U.S. patent application number 15/971485 was filed with the patent office on 2018-09-06 for compact ultrahigh pressure dynamic seal assembly with pressure activating backup ring.
The applicant listed for this patent is Hypertherm, Inc.. Invention is credited to Eric J. Chalmers, Jon W. Lindsay, David Osterhouse, Arion Vandergon, Cedar J. Vandergon.
Application Number | 20180252210 15/971485 |
Document ID | / |
Family ID | 52697561 |
Filed Date | 2018-09-06 |
United States Patent
Application |
20180252210 |
Kind Code |
A1 |
Osterhouse; David ; et
al. |
September 6, 2018 |
Compact Ultrahigh Pressure Dynamic Seal Assembly With Pressure
Activating Backup Ring
Abstract
The invention features a seal assembly for a high pressure
liquid system. The seal assembly includes a seal carrier having a
base portion defining a proximal end, a distal end, and a bore. The
seal carrier also includes a seal disposed within the bore of the
seal carrier. The seal carrier also includes a backup ring disposed
within the bore of the seal carrier. The seal carrier also includes
a hoop ring disposed substantially between the seal and the backup
ring, the hoop ring having a proximal surface and an outer
surface.
Inventors: |
Osterhouse; David;
(Minneapolis, MN) ; Chalmers; Eric J.;
(Minneapolis, MN) ; Lindsay; Jon W.; (Grantham,
NH) ; Vandergon; Arion; (St. Louis Park, MN) ;
Vandergon; Cedar J.; (New Brighton, MN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Hypertherm, Inc. |
Hanover |
NH |
US |
|
|
Family ID: |
52697561 |
Appl. No.: |
15/971485 |
Filed: |
May 4, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14641822 |
Mar 9, 2015 |
9989054 |
|
|
15971485 |
|
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61949798 |
Mar 7, 2014 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F16J 15/56 20130101;
F16J 15/164 20130101; F16J 15/181 20130101; F16J 15/166 20130101;
Y10T 29/49297 20150115; F04B 53/164 20130101 |
International
Class: |
F04B 53/16 20060101
F04B053/16; F16J 15/56 20060101 F16J015/56; F16J 15/16 20060101
F16J015/16; F16J 15/18 20060101 F16J015/18 |
Claims
1. A seal component for a seal assembly of a high pressure liquid
system, the seal component comprising: a body defining a
substantially cylindrical aperture, the body including a first
axial surface defining an outer diameter, a second axial surface
defining an inner diameter, a third surface for engaging at least
one of a press fit plug or a seal carrier, and a fourth surface for
engaging at least one of a seal or a hoop ring when exposed to a
pressure load, wherein at least a portion of the second
circumferential surface is angled relative to a vertical plane.
2. The seal component of claim 1 wherein the seal component is a
backup ring.
3. The seal component of claim 1 wherein the fourth surface is
angled radially outward.
4. The seal component of claim 1 wherein the fourth surface is
angled between about two and about ten degrees.
5. A method of locating a seal and a seal component in a seal
assembly having a base portion defining a proximal end and a distal
end, the method comprising: inserting, through an opening in the
proximal end of the seal assembly, the seal into the seal assembly;
placing, through the opening in the proximal end of the seal
assembly, the seal component in contact with the seal within the
seal assembly; and securing the seal and the seal component in the
seal assembly using a fastening component provided through the
opening in the proximal end of the seal assembly.
6. The method of claim 5 wherein the seal component is at least one
of a seal or a hoop ring.
7. The method of claim 5 wherein a pressure stroke of the liquid
pressurization pump causes angular deformation of the seal
component.
8. The method of claim 5 further comprising venting, through a seal
carrier of the seal assembly, at least one of seal material or
water that leaks relative to the seal component.
9. The method of claim 8 wherein the venting occurs at least in
part through an annular groove in the seal carrier.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional application of Ser. No.
14/641,822, filed on Mar. 9, 2015, which claims priority to U.S.
Provisional Patent Application No. 61/949,798, filed on Mar. 7,
2014 and entitled "Compact Ultrahigh Pressure Dynamic Seal Assembly
with Pressure Activating Backup Ring." The contents of this
application are incorporated herein by reference in their
entirety.
FIELD OF THE INVENTION
[0002] The invention relates generally to the field of liquid
pressurization systems and processes. More specifically, the
invention relates to methods and apparatuses for improving seal
assemblies operating in high-pressure intensifier pumps.
BACKGROUND
[0003] Liquid pressurization systems produce high pressure (e.g.,
up to 90,000 pounds per square inch or greater) streams of liquid
for various applications. For example, high pressure liquid may be
delivered to a liquid jet cutting head, a cleaning tool, a pressure
vessel or an isostatic press. In the case of liquid jet cutting
systems, liquid is forced through a small orifice at high velocity
to concentrate a large amount of energy on a small area. To cut
hard materials, a liquid jet can be "abrasive" or include abrasive
particles for increasing cutting ability. As used herein, the term
"liquid jet" includes any substantially pure water jet, liquid jet,
and/or slurry jet. However, one of ordinary skill in the art would
easily appreciate that the invention applies equally to other
systems that use liquid pumps or similar technology.
[0004] To generate a high pressure liquid stream, a liquid
pressurization system uses a high-pressure intensifier pump. A
high-pressure intensifier pump uses a plunger to draw a volume of
liquid into a cylinder on an intake stroke and pressurize the
volume of liquid on a pressure stroke. As the plunger reciprocates
within the cylinder, it passes through a seal assembly. The seal
assembly prevents pressurized liquid in the cylinder from flowing
past the plunger and leaking from the pump. Typically, a pump has
multiple cylinders, and pressurized fluid from an outlet area of
each cylinder is collected in an accumulator. High-pressure fluid
collected in this manner is then provided to a tool to perform a
desired function, e.g., cutting or cleaning.
[0005] While seal assemblies are critical to the proper functioning
of the intensifier pump, current seal assemblies suffer from at
least two significant drawbacks. First, current seal assemblies are
bulkier than necessary. Added bulk can waste space in the pump and
raise manufacturing costs. Second, current seal assemblies wear
significantly with pump use and therefore require frequent
replacement. What is needed is a seal assembly that is compact,
robust, and easy to install--and that has a long service life and a
low manufacturing cost.
SUMMARY OF THE INVENTION
[0006] The present invention meets these needs using a new pressure
activating backup ring design that extends seal operating life and
enables a more compact seal assembly structure. The seal assembly
includes a seal carrier, a seal, a hoop ring and a backup ring. The
backup ring "floats" freely in the seal carrier after installation
in the intensifier pump (e.g., does not maintain direct physical
contact with the seal carrier). In some embodiments, a face of the
backup ring is tilted with respect to the seal so that, when
compressed, the backup ring closes around an outer diameter of the
plunger as the seal assembly is exposed to highly pressurized fluid
during the intensifier pump pressure stroke. In some embodiments,
the tilted surface is located elsewhere in the seal assembly, e.g.,
on a face of a press-fit plug that secures seal assembly components
in the seal assembly. The pressure-activating backup ring can
minimize seal material extrusion between the plunger and the backup
ring, allowing seal life to be extended.
[0007] In some embodiments, the backup ring has an inner diameter
that has a clearance relative to an outer diameter of the plunger,
allowing the seal assembly to be easily installed on the plunger.
In some embodiments, the hoop ring provides a buffer between the
seal, the seal carrier and the backup ring and helps to minimize
extrusion of seal material between the seal carrier and the backup
ring. In some embodiments, seal material and water that leak
between the backup ring and the seal carrier are vented to prevent
damage to the backup ring. In some embodiments, internal pieces of
the seal carrier are loaded from the rear and held in place with a
press fit plug (instead of, e.g., being loaded from the front and
held in place with a retainer ring). In such embodiments, a backup
ring with a larger outer diameter can be used, eliminating the
unpredictability of the retainer ring and providing a cleaner look.
In some embodiments, the seal material is retracted within the seal
carrier (e.g., as compared with past designs using a thin-walled
"nose" portion shown and discussed below), reducing lateral
stresses applied to the seal carrier during pump operation and
enhancing the fatigue life of the seal carrier.
[0008] In one aspect, the invention features a seal assembly for a
high pressure liquid system. The seal assembly includes a seal
carrier. The seal carrier includes a base portion defining a
proximal end and a distal end. The seal carrier defines a bore. The
seal assembly includes a seal disposed within the bore of the seal
carrier. The seal assembly includes a backup ring disposed within
the bore of the seal carrier. The seal assembly includes a hoop
ring disposed substantially between the seal and the backup ring.
The hoop ring has a proximal surface and an outer surface (e.g., a
surface defining an outer diameter).
[0009] In some embodiments, the backup ring is in physical contact
with the seal. In some embodiments, a distal surface of the backup
ring forms a first angle with a proximal surface of the seal. In
some embodiments, the first angle is between about zero and about
eight degrees. In some embodiments, the seal assembly includes a
press fit plug disposed in the bore of the seal carrier. The press
fit plug can contact the backup ring and/or can be oriented
proximally to the backup ring. In some embodiments, the press fit
plug includes a distal surface in contact with the backup ring. In
some embodiments, a proximal surface of the backup ring forms a
second angle with the distal surface of the press fit plug. In some
embodiments, a sum of the first and second angles is between about
zero and about eight degrees.
[0010] In some embodiments, a proximal surface of the backup ring
forms an angle with respect to a vertical plane. In some
embodiments, a distal surface of the backup ring forms an angle
with respect to a vertical plane. In some embodiments, a press fit
plug is disposed in the bore of the seal carrier. In some
embodiments, the press fit plug contacts the backup ring and/or is
oriented proximally to the backup ring. In some embodiments, a
distal surface of the press fit plug forms an angle with respect to
a vertical plane. In some embodiments, a proximal surface of the
backup ring forms an angle with a distal face of the press fit
plug. In some embodiments, any angle with respect to a vertical
plane can be between about zero and about eight degrees. In some
embodiments, a sum of any of the angles made with respect to a
vertical plane can be between about zero and about eight
degrees.
[0011] In some embodiments, the high pressure liquid system is a
liquid jet cutting system. In some embodiments, the seal assembly
includes an o-ring disposed between a portion of the seal carrier
and the seal. In some embodiments, the distal end of the seal
carrier includes a tapered portion and the o-ring is located in the
tapered portion of the seal carrier. In some embodiments, the
backup ring is disposed in a counter-bore in the bore of the seal
carrier. In some embodiments, the hoop ring comprises a metal. In
some embodiments, the backup ring comprises a metal. In some
embodiments, the seal comprises an ultra-high molecular weight
(UHMW) material.
[0012] In some embodiments, the press fit plug includes a chamfered
surface. In some embodiments, the hoop ring has a triangular
cross-section. In some embodiments, an outer diameter of the backup
ring does not contact the seal carrier. In some embodiments, the
backup ring has a clearance relative to an outer diameter of a
plunger inserted within the bore of the seal carrier. In some
embodiments, the seal carrier defines a vent path fluidly
connecting an aperture of the seal carrier with an exterior surface
in a low-pressure region of the seal carrier.
[0013] In some embodiments, the vent path includes an annular
groove in the seal carrier. In some embodiments, the distal end of
the seal carrier includes a sealing surface. In some embodiments,
the distal end includes a tapered portion including the sealing
surface, the sealing surface including a departing angle of at
least about two degrees. In some embodiments, an axial length of
the seal assembly is less than about 0.75 inches.
[0014] In another aspect, the invention features a seal component
for a seal assembly of a high pressure liquid system. The seal
component includes a body defining a substantially cylindrical
aperture. The body includes at least one of a first axial surface
defining an outer diameter, a second axial surface defining an
inner diameter, a third surface for engaging at least one of a
press fit plug or a seal carrier, and a fourth surface for engaging
at least one of a seal or a hoop ring when exposed to a pressure
load. At least a portion of the second circumferential surface is
angled relative to a vertical plane. In some embodiments, the seal
component is a backup ring. In some embodiments, the fourth surface
is angled radially outward. In some embodiments, the fourth surface
is angled between about two and about ten degrees.
[0015] In another aspect, the invention features a method of
locating a seal and a seal component in a seal assembly having a
base portion defining a proximal end and a distal end. The method
includes inserting, through an opening in the proximal end of the
seal assembly, the seal into the seal assembly. The method includes
placing, through the opening in the proximal end of the seal
assembly, the seal component in contact with the seal within the
seal assembly. The method includes securing the seal and the seal
component in the seal assembly using a fastening component provided
through the opening in the proximal end of the seal assembly.
[0016] In some embodiments, the seal component is at least one of a
seal or a hoop ring. In some embodiments, the alignment surface is
a distal surface of a press fit plug disposed in the seal assembly.
In some embodiments, a pressure stroke of the liquid pressurization
pump causes angular deformation of the seal component. In some
embodiments, the method includes venting, through a seal carrier of
the seal assembly, at least one of seal material or water that
leaks relative to the seal component. In some embodiments, the
venting occurs at least in part through an annular groove in the
seal carrier.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The foregoing discussion will be understood more readily
from the following detailed description of the invention when taken
in conjunction with the accompanying drawings.
[0018] FIG. 1 is a close-up schematic illustration of a section of
a high-pressure intensifier pump for a liquid pressurization
system.
[0019] FIG. 2 is a schematic illustration of a prior art seal
assembly having a bearing with a positional constraint relative to
a hard seal contact point.
[0020] FIG. 3 is a front-perspective, half-sectional schematic
illustration of a seal assembly, according to an illustrative
embodiment of the invention.
[0021] FIG. 4 is a close-up schematic illustration of a seal
assembly (e.g., the seal assembly shown in FIG. 3), according to an
illustrative embodiment of the invention.
[0022] FIG. 5 is a rear-perspective, half-sectional schematic
illustration of a seal assembly (e.g., the seal assembly shown in
FIG. 3), according to an illustrative embodiment of the
invention.
[0023] FIG. 6 is a side-perspective view of a compact, ultrahigh
pressure seal assembly (e.g., the seal assembly shown in FIG. 3)
with a plunger inserted through the bore of the seal assembly,
according to an illustrative embodiment of the invention.
[0024] FIG. 7 is a perspective view of a compact, ultrahigh
pressure seal assembly (e.g., the seal assembly shown in FIG. 3)
(left), according to an illustrative embodiment of the invention,
beside a prior art seal assembly (right) manufactured by Flow
International Corporation.
[0025] FIG. 8 is a schematic illustration of a method of locating a
seal and a seal component in a seal assembly, according to an
illustrative embodiment of the invention.
[0026] FIGS. 9A-B are close-up cross-sectional views of a seal
assembly having a backup ring with a knife edge having an angled
portion, according to an illustrative embodiment of the
invention.
[0027] FIGS. 10A-10F are close-up cross-sectional schematic
illustrations of seal assemblies (e.g., alternative configurations
to the seal assembly shown in close-up in FIG. 4), according to
illustrative embodiments of the invention.
DETAILED DESCRIPTION OF THE DRAWINGS
[0028] FIG. 1 is a close-up schematic illustration of a
high-pressure intensifier pump 100 for a liquid pressurization
system. The intensifier pump 100 includes a check valve 104, a
pressurization cylinder 108, a plunger 112 and a seal assembly 116.
The intensifier pump 100 draws liquid (e.g., filtered water) in
through the check valve 104 and into the pressurization cylinder
108 on an intake stroke of the plunger 112. As the intensifier pump
100 cycles, the plunger 112 reciprocates within a bore of the seal
assembly 116. To prevent fluid from leaking from the cylinder 108
into the intensifier pump 100, the seal assembly 116 forms a
"dynamic" seal around the plunger 112 (e.g., as shown and described
in detail below in FIGS. 3-6). In some embodiments, the seal
assembly 116 also forms a metal-to-metal seal with the cylinder 108
to prevent leakage within the intensifier pump 100. A pump may have
multiple cylinders, with pressurized fluid from cylinder collected
in an accumulator (not shown).
[0029] FIG. 2 is a schematic illustration of a prior art seal
assembly 200 shown and described in FIG. 8 of U.S. Pat. No.
7,568,424, which is owned by Flow International Corporation. The
prior art seal assembly 200 includes a seal carrier 52, a bearing
66, and a hard seal contact point 204. The bearing 66 is
press-fitted into the seal carrier 52, e.g., to prevent the seal
material from extruding between an outer diameter of the bearing 66
and an inner diameter of the seal carrier 52. When installed in an
intensifier pump, the seal carrier 52 forms a metal-to-metal seal
with the high pressure cylinder, causing a compressive force to be
applied to the seal carrier 52 at the hard seal contact point 204.
This force is transmitted through the seal carrier 52 to the
bearing 66, causing the inner diameter of the bearing 66 to
collapse around the outer diameter of the plunger and to close a
seal material extrusion gap between the inner diameter of the
bearing 66 and the outer diameter of the plunger.
[0030] The seal assembly 200 suffers from significant drawbacks.
First, the seal assembly 200 has a constraint on the axial position
of the bearing 66 relative to the hard seal contact point 204, thus
preventing a more compact design from being achieved. In addition,
the seal is held in a thin-walled "nose" (e.g., element 60 as
shown) of the seal assembly. This thin-walled construction can
crack rapidly when exposed to the significant lateral stresses
placed upon this member during operation of the intensifier
pump.
[0031] FIG. 3 is a front-perspective, half-sectional schematic
illustration of a seal assembly 300, according to an illustrative
embodiment of the invention. The seal assembly 300 has a proximal
end 301 and a distal end 302. The proximal end 301 can define a
vertical plane (or, in some embodiments, can define another shape,
e.g. a taper). The seal assembly 300 includes a seal carrier 304
having base portion 305 and a distal end or portion 306 (e.g., a
tapered portion), a seal 308, a backup ring 312, and a hoop ring
316. The seal carrier 304 defines a bore 310, which can be
substantially cylindrical. The seal 308 is disposed within the bore
310 of the seal carrier 304. The backup ring 312 is disposed within
the bore 310 of the seal carrier 304 and is optionally in physical
contact with the seal 308. The hoop ring 316 is disposed
substantially between the seal 308 and the backup ring 312. In some
embodiments, the hoop ring 316 has a proximal surface 317 and a
surface defining an outer diameter 318 (e.g., as shown below in
FIG. 4).
[0032] In some embodiments, the seal carrier 304 has an annular
groove 324 in the bore 310. The annular groove 324 can receive an
o-ring that provides a water-tight seal between the seal carrier
304 and the seal 308. In some embodiments, the o-ring is located in
the distal (e.g., tapered) portion 306 of the seal carrier 304. In
some embodiments, the seal carrier 304 has a surface 328 for mating
to a pump cylinder (e.g., the cylinder 108 shown and described
above in FIG. 1) of an intensifier pump (e.g., the intensifier pump
100 shown and described above in FIG. 1), forming a metal-to-metal
seal.
[0033] In some embodiments, the surface 328 is divided into
subsections 328A-328E, which can be tapered at distinct angles to
each other. In some embodiments, one or more of the surfaces 328A-E
form a departing angle of at least about two degrees with respect
to a pump cylinder. In some embodiments, the surface 328C includes
a cone angle that matches a mating cone angle on a pump cylinder.
In some embodiments, the surfaces 328B and 328D have cone angles
that depart from the cone angle (and/or the mating cone angle),
e.g., by about two degrees. In some embodiments, a "departing
angle" forces a hard seal between the cylinder and the seal carrier
304 to occur at a diameter defined by surface 328C. In some
embodiments, if the departing angle(s) is (are) too large (e.g.,
are about five degrees), the surface 328C will "dig" into the
cylinder, causing permanent plastic deformation of the cylinder
mating face. In some embodiments, if a departing angle(s) is (are)
too small (e.g. are about one degree) a contact force will not be
localized enough to form a seal, and a hard seal between the
cylinder and the seal carrier 304 can leak. In some embodiments, a
departing angle is between about two and about ten degrees.
[0034] In some embodiments, the seal carrier 304 has a counter-bore
332 for receiving the backup ring 312. In some embodiments, the
counter-bore 332 is a groove. In some embodiments, the backup ring
312 does not contact the seal carrier 304 (e.g., the backup ring
312 "floats" freely in the seal carrier 304). In some embodiments,
the hoop 316 rests entirely on the face of the backup ring 312,
strengthening the backup ring 312 and removing localized stress
from the backup ring 312. In some embodiments, the seal assembly
300 includes a press fit plug 320. The press fit plug 320 holds the
internal pieces (e.g., the seal 308, the backup ring 312, and the
hoop ring 316) in place within the seal carrier 304. In some
embodiments, the press fit plug 320 contacts the backup ring 312.
In some embodiments, the press fit plug 320 is oriented proximally
to the backup ring 312. In some embodiments, the backup ring 312
has a clearance relative to an outer diameter of a plunger inserted
within the bore 310 of the seal carrier 304. In some embodiments,
the seal 308 is made from a plastic material, e.g., an ultrahigh
molecular weight (UHMW) plastic. In some embodiments, the hoop ring
316 comprises a metal. In some embodiments, the backup ring 312
comprises a metal alloy, for example bronze or a bronze alloy. In
some embodiments, the press fit plug 320 includes a chamfered
surface.
[0035] FIG. 4 is a close-up schematic illustration of a seal
assembly (e.g., the seal assembly 300 shown in FIG. 3), according
to an illustrative embodiment of the invention. The backup ring 312
has an outer diameter 358, an inner diameter 359, a proximal
surface 350 and a distal surface 352. The press fit plug 320 has a
distal surface 356, and the seal 308 has a proximal surface 354. In
this view, the backup ring 312 does not maintain direct physical
contact with the seal carrier 304, e.g., "floats freely" in the
seal carrier 304. The distal surface 352 of the backup ring 312
forms a first angle with the proximal surface 354 of the seal 308.
The proximal surface 350 of the backup ring 312 forms a second
angle with the distal surface 356 of the press fit plug 320.
[0036] In some embodiments, the distal surface 352 of the backup
ring 312 is angled with respect to an axial plane (e.g., the
vertical plane 303 shown above in FIG. 3). During the intensifier
pump stroke, the angle facilitates compression of the backup ring
312 as it closes around the plunger. This "pressure activating
backup ring" can help minimize seal material extrusion between the
plunger and the backup ring 312, allowing seal life to be extended.
The metal hoop 316 also minimizes extrusion of seal material by
providing a buffer between the seal carrier 304 (e.g., an inner
diameter of the seal carrier 304), the backup ring 312 (e.g., an
outer diameter of the backup ring 312), and the seal 308.
[0037] In some embodiments, one or more of the following surfaces
is angled (e.g., with respect to the vertical plane 303 as shown
and described above): the distal surface 356 of the press fit plug
320, the proximal surface 350 of the backup ring 312, and/or the
distal surface 352 of the backup ring 312. In some embodiments, the
effects of angling the distal surface 352 of the backup ring 312
can be achieved by angling one or more of the surfaces 350, 352,
356. One skilled in the art will readily appreciate that the sum of
the first and the second angles can be adjusted by appropriately
angling any of these surfaces. In some embodiments, the first angle
is between about zero and about eight degrees, optionally between
about three and about five degrees, optionally about four degrees.
In some embodiments, the second angle is about or exactly zero
degrees (e.g., as shown in FIG. 4). In some embodiments, the sum of
the first and second angles is between about zero and about eight
degrees, optionally between about three to about five degrees,
optionally about four degrees. In some embodiments, the proximal
surface 350 is a surface for engaging (e.g., sealingly engaging) at
least one of a press fit plug or a seal carrier. In some
embodiments, the distal surface 352 is a surface for engaging
(e.g., sealingly engaging) at least one of a seal or a hoop ring
when exposed to a pressure load. In some embodiments, the proximal
surface 350 surface is angled radially outward. In some
embodiments, the distal surface is angled between about two and
about ten degrees. Further illustrative embodiments for angling
surfaces in different combinations are shown below in FIGS.
10A-10F.
[0038] In some embodiments, the counter-bore 332 has a rounded
corner. In some embodiments, the counter-bore 332 has a clearance
of about 0.29 inches diametrically between the outer diameter 358
of the backup ring 312 and the surface 331 of the seal carrier 304.
In some embodiments, the outer diameter 358 does not contact the
seal carrier 304. In some embodiments, the hoop ring 316 has a
triangular cross-section (e.g., as shown in FIG. 4). In some
embodiments, the proximal surface 317 of the hoop ring 316 and the
surface defining the outer diameter 318 form two legs of a right
triangle (e.g., as shown in FIG. 4 in cross-section).
[0039] FIG. 5 is a rear-perspective, half-sectional schematic
illustration of a seal assembly (e.g., the seal assembly 300 shown
above in FIG. 3), according to an illustrative embodiment of the
invention. The base portion 305 has a bottom face 368. The bottom
face 368 includes grooves 370A-C, 374, 378. One or more of the
grooves 370A-C, 374, 378 can assist in venting extruded seal
material and water that leak between the backup ring 312 and the
seal carrier 304 and/or that leak between the backup ring 312 and a
plunger (e.g., to prevent damage to the backup ring 312.) In some
embodiments, the groove 370B is in the shape of a half-cylinder. In
some embodiments, the groove 370A is located at or near one end of
the groove 370B, e.g., on a rear face of the seal carrier 304. In
some embodiments, the groove 370C is located at or near an opposite
end of the groove 370B, e.g., toward the bore 310 of the seal
carrier 304. In some embodiments, the groove 370 is centered along
a diameter of the bottom face 368 of the seal carrier 304. In some
embodiments, one or more of the grooves 370, 374, 378 form a vent
path fluidly connecting an aperture of the seal carrier 304 with an
exterior surface in a low pressure region of the seal carrier 304.
In some embodiments, the groove 374 is an annular groove.
[0040] FIG. 6 is a side-perspective view of a compact, ultrahigh
pressure seal assembly (e.g., the seal assembly 300 shown above in
FIG. 3) with a plunger 390 inserted through the bore 310 of the
seal assembly 300, according to an illustrative embodiment of the
invention. The backup ring (e.g., the backup ring 312 shown and
described above) has a clearance relative to an outer diameter of
the plunger 390, promoting ease of assembly. In some embodiments,
the clearance is about 0.001 inches diametrically.
[0041] FIG. 7 is a perspective view of a compact, ultrahigh
pressure seal assembly (e.g., the seal assembly 300 shown in FIG.
3) (left), according to an illustrative embodiment of the
invention, beside a prior art seal assembly (right) manufactured by
Flow International Corporation. The left seal assembly eliminates
the position constraint of the right seal assembly (e.g., with
respect to the position of the backup ring relative to the seal
carrier hard seal contact point, as shown and described above in
FIG. 2). The left seal assembly can have an axial length of less
than 0.75 inches, for example about 0.71 inches, whereas the right
seal assembly has an axial length of over one inch, or about 1.04
inches. In addition, in the left seal assembly, the seal is pulled
back within the body of the seal assembly relative to the pump
cylinder. In some embodiments, eliminating the thin-walled "nose"
portion of the right seal carrier can enhance the fatigue life of
the seal carrier. In some embodiments, the left seal assembly has a
shorter overall axial length, a more compact seal assembly design,
and/or a lower cost of goods sold. Ratios of certain linear and
circumferential dimensions in some embodiments are further shown
and described below in FIGS. 10A-10C.
[0042] FIG. 8 is a schematic illustration of a method 800 of
locating a seal and a seal component in a seal assembly (e.g., the
seal assembly 300 as shown and described above), according to an
illustrative embodiment of the invention. The method 800 includes a
first step 810 of inserting, through an opening in a proximal end
of the seal assembly, the seal into the seal assembly. The method
800 includes a second step 820 of placing, through the opening in
the proximal end of the seal assembly, the seal component in
contact with the seal within the seal assembly. The method 800
includes a third step 830 of securing the seal and the seal
component in the seal assembly using a fastening component provided
through the opening in the proximal end of the seal assembly. The
steps 810, 820 and 830 do not necessarily occur in chronological
order, but are labeled as "first," "second" and "third,"
respectively, for convenience of reference.
[0043] In some embodiments, the fastening component of the method
800 is a press fit plug. In some embodiments, the method 800
further includes inserting a plunger within a bore of the seal
assembly, e.g., through the proximal or the distal end of the seal
assembly. In some embodiments, the method 800 includes energizing
the seal component via a pressure stroke of the plunger. In some
embodiments, the energizing causes angular deformation of the seal
component. In some embodiments, a position of the seal within the
tapered portion of the seal assembly substantially counteracts
outward stresses on the seal during the pressure stroke. In some
embodiments, the method 800 includes venting, through a seal
carrier of the seal assembly, at least one of seal material or
water that leak between an outer diameter of the seal component and
an inner diameter of the seal carrier. In some embodiments, the
venting occurs at least in part through an annular groove in the
seal carrier. In some embodiments, the seal is located at least
substantially in the tapered portion of the seal assembly.
[0044] In some embodiments, the force includes a tangential
component, the tangential component causing the seal component to
rotate within the seal assembly. In some embodiments, the
tangential component facilitates alignment of the seal component
within the seal assembly. In some embodiments, the seal component
is at least one of a seal or a hoop ring. In some embodiments, the
alignment surface is a distal surface of a press fit plug disposed
in the seal assembly. In some embodiments, the pressure stroke of
the liquid pressurization pump causes angular deformation of the
seal component. In some embodiments, the method 900 further
includes venting, through a seal carrier of the seal assembly, at
least one of seal material or water that leaks relative to the seal
component. In some embodiments, venting occurs at least in part
through an annular groove in the seal carrier.
[0045] FIGS. 9A-B are close-up cross-sectional views of a seal
assembly 1100 having a backup ring 1104 with a knife edge 1108 (see
FIG. 9B) having an angled portion 1112 (see FIG. 9B), according to
an illustrative embodiment of the invention. The seal assembly 1100
can contain similar component parts as the seal assemblies shown
and described herein, e.g., a seal carrier 1116, a seal carrier
vent 1120, a seal 1124, a metal hoop 1128, and/or an o-ring 1132.
In some embodiments, the knife edge 1108 of the backup ring 1104
includes an angled portion 1112 that mates with the seal 1124. Such
a design allows the knife edge 1108 to close around an outer
diameter of a reciprocating plunger when the seal assembly 1100 is
exposed to ultrahigh fluid pressure during a pressure stroke of an
intensifier pump. In some embodiments, the backup ring 1104 helps
to minimize seal material extrusion between the plunger and the
knife edge 1108 of the backup ring 1104, allowing seal life to be
extended. In some embodiments, the metal hoop 1128 minimizes
extrusion of seal material between the seal carrier 1116 and the
backup ring 1104. In some embodiments, seal material and water that
leak between the backup ring 1104 and the seal carrier 1116 are
vented to prevent damage to the backup ring 1104 (e.g., similarly
as shown and described above in FIG. 5).
[0046] FIGS. 10A-10F are close-up cross-sectional schematic
illustrations of seal assemblies 1200A-F (e.g., alternative
configurations to the seal assembly shown in close-up in FIG. 4),
according to illustrative embodiments of the invention. The seal
assemblies 1200A-F include seal carriers 1204A-F, backup rings
1208A-F, hoop rings 1212A-F, and seals 1216A-F, e.g., similar to
corresponding component parts shown and described above. In FIG.
10A, the hoop ring 1212A has an outer diameter 1213A that is angled
with respect to the seal carrier 1204A. In FIG. 10B, the hoop ring
1212B has an outer diameter 1213B that is not angled (or is "flat")
with respect to the seal carrier 1204B. In some embodiments, the
angled outer diameter 1213A redistributes a contact force between
the hoop ring 1211A and the seal carrier 1204A away from a corner
1205A of the seal carrier 1204A. In some embodiments, an angle
formed between the seal carrier 1204A and the hoop ring 1212A is
about three degrees.
[0047] In FIG. 10C, the hoop ring 1212C has a back surface 1214C
that is angled with respect to the backup ring 1208C. In FIG. 10D,
the hoop ring 1212D has a back surface 1214D that is not angled (or
is "flat") with respect to the backup ring 1208D. In some
embodiments, the angled back surface 1214C shifts the hoop ring
1212C forward such that an outer diameter 1213C of the hoop ring
1212C cannot "wrap around" a corner 1205C of the seal carrier
1204C. In some embodiments, an angle formed between the angled back
surface 1214C of the hoop ring 1212C and a reference plane 1220C is
about three degrees. In FIG. 10E, the hoop ring 1212E has an angle
1250E of about 45 degrees. In FIG. 10F, the hoop ring 1212F has an
angle 1250F of about 30 degrees. In some embodiments, the hoop ring
1212E having the 45 degree angle 1250E results in a greater
cross-sectional area of the hoop ring 1212E, adding more substance
to the hoop ring 1212E as compared with the hoop ring 1212F. In
some embodiments, the hoop ring 1212F having the 30 degree angle
1250F with less substance has increased flexibility by comparison
to the hoop ring 1212E. In some embodiments, the backup ring
1208A-F has a flat face instead of an angled face, and/or may
include a contour that improves or assists loading of the backup
ring 1208A-F onto the plunger.
[0048] While the invention has been particularly shown and
described with reference to specific preferred embodiments, it
should be understood by those skilled in the art that various
changes in from and detail may be made therein without departing
from the spirit and scope of the invention as defined by the
following claims.
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