US3600901A - Gas balance control in flash freezing systems - Google Patents

Gas balance control in flash freezing systems Download PDF

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Publication number
US3600901A
US3600901A US807491A US3600901DA US3600901A US 3600901 A US3600901 A US 3600901A US 807491 A US807491 A US 807491A US 3600901D A US3600901D A US 3600901DA US 3600901 A US3600901 A US 3600901A
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chamber
gas
path
refrigerant gas
plenum chamber
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Expired - Lifetime
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US807491A
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English (en)
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Richard C Wagner
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Integral Process Systems Inc
INTEGRAL PROCESS SYST Inc
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INTEGRAL PROCESS SYST Inc
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25D—REFRIGERATORS; COLD ROOMS; ICE-BOXES; COOLING OR FREEZING APPARATUS NOT OTHERWISE PROVIDED FOR
    • F25D3/00—Devices using other cold materials; Devices using cold-storage bodies
    • F25D3/10—Devices using other cold materials; Devices using cold-storage bodies using liquefied gases, e.g. liquid air
    • F25D3/11—Devices using other cold materials; Devices using cold-storage bodies using liquefied gases, e.g. liquid air with conveyors carrying articles to be cooled through the cooling space

Definitions

  • a gas balance method and device are provided in a system for flash freezing in which a high velocity refrigerant gas circulates into, through and out of an'open ended tunnel and it is desired to keep refrigerant gas loss through the ends of the tunnel at a minimum without permitting the entry of warm air into the system.
  • the circulation system includes a fan having an inlet and an outlet connected respectively to different points spaced along the length of the tunnel, the outlet being connected through a plenum chamber parallel to the tunnel; and the gas balance is achieved by an adjustable passage from the plenum chamber to the tunnel which permits a portion of the circulating refrigerant gas to short circuit its full circulation path.
  • the recirculation path includes passage through a pump, or fan, outside of the tunnel, or chamber; and the passage through the chamber, or portion thereof, may be countercurrent, concurrent or crosscurrent to the passage of the food articles along the conveyor.
  • This invention is applicable to systems in which a part of the gas recirculation path is through a plenum chamber which is adjacent to the flash-freezing process path.
  • means are provided for withdrawing a portion of the refrigerant gas from the recirculation path (or from each recirculation path when there is a plurality of them) in order to accommodate the freshly generated gas being added to the system by vaporization. And since the amount of gas being vaporized depends on the load of food articles passing through the tunnel and is thus variable, the amount of refrigerant gas being withdrawn must be adjusted to meet the changing load.
  • a portion of the recirculating gas is short circuited by passage of said portion from the plenum chamber to the process path so that it does not travel the full length of either and a change in the load in the system produces a change in the portion of gas being short circuited.
  • said portion of diverted gas enters the process path and meets the onfiowing main stream of circulating gas, it creates turbulence and eddy currents and slows down the net velocity of the main stream toward the fan inlet. Further, since a portion of the circulating gas travels a shorter path, the same fan capacity can be satisfied by a smaller amount of circulating gas.
  • the amount of gas diverted from the main stream is controlled by an adjustable opening between the plenum chamber and the process path; and this in turn is controlled by the temperature at the exit end of the tunnel.
  • a temperature-sensing device at the exit end of the tunnel is maintained at a temperature-offrom about 1 0 F. to about +10 F indicating a slight purge of nitrogen gas.
  • the temperature-sensing device activates a control mechanism which in turn activates a motor operating to close the adjustable passage and thereby reduce or cut off the diverted gas flow.
  • a rise in temperature serves to open the adjustable passage and increase the gas flow therethrough.
  • the flash-freezing chamber 11 consists of a precooling section 12, a freezing section 13 and a postcooling, or equalization section 14.
  • the precooling and postcooling sections have double walls 16 and 17, respectively, filled with a lightweight insulating material such as foamed polystyrene or polyurethane.
  • the freezing section has double walls 18 having a high vacuum between the inner and outer walls.
  • a conveyor system having three reaches 19, 21 and 22 is provided to provide passage through the chamber for food articles 24 from inlet end 26 to outlet end 27.
  • the terms upstream" and downstream as used herein are related to the direction of the food articles on the conveyor.
  • Liquid nitrogen is supplied to the chamber by a system described in detail in copending application Ser. No. 487,359, filed Sept. 15, 1965, by John D. Harper, Frederick Breyer and Richard C. Wagner.
  • the liquid nitrogen system comprises an insulated liquid nitrogen storage vessel 28 containing liquid nitrogen 29, a cryogenic pump 31 suspended in submerged relation in the liquid nitrogen in the vessel, a drive motor 32 mounted externally of the vessel and having a drivebelt 33 connected to the exposed upper end of the pump drive shaft 34.
  • the pump 31 is illustrated as being of the centrifugal type and is fully described in U.S. Pat. No. 3,379,132, issued Apr. 23, 1968 to Richard C. Wagner.
  • the discharge end of pump 31 leads through line 36 and valve 37 to manifold 38 to which a plurality of nozzles 39 are mounted so that liquid nitrogen sprayed through the nozzles will contact the food articles 24 passing thereunder, resulting in the vaporization of at least a portion of the nitrogen.
  • Excess liquid nitrogen collects in pan 41 and is drawn off by filtered drain 42 for return to vessel 28 and recycle.
  • Fresh liquid nitrogen to replace the liquid vaporized in the chamber is supplied by lines 43 and 66 and passes through solenoid valve 67 and regulating valve 48 into tray 41.
  • the solenoid valve is controlled by level sensing device 68 in the nitrogen return vessel and is actuated to on or off position by the level of liquid nitrogen in the vessel.
  • Regulating valve 48 controls the flow through line 66 when the solenoid valve is open.
  • the solenoid valve 67 may be bypassed in the event of malfunction by passing the liquid nitrogen through line 46 and valve 47.
  • valve 44 is provided to enable liquid nitrogen to be passed directly to the nozzles, as required in the startup operation.
  • the liquid nitrogen vaporized in the zone under the nozzles 39 passes into the gas contact zone moving countercurrently to the food articles as shown by the arrows.
  • the temperature of the freshly generated nitrogen is lower than the temperature of the circulating nitrogen so that some of it will move along the bottom of the chamber, below baffle 50. Also, some of the freshly generated nitrogen will blend with the recirculating nitrogen deflected by baffle 51 after passage through plenum chamber 52, the combined stream moving toward the chamber inlet above the baffle 50, impelled by the suction of fan 53.
  • the baffle 50 serves to restrict the cross-sectional area of the recirculating nitrogen and thus increase its velocity.
  • Fan inlet 54 draws gaseous nitrogen into the fan from both the recirculating stream above baffle 50 and the freshly generated stream below the baffle.
  • the gas drawn into the fan inlet passes to the fan through a conduit (not shown) behind the chamber.
  • L-shaped gate 56 which is movable by means of rod 57 projecting through the insulated wall, regulates the amount of recirculating gas and the amount of freshly generated gas going into the fan inlet. Movement of the rod and gate toward the right as shown in the FIGURE reduces the amount of recirculation gas moving into the fan inlet, sending more gas to the precooling section, and also increases the amount of freshly generated gas going into the fan inlet from the bottom of the chamber.
  • passage 58 is provided through the wall separating plenum chamber 52 from the remainder of the chamber, and the width of passage 58 is controlled by adjustable baffle 59 which is attached to rod 61 actuated by motor 62.
  • Motor 62 is controlled by a control mechanism, shown schematically at 63, in response to a temperature sensing device 64 at the exit end of the chamber.
  • gate 56 is adjusted to provide a balanced gas flow while baffle 59 is closed and the apparatus is under full load. At a balanced gas flow, there is no ingress of ambient air into the exit end of the chamber and there is a slight purge of nitrogen outward, as indicated by a desired temperature of about l F. to about F. at the temperature-sensitive element 64.
  • gate 56 remains untouched in the same position and all adjustments necessary to accommodate for lesser loads are carried out by the raising or lowering of baffle 59 in response to temperature fluctuations at element 64.
  • baffle 59 is in its most elevated position.
  • the amount of gas travelling the full recirculation path to baffle 51 and back is reduced; and most of the gas follows the short path through passage 58.
  • a shorter average gas path is provided and the time interval for recirculation of an average aliquot portion of the gas is reduced.
  • the full capacity of the recirculating fan is thereby satisfied by a greater number of cycles of a smaller amount of gas; and the smaller amount of gas required in the recirculation system compensates for the smaller amount of gas being vaporized by the lesser load.
  • an apparatus for flash freezing of articles comprising a hollow housing structure defining a substantially thermally isolated process chamber, means including a conveyor operating in said chamber for transporting articles in succession along a process path leading into, through and out of said chamber, means for contacting a cryogenic liquid with each article at a certain region along said process path to flash said liquid at least partially to gas for freshly generating refrigerant gas within said chamber, means defining a plenum chamber adjacent to said process path upstream of cryogenic liquid contact region, pumping means having a suction inlet commusaid plenum chamber to develop a high-velocity stream travel- 7 ing along a recirculation flow ⁇ path through said chamber from said discharge outlet, throug said plenum chamber to said suction inlet, the improvement which comprises passage means in said plenum chamber between said first andsecond portions of said process path and communicating with said suction inlet, a control element adjacent said passage means, and means for adjusting the position of said control element relative to said passage means, whereby when said control element completely
  • baffle means are provided below and parallel to said conveyor to provide for higher velocity of said refrigerant gas stream.
  • cryogenic liquid is liquid nitrogen.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Physics & Mathematics (AREA)
  • Mechanical Engineering (AREA)
  • Thermal Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Freezing, Cooling And Drying Of Foods (AREA)
  • Separation By Low-Temperature Treatments (AREA)
US807491A 1969-03-17 1969-03-17 Gas balance control in flash freezing systems Expired - Lifetime US3600901A (en)

Applications Claiming Priority (1)

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US80749169A 1969-03-17 1969-03-17

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US3600901A true US3600901A (en) 1971-08-24

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US (1) US3600901A (enrdf_load_stackoverflow)
DE (1) DE2012374A1 (enrdf_load_stackoverflow)
GB (1) GB1234368A (enrdf_load_stackoverflow)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3881322A (en) * 1971-11-19 1975-05-06 Air Liquide Method of cooling products
US4056950A (en) * 1976-05-25 1977-11-08 Dca Food Industries, Inc. Food processor with an air balancing system
US4229947A (en) * 1979-08-06 1980-10-28 Air Products And Chemicals, Inc. Cryogenic freezer
US4414819A (en) * 1981-05-08 1983-11-15 L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Temporarily rigidifying soft materials
US4757691A (en) * 1986-06-18 1988-07-19 Carboxyque Francaise Cooling process and tunnel
EP0309319A1 (fr) * 1987-09-21 1989-03-29 L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Installation de refroidissement d'un produit extrudé en continu
WO1991008430A1 (en) * 1989-11-29 1991-06-13 Frigoscandia Food Process Systems Ab Air treatment plant and method for a flow reduction therein
EP0617247A1 (fr) * 1993-03-26 1994-09-28 L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Dispositif de recyclage d'un liquide cryogénique et son application à un appareil de congélation de produits
US20100319365A1 (en) * 2007-11-27 2010-12-23 Newman Michael D Cross flow tunnel freezer system
US8333087B2 (en) 2007-08-13 2012-12-18 Linde, Inc. Cross-flow spiral heat transfer system
GB2562301A (en) * 2017-05-12 2018-11-14 Linde Ag Cryogen system, apparatus and method of providing a cryogen under pressure for sanitising a carcass

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2257240B (en) * 1991-06-25 1995-01-11 Boc Group Plc Apparatus for chilling

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3345828A (en) * 1965-06-11 1967-10-10 Air Prod & Chem Parallel flow cryogenic freezer
US3403527A (en) * 1967-06-01 1968-10-01 Air Prod & Chem Transverse-parallel flow cryogenic freezer
US3413818A (en) * 1963-12-13 1968-12-03 Fmc Corp Immersion freezing

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3413818A (en) * 1963-12-13 1968-12-03 Fmc Corp Immersion freezing
US3345828A (en) * 1965-06-11 1967-10-10 Air Prod & Chem Parallel flow cryogenic freezer
US3403527A (en) * 1967-06-01 1968-10-01 Air Prod & Chem Transverse-parallel flow cryogenic freezer

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3881322A (en) * 1971-11-19 1975-05-06 Air Liquide Method of cooling products
US4056950A (en) * 1976-05-25 1977-11-08 Dca Food Industries, Inc. Food processor with an air balancing system
US4229947A (en) * 1979-08-06 1980-10-28 Air Products And Chemicals, Inc. Cryogenic freezer
EP0024159B1 (en) * 1979-08-06 1983-11-30 Air Products And Chemicals, Inc. Cryogenic freezer
US4414819A (en) * 1981-05-08 1983-11-15 L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Temporarily rigidifying soft materials
US4757691A (en) * 1986-06-18 1988-07-19 Carboxyque Francaise Cooling process and tunnel
EP0309319A1 (fr) * 1987-09-21 1989-03-29 L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Installation de refroidissement d'un produit extrudé en continu
AU639795B2 (en) * 1989-11-29 1993-08-05 Frigoscandia Food Process Systems Ab Air treatment plant and method for a flow reduction therein
WO1991008430A1 (en) * 1989-11-29 1991-06-13 Frigoscandia Food Process Systems Ab Air treatment plant and method for a flow reduction therein
US5247801A (en) * 1989-11-29 1993-09-28 Frigoscandia Food Process Systems A.B. Air treatment plant and method for a flow reduction therein
EP0617247A1 (fr) * 1993-03-26 1994-09-28 L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Dispositif de recyclage d'un liquide cryogénique et son application à un appareil de congélation de produits
FR2703139A1 (fr) * 1993-03-26 1994-09-30 Air Liquide Dispositif de recyclage d'un liquide cryogénique et son application à la congélation de produits.
US5419140A (en) * 1993-03-26 1995-05-30 L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Device for recycling a cryogenic liquid and its use in an apparatus for freezing products
US8333087B2 (en) 2007-08-13 2012-12-18 Linde, Inc. Cross-flow spiral heat transfer system
US20100319365A1 (en) * 2007-11-27 2010-12-23 Newman Michael D Cross flow tunnel freezer system
GB2562301A (en) * 2017-05-12 2018-11-14 Linde Ag Cryogen system, apparatus and method of providing a cryogen under pressure for sanitising a carcass
GB2562301B (en) * 2017-05-12 2020-02-26 Linde Ag Cryogen system providing a cryogen under pressure for sanitising a carcass

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Publication number Publication date
DE2012374A1 (de) 1970-10-01
GB1234368A (enrdf_load_stackoverflow) 1971-06-03

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