U.S. patent application number 10/498812 was filed with the patent office on 2005-04-28 for externally mountable spiral adaptor.
Invention is credited to Hughes, Paul.
Application Number | 20050087935 10/498812 |
Document ID | / |
Family ID | 4171031 |
Filed Date | 2005-04-28 |
United States Patent
Application |
20050087935 |
Kind Code |
A1 |
Hughes, Paul |
April 28, 2005 |
Externally mountable spiral adaptor
Abstract
An adaptor that can be used with rotary fluid equipment will
protect mechanical seals and/or packing material adjacent a seal
cavity (18) of the equipment. The adaptor includes an annular body
(30) with a central bore (32) adapted to receive a shaft (12) of
the equipment. When used with mechanical seals the adaptor is
receivable in the cavity at the entrance thereto and it has a
portion which surface which effects contact with a complementary
surface of the seal. When used with packing the adaptor fits within
the cavity and defines an outboard extension in which the packing
can be received. The bore defines two portions, one of which is
close to the shaft (52) and another portion (54) which flares
outwardly from the one portion towards the outboard end of the
adaptor. Each bore portion has a spiral groove (56,58) therein,
which groove serves to redirect contaminant material contained in
fluids surrounding the shaft away from the seal cavity.
Inventors: |
Hughes, Paul; (Halifax Nova
Scotia, CA) |
Correspondence
Address: |
JONES, TULLAR & COOPER, P.C.
P.O. BOX 2266 EADS STATION
ARLINGTON
VA
22202
|
Family ID: |
4171031 |
Appl. No.: |
10/498812 |
Filed: |
June 21, 2004 |
PCT Filed: |
December 12, 2002 |
PCT NO: |
PCT/CA02/02002 |
Current U.S.
Class: |
277/610 |
Current CPC
Class: |
F16J 15/406 20130101;
F04D 29/106 20130101; F16J 15/3404 20130101; F16J 15/189 20130101;
F16J 15/183 20130101 |
Class at
Publication: |
277/610 |
International
Class: |
H02G 015/04 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 3, 2002 |
CA |
2,366,696 |
Claims
1. A spiral adaptor for location at an entrance to an annular seal
cavity of rotating equipment, such seal cavity being defined by a
outer cylindrical surface of a rotatable shaft of such equipment
and a shaft housing surrounding at least a portion of said shaft,
said cavity having a bottom end, an entrance end and an outer
cylindrical surface, said equipment including a mechanical seal
positioned outboard of said shaft housing adjacent said entrance to
said seal cavity, said adaptor comprising: an annular adaptor body
having a central bore therethrough; said adaptor body including a
first annular portion receivable within said seal cavity at said
entrance thereto and a second annular portion of greater diameter
than said first annular portion, said second annular portion having
an inboard radial surface adapted for contact with a complementary
face of said shaft housing and an outboard radial surface adapted
for contact with a complementary face of said mechanical seal; said
bore including a first portion defining an annular gap with said
shaft outer cylindrical surface when said adaptor is in its
operating position and a second portion which flares outwardly from
said first bore portion towards said outboard radial surface, said
first and second bore portions each including a spiral groove
formed therein, the hand thereof being in the same direction as the
rotation of said shaft, said groove serving to redirect contaminant
material contained in fluids surrounding said shaft away from said
seal cavity.
2. The spiral adaptor of claim 1 wherein said first annular portion
of said adaptor body has an outer cylindrical surface adapted for a
tight fit within said seal cavity, said outer cylindrical surface
including a circumferential groove therein for reception of an
annular seal member adapted for sealing engagement with said outer
cylindrical surface of said seal cavity.
3. The spiral adaptor of claim 1 wherein said first annular portion
of said adaptor body acts as a locating boss for positioning said
spiral adaptor at said cavity entrance
4. The spiral adaptor of claim 1 wherein said first annular portion
of said adaptor body has an outer cylindrical surface adapted for a
tight fit within said seal cavity, said outer cylindrical surface
including at least a pair of axially spaced apart circumferential
grooves therein, each for reception of an annular seal member
adapted for sealing engagement with said outer cylindrical surface
of said seal cavity.
5. The spiral adaptor of claim 1 wherein said inboard radial
surface of said adaptor body second annular portion has a ribbed
gasket surface formed integrally therewith for sealing engagement
with said complementary face of said shaft housing.
6. The spiral adaptor of claim 1 wherein said inboard radial
surface of said adaptor body second annular portion has an annular
groove formed therein for reception of an annular sealing member
for sealing engagement with said complementary face of said shaft
housing.
7. The spiral adaptor of claim 1 wherein the axial extent of said
adaptor body first portion may be greater than, lesser than or
equal to the axial extent of said adaptor body second portion.
8. The spiral adaptor of claim 1 including a shutoff mechanism
contained therein, said shutoff mechanism comprising a
circumferential groove formed in said first bore portion, a
flexible sealing ring contained within said circumferential, and a
passage in said annular body communicating a source of pressurized
fluid with said circumferential groove for pressing said flexible
ring against said shaft.
9. The spiral adaptor of claim 1 in combination with an insert
positionable within said seal cavity adjacent the bottom end
thereof, said insert comprising an annular insert body receivable
within said seal cavity and having a central bore therethrough;
said central bore including a first portion defining an annular gap
with said shaft outer cylindrical surface when said insert is in
its operating position and a second portion which flares outwardly
from said first bore portion towards an outboard end of said
insert, said first and second bore portions each including a spiral
groove formed therein, the hand thereof being in the same direction
as the rotation of said shaft, said groove serving to redirect
contaminant material contained in fluids within said seal cavity
towards said spiral adaptor.
10. A spiral adaptor for location at an entrance to an annular seal
cavity of rotating equipment, such seal cavity being defined by a
outer cylindrical surface of a rotatable shaft of such equipment
and a shaft housing surrounding at least a portion of said shaft,
said cavity having a bottom end, an entrance end and an outer
cylindrical surface, said equipment including a mechanical seal
positioned outboard of said shaft housing adjacent said entrance to
said seal cavity, said adaptor comprising: an annular adaptor body
receivable within said seal cavity at said entrance thereto and
having a central bore therethrough; said adaptor body including an
outboard radial surface adapted for contact with a complementary
face of said mechanical seal; said bore including a first portion
defining an annular gap with said shaft outer cylindrical surface
when said adaptor is in its operating position and a second portion
which flares outwardly from said first bore portion towards said
outboard radial surface, said first and second bore portions each
including a spiral groove formed therein, the hand thereof being in
the same direction as the rotation of said shaft, said groove
serving to redirect contaminant material contained in fluids
surrounding said shaft away from said seal cavity.
11. The spiral adaptor of claim 10 wherein said adaptor body has an
outer cylindrical surface adapted for a tight fit within said
cavity, said outer cylindrical surface including at least one
circumferential groove therein for reception of an annular seal
member adapted for sealing engagement with said outer cylindrical
surface of said seal cavity.
12. The spiral adaptor of claim 1 wherein said spiral groove formed
in said adaptor body bore first portion leads smoothly into said
spiral groove formed in said adaptor body bore second portion.
13. The spiral adaptor of claim 1 wherein said spiral groove has
radial and non-radial surface portions, the non-radial portion
extending into the adaptor body from the adaptor body bore and the
radial portion extending generally radially from the inner end of
the non-radial portion back towards the adaptor body bore.
14. The spiral adaptor of claim 1 wherein said adaptor body bore
includes an intermediate portion between said first and second
portions and of diameter greater than that of said first portion,
there being a flared transition section between said first and
intermediate portions, said intermediate and flared transition
portions each having a spiral groove formed therein.
15. A spiral adaptor for location within an annular seal cavity of
rotating equipment, such seal cavity being defined by a outer
cylindrical surface of a rotatable shaft of such equipment and a
shaft housing surrounding at least a portion of said shaft, said
cavity having a bottom end, an entrance end and an outer
cylindrical surface, said adaptor comprising: an annular adaptor
body receivable within said seal cavity and having a central bore
therethrough; said adaptor body including a first annular body
portion positionable at said bottom end of said seal cavity and a
second annular body portion outboard of said first body portion;
said bore including a first portion defining an annular gap with
said shaft outer cylindrical surface when said adaptor is in its
operating position and a second portion which flares outwardly from
said first bore portion towards a radially inwardly tapering
central portion, said first, second and central bore portions each
including a spiral groove formed therein, the hand thereof being in
the same direction as the rotation of said shaft, said groove
serving to redirect contaminant material contained in fluids
surrounding said shaft away from said seal cavity; and said adaptor
also including an annular extension portion extending from said
second annular portion to an outboard end of said adaptor, said
extension portion including a blind bore therein which, with said
shaft outer cylindrical surface defines an annular cavity for
reception of one or more packing rings.
16. The spiral adaptor of claim 15 wherein said second annular
portion includes an outer circumferential groove therein for
communication with a source of flushing fluid, and at least one
passage leading from said circumferential groove through said
adaptor body to said bore central portion.
17. The spiral adaptor of claim 15 wherein each of said first
annular portion and said extension portion includes at least one
outer circumferential groove therein for reception of an annular
sealing member.
18. The spiral adaptor of claim 15 wherein said extension portion
terminates at its outboard end at a radially outwardly extending
flange.
19. The spiral adaptor of claim 10 wherein said spiral groove has
radial and non-radial surface portions, the non-radial portion
extending into the adaptor body from the adaptor body bore and the
radial portion extending generally radially from the inner end of
the non-radial portion back towards the adaptor body bore.
20. The spiral adaptor of claim 10 wherein said adaptor body bore
includes an intermediate portion between said first and second
portions and of diameter greater than that of said first portion,
there being a flared transition section between said first and
intermediate portions, said intermediate and flared transition
portions each having a spiral groove formed therein.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to an adaptor that can be used
with rotatable fluid equipment, such as pumps, and which will
protect mechanical seals and packing adjacent a seal cavity of the
equipment.
BACKGROUND OF THE INVENTION
[0002] Spiral throat bushings are available from EnviroSeal
Engineering Products Ltd. of Waverley, Nova Scotia, Canada under
the SpiralTrac.TM. name. These patented devices (U.S. Pat. No.
5,553,868) have a spiral groove formed in a sloping face thereof
and are generally positioned at the "bottom" of a seal cavity
defined in part by a rotating shaft, a shaft housing, and a throat
structure. The seal cavity typically, as well, may be filled with
conventional packing or it may include a mechanical seal adjacent
the end opposite the throat structure. These spiral bushings are
intended to remove particulate material that may accumulate within
the seal cavity during operation of the equipment, and may be
augmented by flush fluids to help in material removal. The result
of using these "internal" spiral throat bushings has been increased
seal or packing life due to a significant reduction in wear.
[0003] Mechanical seals are designed to prevent leakage of process
fluid to atmosphere, and are typically offered in a split or solid
cartridge design. Typically, the seal is fastened to the face of
the seal cavity housing by some mechanical means, such as threaded
bolts or rods. The operation of the rotating equipment could be
enhanced further if there was less particulate material entering
the seal cavity from the vicinity of the mechanical seal.
[0004] Packing material is typically provided in annular rings and
one or more such packing rings can be placed in a seal cavity and
surrounding the rotating shaft. Again, operation of rotating
equipment could be enhanced further if there were less particulate
material entering the seal cavity past or from the vicinity of such
packing material
SUMMARY OF THE INVENTION
[0005] This need for reduction of particulate or contaminant
material from the exterior of the seal cavity has led to the
development of an "external" spiral adaptor or bushing that is
positioned between the mechanical seal or packing and the end face
of the seal cavity housing and which serves to increase the
cleanliness of the environment in which the sealing mechanism,
whether mechanical seal or packing, functions.
[0006] The advantage to this arrangement is that with the spiral
adaptor being located closer to the sealing mechanism the existing
patented technology of the bushing or adaptor will protect the
sealing mechanism from particulate material entering at or near the
sealing area. By doing this, the intent is to allow the sealing
mechanism to operate in a cleaner environment with the result being
extended operating life. The externally mounted design is available
in a split and non-split (solid) design. The advantage of the split
design is that the equipment does not have to be disassembled and
the benefit of the spiral adaptor technology can be utilized. There
are enormous savings for the customer if this can be avoided. The
advantage of the solid design resides in the spiral adaptor
technology and the benefit of a cleaner operating environment.
[0007] The externally designed spiral adaptor of this invention
will create an enclosed cavity for the rotating component of a
mechanical seal. Furthermore, it is possible to dimension the
outboard side of the device to accept virtually any mechanical seal
or packing material that is available on the market. The mechanical
seal or packing being utilized will determine the cavity depth of
the externally mountable spiral adaptor of the invention.
[0008] In summary of the foregoing, and in one embodiment, the
present invention may be broadly set forth as a spiral adaptor for
location at an entrance to an annular seal cavity of rotating
equipment, such seal cavity being defined by a outer cylindrical
surface of a rotatable shaft of such equipment and a shaft housing
surrounding at least a portion of the shaft, the cavity having a
bottom end, an entrance end and an outer cylindrical surface, the
equipment including a mechanical seal positioned outboard of the
shaft housing adjacent the entrance to the seal cavity. The adaptor
comprises: an annular adaptor body having a central bore
therethrough, the adaptor body including a first annular portion
receivable within the seal cavity at the entrance thereto and a
second annular portion of greater diameter than the first annular
portion, the second annular portion having an inboard radial
surface adapted for contact with a complementary face of the shaft
housing and an outboard radial surface adapted for contact with a
complementary face of the mechanical seal; the bore including a
first portion defining an annular gap with the shaft outer
cylindrical surface when the adaptor is in its operating position
and a second portion which flares outwardly from the first bore
portion towards said outboard radial surface, the first and second
bore portions each including a spiral groove formed therein, the
hand thereof being in the same direction as the rotation of the
shaft, the groove serving to redirect contaminant material
contained in fluids surrounding the shaft away from said the
cavity.
[0009] In another related embodiment the present invention may be
considered as providing a spiral adaptor for location at an
entrance to an annular seal cavity of rotating equipment, such seal
cavity being defined by a outer cylindrical surface of a rotatable
shaft of such equipment and a shaft housing surrounding at least a
portion of the shaft, the cavity having a bottom end, an entrance
end and an outer cylindrical surface, the equipment including a
mechanical seal positioned outboard of the shaft housing adjacent
the entrance to the seal cavity, the adaptor comprising: an annular
adaptor body receivable within the seal cavity at the entrance
thereto and having a central bore therethrough; the adaptor body
including an outboard radial surface adapted for contact with a
complementary face of the mechanical seal; the bore including a
first portion defining an annular gap with the shaft outer
cylindrical surface when the adaptor is in its operating position
and a second portion which flares outwardly from the first bore
portion towards the outboard radial surface, the first and second
bore portions each including a spiral groove formed therein, the
hand thereof being in the same direction as the rotation of the
shaft, the groove serving to redirect contaminant material
contained in fluids surrounding the shaft away from the seal
cavity.
[0010] In yet another related embodiment the present invention may
be considered as providing a spiral adaptor for location within an
annular seal cavity of rotating equipment, such seal cavity being
defined by a outer cylindrical surface of a rotatable shaft of such
equipment and a shaft housing surrounding at least a portion of the
shaft, the cavity having a bottom end, an entrance end and an outer
cylindrical surface, the adaptor comprising: an annular adaptor
body receivable within the seal cavity and having a central bore
therethrough; the adaptor body including a first annular body
portion positionable at the bottom end of the seal cavity and a
second annular body portion outboard the first body portion; the
bore including a first portion defining an annular gap with the
shaft outer cylindrical surface when the adaptor is in its
operating position and a second portion which flares outwardly from
the first bore portion towards a radially inwardly tapering central
portion, the first, second and central bore portions each including
a spiral groove formed therein, the hand thereof being in the same
direction as the rotation of the shaft, the groove serving to
redirect contaminant material contained in fluids surrounding the
shaft away from said the cavity; and the adaptor also including an
annular extension portion extending from the second annular portion
to an outboard end of the adaptor, the extension portion including
a blind bore therein which, with the shaft outer cylindrical
surface, defines an annular cavity for reception of one or more
packing rings.
[0011] The present invention will now be described with reference
to the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 illustrates in partial cross-section a typical
environment for a spiral adaptor of the present invention, as
located at the entrance to the seal cavity of rotating fluid
equipment.
[0013] FIG. 2 illustrates in enlarged cross-section a first
embodiment of the spiral adaptor of the present invention.
[0014] FIG. 3 illustrates in enlarged cross-section a second
embodiment of the spiral adaptor of the present invention.
[0015] FIG. 4 illustrates in enlarged cross-section a third
embodiment of the spiral adaptor of the present invention.
[0016] FIG. 5 illustrates in enlarged cross-section a fourth
embodiment of the spiral adaptor of the present invention.
[0017] FIG. 6 illustrates in enlarged cross-section a fifth
embodiment of the spiral adaptor of the present invention.
[0018] FIG. 7 illustrates in enlarged cross-section a sixth
embodiment of the spiral adaptor of the present invention.
[0019] FIG. 8 illustrates in enlarged cross-section a seventh
embodiment of the spiral adaptor of the present invention.
[0020] FIG. 9 illustrates in enlarged cross-section an eighth
embodiment of the spiral adaptor of the present invention.
[0021] FIG. 10 illustrates in enlarged cross-section a ninth
embodiment of the spiral adaptor of the present invention.
[0022] FIG. 11 illustrates in enlarged cross-section a tenth
embodiment of the spiral adaptor of the present invention.
[0023] FIG. 12 illustrates in enlarged cross-section the spiral
adaptor of the present invention as utilized in the arrangement of
FIG. 11.
[0024] FIG. 13 illustrates in enlarged cross-section an eleventh
embodiment of the spiral adaptor of the present invention.
[0025] FIG. 14 illustrates in enlarged cross-section the spiral
adaptor of the present invention as utilized in the arrangement of
FIG. 13.
DESCRIPTION OF THE PREFERRED AND OTHER EMBODIMENTS
[0026] FIG. 1 of the drawings illustrates a typical environment in
which a spiral adaptor of the present invention will be useful.
Such environment is found in rotating fluid equipment, which
equipment 10 will include a rotatable shaft 12, bearingly mounted
on an axis A, and surrounded at least in part by a shaft housing
14. The housing 14 defines with an outer cylindrical surface 16 of
the shaft 12 an annular seal cavity 18 having a bottom end defined
by radial flange 20, an entrance end 22 and an outer cylindrical
surface 24. A mechanical seal 26 is typically positioned outboard
of the seal cavity adjacent the shaft housing at the entrance to
the seal cavity. The details of the mechanical seal are not germane
to the present invention and will not be described herein.
[0027] As seen in FIG. 1 there is an external spiral adaptor 28 of
the present invention located at the entrance to the seal cavity,
positioned so as to be between the housing 14 and the mechanical
seal 26. The adaptor 28 is described in greater detail with
reference to FIG. 2.
[0028] Turning now to FIG. 2 a spiral adaptor 28 in accordance with
the present invention will now be described. It is expected that
this embodiment will be the one most commonly used in existing and
new rotary equipment and it is the one depicted in position in FIG.
1. As with all of the embodiments to the described herein the
spiral adaptor 28 can be machined from a single billet of suitable
material, such as stainless steel, PTFE, or PEEK. A composite such
as PTFE or PEEK is preferred since the machining time therefor is
much less than with a metal. As is common in the adaptor art the
spiral adaptor of the present invention may be formed as a solid
(unitary) ring or it may be split into two or more sections or
segments, typically along a vertical or a horizontal axis. If a
split adaptor is used then the sections or segments thereof will
have suitable mating pins and holes to align the sections or
segments together, as well as appropriate fastening means, such as
machine screws, to hold them together.
[0029] The adaptor 28 has an annular adaptor body 30 having a
central bore 32 extending therethrough. The adaptor body includes a
first annular portion 34 which is adapted for a tight fit within
the seal cavity 18 at the entrance 22 thereto. The annular portion
34 may include a circumferential groove 36 therein for reception of
an annular sealing member 38 (FIG. 1) such as an O-ring which will
have sealing engagement with the outer cylindrical surface 24 of
the seal cavity 18 when the spiral adaptor is in position. The
adaptor body includes a second annular portion 40 of diameter
greater than that of the first annular portion 34. The second
annular portion 40 has an inboard radial surface 42 adapted for
contact with a complementary face surface 44 of the shaft housing
14 and an outboard radial surface 46 adapted for contact with a
complementary face surface 48 of the mechanical seal 26. The
inboard radial surface 42 may be provided with a ribbed gasket
surface 50 for sealing engagement with the complementary surface 44
of the housing 14.
[0030] It will be seen that the adaptor body bore 32 includes two
portions, a first portion 52 which defines an annular gap G (FIG.
1) with the outer cylindrical surface 16 of the shaft 12 and a
second portion 54 which flares outwardly from the outboard end of
the first portion 52 towards the outboard radial surface 46 of the
second annular body portion 40. Each of the bore portions 52, 54 is
provided with its own spiral groove 56, 58 respectively therein,
the hand of the spiral grooves 56, 58 being in the same direction
of the rotation of the shaft 12. The grooves 56, 58 serve to
redirect any contaminant-containing fluids away from the seal
cavity such that damaging particulate material or other
contaminants contained within operating fluids will not enter the
seal cavity.
[0031] The grooves 56, 58 are similar to those described in
aforementioned U.S. Pat. No. 5,553,868 in that they include both
radial and non-radial portions. The non-radial portions 60 extend
non-radially into the body of the adaptor from the respective bore
portion and the radial portions 62 extend radially from the inner
end of the respective non-radial portion back towards the bore. The
groove 56 of the first bore portion 52 will lead smoothly into the
groove 58 of the second or flared bore portion 54.
[0032] Although not shown specifically within the drawings there
could be one or more additional grooves formed within the adaptor
body and located between the first and second grooves 56, 58 also
as described in U.S. Pat. No. 5,553,868.
[0033] FIG. 3 illustrates a variation on the embodiment of FIG. 2
which is intended to accommodate a situation in which there are
restrictions on available axial space in which the spiral adaptor
can be received. In this situation the adaptor 64 of FIG. 3 could
be utilized, it being noted that the first annular body portion 66
is considerably shorter in axial length than the second annular
body portion 68. In this embodiment the first body portion 66 acts
only as a locating boss to hold the spiral adaptor in position
while the equipment is being assembled, such that the adaptor is
self-centring with respect to the seal cavity. With this embodiment
the first annular body portion 66 is not long enough to include a
circumferential groove and sealing member as is found in the
embodiment of FIG. 2.
[0034] There may be situations in which there is a need to extend
the first annular body portion of the spiral adaptor deeply into
the seal cavity, perhaps all the way to the bottom 18 thereof. The
spiral adaptor 70 of FIG. 4 will accomplish this need in that the
first annular portion 72 thereof is considerably longer than the
second annular portion 74. The first annular portion 72 is
preferably provided with at least two circumferential grooves 76,
each of which can receive a suitable sealing member, such as an
O-ring as described for the first embodiment, to effect sealing
engagement with the outer cylindrical surface 24 of the seal cavity
18.
[0035] There may be situations in which there has been substantial
wear on the shaft 12 in the vicinity of the mechanical seal 26 and
it becomes desirable to reposition the seal 26 further away from
the shaft housing 14 than before. The spiral adaptor 80 of FIG. 5
can be used in these situations, it being noted that the second
annular body portion 84 thereof is considerably greater in axial
length than the first annular portion 82 thereof. With this
embodiment the mechanical seal 26 can be moved outwardly on the
shaft 12 to a smoother area of the shaft or seal, with the greater
length of the second annular body portion bridging the distance
from the housing 14 to the mechanical seal 26. Another advantage to
this embodiment is that the mechanical seal is positioned closer to
the main bearing support of the equipment where there is less
chance of vibration affecting the performance of the seal.
[0036] It will be appreciated that there are many designs of seal
cavities and that not all such designs will conform generally to
the typical design illustrated in FIG. 1. One such non-conforming
design is the so-called "big bore" design where a larger more
expensive mechanical seal is required. By using the spiral adaptor
90 of FIG. 6 it is possible to reduce the radial cross-section of
the adaptor, allowing for a smaller, less expensive, mechanical
seal to be used. In this case the adaptor body 92 does not include
a second annular body portion of diameter greater than that of the
first annular body portion, i.e. the body has a single outer
diameter over its entire length. Otherwise the features of the
adaptor are the same as those of the first embodiment. This
arrangement can substantially reduce costs for the customer.
[0037] FIG. 7 illustrates a spiral adaptor 100 that is advantageous
in those situations where the complementary face surface 44 of the
shaft housing 14 is eroded or damaged and the ribbed gasket surface
50 will not provide sufficient sealing contact with the face
surface 44. In this embodiment an annular groove 102 is machined in
the inboard radial surface 42 of the second annular portion 40 and
a soft, flexible gasket 104 is positioned in the groove, which
gasket will effect suitable sealing contact with the complementary
face surface 44. Should the face surface 44 be eroded to the point
where neither the ribbed gasket surface 50 nor the separate gasket
member 104 is acceptable, the customer may have to machine the face
surface 44 back to its original condition before the spiral adaptor
is assembled thereto.
[0038] Depending on the nature of the mechanical seals with which
the present invention will be used it may become necessary to use a
spiral adaptor in which the bore opens to the seal closer to the
inboard end thereof than in the other embodiments previously
described. Thus there could be one or more intermediate bore
portions between the first and second bore portions. Such spiral
adaptor 110 is illustrated in FIG. 8, where a single intermediate
portion 112 is located between the first portion 114 and the
second, flared portion 116. The intermediate portion 112 is
provided with a spiral groove 118 which leads smoothly into the
spiral groove 120 of the flared bore portion 116. The transition
122 between the first bore portion 114 and the intermediate portion
112 is also flared and includes a spiral groove 124, smoothly
extending the groove 126 of the first portion 114 to the spiral
groove 118 of the intermediate portion. Such an embodiment can be
used with mechanical seal arrangements that are axially long,
including both single and double mechanical seals. The length of
the intermediate portion will be selected to accommodate the
physical parameters of the equipment. If more than one intermediate
portion becomes necessary such could easily be provided with each
such intermediate portion having an increasingly greater diameter
as they lead from the first bore portion to the second bore portion
of the adaptor.
[0039] Turning now to FIG. 9 there is shown an embodiment which can
be used to fill in a seal cavity if it is deemed necessary to do
so, or if the cavity has a deep axial length and only a small first
obstruction space. The first obstruction space is the physical
space that is available for installation of the adaptor when the
equipment is completely assembled. For example, the depth of the
seal cavity might be 5 inches and the physical space between the
end of the seal cavity and the bearing housing of the equipment
might be only 3 inches. If the adaptor is provided in two pieces,
each being 2.5 inches long then one piece can fit easily within the
cavity, in the available 3 inch space for installation. The second
piece can then be installed, for a total length of 5 inches.
[0040] In this embodiment a spiral adaptor 28 as depicted in FIG. 2
is illustrated in conjunction with a cavity insert 130. The insert
130 has an outer circumferential surface 132 sized for a sliding,
tight fit within the cavity, the surface 132 being preferably, but
not essentially, provided with at least two circumferential seal
member-receiving grooves 134. The inner bore 136 of the insert is
provided with a spiral groove 138 having a hand the same as the
direction of rotation of the shaft, which groove will merge
smoothly with the groove 56 found in the first annular portion of
the adaptor 28. With this arrangement particulate material will be
prevented from building up within the seal cavity; as particulate
material enters the seal cavity they are rejected by the spiral
groove 138. The insert 130 will be the first of the pieces
mentioned above, the one that is inserted initially into the cavity
while an adaptor 28 will be the second piece, the one that is
inserted after the first piece to meet the cavity dimensional
requirements.
[0041] FIG. 10 illustrates a spiral adaptor which is especially
adapted for use with an "agitator" type of rotary equipment. An
agitator is a rotary component that has a large blade assembly that
rests inside a larger tank, and rotates to "agitate" or mix the
product within the tank. These tanks are common in the pulp and
paper industry, the tanks being typically filled with a slurry of
paper stock.
[0042] The rotary equipment used to effect agitation is prone to
breakdown. Whenever there is a problem it is necessary to drain the
tank before repairs can be effected to the mechanical seals. By
utilizing the embodiment of FIG. 10 it is possible to avoid having
to empty the tank before repairs can be effected. The spiral
adaptor 140 of FIG. 10 includes all of the standard features as
described with respect to the other embodiments and, in addition,
it is provided with a shutoff mechanism 142 which when activated
will seal itself against the shaft when the shaft has been brought
to a halt. The shutoff mechanism 142 could entail a flexible
sealant ring 144 held within a circumferential groove 145 in the
bore 146 of the adaptor. A radially directed passage or bore 148
would be connected to a source of hydraulic or pneumatic pressure
(not shown) which, when activated would force the ring 144 into
sealing contact with the shaft. When such a shutoff mechanism is
activated with the tank full of product it would not be necessary
to drain the tank in order to effect repairs to the mechanical
seal.
[0043] In some applications the seal cavity might contain packing,
with or without a separate mechanical seal, and it could be
desirable to continue with such a configuration even when utilizing
an externally mountable spiral adaptor of the present invention.
FIGS. 11 and 12 illustrate a situation in which packing can be used
in conjunction with a spiral adaptor especially adapted for use
therewith.
[0044] FIG. 11 shows a shaft 12, shaft housing 14 and a seal cavity
18, much as is shown in FIG. 1. The housing 14 includes a passage
150 for feeding flushing fluid to the seal cavity. An annular
spiral adaptor 152 is positioned deep within the cavity from the
entrance of the cavity and one or more packing rings 154 are forced
into an annular cavity 156 defined between the adaptor 152 and the
shaft 12, as will be seen from FIG. 12, which shows the adaptor in
greater detail. An annular gland plate 157 applies an axial force
against the outermost packing ring to hold the rings in position.
The gland plate 157 is secured to the housing 14 by threaded bolts
158.
[0045] Turning now to FIG. 12, the adaptor 152 is described in
greater detail. The annular body 160 of the adaptor 152 has a first
annular portion 162 having, preferably, an external circumferential
groove 164 for reception of a sealing ring (not shown). The annular
portion 162 has a first bore 166 and a spiral groove 168 therein as
with the other embodiments. A second annular portion 170 has an
outer circumferential groove 172 which communicates with the
passage 150 as well as one or more through bores 174 communicating
the groove 172 with the interior of the adaptor. An outwardly
flaring, spiral grooved section 176 leads from the bore 166 to a
radially inwardly tapering bore section 178, which in turn leads to
a short straight bore section 180, also provided with a spiral
groove 182.
[0046] Outboard of the second annular portion 170 there is an
annular extension 182 which preferably has at least two
circumferential grooves 184 in the outer circumferential surface
thereof, each for reception of a sealing ring (not shown). The
extension 182 has an enlarged bore 186 which extends inwardly
thereof to an annular shoulder 188, against which the innermost of
the packing rings 154 will abut once the adaptor and the packing
have been assembled to the rotary equipment.
[0047] This embodiment is particularly advantageous where there is
a large radial cross-section being used, the adaptor being fittable
externally into the seal cavity. This embodiment will permit the
operator to reduce the diameter of the packing rings being used,
while also permitting more packing rings to be used than otherwise.
For example, in large equipment it would be possible to go from two
rings of 0.750" radial cross-section to three rings of 0.500"
radial cross-section. By being able to use more packing rings, of
smaller radial cross-section, it is possible to reduce the packing
cost without sacrificing sealing efficiency.
[0048] FIGS. 13 and 14 illustrate a variation on the embodiment of
FIGS. 11 and 12. In this embodiment the extension 182 is provided
with a radial flange 190 at the outboard end thereof, which flange
helps to lengthen the extension 182 and thus will allow for the
inclusion of additional packing in the assembly.
[0049] With the new arrangement of externally mounting a spiral
adaptor, and with the adaptors illustrated herein, particulate or
contaminant material around the seal area will be removed or
redirected away from the seal cavity. This arrangement will not
remove particulate material in the seal cavity having a throat
restriction at the bottom thereof. In an open or large bore box,
this would not be a problem because there is no restriction in the
bottom of the seal cavity. It is expected that a skilled person in
the art would be able to modify any of the spiral adaptors
illustrated and described herein to accommodate a particular
application without departing from the spirit of the present
invention. Accordingly the protection to be afforded this invention
is to be determined from the claims appended hereto.
* * * * *