GB2563410A

GB2563410A - Cryogen refinement apparatus, method of refining a cryogen, heat exchange arrangement and method of cooling by heat exchange

Info

Publication number: GB2563410A
Application number: GB1709453.3A
Authority: GB
Inventors: Hipkin Richard
Original assignee: Linde GmbH
Current assignee: Linde GmbH
Priority date: 2017-06-14
Filing date: 2017-06-14
Publication date: 2018-12-19
Anticipated expiration: 2037-06-14
Also published as: GB2563410B; GB201709453D0

Abstract

A cryogen refinement apparatus comprises a fluid conduit 102 carrying therein a cryogen comprising a vapour phase portion and a liquid phase portion. A phase separator device 106, 110 is sealingly and externally coupled to an end 108, 112 of the fluid conduit, and removes the vapour phase portion from the liquid phase portion to deplete the cryogen of the vapour phase portion. The phase separation device may comprise a vent device which may comprise a float (202, fig 2) to facilitate venting, and may be a float steam trap device. The phase separation device may be sealingly and externally coupled to both ends of the fluid conduit. Also disclosed is a heat exchanger (401, fig 4) used to vaporise a portion of the cryogen and has an inlet port (402, fig 4), and an outlet port (408, fig 4) in fluid communication with the cryogen refinement apparatus. A method for dispensing cryogen for sanitising a carcass comprises the method of using the cryogen refinement apparatus and uses a plurality of nozzles 104 in fluid communication with the fluid conduit is also disclosed.

Description

CRYOGEN REFINEMENT APPARATUS, METHOD OF REFINING A CRYOGEN, HEAT EXCHANGE ARRANGEMENT AND METHOD OF COOLING BY HEAT EXCHANGE [0001] The present invention relates to a cryogen refining apparatus of the type that, for example, treats two-phase flow in a cryogenic medium. The present invention also relates to a method of refining a cryogen, the method being of the type that treats two-phase flow in a cryogenic medium. The present invention also relates to a heat exchange arrangement of the type that, for example, generate a two-phase flow in a cryogenic medium. The present invention further relates to a method of cooling by heat exchange, the method being of the type that, for example, flows a cryogen through a heat exchanger producing a two-phase flow in a cryogenic medium.

[0002] It is, of course, known to use cryogens for applications requiring cooling and freezing, sometimes for processing foodstuffs. In this regard, an apparatus for sanitising a carcass, for example but not exclusively a poultry carcass, is known to provide a passageway in which a cryogen is ejected from an array of nozzles. The array of nozzles is fed cryogen from a so-called spray bar, which is a fluid conduit fed by a pressurised source of a cryogen, for example liquid nitrogen (N₂). Poultry carcasses are translated through the passageway, during which time some of the cryogen ejected from the nozzles impinges upon the carcass in order to reduce a population of bacteria, for example a species of bacteria, such as Campylobacter jejuni.

[0003] However, due to the level of vapour that develops in the fluid, for example, so-called two phase flow exists, which can cause operational problems in the known apparatus. Depending upon the apparatus’ tolerance for build-up of vapour, there is a risk that the apparatus will operate at suboptimal efficiency or even cease to operate completely. Such operational issues result in down-time of the apparatus, and requires costly technical support and site visits for maintenance and repair.

-2[0004] According to a first aspect (or embodiment) of the present invention, there is provided a cryogen refinement apparatus comprising: a fluid conduit capable of carrying therein a cryogen comprising a vapour phase portion and a liquid phase portion; and a phase separator device sealingly and externally coupled to an end of the fluid conduit, the phase separator device being arranged to remove, when in use, the vapour phase portion from the liquid phase portion so as to deplete the cryogen of the vapour phase portion.

[0005] The phase separator device may be a vent device.

[0006] The phase separator device may comprise a float therein to facilitate venting of the vapour phase portion from the liquid portion.

[0007] The apparatus may further comprise: a float steam type trap; the float steam type trap may have an inlet port sealingly coupled to the end of the fluid conduit and an outlet port in fluid communication with atmosphere.

[0008] The apparatus may further comprise: another phase separator device sealingly and externally coupled to another end of the fluid conduit.

[0009] The apparatus may further comprise: a spray bar comprising the fluid conduit; and an outlet nozzle for ejecting the cryogen therefrom. The outlet nozzle may be operably coupled to the fluid conduit.

[0010] The fluid conduit may comprise a plurality of outlet nozzles operably coupled thereto in spaced relation; the plurality of outlet nozzles may comprise the outlet nozzle.

[0011] The apparatus may further comprise: a heat exchanger apparatus; the heat exchanger apparatus may have an inlet port operably coupled to the fluid conduit at one end thereof.

[0012] According to a second aspect (or embodiment) of the present invention, there is provided a heat exchange arrangement comprising: a heat exchanger having an inlet port for receiving a cryogen, and an outlet port; wherein the outlet

-3port is in fluid communication with a cryogen refinement apparatus as set forth above in relation to the first aspect of the invention.

[0013] According to a third aspect (or embodiment) of the present invention, there is provided a method of refining a cryogen, the method comprising: flowing a cryogen through a fluid conduit, the cryogen comprising a vapour phase portion and a liquid phase portion; and phase separating the vapour phase portion from the liquid phase portion at an end of the fluid conduit so as to deplete the cryogen of the vapour phase portion.

[0014] Phase separating the vapour phase portion from the liquid phase portion may comprise coupling a phase separator to an end of the fluid conduit.

[0015] According to a fourth aspect (or embodiment) of the present invention, there is provided a method of dispensing a cryogen for sanitising a carcass, the method comprising: the method of processing a cryogen as set forth above in relation to the third aspect of the invention; and providing a plurality of nozzles operably coupled to the fluid conduit and arranged to eject cryogen therethrough.

[0016] According to a fifth aspect (or embodiment) of the present invention, there is provided a method of cooling by heat exchange, the method comprising: flowing a cryogen through a heat exchanger; and removing a vapour phase portion of the cryogen from a liquid phase portion of the cryogen using the method of processing a cryogen as set forth above in relation to the third aspect of the invention.

[0017] It is thus possible to provide an apparatus and method that obviates or at least mitigates two-phase flow in a cryogen. The removal or minimisation of the two-phase flow benefits efficiency and reliability of apparatus employing the cryogen refinement apparatus.

[0018] At least one embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0019] Figure 1 is a schematic diagram of a spray bar, which is an example of a cryogen processing apparatus constituting an embodiment of the invention;

-4[0020] Figure 2 is a schematic diagram of a phase separator device used in the apparatus of Figure 1;

[0021] Figure 3 is a flow diagram of a method of processing a cryogen constituting another embodiment of the invention; and [0022] Figure 4 is a schematic diagram of a heat exchange arrangement constituting a further embodiment of the invention.

[0023] Referring to Figure 1, a cryogen refinement apparatus 100 is shown generally and includes, for example a spray bar 101 comprising a fluid conduit 102 in fluid communication with a pressurised source (not shown) of cryogen, for example liquid nitrogen (LIN). A plurality of outlet nozzles 104 is operably coupled to the fluid conduit 102 so as to be in fluid communication with an internal volume of the fluid conduit 102. The plurality of nozzles 104 is disposed in spaced relation along a surface of the fluid conduit 102.

[0024] A first vapour separator device 106 is disposed at a first end 108 of the fluid conduit 102. In this example, the first vapour separator device 106 is a venting device, for example a float steam trap type device. In another embodiment, an inverted bucket type trap can be employed, but installed in a reverse orientation, i.e. upside-down orientation.

[0025] The first vapour separator device 106 is sealingly coupled to the first end 108 of the fluid conduit 102 and has an inlet port that is in fluid communication with the first end 108 of the fluid conduit 102.

[0026] In this example, a second vapour separator device 110 is disposed at a second end 112 of the fluid conduit 102. Although vapour separator devices 106, 110 are shown employed at both ends of the fluid conduit 102, this is optional and dependent upon application requirements. In this example, the second vapour separator device 110 is also a venting device, for example a float steam trap device. The second vapour separator device 110 is sealingly coupled to the second end 112 of the fluid conduit 102 and has an inlet port that is in fluid communication with the second end 112 of the fluid conduit 102.

-5[0027] Turning to Figure 2, the first and second vapour separator devices 106, 110, as described above, are in this example float steam trap type devices 106, 110, which are examples of continuous drainage, intermittent discharge, devices. The float steam type trap device 106, 110, oriented as described above, comprises a float 202 disposed within a main chamber 204 of a body 206. An inlet port 208 is provided and is in fluid communication with the main chamber 204 at a first distal end thereof. The inlet port 208 is fluidly coupleable to a source of cryogen, for example an end of the fluid conduit 102 of Figure 1. The float 202 is pivotally mounted, at one end thereof, to in internal distal end 210 of the inlet port 208, although any suitable pivot point can be employed. An outlet port 212 is provided at a second distal end of the main chamber 204, which in this example is used to vent vapour phase cryogen that is mixed with the liquid phase cryogen flowing through the spray bar 101.

[0028] In operation (Figure 3), cryogen flows (Step 300) into the spray bar 101 under pressure from the pressurised source of cryogen. Some of the cryogen flowing through the spray bar 101 boils and changes phase into vapour and so a two-phase flow develops in the spray bar 101. The first and second vapour separator devices 106, 110 serve to remove the vapour phase cryogen from the liquid phase cryogen. In this respect, the cryogen flows (Step 302) into each of the first and second vapour separator devices 106, 110 and the vapour phase cryogen is vented out of the outlet ports 212 of the first and second vapour separator devices 106, 110.

[0029] Referring to the float steam type trap 106, 110, a mixture of liquid phase and vapour phase cryogen enters the body 206 via the inlet port 208, which is in fluid communication with an end of the spray bar 101. The vapour-liquid mixture therefore resides in the main chamber 204. The mixture surrounds the float 202. The position of the float 202 within the main chamber 204 depends upon the balance of pressure exerted on the float 202 by the vapour phase cryogen versus the buoyancy provided by the liquid phase cryogen (Step 304). In this regard, the liquid phase cryogen beneath the float 202 buoys the float 202 and causes the float 202 to rise and block the outlet port 212 (Step 310) when insufficient vapour

-6phase cryogen resides in the main chamber 204. However, when sufficient vapour phase cryogen collects above the liquid phase cryogen in the main chamber 204, the pressure of the vapour phase cryogen on the float 202 is sufficient to overcome the buoyancy of the float 202 such that the float 202 is lowered, thereby opening (Step 306) the outlet port 212 and permitting the vapour cryogen in the main chamber 204 to escape (Step 308) through the outlet port 212 to vent to atmosphere.

[0030] Once the vapour phase cryogen has escaped through the outlet port 212, the force urging the float 202 upwards is greater than the pressure exerted on the float 202 by the vapour phase cryogen (Step 304) and the float 202 returns to being urged against the outlet port 212 (Step 310). Of course, more vapour phase cryogen will develop within the spray bar 101, and so this process repeats as vapour phase cryogen builds up in the main chamber 204 and thus the above process is continuous, portions of the vapour phase cryogen being repeatedly removed from the liquid phase cryogen. Consequently, the vapour phase cryogen is substantially removed from the liquid phase cryogen.

[0031] In the above example, the cryogen refinement apparatus 100 can be employed in a cryogen application apparatus for sanitising a carcass. Such an apparatus provides a passageway in which the spray bar 101 is disposed. Carcasses, for example poultry carcasses, are translated through the passageway while cryogen is dispensed from the outlet nozzles 104. The cryogen impinges upon the carcass and the heat transfer cools the surface of the carcass so as to kill bacteria living on the surface of the carcass. The cryogen refinement apparatus 100 serves to deplete the cryogen in the spray bar 101 of the vapour phase components so that the nozzles 104 dispense, as much as possible, liquid phase cryogen.

[0032] In another embodiment (Figure 4), a heat exchange assembly 400 comprises a heat exchanger 401 having an inlet port 402 in fluid communication with a liquid supply line 404, for example a supply line for a cryogen. The cryogen can be, for example, N₂, such as LIN. The heat exchange arrangement 400 also

-7comprises a discharge line 406 having a distal end in fluid communication with an outlet port 408 of the heat exchanger 401. A second distal end of the discharge line 406 is in fluid communication with a vapour separator device 410 of the type described above in relation to the previous embodiment of Figure 2.

[0033] In operation, a cryogen enters the heat exchanger 401 predominantly in liquid phase and passes through the heat exchange arrangement where a proportion of the liquid cryogen vaporises, resulting in a vapour-liquid mixture exiting the heat exchanger 401 at the outlet port 408. The vapour-liquid mixture flows through the discharge line 406 to the vapour separator device 410 where the vapour phase cryogen vents to atmosphere, for example, leaving the liquid phase cryogen. Although not shown in this example, the liquid phase cryogen can flow to any suitable location in a facility for any desired purpose, for example reuse or storage.

[0034] The skilled person should appreciate that the above-described implementations are merely examples of the various embodiments that are conceivable within the scope of the appended claims. Indeed, although in this example, nitrogen is described as the supply gas, any other kind of inert gas is contemplated.

[0035] Similarly, although an elongate spray bar 101 carrying an array of outlet nozzles 104 is described above, the skilled person should appreciate that other configurations of outlet nozzles employing the cryogen refinement apparatus are contemplated.

Claims

1. A cryogen refinement apparatus comprising:

a fluid conduit capable of carrying therein a cryogen comprising a vapour phase portion and a liquid phase portion; and a phase separator device sealingly and externally coupled to an end of the fluid conduit, the phase separator device being constructed and arranged to remove the vapour phase portion from the liquid phase portion to deplete the cryogen of the vapour phase portion.

2. An apparatus as claimed in Claim 1, wherein the phase separator device comprises a vent device.

3. An apparatus as claimed in Clam 1 or Claim 2, wherein the phase separator device comprises a float therein to facilitate venting of the vapour phase portion from the liquid portion.

4. An apparatus as claimed in any one of Claims 1 to 3, further comprising:

a float steam type trap having an inlet port sealingly coupled to the end of the fluid conduit, and an outlet port in fluid communication with atmosphere.

5. An apparatus as claimed in any one of the preceding claims, further comprising:

another phase separator device sealingly and externally coupled to another end of the fluid conduit.

6. An apparatus as claimed in any one of the preceding claims, further comprising:

a spray bar comprising the fluid conduit; and an outlet nozzle for ejecting the cryogen therefrom, the outlet nozzle being operably coupled to the fluid conduit.

7. An apparatus as claimed in Claim 6, wherein the spray bar comprises a plurality of outlet nozzles operably coupled thereto in spaced relation and in respective fluid communication with the fluid conduit.

8. An apparatus as claimed in any one of Claim 1 to 4, further comprising:

a heat exchanger apparatus, the heat exchanger apparatus having an inlet port operably coupled to and in fluid communication with the fluid conduit at one end thereof.

9. A heat exchange assembly comprising:

a heat exchanger having an inlet port for receiving a cryogen, and an outlet port; wherein the outlet port is in fluid communication with a cryogen refinement apparatus as claimed in Claim 1.

10. A method of refining a cryogen, the method comprising:

flowing a cryogen through a fluid conduit, the cryogen comprising a vapour phase portion and a liquid phase portion; and separating the vapour phase portion from the liquid phase portion at an end of the fluid conduit, thereby depleting the cryogen of the vapour phase portion.

11. A method as claimed in Claim 10, wherein the separating the vapour phase portion from the liquid phase portion comprises coupling a phase separator to an end of the fluid conduit.

12. A method of dispensing a cryogen for sanitising a carcass, the method comprising:

the method of refining a cryogen as claimed in Claim 10 or Claim 11; and providing a plurality of nozzles operably coupled to and in fluid communication with the fluid conduit and arranged to eject cryogen therethrough.

13. A method of cooling by heat exchange, the method comprising:

flowing a cryogen through a heat exchanger; and removing a vapour phase portion of the cryogen from a liquid phase portion of the cryogen using the method of refining a cryogen as claimed in Claim 10 or Claim 11.