U.S. patent application number 09/964112 was filed with the patent office on 2002-01-31 for pressure processing a pumpable substance with a flexible membrane.
Invention is credited to Hashish, Mohamed A., Raghavan, Chidambaram, Schuman, Bruce M., Tremoulet, Olivier L. JR..
Application Number | 20020011579 09/964112 |
Document ID | / |
Family ID | 23477669 |
Filed Date | 2002-01-31 |
United States Patent
Application |
20020011579 |
Kind Code |
A1 |
Hashish, Mohamed A. ; et
al. |
January 31, 2002 |
Pressure processing a pumpable substance with a flexible
membrane
Abstract
An apparatus and method for pressure processing a pumpable
substance, such as a pumpable food product or slurry. In one
embodiment, the apparatus includes a pressure vessel having an
inlet valve toward one end and outlet valve toward the other end. A
flexible bladder is coupled between the inlet and outlet valves for
receiving the pumpable substance. The pressure vessel can further
include a high-pressure inlet port for receiving high-pressure
fluid that biases the membrane inwardly to pressure process the
pumpable substance. The pumpable substance is then removed from the
vessel through the outlet valve.
Inventors: |
Hashish, Mohamed A.;
(Bellevue, WA) ; Raghavan, Chidambaram; (Kent,
WA) ; Tremoulet, Olivier L. JR.; (Edmonds, WA)
; Schuman, Bruce M.; (Kent, WA) |
Correspondence
Address: |
SEED INTELLECTUAL PROPERTY LAW GROUP PLLC
701 FIFTH AVE
SUITE 6300
SEATTLE
WA
98104-7092
US
|
Family ID: |
23477669 |
Appl. No.: |
09/964112 |
Filed: |
September 25, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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09964112 |
Sep 25, 2001 |
|
|
|
09374649 |
Aug 13, 1999 |
|
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6305913 |
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Current U.S.
Class: |
251/63.5 ;
251/89.5 |
Current CPC
Class: |
A23L 3/0155 20130101;
F04B 43/084 20130101; F04B 7/0266 20130101 |
Class at
Publication: |
251/63.5 ;
251/89.5 |
International
Class: |
F16K 031/12; F16K
035/00 |
Claims
1. A valve for a high-pressure vessel, comprising: a valve body
having a passage therein including a first portion having an inlet
opening and a second portion having an outlet opening; and a piston
sealably positioned in the passage and axially movable within the
passage between a closed position with the piston blocking fluid
communication between the first and second portions of the passage
and between the inlet opening and the outlet opening and an open
position with the first portion of the passage in fluid
communication with the second portion of the passage and the inlet
opening in fluid communication with the outlet opening.
2. The valve of claim 1, further comprising: a seal between the
piston and a wall of the passage; and a support member positioned
adjacent to the seal to support the seal relative to the
piston.
3. The valve of claim 1 wherein a portion of the valve body has a
fluid passage with a first opening coupleable to a source of
purging fluid and a second opening proximate to the piston for
conveying the purging fluid to the piston.
4. The valve of claim 1 wherein the piston has a first portion
positioned within the passage and a second portion positioned
within a driving cylinder, the driving cylinder being coupleable to
a source of pressurized fluid for moving the piston axially within
the passage.
5. The valve of claim 1 wherein the passage is a valve body
passage, further comprising: an actuator block having an actuator
passage and being slideably engaged with the valve body and movable
relative to the valve body between an aligned position with the
actuator passage axially aligned with the valve body passage and an
offset position with the actuator passage offset from the valve
body passage; and an actuator slideable within the actuator passage
between an engaged position with the actuator engaged with the
piston and a disengaged position with the actuator spaced apart
from the piston.
6. The valve of claim 1 wherein the first portion of the passage is
elongated and extends at an angle of approximately 90 degrees
relative to the second portion of the passage.
7. The valve of claim 1, further comprising a seal positioned
within the passage adjacent the piston when the piston is in the
closed position, the seal being spaced apart from the piston when
the piston is in the open position; and a seal shield positioned
within the passage and axially movable between a first position
with the seal shield at least partially covering the seal when the
piston is in the open position, and a second position with the seal
shield spaced apart from the seal when the piston is in the closed
position.
8. The valve of claim 7, further comprising a biasing device
coupled to the seal shield for biasing the seal shield toward the
first position.
9. The valve of claim 1 wherein the high-pressure vessel has a
cylindrical opening and at least a portion of the valve body has a
cylindrical external shape for fitting within the cylindrical
opening of the high-pressure vessel.
10. The valve of claim 1 wherein the valve body is configured to
withstand an internal pressure from within the passage of at least
approximately 100,000 psi.
11. A valve for regulating a flow of fluid into or out of a
pressure vessel, comprising: a valve body having a first fluid
passage coupled to a source of a first fluid and a second fluid
passage coupled to a source of a second fluid, the second fluid
passage having an opening into the high-pressure vessel; a sealing
member positioned proximate to the opening of the second fluid
passage and movable relative to the opening between a closed
position with the sealing member sealed against the valve body and
generally blocking fluid communication between the opening and the
pressure vessel and an open position with the sealing member spaced
apart from the opening to allow fluid communication between the
opening and the pressure vessel; and a piston sealably positioned
in the first fluid passage adjacent the sealing member and movable
within the first fluid passage between a retracted position when
the sealing member is in the closed position and an extended
position when the sealing member is in the open position.
12. The valve of claim 11, further comprising the source of the
first fluid wherein the first fluid includes a liquid.
13. The valve of claim 11, further comprising the source of the
second fluid wherein the second fluid includes a gas.
14. The valve of claim 11, further comprising a biasing member
coupled to the sealing member to bias the sealing member toward the
closed position.
15. The valve of claim 11 wherein the first fluid passage is one of
a plurality of first fluid passages in the valve body.
16. The valve of claim 11 wherein the second fluid passage is one
of a plurality of second fluid passages in the valve body.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is a divisional of U.S. patent application
Ser. No. 09/374,649, filed Aug. 13, 1999, now pending, which
application is incorporated herein by reference in its
entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention relates to methods and devices for pressure
processing pumpable substances, such as food or abrasive slurries,
using a flexible membrane.
[0004] 2. Description of the Related Art
[0005] Conventional ultrahigh-pressure fluid systems have been used
to pressurize pumpable substances, such as foods and slurries. For
example, conventional ultrahigh-pressure systems have been used to
improve the quality and longevity of food by subjecting the food to
pressures in excess of 10,000 psi. Conventional systems have also
been used to pressurize abrasive slurries to ultrahigh-pressure
levels. The slurries can then be directed toward a substrate in the
form of a liquid jet to cut the substrate or treat the surface of
the substrate.
[0006] One conventional system includes a high-pressure cylinder
with a slidable piston that divides the cylinder into two regions.
The pumpable substance is placed in one region while a
high-pressure fluid is introduced into the other region, driving
the piston against the pumpable substance at a very high pressure.
One potential drawback with this system is that as the piston may
require specially designed seals to prevent the high-pressure fluid
from being transported by the piston into the pumpable substance
region. The seals may require periodic monitoring and replacement.
Accordingly, it may be desirable to use an improved apparatus for
pressurizing a pumpable substance while reducing the likelihood for
contact between the pumpable substance and the pressurizing
liquid.
BRIEF SUMMARY OF THE INVENTION
[0007] The invention relates to methods and apparatus for pressure
processing a pumpable substance, such as a food substance. In one
embodiment, the apparatus includes a generally rigid high-pressure
vessel having a first opening toward one end, a second opening
toward the other end, and an internal vessel wall between the first
and second ends. A flexible membrane is disposed within the vessel
and has a first membrane opening in fluid communication with the
first open end of the vessel and a second membrane opening in fluid
communication with the second opening of the vessel. At least a
portion of the membrane is movable away from the vessel wall to
pressurize a portion of the pumpable substance positioned adjacent
to the membrane.
[0008] In one embodiment, the second membrane opening can be
positioned beneath the first membrane opening so that the pumpable
substance can exit the membrane through the second opening under
the force of gravity. In another embodiment, valves are coupled to
the first and second openings of the high-pressure vessel. In one
aspect of this embodiment, the valves can each include a passage
having a first portion with a first opening and second portion with
a second opening. A piston is sealably positioned in the passage
and axially movable within the passage between a closed position
with the piston blocking fluid communication between the first and
second openings and an open position with the first and second
openings being in fluid communication with each other. The pumpable
substance can be pumped into the membrane through the first
opening, pressurized within the membrane by a high-pressure fluid
disposed between the membrane and an inner wall of the vessel, and
released from the pressure vessel through the second opening.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0009] FIG. 1 is a partially schematic, partial cross-sectional
side elevation view of an apparatus having an inlet valve, an
outlet valve and a bladder in accordance with an embodiment of the
invention.
[0010] FIG. 2 is a detailed partial cross-sectional side elevation
view of an upper portion of the apparatus of FIG. 1 showing the
inlet valve in its open position.
[0011] FIG. 3 is a detailed partial cross-sectional side elevation
view of the upper portion of the apparatus of FIG. 1 showing the
inlet valve in its closed position.
[0012] FIG. 4 is a detailed partial cross-sectional side elevation
view of the lower portion of the apparatus of FIG. 1 showing the
outlet valve in its closed position.
[0013] FIG. 5 is a partial cross-sectional side elevation view of
the apparatus shown in FIG. 1 having an inlet valve in accordance
with another embodiment of the invention.
[0014] FIG. 6 is a partial cross-sectional top view of the inlet
valve of FIG. 5 shown in its open position.
[0015] FIG. 7 is a partial cross-sectional top view of the inlet
valve of FIG. 5 shown in its closed position.
DETAILED DESCRIPTION OF THE INVENTION
[0016] In general, conventional devices for pressure processing
pumpable substances have been directed to high-pressure cylinders
having an internal piston and/or having an inlet and outlet for the
pumpable substance at one end of the cylinder and an inlet and
outlet for the high-pressure fluid at the opposite end of the
cylinder. By contrast, one aspect of the present invention includes
a high-pressure cylinder having a flexible bladder with an entrance
opening for the pumpable substance at one end of the bladder and an
exit opening for the pumpable substance at the opposite end of the
bladder. Accordingly, in one embodiment, the pumpable substance can
be introduced through an inlet port at one end of the cylinder and
removed from an outlet port at the opposite end of the cylinder,
reducing the likelihood for contamination of the outlet port with
unpressurized pumpable substance. The apparatus can also take
advantage of gravitational forces to more completely remove the
pumpable substance from the pressure vessel. Furthermore, by
separating the inlet and outlet ports, each port can be larger,
increasing the rate at which the pumpable substance can be moved
into and out of the bladder, and increasing the size of pumpable
substance constituents that can pass into and out of the
bladder.
[0017] An apparatus 10 for pressure processing a pumpable substance
in accordance with an embodiment of the invention is shown in FIG.
1. The apparatus 10 includes a pressure vessel 12 that receives the
pumpable substance from a pumpable substance source 30 and
pressurizes the pumpable substance with fluid supplied by a
high-pressure fluid source 41. The pressure vessel 12 can include
an open-ended cylinder 13 surrounded by a protective cylindrical
shield 14. Two valve assemblies 20, shown as an inlet valve
assembly 20a and an outlet valve assembly 20b, cap opposite ends of
the cylinder 13, and are clamped against the cylinder 13 with a
yoke 11. A flexible bladder 50 is coupled between the valve
assemblies 20. The pumpable substance is pumped into the bladder 50
through the inlet valve assembly 20a, pressurized by high-pressure
fluid entering the cylinder 13 from the high-pressure fluid source
41, and pumped through the outlet valve assembly 20b to a
receptacle 80, as will be discussed in greater detail below.
[0018] In one embodiment, the pressure vessel 12 can include a
model number 012122 assembly available from Flow International
Corporation of Kent, Wash. that includes the cylinder 13, the yoke
11 and the shield 14, configured to withstand an internal vessel
pressure of at least 100,000 psi. In other embodiments, the
pressure vessel 12 can include other cylinders 13 and peripheral
components configured to withstand an internal pressure of 100,000
psi or another suitable pressure, depending upon the selected
pumpable substance and treatment. Such vessels and components are
available from ABB Pressure Systems of Vasteras, Sweden, Autoclave
Engineering of Erie, Pa., or Engineered Pressure Systems of
Andover, Mass.
[0019] The pressure vessel 12 can include a liner 15 adjacent an
inner surface of the cylinder 13. The liner can be formed from
stainless steel or other suitable materials that can withstand the
high internal pressures within the cylinder 13. In one embodiment,
the liner 15 can be attached to the cylinder 13 by first heating
the cylinder 13 so that it expands, then placing the cylinder 13
around the liner 15, and then cooling the cylinder 13 so that it
shrinks tightly around the liner 15. If the liner 15 later becomes
worn or damaged, it can be removed from the cylinder 13 and
replaced with a similar liner. An advantage of this arrangement is
that cracks that might result from the high pressure within the
pressure vessel 12 will tend to form in the liner 15 rather than in
the cylinder 13, and it may be easier and less expensive to replace
the liner 15 than the cylinder 13.
[0020] FIG. 2 is an enlarged cross-sectional side elevation view of
the upper portion of the apparatus 10 shown in FIG. 1. As shown in
FIG. 2, the inlet valve assembly 20a fits partially within the
cylinder 13 and includes a flow channel 31 having a radial portion
32 in fluid communication with an axial portion 33. Both the radial
portion 32 and the axial portion 33 can be strengthened or
reinforced, for example, by passing through these portions a die
having a slightly oversized diameter, or by using other known
strengthening techniques. An inlet port 27a at one end of the
radial portion 32 is coupled to the pumpable substance source 30
(FIG. 1). A bladder port 34 at the opposite end of the axial
portion 33 is coupled to the bladder 50. An inlet sealing piston
22a moves axially upwardly and downwardly within the axial portion
33 between an open position (shown in FIG. 2) in which the pumpable
substance can pass into the bladder 50 and a closed position
(discussed in greater detail below with reference to FIG. 3) in
which the pumpable substance is sealed within the bladder 50.
[0021] When the inlet valve assembly 20a is in its open position,
the inlet sealing piston 22a is retracted upwardly into a sealing
block 23. An upper piston seal 70a, disposed annularly about the
inlet sealing piston 22a, seals the interface between the inlet
sealing piston 22a and the axial portion 33 of the flow channel 31
to at least restrict the pumpable substance from passing upwardly
along the inlet sealing piston 22a. A lower fluid gap 38a extends
annularly about the inlet sealing piston 22a, just above the upper
piston seal 70a, for collecting and removing pumpable substance
that might escape past the upper piston seal 70a. Purging fluid can
be pumped through an upper inlet port 28a and into the lower fluid
gap 38a, where it can entrain pumpable substance that might be
present in the lower fluid gap 38a. The purging fluid and entrained
pumpable substance can then be removed through an upper exit port
29a. In one embodiment, the purging fluid can include water, and in
other embodiments the purging fluid can include iodine or other
substances that sanitize the surfaces in contact with the purging
fluid.
[0022] The inlet valve assembly 20a further includes a lower seal
70b beneath the upper seal 70a. When the inlet sealing piston 22a
is in its open position (as shown in FIG. 2), the lower seal 70b is
covered with a sleeve 74 that is biased upwardly by a sleeve spring
75. The sleeve 74 protects the lower seal 70b from contact with the
pumpable substance. The lower seal 70b is exposed and seals against
the inlet sealing piston 22a when the inlet sealing piston 22a is
moved to its closed position, as will be discussed in greater
detail below.
[0023] The inlet sealing piston 22a is driven from its open
position to its closed position by a driver piston 21 that moves
axially within the sealing block 23. Accordingly, the sealing block
23 includes a driver fluid port 25 that supplies pressurized fluid
to the driver piston 21 to move the driver piston and the inlet
sealing piston 22a together in a downward direction. The sealing
block 23 itself can slide laterally along a block rail 24 to secure
the inlet sealing piston 22 in the closed position. Accordingly,
the sealing block 23 can include an actuator 26 that moves the
sealing block 23 laterally back and forth along the block rail
24.
[0024] In operation, the inlet sealing piston 22a moves downwardly
from its open position to its closed position under the force of
the driver piston 21. As the inlet sealing piston 22a moves
downwardly, it engages the sleeve 74, forcing the sleeve downwardly
against the resistance provided by the sleeve spring 75. At this
point, both the upper seal 70a and the lower seal 70b seal against
the inlet sealing piston 22a and the inlet sealing piston 22a
blocks communication between the radial portion 32 and the axial
portion 33 of the flow channel 31. The inlet sealing piston 22a
continues to move in a downward direction until an end cap 35 at
the upper end of the inlet sealing piston 22a is aligned with a cap
engaging surface 36 of the sealing block 23. The sealing block 23
then slides laterally as indicated by arrow A along the block rail
24 until the end cap 35 engages the cap retaining surface 36. The
inlet sealing piston 22a is accordingly secured in its closed
position.
[0025] To open the valve 20a, the sealing block 23 is moved
laterally as indicated by arrow B until the driver piston 21 is
axially aligned with the inlet sealing piston 22a. The sleeve
spring 75 then moves the sleeve 74 upwardly, and the sleeve 74
together with pressure from within the bladder 50 drive the inlet
sealing piston 22a upwardly to its open position.
[0026] FIG. 3 is a cross-sectional side elevation view of the inlet
valve 20a of FIG. 2 shown in the closed position. The inlet sealing
piston 22a has moved downwardly in the axial portion 33 of the flow
channel 31 and the sealing block 23 has moved laterally so that the
cap engaging surface 36 engages the end cap 35 to prevent the inlet
sealing piston 22a from moving in an upward direction. The inlet
sealing piston 22a has moved the sleeve 74 downwardly so that the
lower piston seal 70b engages the inlet sealing piston 22a.
Accordingly, the lower fluid gap 38a, now positioned just above the
lower piston seal 70b, is aligned with a lower inlet port 28b and a
lower exit port 29b to remove pumpable substance from the lower
fluid gap 38a in a manner generally similar to that discussed above
with reference to FIG. 2. An upper fluid gap 38b is aligned with
the upper inlet port 28a and the upper exit port 29a to operate in
a manner similar to that discussed above with reference to FIG. 2.
Accordingly, the inlet valve 20a can prevent the pumpable substance
from escaping upwardly past the inlet sealing piston 22a when the
inlet valve 20a is in its closed position and the bladder 50 is
under pressure.
[0027] As shown in FIG. 3, the bladder 50 is attached to the sleeve
74 to receive the pumpable substance through the inlet valve 20a.
In one embodiment, the bladder 50 includes an elongated tube having
an upper opening 54. The bladder 50 can be formed from rubber,
neoprene or any flexible, generally nonporous material. In one
embodiment, the bladder 50 can include a medical-grade rubber
suitable for use with food products. In another embodiment, the
bladder 50 can include an abrasion-resistant rubber or other
abrasion resistant material for use with abrasive slurries. In
still another embodiment, the bladder 50 can include a laminate of
multiple plies bonded together with an adhesive, such as a rubber
cement. One advantage of this embodiment is that the bladder 50 can
separate the pumpable substance from the high-pressure fluid even
if one or more of the plies has a pin hole or other puncture.
Another advantage is that the multiple plies can thicken the
bladder 50 and provide thermal insulation between the pumpable
substance and the high-pressure fluid. Accordingly, hot or cold
pumpable substances can be pressure processed in the pressure
vessel 12 with a reduced transfer of heat to or from the pumpable
substance.
[0028] A bladder fitting 51 extends through the upper opening 54 of
the bladder 50 and is attached to the bladder 50 with a band 53 or
alternatively, with a food-grade adhesive that discourages
microorganism growth, or another suitable securing device. The
bladder fitting 51 is then coupled to the sleeve 74 with a
removable coupling 52, such as are available from Tri-Clover, Inc.,
of Kenosha, Wis. In one embodiment, the bladder fitting 51 can be
sized to take up a substantial volume within the cylinder 13,
thereby reducing the volume of high-pressure fluid required to
pressurize the bladder 50 and reducing the time required to move
the high-pressure fluid into and out of the cylinder 13.
[0029] FIG. 4 is a cross-sectional side elevation view of the lower
portion of the apparatus 10 shown in FIGS. 1-3. As shown in FIG. 4,
the bladder 50 includes a lower opening 55 attached to a bladder
fitting 51 which is in turn coupled to a sleeve 74 of the outlet
valve assembly 20b. In one embodiment, the bladder 50 can be
stiffer near the lower opening 55 than near the upper opening 54
(FIG. 3) to prevent the bladder 50 from collapsing on itself near
the lower opening 55 when the pumpable substance is removed. In one
aspect of this embodiment, the stiffness of the bladder 50 can
decrease in a generally uniform manner in an upward direction
extending away from the outlet valve assembly 20b. In another
aspect of this embodiment, the bladder 50 can be made stiffer near
the lower opening 55 by increasing the number of plies that form
the bladder 50 in this region.
[0030] The outlet valve assembly 20b includes an outlet sealing
piston 22b, a driver piston 21 and a sealing block 23, all of which
operate in generally the same manner as was discussed above with
reference to the inlet valve assembly 20a shown in FIGS. 2 and 3.
Accordingly, the outlet valve assembly 20b is closed (as shown in
FIG. 4) while the pumpable substance is pressurized, and is opened
to allow the pressurized pumpable substance to pass out of the
bladder 50.
[0031] The outlet valve assembly 20b includes a high-pressure port
40 coupled to the high-pressure fluid source 41 (FIG. 1). The
high-pressure fluid enters the pressure vessel 12 through the
high-pressure port 40 at pressures up to and exceeding 100,000 psi,
fills the region between cylinder 13 and the bladder 50, and
pressurizes the contents of the bladder 50. In one embodiment, the
high-pressure fluid can be water. Alternatively, the high-pressure
fluid can be sterile citric acid or another sterile solution. In a
further aspect of this embodiment, the high-pressure fluid can be
selected to include water at an elevated temperature, for example,
about 100.degree. F. At such elevated temperatures, the ductility
of the metal forming the cylinder 13 can be increased, as
determined using a Charpy test or other ductility tests.
[0032] After pressurization, the pressurized pumpable substance can
be removed through the outlet valve 20b by moving the outlet valve
20b to its open position and allowing the pumpable substance to
pass through a pumpable substance exit port 27b to the receptacle
80 (FIG. 1). In one embodiment, the pumpable substance can exit the
bladder 50 solely under the force of gravity. In one aspect of this
embodiment, the inlet valve 20a is opened to a sterile environment
at atmospheric pressure to allow the pumpable substance to descend
from the bladder 50 under the force of gravity without introducing
contaminants to the bladder 50. In another embodiment, the pumpable
substance can be squeezed from the bladder 50 by filling the
pressure vessel 12 with a fluid at a relatively low pressure. In
one aspect of this embodiment (best seen in FIG. 3), the pressure
vessel 12 can include a low pressure valve 60 for transporting the
low pressure fluid to and from the cylinder 13.
[0033] The low pressure valve 60 (FIG. 3) can include a fluid
passage 62 having a fluid port 61 at one end coupled to a source of
the low pressure fluid (not shown). At the opposite end of the
fluid passage 62 is a movable sealing ring 66 that can be moved
between an open position (shown in FIG. 3) that allows fluid
communication between fluid passage 62 and the interior of the
cylinder 13, and a closed position that prevents such fluid
communication. In one embodiment, the sealing ring 66 is biased
upwardly toward its closed position with a sealing ring spring 67.
The sealing ring 66 can be moved downwardly against the force of
the sealing ring spring 67 to its open position by an actuating
piston 65. The actuating piston 65 can be positioned in a gas
passage 64 and can move downwardly within the gas passage 64 when
gas is supplied through a gas port 63. To close the fluid passage
62, the pressure at the gas port 63 is reduced, allowing the
sealing ring spring 67 to move the sealing ring 66 and the
actuating piston 65 upwardly until the sealing ring seals against
the inlet valve assembly 20a and closes the fluid passage 62.
[0034] In one embodiment, the fluid passage 62 is one of three
fluid passages 62 coupled to the fluid port 61 and spaced
120.degree. apart from each other around the sleeve 74. Similarly,
the gas passage 64 can be one of three gas passages 64 coupled to
the gas port 63 and spaced 120.degree. apart from each other around
the sleeve 74. In other embodiments, the low pressure valve 60 can
include more or fewer fluid passages 62 and gas passages 64. An
advantage of having a plurality of gas passages 64 is that they
more evenly distribute the force applied to the sealing ring 66,
reducing the likelihood that the sealing ring 66 will become cocked
or tilted as it moves up and down. An advantage of having a
plurality of fluid passages 62 is that the low pressure fluid can
be more quickly and uniformly transported into and out of the
cylinder 13. In another embodiment, the outlet valve 20b (FIG. 4)
can also include a low pressure valve generally similar to the low
pressure valve 60 discussed above. An advantage of having two low
pressure valves 60 is that the low pressure fluid can be even more
quickly transported into and out of the cylinder 13. A further
advantage is that the inlet and outlet valves 20a, 20b can be
interchangeable.
[0035] Operation of an embodiment of the apparatus 10 is best
understood with reference to FIG. 1. Initially, the outlet valve
assembly 20b is closed by moving the outlet sealing piston 22b to
its upper position (shown in FIG. 1) and the inlet valve assembly
20a is opened by moving the inlet sealing piston 22a to its upper
position (shown in FIG. 1). The pumpable substance is pumped
through the inlet valve assembly 20a and into the bladder 50. The
inlet valve assembly 20a is then closed by moving the inlet sealing
piston 22a downwardly and high-pressure fluid is pumped through the
high-pressure port 40 of the outlet valve assembly 20b. The
high-pressure fluid fills the space between the bladder 50 and the
liner 15 and biases the bladder 50 inwardly to pressurize the
pumpable substance within the bladder 50. The pumpable substance is
then pressurized for a selected period of time.
[0036] Turning now to FIG. 3, the low pressure valve 60 is opened
by forcing gas through the gas passage 64 to move the actuating
piston 65 against the sealing ring 66. As the sealing ring 66 moves
away from the fluid passage 62, high-pressure fluid escapes through
the fluid passage 62 and out through the fluid port 61. The outlet
valve 20b (FIG. 1) is then opened and fluid is supplied at low
pressure through the low pressure valve 60 to collapse the bladder
50 and force the pressurized pumpable substance out through the
outlet valve 20b. Once the bladder 50 has collapsed, the apparatus
10 is ready to pressure process a new batch of pumpable substance.
After a selected number of pressure cycles, the bladder 50 can be
cleaned, for example, by passing through the bladder (in
succession) a rinse solution, a caustic solution, hot water, a
chemical sterilizer and citric acid.
[0037] An advantage of an embodiment of the apparatus 10 shown in
FIGS. 1-4 is that the bladder 50 can eliminate contact between the
pumpable substance and the high-pressure fluid. Accordingly, the
likelihood that that pumpable substance will be contaminated with
high-pressure fluid (and vice versa) is substantially reduced. A
further advantage is that the inlet valve 20a is separated by a
substantial distance from the outlet valve 20b, reducing the
likelihood of contaminating the pressurized pumpable substance with
unpressurized pumpable substance. Furthermore, by positioning the
outlet valve 20b beneath the inlet valve 20a, the apparatus 10 can
take advantage of gravity to remove the pressurized pumpable
substance from the vessel 12. Accordingly, a greater portion of the
pumpable substance can be removed from the vessel 12 after
pressurization.
[0038] Yet another feature of the apparatus 10 is that the flow
passages 31 through the valves 20 can have relatively large
cross-sectional areas. This is advantageous because it allows the
pumpable substance to enter and exit the vessel 13 more quickly. It
also allows pumpable substances having chunks or large suspended
particles to be more easily directed into and out of the vessel 13.
For example, when the apparatus 10 is used to pressure process
chunks of fruit, such as pineapples, the flow passages 31 can have
diameters of about one inch. In other embodiments, the flow
passages can have other diameters to accommodate chunks of pumpable
substance having other dimensions.
[0039] Still another advantage is that the movable sleeve 74 can
reduce the likelihood of exposing at least one of the piston seals
70b to the pumpable substance. Accordingly, the pumpable substance
is less likely to become trapped in the piston seal 70b. Yet
another advantage is that the flow of purging fluid alongside the
pistons 22 can further reduce the likelihood of pumpable substance
escaping from the vessel 12 when the vessel 12 is under
pressure.
[0040] In the embodiment discussed above with reference to FIGS.
1-4, the pumpable substance is placed within the bladder 50 and the
high-pressure fluid is disposed between the bladder 50 and the
inner walls of the cylinder 13. In another embodiment, the pumpable
substance can be positioned between the bladder 50 and the inner
walls of the cylinder 13 while the high-pressure fluid is disposed
within the bladder 50. An advantage of placing the pumpable
substance in the bladder 50 is that it may be easier to remove the
pumpable substance from within the bladder 50 than from between the
bladder 50 and the walls of the cylinder 13.
[0041] FIG. 5 is a cross-sectional side elevation view of the upper
portion of the apparatus 10 shown in FIG. 1 having an inlet valve
120a in accordance with another embodiment of the invention. The
inlet valve 120a includes a low pressure valve 160 generally
similar in appearance and operation to the low pressure valve 60
discussed above with reference to FIG. 3. The inlet valve assembly
120a further includes a flow channel 131 having an axial portion
133 connected to a radial portion 132. One end of the axial portion
133 is closed with a plug 139, and the other end is coupled to the
bladder 50. As will be discussed in greater detail below, fluid
communication between the axial portion 133 and the radial portion
132 can be opened or closed by moving a piston within the radial
portion 132.
[0042] FIG. 6 is a top, partial cross-sectional view of the inlet
valve 120a shown in FIG. 5. As shown in FIG. 6, the inlet valve
120a includes a sealing piston 122 that moves laterally within the
radial portion 132 of the flow channel 131. When the sealing piston
122 is in its leftmost position (shown in FIG. 6) the pumpable
substance can pass from the radial portion 132 of the flow channel
131 to the axial portion 133 and into the bladder 50 (FIG. 5). When
the sealing piston 122 is in its rightmost position (discussed in
greater detail below with reference to FIG. 7), the sealing piston
122 prevents fluid communication between radial portion 132 and the
axial portion 133.
[0043] The sealing piston 122 is sealed within the radial portion
132 with two piston seal assemblies 170, shown as a left piston
seal assembly 170a and a right piston seal assembly 170b. The right
piston seal assembly 170b is covered with a sleeve 174 when the
inlet valve is in its open position (as shown in FIG. 6). The
sleeve 174 is biased toward the covered position by a sleeve spring
175 when the inlet valve 120a is in the open position, in a manner
generally similar to that discussed above with reference to the
sleeve 74 shown in FIG. 2. The sleeve 174 includes an inlet port
127a coupled to the pumpable substance source 30 (FIG. 1) with a
flexible conduit 126. Accordingly, the conduit 126 can maintain the
connection between the pumpable substance source 30 and the inlet
port 127a as the sleeve 174 moves laterally.
[0044] The seal assemblies 170 can include a seal 171 that extends
between the sealing piston 122 and the walls of the radial portion
132 of the flow channel 131. The seal assemblies 170 can also
include an O-ring 172, an anti-extrusion ring 173 to prevent the
seal 171 from extruding outwardly away from the radial portion 132,
and a backup ring 176 to support the seal 171 and the
anti-extrusion ring 173. This seal assembly arrangement, shown in
detail in FIG. 6, can also be used in conjunction with the seals
70a, 70b shown in FIGS. 1-4.
[0045] A driver piston 121 connected to one end of the sealing
piston 122 drives the sealing piston 122 laterally within the
radial portion 132. The driver piston 121 moves within a driver
cylinder 123 which can include two driver fluid ports 125 (shown as
a left port 125a and a right port 125b). When pressurized fluid is
supplied to the right port 125b, the driver piston 121 and the
sealing piston 122 move to the left toward the open position. When
pressurized fluid is supplied to the left port 125a, the driver
piston 121 and the sealing piston 122 move to the right toward the
closed position.
[0046] FIG. 7 is a top, partial cross-sectional view of the inlet
valve assembly 120a shown in FIG. 6 with the sealing piston 122 and
the driver piston 121 moved to the closed position. As shown in
FIG. 7, the sealing piston 122, when in the closed position,
prevents fluid communication between the radial portion 132 and the
axial portion 133 of the flow channel 131. Accordingly, the sealing
piston 122 can prevent pumpable substance from escaping from the
cylinder 13 when the cylinder is pressurized.
[0047] When the sealing piston 122 is in the closed position, it
engages the sleeve 174 and moves the sleeve 174 to the right (as
seen in FIG. 7) until the sealing piston 122 seals against the
right seal assembly 170b. Fluid gaps 138 (shown as a left fluid gap
138a and a right fluid gap 138b) adjacent the sealing piston 122
receive purging fluid from inlet ports 128 (shown as a left inlet
port 128a and a right inlet port 128b) to purge the region adjacent
the seals 170. The purging fluid, with pumpable substance
entrained, can be removed through exit ports 129a and 129b in a
manner generally similar to that discussed above with reference to
the fluid gaps 38 shown in FIGS. 2 and 3.
[0048] From the foregoing it will be appreciated that, although
specific embodiments of the invention have been described herein
for purposes of illustration, various modifications may be made
without deviating from the spirit and scope of the invention. For
example, the liner 15 can be disposed in a high-pressure vessels
that include means other than the bladder 50 for pressurizing the
pumpable substance. Accordingly, the invention is not limited
except as by the appended claims.
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