A screw compressor with a double-control solenoid valve for automatically and steplessly adjusting the internal volume ratio efficiently and its control method

Abstract

The present invention relates to a screw compressor with an automatic stepless and efficient adjustment of internal volume ratio and a control method, which is equipped with a double-control solenoid valve. The problems to be solved are as follows: during the adjustment of the internal volume ratio, the compressor cannot maintain a full-load state, and the adjustment accuracy of the two slide valves is relatively poor. The technical key points are as follows: U1 and P are connected to both ends of the H solenoid head, U1 and T are connected to both ends of the A solenoid head, L1 and P are connected to both ends of the G solenoid head, L1 and T are connected to both ends of the B solenoid head, L2 and P are connected to both ends of the F solenoid head, L2 and T are connected to both ends of the C solenoid head, U2 and P are connected to both ends of the E solenoid head, U2 and T are connected to both ends of the D solenoid head, U1 is connected to the a chamber of the energy adjustment piston chamber, L1 is connected to the b chamber of the energy adjustment piston chamber, L2 is connected to the c chamber of the internal volume ratio adjustment piston chamber, U2 is connected to the d chamber of the internal volume ratio adjustment piston chamber, P is connected to the high-pressure oil supply pipeline, and T is connected to the low-pressure chamber. It is applied to a screw compressor with an automatic stepless and efficient adjustment of internal volume ratio.

Description

Technical Field

[0001] The present invention relates to the technical field of refrigeration equipment, and more specifically, to a screw compressor with a double-control solenoid valve for automatically and steplessly adjusting the internal volume ratio and a control method therefor. Background Art

[0002] Energy conservation is the top priority in the energy field. To solve the problem of energy inefficiency caused by over-compression and under-compression of screw compressors, screw compressors capable of adjusting the internal volume ratio have been invented. There are two types of adjustment methods: one is manual stepwise adjustment, and the other is automatic adjustment. Manual stepwise adjustment of the internal volume ratio is applicable to stable working conditions with large seasonal changes between winter and summer, or when there are significant changes in working conditions, such as converting a low-temperature storage to a high-temperature storage. Automatic adjustment of the internal volume ratio can adjust the internal volume ratio in real time according to the changes in the suction and discharge pressures of the screw compressor, that is, it can truly achieve equal internal and external pressure ratios, eliminate over-compression and under-compression, and greatly improve the COP of the compressor. Currently, the common problems in the industry for automatically adjusting the internal volume ratio are as follows: due to the incompressible characteristics of lubricating oil, when the internal volume ratio needs to be adjusted, the internal volume ratio adjustment slide valve and the energy adjustment slide valve separate from the mutually attached state, and the compressor cannot maintain a full-load state, affecting the COP of the compressor; during the process of adjusting the internal volume ratio, the position when the internal volume ratio adjustment slide valve and the energy adjustment slide valve reattach together often deviates. It is difficult for the internal volume ratio slide valve to accurately stop at the required position in one go, and the two slide valves need to continuously correct their positions, or a large deviation amount is set, resulting in poor accuracy of the internal volume ratio adjustment of the compressor. Summary of the Invention

[0003] The object of the present invention is to provide a screw compressor with a double-control solenoid valve for automatically and steplessly adjusting the internal volume ratio efficiently and its control method, so as to solve the problems existing in the background technology: when adjusting the internal volume ratio, the compressor cannot maintain the full-load state, which affects the COP of the compressor; the two slide valves need to be continuously position-corrected, and the accuracy of the internal volume ratio adjustment of the compressor is poor. The technical solution adopted to solve this technical problem is: a screw compressor with a double-control solenoid valve for automatically and steplessly adjusting the internal volume ratio efficiently. The inner cavity of the oil cylinder body is divided into an energy adjustment piston cavity and an internal volume ratio adjustment piston cavity by an intermediate partition. The energy adjustment piston cavity is divided into cavity a and cavity b by an energy adjustment piston. The internal volume ratio adjustment piston cavity is divided into cavity c and cavity d by an internal volume ratio piston. The energy adjustment piston is connected to an energy adjustment slide valve through an energy adjustment guide rod. The internal volume ratio piston is connected to an internal volume ratio slide valve through an internal volume ratio guide rod. It is characterized in that: the double-control solenoid valve is connected to the oil cylinder body. It includes a valve body with six external interfaces and eight electromagnetic heads. Among them, P is the oil inlet, T is the oil outlet, U1, L1, U2, and L2 are four working ports. The two ends of the H electromagnetic head are connected to U1 and P. The two ends of the A electromagnetic head are connected to U1 and T. The two ends of the G electromagnetic head are connected to L1 and P. The two ends of the B electromagnetic head are connected to L1 and T. The two ends of the F electromagnetic head are connected to L2 and P. The two ends of the C electromagnetic head are connected to L2 and T. The two ends of the E electromagnetic head are connected to U2 and P. The two ends of the D electromagnetic head are connected to U2 and T. U1 is connected to cavity a of the energy adjustment piston cavity. L1 is connected to cavity b of the energy adjustment piston cavity. L2 is connected to cavity c of the internal volume ratio adjustment piston cavity. U2 is connected to cavity d of the internal volume ratio adjustment piston cavity. P is connected to the high-pressure oil supply pipeline inside the compressor. T is connected to the low-pressure cavity inside the compressor. A control method for a screw compressor with a double-control solenoid valve for automatically and steplessly adjusting the internal volume ratio efficiently as described above, characterized in that: when the internal volume ratio increases, open the D electromagnetic head, F electromagnetic head, G electromagnetic head, and H electromagnetic head; when the internal volume ratio decreases, open the A electromagnetic head, G electromagnetic head, F electromagnetic head, and E electromagnetic head; when the internal volume ratio reaches the specified position, close all electromagnetic heads. Among them, the double-control solenoid valve is selected to be connected to the oil cylinder body through an external pipeline.

[0004] The beneficial effects of the present invention compared with the prior art are as follows: By adopting the above technical solution, on the one hand, when the content volume ratio increases, open the D solenoid valve and the F solenoid valve, the c chamber is filled with oil and the d chamber returns oil, open the G solenoid valve and the H solenoid valve, the a chamber and the b chamber are connected. Under the combined action of the oil inlet pressure, the oil return pressure, the exhaust pressure and the suction pressure, the content volume ratio slide valve pushes the energy regulating slide valve to move to the right. When the content volume ratio decreases, open the A solenoid valve and the G solenoid valve, the b chamber is filled with oil and the a chamber returns oil, open the E solenoid valve and the F solenoid valve, the c chamber and the d chamber are connected. Under the combined action of the oil inlet pressure, the oil return pressure, the exhaust pressure and the suction pressure, the energy regulating slide valve pushes the content volume ratio slide valve to move to the left. During the process of the content volume change, the two slide valves always remain in contact with each other, that is, when adjusting the content volume ratio under the full load state, the compressor always maintains high efficiency. On the other hand, when the content volume ratio reaches the specified position, close all solenoid valves, and the energy regulating slide valve and the content volume ratio slide valve stop moving while in contact with each other. This greatly reduces the difficulty of program control, enables the screw compressor to obtain the required content volume ratio more quickly and accurately, and is energy-efficient. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] Figure 1 is a schematic diagram of the overall structure of the present invention. Figure 2 is a schematic diagram of the double-control solenoid valve structure. Figure 3 is a schematic diagram of the internal oil circuit structure of the double-control solenoid valve. Figure 4 is a schematic diagram of the internal oil circuit connection of the double-control solenoid valve. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0006] Example 1: Refer to Figure 1 、 Figure 2 、 Figure 3 、 Figure 4, A screw compressor with a double - controlled solenoid valve for automatic stepless and efficient regulation of the internal volume ratio. The inner cavity of the oil cylinder body 1 is divided into an energy regulation piston cavity and an internal volume ratio regulation piston cavity by an intermediate partition 4. The energy regulation piston cavity is divided into cavity a and cavity b by an energy regulation piston 3. The internal volume ratio regulation piston cavity is divided into cavity c and cavity d by an internal volume ratio piston 5. The energy regulation piston 3 is connected to an energy regulation slide valve 9 through an energy regulation guide rod 6. The internal volume ratio piston 5 is connected to an internal volume ratio slide valve 8 through an internal volume ratio guide rod 7. It is characterized in that: The double - controlled solenoid valve 2 is connected to the oil cylinder body 1. It includes a valve body 201 with six external interfaces 202 and eight electromagnetic heads. Among them, P is the oil inlet, T is the oil outlet, U1, L1, U2, and L2 are four working ports. The two ends of the H electromagnetic head 210 are connected to U1 and P. The two ends of the A electromagnetic head 203 are connected to U1 and T. The two ends of the G electromagnetic head 209 are connected to L1 and P. The two ends of the B electromagnetic head 204 are connected to L1 and T. The two ends of the F electromagnetic head 208 are connected to L2 and P. The two ends of the C electromagnetic head 205 are connected to L2 and T. The two ends of the E electromagnetic head 207 are connected to U2 and P. The two ends of the D electromagnetic head 206 are connected to U2 and T. U1 is connected to cavity a of the energy regulation piston cavity. L1 is connected to cavity b of the energy regulation piston cavity. L2 is connected to cavity c of the internal volume ratio regulation piston cavity. U2 is connected to cavity d of the internal volume ratio regulation piston cavity. P is connected to the high - pressure oil supply pipeline inside the compressor. T is connected to the low - pressure cavity inside the compressor.

[0007] A control method for a screw compressor with a double - controlled solenoid valve for automatic stepless and efficient regulation of the internal volume ratio as described above, characterized in that: When the internal volume ratio increases, open the D electromagnetic head 206, F electromagnetic head 208, G electromagnetic head 209, and H electromagnetic head 210; When the internal volume ratio decreases, open the A electromagnetic head 203, G electromagnetic head 209, F electromagnetic head 208, and E electromagnetic head 207; When the internal volume ratio reaches the specified position, close all electromagnetic heads. Among them, the double - controlled solenoid valve 2 selects an external pipeline to be connected to the oil cylinder body 1.

Claims

1. A screw compressor with a double-controlled solenoid valve for automatically and steplessly adjusting the internal volume ratio efficiently. The inner cavity of the oil cylinder body (1) is separated into an energy regulation piston cavity and an internal volume ratio regulation piston cavity by an intermediate partition (4). The energy regulation piston cavity is separated into cavity a and cavity b by an energy regulation piston (3). The internal volume ratio regulation piston cavity is separated into cavity c and cavity d by an internal volume ratio piston (5). The energy regulation piston (3) is connected to an energy regulation slide valve (9) through an energy regulation guide rod (6). The internal volume ratio piston (5) is connected to an internal volume ratio slide valve (8) through an internal volume ratio guide rod (7). It is characterized in that: The dual-control solenoid valve (2) is connected to the oil cylinder body (1). It includes a valve body (201) with six external interfaces (202) and eight electromagnetic heads. Among them, P is the oil inlet, T is the oil outlet, U1, L1, U2, and L2 are four working ports. The two ends of the H electromagnetic head (210) are connected to U1 and P, the two ends of the A electromagnetic head (203) are connected to U1 and T, the two ends of the G electromagnetic head (209) are connected to L1 and P, the two ends of the B electromagnetic head (204) are connected to L1 and T, the two ends of the F electromagnetic head (208) are connected to L2 and P, the two ends of the C electromagnetic head (205) are connected to L2 and T, the two ends of the E electromagnetic head (207) are connected to U2 and P, and the two ends of the D electromagnetic head (206) are connected to U2 and T. U1 is connected to the a chamber of the energy regulation piston chamber, L1 is connected to the b chamber of the energy regulation piston chamber, L2 is connected to the c chamber of the internal volume ratio regulation piston chamber, U2 is connected to the d chamber of the internal volume ratio regulation piston chamber, P is connected to the high-pressure oil supply pipeline in the compressor, and T is connected to the low-pressure chamber in the compressor.

2. The automatic stepless high-efficiency capacity ratio regulating screw compressor with a double-control solenoid valve according to claim 1, wherein: The dual-control solenoid valve (2) is selected to be connected to the oil cylinder body (1) through an external pipeline.

3. A control method for a screw compressor with an automatically and steplessly adjustable internal volume ratio and a double-control solenoid valve as described in claim 1, characterized in that: When the internal volume ratio increases, the D electromagnetic head (206), F electromagnetic head (208), G electromagnetic head (209), and H electromagnetic head (210) are opened; when the internal volume ratio decreases, the A electromagnetic head (203), G electromagnetic head (209), F electromagnetic head (208), and E electromagnetic head (207) are opened; when the internal volume ratio reaches the specified position, all electromagnetic heads are closed.

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