JP2834722B2 - Vacuum cooling device with regenerator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum cooling apparatus, and more particularly to a special brine cooler for producing fine fluidized sherbet brine with ice and an ice-blind brine excellent in following a heat load fluctuation. The present invention relates to a vegetable vacuum cooling device equipped with a regenerator that can be efficiently cooled by providing the regenerator.

[0002]

2. Description of the Related Art Vegetables live and perform living functions after harvesting, but in order to maintain their freshness for a long time, it is important to suppress the respiratory action as soon as possible after harvesting. The best way to control respiratory action is to cool the vegetable temperature to near the freezing point. A vacuum cooling device is used for this cooling. By the way, water is 100 ° C at a pressure of 760 mmHg,
22 ° C at 20 mmHg in vacuum and 4 at 6 mmHg
Evaporate at ℃ to take out latent heat of evaporation of about 600 kcal / kg.
The vacuum cooling device is a device that uses a latent heat of vaporization of free water contained in the vegetables to collect and cool the vegetables by vacuum.
A typical non-thermal storage type vacuum cooling device currently used is shown in FIG. That is, the vegetables are stored and sealed in the vacuum chamber 1 and evacuated by the vacuum pump 8. 20m inside the vacuum chamber
At mHg, the free moisture of the vegetables at the product temperature of 22 ° C. starts to evaporate, the degree of vacuum increases, the evaporation is promoted, and the vegetables are cooled by latent heat of evaporation. When the inside of the vacuum chamber reaches 6 mmHg, the temperature of the vegetable becomes 4 ° C. When water evaporating from vegetables becomes gas, 1 liter of water is 6mmH under atmospheric pressure.
In the case of g, the volume becomes about 2,000,000 times, so that it is technically difficult to evacuate with a vacuum pump. Therefore, a cold trap 2 is provided, and the cold trap 2 is cooled to about −5 ° C. by a brine cooler 4, and the water vapor exhausted from the vacuum tank 1 and passed through is changed to water to be drained. Exhaust at A brine cooler 4 and a cold trap 2 are used for this purpose.

[0003]

The cooling cycle of vacuum cooling is about 25 minutes, of which the evaporation time of vegetable water is about 17 minutes. Since the heat load is applied in this short time, a large capacity brine cooler is required. If the capacity of the electrical equipment used increases, the electricity bill, especially the basic bill, becomes expensive. Vegetable cooling systems are only used for five months from June to October during the year, but half of the basic fee must be paid during the rest period. The annual electricity bill is therefore expensive and very uneconomical.

[0004]

SUMMARY OF THE INVENTION The present inventor has found that the above-mentioned problems can be solved by installing a regenerator in a vacuum cooling device in consideration of economical operation time of a refrigerator from the viewpoint of energy saving and the like. A vacuum cooling device provided with a regenerator has been proposed (Japanese Patent Application No. 59-207123 and Japanese Patent Application Laid-Open No. 61-86553). The apparatus is as shown in FIG. 3, and includes a vacuum pump 8 for evacuating a vacuum tank 1 for vacuum cooling vegetables, a cold trap 2 for condensing water vapor evaporating from vegetables, and a cold trap. In a vegetable vacuum cooling apparatus having a brine cooler 4 for cooling brine, a compressor 3 for a refrigerant circulating through the brine cooler, and a condenser 5 as main components, the brine circulating through the cold trap 2 is about -5 ° C. about 60% of the water content is frozen in
A cool storage tank 6 is provided between the brine cooler 4 and the cold trap 2. When the vegetables are vacuum cooled, the refrigerant from the condenser 5 passes through the refrigerant three-way valve 14b and is cooled by the brine cooler 4. The brine flows from the brine cooler 4 to the cold trap 2, the cold storage tank 6, and the brine cooler 4, and is condensed with water vapor evaporating from the vegetables in the cold trap 2. When the vacuum cooling device is stopped, the brine is retained in the cold storage tank 6, and the three-way valve 14b is switched so that the refrigerant from the condenser 5 flows to the cooling coil 17 installed in the cold storage tank 6, and the water content of the brine is reduced. It is a vegetable vacuum cooling device characterized in that about 60% of the vegetable is cooled to freeze.

According to the present invention, as a result of further research on this kind of vacuum cooling device, the brine cooling device has a specific structure, and the regenerator has a structure easy to melt ice. The inventors have found that the problem can be solved more easily and arrived at the present invention.
As described above, one operation step of vacuum cooling takes about 30 minutes, but only about 17 minutes need to cool the cold trap, and the work time per day is 5 hours. Therefore, when the vegetable cooling operation is stopped, that is, when the vacuum cooling operation is not performed, the brine cooler is operated by using the nighttime electric power with a low electricity rate, and the ice-containing sherbet brine of only -5 ° C to -3 ° C is generated. , which exclusively sends Hosokori the cold storage tank sequentially ice by floating, cold tiger during vacuum cooling operation
Cold storage tank where brine is circulated from the top to about 1 ℃
Cold about -5 ℃ ~-3 ℃ the brine in the brine cooler
Ice-mixed brine with around 60% of the water content
To a cold trap, which is used for cooling the cold trap. A specific thin ice block by this cool storage tank
By using the line, electric power can be used efficiently and vegetables can be cooled efficiently.

That is, according to the present invention, a vacuum pump 8 for evacuating a vacuum tank 1 for vacuum cooling vegetables, a cold trap 2 for condensing water vapor evaporating from vegetables, and a brine for circulating through the cold trap are cooled. A brine cooler 4, a compressor 3 for a refrigerant circulating through the brine cooler, and a condenser 5 are main components, and the brine cooler 4 and the cold trap 2 are provided.
In the vegetable vacuum cooling device in which the regenerator 6 is provided, the brine cooler 4 is composed of a super chiller having a special structure, and the inner pipe 17 through which the brine flows and the outer pipe through which the refrigerant having the refrigerant evaporation temperature of -10 ° C flows. And a blade 21 for scraping off crystal ice adhered and deposited on the inner surface of a cooling cylinder (inner tube) 17 inside the cylindrical body of the double tube 16 and the brine cooler at a high speed. 4 by circulating (cooling cylinder) within the inner tube 17 subcooled, scraped particles of ice adhering deposit on the inner surface of the inner tube 17, to generate the shear base Tsu you want to mix the brine and ice,
The warmed brine from the cold trap 2 and the cooling brine from the brine cooler 4 are introduced into the regenerator 6 by switching the three-way valve 14a. Flows through the expansion valve 15 to the brine cooler 4, and the brine in the regenerator 6 is introduced into the brine cooler 4 by the brine circulation pump 11 and cooled to about −5 ° C. to −3 ° C. to reduce the water content. 60% is a sherbet brine mixed with frozen ice particles, and then enters the cold trap 2,
The water vapor is condensed by heat exchange with vegetable steam, heated and flows to the cold storage tank 6 where the latent heat of melting of the stored ice melts to about 0%.
℃ plumbed so that, also when stopping vegetable vacuum cooling, brine three-way valve 14a switches the brine cooler 4 from the cold storage tank mixed to Shah base Ttoburain ice particles about 60% is frozen in the water content 6 The present invention relates to a vegetable vacuum cooling apparatus equipped with a cold storage tank, which is arranged so that thin ice is sequentially accumulated and cooled as described above. Calcium chloride,
Ethylene glycol, naive brine, etc. were used after cooling to about -10 ° C. Shimizu freezes and cools and uses latent heat, but brine does not freeze and use the latent heat, but exclusively uses sensible heat. However, when cooling in a cylinder having a jacket in which the refrigerant evaporates while rotating the brine at a high speed, the coolant is immediately cooled and supercooled, which has an excellent heat transfer rate. This brine is sent to the cylinder center, and freezing and the pressure drops, to produce ice particles, the shear base Tsu bets like brine. In the present invention, this phenomenon is used to advantage,
It uses the latent heat.

FIG. 1 shows an example of the vacuum cooling device of the present invention. In FIG. 1, 1 is a vacuum tank, 2 is a cold trap, 3 is a compressor, 4 is a brine cooler, 5 is a condenser, 6
Is a regenerator, 7 is a cooling tower, 8 is a vacuum pump, 9 is a brine pipe, 10 is a refrigerant pipe, 11 is a brine circulation pump,
2 is a cooling water pump, 13 is a cooling water pipe, 14a is a brine three-way valve, 15 is an expansion valve, 16 is a refrigerant jacket, 17
Is a brine cooling cylinder, and W is a drain drain.
When the apparatus of the present invention is operated, the aqueous brine solution is sucked from the regenerator 6 at about 1 ° C. into the brine circulation pump 11,
It is pushed into the brine cooler 4. 1 ° C brine is-
It is cooled to 5 ° C to -3 ° C and reaches cold trap 2.
The steam of 8 to 10 ° C evaporated from the vegetables is cooled and replaced with water to dehumidify. The brine which flows in at about -5 ° C to -3 ° C exchanges heat with vegetable steam and rises in temperature to 3 to 8 ° C.
Is sprayed. Brine melts the stored ice,
It is cooled to about 0 ° C to 1 ° C by the latent heat. The brine cooler 4 of the present invention has a structure as shown in FIGS. 5 and 6. FIG. 5 is a schematic cross-sectional view of the brine cooler 4, and FIG. 5 is a schematic view of a state where the scraping blade is attached. .

As shown in FIG. 5, the brine cooler 4 of the present invention comprises a double cylinder of a cooling cylinder (inner pipe) 17 and a jacket (outer pipe) 16 which is heat-insulated.
As shown in the figure, the cooling cylinder 17 has a blade 21 for scraping off crystal ice deposited and attached.

5 and 6, reference numeral 20 denotes a scraping blade mounting shaft, 21 denotes a scraping blade, 22 denotes a geared motor, 23 denotes a brine inlet, 24 denotes a brine outlet, and 2 denotes a brine outlet.
5 is a refrigerant inlet, 26 is a refrigerant outlet, 27 is a heat insulating material, 2
8 is a heat exchanger cover.

In the present invention, a liquid ice (sorbet brine) is generated by employing a super chiller having the above-described specific configuration as the brine cooler 4. Originally, ice has the property of freezing only water that does not contain impurities. By utilizing this characteristic, the brine cooler 4 of the present invention cools the aqueous brine solution inside from the outer peripheral portion to make it supercooled, obtains liquid ice having fluidity, and continuously crystal ice deposited and adhered to the inner surface. The ice is continuously produced while being scooped by scraping blades 21 made of a metal plate. If the supercooled aqueous solution is maintained as long as possible under the supercooled temperature condition, ice is generated, heat of solidification is released, and the temperature of the aqueous solution rises and balances. That is, crystallized spherical ice precipitates, and antifreeze material surrounds the ice to maintain the fluidity of the ice. The refrigerant R-22 that evaporates at −10 ° C. flows between the inner pipe 17 of the brine cooler 4 and the outer jacket 16, and the brine 19 flowing inward
To cool. The brine in the regenerator 6 is a circulation pump 11
As a result, the refrigerant is introduced into the inner pipe 17 of the brine cooler 4 (double-pipe inner-surface ice scraping heat exchanger) and supercooled by the refrigerant R-22 flowing through the outer pipe 16. At this time, fine crystal ice precipitates on the heat transfer surface (inner surface) of the inner tube 17. If left undisturbed, an ice layer is formed, heat transfer is impaired, and the circulation of brine is hindered.

In the present invention, the rotary shaft 20 having the scraping blades 21 as shown in FIG.
2 and the scraper blades 21 rotate the inner pipe 17.
The fine crystal ice adhering to the inner surface of the is scraped off. The scraping blade 21 is freely supported by the rotating shaft 20,
When the rotating shaft 20 is turned, the scraping blade 21 is stuck to the conductive surface of the inner tube 17 due to the pressure of the aqueous solution, and has a structure in which the attached fine ice is accurately scraped. The scraped crystal ice is mixed with brine, maintained in fluidity, sent to the regenerator 6 while being supercooled, separated vertically by the specific gravity difference between water and ice, and the ice is floated at the top and stored in ice. The water is sent to the brine cooler 4 again by the circulation pump 11 and becomes liquid ice. When the vacuum pump is stopped, that is, when cooling of the vegetables is stopped, the brine three-way valve 14a is switched to flow the cooling brine from the brine cooler 4 into the regenerator 6, and circulates exclusively to produce a mixed solution of ice and brine. Float, accumulate ice sequentially, and cool. For example, the Naiburain a 40% aqueous solution circulates cooling as brine, was adjusted to the refrigerant evaporation temperature -10 ° C., the Kori混Ri 60% containing water was frozen -5 ° C. ~-3
° C brine could be obtained. The resulting ice is fine and fluid and can be sent directly to a cold trap or cold storage tank by a pump to cool or store the ice. Due to the structure of the brine cooler 4, the water in the brine precipitates ice particles while being supercooled in the solution. Therefore, there is a concern that ice adheres to the cooling coil and lowers the cooling capacity as in the previously proposed regenerator. There is no.

Next, the cold storage tank 6 of the present invention is not provided with a cooling coil, but stores brine and stores fine ice. At the time of vacuum cooling of vegetables, brine cooled to about -5 ° C to -3 ° C from the brine cooler 4 is introduced into the cold trap, and heat exchanges with the evaporated water of vegetables to reach about 3 ° C. It flows into the cold storage tank 6. On the other hand, when the vegetables are not vacuum-cooled at night, the brine mixed with ice particles cooled to about -5 ° C to -3 ° C in the brine cooler 4 is switched to the regenerator 6 by switching the three-way brine valve 14a. be introduced. By this repetition, the brine in the regenerator has fine ice having a low specific gravity floated on the upper portion thereof, and the ice is not fused, but is a collection of ice particles. The ice particles accumulated in the upper part of the regenerator have a large surface area and melt quickly. The 3 ° C. brine coming from the cold trap thaws the ice
The latent heat of kcal / kg is deprived to 0 ° C. The 0 ° C. brine is sent to the brine cooler 4 by the brine circulating pump 11 and cooled again to −5 ° C. to −3 ° C. in the cooler 4. It is sent directly to the cold storage tank 6. Thus, the cold storage tank 6 of the present invention
In the prior art, there is no ice making refrigerant pipe provided by a cooling coil as in the prior application, and there is no circulation of the refrigerant to the regenerator 6, and the cooling from the temperature raising brine and the brine cooler 4 exclusively through the cold trap. It is a system to introduce brine. That is, during the night when vegetables are not cooled, brine mixed with ice is generated by the brine cooler 4 and the cold storage tank 6 is cooled.
During the vacuum cooling operation for storing ice and cooling vegetables, the latent heat of melting of the thin ice in the cold storage tank 6 is utilized, and the brine can be efficiently cooled by the brine cooler, and the above proposal is made. The equipment cost for the brine cooling coil 19 (see FIG. 3) in the regenerator 6 and the power consumption for the agitating pump provided to keep the cooling coil from icing in the vacuum storage device can be reduced. In addition, vegetables can be cooled efficiently at low cost.

The brine which can be used in the present invention requires -3 to -5 ° C brine to cool the surface of the cold trap to about 0 ° C. It is preferable to use them. For example, concentration 40
% Can be efficiently cooled. A 40% aqueous solution of Nybrine ( ie containing water 6)
0% ) has a freezing point of -12 ° C. and a specific gravity of 1.055 kg / 1.
And is most suitable for use as a brine in the apparatus of the present invention. The same can be said for an aqueous solution of ethylene glycol of 20% or more. Also, those having the same action as above can be used as brine. With this cold storage method, the capacity of the refrigerator becomes less than half that of the conventional case,
Along with this, the auxiliary equipment such as cooling towers and circulation pumps are also reduced, and a brine stirring pump for avoiding icing on the cooling coil provided in the cold storage tank is not required, and equipment costs are reduced, especially Contract electricity rates are reduced by about 30%,
The use of late-night electricity also reduced electricity bills by about 25%. FIG. 4 is an explanatory diagram relating to the heat storage operation. Assuming that the vegetable cooling operation load is P ₁ Kcal / H, P ₂ Kc is の of P ₁
If al / H is operated at night and stored as ice in a cold storage tank, P ₁ Kcal / H can be processed during a vacuum cooling operation with a 1/2 volume brine cooler, and cooling can be performed with energy saving. I understand.

[0014]

[Function] The refrigerator can be operated continuously by installing a cold storage tank for cooling cold traps in the vacuum cooling device. It is used for cold trap cooling when the vacuum device for cooling vegetables is used, and ice is exclusively generated when cooling vegetables is stopped. And circulate a fine iced brine. This iced brine
Has excellent fluidity and can be circulated through piping as it is.
You. In addition, the regenerator of the present invention has a simple structure in which a cold coil is not provided in the regenerator only by introducing warmed brine from a cold trap and ice-mixed brine from a brine cooler. , About -5 ° C to -3 ° C can be stored with energy saving, that is, the thin ice that floats can be stored sequentially, thereby utilizing not only sensible heat but also its latent heat of melting of about 80 kcal / kg. Has the effect of being able to

[0015]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. A specific example in the case of pre-cooling vegetables using the vacuum cooling device with a cool storage tank of the present invention will be described. In the device of the present invention, (1) the refrigerant (Freon R-22) is supplied from the compressor 3 to the condenser 5 to the expansion valve 1 both during the cooling operation of the vegetables and when the cooling is stopped.
5 → brine cooler 4 → compressor 3 to cool the brine, and the brine is cooled by the brine cooler to produce a cooling brine mixed with fine ice particles. (2) During operation, the brine is stored in the cold storage tank 6-(0 ° C) →
Circulating pump 11- (1 ° C) → brine cooler 4-(-
5 ℃ -3 ℃ ) → Cold trap 2- (3-8 ℃)
→ Cold storage tank 6 (1 ° C.) → Flow to brine cooler 4, and when work is stopped, flows from brine cooler 4 to cold storage tank 6 to store ice. (3) Specifications of Vacuum Cooling Device Table 1 shows an example of the device specifications (pre-cooling processing amount, cooling capacity, available latent heat, etc.) when pre-cooling vegetables using the vacuum cooling device having the cold storage tank of the present invention. Show.

The non-heat storage method uses a 160 hp (120 kW) rated brine, and the heat storage method uses a 60 hp (45 kW) rated brine cooler.

[0017]

[Table 1]

(4) Apparatus of the present invention and JP-A-61-8655
Table 2 shows the features of the No. 3 device.

[0019]

[Table 2]

As shown in Table 2, the total capacity of the refrigerating apparatus is 58% in the apparatus of Japanese Patent Application Laid-Open No. 61-86553 compared to the conventional apparatus, but in the present invention, due to the simplification of the apparatus of the regenerator, It can be reduced to 56%, and the use of a special brine cooler can prevent icing on cooling coils, etc., and can be scraped off by the scraping blades of the brine cooler.
Since, it is possible to more finely ice particles, flow
It has the characteristics and effects that it has excellent properties, is easy to circulate in a tube, and is easy to melt ice in a regenerator. (5) Facility costs and electricity costs The facility costs are somewhat higher for the thermal storage system, but the electricity costs are lower. In other words, the equipment cost of the regenerator must be added, but the capacity of the brine cooler and the auxiliary equipment is reduced by half, so that the increase in the equipment cost is not so large. on the other hand,
The basic electricity charge is about 60%, and the electricity charge is industrial heat storage adjustment contract (for high-voltage power, 6KV), and if nighttime electricity is used, it becomes cheaper. . Further, it can be directly used for a differential pressure pre-cooling device using brine as a cooling medium, a refrigerator for vegetables and fruits such as apples and the like.

[0021]

The present invention has the following effects and features. 1. A special brine is used to cool the cold trap for vacuum cooling, a cold storage tank is attached to the vacuum cooling device, the brine cooler is operated day and night, and a cycle exclusively for ice storage in the cold storage tank is used at night, and this cold storage is used during the day. The cold trap is cooled by the sum of the latent heat of melting of the ice in the tank and the cooling capacity of the brine cooler, and utilizes not only the sensible heat of the brine but also the latent heat of the ice. It uses energy. And late night electric power can be used for ice storage, which can save energy. 2. Brine cooling is a method in which brine in a cooling cylinder is swirled. When the pressure of a brine that has been supercooled by high speed decreases, 60% of the contained water freezes to generate ice fine particles. The cold brine mixed with ice particles at −5 ° C. to −3 ° C. is introduced into a cold trap when cooling vegetables, and is introduced into a cold storage tank when cooling vegetables at night is stopped, and ice is stored therein.
In the regenerator, a cooling coil and a stirring pump can be omitted, and the equipment can be simplified. 3. The capacity of brine cooler and accessories is 1 /
As a result of 2, the entire facility becomes smaller and the building becomes smaller. 4. Even if the brine cooler breaks down, it can be operated with the ice-mixed brine in the cold storage tank.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a vacuum cooling device with a regenerator according to the present invention.

FIG. 2 is a schematic view of a conventional vacuum cooling device.

FIG. 3 is a schematic view of a vacuum cooling device described in JP-A-61-86553.

FIG. 4 is an explanatory diagram relating to an operation load related to animal heat operation.

FIG. 5 is a schematic sectional view of the brine cooler 4 of the present invention.

FIG. 6 is a schematic view showing a state where a scraping blade is attached.

[Explanation of symbols]

In the figure, 1 is a vacuum tank, 2 is a cold trap, 3 is a compressor, 4 is a brine cooler, 5 is a condenser, 6 is a cold storage tank, 1
0 is a refrigerant pipe, 14a is a brine switching three-way valve, 15 is an expansion valve, 16 is a jacket, 17 is a brine cooler cylinder, 18 is a dasher blade, 19 is a regenerator cooling coil, 20 is a scraper blade mounting shaft, and 21 is a scraper. Blades, 22 a geared motor, 23 a brine inlet, 2
4 is a brine outlet, 25 is a refrigerant inlet, 26 is a refrigerant outlet, 27 is a heat insulating material, and 28 is a heat exchanger cover.

Claims (1)

(57) [Claims] 1. A vacuum pump 8 for evacuating a vacuum tank 1 for vacuum cooling vegetables, a cold trap 2 for condensing water vapor evaporating from vegetables, and a brine cooler 4 for cooling brine circulating through the cold trap. In a vegetable vacuum cooling apparatus comprising a compressor 3 and a condenser 5 for a refrigerant circulating in a brine cooler and a regenerator 6 provided between the brine cooler 4 and the cold trap 2, The cooler 4 is a cylindrical body of a double pipe of an inner pipe 17 through which brine flows and an outer pipe 16 through which a refrigerant having a refrigerant evaporation temperature of -10 ° C. flows, and crystal ice adhered and deposited on the inner surface of the inner pipe 17 therein. A scraping blade 21 for scraping off water, circulates the brine aqueous solution at high speed in the inner pipe 17 of the brine cooler 4 and supercools it to precipitate three-dimensional ice particles in the solution; The ice particles adhering and depositing on the inner surface of the inner pipe 17 are scraped off to produce a sherbet in which brine and ice are mixed, and the warmed brine from the cold trap 2 and the brine cooler 4 are switched by switching the three-way valve 14a. The cooling brine from the condenser 5 flows through the expansion valve 15 to the brine cooler 4 when the vegetables are vacuum-cooled, and the brine in the cool storage tank 6 is Circulation pump 11
Into the brine cooler 4 to be cooled to -5 ° C. to -3 ° C. to form a sherbet brine mixed with ice particles in which 60% of the water content is frozen, and then the cold trap 2
And heat exchange with vegetable water vapor to condense the water vapor, which is warmed and flows to the cold storage tank 6, where it is piped to about 0 ° C. due to the latent heat of melting of the stored ice in the cold storage tank. Then, the brine three-way valve 14a is switched to introduce a sherbet brine containing ice particles in which 60% of the water content is frozen from the brine cooler 4 into the regenerator 6, and the fine ice is sequentially accumulated and cooled as described above. A vegetable vacuum cooling device with a cold storage tank, which is provided with piping.