Oil tank pressure regulating system and centrifugal water chilling unit

Abstract

The utility model provides an oil tank pressure adjusting system and a centrifugal water chilling unit. According to one embodiment of the invention, the oil tank pressure regulating system comprises a centrifugal compressor, a pressure regulating device and a pressure regulating device, the centrifugal compressor comprises a bearing cavity, a motor cavity and a bearing arranged in the bearing cavity, and the pressure in the motor cavity is larger than that in the bearing cavity; the oil tank comprises an oil supply port, an oil return port and an exhaust port, the oil supply port is communicated with the bearing and used for lubricating the bearing, and the oil return port is communicated with the bearing cavity; and the first auxiliary compressor is communicated with the exhaust port and is used for being communicated to an evaporator. According to the scheme, the pressure in the oil tank can be reduced, and then the solubility of a refrigerant in lubricating oil is reduced.

Description

Technical Field

[0001] The present application relates to the technical field of refrigeration equipment, and in particular to an oil tank pressure regulating system and a centrifugal chiller. Background Art

[0002] In centrifugal chillers, components such as bearings of centrifugal evaporators require lubricating oil of a certain viscosity to form a good oil film to reduce friction and wear.

[0003] When a centrifugal chiller operates at high evaporator outlet water flow, the evaporator pressure and oil tank pressure are significantly higher than in comfort cooling conditions. Under these conditions, the solubility of the refrigerant in the oil increases, the oil concentration decreases, and the oil viscosity also decreases. This results in a decrease in the oil's lubrication effectiveness and the risk of increased bearing wear in the centrifugal compressor. Utility Model Content

[0004] The present application provides an oil tank pressure regulating system and a centrifugal chiller, which can reduce the pressure in the oil tank and reduce the solubility of the refrigerant in the lubricating oil.

[0005] In a first aspect, the present application provides a fuel tank pressure regulating system, comprising:

[0006] A centrifugal compressor comprises a bearing cavity, a motor cavity and a bearing disposed in the bearing cavity, wherein the pressure in the motor cavity is greater than the pressure in the bearing cavity;

[0007] an oil tank comprising an oil supply port, an oil return port, and an exhaust port, wherein the oil supply port is communicated with the bearing for lubricating the bearing, and the oil return port is communicated with the bearing cavity; and

[0008] The first auxiliary compressor is communicated with the exhaust port and is used to be connected to the evaporator.

[0009] Optionally, the oil return port and the bearing cavity are communicated with each other through an oil return pipeline, and a first regulating device is connected to the oil return pipeline, and the first regulating device is used to regulate the flow of the oil-gas mixture in the oil return pipeline.

[0010] Optionally, the oil tank pressure regulating system also includes an oil separator connected to the oil return pipeline, the oil separator including an oil separator inlet, an oil separator outlet and an oil separator gas outlet, the oil separator inlet is connected to the bearing cavity, the oil separator outlet is connected to the oil return port, and the oil separator gas outlet is used to connect to the evaporator; wherein, the first regulating device is located between the oil separator outlet and the oil return port.

[0011] Optionally, the oil tank pressure regulating system further includes a second auxiliary compressor, which is connected to the oil separator outlet and is used to be connected to the evaporator.

[0012] Optionally, the oil tank pressure regulating system further includes a second regulating device, which is connected to the oil return line and is located between the oil separator and the bearing cavity.

[0013] Optionally, the first regulating device is an orifice plate or a regulating valve; or

[0014] When the oil tank pressure regulating system further includes a second regulating device, at least one of the first regulating device and the second regulating device is an orifice plate or a regulating valve.

[0015] Optionally, the fuel tank pressure regulation system also includes a control module and a pressure sensor installed on the fuel tank, the control module is connected to the pressure sensor and the first auxiliary compressor respectively, the pressure sensor is used to detect the pressure information in the fuel tank and generate a pressure signal, and the control module is used to control the operation of the first auxiliary compressor according to the pressure signal.

[0016] Optionally, the control module is used to determine whether the pressure in the oil tank is within a preset pressure range. If the pressure is within the preset pressure range, the control module controls the first auxiliary compressor to execute a target instruction; wherein, the target instruction includes one of start, regulation, shutdown and bypass.

[0017] In a second aspect, the present application provides a centrifugal chiller, comprising:

[0018] A fuel tank pressure regulating system as described in any one of the above.

[0019] The centrifugal chiller and oil tank pressure regulating system provided by this application have at least the following advantages:

[0020] The first auxiliary compressor is connected to the exhaust port of the oil tank. By extracting the refrigerant gas in the oil tank, the pressure inside the oil tank is reduced, causing the refrigerant dissolved in the lubricating oil to flash into gas and precipitate, thereby reducing the solubility of the refrigerant in the lubricating oil and increasing the viscosity of the lubricating oil, so that the lubricating oil can normally lubricate bearings and other components. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a structural schematic diagram of a fuel tank pressure regulating system shown in an embodiment;

[0022] Figure 2 It is a structural schematic diagram of a fuel tank pressure regulating system with a regulating device shown in an embodiment;

[0023] Figure 3 is a structural schematic diagram of an oil tank pressure regulating system with an oil separator shown in an embodiment;

[0024] Figure 4 is a structural schematic diagram of an oil tank pressure regulating system with an oil separator shown in yet another embodiment;

[0025] Figure 5 This is a control logic structure diagram of a fuel tank pressure regulation system shown in an embodiment.

[0026] Description of reference numerals:

[0027] 10. Centrifugal compressor; 11. Bearing; 12. Bearing cavity; 13. Shaft seal; 14. Motor cavity; 20. Oil tank; 30. First auxiliary compressor; 40. First regulating device; 50. Oil separator; 60. Second auxiliary compressor; 70. Second regulating device; 81. Oil supply line; 82. Oil return line; 91. Pressure sensor; 92. Control module. DETAILED DESCRIPTION

[0028] Here, the technical solutions in the embodiments (or "implementations") of the present application will be clearly and completely described in conjunction with the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements.

[0029] If there are terms related to directional indications or positional relationships in the embodiments of this application (such as up, down, left, right, front, back, inside, outside, top, bottom, center, vertical, horizontal, longitudinal, transverse, length, width, counterclockwise, clockwise, axial, radial, circumferential, etc.), such terms are only used to explain the relative positional relationship, movement, etc. between the components in a specific posture (as shown in the accompanying drawings); if the specific posture changes, the directional indication or positional relationship will also change accordingly. In addition, the terms "first" and "second" in the embodiments of this application are only used for the purpose of convenience of description and should not be understood as indicating or implying relative importance.

[0030] The present application provides an oil tank pressure regulating system and a centrifugal chiller. The oil tank pressure regulating system and the centrifugal chiller are described in detail below with reference to the accompanying drawings.

[0031] refer to Figure 1 The embodiment of the present application provides an oil tank pressure regulating system, which can reduce the pressure of the oil tank 20 under specific working conditions (especially high evaporator water outlet conditions), thereby reducing the solubility of the refrigerant in the lubricating oil.

[0032] The oil tank pressure regulating system includes a centrifugal compressor 10 , an oil tank 20 and a first auxiliary compressor 30 .

[0033] Centrifugal compressor 10 includes a bearing cavity 12, a bearing 11 disposed within bearing cavity 12, and a motor cavity 14. The pressure within motor cavity 14 is greater than the pressure within bearing cavity 12 to prevent lubricating oil from flowing into motor cavity 14 and causing oil loss. At the same time, some refrigerant gas within motor cavity 14 may leak into bearing cavity 12 through shaft seal 13 of bearing 11. In other embodiments, shaft seal 13 is not required.

[0034] The oil tank 20 includes an oil supply port, an oil return port, and an exhaust port. The oil supply port is connected to the bearing 11 and is used to deliver lubricating oil to the bearing 11 for lubrication. The oil return port is connected to the bearing cavity 12, allowing the oil-gas mixture (lubricating oil and refrigerant gas) in the bearing cavity 12 to flow back into the oil tank 20 through the oil return port. The first auxiliary compressor 30 is connected to the exhaust port and is connected to the evaporator. The refrigerant gas flowing back into the oil tank 20 from the oil return port can flow into the first auxiliary compressor 30 through the exhaust port of the oil tank 20 and then be delivered to the evaporator.

[0035] From the above description, it can be seen that the first auxiliary compressor 30 is connected to the exhaust port of the oil tank 20, so as to extract the refrigerant gas accumulated in the oil tank 20, reduce the pressure inside the oil tank 20, and make the refrigerant dissolved in the lubricating oil flash into gas and precipitate, thereby reducing the solubility of the refrigerant gas in the lubricating oil, increasing the viscosity of the lubricating oil, and allowing the lubricating oil to normally lubricate components such as the bearing 11.

[0036] In one embodiment, the first auxiliary compressor 30 is a rotary compressor. Rotary compressors have a relatively simple structure and fewer moving parts. Compared to compressors with complex structures, the interactions between components and potential points of failure are also reduced. Therefore, this solution uses a rotary compressor as the first auxiliary compressor to save space and improve its reliability and lifespan during operation. In other embodiments, the first auxiliary compressor 30 can also be a piston compressor, a screw compressor, a scroll compressor, a centrifugal compressor, etc.

[0037] It should be noted that the specific structures of the above-mentioned rotary compressors, piston compressors, screw compressors, scroll compressors, centrifugal compressors and other devices can refer to relevant technologies, and this application does not make specific limitations on this.

[0038] In one embodiment, the power of the rotary compressor is 40 to 300 W. It is easy to understand that the refrigerant discharged from the exhaust port of the oil tank 20 is usually small. Therefore, in this embodiment, the power of the rotary compressor is set between 40W and 300W, which can better match its needs and avoid waste caused by excessive power. At the same time, a rotary compressor with moderate power is relatively economical in procurement cost, and will not lead to a significant increase in equipment cost due to excessive power requirements. For example, the power of the rotary compressor can be 40W, 100W, 200W, 300W, but is not limited to this.

[0039] refer to Figure 2 In one embodiment, the oil supply port of the oil tank 20 is connected to the bearing 11 through an oil supply line 81, and the oil return port of the oil tank 20 is connected to the bearing cavity 12 through an oil return line 82. A first regulating device 40 is connected to the oil return line 82. The first regulating device 40 is used to regulate the flow rate of the oil-gas mixture in the oil return line 82, and thus to regulate the pressure in the bearing cavity 12 to prevent the pressure in the bearing cavity 12 from being too low, which may cause excessive refrigerant gas in the motor cavity 14 of the centrifugal compressor 10 to leak into the bearing cavity 12 through the shaft seal 13.

[0040] The first regulating device 40 may be an orifice plate or a regulating valve, thereby regulating the flow rate of the oil-gas mixture in the oil return line 82 and, in turn, regulating the pressure within the bearing cavity 12. It should be noted that when the first regulating device 40 is an orifice plate, those skilled in the art may select different models of orifice plates to regulate the pressure within the bearing cavity 12 according to different pressure conditions.

[0041] refer to Figure 3 In one embodiment, the oil tank pressure regulation system further includes an oil separator 50 connected to the oil return line 82. The oil separator 50 includes an oil separator inlet, an oil separator outlet, and an oil separator gas outlet. The oil separator inlet communicates with the bearing cavity 12, the oil separator outlet communicates with the oil return port, and the oil separator gas outlet is connected to the evaporator. In other words, an oil separator 50 is further provided between the oil return port of the oil tank 20 and the bearing cavity 12. The oil separator 50 can separate the lubricating oil and refrigerant in the oil-gas mixture flowing out of the bearing cavity 12 as much as possible, allowing the lubricating oil in the oil return line 82 to flow smoothly back to the oil tank 20. This reduces the amount of refrigerant gas carried in the lubricating oil, thereby reducing the load on the first auxiliary compressor 30.

[0042] Among them, the first regulating device 40 is located between the oil outlet and the oil return port of the oil tank 20 to regulate the flow of the return oil line 82 between the oil outlet of the oil separator 50 and the oil return port of the oil tank 20, so that the lubricating oil in the oil separator 50 is at a reasonable liquid level, ensuring that there is a reliable liquid seal in the return oil line 82 or the oil separator 50, and ensuring that the refrigerant gas that is not dissolved in the lubricating oil can enter the evaporator at the oil separator 50. In this way, the first auxiliary compressor 30 only needs to process the refrigerant gas dissolved in the lubricating oil to reduce the load of the first auxiliary compressor 30, thereby reducing the selection size of the first auxiliary compressor 30.

[0043] refer to Figure 4 In one embodiment, the oil tank pressure regulation system further includes a second auxiliary compressor 60, which is connected to the oil separator outlet of the oil separator 50 and is connected to the evaporator. Similar to the first auxiliary compressor 30, the second auxiliary compressor 60 can extract and compress the refrigerant gas in the oil separator 50, which helps to reduce the pressure inside the oil separator 50 and thereby reduce the solubility of the refrigerant gas in the lubricating oil in the oil separator 50.

[0044] Furthermore, the oil tank pressure regulating system also includes a second regulating device 70, which is connected to the return oil line 82 and is located between the oil separator 50 and the bearing cavity 12 to regulate the flow rate of the oil-gas mixture in the return oil line 82 between the oil inlet of the oil separator 50 and the bearing cavity 12, thereby regulating the pressure in the bearing cavity 12 and thus regulating the amount of leakage.

[0045] The second adjusting device 70 may be the same as the first adjusting device 40 , that is, the second adjusting device 70 is also a perforated plate or an adjusting plate.

[0046] refer to Figure 5 In one embodiment, the fuel tank pressure regulation system further includes a control module 92 and a pressure sensor 91 installed in the fuel tank 20. The control module 92 is connected to the pressure sensor 91 and the first auxiliary compressor 30 respectively. The pressure sensor 91 is used to detect the pressure information in the fuel tank 20 and generate a pressure signal. The control module 92 is used to control the operation of the first auxiliary compressor 30 according to the value of the pressure signal. The pressure sensor 91 can detect the pressure value in the fuel tank 20 in real time and convert it into a pressure signal. This enables the system to promptly understand the changes in the pressure in the fuel tank 20. The control module 92 accurately controls the operation of the first auxiliary compressor 30 according to the pressure signal value transmitted by the pressure sensor 91 to adjust the pressure in the fuel tank 20.

[0047] The control module 92 may be, but is not limited to, a PLC (Programmable Logic Controller), an integrated circuit module, or a single chip microcomputer. The pressure sensor 91 may be, but is not limited to, a strain gauge pressure sensor, a piezoresistive pressure sensor, or a capacitive pressure sensor.

[0048] In a specific embodiment, the control module 92 is used to determine whether the pressure in the oil tank 20 is within a preset pressure range. If the pressure is within the preset pressure range, the control module 92 controls the first auxiliary compressor 30 to execute a target instruction; wherein the target instruction includes one of start, adjustment, shutdown and bypass.

[0049] The preset pressure range is related to the refrigerant's composition and temperature, and this application does not specifically limit this. However, for ease of understanding, this embodiment provides a specific solution. For example, at 7°C, the preset pressure range is: refrigerant saturation pressure ±5%. That is, for a refrigerant saturation pressure of P, the preset pressure range is: 0.95P to 1.05P.

[0050] In the above target command, “start” means controlling the first auxiliary compressor 30 to start operating.

[0051] “Adjustment” refers to adjusting the power of the first auxiliary compressor 30 when the first auxiliary compressor 30 is already running.

[0052] “Shutdown” means controlling the first auxiliary compressor 30 to stop running.

[0053] “Bypass” means that the exhaust port of the oil tank 20 bypasses the first auxiliary compressor 30 and is directly connected to the evaporator through a bypass pipe (not shown).

[0054] An embodiment of the present application also provides a centrifugal chiller, comprising the oil tank pressure regulating system described in any of the above embodiments.

[0055] The centrifugal chiller can also include a condenser and an evaporator. The refrigerant compressed by the centrifugal compressor 10 and / or the first auxiliary compressor 30 can be connected to the condenser, transported into the evaporator through the condenser, and returned to the centrifugal compressor 10 from the evaporator to form a refrigeration cycle system.

[0056] It should be noted that the technical solutions or technical features described in the above embodiments can be combined or supplemented with each other without conflict. The scope of protection of this application is not limited to the precise structures described in the above embodiments and shown in the accompanying drawings; all modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of this application shall be included in the scope of protection of this application.

Claims

1. A fuel tank pressure regulating system, characterized in that: include: A centrifugal compressor (10) comprises a bearing cavity (12), a motor cavity (14), and a bearing (11) disposed in the bearing cavity (12), wherein the pressure in the motor cavity (14) is greater than the pressure in the bearing cavity (12); an oil tank (20), comprising an oil supply port, an oil return port, and an exhaust port, wherein the oil supply port is communicated with the bearing (11) for lubricating the bearing (11), and the oil return port is communicated with the bearing cavity (12); and The first auxiliary compressor (30) is communicated with the exhaust port and is used to be connected to the evaporator.

2. The fuel tank pressure regulating system according to claim 1, characterized in that: The oil return port and the bearing cavity (12) are communicated via an oil return pipeline (82). A first regulating device (40) is connected to the oil return pipeline (82). The first regulating device (40) is used to regulate the flow of the oil-gas mixture in the oil return pipeline (82).

3. The fuel tank pressure regulating system according to claim 2, characterized in that: The oil tank pressure regulating system further comprises an oil separator (50) connected to the oil return line (82), the oil separator (50) comprising an oil separator inlet, an oil separator outlet and an oil separator gas outlet, the oil separator inlet being in communication with the bearing cavity (12), the oil separator outlet being in communication with the oil return port, and the oil separator gas outlet being used to be in communication with an evaporator; wherein the first regulating device (40) is located between the oil separator outlet and the oil return port.

4. The fuel tank pressure regulating system according to claim 3, characterized in that: The oil tank pressure regulating system further comprises a second auxiliary compressor (60), wherein the second auxiliary compressor (60) is communicated with the oil separation outlet and is used to be connected to the evaporator.

5. The fuel tank pressure regulating system according to claim 4, characterized in that: The oil tank pressure regulating system further comprises a second regulating device (70), which is connected to the oil return line (82) and is located between the oil separator (50) and the bearing cavity (12).

6. The fuel tank pressure regulating system according to any one of claims 2 to 5, characterized in that: The first regulating device (40) is an orifice plate or a regulating valve; or When the oil tank pressure regulating system further includes a second regulating device (70), at least one of the first regulating device (40) and the second regulating device (70) is an orifice plate or a regulating valve.

7. The fuel tank pressure regulating system according to any one of claims 1 to 5, characterized in that: The fuel tank pressure regulation system further comprises a control module (92) and a pressure sensor (91) installed on the fuel tank (20), wherein the control module (92) is connected to the pressure sensor (91) and the first auxiliary compressor (30) respectively, wherein the pressure sensor (91) is used to detect pressure information in the fuel tank (20) and generate a pressure signal, and the control module (92) is used to control the operation of the first auxiliary compressor (30) according to the pressure signal.

8. The fuel tank pressure regulating system according to claim 7, characterized in that: The control module (92) is used to determine whether the pressure in the oil tank (20) is within a preset pressure range, and if the pressure is within the preset pressure range, control the first auxiliary compressor (30) to execute a target instruction; The target instruction includes one of start, adjustment, shutdown and bypass.

9. The fuel tank pressure regulating system according to any one of claims 1 to 5 and 8, characterized in that: The first auxiliary compressor (30) is a rotary compressor, and the power of the rotary compressor is 40 to 300W.

10. A centrifugal chiller, characterized in that: include: The fuel tank pressure regulating system according to any one of claims 1 to 9.

Images