U.S. patent application number 15/427903 was filed with the patent office on 2017-08-10 for cryogenic pump and inlet header.
The applicant listed for this patent is Trican Well Service Ltd.. Invention is credited to Floyd GUEST, Donald R. LUFT, Ben MIKULSKI.
Application Number | 20170227002 15/427903 |
Document ID | / |
Family ID | 59497486 |
Filed Date | 2017-08-10 |
United States Patent
Application |
20170227002 |
Kind Code |
A1 |
MIKULSKI; Ben ; et
al. |
August 10, 2017 |
CRYOGENIC PUMP AND INLET HEADER
Abstract
A header and a pump end for a cryogenic pump are provided for
efficient liquid pumping operation. The header directs supplied
liquid into a sump and gas into a freeboard. The liquid in the
header can be distributed along the header and decanted over a weir
to the sump, the liquid being drawn from the sump and up through
the vessel to the pump end. Gas in the freeboard is collected for
venting or return to the liquid source. Pump head plunger stroke
can be lengthened and operated at slower stroke rates using a large
cross-sectional area intake and discharge valves. Plunger seals,
supported as a seal pack in a sleeve, are field installable over
the plunger. A plunger to drive shim arrangement permits filed
adjustment of the stroke.
Inventors: |
MIKULSKI; Ben; (Ladysmith,
CA) ; GUEST; Floyd; (Bashaw, CA) ; LUFT;
Donald R.; (Calgary, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Trican Well Service Ltd. |
Calgary |
|
CA |
|
|
Family ID: |
59497486 |
Appl. No.: |
15/427903 |
Filed: |
February 8, 2017 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
62292792 |
Feb 8, 2016 |
|
|
|
62427005 |
Nov 28, 2016 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F04B 9/045 20130101;
F04B 53/16 20130101; F04B 2015/081 20130101; F04B 53/109 20130101;
F04B 37/08 20130101; F04B 23/00 20130101; F04B 2015/0824 20130101;
F04B 15/08 20130101; F04B 53/1075 20130101; F04B 53/143 20130101;
F04B 53/162 20130101 |
International
Class: |
F04B 53/10 20060101
F04B053/10; F04B 53/14 20060101 F04B053/14; F04B 53/16 20060101
F04B053/16; F04B 15/08 20060101 F04B015/08 |
Claims
1. An intake header for a cryogenic pump having one or more pump
heads comprising: a generally horizontally extending vessel having
a liquid sump and a gas freeboard; a liquid intake to the vessel
and connected to a source of cryogenic liquid; a gas outlet
connected to the freeboard for venting gas ; and one or more
conduits, each conduit forming a suction corresponding to the one
or more pump heads, each suction extending from the sump to a
respective pump head for delivery of liquid in the sump to the pump
head.
2. The header of claim 1 wherein two or more of the one or more
suctions are spaced horizontally along the vessel for corresponding
to the one or more pump heads
3. The header of claim 1 wherein each suction extends upwardly from
the sump, through the liquid in the sump, through the gas in the
freeboard and through an upper wall of the vessel for connection to
the pump head.
4. The header of claim 1 further comprising a gas header along the
upper wall of the vessel and in fluid communication with the
freeboard for collecting gas therefrom.
5. The header of claim 1 wherein the vessel is cylindrical and
having a horizontal axis, the liquid inlet being located at one end
of the vessel at about the axis thereof.
6. The header of claim 1 further comprising a generally
horizontally extending baffle in the sump.
7. The header of claim 6 wherein the baffle is a tray dividing the
sump into an upper liquid-receiving portion above and a lower
desaturated liquid portion therebelow, the tray having a weir for
spilling liquid from the upper portion to the lower portion.
8. The header of claim 1 further comprising a distributor extending
along the vessel for receiving liquid from the intake and having a
plurality of openings for distributing the liquid along the
horizontal extent of the vessel.
9. The header of claim 1 further comprising a generally
horizontally extending tray dividing the sump into an upper
liquid-receiving portion above and a lower desaturated liquid
portion therebelow, the tray having a weir for spilling liquid from
the upper portion to the lower portion; a distributor extending
along the vessel for receiving liquid from the intake and having a
plurality of openings for distributing the liquid along the
horizontal extent of the vessel, the distributor extending along
the tray in the upper portion, the opening being located within the
liquid in the upper portion.
10. A pump head for a cryogenic pump having a cylinder, a cylinder
head, and a plunger axially slidable in the cylinder for forming a
chamber of variable axial extent between the cylinder head and the
plunger, comprising: a liquid inlet to the chamber; a discharge
outlet through the cylinder head and having a discharge valve; and
an intake valve comprising a plurality of inlet passages spaced
circumferentially-spaced about the cylinder head and situate
between the liquid inlet and a periphery of the chamber, and a
ring-plate movable axially relative to the cylinder head between an
open position away from the cylinder head for receiving liquid
through the inlet passages to the chamber and a closed position
engaged sealingly against the cylinder head to close the inlet
passages.
11. The pump head of claim 10 wherein the cylinder head further
comprises a cylindrical body having an annular valve seat formed
thereabout for sealingly engaging the ring-plate in the closed
position, the inlet passages formed about the valve seat.
12. The pump head of claim 10 wherein the cylinder head further
comprises an annular inlet port about an outer circumference of the
cylinder head, the annular inlet port in fluid communication with
the liquid intake for distributing liquid about the cylinder head
to the inlet passages.
13. The pump head of claim 10 further comprising a spring for
biasing the ring-plate to the closed position.
14. The pump head of claim 10 wherein the cylinder head has a
generally concave face, the plunger having a complementary
protruding convex piston end face.
15. The pump head of claim 10 wherein the pump's cylinder comprises
a cylindrical sleeve supported within a pump housing, the
cylindrical sleeve and cylinder head retained axially within the
pump housing.
16. The pump head of claim 15 wherein the pump housing has the
liquid inlet formed therethrough, the annular Inlet port of the
cylinder head being axially aligned with the fluid intake for
receiving liquid from the liquid inlet.
17. The pump head of claim 10 wherein the pump's cylinder comprises
a cylindrical sleeve supported within a pump housing, the
cylindrical sleeve and cylinder head retained axially within the
pump housing, further comprising a valve assembly, the valve
assembly comprising the intake and discharge valves.
18. The pump head of claim 17 wherein the valve assembly is
supported in the pump housing, aligned axially with the plunger,
comprising: the cylinder head, having a cylindrical body co-axially
aligned with the plunger and having an annular valve seat formed
thereabout, the ring-plate located in the chamber between the
plunger and the cylinder head and movable axially towards the
annular valve seat in the closed position for blocking the inlet
passages and directing liquid to the discharge valve and axially
away for the intake of fluid into the chamber, the discharge valve
comprising a plunger arranged within the discharge outlet through
the cylinder head and forming an annular passage thereabout, the
plunger supported in the discharge outlet and slidable between open
and closed positions; and a retaining nut to axially retain the
valve assembly within the pump housing.
19. The pump head of claim 17 wherein the valve assembly further
comprises: a discharge cover between the retaining nut and the
cylinder head, the discharge cover comprising an annular plate
having a plurality of circumferentially spaced discharge passages
formed therein and in fluid communication with the annular passage
of the discharge valve.
20. The pump head of claim 19 wherein the discharge cover further
comprises a boss for slidably supporting the plunger in the
discharge outlet.
21. The pump head of claim 10 wherein the plunger has a piston end
operable in the chamber and a tail end adapted for connection to a
drive, the tail end, the plunger supported for reciprocation in a
pump housing further comprising: a cylindrical sleeve supported
within the pump housing for forming the cylinder and having the
piston end slidable therein; and a seal assembly supported within
the pump housing, the plunger's tail end sealably slidable
therein.
22. The pump head of claim 21 wherein the plunger has a piston end
operable in the chamber and a tail end adapted for connection to a
drive, the tail end, the plunger supported for reciprocation in a
pump housing further comprising: a cylindrical sleeve retained
axially within the pump housing for forming the cylinder and having
the piston end slidable therein; and a seal assembly retained
axially within the pump housing, the plunger's tail end sealably
slidable therein.
23. The pump head of claim 22 wherein the seal assembly comprises:
a seal pack for slidably sealing the tail end of the plunger; a
sleeve replaceably retained axially within the pump housing, the
sleeve having a first lip for supporting the seal pack for axial
removal from the pump housing; and a packing nut for axially
retaining the sleeve and retained seal pack within the pump
housing.
24. The pump head of claim 10 wherein a tail end of the plunger is
releaseably connected to a drive, further comprising one or more
ring shims between the tail end of the plunger and the drive for
adjusting a spacing of the plunger from the cylinder head.
25. A sealing assembly for cryogenic pump, the pump having a
cylinder and a cylinder head supported in a pump housing, and a
plunger axially slidable in the cylinder for forming a chamber of
variable axial extent between the cylinder head and a piston end of
the plunger, the sealing assembly between a tail end of the plunger
and the pump housing, the sealing assembly comprising: a sleeve
replaceably retained axially within the pump housing and having a
plunger bore therethrough for receiving the tail end of the
plunger, the sleeve having a inboard lip and an open outboard end,
the sleeve being axially removable from the pump housing; an
annular seal pack fit through the outboard end into the plunger
bore and supported axially at the inboard lip, the seal pack
sealing between the seal pack and the sleeve and between the seal
pack and the plunger; and a packing nut for axially releasably
retaining the seal pack to the sleeve and the outboard end of the
sleeve to the pump housing.
26. The sealing assembly of claim 25 wherein the seal pack
comprises: a first rod seal adjacent the inboard lip; a stack of
lip seals; a spacer between the first rod seal and stack of lip
seals.
27. The sealing assembly of claim 26 wherein the first rod seal
comprises a ring seal carrier supporting a compressor and a rod
seal, the compressor and rod seal having complementary wedges for
driving the rod seal radially inwardly and sealably against the
plunger.
28. A cryogenic pump comprising the pump head of claim 10 and the
header of claim 1.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. Provisional Patent
Application No. 62/292,792. filed Feb. 8, 2016, and to U.S.
Provisional Patent Application No. 62/427,005, filed Nov. 28, 2016,
the entirety of both of which are incorporated herein by
reference.
FIELD
[0002] In embodiments, a liquid inlet and pump head for a cryogenic
pumper are provided, the header having a sump, a return conduit for
unused liquid to a liquid source, and a freeboard for gas removal,
the pump head having long stroke, low speed plunger and low back
pressure valve assembly.
BACKGROUND
[0003] In many industries, including the oil and gas industry,
liquefied gases are vaporized to a gaseous form for a variety of
high volumetric operations including use of vaporized nitrogen
liquid for delivery to subterranean destinations for downhole
stimulation. Nitrogen gas is one type of inert gas that can be used
to reduce the hydrostatic pressure exerted by stimulation fluids.
This minimizes the amount of fluid pumped into formation and
enables rapid clean-up in low pressure reservoirs. Further, as a
non-reactive gas, nitrogen can be used in a variety of ways to
support pipelines and industrial facilities, including:
displacement, inerting otherwise potentially flammable spaces,
helium leak testing, pneumatic testing, purging, freeze plugs,
accelerated cooling, blanketing, catalyst handling support, hot
stripping and heating.
[0004] Liquid nitrogen is supplied in liquid form, in a cryogenic
state. Stimulation often occurs at high pressures in the order of
10,000 to 15,000 psi. The nitrogen is pressurized to the high
pressures using specialized cryogenic pumping equipment. For the
rates and pressure, multiple positive displacement pumps are used,
arranged in parallel.
[0005] Liquid nitrogen, at very low temperatures is provided to a
header at the inlet of the gang of pump heads at a pumper. The
liquid enters each pump head suction at a cold end, and is
displaced from a displacement chamber by a pressure stroke of
reciprocating plunger of the pump head to discharge through a pump
outlet at high pressure. The plunger returns and draws more liquid
into the displacement chamber to repeat the cycle. The associated
drop in suction pressure upon drawing fluid into the displacement
chamber can alter the liquid properties and degrade pump
performance, even to the point of eventual damage to the pumping
components. Further recirculation of un-used liquid during a
pumping cycle is returned to the source. The circulation and
warming of the recirculating liquid can result in the entrainment
of air with the liquid nitrogen.
[0006] Some of the symptoms of pump distress include cavitation,
fluid knock or hammer, suction end vibration, reduced plunger life
and catastrophic failures in the power end including plunger
connecting rods, crankshafts and related fasteners and seals. Pump
distress and failures are exacerbated by high stroke rates.
[0007] While the industry has been focused on net positive suction
head (NPSH) of the liquid delivered to the suction, poor quality of
a liquefied gas delivered to the pump head is a further factor
exacerbating poor pump behaviour and failure.
[0008] Other areas of frustration for the field operator, pump
heads can suffer short mean times between failures (MTBF) and
repairs are typically performed in a shop environment, requiring
frequent transport of each failed pump head or pump offsite.
[0009] There is a desire for reduced incidences of pump repair,
extended MTBF, a field repair capabilities when a failure does
occur.
SUMMARY
[0010] Herein, Applicant provides a manifold or header to the
suction of one or more cryogenic liquid pump heads. The manifold
provides suction stabilization, and thermal maintenance of the cold
end of a cryogenic pump. For simplicity, the apparatus and
methodology is described in the context of providing liquefied
nitrogen for the oil and gas industry although the apparatus and
processes described herein are equally applicable to the pumping of
other liquids handled in both cryogenic liquid and vaporized
gaseous forms.
[0011] Further, in instances of entrained gas, the manifold can
also aid in gas desaturation of the liquid nitrogen provided to the
nitrogen pumper. Applicant has determined that the liquid
circulated between the source of liquid gas and the cryogenic pump
heads can entrain gas such as air or evolve N2 gas. N2 gas
evolution is exacerbated by warming of the conveyed cryogenic
liquids. Handling of the liquid, including transfer through piping
and vessels can result in the incorporation of gas during transport
or evolution of gas within the liquid, resulting in a gassy liquid.
Gassy liquids, and the release of gas therefrom under pressure
reduction, including pump suction conditions and flow
irregularities, increase the handling difficulty and risk of damage
for the form of positive-displacement or other pumps used in this
area.
[0012] Herein, for convenience, the gassy liquids are referred to
as gas-saturated liquid regardless of the extent of saturation. The
extent of gas removal, using embodiments described herein, is
referred to qualitatively as moving from a saturated to a
desaturated state even through the liquid may not be fully
saturated, nor gas free respectively.
[0013] In one aspect, a manifold or intake header is provided
having a vessel comprising liquid storage belly portion in a lower
portion of the vessel, and a gas freeboard at a top of the vessel.
Provision of a gas freeboard with a liquid sump in the belly
portion aids gas separation from the liquid destined for the pump
suction. A recirculation line removes excess liquid such as from a
mid-vessel liquid port or from an optional launder after an
overflow weir.
[0014] The belly portion includes a sump from which a substantially
gas-free liquid is collected or stored and then drawn from for
delivery to the pump inlet. The freeboard portion is a gas cap
above the liquid sump for collection and subsequent removal of any
gas released from the liquid stored for pump intake. The removed
gas can be vented or recirculated to the cryogenic liquid
supply.
[0015] In one embodiment, the liquid supplied to the header is
separated into liquid pooled in the belly portion and any gas
released from the liquid collects in the freeboard. Gas is removed
from the freeboard leaving a desaturated liquid in a sump of the
belly portion. Desaturated liquid intended for the pump suction, is
drawn from deep within the liquid sump. In an embodiment, the
liquid is delivered along the vessel through a distributor, the
distributor releasing supplied liquid upwardly into the header for
encouraging gas release to the gas freeboard, and said release
further occurring within the level of the belly portion to minimize
gas portion re-entrainment with the incoming liquid.
[0016] In an embodiment, the liquid supplied to the vessel is
decanted or overflows a tray weir and collects in a sump portion of
the belly portion. The desaturated liquid overflows the weir,
intended for the pump suction, and is drawn the liquid sump.
[0017] In an embodiment, liquid removal by each pump suction is
through a conduit extending downward through the vessel, through
the freeboard and into the liquid stored in the belly portion, to
access the sump. The sump provides a consistent liquid storage for
control of the NPSH and supply of substantially gas-free liquid
under the normal pumping conditions. The liquid removal conduit,
immersed in the cold liquid, maintains the low temperature delivery
of liquid to the pump head.
[0018] As noted by Applicant, the described intake manifold or
header provides a constant, desaturated liquid flow to the cold
ends of the pump heads. The intake header separates and eliminates
flow of gas-saturated liquid to the pump heads and the operational
problems associated therewith. Further, the sump and liquid suction
design, including routing through the interior of the header
itself, aids in maintaining cold temperatures of the suction
conduit and conveyed liquid to the heads. Any unused, oversupply of
desaturated liquid is recirculated back to the liquid source
tank.
[0019] All cryogenic plunger pumps benefit from desaturation of
entrained air or other gas from the liquid through the design of
the intake manifold.
[0020] Broadly, an intake header for a high pressure displacement
pump head comprises a horizontal vessel having a liquid storage
belly portion, a gas freeboard and a mid-vessel liquid input. One
or more suctions extend from the belly portion to a suction of its
respective pump head. In embodiments, the conduit forming each
suction extends upwardly from the sump, internal to the vessel, and
exits through an upper wall of the vessel for connection to its
respective pump head cold end. Gas exit ports are formed along the
upper wall of the vessel and collected in a gas header.
[0021] In one embodiment, a tray divides the belly portion into an
upper liquid receiving portion and a desaturated liquid sump
therebelow. The tray extends from one end of the vessel for receipt
of gas-saturated liquid, distribution horizontally along the header
vessel, for separation of gas and for liquid. The gas reports to a
freeboard and liquid decants from the tray for delivery of
desaturated liquid to the sump.
[0022] In another aspect, Applicant has determined that pump head
cold end performance is improved sufficiently to permit longer
stroke operation with reduced incorporated gas-related problems
resulting in maintenance of comparable volumetric liquid pumping
performance at lower pump stroke rates. Lower stroke rates results
in lower stress on pump components and longer MTBF.
[0023] In another aspect, valve design further improves cold end
performance. The implementation of a large cross-sectional liquid
inlet area results in a low pressure drop and minimizes
gas-release, cavitation and other reduced pressure liquid effects.
Such valve design also results in pump head configuration having
longer stroke operation for comparable volumetric performance at
lower pump stroke rates.
[0024] In another aspect seal arrangements result in reliable pump
plunger sealing and ease of field installation and replacement, as
a retrofit or as a provided sealing arrangements
[0025] In combination, both a desaturated liquid supply header and
improved valve components, embodiments of both of which are
provided herein, result in a reliable, long lasting cryogenic pump
head.
[0026] Further, in other aspects, embodiments of the pump head
design enable field installation and repair including plunger
stroke adjustment on assembly and plunger seal repair onsite.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] FIG. 1 is a process flow diagram of a manifold or intake
header according to one embodiment;
[0028] FIG. 2A is a perspective drawing of an embodiment of the
intake header to the heads of a Quintuplex pump;
[0029] FIG. 2B is a perspective drawing of the embodiment of FIG.
2A with the outer wall of the vessel and the collection header
rendered transparent;
[0030] FIG. 3A is a perspective schematic view of a header
illustrating the liquid supply to the header belly portion, a gas
freeboard, liquid flow from the sump to each pump head, and liquid
recirculation;
[0031] FIG. 4A is an end cross-sectional view according to FIG.
3A;
[0032] FIG. 3B is a perspective transverse cross-sectional view of
a header illustrating a liquid supply distributor and suction
conduit extending from the sump to one of the pump heads;
[0033] FIG. 4B is an end cross-sectional view according to FIG.
3B;
[0034] FIG. 3C is a perspective transverse cross-sectional view of
the header of FIG. 2B, illustrating a section through a suction
conduit of one of the five pump heads;
[0035] FIG. 4C is an end cross-sectional view according to FIG.
3C;
[0036] FIG. 5 is a side view of the intake header of FIG. 2B, with
the internals shown in hidden lines;
[0037] FIG. 6 is an end view of the intake header of FIG. 5 with
the internals shown in hidden lines;
[0038] FIGS. 7A-7C illustrate various individual components of the
intake header;
[0039] FIG. 8A shows a partial cross-sectional side view of a
triplex pump according to the prior art;
[0040] FIG. 8B is a perspective view of a side cross-section of a
pump head illustrating the pump cylinder and pump plunger valve,
seals and pony rod connection. The pump inlet is shown as usual on
the bottom of the pump cylinder;
[0041] FIGS. 9A and 9B are perspective views of the pump head of
FIG. 8B, with the pump cylinder (FIG. 9A) illustrated separately
from the internal components (FIG. 9B);
[0042] FIG. 10A is a side cross-sectional view of the pump head of
FIG. 8B with a first embodiment of the field installable plunger
seals;
[0043] FIG. 10B is a side cross-sectional view of the pump head of
FIG. 8B with an alternate embodiment of the field installable
plunger seals and with the pony rod coupling shown removed, the
clamp 132 shown installed in solid lines and apart in dotted
lines;
[0044] FIG. 10C is a close-up side cross-sectional view of the
packing sleeve and seals of FIG. 10A;
[0045] FIG. 10D is a close-up side cross-sectional view of the
packing sleeve and seal of FIG. 10B;
[0046] FIGS. 11A and 11B illustrate the valve in operation, more
particularly illustrating the beginning of the liquid intake stoke
(FIG. 11A), and the liquid discharge stroke (FIG. 11B);
[0047] FIG. 12 is an exploded view of the valve illustrating the
flow passages, seals and springs;
[0048] FIG. 13 is a transverse cross-section of the cylinder and
plunger to illustrate the splined internal cylinder sleeve;
[0049] FIG. 14 is a transverse cross-section of the cylinder and
plunger to illustrate the cross-flow ports at the end of the
internal cylinder sleeve;
[0050] FIGS. 15A and 15B are perspective ends view of the drive end
of the pump head and illustrating the plunger end and plunger clamp
apart (FIG. 15A) and assembled (FIG. 15B); and
[0051] FIGS. 16A and 16B are side cross-sectional views of the
drive end of the pump head and illustrating the plunger and pony
rod interface with shims added to adjust the plunger's piston head
closer to the valve (FIG. 16A) and shims removed to adjust the
plunger's piston head further from the valve (FIG. 16B), the shims
permitting field adjustment of the pump head and drive.
DESCRIPTION
[0052] With reference to FIG. 1 a schematic illustrates an
embodiment of an intake header coupled between one or more high
pressure cryogenic pump heads and a source of cryogenic liquid.
Herein, the treatment and handling of the cryogenic liquid is
described in the context of providing liquefied nitrogen for
pressurization and then vaporization in the field of fracking and
hydraulic lift operations. Thus, while the description refers to
Nitrogen (N2), in liquid and gaseous forms, the apparatus and
processes described herein are equally applicable to other liquids
capable of handling in both liquid and gaseous forms.
[0053] A charge pump 10, such as a centrifugal pump, delivers a
liquid supply LS from a liquid source, such as a N2 tank 12 to an
embodiment of the pump header 20. Gas G separates from the liquid
LS and is directed back to the source or tank 12. Liquid LP is
delivered to the cold end of each pump head 22 and pressurized
liquid LV is directed to a vaporizer 24 for producing high pressure
gas to the process.
[0054] In a first embodiment, a header 20 for one or more cryogenic
pump heads 22 is provided.
[0055] With reference to FIGS. 2A and 2B, 5 and 6 the header 20
comprises vessel 30 having a liquid intake 32 for receiving liquid
nitrogen from the source, such as cryogenic tank 12. The vessel 30
is cylindrical and is oriented generally horizontally. In an
embodiment, the intake 32 is coupled to a distributor 34 (FIG. 2B)
extending generally horizontally along vessel 30 for delivery of
liquid along the length of the vessel 20.
[0056] The intake 32 is located at about the axis of the vessel 30
with discharge of the supplied liquid upwardly thereto. In
embodiments, the intake 32 is located in the liquid stored in the
vessel.
[0057] Liquid intended for the pumper, is drawn from a sump 38 of a
belly portion 40 of the vessel 30. A freeboard portion 44 above the
liquid in the belly portion 40 receives any gas released from the
liquid or otherwise accompanying the liquid into the vessel. Liquid
collects in the belly portion, the level of which can be controlled
including by intake-discharge control, or pressure control of the
gas collected in the freeboard.
[0058] A plurality of pump suctions 36,36,36 . . . are spaced along
the length of the vessel 30. To minimize disruption to the liquid
supply to the pump, each pump head has its own pump suction 36
between the pump's cold end and the sump 38. A portion of the pump
suction 36 is also physically located in the vessel, from a suction
inlet 42 located in the sump 38, passing upwardly through the cold
liquid stored in the belly portion, and passing upwardly through a
freeboard portion 44 above the liquid for exit from the vessel. The
suction inlet 38 is immersed in the liquid in the vessel and
remains cold, to minimize thermal disruption to the liquid directed
to its respective pump head.
[0059] The horizontal distributor 34 delivers the liquid supply LS
along the length of the vessel 30, such as through discharge of the
liquid through a plurality of discharge a holes 47. The holes 47,
such as circular or slots, can be located along an upper wall of
the distributor 34 for aiding in gas/liquid separation; gas
separating upwardly to the freeboard, and de-saturated liquid
downwardly to the sump 38.
[0060] The length of the vessel and distributor 34 is dependent
upon the number of pump heads 22 for the pump, the spacing between
pumps heads 22 dictating the spacing of pump suctions 36 and the
length of the header vessel necessary to accommodate the number of
pump suctions 36. A vessel suitable for a Quintuplex pump (5 pump
heads) is shown, a shorter vessel could be employed for a single
pump and common triplex pumps (3 pump heads) as appropriate.
[0061] As shown in FIGS. 3A and 4A, the vessel separates liquid and
gas, the gas G reporting to the freeboard portion 44 and liquid L
reporting to the belly portion 40. The liquid supply LS is provided
to the midpoint of the vessel. G gas separates from the liquid L
and liquid LP for the pump heads 22 is drawn from the sump 38. Gas
GV, for venting or return to the liquid supply 12 is withdrawn from
the freeboard portion 44. Liquid L is typically provided in excess
of the amount of liquid LP used by the pump heads and therefore a
recirculation liquid LR is return to the liquid supply 12.
[0062] As shown in FIGS. 3B and 4B, a portion of the vessel 30
incorporating two horizontally spaced pump suctions 36,36 is shown.
The distributor 34 is shown extending along the axis of the vessel
30. Liquid supply LS from the source 12, is discharged to the
vessel interior, such as through holes 47. A liquid interface or
level LL is formed.
[0063] A port 46 for recirculation of excess liquid LR is provided
at a distal end of the horizontal distributor 34. At a top of the
vessel 30, a chamber 48 is provided for the collection of gas G.
One or more gas outlets 50 are provided for the controlled removal
of collected gas. Equilibrium between gas arriving with the liquid
supply LS, and gas removed from the vessel, can be controlled,
including through a sized orifice, or needle valve, or large
capacity valve fit with a bleed orifice. A large capacity valve at
gas outlet 50, when opened, permits a large capacity, cold liquid,
recirculation for startup, and when closed permits a small bleed
flow of gas therethrough to maintain a liquid gas interface in the
vessel. While the provision of freeboard 44 provides a chamber for
collection of separated gas G, separation can be further aided by
low pressure drop release of gas from the distributor, such as
through generously sized holes 47, and by releasing the liquid
supply beneath the interface or liquid level LL.
[0064] As shown in FIGS. 3C and 4C, in this additional embodiment,
the length of the vessel 30 can also fit with a generally
transverse extending baffle for forming an upper liquid storage
thereabove, a still sump 38 below and liquid communication
therebetween. One form of baffle can be an internal tray 60.
Saturated or partially saturated liquid supply LS containing some
gases, spills from the distributor 34 into the tray 60. At least
some gas G separates from the liquid LS and rises to the upper,
liquid-free volume of the freeboard 44.
[0065] The liquid LS, which can still be partially saturated, flows
into the upper liquid receiving portion of the tray 60 and collects
until steady-state operations in which the liquid level LL reaches
a tray level TL, all the while being provided with an opportunity
to release gas, after which the liquid spills over a weir portion
62 of the tray and into the lower desaturated liquid sump 38 in the
lower volume of the belly portion 40.
[0066] Gas G in the freeboard 44 is collected in the chamber 48
along an upper wall of the vessel 30 for return to the source tank.
As stated, the gas outlet 50 can be controlled to meter the gas
exiting the vessel, controlling the liquid level LL. Other known
liquid level controllers can be employed.
[0067] As above, the de-saturated liquid LP intended for the
pumper, is drawn from the sump 38. To minimize disruption to the
liquid supply to each pump head 22, each pump head has its own
suction 36. Each suction 36 is a conduit also physically located in
the vessel, having liquid inlet 42 immersed in the liquid of the
sump 38, the conduit of the suction passing through the freeboard
44 and through the upper wall of the vessel 30 for connection to
the cold end of the pump head 22. The suction 36 and a large
portion of the conduit forming the suction, in this embodiment
being greater than half the length, is immersed in the liquid of
the sump and remains cold, minimizing thermal disruption to the
liquid directed to its respective pump head.
[0068] The tray 60 is shaped, in cross-section as a letter
"J"-shape or eaves-trough shape, having a raised tip or spillover
weir 62 at a lower end. The generally vertical portion 64 of the
upper stem of the "J"-shape separates the gas/liquid separation
volume of the freeboard from the conduit of the pump suction 36
rising from the sump 38 to exit the vessel 30. One or more portals
66 in the upper wall of the vessel permit gas therein to be
collected in the discharge header or chamber 48.
EXAMPLE
[0069] A vessel about 3.5 feet long and 8 inches in diameter can
process 150 USgpm for supplying a triplex pump (three (3) pump
heads 22 and corresponding suctions 36) and 300 USgpm for a
quintuplex pump (five (5) pump heads 22 and corresponding suctions
36). The saturated liquid enters via a 2 inch (Sch 40) pipe as a
distributor 34 with a plurality of exit holes 47 formed along the
wall along the top, in this embodiment twenty-eight (28) holes are
shown, each about 0.375 inches in diameter. Gas exits through
openings 66 along the top of the 8 inch vessel. For integrity, the
openings are spaced apart with vessel structure therebetween,
formed as several (three) 1.75'' wide slots, each 10 inches long,
aligned end to end. Each suction 36 is 1.25'' (Sch 40) is a pipe
with a 90 elbow as an inlet 42. The gas chamber 48 can be a 2''
(Sch 40) pipe cut longitudinally along its axis for forming a
half-pipe to sealably cover the openings 66.
[0070] Pump Head
[0071] The cryogenic pump 22 contemplated herein is a plunger-type
pump having a reciprocating plunger. One pump of a prior art
triplex pump is shown in FIG. 8A, the figure drawn from issued U.S.
Pat. No. 8,543,245 B2 issued 2013-09-24 to Halliburton. As shown a
conventional arrangement is a pump head 90 having a plunger 91 that
alternately draws liquid through a one way intake valve 92 into a
pump chamber 94 and then pushes the liquid out of the chamber
through a one way discharge valve 95. The chamber 94, plunger 91,
valves 92,95 and seals 96 for the plunger are part of the pump head
90, otherwise known as a cold end. The plunger 91 is driven in a
reciprocating manner by a crankshaft 97 and drive arrangement
98.
[0072] In the case of the cold end, conventional problems with
volumetric pumping capacity and reliability are usually related to
the inflow and outflow of liquid nitrogen on the return stroke of
the plunger. Flow restrictions, resulting in high dP across both
intake and discharge, can result in one or more of flashing of gas
from the liquid and cavitation, resulting in damage to the
components. Conventionally, pump stroke is limited to minimize such
phenomenon and lessen damage associated therewith. A limitation on
plunger stroke and pumping stroke rate limits pump capacity.
[0073] Herein, the axial length of the stroke of the plunger has
been significantly increased without degradation of the fluid
handling performance. Indeed fluid handling is improved. Applicant
has directed the improvement in design to mechanical reliability
and ease maintenance rather than increasing pump output. Industry
output rates are maintained while reducing the stress on the pump
components.
[0074] In an embodiment, Applicant has adapted having about three
times the stroke length which results in three times the volume of
fluid per stoke. Accordingly, given a design flow rate, one can
pump the same flow rate as the prior pumps at one third (1/3) the
stroke speed.
[0075] The reduced stroke speed of the reciprocation of the plunger
results in multiple improvements in mechanical component life. The
conventional pump comprises a drive including a motor and a gear
box, a crank, a piston or pony rod and a piston plunger, the
plunger reciprocating in the pump head. Seals are located between
the moving plunger and a cylinder head and also within one-way or
check valves to regulate liquid intake to the cylinder chamber.
[0076] Reduction of the speed of the plunger results in reduced
wear on seals and the check valve. Heat generated by the
reciprocating plunger and seal friction is reduced. Forces are
reduced on the piston rod connections, the gear box and the
motor.
[0077] Herein, additional improvements include an improved liquid
inlet and discharge head, and improved seals. The seals are both
simpler and shorter. The plunger and cylinder are longer and better
supported for co-axial alignment.
[0078] Further, various improvements are possible to aid in field
maintenance including ease of installation and seal and head
repair. During installation, the head needs to be aligned with the
plunger to minimize seal misalignment and wear resulting therefrom.
Further, the connection between the piston and the pony rod needs
to be carefully set to avoid bottoming out the end of the piston
and the head whilst ensuring maximal pump performance.
[0079] Further, after some time, seals will wear and require
repair. Here prior art seals need to be repaired in a shop setting,
herein a seal cartridge or sleeve is provided that can be replaced
in the field.
[0080] In more detail and with reference to FIG. 8B, pump head 100
supports a cylinder such as a cylinder sleeve 102 supported in a
pump housing 104 and having a pump plunger 106. The plunger 106 is
slidable within the sleeve 102 for alternately increasing and
decreasing the pump chamber 108 within. The plunger 106 is has a
piston end 110 that reciprocates in the cylinder sleeve 102. The
cylinder head 112 is a cylindrical body arranged axially opposing
the piston end 110. The piston end 110 is reciprocated away from a
cylinder head 112 to create a suction in the chamber 108 so as to
draw new liquid into the chamber 108 through an intake valve 116.
The piston end 110 is reciprocated towards the cylinder head 112 to
compress liquid in the chamber 108 against a cylinder head 112 and
discharge liquid through a discharge valve 114.
[0081] The piston end 110 is fit with a rider ring 120 and seals
122 for sealing the plunger's piston end 110 to the cylinder sleeve
102. The plunger 106 is cylindrical, and is sealable in a tubular
surround, the piston end 110 sealable in a cylindrical cylinder
sleeve 102 and the balance of the plunger sealable in a cylindrical
bore of the pump housing 104. Annular seals 124 are fit about the
plunger 106 at a tail or connection end 126 opposing the piston end
110.
[0082] The plunger 106 is removably connected at the connection end
126 to a pony rod (not shown) that is driven back and forth along a
plunger axis by a connection rod and crank arrangement. The pump
housing 104 is secured to a skid or other structure, securing the
housing 104 at a flange 128. The flange 128 is secured to a fixed
frame which is dimensionally set or also fixed dimensionally for
locational stability relative to the connecting rod and crank
arrangement.
[0083] As shown, the pump housing has an inlet 117 for the receipt
of cryogenic liquid FP. The inlet 117 is shown as usual and
conventional, located on the bottom of the pump housing 104. Liquid
can be provided by a header, such as that used in conventional
ganged cryogenic pumps, or a header as set forth in FIGS. 1 through
7C.
[0084] From the valve end, the internal components comprise a valve
assembly 130 comprising the intake valve 116 and the discharge
valve 114. The intake valve 116 receives liquid through the liquid
inlet 117 and the discharge valve 114 discharges liquid through
discharge outlet 115. The cylinder housing 104 supports the
cylinder sleeve 102 within which the piston end 110 reciprocates.
The piston end 110 is the leading end of the plunger 106 adjacent
the cylinder head. The tail end 126 of the plunger 106 extends
sealingly through the seal packing 124 for coupling to a pony rod
end (not shown) by a rod end clamp 132.
[0085] Note that while other drawings may be oriented with the
liquid inlet 117 as oriented upwards, this is merely an artifact of
the computer generated drawings.
[0086] FIGS. 9A and 9B illustrate the cylinder housing 104 in
isolation and internal components for housing therein respectively.
From a discharge end of the cylinder housing 104, an installation
bore 105 is provided for axially receiving the cylinder sleeve 102
and valves 114,116. From the tail end 126, the housing 104
comprises a packing bore 107 for receiving a seal assembly
including the seal packing 124.
[0087] FIG. 10A is a side cross-sectional view of the internals
according to FIG. 9B and having a first embodiment of a field
installable seal assembly including the plunger seals 124. The
seals 124 are housed in a packing sleeve 140. The packing sleeve
has a plunger bore for receiving the plunger 106 therethrough. When
the pony rod-to-plunger clamp 132 is removed, a packing nut 142 can
be removed and the entire packing seal sleeve 140 and contained
seals 124 can be removed for replacement.
[0088] The packing sleeve 140 has a first proximal shoulder or
inboard lip 150 at an inboard end and a distal shoulder 144 at an
outboard end. The inboard lip 150 axially supports the seal pack
124 firstly as a stop for enabling axial retention of the seal pack
124 therein and as a pull structure enabling removal of the seal
pack 124 as a complete set of otherwise individual seals, the
sleeve 140 and seals 124 removable over the tail end 126 of the
plunger 106. The proximal lip 150 of the packing sleeve 140 is
sealed, such as at an O-ring 146, for sealing the sleeve 140 to the
pump housing 104. The opposing or outboard end of the sleeve 140 is
open for axially receiving the seals 124.
[0089] FIG. 10B is a side cross-sectional view of the field
installable plunger seals and according to a second embodiment
having a reduced number of seal components and hence being a less
expensive seal. The seal sleeve 140 and packing 124 can be of the
same length as that of FIG. 10A, such as for ease of retrofitting a
seal of the first embodiment with a seal of the second embodiment.
Alternatively, as shown, the seal sleeve 140 and packing 124 can be
axially shorter, such as by incorporating a fewer number of hat or
lip seals. A shorter seal can resulting in a shorter pump housing
when engineered in combination.
[0090] With reference to FIG. 10C, in greater detail, and
illustrated from left to right, the inboard lip 150 of the sleeve
140 is shoulder 150 having opposing shoulder faces, one inboard
face against the pump housing 104 and the other outboard face
against the seal pack 124.
[0091] The seal pack 124 of FIGS. 10A and 10B comprises a first
seal adjacent the inboard end, a stack of lip seals adjacent the
outboard end, and a spacer therebetween. The entire seal pack is
axially retained to the sleeve 140 and the sleeve is retained to
the housing 104. The first seal, is axially compressible by the
balance of the seal pack 124 to actuate a radial energizing profile
such as a wedge to drive the seal against the plunger 106.
[0092] The first seal can comprise a first ring seal carrier 152 at
the proximal end adjacent the outboard face of the inboard lip 150.
The ring seal carrier 152 supports a rod seal 158 that is axially
compressible to actuate a radial energizing profile to drive the
rod seal 158 into sealing engagement with the plunger 106. The
carrier 152 forms an annular space to the plunger 106 for
supporting a ring seal compressor 156 axially slidable therein and
a spring 157, such as a Belleville washer, for energizing the
structure of the compressor 156 relative to a carrier shoulder
150b. The carrier shoulder 150b is sealably supported at the
sleeve's inboard shoulder 150. Compressor 156 has a ramp or wedge
corresponding to a matching wedge on the rod seal 158 for driving
the rod seal 158 radially inwardly and sealably against the plunger
106.
[0093] Next is a lantern ring 160 spacing the rod seal 158 from a
series of hat seals assemblies 162,162 . . .
[0094] Six hat seal assemblies are shown, each seal assembly 162
comprising an annular seal spacer 164 having a generally square or
slightly trapezoidal cross section, and a hat seal 166 itself
having a generally "L" shape supported over the seal spacer/spacer
164.
[0095] All of the ring carrier 152, lantern ring 160 and hat seal
assemblies 162 are supported in the plunger bore forming a packer
sleeve annulus. Axial extraction of the packer seal sleeve 140, and
support by the sleeve shoulder inboard lip 150, pulls all of the
seal components from the cylinder housing 104.
[0096] The packer seal sleeve 140 is releasably retained to the
cylinder housing 104 using a packer nut 170. The nut 170 has a
narrow annular shoulder 172 that engages a hat ring O-ring seal 176
that engages the packing seals 124. The seals are compressed
axially, for increasing the radial sealing capability. The axially
engaged seals press on the seal sleeve shoulder, retaining the
assembly to the cylinder housing 104. The nut can include a rider
ring 179 for axial alignment with the plunger 106.
[0097] FIG. 10D is a close-up side cross-sectional view of the
alternate packing sleeve and seal of FIG. 10B. The sleeve and seal
are shown removed from the plunger. Again, from left to right, the
sleeve and seal comprise from the sleeve shoulder 150: a rider ring
180 instead of a ring seal carrier and seals, an extended length
lantern ring 182 and a diminished number of hat or lip seal
assemblies 162. The lantern ring 182 can be as long as needed to
space the seal assemblies 162 from the rider ring 180 and, in some
embodiments, to match the previous length of the first seal
assembly for retrofit applications, or shortened so as the entire
sleeve and seal assembly can be shortened.
[0098] FIGS. 11A and 11B illustrate the intake and discharge valves
116,114 in operation. FIG. 12 illustrates the valve assembly 130 in
exploded view illustrating various flow passages, seals and
springs.
[0099] In greater detail, the valve assembly 130 is supported in
the cylinder housing 104 at the piston end 110 of the plunger 106.
The cylinder sleeve 102 is first installed axially into the
installation bore 105, and then the valve assembly 130, forming the
liquid pumping end of the pump head 100. From the piston end 110
(right side, moving left), the cylinder sleeve 102 has a valve end
190 which axially supports and seal the cylinder head 112 thereto.
The valve end 190 has a stepped bore for forming an annular sealing
shoulder 191 for sealably and supportably receiving the cylinder
head 112, between the liquid inlet and the chamber 108. The valve
end's stepped bore further forms a smaller diameter within the
sealing shoulder 191 for forming the pump chamber 108. The chamber
108, of variable axial extent, is formed between the piston end 110
of the plunger 106 and the cylinder head 112.
[0100] The intake valve 116 is operable against and works in
combination with a piston face of the cylinder head 112.
[0101] The body of the cylinder head 112 has a plurality of intake
ports therein, arranged about the annular periphery of the cylinder
head to access a radial periphery of the chamber, the intake ports
being alternately opened and blocked by a ring-plate of the intake
valve 116. The plurality of intake ports are arranged and spaced
circumferentially about an annular valve seat on the face of the
cylinder head. The valve seat of the cylinder head 112 is fit with
a plurality of circumferentially-spaced inlet passages forming the
intake ports 192 to the chamber 108. The intake ports 192 are
located between the fluid inlet and the chamber 108 for fluid
communication therealong. The intake valve 116 comprises a
ring-plate 194 biased against, and to close, valve seat having the
inlet ports 192 therein. The ring-plate is an annular ring having a
bore through which the piston end 100 can reciprocate. The
complementary annular faces of the cylinder head 112 at the ports
192 and the ring-plate 194 seal when engaged.
[0102] Radially within the annular valve seat, the face of the
cylinder head 112 is concave or dished, having a truncated, right
conical recessed portion therein and a face of the piston end 110
can also have a complementary convex truncated, right conical
protruding portion. The dished and protruding portions are
complementary to minimize the chamber volume on the discharge
stroke.
[0103] A coil spring 196 is fit operably between a shoulder the
stepped bore of the cylinder sleeve piston end 190 and the
ring-plate 194. The ring-plate is operable axially between open and
closed positions. The ring-plate 194 is movable axially against the
biasing of the spring 196 to move away from and open the ports 192
as the piston end reciprocates away from an intake valve seat the
cylinder head 112. The ring-plate 194 is movable axially with the
biasing of the spring 196 to move towards the cylinder head 112 to
close the ports 192 as the piston end reciprocates towards from the
cylinder head 112. The interface of the intake valve seat of the
cylinder head 112 and ring-plate is a sealing interface, shown as a
finished and complementary metal-to-metal surface.
[0104] The stepped shoulder of the cylinder sleeve can include an
annular and axially extending recess as an axial stop and to retain
the coil spring 196 about its periphery.
[0105] An annular inlet port 199 about the outer circumference of
the body of the cylinder head fluidly communicates with the inlet
ports 192. The annular inlet port aligns axially with the liquid
inlet 117 in the cylinder housing 104 and distributes liquid
received from the header about the annular inlet port for access to
the intake ports 192.
[0106] The intake ports 192 are distributed and spaced
circumferentially about the intake valve 116 and provide
significant cross-sectional area for minimal restriction to the
incoming flow from the liquid inlet 117. Minimal pressure drop
minimizes gas evolution. Liquid provided to the annulus inlet port
is distributed thereabout to each port.
[0107] The cylinder head 112 also supports the discharge valve 114
retained in the installation bore 105 in the cylinder housing 104.
The discharge valve 114 is a one way valve having a valve plunger
200 biased by spring 202 closed against an annular valve seat 204
in the downstream side of the cylinder head 112. In this embodiment
the plunger 200 is arranged along the axis of the valve assembly.
The plunger has a valve face and a shaft 201 supporting the valve
plunger 200 for axial movement between open and closed positions.
An annular discharge passage 203 is formed axially through the
cylinder head 112 and about the plunger 200 and is in fluid
communication with the discharge port 115 through a discharge cover
206.
[0108] The discharge cover 206 is an annular plate having a
plurality of circumferentially spaced discharge passages 208 formed
therein, also comprises a boss 209 and a bushing 211, located along
the axis, for slidably supporting the plunger's shaft 201. The
discharge cover 206 receives liquid flowing from the annular
discharge passage 203 of the discharge valve 114 and discharges
same to the discharge outlet 115. A discharge valve retainer 210,
having a discharge bore forming the outlet 115 therein, concludes
the functional valve components. The discharge valve retainer 210
retains the discharge cover 206 against the cylinder head 112.
[0109] Downstream from the discharge valve retainer 210, a
retaining ring nut 212, with wrench ports 214 arranged
circumferentially thereabout, threadably engages the cylinder
housing 104 to retain the valve components 114,116 and a distal end
220 of the cylinder sleeve 102 axially against a main shoulder 222
of the cylinder housing 104 (FIGS. 9A,9B). The retaining nut 212
engages a wear ring 216 sized to the installation bore, extending
all along the installation bore 105 to the main shoulder 222.
[0110] Fit to the installation bore 105 are the wear ring 216 and
the discharge valve retainer 210, with an O-ring 230 sandwiched
therebetween. The discharge valve retainer 210 engages the ported
discharge cover 206, having a copper ring seal 232 sandwiched
therebetween. The ported discharge cover 21--supports the boss 209
and coil spring 202 for guiding and biasing the discharge valve
plunger 200 upstream against valve seat 204. The ported discharge
cover 206 engages the cylinder head 112, having a copper ring seal
234 sandwiched therebetween.
[0111] An outside diameter of the cylinder head 112 engages the
cylinder sleeve 190 and drives the sleeve against the housing's
main shoulder. Annularly within the cylinder head end of the
cylinder sleeve is an annular suction valve chamber. The suction
valve, having an annular ring valve, is biased downstream to seal
the inlet passages. The spring is sandwiched between the annular
ring valve and annular chamber wall at the cylinder sleeve.
[0112] As shown in FIG. 11A, on the liquid intake stroke, the
piston end 110 moves away from the cylinder head 112 and a low
pressure results in the pump chamber 108. The annular ring-plate
194 pulls away from the circumferentially spaced inlet passages,
against the spring bias. The one way discharge valve is securely
retained in the closed position by the large differential pressure
between the discharge and the pump chamber. Thus liquid flows from
about the annular inlet port 198, through the inlet ports 192,
physically displacing the annular ring-plate 194 axially to fill
the piston chamber 108.
[0113] As shown in FIG. 11B, on the liquid discharge stroke, the
piston end 110 is craven towards the cylinder head 112 for generate
a high pressure in the pump chamber 108. The annular ring-plate 194
is biased closed against the cylinder head 112 to avoid any
backflow and pressure differential ensures it stays closed against
the circumferentially spaced inlet ports 192. The plunger 200 of
the one way discharge valve 114 is forced open, off of valve seat
204, against the small biasing of the coil spring 202 and liquid
flows around the valve plunger 200 and out the discharge ports 208
of the discharge cover. The liquid flows through the bore of the
discharge valve retainer 210 and out the pump outlet 115.
[0114] The cylinder sleeve 102 is provided with cooling
circulation. FIG. 13 is a transverse cross-section of the cylinder
housing 104 and plunger 106 to illustrate an externally-splined
internal cylinder sleeve 102. The cylinder sleeve 102 firstly
provides a piston barrel or complementary cylindrical surface 240
for receiving the piston end 110. The piston end 110 is sealably
and slidable thereon. Secondly, the cylinder sleeve has an external
surface 242, upon which is formed one or more axially-extending
splines 244 forming passages 246 therebetween. The sleeve 102 is
fluid cooled by the flow of liquid through the passages 246 and
therealong.
[0115] As shown in FIGS. 8B, 9B, 13 and 14 a first annular cooling
passage 248 is located circumferentially about the cylinder sleeve
102 and about the piston end adjacent the cylinder head 112. The
axial passages 246 are fluidly connected to the annular cooling
passage 248 end and extend axially back toward shoulder 222. As
also shown in FIG. 8B, a circulation port 250 is provided at the
shoulder 222, for fluid communication with a second annular cooling
passage 252 and axial passages 246. The circulation port 250
fluidly connected at the distal end of the cylinder sleeve 102. The
second annular cooling passage 252 is fit with radial cross ports
254 through the sleeve 102 and in fluid communication with a
backside chamber 256 of the piston end 110. FIG. 14 illustrates the
cross-flow ports 254 at the distal end of the internal cylinder
sleeve 102.
[0116] FIG. 15A and 15B are perspective ends view of the drive end
of the pump head 100 and illustrating the tail or connection end
126 of the plunger 106 and plunger clamp 132. In FIG. 15A, the
clamp 132 is illustrate split apart for disconnecting the plunger
106 from the pony rod 260 (See FIG. 16A), and in FIG. 15B is shown
assembled for connecting the components drivably together.
[0117] Turning to FIGS. 16A and 16B, cross-sectional views of the
plunger 106 and pony rod 260 connection of FIG. 15A illustrate
field adjustment of the plunger's axial position, to adjust the top
dead center (TDC) to the plunger's piston end 110 closer and
further from the cylinder head 112. The stroke and axial position
of the pony rod 260 is set by the motor, gear box, crank and
connecting rod position on a pumper. Once installed in the field,
the TDC can be adjusted.
[0118] In FIG. 16A, one or more ring shims 261 are added to the end
of the pony rod 260 to space the plunger's tail end 126 a distance
h further from the pony rod 260, in turn locating in the piston end
110 closer to the cylinder head 112. Ring shims 261 can be removed
to draw the plunger closer to the pony rod 260, in turn spacing the
piston end 110 a clearance c further from the cylinder head
112.
[0119] The tail end and the pony rod are fit with beveled ends
262,264 respectively, the bevelled ends being complementary with
internal annular beveled surfaces 272,274 of the clamp 132. The end
of the pony rod is fit with an insert 280 having the bevelled end
264 formed thereon. The insert 280 has a shaft portion 282 and a
larger upset end 284 bearing the beveled end 264. The ring shims
261 are located about the shaft portion 282 and axially between the
upset end 284 and the pony rod. The insert 280 is secured to the
pony rod 260 with a cap screw 288 or other suitable fastener.
[0120] A face 300 of the insert 280 of the pony rod 206 engages a
302 face the tail end 126 of the plunger 106. Thus, the relative
axial position of the piston end 110 and pony rod 206 are set.
Removing one or more ring shims 261 causes the plunger 106 to be
secured by the clamp 132 closer to the drive end, with the piston
end 110 further from the cylinder head 112. Thus, onsite
maintenance and adjustments can be performed by adding and removal
of shims to adjust the plunger's piston end 110 closer and further
from the cylinder had and valve assembly 130.
* * * * *