WO2023282390A1 - Ice maker utilizing cooling coil having dual pipe structure - Google Patents

Abstract

Disclosed is an ice maker utilizing a cooling coil having a dual pipe structure. The ice maker according to the present invention utilizes a cooling device having an improved structure in which a cooling coil having a dual pipe structure for a refrigerant of a main body compressor and a refrigerant of a refrigerant cooling compressor is buried in an insulating oil storage tank. The ice maker is equipped with a cooling system that replaces cooling water, and thus can reduce water bills while having an ice-making capability on par with existing water-cooling ice makers. In addition, there is no risk of the ice maker freezing in winter.

Description

Ice maker with double tube structure cooling coil

The present invention relates to an ice maker, and more particularly, to provide a cooling system that replaces cooling water so as to reduce water bills by about 700,000 won per month while having an ice making capacity corresponding to that of existing water-cooled ice makers. It is about an ice maker applied.

In general, an ice maker performs an ice-making process by supplying water into an ice-making chamber to perform ice-making, and an ice-making process in which hot gas is supplied after ice is made to transfer the ice to an ice storage chamber as one cycle, and the ice-making process is repeated. ice with

The performance of these ice makers may vary depending on the efficiency of dissipating heat from the condenser to the outside, and is divided into an air-cooled ice maker in which heat from the condenser is cooled by external air and a water-cooled ice maker in which water is used to cool the condenser. Since air-cooled ice makers have a low ice-making performance including ice-making amount and a high failure rate when the outside temperature increases in summer, recently an ice-maker equipped with a water-cooled condenser that improves ice-making performance by cooling the condenser using water has been proposed. Water-cooled condensers are not only more expensive than air-cooled condensers, but also consume a lot of water by continuously supplying cooling water to cool the refrigerant, which not only burdens water bills but also has a problem of freezing and bursting in cold winter.

A conventional ice maker for solving this problem is disclosed in Korean Patent Registration No. 10-1256415. According to the registered patent, a water reservoir in which ice-making water or ice-separating water falls and is stored, an ice-making frame in which ice is formed by spraying and supplying the ice-making water to a lower surface and separated by supplying the ice by spraying and supplying the ice-separating water to an upper surface, and the ice-making frame An ice maker including an evaporator in which a refrigerant circulates to grow the ice-making water injected and supplied to the lower surface of the evaporator and a condenser to cool the refrigerant circulating in the evaporator, wherein the water discharged beyond the storage level of the water reservoir and a cooling device for pre-cooling the refrigerant before flowing into the condenser by exchanging heat with the refrigerant before flowing into the condenser, thereby selecting the refrigerant before flowing into the condenser using low-temperature water discarded as wastewater. By cooling, the condenser's operation time can be reduced, which improves the energy efficiency of the ice maker.

However, it is easy to apply the conventional ice maker as described above to a refrigerator, but it is practically difficult to apply the ice maker because the amount of ice is lower than that of the water-cooled type to be applied to an actual ice maker. Since cooling water must be discharged, there is a problem in that water consumption is reduced to some extent but not significantly. In addition, there is a problem that the risk of freezing and bursting still exists because water is used.

The present invention was developed to solve the above problems, and the technical problem to be achieved by the present invention is to have a cooling system that replaces the cooling water, so that it has an ice-making capacity corresponding to that of existing water-cooled ice makers, and can produce water of about 700,000 won per month. It is to provide an ice maker to which a cooling device having an improved structure in which a cooling coil having a double tube structure for a main body compressor refrigerant and a compressor refrigerant for cooling the refrigerant and the cooling coil is buried in an insulating oil storage tank is applied so as to enable cost reduction.

The main body 20, the insulating oil 22, which is oil used for electrical insulation inside the transformer by filling the inside of the main body 20, and the first refrigerant for cooling the refrigerant from the small compressor 102 for cooling the refrigerant (L_COOL) Insulation oil 22 A double tube structure cooling unit 120 installed to be immersed in; The temperature is lowered by the double pipe structure cooling unit 120, and the second refrigerant (L_HOT) discharged from the inner pipe 26 removes moisture and foreign substances and expands the first dryer 122 and the second refrigerant (L_HOT). It includes an expansion valve 124 for rapidly cooling the temperature, a cold plate 126 for making ice, and a vaporizer 128, and the temperature is raised by the double pipe structure cooling unit 120, and is discharged from the external pipe 24 A second dryer 132 for removing moisture and foreign substances contained in the first refrigerant (L_COOL) for cooling the refrigerant compressed by the compact compressor 102 for cooling the refrigerant, and moisture and foreign substances by the second dryer 132 It is characterized in that it comprises a capillary tube 134 for cooling the removed refrigerant for cooling.

In addition, the insulating oil 22 is preferably a mixture of 10 to 30 parts by weight of PAO base oil-based engine oil based on 100 parts by weight of the insulating oil.

The ice maker according to the present invention is equipped with a cooling system that replaces the cooling water by applying a cooling coil having a double tube structure for the main body compressor refrigerant and the compressor refrigerant for cooling the refrigerant and an improved cooling device in which the cooling coil is embedded in an insulating oil storage tank, It has an ice-making capacity equivalent to that of existing water-cooled ice makers, while reducing water bills. Also, there is no risk of freezing in winter.

1 is a block diagram schematically showing the structure of an ice maker to which a cooling coil having a double pipe structure according to a preferred embodiment of the present invention is applied; and

FIG. 2 is a cross-sectional view showing the structure of a dual tube structure cooling unit 120, which is a key component of the present invention, provided in the ice maker of FIG. 1;

Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the accompanying drawings.

1 schematically shows the structure of an ice maker to which a cooling coil having a double pipe structure according to a preferred embodiment of the present invention is applied. Referring to FIG. 1 , an ice maker according to the present invention is an ice maker that manufactures ice, and includes an ice making compressor 100 and a small compressor 102 for cooling refrigerant installed separately from the ice making compressor 100 .

In addition, the ice maker has a main body 20 with an open interior and a sealed top, an insulating oil 22 filled in the main body 20, which is oil used for electrical insulation inside the transformer, and a small compressor for cooling the refrigerant ( An outer pipe 24 through which the first refrigerant (L_COOL) for cooling the refrigerant from 102 passes, and an inner pipe 24 embedded in the outer pipe 24 and through which the second refrigerant L_HOT from the ice-making compressor 100 passes It has a double tube structure cooling unit 120 installed so that the pipe 26 is immersed in the insulating oil 22 while forming a coil shape.

In addition, the ice maker has a temperature lowered by the double tube structure cooling unit 120, and the first dryer 122 and the second refrigerant remove moisture and foreign substances from the second refrigerant (L_HOT) discharged from the inner pipe 26. It includes an expansion valve 124 for rapidly cooling the temperature by expanding (L_HOT), a cold plate 126 for making ice, and a vaporizer 128,

The temperature is increased by the double pipe structure cooling unit 120, and the moisture and foreign substances contained in the first refrigerant (L_COOL) for refrigerant cooling discharged from the external pipe 24 and compressed by the small compressor 102 for cooling the refrigerant are removed. A second dryer 132 to remove;

It includes a capillary tube 134 for cooling the refrigerant for cooling from which moisture and foreign substances are removed by the second dryer 132 .

FIG. 2 shows the structure of the dual tube structure cooling unit 120, which is a key component of the present invention, provided in the ice maker of FIG. 1 as a cross-sectional view. Referring to FIG. 2, the double pipe structure cooling unit 120 includes a main body 20 with an open interior and a sealed top, and an insulating oil 22, which is oil used for electrical insulation inside the transformer to be filled inside the main body 20. And, an external pipe 24 through which the first refrigerant cooling L_COOL from the small compressor 102 for cooling the refrigerant passes, and a second pipe 24 embedded in the external pipe 24 and supplied from the compressor 100 for ice making. The inner pipe 26 through which the refrigerant L_HOT passes is installed so as to be immersed in the insulating oil 22 while forming a coil shape. As such, it is noteworthy that the double pipe structure cooling unit 120 has a structure in which the outer pipe 24 and the inner pipe 26 are formed in a coil shape and are immersed in the insulating oil 22 .

Since the insulating oil has excellent electrical conductivity, the temperature of the second refrigerant (L_HOT) passing through the inner pipe 26 is cooled by the first refrigerant (L_COOL) passing through the outer pipe 24 and the outer pipe 24 is in contact with the insulating oil. Therefore, the first refrigerant (L_COOL) is cooled. In particular, if the refrigerant cooling compressor 102 is intensively operated in the ice-breaking operation section where the cold plate 126 is not operated due to the nature of the ice maker, the first refrigerant (L_COOL) can be quickly cooled, making it an actual ice maker even in hot summer. 2 The temperature of the refrigerant (L_HOT) can be maintained at a sufficient level. In addition, since the freezing point of insulating oil is significantly lower than that of water, there is no fear of freezing or bursting even if it is left for a long time in winter.

The performance of the ice maker as described above was compared and evaluated with the water-cooled ice maker and the air-cooled ice maker. Table 1 below shows the results of comparative evaluation of the daily ice making amount of the ice maker according to the present invention and the air-cooled ice maker when the ice making amount per day of the water-cooled ice maker is 100 and the indoor temperature during ice making is in the range of 15 ° C to 35 ° C.

division	amount of ice (Indoor 15℃)	amount of ice (Indoor 20℃)	amount of ice (Indoor 25℃)	amount of ice (Indoor 30℃)	amount of ice (Indoor 35℃)	note
the present invention	95	97	94	95	97
water cooled ice maker	100	100	100	100	100	when the temperature rises water usage upsurge
air cooled ice maker	74	71	62	45	30	When the temperature rises Ice making volume drastically decreased

Referring to Table 1, the ice maker according to the present invention not only showed a similar level of ice-making ability to the water-cooled ice maker in the entire range of the room temperature from 15 ° C to 35 ° C, but also did not use cooling water, so the amount of water used in all temperature conditions was the same as that of the air-cooled ice maker. is only However, in the case of a water-cooled ice maker, the amount of water used for cooling increases rapidly as the indoor temperature during operation increases, and the ice-making capacity of the air-cooled ice maker rapidly decreases as the indoor temperature increases.

Therefore, the ice maker according to the present invention has a cooling system that replaces the cooling water by applying a cooling coil having a double tube structure for the main body compressor refrigerant and the compressor refrigerant for cooling the refrigerant and an improved cooling device in which the cooling coil is embedded in an insulating oil storage tank. By installing it, it is possible to reduce water bills while maintaining the ice-making capacity equivalent to that of existing water-cooled ice makers.

However, the ice maker according to the preferred embodiment of the present invention as described above is caused by a temperature difference between the temperature of the second refrigerant (L_HOT) passing through the inner pipe 26 and the temperature of the first refrigerant (L_COOL) passing through the outer pipe 24. In the case of long-term use of insulating oil, a decrease in thermal conductivity may occur due to a change in the acid value of the insulating oil.

In order to prevent this, according to the present invention, PAO base oil-based engine oil is additionally mixed with the insulating oil 22.

Regarding the type of engine oil base oil, according to the classification criteria of the American Petroleum Institute (API), the type of engine oil base oil can be classified into a total of 5 stages from group 1 to group 5. Among them, group 1 and group 2 are commonly called mineral oil, and engine oils using base oils from group 3 to 5 are called synthetic oil.

Mineral oil (Grade 1-2) is a base oil that belongs to Groups 1 and 2 of the API classification standard, and oil that comes out between bunker C oil and asphalt is used in the crude oil refining process. Since it is oil extracted right above the asphalt, which can be called crude oil residue, it can be said that it is low-grade oil even if it is not luxurious in origin. Mineral oil-based oil has many impurities and incomplete molecular structures, so the molecular structure is easily broken in high-temperature and high-pressure environments such as in engines. Therefore, engine oil based on mineral oil has many difficulties in maintaining viscosity and has a short lifespan.

VHIV (grade 3) base oil belongs to the 3rd group according to the API classification standard and is VHIV. Engine oils that use VHIV as base oil are often referred to as synthetic oils, but in fact, there has been a lot of controversy over whether engine oils made with VHIV base oils can be called synthetic oils. VHIV base oil is the most widely used base oil in recent years because it is relatively inexpensive and shows performance comparable to PAO, which will be discussed later, due to the development of technology.

PAO base oil belonging to group 4 according to the API classification standard has a higher viscosity index than VHIV, but has excellent low-temperature fluidity and high oxidation resistance. According to another embodiment of the present invention, 10 to 30 parts by weight of engine oil based on PAO base oil is added to 100 parts by weight of insulating oil. Other base oils were found to be unsuitable as a result of basic tests in terms of thermal stability and temperature retention.

[Example 1]

100 parts by weight of insulating oil, 15 parts by weight of engine oil based on PAO base oil

[Example 2]

100 parts by weight of insulating oil, 20 parts by weight of engine oil based on PAO base oil

[Example 3]

100 parts by weight of insulating oil, 25 parts by weight of engine oil based on PAO base oil

[Comparative Example 1]

100 parts by weight of insulating oil, no PAO base oil-based engine oil input

[Comparative Example 2]

100 parts by weight of insulating oil, 50 parts by weight of engine oil based on PAO base oil

The ice-making ability using the prepared insulating oil and the acid value of the insulating oil under harsh conditions (temperature 70 ° C, relative humidity 90%, 720 hours elapsed) were compared and evaluated. Acid value is expressed as mg of potassium hydroxide (KOH) required to neutralize the acid value component contained in 1g of insulating oil. In the case of new oil, it is less than 0.02 (KS C 2301 standard) and if the acid value exceeds 0.4 mg KOH/g, it is unsuitable. Do. The evaluation results are shown in Table 2.

division	Changes in acid value under harsh conditions (mg KOH/g)	note
Example 1	0.22	based on PAO base oil 15 parts by weight of engine oil
Example 2	0.27	based on PAO base oil 20 parts by weight of engine oil
Example 3	0.15	based on PAO base oil 25 parts by weight of engine oil
Comparative Example 1	0.6	based on PAO base oil No engine oil input
Comparative Example 2	0.1	based on PAO base oil 50 parts by weight of engine oil

Referring to Table 1, in the case of Comparative Example 1 in which PAO base oil-based engine oil was not introduced into the insulating oil, it was found that the acid value exceeded 0.6. On the other hand, in the case of Example 1 in which 15 parts by weight of PAO base oil-based engine oil was added to 100 parts by weight of insulating oil, the acid value was maintained within the allowable range at 0.22, and PAO base oil-based engine oil was added to 100 parts by weight of insulating oil. In the case of Example 2 where 20 parts by weight was added, it was 0.27, and in the case of Example 3 where 25 parts by weight of engine oil based on PAO was added to 100 parts by weight of insulating oil, it was 0.15, all of which were kept within the allowable range.

That is, when less than 10 parts by weight of PAO base oil-based engine oil is mixed with respect to 100 parts by weight of insulating oil, oxidation occurs due to high temperature, increasing the acid value of the insulating oil and reducing the cooling efficiency of the double pipe structure cooling unit 120. As a result, the ice-making performance deteriorates.

However, when PAO base oil-based engine oil is mixed in excess of 30 parts by weight with respect to 100 parts by weight of insulating oil, oxidation due to high temperature does not occur, but the viscosity is increased, resulting in a decrease in the cooling efficiency of the double pipe structure cooling unit 120 As a result, the ice-making performance was found to be degraded.

Therefore, it was found that it is most desirable to add 10 to 30 parts by weight of PAO base oil-based engine oil with respect to 100 parts by weight of insulating oil, considering the range in which the acid value does not increase and the viscosity does not increase due to high-temperature operation.

Claims (2)

1. In the ice maker for producing ice,

   Compressor 100 for ice making;

   A small compressor 102 for cooling refrigerant installed separately from the compressor 100 for ice making;

   The body 20 with the inside open and the top sealed, the insulating oil 22 that is filled inside the body 20 and used for electrical insulation inside the transformer, and the refrigerant from the small compressor 102 for cooling the refrigerant An outer pipe 24 through which the first refrigerant L_COOL for cooling passes, and an inner pipe 26 embedded in the outer pipe 24 and through which the second refrigerant L_HOT from the ice-making compressor 100 passes A double tube structure cooling unit 120 installed to be immersed in the insulating oil 22 while forming a coil shape;

   The temperature is lowered by the double tube structure cooling unit 120, and the second refrigerant (L_HOT) discharged from the inner pipe 26 removes moisture and foreign substances and expands the first dryer 122 and the second refrigerant (L_HOT). It includes an expansion valve 124 for rapidly cooling the temperature, a cold plate 126 for making ice, and a vaporizer 128,

   The temperature is increased by the double pipe structure cooling unit 120, and the moisture and foreign substances contained in the first refrigerant (L_COOL) for refrigerant cooling discharged from the external pipe 24 and compressed by the small compressor 102 for cooling the refrigerant are removed. An ice maker using a cooling coil having a double tube structure, characterized in that it comprises a second dryer 132 for removing water and a capillary tube 134 for cooling the refrigerant for cooling from which moisture and foreign substances are removed by the second dryer 132. .
2. The method of claim 1, wherein the insulating oil 22,

   An ice maker using a cooling coil having a double tube structure, characterized in that 10 to 30 parts by weight of engine oil based on PAO base oil is additionally mixed with 100 parts by weight of insulating oil.

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