supporting structure. The material from which the annular
element 27 is made should further have a good chemical resistance
to the treatment fluids usually used for flushing out the
separating device and stimulating the borehole, such as acids, for
example HCl or bases, for example NaOH. Furthermore, the material
of the annular element 27 should be temperature-resistant in the
temperature range of the application.
[0104] The annular element 27 may comprise a polymer, preferably
polytetrafluoroethylene (PTFE). In some embodiments, the annular
element 27 consists of a polymer, preferably
polytetrafluoroethylene (PTFE). PTFE is highly resistant to
compression, has an excellent chemical resistance and good
temperature-resistance, and can easily be machined.
[0105] The annular element 27 protects the intermediate core
element 26 from mechanical damage by radial loads. Radial loads may
arise from side impact, or from bending which occurs when the
separating device is introduced in curved boreholes. The annular
element 27 improves the resistance of the intermediate part against
radial loads. The run-in-hole procedure requires robustness of the
separating device against radial loads. Radial loads are mainly
introduced through the shroud 22 which is supported by the
intermediate element 10 or the protective bush 20, respectively.
The annular element 27 impedes that radial loads cause a radial
movement of the intermediate element 10 or the intermediate core
element 26, respectively, which would press the intermediate core
element 26 against the base pipe and could mechanically damage the
intermediate core element 26. The annular element 27 avoids that
point loads can develop on surface or edges of the intermediate
core element 26 during impact.
[0106] Another advantageous property of the annular element 27 is
related to the elastic centering bands 29 provided on the lateral
surface of the perforated pipe 7 which are bearing the intermediate
element 10. The elastic centering bands allow radial movement of
the intermediate element 10 under radial load. Under radial load,
large radial movement of the intermediate element which would
consume the clearance of the shroud protecting the central annular
region, i.e. the clearance between shroud and central annular
region, can be largely prevented by the annular element 27.
[0107] Furthermore, by the recesses 28 of the annular element 27 it
is assured that the centering bands 29 cannot move in tangential
direction on the lateral surface of the base pipe. If the centering
bands would move in tangential direction, they could lose their
centering function which could in turn adversely affect the proper
filtering function of the separating device.
[0108] The outer diameter of the annular element 27 may correspond
to the inner diameter of the intermediate core element 26.
[0109] Advantageously, the inner diameter of the annular element 27
may be adjusted as close as possible to the outer diameter of the
perforated pipe 7. With adjusting the inner diameter to that of the
perforated pipe, radial load can be directly transferred to the
perforated pipe without considerable movement. The recesses avoid
deformation of the centering bands. The radial movement can be kept
at a minimum with accurate machining. The minimum is mainly defined
by manufacturing tolerances required for assembly and easy axial
movement on the perforated pipe. The anti-adhesive properties of
PTFE are particularly advantageous and enable to move the
intermediate part lined with the annular element with low
frictional forces on the perforated pipe in axial direction during
assembly and also in operation for purposes of thermal
compensation.
[0110] PTFE is a material with large thermal expansion coefficient.
During thermal cycling such as under operation of the separating
device, the annular element tends to expand. The recesses and
openings provided in the annular element enable relaxation of
thermal stresses and therefore can reduce the risk of rupture of
the intermediate core element.
[0111] FIG. 2A shows a cross-sectional view in radial direction of
an annular element 27. FIG. 2B shows a 3D view of the annular
element of FIG. 2A. The annular element 27 has three recesses 28
which are provided in axial direction distributed along the
circumference of the annular element 27. The recesses 28 are
provided axially parallelly to the central axis of the separating
device. The recesses are formed in such a way that their depth
corresponds to the radial thickness of the annular element 27,
thereby dividing the annular element 27 in three different
segments. The number of segments corresponds to the number of
recesses 28.
[0112] FIG. 2C shows a cross-sectional view in radial direction of
a further annular element 27. FIG. 2D shows a 3D view of the
annular element of FIG. 2C. The annular element 27 has three
recesses 28 which are provided in axial direction distributed along
the inner circumference of the annular element 27. The recesses are
provided axially parallelly to the central axis of the separating
device. The radial thickness of the annular element 27 at the
position of the recesses 28 is smaller than the radial thickness of
the annular element 27 at the positions outside of the recesses.
The annular element 27 at the position of the recesses 28 should be
thick enough to ensure the mechanical stability of the annular
element as one part. The annular element 27 further may have
openings 31. In the example of FIG. 2D, two openings 31 with
rectangular shape are provided in each of the three recesses
28.
[0113] FIG. 2E shows a detail of a cross-sectional view in axial
direction of a separating device as disclosed herein. The detail of
FIG. 2E is at the position of the intermediate element 10 of the
separating device.
[0114] FIG. 2F shows the cross-sectional view in radial direction
of the separating device of FIG. 2E. The cross-sectional view of
FIG. 2F is at the position of the intermediate element 10 of the
separating device.
[0115] The intermediate element 10 comprises an intermediate core
element 26, a protective bush 20 and an annular element 27. The
intermediate core element 26 is produced from a material selected
from the group consisting of (i) ceramic materials; (ii) mixed
materials having fractions of ceramic or metallic hard materials
and a metallic binding phase; and (iii) powder metallurgical
materials with hard material phases formed in-situ.
[0116] The intermediate element 10 is placed between the first
section 11 and the second section 12 of the central annular region
1, 13. The intermediate element 10 is co-centric with the
perforated pipe 7. The outer diameter of the intermediate element
10, i.e. the outer diameter of the protective bush 20, is larger
than the outer diameter of the central annular region 1, 13. The
protective bush 20 is co-centric with the intermediate core element
26. The protective bush is located outside of the intermediate core
element 26. The protective bush 20 protects the intermediate core
element 26 from mechanical damage. The protective bush 20 may be
made from steel and may be shrunk onto the intermediate core
element 26.
[0117] The separating device with the details of FIGS. 2E and 2F
further comprises three bands 29 provided on the lateral surface of
the perforated pipe and which are inside the central annular region
1, 13 and inside the intermediate element 10. The three bands 29
may be made from spring strip steel and are elastically deformable
in radial direction. The three bands have a profiled configuration
with a curvatures having an outwardly curved side oriented towards
the central annular region 1, 13 and the intermediate element 10,
i.e. outwards.
[0118] The annular element 27 is co-centric with the intermediate
core element 26 and is located inside the intermediate core element
26. The annular element 27 protects the intermediate core element
26 from mechanical damage by radial load. The annular element 27
has three recesses 28 in axial direction distributed along the
circumference of the annular element 27. The radial thickness of
the annular element 27 at the position of the recesses is smaller
than the radial thickness of the annular element 27 at the position
outside of the recesses. Each of the three bands 29 is placed in
one of the recesses 28. The annular element 27 may be made from
polytetrafluoroethylene (PTFE). The outer diameter of the annular
element 27 corresponds to the inner diameter of the intermediate
core element 26. The inner diameter of the annular element 27
corresponds as close as possible to the outer diameter of the
perforated pipe 7, while the intermediate element 10 with the
annular element 27 inside is movable in axial direction. Under
radial load, large radial movement of the intermediate element 10
which would consume the clearance of the shroud 22 protecting the
central annular region, i.e. the clearance between shroud and
central annular region, can be largely prevented by the annular
element 27.
[0119] The annular element 27 shown in FIGS. 2E and 2F corresponds
to the annular element of FIGS. 2C and 2D. The cross-sectional view
in axial direction of FIG. 2E is at the sectional line designated
by "2E" in FIG. 2F. The cross-sectional view of the intermediate
element 10 at the upper part of FIG. 2E is at a position outside of
the recesses 28 of the annular element 27, and the cross-sectional
view of the intermediate element 10 at the lower part of FIG. 2E is
at a position of one of the three recesses 28 of the annular
element 27. The radial thickness of the annular element 27 at the
position of one of the three recesses 28 as shown in the lower part
of FIG. 2E is smaller than the radial thickness of the annular
element 27 at the position outside of the recesses 28 as shown in
the upper part of FIG. 2E. In the lower part of FIG. 2E, also the
openings 31 are shown.
[0120] The intermediate element 10 and the protective bush 20,
respectively, support the shroud 22. The inner diameter of the
shroud 22 at the position of the intermediate element 10 is larger
than the outer diameter of the central annular region 1, 13.
[0121] Each annular disc 2, 14, 15 of the separating device as
disclosed herein comprises a material independently selected from
the group consisting of (i) ceramic materials; (ii) mixed materials
having fractions of ceramic or metallic hard materials and a
metallic binding phase; and (iii) powder metallurgical materials
with hard material phases formed in-situ.
[0122] The intermediate element 10 of the separating device as
disclosed herein comprises a material selected from the group
consisting of (i) ceramic materials; (ii) mixed materials having
fractions of ceramic or metallic hard materials and a metallic
binding phase; and (iii) powder metallurgical materials with hard
material phases formed in-situ.
[0123] The intermediate core element 26 of the separating device as
disclosed herein comprises a material selected from the group
consisting of (i) ceramic materials; (ii) mixed materials having
fractions of ceramic or metallic hard materials and a metallic
binding phase; and (iii) powder metallurgical materials with hard
material phases formed in-situ.
[0124] In some embodiments, the annular discs 2, 14, 15 are
produced from, i.e. consists of a material which is independently
selected from the group consisting of (i) ceramic materials; (ii)
mixed materials having fractions of ceramic or metallic hard
materials and a metallic binding phase; and (iii) powder
metallurgical materials with hard material phases formed
in-situ.
[0125] In some embodiments, the intermediate element 10 is produced
from, i.e. consists of a material selected from the group
consisting of (i) ceramic materials; (ii) mixed materials having
fractions of ceramic or metallic hard materials and a metallic
binding phase; and (iii) powder metallurgical materials with hard
material phases formed in-situ.
[0126] In some embodiments, the intermediate core element 26 is
produced from, i.e. consists of a material selected from the group
consisting of (i) ceramic materials; (ii) mixed materials having
fractions of ceramic or metallic hard materials and a metallic
binding phase; and (iii) powder metallurgical materials with hard
material phases formed in-situ.
[0127] These materials are typically chosen based upon their
relative abrasion- and erosion-resistance to solid particles such
as sands and other mineral particles and also corrosion-resistance
to the extraction media and the media used for maintenance, such as
for example acids.
[0128] The material which the annular discs comprise can be
independently selected from this group of materials, which means
that each annular disc could be made from a different material. But
for simplicity of design and manufacturing, of course, all annular
discs of the separating device could be made from the same
material.
[0129] The intermediate element can comprise or can be made from a
different material as the annular discs. Typically, the
intermediate element comprises or is made from the same material as
the annular discs. The intermediate core element can comprise or
can be made from a different material as the annular discs.
Typically, the intermediate core element comprises or is made from
the same material as the annular discs.
[0130] The ceramic materials which the annular discs, the
intermediate element and the intermediate core element can comprise
or from which the annular discs, the intermediate element and the
intermediate core element are made can be selected from the group
consisting of (i) oxidic ceramic materials; (ii) non-oxidic ceramic
materials; (iii) mixed ceramics of oxidic and non-oxidic ceramic
materials; (iv) ceramic materials having a secondary phase; and (v)
long- and/or short fiber-reinforced ceramic materials.
[0131] Examples of oxidic ceramic materials are materials chosen
from Al.sub.2O.sub.3, ZrO.sub.2, mullite, spinel and mixed oxides.
Examples of non-oxidic ceramic materials are SiC, B.sub.4C,
TiB.sub.2 and Si.sub.3N.sub.4. Ceramic hard materials are, for
example, carbides and borides. Examples of mixed materials with a
metallic binding phase are WC--Co, TiC--Fe and TiB2-FeNiCr.
Examples of hard material phases formed in situ are chromium
carbides. An example of fiber-reinforced ceramic materials is
C/SiC. The material group of fiber-reinforced ceramic materials has
the advantage that it leads to still greater internal and external
pressure resistance of the separating devices on account of its
greater strength in comparison with monolithic ceramic.
[0132] The aforementioned materials are distinguished by being
harder than the typically occurring hard particles, such as for
example sand and rock particles, that is to say the HV (Vickers) or
HRC (Rockwell method C) hardness values of these materials lie
above the corresponding values of the surrounding rock. Materials
suitable for the annular discs of the separating device according
to the present disclosure have HV hardness values greater than 11
GPa, or even greater than 20 GPa.
[0133] All these materials are at the same time distinguished by
having greater brittleness than typical unhardened steel alloys. In
this sense, these materials are referred to herein as
"brittle-hard".
[0134] Materials suitable for the annular discs, for the
intermediate element and for the intermediate core element,
respectively, of the separating device according to the present
disclosure have moduli of elasticity greater than 200 GPa, or even
greater than 350 GPa.
[0135] Materials with a density of at least 90%, more specifically
at least 95%, of the theoretical density may be used, in order to
achieve the highest possible hardness values and high abrasion and
erosion resistances. Sintered silicon carbide (SSiC) or boron
carbide may be used as the material for the annular discs, the
intermediate element and the intermediate core element,
respectively. These materials are not only abrasion-resistant but
also corrosion-resistant to the treatment fluids usually used for
flushing out the separating device and stimulating the borehole,
such as acids, for example HCl, bases, for example NaOH, or else
steam.
[0136] Particularly suitable are, for example, SSiC materials with
a fine-grained microstructure (mean grain size.ltoreq.5 .mu.m),
such as those sold for example under the names 3M.TM. silicon
carbide type F and 3M.TM. silicon carbide type F plus from 3M
Technical Ceramics, Kempten, Germany. Furthermore, however,
coarse-grained SSiC materials may also be used, for example with a
bimodal microstructure. In one embodiment, 50 to 90% by volume of
the grain size distribution consisting of prismatic,
platelet-shaped SiC crystallites of a length of from 100 to 1500
.mu.m and 10 to 50% by volume consisting of prismatic,
platelet-shaped SiC crystallites of a length of from 5 to less than
100 .mu.m (3M.TM. silicon carbide type C from 3M Technical
Ceramics, Kempten, Germany).
[0137] Apart from these single-phase sintered SSiC materials,
liquid-phase-sintered silicon carbide (LPS-SiC) can also be used as
the material for the annular discs, the intermediate element and
the intermediate core element, respectively. An example of such a
material is 3M.TM. silicon carbide type T from 3M Technical
Ceramics, Kempten, Germany. In the case of LPS-SiC, a mixture of
silicon carbide and metal oxides is used as the starting material.
LPS-SiC has a higher bending resistance and greater toughness,
measured as a KIc value, than single-phase sintered silicon carbide
(SSiC).
[0138] In some embodiments, the material of each annular disc (2,
14, 15) is sintered silicon carbide (SSiC).
[0139] In some embodiments, the material of the intermediate
element (10) is sintered silicon carbide (SSiC).
[0140] In some embodiments, the material of the intermediate core
element (26) is sintered silicon carbide (SSiC).
[0141] The separating device as disclosed herein may further
comprise a thermal compensator 21 at the upper end or at the lower
end or at both ends of the central annular region (see FIG. 1D).
The thermal compensator 21 serves to compensate for the different
thermal expansions of the base pipe and the central annular region,
from ambient temperature to operation temperature. The thermal
compensator may for example comprise one or more springs, for
example made from a metallic material such as steel, or a
compensating bush consisting of a material on the basis of
polytetrafluoroethylene (PTFE), or a tubular double-walled
liquid-filled container, the outer walls of which are corrugated in
the axial direction.
[0142] Preferably, the separating device as disclosed herein does
not comprise a thermal compensator located near or incorporated in
the intermediate element, i.e. the intermediate element does not
comprise a thermal compensator. The thermal compensator 21 is
located at the upper end of the first section 11 of the central
annular region 1, 13 and at the lower end of the second section 12
of the central annular region 1, 13, i.e. the thermal compensator
21 is located near the end caps 8, 9. Preferably, the thermal
compensator is not located at the lower end of the first section 11
of the central annular region 1, 13, and the thermal compensator is
not located at the upper end of the second section 12 of the
central annular region 1, 13, i.e. the thermal compensator is not
located near or incorporated in the intermediate element 10.
[0143] A thermal compensator is not needed located near or
incorporated in the intermediate element of the separating device
as disclosed herein, as the intermediate element is movable in
axial direction and differences in thermal expansion between the
central annular region and the base pipe can be compensated by the
thermal compensator at the end caps and by axial movement of the
intermediate element and the first and second section of the
central annular region over the whole length of the central annular
region.
With the thermal compensator not being located near or incorporated
in the intermediate element, the filter area of the separating
device can be increased by adding more annular discs on the same
length of the separating device and thus increasing inflow area for
fluid. The inflow area of fluid is essentially not disturbed by the
intermediate element of the separating device as disclosed herein.
In separating devices of the prior art, the intermediate element
has thermal compensators and additional sealing bushes for the
thermal compensators which are both located at the upper end and
lower end of the intermediate element, and which consume a
significantly larger length of the separating device which cannot
be used for filtering purposes and which interrupts and disturbs
the inflow of fluid, thereby dividing the inflow of fluid in two
separate parts.
[0144] The intermediate element 10 of the separating device as
disclosed herein is erosion resistant to the abrasive fluid flows
and corrosion resistant to the media to be extracted and the media
used for maintenance such as acids. As the thermal compensator 21
is not located near or incorporated in the intermediate element 10,
and as the intermediate element 10 as well as the central annular
region 1, 13 are erosion and corrosion resistant, the complete
annular stack composed of central annular region 1, 13 and
intermediate element 10, or intermediate core element 26,
respectively, is erosion resistant and corrosion resistant. The
complete annular stack composed of central annular region 1, 13 and
intermediate element 10, or intermediate core element 26,
respectively, is not interrupted by any metallic or other parts not
being erosion and corrosion resistant. The inflow of fluid is not
divided into two separate parts, and the separating device as
disclosed herein can be used for harsh environments, that is for
reservoirs to be exploited with streaks having high inflow and high
erosional impact. The service life of the separating device as
disclosed herein is increased for harsh environments, that is for
reservoirs to be exploited with streaks having high inflow and high
erosional impact. Thus a separating device with a larger filter
length can be deployed, irrespective of length of zones with high
inflow and high erosional impact.
[0145] The protective bush 20 may have a radial thickness of from 1
to 20 mm. The intermediate core element 26 may have a radial
thickness of from 8 to 20 mm. The annular element 27 may have a
radial thickness of from 0.5 to 6 mm. The axial length of the
intermediate element 10 may be from 10 to 140 mm and typically is
from 40 to 70 mm.
[0146] The separating device as disclosed herein may further
comprise a number of n further intermediate elements 10, wherein n
is an integer from 1 to 10. If a number of n further intermediate
elements 10 are present, the central annular region 1, 13 further
comprises a number of n further sections, and each further
intermediate element 10 is placed between two adjacent sections of
the central annular region.
[0147] To protect the brittle-hard annular discs from mechanical
damage during handling and fitting into the borehole, the
separating device is surrounded by a tubular shroud 22 (see FIGS.
1A, 2E, 2F) that can be freely passed through by a flow. The shroud
is protecting each section of the central annular region.
[0148] This shroud may be configured for example as a coarse-mesh
screen and preferably as a perforated plate. The shroud may be
produced from a metallic material, such as from steel, particularly
from corrosion-resistant steel. The shroud may be produced from the
same material as that used for producing the base pipe.
[0149] The shroud can be held on both sides by the end caps, it may
also be firmly connected to the end caps. This fixing is possible
for example by way of adhesive bonding, screwing or pinning, the
shroud may be welded to the end caps after assembly.
[0150] The inner diameter of the shroud must be greater than the
outer diameter of the annular discs. For mechanical protection of
the annular discs of the central annular region, the inner diameter
of the shroud should be at least 0.5 mm larger than the outer
diameter of the central annular region. Typically, the inner
diameter of the shroud is at most 15 mm larger than the outer
diameter of the central annular region. The radial distance between
shroud and central annular region can be selected depending on the
radial thickness of the shroud and on the radial loads that need to
be withstand. The radial thickness of the shroud usually is from 1
to 20 mm, preferably 1 to 8 mm.
[0151] The inner diameter of the shroud being greater than the
outer diameter of the annular discs is also necessary for technical
reasons relating to flow. It has been found to be favorable in this
respect that the inner diameter of the shroud is at least 0.5 mm
and at most 15 mm greater than the outer diameter of the annular
discs. The inner diameter of the shroud may be at least 1.5 mm and
at most 8 mm greater than the outer diameter of the annular
discs.
[0152] The inner diameter of the shroud at the position of the
intermediate element is such that it fits to the outer diameter of
the intermediate element 10. If the intermediate element comprises
a protective bush 20, the inner diameter of the shroud at the
position of the intermediate element is such that it fits to the
outer diameter of the protective bush 20.
[0153] The shroud 22 may be provided in one single part. The shroud
may also be provided in two or more separate parts. On the
interface between two adjacent parts of the shroud, an intermediate
element 10 must be placed as support for the shroud. During
assembly, the shroud 22 is placed on the end caps 8, 9 and on the
intermediate element 10, and the end caps 8, 9 and the intermediate
element 10 support the shroud 22. If the shroud is provided in more
than one part, each part of the shroud can be assembled separately.
If the intermediate element 10 comprises a protective bush 20, the
shroud 22 is placed on the protective bush 20, and the end caps 8,
9 and the protective bush support the shroud 22. The shroud may or
may not be firmly connected to the intermediate element.
[0154] The distance of the intermediate elements 10 to one another
may be selected depending on the radial loads which need to be
withstand and on the thickness of the shroud, without consuming the
radial distance between shroud and central annular region.
[0155] The intermediate element 10 has the function of a spacer for
the shroud 22. By the intermediate element 10, the shroud is
positioned at a distance from the annular discs. A distance between
shroud and annular discs is maintained even if the separating
device is bended or loaded during installation or operation. If the
shroud would touch the annular discs during bending or loading, the
annular discs might be damaged which might lead to loss of sand
control.
[0156] The central annular region of the separating device
disclosed herein can, and typically does, comprise more than 3
annular discs. The number of annular discs in the central annular
region can be from 3 to 500, but also larger numbers of annular
discs are possible. For example, the central annular region can
comprise 50, 100, 250 or 500 annular discs.
[0157] The annular discs 2 and the annular discs 14, 15,
respectively, of the central annular region 1, 13 are stacked on
top of each other, resulting in a stack of annular discs. The
annular discs 2 and the annular discs 14, 15, respectively, are
stacked in such a way that a separating gap 6 for the removal of
solid particles is present in each case between adjacent annular
discs.
[0158] Every upper side 3, 16 of an annular disc 2, 14 which has
one or more spacers may be inwardly or outwardly sloping,
preferably inwardly sloping, in the regions between the spacers
(see FIGS. 3D, 4D), and every underside 17 of an annular disc 14
which has one or more spacers may be inwardly or outwardly sloping,
preferably inwardly sloping, in the regions between the spacers
(see FIG. 4D).
[0159] If the upper side, or the upper side and underside,
respectively, of the annular discs which have one or more spacers,
is inwardly or outwardly sloping in the regions between the
spacers, in the simplest case, the sectional line on the upper side
of the ring cross-section of the annular discs is straight and the
ring cross-section of the annular discs in the portions between the
spacers is trapezoidal (see FIGS. 3D, 4D), the thicker side of the
ring cross-section having to lie on the respective inlet side of
the flow to be filtered. If the flow to be filtered comes from the
direction of the outer circumferential surface of the central
annular region, the thickest point of the trapezoidal cross-section
must lie on the outside and the upper side of the annular discs is
inwardly sloping. If the flow to be filtered comes from the
direction of the inner circumferential surface of the annular disc,
the thickest point of the trapezoidal cross-section must lie on the
inside and the upper side of the annular discs is outwardly
sloping. The forming of the ring cross-section in a trapezoidal
shape, and consequently the forming of a separating gap that
diverges in the direction of flow, has the advantage that, after
passing the narrowest point of the filter gap, irregularly shaped
particles, i.e. non-spherical particles, tend much less to get
stuck in the filter gap, for example due to rotation of the
particles as a result of the flow in the gap. Consequently, a
separating device with a divergent filter gap formed in such a way
is less likely to become plugged and clogged than a separating
device in which the separating gaps have a filter opening that is
constant over the ring cross-section.
The height of the separating gap, i.e. the filter width, may be
from 50 to 1000 .mu.m. The height of the separating gap is measured
at the position of the smallest distance between two adjacent
annular discs.
[0160] The annular discs 2, 14, 15 may have a height of 1 to 12 mm.
More specifically, the height of the annular discs may be from 2 to
7 mm. The height of the annular discs is the thickness of the
annular discs in axial direction.
[0161] In some embodiments, the annular discs 14 having one or more
spacers on the upper side 16 and the underside 17 have a height of
1 to 12 mm, and the annular discs 15 which do not comprise any
spacers may have the same height as the annular discs 14 with
spacers, or may be thinner than the annular discs 14 with spacers.
The annular discs 15 may have a height of 2 to 7 mm, for example.
With the reduced height of the annular discs 15 which do not
comprise any spacers, the open flow area can be increased.
[0162] The base thickness of the annular discs is measured in the
region between the spacers and, in the case of a trapezoidal
cross-section, on the thicker side in the region between the
spacers. The axial thickness or height of the annular discs in the
region of the spacers corresponds to the sum of the base thickness
and the filter width.
[0163] The height of the spacers determines the filter width of the
separating device, that is to say the height of the separating gap
between the individual annular discs. The filter width additionally
determines which particle sizes of the solid particles to be
removed, such as for example sand and rock particles, are allowed
to pass through by the separating device and which particle sizes
are not allowed to pass through. The height of the spacers is
specifically set in the production of the annular discs.
[0164] For any particular separating device, the annular discs may
have uniform base thickness and filter width, or the base thickness
and/or filter width may vary along the length of the separating
device (e.g., to account for varying pressures, temperatures,
geometries, particle sizes, materials, and the like).
[0165] The outer contours of the annular discs may be configured
with a bevel 35, as illustrated in FIGS. 3C-3D and 4C--4D. It is
also possible to configure the annular discs with rounded edges.
This may, for some applications, represent even better protection
of the edges (versus straight edged) from the edge loading that is
critical for the materials from which the annular discs are
produced.
[0166] The circumferential surfaces (lateral surfaces) of the
annular discs may be cylindrical. However, it is also possible to
form the circumferential surfaces as outwardly convex, in order to
achieve a better incident flow.
[0167] In practice, it is expected that the annular discs are
produced with an outer diameter that is adapted to the borehole of
the extraction well provided in the application concerned, so that
the separating device according to the present disclosure can be
introduced into the borehole with little play, in order to make
best possible use of the cross-section of the extraction well for
achieving a high delivery output. The outer diameter of the annular
discs may be 20-250 mm, but outer diameters greater than 250 mm are
also possible, as the application demands.
[0168] The radial ring width of the annular discs may lie in the
range of 8-20 mm. These ring widths are suitable for separating
devices with base pipe diameters in the range of 6 cm to 14 cm
(23/8 to 51/2 inches).
[0169] The spacers arranged on the upper side, or on the upper side
and the underside, respectively, of the annular discs have
planiform contact with the adjacent annular disc. The spacers make
a radial throughflow possible and therefore may be arranged
radially aligned on the first major surface of the annular discs,
or on the second major surface of the annular discs, respectively.
The spacers may, however, also be aligned at an angle to the radial
direction.
[0170] The transitions between the surface of the annular discs,
i.e. the upper side, or the upper side and the underside of the
annular discs, and the spacers are typically not formed in a
step-shaped or sharp-edged manner. Rather, the transitions between
the surface of the annular discs and the spacers are typically
configured appropriately for the material from which the annular
discs are made, i.e. the transitions are made with radii that are
gently rounded. This is illustrated in FIGS. 3E and 4E.
[0171] The contact area of the spacers, that is to say the planar
area with which the spacers are in contact with the adjacent
annular disc are not particularly limited, and may be, for
instance, rectangular, round, rhomboidal, elliptical, trapezoidal
or else triangular, while the shaping of the corners and edges
should always be appropriate for the material from which the
annular discs are made, e.g. rounded.
[0172] Depending on the size of the annular discs, the contact area
25 of the individual spacers is typically between 4 and 100
mm.sup.2.
[0173] The spacers 5 may be distributed over the circumference of
the annular discs (see FIGS. 3A and 4A). The spacers 5 may be
distributed homogeneously or non-homogeneously over the
circumference of the annular discs. The number of spacers may be
even or odd.
[0174] The annular discs of the separating device disclosed herein
may be prepared by the methods that are customary in technical
ceramics or powder metallurgy, that is to say by die pressing of
pressable starting powders and subsequent sintering. The annular
discs may be formed on mechanical or hydraulic presses in
accordance with the principles of "near-net shaping", debindered
and subsequently sintered to densities>90% of the theoretical
density. The annular discs may be subjected to 2-sided facing on
their upper side and underside.
[0175] In FIGS. 3A-3L, one embodiment of a central annular region
of a separating device as disclosed herein is represented. FIGS.
3A-3F show various details of an individual annular disc 2 of the
central annular region 1. FIGS. 3G-3L show the central annular
region 1 constructed from annular discs 2 of FIGS. 3A-3F,
representing various details of the stack of annular discs. FIG. 3A
shows a plan view of the upper side 3 of the annular disc 2, FIG.
3B shows a cross-sectional view along the sectional line denoted in
FIG. 3A by "3B", FIGS. 3C-3D show enlarged details of the
cross-sectional view of FIG. 3B. The enlarged detail of FIG. 3C is
in the region of a spacer, the enlarged detail of FIG. 3D is in the
region between two spacers. FIG. 3F shows a 3D view of the annular
disc 2, and FIG. 3E shows a 3D representation along the sectional
line denoted in FIG. 3A by "3E". FIG. 3G shows a plan view of the
central annular region 1 constructed from annular discs 2 of FIGS.
3A-3F, FIG. 3H shows a cross-sectional view along the sectional
line denoted in FIG. 3G by "3H", FIGS. 3I-3J show enlarged details
of the cross-sectional view of FIG. 3H. The enlarged detail of FIG.
3I is in the region of a spacer, the enlarged detail of FIG. 3J is
in the region between two spacers. FIG. 3K shows a 3D view of the
central annular region 1, and FIG. 3L shows a 3D representation
along the sectional line denoted in FIG. 3G by "3L".
[0176] The removal of the solid particles takes place at the inlet
opening of a separating gap 6, which may be divergent, i.e.
opening, in the direction of flow (see FIGS. 3D and 3J) and is
formed between two annular discs lying one over the other. The
annular discs are designed appropriately for the materials from
which the annular discs are produced and the operational
environment intended for the devices made with such annular discs,
e.g., materials may be chosen for given pressure, temperature and
corrosive operating conditions, and so that cross-sectional
transitions may be configured without notches so that the
occurrence of flexural stresses is largely avoided by the
structural design.
[0177] The upper side 3 of each annular disc 2 has fifteen spacers
5 distributed over its circumference. The underside 4 does not
comprise any spacers. The spacers 5 are of a defined height, with
the aid of which the height of the separating gap 6 (gap width of
the filter gap, filter width) is set. The spacers are not
separately applied or subsequently welded-on spacers, they are
formed directly in production, during the shaping of the annular
discs.
[0178] The contact area 25 of the spacers 5 is planar (see FIGS.
3C, 3E), so that the spacers 5 have a planar contact area with the
underside 4 of the adjacent annular disc. The upper side 3 of the
annular discs is plane-parallel with the underside 4 of the annular
discs in the region of the contact area 25 of the spacers 5, i.e.
in the region of contact with the adjacent annular disc. The
underside 4 of the annular discs is formed as smooth and planar and
at right angles to the disc axis and the central axis of the
central annular region. At the planar contact area of the spacers,
the annular discs contact the respective adjacent annular disc.
[0179] The upper side 3 of an annular disc 2 having fifteen spacers
5 is inwardly sloping, in the regions between the spacers. The ring
cross-section of the annular discs in the portions between the
spacers is trapezoidal (see FIG. 3D), the thicker side of the ring
cross-section lying on the outside, i.e. on the inlet side of the
flow to be filtered.
[0180] In FIGS. 4A-4L, a further embodiment of a central annular
region of a separating device as disclosed herein is represented.
FIGS. 4A-4F show various details of individual annular discs 14 of
the central annular region 13. FIGS. 4G-4L show the central annular
region 13 constructed from annular discs 14 and 15, representing
various details of the stack of annular discs. FIG. 4A shows a plan
view of the upper side 16 and of the underside 17 of the annular
disc 14, FIG. 4B shows a cross-sectional view along the sectional
line denoted in FIG. 4A by "4B", FIGS. 4C-4D show enlarged details
of the cross-sectional view of FIG. 4B. The enlarged detail of FIG.
4C is in the region of the spacers, the enlarged detail of FIG. 4D
is in the region between the spacers. FIG. 4F shows a 3D view of
the annular disc 14, and FIG. 4E shows a 3D representation along
the sectional line denoted in FIG. 4A by "4E". FIG. 4G shows a plan
view of the central annular region 13 constructed from annular
discs 14 and 15, FIG. 4H shows a cross-sectional view along the
sectional line denoted in FIG. 4G by "4H",
[0181] FIGS. 4I-4J show enlarged details of the cross-sectional
view of FIG. 4H. The enlarged detail of FIG. 4I is in the region of
a spacer, the enlarged detail of FIG. 4J is in the region between
the spacers. FIG. 4K shows a 3D view of the central annular region
13, and FIG. 4L shows a 3D representation along the sectional line
denoted in FIG. 4G by "4L".
[0182] The stack of annular discs 13 is composed of annular discs
14 and 15 which are stacked in an alternating manner. Every second
annular disc in the stack is an annular disc 14 having fifteen
spacers 5 on the upper side 16 of the annular disc 14 distributed
over its circumference (see FIG. 4A) and fifteen spacers 5 on the
underside 17 of the annular disc 14 distributed over its
circumference. The plan view of the upper side 16 of FIG. 4A is
identical to the plan view of the underside 17. The spacers 5 of
the annular discs 14 are of a defined height, with the aid of which
the height of the separating gap 6 (gap width of the filter gap,
filter width) is set. The spacers are not separately applied or
subsequently welded-on spacers, they are formed directly in
production, during the shaping of the annular discs.
[0183] The respectively adjacent annular discs of the annular discs
14 in the stack of annular discs 13 are annular discs 15 as shown
in FIGS. 4H-4J. The upper side 18 and the underside 19 of the
annular discs 15 do not comprise any spacers.
[0184] The removal of the solid particles takes place at the inlet
opening of a separating gap 6, which may be divergent, i.e.
opening, in the direction of flow (see FIGS. 4D and 4J) and is
formed between two adjacent annular discs lying one over the other.
The annular discs are designed appropriately for the materials from
which the annular discs are produced and the operational
environment intended for the devices made with such annular discs,
e.g., materials may be chosen for given pressure, temperature and
corrosive operating conditions, and so that cross-sectional
transitions may be configured without notches so that the
occurrence of flexural stresses is largely avoided by the
structural design.
[0185] The contact area 25 of the spacers 5 is planar (see FIGS.
4C, 4E), so that the spacers 5 have a planar contact area with the
underside 19 or upper side 18 of the adjacent annular disc 15. The
upper side 16 of the annular discs 14 is plane-parallel with the
underside 17 of the annular discs 14 in the region of the contact
area 258 of the spacers 5, i.e. in the region of contact with the
adjacent annular disc. At the planar contact area of the spacers,
the annular discs contact the respective adjacent annular disc
15.
[0186] The upper side 18 and the underside 19 of the annular discs
15 is formed as smooth and planar and at right angles to the disc
axis and the central axis of the central annular region.
[0187] The upper side 16 and the underside 17 of an annular disc 14
having fifteen spacers 5 is inwardly sloping, in the regions
between the spacers 5. The ring cross-section of the annular discs
in the portions between the spacers is trapezoidal (see FIG. 4D),
the thicker side of the ring cross-section lying on the outside,
i.e. on the inlet side of the flow to be filtered.
[0188] The separating device according to the present disclosure
may be used for removing solid particles from a fluid. A fluid as
used herein means a liquid or a gas or combinations of liquids and
gases.
[0189] The separating device according to the present disclosure
may be used in extraction wells in oil and/or gas reservoirs for
separating solid particles from volumetric flows of mineral oil
and/or natural gas. The separating device may also be used for
other filtering processes for removing solid particles from fluids
outside of extraction wells, processes in which a great abrasion
resistance and a long lifetime of the separating device are
required, such as for example for filtering processes in mobile and
stationary storage installations for fluids or for filtering
processes in naturally occurring bodies of water, such as for
instance in the filtering of seawater. The separating device
disclosed herein can also be used in a process for extracting ores
and minerals. In the extraction of ore and many other minerals,
there are problems of abrasion and erosion in the removal of solid
particles from fluid flows. The separating device according to the
present disclosure is particularly suitable for the separation of
solid particles from fluids, in particular from mineral oil,
natural gas and water, in extraction wells in which high and
extremely high rates of flow and delivery volumes occur.
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