A plate heat exchanger used in conjunction with a marine large temperature difference cold seawater unit

Abstract

The present invention relates to a plate heat exchanger used in conjunction with a marine large temperature difference cold seawater unit, and in particular to the technical field of refrigeration equipment. The plate heat exchanger includes a seawater waterway system consisting of a warm water inlet T1 and a cold water outlet T2, a refrigerant system consisting of a refrigerant inlet S1 and a refrigerant outlet S2, and the refrigerant in the plate heat exchanger is set to a double-flow flow type, including a full liquid supply layer and a dry liquid supply layer, respectively, the full liquid supply layer accounts for 2 / 3 of the entire refrigerant double-flow flow type, and the dry liquid supply layer accounts for 1 / 3 of the entire refrigerant double-flow flow type. The plate heat exchanger provided by the present invention has the characteristics of high heat exchange efficiency, small heat loss, compact structure, small footprint, easy installation and cleaning, wide application, long service life, etc. Under the same pressure loss, its heat transfer coefficient is 2-3 times higher than that of a shell and tube heat exchanger, and the footprint is more than half of that of a tube heat exchanger, and the heat recovery rate can be as high as more than 90%.

Description

Technical Field

[0001] The invention relates to the technical field of refrigeration equipment, and in particular to a plate heat exchanger used in conjunction with a marine large temperature difference cold seawater unit. Background Art

[0002] When fishing boats go out to sea for fishing operations, the catch has high requirements for ice flakes and cold water used for preservation. Ordinary chillers can no longer adapt to the special and harsh working conditions at sea. The domestic market for large temperature difference cold seawater units for ships has always been blank. In addition, traditional plate heat exchangers can only be supplied in dry or full liquid mode. Although the full liquid supply has high heat exchange efficiency, it is easy to frost and cause incomplete evaporation of refrigerant in the plate heat exchanger. A large amount of refrigerant liquid returns to the compressor, which harms the compressor and causes liquid hammer. In addition, the rapid drop in return air temperature will also cause oil rush in the compressor.

[0003] In modern technology, a traditional plate heat exchanger plus a gas-liquid separator is used in combination to solve this problem. The gas-liquid separator is used to prevent the refrigerant liquid that has not been completely evaporated and not overheated in the evaporator from entering the compressor, causing the compressor to frost and liquid hammer in wet compression. The gas-liquid separator is mainly composed of a shell, a U-shaped riser, a head, etc. In order to ensure good oil return, the flow rate requirements of the U-shaped riser of the gas-liquid separator need to be strictly controlled. It is generally recommended that the gas-liquid separator can accommodate 50% to 70% of the refrigerant in the system, so the volume of the gas-liquid separator is large, which increases the economic cost. The gas-liquid separator is to separate the refrigerant liquid that has not been completely evaporated and the refrigerant wet gas that has not been overheated in the evaporator from gas to liquid, allowing the refrigerant gas to enter the compressor, and the liquid remains in the cylinder and evaporates into gas before entering the compressor. In this process, although the damage to the compressor caused by frost is effectively avoided, the evaporation of the refrigerant does not play an effective heat exchange role and does not cool the water temperature. To this end, this patent proposes a plate heat exchanger for use with a marine large temperature difference cold seawater unit, which can solve the above-mentioned problems. Summary of the invention

[0004] (1) Technical issues to be resolved

[0005] The present invention aims at the above-mentioned problems in the prior art and to make up for the deficiencies of the prior art. The present invention provides a plate heat exchanger which can be reasonably manufactured and used in conjunction with a marine large temperature difference cold seawater unit.

[0006] (2) Technical solution

[0007] In order to solve the above technical problems, the present invention provides a plate heat exchanger for use in conjunction with a marine large temperature difference cold seawater unit, the plate heat exchanger comprising a seawater waterway system consisting of a warm water inlet T1 and a cold water outlet T2, a refrigerant system consisting of a refrigerant inlet S1 and a refrigerant outlet S2, the seawater waterway system and the refrigerant system together constitute a heat exchange system, the refrigerant in the plate heat exchanger is set to a two-way flow type, including a full liquid supply layer and a dry liquid supply layer, the full liquid supply layer accounts for 2 / 3 of the entire refrigerant two-way flow type, the dry liquid supply layer accounts for 1 / 3 of the entire refrigerant two-way flow type, the refrigerant system is provided with a throttling device, and the seawater waterway system is provided with a water flow thermostat.

[0008] Preferably, the seawater waterway system converts the 40°C seawater sent into the front warm water inlet T1 into 0-2°C cold water that flows out after cooling at the terminal cold water outlet T2, the refrigerant inlet S1 is connected to the condenser refrigerant outlet, and the refrigerant outlet S2 is connected to the compressor unit of the marine large temperature difference cold seawater unit.

[0009] Preferably, the liquid supply method of the full liquid supply layer is to immerse the metal heat exchanger plates of the plate heat exchanger in the refrigerant. The refrigerant system is equipped with a throttling device to provide a low-temperature and low-pressure refrigerant vapor-liquid mixture, so that the surface heat transfer coefficient of the metal heat exchanger plates is 3 times that of the traditional dry liquid supply method, thereby maximizing the heat exchange efficiency of the plate heat exchanger.

[0010] Preferably, the water flow thermostat on the seawater waterway system is arranged in the middle of the seawater waterway system at the junction of the full liquid supply layer and the dry liquid supply layer. The seawater temperature passing through the water flow thermostat is kept constant at 12°C, so that the uneven cold and hot cold water is mixed here, and the uneven water temperature is mixed here before the next cooling process is carried out, so that the evaporation pressure on the refrigerant side can find a balance point again, and a more sufficient heat and cold exchange can be carried out.

[0011] Preferably, the plate heat exchanger is formed by stacking corrugated metal sheets, and thin rectangular channels are formed between the metal sheets. Heat exchange is performed through the plates, and it has the effects of high heat exchange efficiency, small heat loss and compact structure.

[0012] (3) Beneficial effects

[0013] The plate heat exchanger provided by the present invention is a new type of high-efficiency heat exchanger made of stacked corrugated metal sheets. Thin rectangular channels are formed between various plates, and heat exchange is carried out through the plates. It has the characteristics of high heat exchange efficiency, small heat loss, compact structure, small footprint, easy installation and cleaning, wide application, and long service life. Under the same pressure loss condition, its heat transfer coefficient is 2-3 times higher than that of shell-and-tube heat exchanger, the floor space is more than half of that of tube heat exchanger, and the heat recovery rate can be as high as more than 90%; the refrigerant in the plate heat exchanger is set as a two-way flow, including a full liquid supply layer and a dry liquid supply layer, respectively. The full liquid supply layer accounts for 2 / 3 of the entire refrigerant two-way flow. The full liquid supply method makes the metal heat exchanger of the plate heat exchanger immersed in the refrigerant, and the surface heat transfer coefficient is 3 times that of the traditional dry liquid supply method, which maximizes the heat exchange efficiency of the plate heat exchanger. The dry liquid supply layer accounts for 1 / 3 of the entire refrigerant two-way flow, which can effectively form the effect of dry evaporation and avoid the unevaporated refrigerant returning to the compressor to cause a wet stroke; it can not only obtain the high heat exchange efficiency of the full liquid supply, but also make the refrigerant liquid evaporate completely and become a saturated gas and then return to the compressor unit through the dry liquid supply method, which effectively makes up for the disadvantage that the full liquid supply easily causes the compressor wet stroke and meets the performance effect of the compressor. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 The internal structure flow chart of the plate heat exchanger used in conjunction with a marine large temperature difference cold seawater unit of the present invention.

[0015] Figure numerals: 1 warm water inlet T1, 2 refrigerant inlet S1, 3 cold water outlet T2, 4 refrigerant outlet S2, 5 throttling device, 6 water flow thermostat, 7 full liquid supply layer, 8 dry liquid supply layer. DETAILED DESCRIPTION

[0016] The present invention is further described in conjunction with the accompanying drawings and embodiments.

[0017] In the description of the present invention, it should be understood that the terms "longitudinal", "lateral", "vertical", "horizontal", "up", "down", "front", "back", "left", "right", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0018] like Figure 1As shown, the plate heat exchanger of the present invention is used in conjunction with a marine large temperature difference cold seawater unit. The plate heat exchanger is a new type of high-efficiency heat exchanger formed by stacking a series of metal sheets with a certain arc corrugated shape. Thin rectangular channels are formed between various metal sheets used for heat exchange, and heat is exchanged through the metal sheets. It has the characteristics of high heat exchange efficiency, small heat loss, compact structure, small footprint, easy installation and cleaning, wide application, long service life, etc. Under the same pressure loss, its heat transfer coefficient is 2-3 times higher than that of a shell and tube heat exchanger, and the footprint is more than half of that of a tube heat exchanger. The heat recovery rate can be as high as more than 90%.

[0019] The plate heat exchanger used in conjunction with the marine large temperature difference cold seawater unit has a seawater waterway system composed of T1 (warm water inlet) and T2 (cold water outlet) and a refrigerant system composed of S1 (refrigerant inlet) and S2 (refrigerant outlet), with a total of four interfaces. The waterway system and the refrigerant system together constitute a heat exchange system, and are also equipped with a throttling device 5 and a water flow thermostat 6. The cold water inlet T1 is the inlet of warm water (about 40°C), and T2 flows out cold water of 0°C-2°C after cooling. The refrigerant inlet S1 is connected to the refrigerant outlet of the condenser of the refrigeration unit, and the refrigerant outlet S2 is connected to the compressor unit of the refrigeration unit.

[0020] This patent selects a plate heat exchanger in a marine large temperature difference cold seawater unit, and uses the four-flow flow of the water channel in the plate heat exchanger and the double-flow flow of the refrigerant to achieve more heat exchange time. The double-flow flow of the refrigerant includes a full liquid supply layer and a dry liquid supply layer to achieve more heat exchange time, which can achieve the effect of a large temperature difference. The refrigerant in the plate heat exchanger is set to a double-flow flow type, including a full liquid supply layer and a dry liquid supply layer. The liquid supply method of the first flow is a full liquid supply method, and the first flow accounts for 2 / 3 of the entire refrigerant flow. The full liquid supply method allows the metal heat exchange plate of the plate heat exchanger to be immersed in the refrigerant, and the surface heat transfer coefficient is 3 times that of the traditional dry liquid supply method, which maximizes the heat exchange efficiency of the plate heat exchanger. A throttling device is installed on the refrigerant system for throttling. This section is the second process, which provides a lower temperature and low pressure refrigerant vapor-liquid mixture. The liquid supply method is changed to dry liquid supply. The second process accounts for 1 / 3 of the entire refrigerant process, which can effectively form a dry evaporation effect and prevent the unevaporated refrigerant from returning to the compressor to cause a wet stroke. This combination of full liquid supply and dry liquid supply can achieve the high heat exchange efficiency of full liquid supply in the first process, and the dry liquid supply method of the second process can make the refrigerant liquid evaporate completely and become a saturated gas before returning to the compressor unit, effectively making up for the disadvantage that full liquid supply easily causes a wet stroke of the compressor, and meeting the performance effect of the compressor.

[0021] A water flow thermostat is installed on the refrigerant system to mix the unevenly hot and cold water here, so that the uneven water temperature can be evenly mixed here before the next cooling process is carried out, so that the evaporation pressure on the refrigerant side can find a balance point again and perform more sufficient cold exchange.

[0022] The heat exchange method of the combination of full liquid supply and dry liquid supply on the refrigerant side of the plate heat exchanger has changed the traditional plate heat exchanger which can only supply liquid in dry or full liquid mode, and has carried out effective ratio to enhance the heat exchange effect, because the full liquid supply is easy to cause incomplete evaporation of the refrigerant in the plate heat exchanger, and a large amount of refrigerant liquid returns to the compressor, thereby causing harm to the compressor. However, this new type of plate heat exchanger completely changes the heat exchange method of the traditional plate heat exchanger, combining full liquid supply and dry liquid supply, taking the high heat exchange rate of full liquid supply, and letting the dry liquid supply method to make up for the shortcomings of full liquid heat exchange and liquid supply. This application can increase the inlet and outlet water temperature difference from 20℃ to 40℃, and keep the outlet water temperature between 0~2℃. The plate heat exchanger is used in conjunction with the marine large temperature difference cold seawater unit, which can save costs and reduce energy consumption to the maximum extent, and is matched into the most economical and practical marine large temperature difference cold seawater unit.

[0023] The above embodiments only express the preferred embodiments of the present invention, and the description thereof is relatively specific and detailed, but the present invention is not limited to these embodiments. It should be noted that it is obvious to those skilled in the art. Without departing from the purpose of the present invention, any improvement made shall fall within the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A plate heat exchanger used in conjunction with a marine large temperature difference cold seawater unit, Features: The plate heat exchanger comprises a seawater waterway system consisting of a warm water inlet T1 (1) and a cold water outlet T2 (3), and a refrigerant system consisting of a refrigerant inlet S1 (2) and a refrigerant outlet S2 (4). The seawater waterway system and the refrigerant system together constitute a heat exchange system. The refrigerant in the plate heat exchanger is set to a two-way flow type, including a full liquid supply layer (7) and a dry liquid supply layer (8). The full liquid supply layer (7) accounts for 2 / 3 of the entire refrigerant two-way flow type, and the dry liquid supply layer (8) accounts for 1 / 3 of the entire refrigerant two-way flow type. The refrigerant system is provided with a throttling device (5), and the seawater waterway system is provided with a water flow thermostat (6); The water flow thermostat (6) is arranged in the middle of the seawater channel system at the junction of the full-liquid supply layer (7) and the dry-liquid supply layer (8), and the temperature of the seawater passing through the water flow thermostat (6) is kept constant at 12°C.

2. A plate heat exchanger used in conjunction with a marine large temperature difference cold seawater unit according to claim 1, Features: The seawater channel system converts 40°C seawater sent into the front warm water inlet T1 into 0-2°C cold water that flows out after cooling at the terminal cold water outlet T2 (3). The refrigerant inlet S1 (2) is connected to the refrigerant outlet of the condenser, and the refrigerant outlet S2 (4) is connected to the compressor unit of the marine large temperature difference cold seawater unit.

3. A plate heat exchanger used in conjunction with a marine large temperature difference cold seawater unit according to claim 1 or 2, Features: The liquid supply method of the flooded liquid supply layer (7) is to immerse the metal heat exchange plates of the plate heat exchanger in the refrigerant, and the refrigerant system is equipped with a throttling device (5) to provide a low-temperature and low-pressure refrigerant vapor-liquid mixture.

4. A plate heat exchanger used in conjunction with a marine large temperature difference cold seawater unit according to claim 3, Features: The plate heat exchanger is formed by stacking corrugated metal sheets, and thin rectangular channels are formed between the metal sheets.

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