U.S. patent number RE35,824 [Application Number 08/538,040] was granted by the patent office on 1998-06-16 for fluid sample apparatus featuring integral construction with a motor driven sampling system.
This patent grant is currently assigned to Welker Engineering Company. Invention is credited to Brian H. Welker.
United States Patent |
RE35,824 |
Welker |
June 16, 1998 |
Fluid sample apparatus featuring integral construction with a motor
driven sampling system
Abstract
A fluid motor integrally constructed on an elongate body enables
periodic fluid sampling. This device affixes to a pipeline by a
threaded connection which positions an inlet in the pipeline for
sample removal; the sample flows to a sample bite removal valve
which is motor operated to obtain periodic simple bits. Pressure
step up or down is achieved in a sample pressure isolation system
having a check valve function. This enables storage at any
pressure.
Inventors: |
Welker; Brian H. (Sugarland,
TX) |
Assignee: |
Welker Engineering Company
(Sugarland, TX)
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Family
ID: |
26990393 |
Appl.
No.: |
08/538,040 |
Filed: |
October 2, 1995 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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336830 |
Nov 9, 1994 |
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Reissue of: |
418522 |
Oct 10, 1989 |
04928536 |
May 29, 1990 |
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Current U.S.
Class: |
73/863.83 |
Current CPC
Class: |
G01N
1/14 (20130101) |
Current International
Class: |
G01N
1/14 (20060101); G01N 001/14 () |
Field of
Search: |
;73/863.51,863.52,863.81,864.34,863.83 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
Y-Z Industries, Inc., Brite-Rite Model Br-2E, Natural Gas Sampler,
Jan. 15, 1986. .
Y-Z Industries, Inc., "LPR-2 Light Liquid Hydrocarbon Sampler" Nov.
1985. .
Y-Z Industries, Inc., "PNR--2/Probe Mounted Liquid Sample Pump"
(date unknown). .
Tru-Cut Sampler Systems Model "C" Sries (date unknown). .
Y-Z Industries, Inc., "PRN-1 Sampling System" 1981..
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Primary Examiner: Raevis; Robert
Attorney, Agent or Firm: Felsman; Robert A. Perdue; Mark
D.
Parent Case Text
.Iadd.This is a continuation of application Ser. No. 08/336,830,
filed Nov. 9, 1994, now abandoned, which is a Reissue of
07/418,522, now (surrendered) U.S. Pat. No. 4,928,536..Iaddend.
Claims
What is claimed is:
1. An assembly for obtaining a fluid sample from a pressurized
pipeline comprising:
(a) an elongate body having
(i) a first end formed to connect to a pipeline to position a
pressurized fluid inlet .Iadd.probe .Iaddend.in the pipeline to
receive pressurized fluid;
(ii) a central body portion connected to said first end; and
(iii) a second end deployed from said first end;
(b) a fluid flow .Iadd.inlet .Iaddend.line .Iadd.extending through
said elongate body and .Iaddend.connected from said fluid inlet
.Iadd.probe .Iaddend.to deliver a flow of fluid;
(c) fluid sampling means connected to said fluid flow .Iadd.inlet
.Iaddend.line .[.to deliver fluid thereto.]. .Iadd.such that fluid
is delivered to said fluid sampling means .Iaddend.in a volume in
excess of said sample.Iadd., said sampling means periodically
removing fluid from said fluid flow inlet line.Iaddend.;
(d) .[.said sampling means periodically removing fluid from said
fluid flow line;
(e).]. outlet means connected to said sampling means for delivery
of a fluid sample .[.without regard to.]. .Iadd.whether
.Iaddend.the pressure in the pipeline .Iadd.exceeds that in a fluid
sample vessel or the pressure in the fluid sample vessel exceeds
that in the pipeline.Iaddend.;
.[.(f).]. .Iadd.(e) .Iaddend.check valve means cooperative with
said outlet means to enable fluid to flow through said outlet means
to overcome back pressure encountered by fluid flow;
.[.(g).]. .Iadd.(f) said fluid sampling means including a
.Iaddend.rigid .Iadd.sample .Iaddend.chamber connecting means
connecting said .Iadd.fluid .Iaddend.sampl.[.e.]..Iadd.ing
.Iaddend.means and check valve means; and
.[.(h).]. .Iadd.(g) .Iaddend.motor means in said body for operating
said sampling means to direct fluid through said outlet
means.Iadd., said motor means being in fluid communication with the
pipeline through said fluid sampling means, wherein, upon actuation
of said motor means and said fluid sampling means, a fresh sample
of pressurized fluid from the pipeline is taken.Iaddend..
2. The assembly of claim 1 wherein said fluid sampling means
comprises:
(a) .[.sample chamber means for receiving pressurized fluid
therein;
(b).]. a movable plunger sealingly received in said .Iadd.rigid
sample .Iaddend.chamber means;
.[.(c).]. .Iadd.(b) .Iaddend.means connecting said motor means to
said plunger to reciprocate said plunger through a first position
to allow fluid in said chamber means, and reciprocate said plunger
to a second position to force fluid through said check valve means;
and
.[.(d).]. .Iadd.(c) .Iaddend.said motor means forms sufficient
pressure to open said check valve means and also overcome any back
pressure encountered by fluid flow from said outlet means.
3. The assembly of claim 1 wherein said elongate body is formed
by:
(a) a lower end portion having a downwardly extending probe for
insertion into a pipeline, and said probe extends from a threaded
fitting cooperatively connecting to a mating fitting on the
pipeline;
(b) an intermediate portion supporting said outlet means and said
check valve means; and
(c) an upper end portion comprising said second end and supporting
said motor means wherein said upper end portion is joined with and
connected to said intermediate portion to align sad body portions
for joinder in an integrated assembly.
4. The assembly of claim 3 .Iadd.further .Iaddend.including
.Iadd.at least one fluid flow .Iaddend.passage.[.s.]. extending
through .Iadd.each of .Iaddend.said body portions for controlled
fluid flow from said fluid inlet and to said outlet means as
controlled by said fluid sampling means and said check valve means.
.[.5. The assembly of claim 4 wherein said passages include:
(a) an inlet flow passage to said fluid sampling means;
(b) an outlet flow passage from said fluid sampling means for
delivery of surplus fluid not sampled by said sampling means, said
outlet flow passage
having a separate outlet for the surplus fluid..].6. The assembly
of claim .[.5.]. .Iadd.4 .Iaddend.wherein said outlet flow passage
is directed to said lower end body portion and said outlet thereof
returns surplus fluid
into the pipeline. 7. The assembly of claim 3 wherein said motor
means comprises a piston in a cylinder defining a fluid receiving
compression chamber, and said piston is connected to a plunger
moveably positioned in a chamber to reciprocate, said plunger and
chamber comprising said fluid
sampling means. 8. The assembly of claim 1 wherein said fluid
sampling means and said check valve means comprise:
(a) a reciprocating plunger;
(b) a fluid receiving chamber for receiving fluid therein, said
chamber further receiving said plunger to force fluid out of said
chamber;
(c) a passage for pressurized fluid from said chamber;
(d) a valve seat fluidly connected to said passage;
(e) a valve element cooperative with said valve seat to close said
passage to fluid flow; and
(f) spring means bearing against said valve element to provide a
force overcome by fluid pressure on operation of said plunger, said
spring means
otherwise closing said valve element. 9. The assembly of claim 8
wherein
said valve element is a needle valve. 10. The assembly of claim 9
including an additional serially connected supply pressure operated
valve
means closing as a function of pipeline pressure. 11. The assembly
of claim 8 wherein said valve element is a resilient plug larger in
size than
said valve seat and is constructed to fully close off fluid flow.
12. The assembly of claim 11 wherein said resilient plug is
supported in a
surrounding metal ring. 13. The assembly of claim 12 wherein said
ring includes a connected stem mounting said resilient plug for
reciprocation.
.Iadd.14. An assembly for obtaining a fluid sample from a
pressurized pipeline comprising:
(a) an elongate body having
(i) a first end formed to connect to a pipeline to position a
pressurized fluid inlet probe in the pipeline to receive
pressurized fluid;
(ii) a central body portion connected to said first end; and
(iii) a second end deployed generally opposite from said first
end;
(b) a fluid inlet passage extending from said pressurized fluid
inlet probe and through said elongate body to deliver fluid from
said pipeline in a volume in excess of said fluid sample;
(c) fluid sampling means disposed in said elongate body and
defining a rigid sample chamber connected to said fluid inlet
passage to receive fluid from said pipeline through said fluid
inlet passage, said sampling means periodically removing said fluid
sample from said fluid inlet passage;
(d) a fluid outlet disposed in said elongate body and connected to
said rigid sample chamber of said fluid sampling means for periodic
and selective delivery of said fluid sample to a sample storage
vessel;
(e) a first check valve disposed in said elongate body and
cooperative with said fluid sampling means to prevent fluid flow
from said sample storage vessel past said fluid sampling means when
pressure in said sample storage vessel exceeds pressure in said
pipeline;
(f) a second check valve disposed in said outlet and said elongate
body and in fluid communication with said fluid sampling means to
permit said selective and periodic delivery of said fluid sample to
said sample storage vessel when pressure in said pipeline exceeds
pressure in said sample storage vessel, said second check valve
being in fluid communication with said pipeline exclusively through
passages formed in and through said elongate body; and
(g) a motor in said body for operating said sampling means to
direct fluid through said outlet and into the sample storage
vessel..Iaddend..Iadd.15. The assembly of claim 14 wherein said
fluid sampling means comprises:
(a) a movable plunger sealingly received in said rigid sample
chamber;
(b) means connecting said motor to said plunger to reciprocate said
plunger though a first position to allow fluid into said rigid
sample chamber, and reciprocate said plunger to a second position
to force fluid through said second check valve; and
(c) said motor forming sufficient pressure to open said second
check valve and also overcome any back pressure encountered by
fluid flow in said outlet..Iaddend..Iadd.16. The assembly of claim
14 wherein said elongate body is formed by:
(a) a lower end portion having a downwardly extending probe for
insertion into a pipeline, and said probe extends from a threaded
fitting cooperatively connecting to a mating fitting on the
pipeline;
(b) an intermediate portion supporting said outlet and said check
valves; and
(c) an upper end portion comprising said second end and supporting
said motor means wherein said upper end portion is joined with and
connected to said intermediate portion to align said body portions
for joinder in an
integrated assembly..Iaddend..Iadd.17. The assembly of claim 14
wherein said motor comprises a piston in a cylinder defining a
fluid receiving compression chamber, and said piston is connected
to a plunger movably positioned in said rigid sample chamber to
reciprocate, said plunger and rigid sample chamber comprising said
fluid sampling means..Iaddend..Iadd.18. The assembly of claim 14
wherein said fluid sampling means comprises:
(a) a reciprocating plunger;
(b) said rigid sample chamber receiving said plunger to force fluid
out of said chamber;
(c) a passage for pressurized fluid from said rigid sample chamber
to said outlet..Iaddend..Iadd.19. The assembly of claim 18 wherein
said first check valve comprises:
(a) a valve seat fluidly connected to said outlet;
(b) a valve element cooperative with said valve seat to close said
outlet to fluid flow; and
(c) spring means bearing against said valve element to provide a
force overcome by fluid pressure on operation of said plunger, said
spring means otherwise closing said valve
element..Iaddend..Iadd.20. The assembly of
claim 19 wherein said valve element is a needle
valve..Iaddend..Iadd.21. The assembly of claim 14 wherein said
second check valve is a pressure-set check valve in fluid
communication with pipeline pressure through said
fluid flow inlet passage..Iaddend..Iadd.22. The assembly of claim
14 wherein the motor is in fluid communication with the fluid
sampling means and pipeline, wherein fluid from the pipeline acting
upon the motor means passes through the fluid sampling
means..Iaddend.
Description
BACKGROUND OF THE DISCLOSURE
The present apparatus is directed to an integrated construction of
a fluid sampling apparatus and more particularly to one which
incorporates a fluid sampling metering mechanism. It is
particularly adapted for use with flowing fluids in pipelines of
variable pressure. It can be used with a pipeline flow system with
pressures as high as necessary for operation of the pipeline, as
low as might be encountered, and all pressures in between. It is
also intended for use with gases or liquids.
The present inventor has been involved heretofore in various and
sundry high pressure pumps, sample collection devices, and devices
which insert into a pressure vessel including a pipeline. Such
items are exemplified by the following U.S. patents:
3,945,770: HIGH PRESSURE PUMP 4,346,611: INSERTION REGULATOR FOR
PRESSURIZED PIPELINES 4,403,518: SAMPLER APPARATUS 4,440,032:
SAMPLER INCLUDING A PURGE SYSTEM 4,525,127: VANISHNG CHAMBER CRUDE
OIL SAMPLER 4,557,151: SAMPLER INCORPORATING PRESSURE BALANCED
CHECK 4,628,750: INTEGRATED PUMP AND SAMPLE VESSEL
These patents as well at the catalog of products of the corporate
manufacturer of the devices described thereby represent systems
utilized heretofore for obtaining samples from a fluid flow system.
It is the purpose of the present disclosure to set forth a fluid
sampling apparatus which is an integrated structure having
advantages set forth below.
Consider a typical situation involving a fluid flow pipeline which
may fluctuate between 500 and 2,500 psi pressure, the fluctuations
in part arising from variations in demand. Consider the same
situation where the pipeline may deliver natural gas or oil; the
sales price for the fluid will fluctuate depending on BTU content,
CO.sub.2, and other variables. The sample is removed from the
pipeline in proportion to flow. It is removed into a storage
vessel, and that is periodically carried to a laboratory for
testing. The sample must be collected in proportion to the flow and
thus, one part per million or one part per billion may be sampled,
stored and assayed to determine price. In one example, the BTU per
mcf assay is determined and the payment obligations for the natural
gas transaction can then be calculated. The same is also true of
liquid deliveries. In summary, it is important to obtain measured
quantities of sample.
The sample storage container may have an internal pressure which is
greater or less than the pipeline pressure. That pressure can vary
widely also. Another variable of importance is the portion to be
taken to make up the sample. Again, it can vary by perhaps three or
four orders of magnitude.
An important factor in the present disclosure is the ease and the
facility in which an installation can be made. Briefly, such an
installation is often required at remote locations in gas field
gathering lines, or perhaps at an intermediate sized pipeline. Such
locations are remote and difficult to access. It is difficult to
make complex equipment installations in the field. In part, this
relates to the difficulty in drilling into the pipeline and forming
what is known as a hot tap. Even where the connection is made
without the hot tap, it is an expensive undertaking. Cost,
complexity and reliability are substantially impacted by the
present apparatus. It is more readily installed and installed with
a good deal of ease in contrast with the typical system which is
assembled in the field with a multitude of components. The present
apparatus is characterized as an integrated system which can be
attached at a hot tap or alternately in original field installation
before the pipeline is placed in service. In either case, the
installation process is enhanced by use of an integrated system.
Moreover, the integrated system enables fluid flow to be diverted
into the equipment, subjected to control by an off/on valve and
directed into the system for sampling. More sample is taken out of
the pipeline than is required and only a portion thereof is
subsequently stored. In other words, the tapped flow is much larger
than the sample quantity required and so it is further reduced in
volume to match the desired sample output. This is accomplished
with pressure isolation. That is, the sample which is delivered at
pipeline pressure is isolated for storage at the pressure of the
storage vessel. Accordingly, a fluid operated piston with a
connected piston rod received in the cylinder is utilized to take
timed bites from the removed sample flow. The sample bites are
pressure isolated from the pipeline pressure and are delivered to a
sampling valve including a check valve and are then delivered out
of that apparatus at whatever pressure is necessary to be received
in a storage container. Any back pressure encountered is
overcome.
The integrally constructed apparatus incorporates a piston and
connected piston rod cooperative with a sampling valve. All of this
equipment must be properly aligned for installation. By means of
integral construction, field alignment is thereby avoided. Further
by proper alignment, flow passages through the device are provided
so that a small sample flow is derived from the pipeline. The
device includes an integrated off/on valve. There are two
embodiments of the present disclosure and the one is particularly
intended for flowing .[.gases.].. In that embodiment, there are two
off/on valves, one for the sample deliver and the other connected
in the sample return line so that any surplus sample is returned
back to the pipeline.
A .[.liquid.]. embodiment is also set forth. The .[.liquid.].
embodiment incorporates a similar off/on valve. The .[.liquid.].
embodiment is able to remove a .[.liquid.]. sample flow which is
delivered through a sampling valve and is delivered bite by bite to
the sample storage device. The sample storage device is typically a
detachable or removable fixed volume container which lends itself
to easy removal, transportation to a laboratory and subsequent
testing to assay the nature of the sample and to typically obtain
the dollar in accordance with some pricing relationship.
The foregoing is directed to some advantages of the present
invention but more advantages will be noted and understood on
review of the preset disclosure in conjunction with the drawings
set forth below.
BRIEF DESCRIPTION OF THE DRAWINGS
So that the manner in which the above recited features, advantages
and objects of the present invention are attained and can be
understood in detail, more particular description of the invention,
briefly summarized above, may be had by reference to the
embodiments thereof which are illustrated in the appended
drawings.
It is to be noted, however, that the appended drawings illustrate
only typical embodiments of this invention and are therefore not to
be considered limiting of its scope, for the invention may admit to
other equally effective embodiments.
FIGS. 1 and 2 set forth alternate but similar embodiments of the
integrally constructed fluid sampling apparatus of the present
disclosure.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Attention is first directed to FIG. 1 of the drawings which shows
in sectional view a device 10 in accordance with the teachings of
the present disclosure particularly intended for use in liquid flow
sampling and which device is ideally installed in a liquid flow
pipeline. The description will proceed from the bottom, beginning
there to describe the fluid intake and extending through the fluid
sampling apparatus which is shown herein. FIG. 1 therefore shows
the wall of a pipeline at 11 which is provided with an upstanding
circular inlet 12 which is axially hollow and internally threaded
to join to the sampling apparatus 10. The sampling apparatus
incorporates an elongate body made of multiple sections. The
lowermost section is identified at 13 and is constructed with a
threaded lower periphery 14. This fastens to the pipeline and
inserts a liquid inlet opening 15 to a specified depth within the
pipeline to assure delivery of a fluid sample. This is connected to
a passage 16 extending axially through the body 13. The passage 16
connects with a circular valve seat 17, and the seat is closed by a
tapered threaded plug 18 which is a valve element. The plug 18 is
mounted on a stem 19 connected with a handle 20. It is axially
positioned on the interior of a threaded sub 21 which is threaded
to the body 13 and is isolated with a seal ring to prevent leakage
along the threads. The axial passage through the center supports
the stem 19 which is advanced by rotation. On rotation, the stem
positions the valve element 18 in the opening 17 which functions as
a valve seat. In turn, fluid flows from the passage 16 and through
the valve seat 17 into a supply line 22. The supply line is
completely blocked when the valve element 18 is advanced against
the valve seat 17. The valve thus functions as a supply on/off
control. Metering of the flow is obtained by the valve element.
The sampler 10 is constructed of the first body portion 13. A
second body portion 23 is also included. It is an elongate
cylindrical body portion having passages drilled therein as will be
described, and this body portion extends to and connects with the
next body portion 24. In turn, the several body portions are held
together so that there is no leakage. They are preferably
fabricated with parallel faces, the end faces being joined with
appropriate seals. Moreover, a flange 25 extends radially outwardly
from the body portion 24 and suitable bolts 26 thread through the
flange 25 and into the portion 13. This captures the cylindrical
body portion 23 therebetween and applies pressure to the seals.
Assuming the valve 18 is in the open position, fluid flows through
the supply passage 22 and then to a tee 27. One leg of the tee is
through the fitting 28, line 29 and a control valve 30. The line 29
extends to the upper end of the sampler 10 and is used in a fluid
motor to be described. The tee 27 is defined by positioning an
insert 33 within the body 24, the body 24 being substantially
hollow. The insert 33 is positioned internally against a
registration shoulder 34 and is provided with internal and external
seals to prevent leakage around the outer surface thereof. The
insert 33 has an internal fluid receiving chamber 35 which is a
sample receiving chamber. It connects with the tee 27 by means of
the port 36. The port 36 is an inlet port through the insert 33 to
the chamber 35, and there is additionally an outlet port 38 which
is symmetrically constructed through the insert 33. A plunger 40
extends into the chamber 35 and is sized to pass through the
chamber 35 and to sealingly engage a seal member 41 held in
position by the insert 33. The plunger reciprocates downwardly,
forcing fluid into a passage 42, the fluid flowing through the
passage 42 when the plunger moves. Fluid in the passage 42 is
trapped. It is a specified bite of fluid which is sized by the
dimensions of the passage 42. The passage 42 is axially
communicated with an enlarged chamber 45 which receives a
cylindrical insert 46. The insert 46 functions as a spring cage to
position a compressed coil spring 47 bearing against a valve
element 48. The valve element 48 is constructed with a central
resilient plug. That plug seats against the valve seat 49 formed at
the lower end of a telescoping insert 50. The insert 50 nests
within the cage 46 to position the valve seat 49 in operating
relationship to the insert 48. Moreover, the insert 50 is hollow,
delivering fluid from the passage 42 through the valve seat. With
the valve 48 against the seat, no flow occurs. Flow occurs when the
pressure bearing against the valve element 48 is sufficient to
force the valve open against the force of the spring 47. Moreover,
fluid which flows past the valve then is delivered to a fluid
outlet passage 51 through appropriate fittings 52 and a conduit 53
for delivery of fluid to a remote sample storage container.
Returning to the plunger 40, it will be observed that the plunger
isolates a certain portion of liquid for delivery through the
passage 42. A portion of the liquid does not flow into the passage.
Rather, the sample which is delivered through the sample supply
line 22 is directed through the insert by flowing first into the
passage 36 and out through the passage 38. Flow through the passage
38 is delivered to a surplus fluid line 56 extending downwardly in
FIG. 1. This fluid flows to an outlet valve which is defined by a
valve element 57 operatively positioned opposite a valve seat 58.
The valve element 57 is mounted on a threaded stem 59 having a
handle 60 for opening and closing of the valve. Moreover, fluid is
delivered into a return passage 61 for return into the
pipeline.
The fluid flow paths include the following routes. All fluid that
is introduced into the sampler 10 flows upwardly through the
passage 16. As will be understood the direction of flow in the
pipeline is from left to right as viewed in FIG. 1 and the shape of
the inlet 15 directs fluid upwardly into the passage 16. The
equipment can be switched off by closure of the valve handle 20. It
is, however, normally switched on by opening the valve by rotation
of the handle 20. This separates the valve element 18 from the
valve seat 17 and permits fluid to flow upwardly through the
passage 22. This passage extends upwardly to the tee 27 and
delivers fluid into the passage 42. When the plunger 40 is in the
up position, fluid will flow through the tee 27 and out through the
passage 38. The surplus fluid passage then delivers the surplus
fluid through the return control valve operated by the handle 60.
Surplus fluid is delivered through the line 61 back into the
pipeline.
The spring 47 is selected and sized so that its spring force
exceeds the pressure experienced at the valve element 48. Thus, the
valve element is a check valve which is closed at all times except
on operation of the plunger 40. Thus, if pipeline pressure is 2,000
psi, then the spring 47 is sized so that the check valve does not
open at this pressure to deliver a sample out of the system. The
spring is sized to require a greater pressure for closure. On the
other hand, when the plunger 40 reciprocates downwardly to raise
pressure in the passage 42, the plunger 40 force raises the
pressure sufficiently that the check valve is overcome, and fluid
is delivered to the sample outlet means 53. This conveys the outlet
fluid downstream to the sample collection apparatus. Moreover, the
sample collection apparatus may have substantial pressure and hence
create back pressure at the outlet means which must be overcome.
Whether the back pressure is high or low, the plunger 40 has a
stroke of sufficient length below the seal 41 to force a specified
volume of sample out of the sample flow and deliver it into the
sample collection apparatus notwithstanding any back pressure
encountered.
Consider the relative size of the sample relative to the fluid
flow. For a particular pipeline operating pressure, pipeline
diameter, and liquid velocity through the pipeline, liquid is
delivered at a specified rate. By sizing the inlet opening 15
relative to the pipeline and positioning it at a specified depth in
the pipeline, fluid is delivered into the sample inlet line 22 in a
specified ratio relative to pipeline flow. This ratio can be some
arbitrary value such as one unit per 10,000 units of flow. That
sample is delivered past the plunger 40 which periodically takes a
bite. The bite which is removed is sized relative to the flow
moving past the plunger 40. The flow fills the passage 42 prior to
operation of the plunger 40. When the plunger enters the seal 41
and closes off that chamber, a specified volume of sample is
forcibly displaced by plunger movement. That volume is forced
through the check valve and into the sample storage apparatus. This
is a specified ratio dependent in part on the flow rate of sample
moving past the plunger 40, the size of the chamber 42, the length
of the plunger stroke, and other appropriate scale factors. It is
desirable to have a fixed sampling rate such that the sample
actually removed and delivered to the storage container in one part
per 100 units, or as much as one part per 10,000 units. Again, this
is a scale factor and it can be controlled by changing the size of
the plunger 40, changing the length of plunger stroke, and also by
changing the frequency or interval at which the plunger is
operated. In any event, that ratio is implemented, and for purposes
of description, assume that it is one unit of sample for 1,000
units of flow through the sampling mechanism 10. The plunger thus
removes a portion for subsequent testing. Since only a portion of
the flow is taken by the inlet means 15 and the sampling valve
means 40 takes only a portion, the two ratios are multiplied
together to obtain a sampling ratio. The sampling ratio can be
anywhere between 10.sup.5 to about 10.sup.9. These are
representative scale factors which can be implemented by scaling
the equipment in the fashion described. Moreover, this ratio
preferably is established at the time of installation of the
present apparatus or in the event of subsequent change in the
nature of the product being sampled. In that instance, it may be
necessary to change sizes of components. For instance, the spring
47 might be changed in size. The plunger stroke can be adjusted
also. Alternately, frequency of operation by the controller 30 can
be implemented.
Continuing with the description of FIG. 1, the upper end of the
sampler incorporates a cylinder attachment 63. It encloses a piston
64 which is connected to the plunger 40. The piston 64 is a single
acting piston, and it is returned to its initial position by means
of a return spring 65. The return spring 65 is seated on a shoulder
counter bored into the cylinder attachment. The piston defines a
fluid receiving chamber 65 which is on the top side of the piston.
Moreover, the top end of the equipment is closed by a cylinder head
66 which threads to the cylinder attachment 63 and thereby defines
the chamber 65. Fluid which is delved into the chamber 65 is also
vented back through the feedline and is controllably disposed of by
the controller 30. Venting is accomplished by controller 30
shutting off flow from line 29 and then venting the fluid in the
line and chamber 65 to the atmosphere or other low pressure
area.
The system utilizes pipeline pressure which is delivered to the top
of the piston 64. This large area piston assures that the force
applied to the plunger 40 is sufficient to overcome the spring 65
and to compress the liquid captured by the plunger during
operation. Moreover, the plunger is driven downwardly by a
specified stroke. Thus assures that the plunger takes a consistent
and equal sized bite during operation. It forces captured liquid
out of the passage 42 past the check valve in the quantity
determined by the diameter of the plunger 40 and the length of its
stroke past the seal 41.
DETAILED DESCRIPTION OF THE GAS EMBODIMENT
Going now to FIG. 2 of the drawings, an alternate embodiment is
illustrated in sectional vie. The numeral 70 identifies an
alternate structure which is constructed for handling gaseous
products, typically natural gas, and which is constructed in
similar fashion to the structure shown in FIG. 1. A substantial
portion of the description remains the same. Accordingly, the lower
portion 13 again is identified by the same reference numeral as
before. It is joined to a cylindrical portion 23 thereabove of
similar construction. The structure includes the same flow inlet at
15 which is delivered to a similar valve seat 17 cooperating with a
similar valve element 18 which is stem supported by a similar stem
19 and which is opened and closed by a similar handle 20. This
apparatus has been illustrated at the right side of FIG. 2, but it
will be appreciated that it is structurally the same as the
structure shown on the left of FIG. 1. For clarity in the drawings,
it is illustrated on the right so that the flow line 22 is shown in
a less obscure position. In like fashion, the sampler 70 includes
the intermediate body portion 24 which again is joined by the bolts
26 extending through the flange 25 thereabove. The fluid flow is
delivered for compression by a similar plunger 40. That is, the
inlet from the pipeline is through the passage 22 and that is
directed through the port 36 and out through the port 38. These
ports again are shown on opposite sides of the drawing but they are
identical to those shown in FIG. 1. Fluid for operation of the
fluid motor is delivered through the supply line 29 and the timed
controller 30 is again illustrated for timed operation of the fluid
motor in the sampler 70.
The plunger 40 again pumps downwardly through a seal 41 which
encircles the plunger and thereby defines a downwardly extending a
passage or chamber 42. That terminates at .[.a.]. .Iadd.rigid
.Iaddend.relatively narrow passage 71 which opens to a valve seat
72 defined by a resilient O-ring. There is a tapered needle valve
element 73 positioned against the seat. It incorporates a needle
valve tip for guidance, and it is forced open by gas flow against
the valve element 73. The needle valve is urged to a closed
position by resilient spring 74. The spring is captured below a
spring mechanism, this mechanism including a surrounding insert 75,
a captured orifice fitting 76, and suitable seals to prevent
leakage around these components. Gas flows from the chamber 42
through the small orifice 71. It flows through the needle valve and
past the needle valve. It flows through a small orifice passage 77
drilled in the orifice fitting 76. It is delivered through the
bottom of this passage and out that opening. However, fluid is not
permitted to flow because there is a pressure set check valve to be
overcome. This pressure set check valve is made dependent on line
pressure. Specifically, line pressure is introduced from the supply
passage 22 through a lateral line 78, and below a plunger 79. The
plunger 79 supports a plug 80 which blocks flow out through the
passage 77. The plug 80 is smaller than the passage and hence, any
gas flow escaping that contact flows downwardly and into the port
81 when contact between plug 80 and fitting 76 is broken. The port
81 includes the appropriate fittings 82 and connects through the
outlet line 83 to a sample storage container. The plunger 79 is
forced upwardly by a bias spring 84 which is of sufficient strength
to force the plug 80 upwardly. However, plug movement is controlled
primarily by the cross-sectional area of the plunger 79 and
pressure which is exposed to it. Representative pressure levels
will be given hereinafter.
Consider a typical situation in operation. Assume that the sampler
70 is installed on a natural gas line at 1,000 psi. Fluid flows
from left to right as viewed in FIG. 2. The inlet means 15 draws in
fluid flow, and it flows into the inlet passage 22 assuming the
valve handle 20 has been operated to open the valve 18. This fluid
flows to the plunger 40. It is captured in the passage 42 when the
plunger is operated downwardly. Surplus fluid is delivered away
from the plunger. One outlet is through the line 29 which flows to
the timed controller 30 which times application of fluid to the
fluid motor at the top end which operates in the same fashion as
shown in FIG. 1 of the drawings. That is, the plunger 40 is driven
downwardly by the piston, and compression of the captured gas
occurs in the passage 42. .Iadd.As can be seen in FIG. 2, fluid or
gas from the pipeline and rigid sample chamber 42 is employed
(through passage 38, line 29, and controller 30) to actuate plunger
40, and the volume of gas sampled after actuation of plunger 40 is
fresher or more representative of that flowing in the pipeline at
the time of the sample. .Iaddend.
The gas is compressed, forced downwardly, and the flows past the
needle valve. It flows into the small passage 77 through the
orifice insert 76. When this pressure is sufficiently high, it will
force the plug 80 slightly downwardly so that gas flows around the
plug 80. Gas flows through the outlet port or passage 81 into the
fitting 82 and through the line 83 for delivery to the sample
storage chamber which is not shown. The gas so stored is recovered
for sample testing purposes.
Consider representative pressures which might occur in the sampler
70. The passage 78 is provided with gas at line pressure or 1,000
psi in this example. It is applied below the plunger 79. The
plunger 79 has a ratio of area to the plug 80 of about 2:1 and
provides multiplication of approximately two fold in that event.
That is, gas samples delivered through the passage 77 must exceed
approximately two fold line pressure. In other words, the plug 80
will not open until pressure bearing against it at the top end is
in excess of about 2,000 psi in this example. Gas flows upwardly
through the supply passage 22 and is delivered into the chamber 42.
When the plunger 40 moves downwardly into the seal 41, pressure
rises in the chamber 42. This pressure rise is observed therebelow
in the passage 77. When that pressure becomes sufficient, the plug
80 is forced backwardly, opening slightly and gas flows into the
port 81. Fluid then flows while exceeding this representative
pressure. That is, the gas that is delivered through the outlet
line 83 is compressed to a sufficient pressure that is forces open
the tapered needle valve 73, and also flows past the plug 80.
Assume that the storage container for the sample is maintained at a
pressure which is low. In that event, the sample is simply
delivered in regular fashion into that storage vessel. If however,
the back pressure of the storage vessel is much greater than the
line pressure, that does not pose any problem either. Sample cannot
escape back into the equipment because there is a check valve at
the valve 73. Accordingly, the pressure on the compressible gas is
raised sufficiently high that it will overcome practically any back
pressure at the storage container. Moreover, pressure is isolated
between strokes so that the storage container does not bleed
through the sampling valve just described.
Consider proportioning of the present apparatus. Sample again is
captured in the range of about one part in 10.sup.5 up to about one
part in 10.sup.9. Obviously, these are subject to scale factors and
can be varied to a desired output sampling rate.
The samplers 10 and 70 utilize the same basic structural
components. They both terminate at a remote end which incorporates
a fluid motor. In both instances, the motor is preferably single
acting with a return spring. That is, fluid pressure from the
pipeline is used to drive the piston. This avoids the necessity of
providing a remote fluid supply at a remote location. Just as
importantly, pipeline pressure is not a limitation on the operation
of the fluid motor because it is provided with greater
cross-sectional area so that even a low pipeline pressure system
can provide sample against a high back pressure storage device.
While the foregoing is directed to the preferred embodiment, the
scope thereof is determined by the claims which follow:
* * * * *