Marine cold water machine with automatic water replenishment and pressure balance function

Abstract

This utility model discloses a marine chiller with automatic water replenishment and pressure balancing functions. It comprises a refrigeration cycle system consisting of a compressor, plate heat exchanger, throttling device, gas-liquid separator, and water pump, divided into a water-cooled skid and an oil-cooled skid. By installing an expansion tank, adding a water replenishment pipeline, and an automatic water replenishment valve on the water pipeline between the plate heat exchanger and the water pump, automatic water replenishment and water pressure stabilization of the water system are achieved. By adding a bypass pipeline and a flow regulating valve to the oil pipeline, the flow rate and pressure of the lubricating oil in the oil pipeline are effectively regulated. Through this structure, problems such as the inability to automatically replenish water when the water is insufficient, excessively high oil viscosity affecting operation, and uneven pipeline pressure existing in existing marine chiller units are solved. This significantly improves the stability, reliability, and safety of the chiller unit, reduces equipment failure rate, extends equipment service life, reduces energy consumption, and meets the cooling needs of complex marine operating environments.

Description

Technical Field

[0001] This utility model relates to the technical field of marine chiller units, and in particular to a marine chiller with automatic water replenishment and pressure balancing functions. Background Technology

[0002] Marine chillers are key equipment for maintaining stable temperatures in cabins and equipment. A typical chiller system consists of a compressor, evaporator, condenser, and throttling device, forming a refrigeration cycle. Its working principle is as follows: the compressor compresses low-temperature, low-pressure refrigerant gas into high-temperature, high-pressure gas. After liquefying by releasing heat in the condenser, the gas is depressurized by the throttling device and enters the evaporator to absorb heat, ultimately completing the refrigeration cycle.

[0003] However, under the special operating environment of ships (such as swaying, large temperature differences, and limited space), the existing technology has significant drawbacks:

[0004] 1. Defects in the water system: The lack of an automatic water replenishment mechanism can easily lead to insufficient water supply due to cooling water consumption or leakage, resulting in compressor overheating, reduced efficiency, and other malfunctions. The pressure in the pipeline changes drastically due to water temperature fluctuations and water flow impacts (fluctuation range of ±0.15MPa), and long-term stress can easily lead to pipeline rupture or joint leakage.

[0005] 2. Oil circuit system defects: No bypass structure is set up. When the viscosity of the lubricating oil increases (>68cSt), the circulation resistance increases, which aggravates the wear of the compressor. When the unit power changes, the refrigerant flow cannot be adjusted, resulting in frequent start and stop of the compressor (up to 12 times / hour), which increases energy consumption and shortens the equipment life.

[0006] The aforementioned problems severely restrict the reliability and safety of ship chiller units. Therefore, there is an urgent need for an improved solution with automatic water replenishment, oil circuit regulation, and pressure balancing functions. Utility Model Content

[0007] The purpose of this invention is to provide a marine chiller with automatic water replenishment and pressure balancing functions, which can overcome the shortcomings of existing marine chillers.

[0008] To achieve the above objectives, a marine chiller with automatic water replenishment and pressure balancing functions is provided, including a compressor, an oil separator, a condenser, a liquid receiver, a plate heat exchanger, and a water pump. An expansion tank is installed on the water pipeline between the plate heat exchanger and the water pump, and a water replenishment pipeline is installed between the bottom of the expansion tank and an external water source.

[0009] The water supply pipeline is equipped with a ball valve and an automatic water supply valve in sequence. An oil bypass pipeline is installed between the downstream of the compressor oil outlet and the front end of the oil return port. The oil bypass pipeline is equipped with a flow regulating valve to regulate the flow of lubricating oil to balance the oil pressure and viscosity.

[0010] According to the aforementioned marine chiller with automatic water replenishment and pressure balancing functions, the expansion tank is fixedly connected to the water pipeline via a flange or threaded connection. Its pre-charge nitrogen pressure is 80% of the system static pressure. The installation position is lower than the highest point of the water system. It is used to absorb pressure fluctuations caused by temperature changes and water flow fluctuations in the water system, stabilize water pressure, and prevent pipeline damage due to uneven pressure.

[0011] According to the aforementioned marine chiller with automatic water replenishment and pressure balancing functions, the automatic water replenishment valve has a built-in liquid level sensor. The opening and closing logic of the automatic water replenishment valve is as follows: it opens when the water level in the expansion tank is 30% lower than the tank height and closes when it reaches 80%. The water replenishment time is ≤3 minutes. It is used to monitor the water level in the expansion tank and automatically open and close.

[0012] According to the aforementioned marine chiller with automatic water replenishment and pressure balancing functions, the water replenishment pipeline adopts DN15 stainless steel pipe, and the external water source pressure range is 0.2-0.6MPa.

[0013] According to the marine chiller with automatic water replenishment and pressure balancing functions, the oil bypass pipeline adopts a Φ12×1.5mm copper pipe, and its oil outlet connection point is located 50mm downstream of the compressor oil outlet.

[0014] According to the marine chiller with automatic water replenishment and pressure balancing functions, the flow regulating valve is an adjustable valve. When the lubricating oil viscosity is >68cSt or the compressor power fluctuation is >±15%, the opening is set to 30%-50%, so that 20%-40% of the lubricating oil is directly returned.

[0015] According to the marine chiller with automatic water replenishment and pressure balancing functions, the flow regulating valve stabilizes the oil circuit pressure within the range of 0.8-1.2 MPa.

[0016] According to the aforementioned marine chiller with automatic water replenishment and pressure balancing functions, the expansion tank has a volume of 8L and is suitable for a 30HP screw chiller unit.

[0017] This utility model has the following beneficial effects:

[0018] 1. Compared with existing technologies, improvements such as installing an expansion tank and adding a water supply pipeline effectively absorb pressure fluctuations caused by temperature changes and water flow fluctuations in the water system, keeping the water pressure stable. Experiments show that the water pressure fluctuation range is reduced by 80%. On the other hand, the automatic water supply function is realized to ensure the stability of the water volume in the water system, greatly reducing the workload and possible errors of manual water supply. The system water supply volume is reduced from 5L for manual water supply to 0.5L for automatic water supply, a reduction of 90%, which reduces the manual maintenance cost.

[0019] 2. Compared with existing technologies, the addition of a bypass pipeline and flow regulating valve allows for adjustment of the lubricating oil flow in the bypass pipeline based on changes in oil viscosity and compressor power. This reduces oil viscosity fluctuations by 40% and stabilizes the oil pressure within the range of 0.8-1.2 MPa, ensuring normal oil circulation and lubrication. Simultaneously, it effectively regulates refrigerant flow, preventing frequent compressor start-stops caused by unstable refrigerant flow when unit power changes. Experimental results show that the improved system reduces compressor start-stop frequency from 12 times per hour to 3 times per hour, a 75% reduction, thus reducing compressor wear and improving equipment stability and efficiency. Attached Figure Description

[0020] The present invention will be further described below with reference to the accompanying drawings and embodiments;

[0021] Figure 1 This is a schematic diagram of the system structure of a marine chiller with automatic water replenishment and pressure balancing functions according to the present invention.

[0022] Legend:

[0023] 1. Compressor; 2. Oil separator; 3. Condenser; 4. Valve; 5. Liquid receiver; 6. Sight glass; 7. Plate heat exchanger; 8. Expansion tank; 9. Water pump; 10. Water supply line; 11. Ball valve; 12. Automatic water supply valve; 13. Oil bypass line; 14. Flow regulating valve. Detailed Implementation

[0024] This section will describe in detail the specific embodiments of the present utility model. The preferred embodiments of the present utility model are shown in the accompanying drawings. The purpose of the drawings is to supplement the textual description with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the present utility model, but they should not be construed as limiting the scope of protection of the present utility model.

[0025] Reference Figure 1 This utility model discloses a marine chiller with automatic water replenishment and pressure balancing functions, comprising a compressor 1, an oil separator 2, a condenser 3, a liquid receiver 5, a plate heat exchanger 7, and a water pump 9. An expansion tank 8 is installed on the water pipeline between the plate heat exchanger 7 and the water pump 9. The expansion tank 8 is fixedly connected to the water pipeline by means of flange or threaded connection. Its pre-charge nitrogen pressure is 80% of the system static pressure. The installation position is lower than the highest point of the water system. It is used to absorb pressure fluctuations caused by temperature changes and water flow fluctuations in the water system, stabilize water pressure, and prevent pipeline damage due to uneven pressure.

[0026] A water supply pipe 10 is installed between the bottom of the expansion tank 8 and the external water source. A ball valve 11 and an automatic water supply valve 12 are installed on the water supply pipe 10 in sequence. The automatic water supply valve 12 has a built-in liquid level sensor. The opening and closing logic of the automatic water supply valve 12 is as follows: it opens when the water level of the expansion tank 8 is 30% lower than the tank height and closes when it reaches 80%. The water supply time is ≤3 minutes. It is used to monitor the water level of the expansion tank 8 and open and close automatically. An oil bypass pipe 13 is installed between the downstream of the oil outlet of the compressor 1 and the front end of the oil return port. A flow regulating valve 14 is installed on the oil bypass pipe 13 to regulate the flow of lubricating oil to balance the oil pressure and viscosity.

[0027] The expansion tank 8 has a volume of 8L and is connected to the DN50 stainless steel water pipe between the outlet of the plate heat exchanger 7 and the inlet of the water pump 9 via a standard HG / T 20592 flange. The installation position is lower than the highest point of the water system, and the pre-charge nitrogen pressure is 80% of the system static pressure.

[0028] The water supply pipeline 10 is made of DN15 stainless steel pipe. One end is welded to the bottom drain port of the expansion tank 8, and the other end is connected to an external water source with a pressure range of 0.2 to 0.6 MPa. A manual ball valve 11 and an automatic water supply valve 12 are installed in sequence along the flow direction.

[0029] Oil bypass pipeline 13: Φ12×1.5mm copper pipe is used. One end is welded to 50mm downstream of the oil outlet of compressor 1, and the other end is connected to the front end of the oil return port. An adjustable flow regulating valve 14 is installed on the pipeline.

[0030] This utility model of marine chiller, based on the traditional refrigeration cycle, solves the stability problem under special operating conditions of ships by working in concert with an automatic water pressure replenishment system and an oil bypass regulation system. The specific process is as follows:

[0031] I. Basic Refrigeration Cycle

[0032] Compression: Low-temperature, low-pressure refrigerant gas is compressed into high-temperature, high-pressure gas by compressor 1;

[0033] Condensation: High-temperature gas enters the condenser and releases heat to the cooling water, liquefying to form a high-pressure liquid;

[0034] Throttling: After the high-pressure liquid is stabilized by the liquid storage tank 5, it is reduced in pressure to a low-temperature gas-liquid mixture through the throttling device;

[0035] Evaporation: The low-temperature mixture absorbs heat from the cooled medium, such as the circulating water in the compartment, in the plate heat exchanger 7, evaporates into low-temperature gas, and finally returns to the compressor 1 to complete the cycle.

[0036] II. Working Logic of the Automatic Water Pressure Replenishment System

[0037] Pressure balance: When the water circuit experiences pressure fluctuations due to temperature changes or water flow impact, the expansion tank 8 absorbs energy through the contraction / expansion of its internal air bladder, suppressing the water pressure fluctuation range from ±0.15MPa to ±0.03MPa.

[0038] Water level monitoring: The built-in sensor of the automatic water supply valve 12 detects the water level of the expansion tank 8 in real time; Water supply trigger: When the water level is <30% of the tank height, the valve opens and the external water source of 0.2-0.6MPa is injected into the expansion tank through the water supply pipeline 10; Water supply termination: When the water level is ≥80% of the tank height, the valve closes and each water supply lasts ≤3 minutes to ensure a constant water volume in the water circuit.

[0039] III. Working Logic of Oil Circuit Bypass Regulation System

[0040] Anomaly detection: When the lubricating oil viscosity is greater than 68 cSt at 40℃ or the compressor power fluctuation is greater than ±15%, the adjustment requirement is triggered;

[0041] Bypass regulation: Adjust the opening of the flow regulating valve 14 to 30%-50%, so that 20%-40% of the lubricating oil flows directly from the downstream of the oil outlet to the oil return port through the bypass pipeline 13;

[0042] Pressure stabilization: Bypass diversion reduces the flow rate of the main oil circuit, stabilizing the oil pressure at 0.8~1.2MPa, avoiding circulation blockage and compressor wear caused by high viscosity; at the same time, it reduces refrigerant concentration fluctuations and suppresses frequent compressor start-stop from 12 times / hour to 3 times / hour.

[0043] The control group, consisting of the original, unmodified system, was tested under ambient temperature conditions of 25℃±3℃ and a load rate of 80%.

[0044] Performance indicators control group Example Improvement effect Water pressure fluctuation range ±0.15MPa ±0.03MPa Stability improved by 80% Compressor start-stop frequency 12 times / hour 3 times / hour Frequency reduced by 75% Lubricating oil viscosity fluctuation range 52~78cSt 58~65cSt Volatility decreased by 40% System water replenishment 5L / hour 0.5L / hour Water consumption reduced by 90%

[0045] This invention significantly reduces water pressure fluctuations and water replenishment needs through expansion tank pressure balancing and automatic water replenishment functions; oil circuit bypass regulation effectively suppresses viscosity changes, reduces abnormal compressor start-up and shutdown, and comprehensively improves unit reliability.

[0046] The embodiments of the present utility model have been described in detail above with reference to the accompanying drawings. However, the present utility model is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present utility model.

Claims

1. A marine chiller with automatic water replenishment and pressure balancing functions, characterized in that, It includes a compressor (1), an oil separator (2), a condenser (3), a liquid receiver (5), a plate heat exchanger (7), and a water pump (9). An expansion tank (8) is installed on the water pipeline between the plate heat exchanger (7) and the water pump (9). A water supply pipeline (10) is installed between the bottom of the expansion tank (8) and an external water source. The water supply pipeline (10) is provided with a ball valve (11) and an automatic water supply valve (12) in sequence. An oil bypass pipeline (13) is installed between the downstream of the oil outlet of the compressor (1) and the front end of the oil return port. A flow regulating valve (14) is provided on the oil bypass pipeline (13).

2. The marine cold water machine with automatic water replenishment and pressure balance function according to claim 1, characterized in that, The expansion tank (8) is fixedly connected to the water pipeline by means of flange or threaded connection. Its pre-filled nitrogen pressure is 80% of the static pressure of the system, and the installation position is lower than the highest point of the water system.

3. The marine cold water machine with automatic water replenishment and pressure balance function according to claim 1, characterized in that, The automatic water replenishment valve (12) has a built-in liquid level sensor. The opening and closing logic of the automatic water replenishment valve (12) is as follows: it opens when the water level of the expansion tank (8) is 30% lower than the tank height and closes when it reaches 80%. The water replenishment time is ≤3 minutes.

4. The marine cold water machine with automatic water replenishment and pressure balance function according to claim 1, characterized in that, The water supply pipeline (10) is made of DN15 stainless steel and the external water source pressure ranges from 0.2 to 0.6 MPa.

5. The marine cold water machine with automatic water replenishment and pressure balance function according to claim 1, characterized in that, The oil bypass pipeline (13) is made of Φ12×1.5mm copper pipe, and its oil outlet connection point is located 50mm downstream of the oil outlet of the compressor (1).

6. A marine chiller with automatic water replenishment and pressure balancing functions according to claim 1, characterized in that, The flow regulating valve (14) is an adjustable valve. When the lubricating oil viscosity is greater than 68 cSt or the compressor power fluctuation is greater than ±15%, the opening is set to 30%-50% so that 20%-40% of the lubricating oil can be directly returned.

7. The marine cold water machine with automatic water replenishment and pressure balancing function according to claim 1, characterized in that, The flow regulating valve (14) stabilizes the oil circuit pressure within the range of 0.8-1.2 MPa.

8. The marine cold water machine with automatic water replenishment and pressure balancing function according to claim 1, characterized in that, The expansion tank (8) has a volume of 8L and is suitable for 30HP screw refrigeration units.

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