IES960047A2 - Improvements in blast freezing - Google Patents
Improvements in blast freezingInfo
- Publication number
- IES960047A2 IES960047A2 IE960047A IES960047A IES960047A2 IE S960047 A2 IES960047 A2 IE S960047A2 IE 960047 A IE960047 A IE 960047A IE S960047 A IES960047 A IE S960047A IE S960047 A2 IES960047 A2 IE S960047A2
- Authority
- IE
- Ireland
- Prior art keywords
- belt
- compressed air
- snow
- blast freezing
- blast
- Prior art date
Links
- 238000007710 freezing Methods 0.000 title claims description 16
- 230000008014 freezing Effects 0.000 title claims description 15
- 238000010257 thawing Methods 0.000 claims abstract description 5
- 238000007664 blowing Methods 0.000 claims description 7
- 238000000034 method Methods 0.000 claims description 5
- 238000011144 upstream manufacturing Methods 0.000 claims description 3
- 238000009825 accumulation Methods 0.000 claims description 2
- 238000001914 filtration Methods 0.000 claims description 2
- 229910001220 stainless steel Inorganic materials 0.000 description 3
- 239000010935 stainless steel Substances 0.000 description 3
- 230000000694 effects Effects 0.000 description 2
- 230000004075 alteration Effects 0.000 description 1
- 230000001276 controlling effect Effects 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 230000001052 transient effect Effects 0.000 description 1
Classifications
-
- 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
- F25D13/00—Stationary devices, e.g. cold-rooms
- F25D13/06—Stationary devices, e.g. cold-rooms with conveyors carrying articles to be cooled through the cooling space
- F25D13/067—Stationary devices, e.g. cold-rooms with conveyors carrying articles to be cooled through the cooling space with circulation of gaseous cooling fluid
-
- A—HUMAN NECESSITIES
- A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
- A23B—PRESERVATION OF FOODS, FOODSTUFFS OR NON-ALCOHOLIC BEVERAGES; CHEMICAL RIPENING OF FRUIT OR VEGETABLES
- A23B2/00—Preservation of foods or foodstuffs, in general
- A23B2/80—Freezing; Subsequent thawing; Cooling
- A23B2/803—Materials being transported through or in the apparatus, with or without shaping, e.g. in the form of powders, granules or flakes
- A23B2/8033—Materials being transported through or in the apparatus, with or without shaping, e.g. in the form of powders, granules or flakes with packages or with shaping in the form of blocks or portions
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65G—TRANSPORT OR STORAGE DEVICES, e.g. CONVEYORS FOR LOADING OR TIPPING, SHOP CONVEYOR SYSTEMS OR PNEUMATIC TUBE CONVEYORS
- B65G45/00—Lubricating, cleaning, or clearing devices
- B65G45/10—Cleaning devices
- B65G45/22—Cleaning devices comprising fluid applying means
-
- 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
- F25D13/00—Stationary devices, e.g. cold-rooms
- F25D13/06—Stationary devices, e.g. cold-rooms with conveyors carrying articles to be cooled through the cooling space
-
- 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
- F25D21/00—Defrosting; Preventing frosting; Removing condensed or defrost water
- F25D21/06—Removing frost
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Mechanical Engineering (AREA)
- Physics & Mathematics (AREA)
- General Engineering & Computer Science (AREA)
- Thermal Sciences (AREA)
- Combustion & Propulsion (AREA)
- Life Sciences & Earth Sciences (AREA)
- Zoology (AREA)
- Polymers & Plastics (AREA)
- Food Science & Technology (AREA)
- Wood Science & Technology (AREA)
- Devices That Are Associated With Refrigeration Equipment (AREA)
- Cold Air Circulating Systems And Constructional Details In Refrigerators (AREA)
Abstract
An apertured blow pipe 2 is located above the return stretch of the mesh belt 1 in a blast freezer and is operable to deliver filtered compressed air to the surface of the belt 1 via the apertures. The compressed air blows away any snow which may have accumulated on the belt to a drain. The snow can thus be removed without need to shut down the blast freezer for defrosting. A regulator valve 3 is proveded to control the supply of compressed air to the apertures. <Fig. 1>.
Description
The present invention relates to an apparatus and method for blast freezing with particular regard to reducing maintenance down-time in a blast freezing apparatus.
Blast freezing is achieved by blowing air whose temperature is below 0°C about an object to be frozen. It is possible to use blast freezing to freeze objects which are on a conveyor, by passing the conveyor through the a cold air stream in, for example, a spiral freezer. Such apparatus includes an endless travelling stainless steel belt onto which the objects to be frozen are transferred. The belt is usually made of mesh material and the cold air is blown against the mesh.
A problem associated with such apparatus is that moisture in the air entering the freezer also freezes and this builds up as snow on the mesh belt. The snow restricts air flow through the mesh belt and thereby also reduces the cooling air flow over the product, elongating the freezing time. To eliminate the snow build-up, the freezer must be shutdown and defrosted. This is a costly exercise and necessitates stoppage of production for several hours until the defrosting cycle is completed.
It is an object of the present invention to alleviate the above disadvantages by providing a method and apparatus for reducing snow build-up in a blast freezer.
Accordingly, the present invention provides a blast freezing apparatus including an endless conveyor belt and means for circulating cold air about the belt to freeze products disposed thereon, characterised in that the apparatus includes blowing means disposed adjacent -the — SPECTION mJ OPEN TO PUP' SECTION 28 AND RULE 23 JNL. No.....(3:8¾.......OF^^/V^ •Him 7 ’ belt for directing compressed air onto the belt to displace snow which has accumulated on the belt.
The invention also provides a method of defrosting a blast freezing apparatus of the type described above, comprising directing compressed air onto a surface of the belt which has an accumulation of snow on it to blow the snow off the belt.
Advantageously, the blowing means comprises a tube having a plurality of bore holes arranged in a row along its longitudinal axis for releasing compressed air supplied within the tube.
The apparatus may includes regulator means for controlling the supply of compressed air to the blowing means and optionally including filter means upstream of the bore holes for filtering the compressed air.
The invention will now be described more particularly with reference to the accompanying Figure 1, which is a perspective view showing, by way of example only, one embodiment of a blast freezing apparatus according to the invention.
In the figure, a section of the interior of a blast freezer is shown, including a travelling stainless steel mesh belt 1. The feed stretch of the belt, at which product is collected and blast frozen is shown by the arrow A. The return stretch is shown by arrow B.
As product is introduced onto the belt, external air inevitably also enters the blast freezer. Any moisture in this air freezes very quickly and under the influence of the cold air flowing onto the belt to freeze the product, ^•00847 the resulting snow is blown against the mesh belt, where it is trapped, impeding free air flow.
Suspended above the return stretch on the belt 1 is a pipe 2 for receiving compressed air from a compressor (not shown). A valve 3 is provided for regulating the supply of compressed air to the pipe 2. A series of holes 4 are provided spaced apart on the underside of the pipe for directing compressed air onto the return stretch of the belt 1. On opening the valve 3, any snow which has accumulated on the belt 1 is blown from the belt 1 by compressed air emerging from the holes 4 and onto a floor drain. The pipe 2 is manufactured from 25 mm diameter stainless steel tube with a series of 1.5 mm holes 4 drilled at 10 mm spacing to provide outlets for the compressed air. A filter is provided upstream of the valve 3 to filter the compressed air. For food-freezing applications, a filter of 40 urn pore size is suitable.
The bore holes 4 may be fitted with nozzles if required. However, the provision of nozzles tends to increase the noise generated and may therefore preferably be used only in areas not frequented by personnel.
The blow pipe 2 may be operated from time to time as required by a build-up of snow on the belt 1. One pass of the entire belt 1 is usually sufficient to remove all accumulated snow. Alternatively, the blow pipe 2 may be operated continuously. As the compressed air from the blow pipe 2 is directed onto the return stretch of the belt 1, it does not affect the product or its freezing.
The temperature of the compressed air will normally be about 10°C and although this has a small heating effect on the belt 1, this effect is transient and does not affect the freezing properties of the blast freezer to any appreciable extent.
It will of course be understood that the invention is not limited to the specific details described herein, which are given by way of example only, and that various modifications and alterations are possible within the scope of the invention as defined in the appended claims.
Claims (5)
1. Blast freezing apparatus including an endless conveyor belt and means for circulating cold air about the belt to freeze products disposed thereon, characterised in that the apparatus includes blowing means disposed adjacent the belt for directing compressed air onto the belt to displace snow which has accumulated on the belt.
2. A method of defrosting a blast freezing apparatus of the type claimed in Claim 1, comprising directing compressed air onto a surface of the belt which has an accumulation of snow on it to blow the snow off the belt.
3. The invention as claimed in Claim 1 or 2, in which the blowing means comprises a tube having a plurality of bore holes arranged in a row along its longitudinal axis for releasing compressed air supplied within the tube.
4. The invention of Claim 3, including regulator means for controlling the supply of compressed air to the blowing means and optionally including filter means upstream of the bore holes for filtering the compressed air.
5. Blast freezing apparatus according to Claim 1 or a method of defrosting a blast freezing apparatus according to Claim 2, substantially as herein described with reference to or as shown in the accompanying drawing.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| IE960047A IES960047A2 (en) | 1996-01-19 | 1996-01-19 | Improvements in blast freezing |
| GB9700891A GB2309293B (en) | 1996-01-19 | 1997-01-17 | A conveyor apparatus for blast freezing |
| IE970034A IE970034A1 (en) | 1996-01-19 | 1997-01-17 | Improvements in blast freezing |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| IE960047A IES960047A2 (en) | 1996-01-19 | 1996-01-19 | Improvements in blast freezing |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| IES68332B2 IES68332B2 (en) | 1996-06-12 |
| IES960047A2 true IES960047A2 (en) | 1996-06-12 |
Family
ID=11041042
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| IE960047A IES960047A2 (en) | 1996-01-19 | 1996-01-19 | Improvements in blast freezing |
| IE970034A IE970034A1 (en) | 1996-01-19 | 1997-01-17 | Improvements in blast freezing |
Family Applications After (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| IE970034A IE970034A1 (en) | 1996-01-19 | 1997-01-17 | Improvements in blast freezing |
Country Status (2)
| Country | Link |
|---|---|
| GB (1) | GB2309293B (en) |
| IE (2) | IES960047A2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2792716B1 (en) * | 1999-04-20 | 2001-07-06 | Serap Industries | CRYOGENIC TUNNEL |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4173127A (en) * | 1977-11-02 | 1979-11-06 | Formax, Inc. | Frost removal apparatus for cryogenic freezing tunnel |
| US5203820A (en) * | 1992-03-06 | 1993-04-20 | Frigoscandia Food Process Systems Ab | Food freezing apparatus |
-
1996
- 1996-01-19 IE IE960047A patent/IES960047A2/en not_active IP Right Cessation
-
1997
- 1997-01-17 IE IE970034A patent/IE970034A1/en not_active IP Right Cessation
- 1997-01-17 GB GB9700891A patent/GB2309293B/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| IES68332B2 (en) | 1996-06-12 |
| GB2309293B (en) | 1999-12-22 |
| IE970034A1 (en) | 1997-07-30 |
| GB2309293A (en) | 1997-07-23 |
| GB9700891D0 (en) | 1997-03-05 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MM4A | Patent lapsed | ||
| MM4A | Patent lapsed |