JPH04106380A - Ice making device - Google Patents

Abstract

PURPOSE:To prevent the adhesion of ice to a heat transfer tube by a method wherein the spray nozzles of ice making water are provided in the upper part of the heat transfer tube while the spray nozzles of the ice making water are provided in the lower part of the heat transfer tube in accordance with necessity. CONSTITUTION:The upper end side of a heat transfer tube 1 is constituted of a sealed structure and the spray nozzles 4 of ice making water 3 are provided in the upper part of the heat transfer tube 1, further, the multi-stage spray nozzles 5 of the ice making water 3 are provided in the lower part of the heat transfer tube 1 in accordance with necessity whereby the preventing effect of the adhesion of ice can be enhanced much more. High-pressure spray nozzles 5, capable of securing a given colliding energy against the wall surface of the tube 1, are used since the washing of the wall surface of the tube 1 and the separation of the adhered ice to the same are required while the intermittent spraying of the ice making water 3 is effected at a time point when the heat transfer amount of a heat exchanger is deteriorated.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an ice making device for an ice heat storage device used for air conditioning and cooling of buildings, food storage, and the like.

(Conventional technology) An ice heat storage device uses cheap late-night electricity to operate a refrigerator to store ice and then melts the ice during the day when electricity costs are high to utilize the cold energy, which utilizes the latent heat of solidification of water. Because of its heat storage method, compared to the conventional ice heat storage device that uses the sensible heat of water,
Since heat storage tanks can be significantly downsized, they have recently become popular.

Conventionally, this type of ice-making equipment for ice heat storage has been designed to flow low-temperature refrigerant or antifreeze to the -blade side of the ice-making heat exchanger tube (heat exchanger), and flow water to the other side to directly contact the surface of the heat exchanger tube. The fixed ice-making method is widely adopted because the equipment cost is low, but this method requires large equipment because the thermal resistance of the heat transfer surface increases as the ice layer grows, reducing the ice-making capacity. Moreover, due to the fixed ice, the thermal response during ice melting is poor, making it impossible to respond to sudden changes in heat load.

In response to this, a method for producing fluid ice has recently been proposed. For example, as shown in Figure 5, on page 77 of the November 17, 1986 issue of Nikkei Mechanical, there is A falling water film method uses a fluorocarbon liquid refrigerant on the outside of the heat transfer tube of a tube heat exchanger, and water overflows and falls onto the vertical surface inside the heat transfer tube to produce very thin sherbet-like (fluid) ice. It has been proposed and is publicly known that, unlike the conventional fixed ice making method, there is no deterioration in ice making capacity over time because it makes fluid ice, and the heat storage tank is filled with water to store heat in this fluid ice. It has the advantages of high efficiency, good thermal response during ice thawing, and low ice making cost.

(Problem to be Solved by the Invention) However, since this ice-making device uses a shell-and-tube system consisting of a heat exchanger or a large number of small-diameter heat exchanger tubes, the upper end of each heat exchanger tube is at the same level. This results in uneven water overflow and fall.
Since cooling (heat transfer) is uneven and ice builds up on the heat exchanger tubes, there was a problem that the ice making was in a fluid state and it was easy to stop, making continuous operation difficult.

An object of the present invention is to provide a compact and inexpensive ice-making device by preventing the above-mentioned problem of icing on heat transfer tubes.

(Means for Solving the Problems) The present invention has the following configuration in order to achieve the above object. That is, (1) flowing the cooling liquid to the outside of the heat exchanger tube of the vertical heat exchanger,
In an ice making device that produces fluid ice by forming a film of falling water on the inside of a tube, an ice making water spray nozzle is provided in a heat transfer tube.

Furthermore, if necessary, (2) an ice-making water injection nozzle is provided in the heat exchanger tube.

(Function) Since the present invention is configured as described above, a uniform water film is formed inside the heat transfer tube by the uniform dispersion effect of the spray nozzle, and an air barrier is formed between the ice crystals by the bubble accompanying action of the spray water. By forming this, ice formation on the heat transfer tubes can be suppressed and fluid ice can be made continuously.

Furthermore, since the heat transfer tubes are intermittently cleaned with high-speed ice-making water from the injection nozzle, there is no adhesion of ice or dirt to the inner wall surfaces of the tubes.

(Examples) Hereinafter, the present invention will be specifically described according to examples shown in the drawings.

FIG. 1 is a block diagram of an ice making apparatus showing an embodiment of the present invention, and FIGS. 2 and 3 are views A-A and B-8 of FIG.
FIG.

The heat transfer tubes 1 of the vertical double tube heat exchanger are required to have functions such as high thermal conductivity, airtightness, and corrosion resistance, and therefore metal tubes such as stainless steel or aluminum are usually used.

On the other hand, the outer shell tube 2 of the heat exchanger, which is provided to cover the outer periphery of the heat exchanger tube 1, is usually made of the same material as the heat exchanger tube 1 because it is required to have functions such as heat insulation, airtightness, and corrosion resistance. Use a heat insulating material on its outer surface.

The upper end of the heat exchanger tube 1 has a sealed structure, and a spray nozzle 4 for ice-making water 3 is provided above the heat exchanger tube 1, and further, if necessary, spray nozzles 5 for ice-making water 3 are provided in multiple stages within the heat exchanger tube 1. This makes it possible to further improve the icing prevention effect.

The spray nozzle 4 is usually a low-pressure spray nozzle with a water droplet diameter of 1000 mm or less to reduce entrainment of air bubbles to prevent icing on the heat transfer tubes and energy loss due to pump pressure increase.

Since the injection nozzle 5 needs to clean the wall surface of the tube 1 and remove the adhering water, a high-pressure injection nozzle that can secure a certain amount of collision energy on the wall surface of the tube 1 is used, and when the amount of heat transfer in the heat exchanger decreases, the ice-making water is removed. It is better to perform intermittent injection as shown in step 3, or to perform intermittent injection periodically at fixed intervals in order to more reliably prevent pipe wall icing.

Note that when the tube diameter of the heat exchanger tube 1 is large, a plurality of injection nozzles 5 are provided close to the tube wall surface of the heat exchanger tube 1 in the circumferential direction.

The lower end side of the heat exchanger tube 1 has an open structure, and a heat storage tank 6 is provided at the bottom of this.
will be established. Since this heat storage tank 6 is required to have functions such as non-leakage, heat insulation, and corrosion resistance, it is usually made of FRP or the like with a heat insulating material applied to its outer surface.

Coolant 7 completed between heat exchanger tube 1 and outer shell tube 2 of heat exchanger
Normally, antifreeze is used and heat is exchanged with the refrigerant in the refrigeration circuit (not shown in the diagram) using an indirect heat exchanger to cool it to below 0°C and circulated, but it is not possible to use the refrigerant in the refrigeration circuit directly. Of course, it is also possible.

Furthermore, although this embodiment is a case in which the heat exchange between the ice-making water 3 and the cooling liquid 7 is in countercurrent flow, it is of course also possible to supply the cooling liquid 7 from the upper side of the heat exchanger to perform heat exchange in parallel flow. It is.

The lower part of the heat storage tank 6 and the spray nozzle 4 are connected by a water pipe 8a,
A pump 9a is provided in this pipe 8a to continuously supply ice-making water 3 to the spray nozzle 4.

The ice-making water 3 supplied from the spray nozzle 4 forms a uniform water film 10 above the heat transfer tube 1, and is cooled by the cooling liquid 7 to produce fluid ice 11.

In addition, the lower part of the heat storage tank 6 and the injection nozzle 5 are connected by a water pipe 8b, and a pump 9b is installed in this pipe 8b to intermittently inject high-speed ice-making water 3 into the heat transfer tube 1 to clean the inner wall surface of the pipe. Prevent icing.

Arrows in the figure indicate the flow directions of the ice-making water 3 and the cooling liquid 7.

Next, the operational functions of the present invention will be explained.

First, a cooling liquid 7 at a temperature of 0° C. or lower is passed between the heat transfer tubes 1 and the outer shell tubes 2 of the double-tube heat exchanger, and the produced water 3 is cooled by convective heat transfer of the cooling liquid 7.

On the other hand, the ice-making water 3 fed from the lower part of the heat storage tank 6 by the pump 9a is evenly sprayed on the inner wall surface of the heat exchanger tube 1 by the spray nozzle 4, forming a uniform water film 10 inside the heat exchanger tube 1.

This falling water film 10 is indirectly cooled by the cooling liquid 7 while flowing down the heat transfer tube 1, and becomes supercooled water.The turbulence of the falling water film 10 destroys this supercooled state, and the supercooled water becomes visible. Fluid ice 11 corresponding to heat is produced.

In this fluid water 11, air diaphragms are formed between the frozen products due to the bubble-associated action of the sprayed water, so that fine fluid ice with a water diameter of about 200 mm or less is usually formed.

The ice-making water 3 accompanied by the fluid ice 11 that has flowed down to the lower end of the heat transfer tube] naturally falls into the heat storage tank 6, and uses the difference in specific gravity between the ice-making water 3 and the fluid ice 11 to Ice heat storage is performed on the top of the

If necessary, (1) add an ice-making lubricant such as ethylene glycol (abbreviated as EC) to the ice-making water 3 to adjust the water quality and freezing (solidification) temperature.

■In order to prevent ice from forming on the inner wall surface of the heat exchanger tube 1 of the heat exchanger, the inner surface of the heat exchanger tube 1 is coated with a thin film of non-adhesive and water-repellent fluororesin.

etc. are of course possible.

In addition, if the amount of ice-making water 3 from the spray nozzle 4 is small,
In this case, the cooling of the collision part of the spray water is too strong and ice builds up on the tube wall surface near the collision part.
The ice-making apparatus shown in FIG. 4 has a non-cooling structure on the upper side.

Further, in this embodiment, the heat exchanger structure of the ice making apparatus is a double-tube type, which is the simplest structure, but it is of course possible to use a shell-and-tube type heat exchanger with a multi-tube structure.

In order to confirm the effects of the ice making apparatus of the present invention, an ice making comparison test between the present invention and the prior art was conducted under the equipment conditions and ice making conditions shown in Table 1.

As a result, as can be seen from the test results in Table 1, the spray ice film method of the present invention has a continuous ice making time (experimentally confirmed up to 3 hours) of about 7 times or more compared to the conventional overflow water film method. It was confirmed that the amount of ice produced was approximately 8 times or more, and the productivity of producing fluid ice was excellent.

In addition, in terms of water quality, the water quality is fine, spherical and flowing water with a diameter of 200 mm or less, compared to the thin scaly shape of the conventional overflow water film method, which has excellent thermal response during ice melting (using cold energy). ing.

Furthermore, even with regard to water adhering to the pipe wall due to sudden changes in ice-making conditions, the water quality is soft and consists of spherical aggregates, so the adhering water can be easily peeled off by spraying ice-making water at high speed onto the pipe wall. .

(Effects of the Invention) As explained above, since the ice making device of the present invention is provided with the ice making water spray nozzle in the heat exchanger tube of the vertical heat exchanger, and also has the configuration in which the ice making water spray nozzle is provided, There are the following notable effects.

■ By providing a spray nozzle, a uniform water film is formed inside the heat transfer tube due to the even dispersion effect of the spray nozzle, and an air barrier is formed between ice crystals due to the bubble-accompanied action of the spray nozzle. The fluidity is good, there is no ice buildup on the pipe wall surface, and the equipment can be made compact.

■Furthermore, since the heat transfer tubes are cleaned using the injection nozzle, it is possible to prevent ice from forming on the tube wall surface in the event of trouble and to prevent deterioration of cooling performance due to adhesion of dust, etc., making it possible to produce ice in a stable fluid state.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of an ice making apparatus showing an embodiment of the present invention, and FIGS. 2 and 3 are planes A-A and B-B of FIG.
FIG. Moreover, FIG. 4 is a block diagram showing another embodiment of the present invention, and FIG. 5 is a conceptual diagram showing a conventional technique. 1...Heat transfer tube 2...Outer shell tube 3...
Ice-making water 4... Spray nozzle 5... Spray nozzle 6... Heat storage tank 7... Cooling liquid
8...Water piping 9...Pump 1
0...Water Membrane 11...Fluid ice diagram Rum

Claims (2)

[Claims] (1) Pour the cooling liquid on the outside of the heat transfer tube of the vertical heat exchanger,
An ice making device for producing fluid ice by forming a film of falling ice making water on the inside of a tube, characterized in that an ice making water spray nozzle is provided in a heat transfer tube. (2) The ice making apparatus according to claim 1, further comprising an ice making water injection nozzle provided within the heat transfer tube.