AU767911B2 - Method and apparatus for regulating flow of a pumpable substance - Google Patents

Description

3-02:12:20PM;DAVIES COLLISON CAVE A A

AUSTRALIA

PATENTS ACT 1990 DWISIONAL APPLICATION NAME OF APPLICANT: Flow International Corporation ADDRESS FOR SERVICE: DAVIES COLLISON CAVE Patent Attorneys 1 Little Collins Street Melbourne, 3000.

INVENTION TITLE: "Method and apparatus for regulating flow of a pumpabic substance" 'The following statement is a full description of this invention, including the best method of performning it known to us: *0 RECEIVED TIME 30,MAR. 13:28 RECEVEGTIM 3G MA. :28PRINT TIME 2. APR. 11:24 P:\OPER\ArI29210-2 spcdo l( ll0 2 -1- METHOD AND APPARATUS FOR REGULATING FLOW OF A PUMPABLE SUBSTANCE This application is a divisional of Australian Patent Application No. 46924/99, the entire contents of which are incorporated herein by reference.

This invention relates to methods and apparatus for pressure processing a pumpable substance, for example, food substances and the like.

Flowable substances, such as liquid food products, may be treated by exposure to S•ultrahigh-pressures. For example, liquid food products may be preserved or otherwise 10 chemically or physically altered after exposure to ultrahigh-pressures In one conventional S. process, the food substance is loaded into a pressure vessel where it is pressurized to a selected pressure for a selected period of time to achieve the desired physical or chemical change. The vessel is then depressurized and the contents unloaded. The pressure vessel may then be reloaded with a new volume of unprocessed substance and the process may be 15 repeated.

Although current systems produce desirable results, issues of product •contamination can arise. Contamination is an important issue in certain applications, particularly those involving pressure-processing of food substances. Contamination can potentially result from contact between the food substance and the outside environment, or can potentially result from exposure of the pressure processed food product to the unprocessed food product.

One aspect of the invention provides an apparatus for pressure-processing a pumpable substance, comprising: a pressure vessel having an internal surface and at least one port through the internal surface; a valve body disposed in the port and movable relative to the port between an open position and a closed position, the valve body having at least one sealing surface that seals the port and at least restricts motion of the pumpable substance through the port when the valve body is in the closed position, the valve body having a channel with a first opening coupled to a source of purging fluid and a second opening proximate to the port to direct purging fluid into a purging zone adjacent the valve body.

P:Aoprl\292 Io42 spe.doc-.2110//02 -2- Another aspect of the invention provides an apparatus for pressure-processing a pumpable substance, comprising: a pressure vessel having an internal surface and at least one port through the internal surface; a valve body proximate to the port and movable relative to the port between an open position and a closed position, the valve body having at least one sealing surface that seals the port and at least restricts motion of the pumpable substance through the port when the valve body is in the closed position, the valve body having a channel with a first opening coupled to a source of purging fluid and a second opening proximate to the port to 10 direct purging fluid into a region adjacent the valve body.

S "A further aspect of the invention provides a method for pressure processing a pumpable food substance, comprising: transferring the pumpable food substance into in an internal region of a pressure vessel through a port of the pressure vessel; 15 sealing the port by moving a valve body at least adjacent to the port to block flow Sthrough the port; purging a purging region located between the internal region of the pressure vessel and a source of the pumpable food substance by directing a purging fluid through an orifice in the valve body while the valve body blocks flow through the port.

A preferred embodiment of the invention will now be described, by way of example only, with reference to the drawings set out below.

Figure 1 is a partially broken, partial cross-sectional side elevation view of an apparatus having a pumpable substance valve and a high pressure valve.

Figure 2 is a detailed cross-sectional side elevation view of the pumpable substance valve shown in Figure 1.

Figure 3 is a detailed cross-sectional side elevation view of the high pressure valve shown in Figure 1.

The preferred embodiment of the present invention is directed toward methods and apparatus for pressure-processing pumpable substances, such as food products. Details of certain embodiments of the invention are set forth in the following description, and in Figures 1-3, to provide a thorough understanding of such embodiments. One skilled in the P:\OPER\ArI292 04)2 spe.doc-16/I0102 -3art, however, will understand that the present invention may have additional embodiments, and that they may be practiced without several of the details described in the following description.

A pressure processing apparatus of the invention includes a pressure vessel having an internal inlet valve that opens to admit a pumpable substance into the vessel. The inlet valve then closes and the pumpable substance is compressed by a piston that is driven by an ultrahigh-pressure fluid. After the pumpable substance has been pressurized, an internal outlet valve opens to remove the pressurized pumpable substance. The inlet and outlet valves can be supplied with a purging fluid that can reduce the likelihood of contaminating 10 the pressurized pumpable substance by creating a fluid barrier between the pressurized and unpressurized pumpable substances.

S*Figure 1 is a partial cross-sectional elevation view of a pressure-processing apparatus 10 that includes a pressure vessel 15 having an internal surface 14 capable of withstanding high internal pressures. The pressure vessel 15 may include an open-ended 15 cylinder 12 having a pumpable substance valve 30 at one end and a high pressure valve at the opposite end. A yoke 11 secures the pumpable substance valve 30 and the high pressure valve 70 in place when the pressure vessel 15 is subjected to high internal pressures. The pumpable substance valve 30 includes two ports 31, shown in Figure 1 as an inlet port 31 a that admits unpressurized pumpable substance into the pressure vessel and an outlet port 3 lb that evacuates the pumpable substance from the pressure vessel once the pumpable substance has been pressurized. Each of the ports 31 can be sealed and unsealed- with a valve body 40 (shown as an inlet valve body 40a and an outlet valve body The pumpable substance can be pressurized by a piston 13 that is driven by an ultrahigh-pressure fluid to move axially within the pressure vessel 15. The ultrahighpressure fluid is supplied to the pressure vessel 15 through a high pressure conduit 71 in the high pressure valve 70. The ultrahigh-pressure fluid is initially removed from the pressure vessel 15 through the high pressure conduit 71 until the pressure within the vessel is low enough J-U2;12:20PM;DAVIES COLLISON CAVE A- 9 4 to allow the low pressure port 72 to open. Once the low pressure port 72 is opened, the remaining ultra-high pressure fluid can be evacuated from the pressure vessel 15 at a higher rate of flow through the low pressure port.

Figure 2 is a detailed partial cross-sectional elevation view of the pumpable substance valve 30 and a portion of the cylinder 12 shown in Figure 1.

As shown in Figure 2, the pumpable substance valve 30 can include an inlet coupling 33a in fluid communication with the inlet port 31a, and an outlet coupling 33b in fluid communication with the outlet port 31b. The inlet coupling 33a may be coupled to a source of pumpable substance (not shown). to supply the pumpable substance to the pressure vessel 15. The outlet coupling 33b may be coupled to a container or a packaging device to package the pumpable substance once it has been pressure processed.

As mentioned above, the flow of the pumpable substance through the inlet port 31a and the outlet port 31 b is controlled by the inlet valve body 15 and the outlet valve body 40b, respectively. Each valve body 40 is connected with a valve stem 50 to a valve piston 52 that drives the valve body 40 axially between an open position (shown by the position of the outlet valve body 40b in Figure 2) and a closed position (shown by the position of the inlet valve body in Figure Accordingly, each valve piston 52 has a forward face 55 adjacent an opening port 54 and a rear face 56 adjacent a closing port 53. When pressurized fluid is forced through the opening port 54. it acts against the forward face 55 of the valve piston 52 to drive the valve body 40 axially to its open position. When the pressurized fluid is bfrced through the closing port 53, it acts against the rear face 56 of the valve piston 52 to drive the valve body 40 axially to its closed position.

Each valve body 40 can include an external portion 41 that remains external to the corresponding port 31 when the valve body is in the closed position, and an internal portion 42 that extends into the port when the valve body is in the closed position. Each valve body 40 may also include one or more seals that restrict the motion of the pumpable substance past the valve body when the valve body is in the closed position. For example, the valve body 40 can RECEIVED TIME 30. MAR, 13:28 PRINT TIME 2. APR. 11:24 '-UZ;12:20PM;DAVIES COLLISON

CAVE

A- include a flexible seal 43 around the pcriphery of the external portion 41. The flexible seal 43 can be held in place by a lip 44 so as to seal against an internal surface 14a of the pumpable substance valve 30 adjacent the corresponding port 31. The valve body 40 can also include an O-ring 45 around the internal portion 42 that seals against an internal surface 32 of the port 31.

An advantage of a valve body 40 having two seals the flexible seal 43 and the O-ring 45) is that the seals reduce the likelihood that the pumpable substance will flow past the valve body when the valve body is in the closed position. For example, the two seals may reduce the likelihood that the pumpable substance will escape past the outlet valve body 40b and enter the outlet port 31 b when the outlet valve body 40b is in the closed position and the pumpable substance is pressurized. Such a condition is undesirable because the escaping pumpable substance may not be fully pressure processed, and may therefore contaminate the fully processed substance that subsequently passes through the open outlet port 31b. Furthermore, the two seals on the inlet valve body 40a may prevent unpressurized pumpable substance from passing out of the inlet port 31a and directly into the outlet port 31b without being pressurized, for example when the inlet valve body 40a is in the closed position and the outlet valve body 40b is in the open position.

The valve body 40 can also include a purging zone 60 that may further reduce the likelihood that the fully processed pumpable substance will be contaminated with unprocessed or under-processed pumpable substance. As shown in Figure 2, the purging zone 60 can be positioned between the 0-ring and the flexible seal 43. The purging zone 60 can be further bounded by the internal portion 42 of the valve body 40 and by the inner surface 32 of the port 31. Purging fluid can enter the purging zone 60 through one or more orifices 58 located in the valve body 40 adjacent the purging zone. The orifices can be coupled to a source of purging fluid via a passage 51 in the valve stem 50. In one embodiment, the purging fluid can be the same fluid as is used to drive the valve piston 52. Accordingly, the purging fluid can enter the passage 51 via a passage entrance 57 when the valve body 40 is in the closed position and flow through RECEIVED TIME 30. MAR. 13:28 PRINT TIME 2. APR. 11:23 3-02;12:20PM;DAVIES COLLISON CAVE A- 1 1 6 the valve stem 50 to the purging zone 60. When the valve body 40 is in the open position, the valve piston 52 blocks the passage entrance 57, preventing the purging fluid from entering the passage 51 and therefore preventing the purging fluid from flowing freely into the pressure vessel While in the purging zone 60, the purging fluid, can entrain particles of unprocessed or under-processed pumpable substance that might enter the purging zone by escaping past the flexible seal 43 and/or the O-ring Accordingly, the purging zone 60 forms a fluid barrier between a region containing fully processed pumpable substance and a region containing unprocessed or only partially processed pumpable substance. For example, the purging zone 60 surrounding the outlet valve body 40b may prevent pumpable substance that has not been fully pressure processed from escaping the pressure vessel 15 before the processing cycle is complete. Furthermore, the purging zone 60 surrounding the inlet valve body 40a may prevent unprocessed pumpable S 15 substance from flowing past the inlet valve body and out through the outlet port 31 b when the outlet valve body 40b is opened to remove the pumpable substance from the vessel The purging fluid can exit the purging zone 60 through an exit S. channel 61 to convey unpressurized or under-pressurized pumpable substance away from the corresponding port 31. The exit channel 61 can include a check valve 62 that prevents the purging fluid from re-entering the purging zone when the pressure in the purging zone drops. For example, the check valve 62 can include a flexible elastomeric ring that expands in diameter away from the exit channel 61 to allow the purging fluid to escape, and collapses on the exit channel to prevent the purging fluid from re-entering the purging zone 60. The escaping purging fluid can pass into an annulus 64 and away from the pressure vessel 15 through a relief valve 63. The relief valve 63 can be adjusted to maintain a pressure in the annulus 64 that is low enough to allow the purging fluid to escape and high enough to prevent the pumpable substance from passing out of the pressure vessel 15 between the cylinder 12 and the pumpable substance valve RECEIVED TIME 30. MAR. 13:28 PRINT TIME 2. APR. 11:23 P:\OPER\Ad\292104)2 sp .do.16/10/02 -7- The purging fluid may include any suitable fluid that can drive the valve bodies back and forth and purge the pumpable substance from the purging zones 60. The purging fluid may also include a compound that contains iodine to clean and/or sanitize the surface adjacent the purging zone 60 as the purging fluid passes through the purging zone Alternatively, the purging fluid may be selected to contain any substance that cleanses the purging zone 60 without adversely affecting the characteristics of the pumpable substance.

Accordingly, the purging fluid may further reduce the likelihood that the fully pressure processed pumpable substance is contaminated by under-pressurized or unpressurized S•pumpable substance. In addition, the purging fluid may reduce the likelihood that 10 particulates (which might be included in the pumpable substance) will become lodged o "between the valve body 40 and the port 31 where they can prevent the valve body from fully closing.

Figure 3 is a detailed partial cross-sectional side elevation view of the high pressure valve 70 and high pressure conduit 71 shown in Figure 1. The high pressure conduit 71 15 can be coupled to a source of ultrahigh-pressure fluid to drive the piston 13 in the pressure vessel 15. The ultrahigh-pressure fluid can be supplied by a device such as a model No.

25X available from Flow International Corp. of Kent, Washington. Such devices are capable of generating pressures up to 55,000 psi; however, pressures higher or lower than this value may be suitable as well, so long as the pressure is sufficient to produce the desired effect on the pumpable substance.

The ultrahigh-pressure fluid is evacuated from the pressure vessel 15 through the low pressure port 72 as the pressure vessel is filled with the pumpable substance. The low pressure port 72 may be opened and closed with the low pressure valve body 40c in a manner similar to that discussed above with reference to the inlet and outlet valve bodies 40a and 40b shown in Figure 2. The low pressure valve body 40c, the valve stem 50, and the valve piston 52 shown in Figure 3 may be identical to the valve bodies, valve stems and valve pistons shown in Figure 2 to provide for commonality of parts. However, because the low pressure port 72 is not exposed to the pumpable substance, the high pressure valve 70 need not include a purging zone 60 (Figure 2) or an exit channel 61 (Figure 2).

As shown in Figure 3, the high pressure valve 70 can include a sealing flange P:\OPER\Ar0292104)2 spc.doc-6/0/I)2 -8that is sealably coupled to an internal surface 14b of the cylinder 12 to seal the high pressure valve 70 within the cylinder. The sealing flange 65 is spaced apart from the internal surface 14b to accommodate an O-ring 67 that sealably engages both the internal surface 14b and the flange 65. The high pressure valve 70 can also include an elastomeric seal 68 adjacent the O-ring, and an anti-extrusion ring 69 adjacent the elastomeric seal, both of which are seated against an aft surface 73 of the sealing flange 65. The elastomeric seal 68 may comprise a polymer, such as an ultra-high molecular weight polyethylene, and the anti-extrusion ring 69 may include a metal, such as bronze. The aft surface 73 of the sealing flange 65 may be inclined so that as the elastomeric seal 68 is forced aft in the 10 direction indicated by arrow A (for example, when the pressure vessel 15 is pressurized), the elastomeric seal 68 forces the anti-extrusion ring 69 outward toward the cylinder 12, to prevent the elastomeric seal 68 from extruding into a small gap that might exist between the high pressure valve 70 and the cylinder 12. This arrangement may be advantageous because it reduces wear on the elastomeric seal 68. A similar arrangement may be used to seal the pumpable substance valve 30 (Figure 2) to the cylinder 12.

Operation of the apparatus 10 is best understood with reference to Figures 1 and 2.

Beginning with Figure 2, the outlet valve body 40b is closed by supplying purging fluid through the corresponding closing port 53. The purging fluid acts against the rear face of the corresponding valve piston 52 to draw the outlet valve body 40b into the outlet port 31 b. The O-ring 45 seals against the internal surface 32 of the port 31 and the flexible seal 43 seals against the internal surface 14a of the pumpable substance valve 30. The purging fluid enters the purging zone 60 of the outlet valve body 40b through the corresponding purging fluid passage 51, and exits the purging zone through the corresponding exit channel 61. The purging fluid continues to flow as long as the outlet valve body is in the closed position. The inlet valve body 40a is then moved to its open position by applying purging fluid to the corresponding opening port 54. The purging fluid acts against the forward face 55 of the corresponding valve piston 52 to drive the inlet body 40a to the open position.

Referring now to Figure 1, the low pressure valve body 40c is moved to its open position in a manner similar to that discussed above with reference to the inlet valve body The pumpable substance is then introduced through the inlet port 31a and into P:\OPER\AI21014)02 spe doc- 1611002 -9pressure vessel 15 to move the piston 13 toward the high pressure valve 70, driving residual high pressure fluid located between the piston 13 and the high pressure valve out through the low pressure port 72. The low pressure valve 40c and the inlet valve body are then closed and the ultrahigh-pressure fluid is introduced to the pressure vessel through the high pressure conduit 71. The ultrahigh-pressure fluid drives the piston 13 toward the pumpable substance valve 30 to compress the pumpable substance within the vessel. When the desired pressure is obtained, the flow of ultrahigh-pressure fluid is halted o and the pumpable substance is allowed to remain at an elevated pressure for a selected period oftime. When the selected period of time has elapsed, the pressure within the 10 pressure vessel 15 is relieved by initially passing the ultra-high pressure fluid out of the pressure vessel 15 through the high pressure conduit 71. The valve bodies 40b and 40c are then opened and low pressure fluid is supplied through the low pressure port 72 to move the piston 13 toward the outlet valve body 40b and remove the pumpable substance from S. the pressure vessel 15 through the outlet port 3 lb. The cycle can then be repeated with a new quantity of pumpable substance.

S° One advantage of the apparatus 10 shown in Figures 1-3 is that the plurality of seals on each valve body 40 reduces the likelihood that the pressure processed pumpable substance will become contaminated with unpressurized or under-pressurized pumpable o substance. Another advantage is that the two seals may define a purging zone 60 between the fully pressurized pumpable substance and the unpressurized pumpable substance. A purging fluid may be passed through the purging zone 60 to remove under-pressurized pumpable substance from the purging zone, creating a fluid barrier between the pressurized pumpable substance and the unpressurized or under-pressurized pumpable substance. Furthermore, the purging fluid sanitizes the surfaces of the apparatus in the purging zone. Both the purging function and the sanitizing function can be completed while the apparatus is pressurized and without having to access the interior of the pressure vessel Yet another advantage of the apparatus 10 shown in Figures 1-3 is that the seal 68 between the cylinder 12 and the valves 30 and 70 may include an anti-extrusion ring 69 positioned adjacent an inclined surface of the valves. The anti-extrusion ring 69 moves outward under pressure to reduce wear on the seal and to reduce the likelihood of a leak P:\OPER\ArlU92104)2 spe.doc-16/10/02 developing between the cylinder 12 and the valves 30 and 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 flexible seal 43 and the O-ring 45 can be arranged differently on the valve body 40 so long as they provide a purging zone 60 between the pressurized pumpable substance and the unpressurized or under-pressurized pumpable substance. Alternatively, the two seals alone (without the purging fluid) can be sufficient to isolate the pressurized pumpable substance. Where the purging fluid is provided, the purging fluid can be delivered to the 10 purging zone 60 via the valve stem 50, as shown in Figures 1-3, or alternatively, the °purging fluid can be supplied directly through the inner surface 32 of the port 31. In still a *further alternative, the piston 13 can be replaced with another pressurizing means, for example, a bladder or a bellows, that expands and contracts within the pressure vessel to pressurize the pumpable substance and to isolate the pumpable substance from the high pressure fluid. Accordingly, the invention is not limited except as by the appended claims.

Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

The reference to any prior art in this specification is not, and should not be taken as, an acknowledgment or any form of suggestion that that prior art forms part of the common general knowledge in Australia.

Claims (14)

1. An apparatus for pressure-processing a pumpable substance, comprising: a pressure vessel having an internal surface and at least one port through the internal surface; a valve body disposed in the port and movable relative to the port between an open position and a closed position, the valve body having at least one sealing surface that seals the port and at least restricts motion of the pumpable substance through the port when the S• valve body is in the closed position, the valve body having a channel with a first opening 10 coupled to a source of purging fluid and a second opening proximate to the port to direct purging fluid into a purging zone adjacent the valve body. 99

2. The apparatus of claim 1 wherein the pressure vessel includes a cylindrical portion having an open end and a pumpable substance valve positioned in the open end, the internal surface of the pressure vessel including an internal wall of the cylinder and an S internal wall of the pumpable substance valve, the one port extending through the internal wall of the pumpable substance valve. The apparatus of claim 1 or 2 wherein the valve body has first and second spaced apart seals that engage at least one of the internal surface of the pressure vessel and an internal surface of the port, the first opening of the valve body being between the seals, the valve body being spaced apart from at least one of the internal surfaces in the purging zone, further wherein the pressure vessel has a fluid exit channel in fluid communication with the purging zone to remove the purging fluid from the purging zone.

4. The apparatus of claim 3 wherein the exit channel is connected to a check valve that is movable relative to the exit channel between an open position wherein the check valve seals the exit channel to at least restrict motion of the purging fluid through the exit channel and an open position wherein the check valve opens the exit channel for the purging fluid to pass therethrough. P:\OPERMAf292 1042 sp.doc.-16O11i)2

12- The apparatus of claim 4 wherein the pressure vessel includes a cylindrical portion having an open end and a pumpable substance valve having a corresponding cylindrical wall positioned in the open end, further wherein the one port extends through the cylindrical wall of the pumpable substance valve, the exit channel extends through the cylindrical wall of the pumpable substance valve, and the check valve includes a resilient flexible ring disposed around the cylindrical wall of the pumpable substance valve and over an opening in the exit channel. oooo •*go S• 6. The apparatus of any one of claims 1 to 5 wherein the pressure vessel has an S. 10 interior volume, the port is coupled to a source of pumpable food substance, and the purging zone is located between the source of pumpable food substance and the interior volume of the vessel. 7. The apparatus of any one of claims 1 to 6, further comprising a valve piston coupled to the valve body and having first and second opposite faces, the first face being in .fluid communication with the source of purging fluid to move the valve body to the open position, the second face being in fluid communication with the source of purging fluid to move the valve body to the closed position. 8. The apparatus of claim 7, further comprising a stem that extends axially through the port between the valve body and the valve piston, wherein the channel extends through the stem. 9. The apparatus of any one of claims 1 to 8, further comprising the purging fluid, wherein the purging fluid is selected to sanitize at least a portion of the valve body and the port. The apparatus of claim 9 wherein the purging fluid contains iodine. 11. An apparatus for pressure-processing a pumpable substance, comprising: a pressure vessel having an internal surface and at least one port through the P:\OPER\ArI29210-2 spe.docI(lI/O2

13- internal surface; a valve body proximate to the port and movable relative to the port between an open position and a closed position, the valve body having at least one sealing surface that seals the port and at least restricts motion of the pumpable substance through the port when the valve body is in the closed position, the valve body having a channel with a first opening coupled to a source of purging fluid and a second opening proximate to the port to direct purging fluid into a region adjacent the valve body. 0*e@ 0 12. The apparatus of claim 11 wherein the valve body extends into to the port. 0 13. The apparatus of claim 12, further comprising a valve piston coupled to the valve body and having first and second opposite faces, the first face being in fluid communication with the source of purging fluid to move the valve body to the open position, the second face being in fluid communication with the source of purging fluid to 15 move the valve body to the closed position. 0000 ii00ii 14. A method for pressure processing a pumpable food substance, comprising: transferring the pumpable food substance into in an internal region of a pressure :0 vessel through a port of the pressure vessel; sealing the port by moving a valve body at least adjacent to the port to block flow through the port; purging a purging region located between the internal region of the pressure vessel and a source of the pumpable food substance by directing a purging fluid through an orifice in the valve body while the valve body blocks flow through the port. The method of claim 14 wherein sealing the port includes moving at least a portion of the valve body into the port.

16. The method of claim 14 or 15 wherein sealing the port of the pressure vessel includes applying the purging fluid to a piston connected to the valve body to urge the valve body adjacent to the port. P:OPERrlU292 I-042 spc.doc-16/10712 14-

17. The method of any one of claims 14 to 16, further comprising: selecting the purging fluid to have sanitizing properties; and sanitizing the purging region by directing the purging fluid into the purging region.

18. The method of claim 17 wherein sanitizing the purging region includes sanitizing a region adjacent an internal surface of the port.

19. The method of any one of claims 14 to 18, further comprising removing the purging fluid from the region adjacent to the valve body.

20. The method of any one of claims 14 to 19 wherein the act of purging includes mixing a portion of the pumpable food substance with the purging fluid in the purging region and removing the purging fluid and the portion of the pumpable food substance from the purging region.

21. The method of any one of claims 14 to 20, further comprising: sealably engaging the valve body with an internal surface of at least one of the pressure vessel and the port at two spaced apart locations; and directing the purging fluid between the two spaced apart locations.

22. The method of any one of claims 14 to 21, further comprising halting the flow of purging fluid through the orifice by moving the valve body away from the port to block the flow of purging fluid through the valve body. P:operadr\29210-02 spdc.do-21/l0)2 15

23. An apparatus substantially as described with reference to the drawings.

24. A method substantially as described with reference to the drawings. DATED this 21st day of October, 2002 FLOW INTERNATIONAL CORPORATION by its Patent Attorneys 10 DAVIES COLLISON CAVE 9*