Volume ratio slide valve adjusting device, single-machine two-stage screw compressor and air conditioning unit

Abstract

The utility model discloses a volume ratio slide valve adjusting device, a single-machine two-stage screw compressor and an air conditioning unit. The volume ratio slide valve adjusting device comprises an oil cylinder, an oil piston, a slide valve rod, a slide valve, a loading electromagnetic valve and an unloading electromagnetic valve, wherein the slide valve rod and the slide valve are sequentially connected with one side of the oil piston, and the loading electromagnetic valve and the unloading electromagnetic valve are communicated with the oil cylinder. A spring is arranged between the other side face of the oil piston and the oil cylinder, and the unloading electromagnetic valve enables the oil cylinder to be communicated with the low-pressure stage of the single-machine two-stage screw compressor. The volume ratio slide valve adjusting device is applied to a single-machine two-stage screw compressor, and the size of the high-pressure stage Vi of the compressor can be adjusted in time according to needs, that is, the volume ratio slide valve adjusting device can be adjusted to the position of the minimum Vi under the working condition of a small pressure ratio. And after the compressor is shut down, the compressor can be automatically adjusted to be in a small Vi state, so that unloading starting is facilitated. And meanwhile, the high-pressure stage Vi can be stably and reliably increased, so that the matching of the pressure ratio of the compressor is effectively realized, and the efficiency of the compressor is improved.

Description

Technical Field

[0001] The utility model relates to fluid conveying equipment, in particular to a high-pressure stage volume ratio slide valve regulating device, a single-stage two-stage screw compressor with the slide valve regulating device, and an air-conditioning unit. Background Technique

[0002] Single-stage two-stage screw compressors have been increasingly widely used in the fields of water cooling, refrigeration, and cold storage due to their large pressure ratio range and the ability to improve their performance through intermediate gas injection. However, since single-stage two-stage screw compressors have two pairs of screw rotors, namely a low-pressure stage and a high-pressure stage, their load regulation and high-pressure stage volume ratio (the ratio of the high-pressure stage suction volume to the discharge volume Vi, that is, suction volume / discharge volume) regulation are relatively complex. Usually, the load is regulated by adjusting the speed of the motor to achieve the matching of the required refrigerating capacity; the Vi of the high-pressure stage is regulated by adjusting the position of the slide valve of the high-pressure stage to achieve the matching of the compressor pressure ratio and improve the compressor efficiency. Conventionally, the position of the slide valve of the high-pressure stage can be controlled by controlling the pressure difference between the two sides of the oil piston in the oil cylinder.

[0003] As Figure 1 shown is a schematic diagram of the working principle of an existing single-stage two-stage screw compressor. Figure 2The figure shows a cross-sectional view of the high-pressure stage of an existing single-stage two-stage screw compressor. This type of screw compressor includes a housing, a motor 10, a first-stage compression screw rotor 2, a second-stage compression screw rotor 3, and a slide valve regulating mechanism for the high-pressure stage volume ratio (Vi) arranged in the housing from right to left in sequence. On the right side of the compressor is the suction port 1 of the first-stage compression screw rotor, that is, the low-pressure stage suction port, with a pressure of Ps; between the first-stage compression screw rotor 2 and the second-stage compression screw rotor 3 is the intermediate pressure stage, with a pressure of Pm, which is the first-stage discharge pressure and also the second-stage suction pressure; the end of the second-stage compression screw rotor 3 is the high-pressure stage, with a pressure of the second-stage discharge pressure Pd, which is also the total discharge pressure of the compressor, and the gas in the high-pressure stage is discharged through the exhaust port 7. The high-pressure stage Vi slide valve regulating mechanism includes a slide valve 8 for high-pressure stage capacity regulation and a slide valve rod 11. The right end of the slide valve rod is fixed to the left end of the slide valve, and the left end of the slide valve rod extends out of the housing and is connected to an oil piston 6 in an oil cylinder 5. A spring 4 is sleeved on the slide valve rod between the oil piston and the housing wall. Pressure oil can be input into the oil cylinder through a loading solenoid valve V1, with an oil pressure of Po; the pressure oil in the oil cylinder can be input into the intermediate pressure stage in the compressor through an unloading solenoid valve V2. When pressure oil is input into the oil cylinder through the loading solenoid valve V1, the unloading solenoid valve V2 is closed. The pressure on the left side of the oil piston 6 is greater than that on the right side, so the oil piston 6 pushes the slide valve rod 11 and the slide valve 8 to move towards the intermediate pressure stage on the right side, and the high-pressure stage volume ratio Vi gradually becomes smaller. When the loading solenoid valve V1 is closed and the unloading solenoid valve V2 is opened, the pressure oil in the oil cylinder 5 is input into the intermediate pressure stage of the compressor through a pipeline 9. At this time, the oil pressure on the left side of the oil piston drops, while the pressure of the intermediate pressure stage of the compressor rises. Therefore, the pressure on the right side of the oil piston is greater than that on the left side, causing the oil piston 6 to pull the slide valve rod 11 and the slide valve 8 to move towards the left side, and in this way, Vi can be made larger again. The slide valve regulating mechanism uses the pressure difference on both sides of the oil piston to drive the slide valve to move left and right, thereby implementing the regulation of the high-pressure stage volume ratio to achieve the matching of the compressor pressure ratio and improve the compressor efficiency.

[0004] Further, a precise analysis is carried out on the force for driving and regulating the movement of the slide valve by the slide valve regulating mechanism of the existing single-stage two-stage screw compressor. As Figure 2 shown, when the single-stage two-stage screw compressor requires a small Vi, the loading solenoid valve V1 can be opened to supply oil to the oil cylinder 5. At this time, the pressure Po in the oil cylinder is approximately equal to the discharge pressure Pd, that is, Po≈Pd. Then the combined force on the oil piston 6, the slide valve rod 11, and the slide valve 8 is:

[0005] (The oil cylinder pressure Po × the pressure-receiving area S1 on the left side of the oil piston) - (The discharge pressure Pd × the pressure-receiving area S2 on the right side of the oil piston) + (The discharge pressure Pd × the pressure-receiving area S3 on the left side of the slide valve) - (The intermediate pressure stage pressure Pm × the pressure-receiving area S4 on the right side of the slide valve) - The spring force Fs - The frictional force Fn.

[0006] Since Po≈Pd, the comprehensive force is simplified to Po(S1-S2+S3)-PmXS4-Fs-Fn, from Figure 2 It can be seen from the figure that S1>S2>S3≈S4. Since Po>Pm, the total force generated by the pressure difference on the left and right sides of the oil piston is usually above 1kN and is greater than the sum of the spring force Fs and the friction force Fn. The slide valve 8 is forced to move to the right, making the high-pressure stage exhaust volume larger, and Vi becomes smaller.

[0007] When the demand for a single two-stage screw compressor is large Vi, the unloading solenoid valve V2 is opened to unload the oil, and the loading solenoid valve V1 is closed. Since the oil cylinder is connected to the medium pressure stage, the oil cylinder pressure Po is approximately equal to the medium pressure stage pressure Pm, that is, Po≈Pm, so the combined force of the oil piston, the sliding valve rod and the sliding valve is:

[0008] (Medium pressure stage pressure PmX pressure area on the right side of slide valve S4) - (cylinder pressure PoX pressure area on the left side of oil piston S1) + (exhaust pressure PdX pressure area on the right side of oil piston S2) - (exhaust pressure PdX pressure area on the left side of slide valve S3) + spring force Fs - friction force Fn.

[0009] At this time, the comprehensive force can be converted into: PdX(S2-S3)-Pm(S1-S4)+Fs-Fn. Although S2 is slightly smaller than S1, Pd is significantly larger than Pm, and the spring force is greater than the friction force. At this time, the slide valve 8 is forced to move to the left, making the high-pressure stage exhaust volume smaller, and Vi becomes larger.

[0010] However, the adjustment method of the above slide valve is not suitable for a single two-stage screw compressor under a small pressure ratio (pressure ratio: high-pressure stage exhaust pressure / suction pressure, i.e. Pd / Pm). For example, when Vi is close to 1 (high-pressure stage suction volume ≈ exhaust volume), the high-pressure stage only plays a role in gas transportation and basically does not play a role in compressing gas. That is, the suction and exhaust pressure difference of the high-pressure stage is close to 0, i.e. Pd≈Pm (small pressure ratio), open the loading solenoid valve V1 to add oil, i.e. Po≈Pd≈Pm, and S3≈S4. At this time, the comprehensive force loaded by the slide valve 8 is: Pm(S1-S2)-Fs-Fn.

[0011] In this way, it is easy for the pressure difference on both sides of the oil piston to generate a force smaller than the sum of the spring force Fs and the friction force Fn, and the slide valve cannot move to the right to the minimum Vi position, that is, the slide valve cannot be loaded and adjusted to the designed minimum Vi. When the compressor is shut down, it cannot automatically adjust to the small Vi state to start unloading. Such a structure is not conducive to matching the compressor pressure ratio and improving the efficiency of the compressor. The unloading oil circuit in the prior art is connected to the medium pressure stage. Since the pressure Pm of the medium pressure stage is relatively large, the oil in the cylinder cannot enter the medium pressure area as soon as possible to form an ideal pressure difference to push the slide valve to the left. Therefore, the slide valve unloading is unreliable and cannot be adjusted to a larger Vi in time to achieve the matching of the compressor pressure ratio.

[0012] Therefore, how to overcome the defect that the existing single-stage compression screw compressor cannot be conveniently and reliably adjusted to the required high-pressure stage volume ratio is a technical problem that needs to be solved as soon as possible in this field. Utility Model Content

[0013] The utility model aims to solve the technical problem that the existing single-stage two-stage screw compressor cannot be conveniently and reliably adjusted to the required high-pressure stage volume ratio, and provides a slide valve regulating device that can be conveniently and reliably adjusted to the required Vi, a single-stage compression screw compressor with the slide valve regulating device, and an air-conditioning unit.

[0014] A volume ratio slide valve regulating device provided by the utility model includes an oil cylinder and an oil piston, a slide valve rod and a slide valve sequentially connected to one side surface of the oil piston, a loading solenoid valve and an unloading solenoid valve communicated with the oil cylinder. A spring is arranged between the other side surface of the oil piston and the oil cylinder, and the unloading solenoid valve communicates the oil cylinder with the low-pressure stage of the single-stage two-stage screw compressor.

[0015] Preferably, the oil cylinder includes a cylinder body and an oil cylinder cover, and the spring is arranged between the inner side of the oil cylinder cover and the oil piston.

[0016] Preferably, two shaft sections with different diameters extend outward from the inner side surface of the oil cylinder cover, the shaft sections are hollow, and through holes are arranged around the small-diameter shaft section.

[0017] Preferably, the side surface of the oil piston against the spring is provided with an inward concave ring.

[0018] Preferably, one end of the spring is sleeved on the small-diameter shaft section of the oil cylinder cover, and the other end of the spring abuts against the inward concave ring of the oil piston.

[0019] Preferably, a through hole is arranged in the center of the oil piston, and one end of the slide valve rod passes through the through hole of the oil piston and is connected to the oil piston by screws.

[0020] Preferably, the loading solenoid valve and the unloading solenoid valve are connected in parallel and then communicated with the oil cylinder.

[0021] The utility model provides a single-stage two-stage screw compressor with the volume ratio slide valve regulating mechanism.

[0022] The utility model also provides an air-conditioning unit with the single-stage two-stage screw compressor.

[0023] The volume ratio slide valve regulating device provided by the utility model is mostly used to regulate the volume ratio Vi of the high-pressure stage of a single-stage two-stage screw compressor. By arranging a spring between the side of the oil piston and the cylinder head, and at the same time connecting the oil in the cylinder to the low-pressure stage of the single-stage two-stage screw compressor through a pipeline by means of an unloading solenoid valve. When needed, the loading solenoid valve can be opened to input pressure oil into the cylinder, and at the same time the unloading solenoid valve is closed, so as to reduce Vi of the high-pressure stage. And it can truly achieve the adjustment to the position of the minimum Vi (Vi is close to 1) under the condition of a small pressure ratio. When the compressor starts, Vi of the high-pressure stage is the minimum Vi, and unloading start can be realized. It effectively solves the problem of starting in the bad state of large Vi in the prior art. Connecting the unloading oil circuit to the low-pressure stage of the compressor makes the pressure difference at both ends of the slide valve larger during unloading, and the unloading is stable and reliable. The utility model can timely adjust the size of Vi of the high-pressure stage of the compressor according to needs, that is, it can be adjusted to the position of the minimum Vi under the condition of a small pressure ratio. After the compressor stops, it can also be automatically adjusted to the small Vi state for unloading start. At the same time, Vi of the high-pressure stage can also be stably and reliably increased. Thus, the matching of the compressor pressure ratio is effectively realized to improve the efficiency of the compressor.

[0024] The spring is arranged between the inner side of the cylinder head and the oil piston, and shaft sections with different diameters are arranged on the inner side surface of the cylinder head. An inner concave ring is arranged on the side surface of the oil piston. Then one end of the spring is sleeved on the shaft section of the cylinder head, and the other end of the spring abuts against the inner concave ring of the oil piston. Such an arrangement can ensure the stable installation of the spring and reliable operation. The shaft section of the cylinder head is made hollow, and through holes are arranged around the small-diameter shaft section, which can reduce the weight of the part and increase the amount of oil in the cylinder for lubrication and cooling. Description of the Drawings

[0025] Figure 1 is a schematic diagram of the working principle of an existing single-stage two-stage screw compressor;

[0026] Figure 2 is a cross-sectional view of the high-pressure stage part of an existing single-stage two-stage screw compressor;

[0027] Figure 3 is a schematic diagram of the working principle of the single-stage two-stage screw compressor provided by the utility model;

[0028] Figure 4 is a cross-sectional view of the high-pressure stage part of the single-stage two-stage screw compressor of the utility model;

[0029] Figure 5 is Figure 4 a three-dimensional view of the cylinder head in

[0030] Figure 6 is Figure 4 a three-dimensional view of the left side perspective of the oil piston in

[0031] Figure 7For Figure 4 A perspective view of the right side of the oil piston.

[0032] In the figure: 1 - suction port, 2 - first-stage compression screw rotor, 3 - second-stage compression screw rotor, 4 - spring, 5 - oil cylinder, 6 - oil piston, 61 - concave circular ring, 62 - through hole, 7 - exhaust port, 8 - slide valve, 9 - pipeline, 10 - motor, 11 - slide valve rod, 12 - oil cylinder cover, 121 - small-diameter shaft section, 122 - annular step. Specific embodiments

[0033] In order to make the objectives, technical solutions and advantages of the present utility model clearer, the present utility model will be described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the following specific embodiments are only used to explain the present utility model and do not constitute a limitation to the present utility model.

[0034] As Figure 3 、 Figure 4 shown, an embodiment of a single-stage two-stage screw compressor provided by the present utility model. The screw compressor includes a housing, a motor 10, a first-stage compression screw rotor 2, a second-stage compression screw rotor 3, and a volume ratio (Vi) slide valve regulating device for the high-pressure stage provided by the present utility model, which are sequentially arranged in the housing from right to left. The right side of the compressor is the suction port 1 of the first-stage compression screw rotor, that is, the low-pressure stage suction port, with a pressure of Ps; the middle pressure stage is between the first-stage compression screw rotor 2 and the second-stage compression screw rotor 3, with a pressure of Pm, which is the first-stage exhaust pressure and also the second-stage suction pressure; the end of the second-stage compression screw rotor 3 is the high-pressure stage, with a pressure of the second-stage exhaust pressure Pd, which is also the total exhaust pressure of the compressor, and the gas in the high-pressure stage is discharged through the exhaust port 7. The present utility model also provides an air-conditioning unit having the single-stage two-stage screw compressor.

[0035] As Figure 3 、 Figure 4 shown, the volume ratio slide valve regulating device for the high-pressure stage provided by the present utility model includes a slide valve 8 arranged on one side of the second-stage compression screw rotor 3 and a slide valve rod 11 fixed to the left end of the right end of the slide valve. The left end of the slide valve rod extends out of the compressor housing and is connected to the right side of the oil piston 6 in the oil cylinder 5. It also includes a loading solenoid valve V1 and an unloading solenoid valve V2 communicated with the oil cylinder. A spring 4 is arranged between the left side surface of the oil piston 6 and the oil cylinder body, that is, the spring is arranged in the inner cavity of the oil cylinder. Moreover, the unloading solenoid valve V2 communicates the oil cylinder 5 with the suction part of the low-pressure stage of the single-stage two-stage screw compressor. Pressure oil can be input into the oil cylinder through the loading solenoid valve V1, with an oil pressure of Po; the pressure oil in the oil cylinder can be input into the low-pressure stage in the compressor through the unloading solenoid valve V2.

[0036] As Figure 2 、 Figure 4As shown in the figure, the combined forces of the oil piston, the slide valve rod and the slide valve in the high-pressure stage volume ratio slide valve regulating device. That is, the loading and unloading forces of the slide valve are as follows:

[0037] When the compressor needs to be loaded to the minimum Vi (close to 1), the loading solenoid valve V1 is opened and the unloading solenoid valve V2 is closed. At this time, the oil cylinder pressure Po is approximately equal to the exhaust pressure Pd and also approximately equal to the medium pressure stage pressure Pm, that is, Po≈Pd≈Pm. Then the combined force of the oil piston, the sliding valve rod and the sliding valve is:

[0038] (Cylinder pressure Po x oil piston left pressure area S1) - (exhaust pressure Pd x oil piston right pressure area S2) + (exhaust pressure Pd x slide valve left pressure area S3) - (medium pressure stage pressure Pm x slide valve right pressure area S4) + spring force Fs - friction force Fn. S3≈S4, simplified, the comprehensive force of the slide valve can be obtained as: Pm(S1-S2)+Fs-Fn.

[0039] Then, we only need to ensure that the spring force Fs is greater than the friction force Fn (when the force is positive, the slide valve moves to the right), which can be easily verified by calculating the spring compression and field experiments. Therefore, Vi can be made smaller by loading.

[0040] In order to unload the compressor from small Vi to maximum Vi, the unloading solenoid valve V2 can be opened and the loading solenoid valve V2 can be closed. The oil in the oil cylinder quickly flows to the low-pressure stage through the pipeline 9, and the oil cylinder pressure Po is approximately equal to the low-pressure stage suction pressure Ps, that is, Po≈Ps. The combined force of the oil piston, the sliding valve rod and the sliding valve is:

[0041] (Medium pressure stage pressure Pm x pressure area S4 on the right side of the slide valve) - (cylinder pressure Po x pressure area S1 on the left side of the oil piston) + (exhaust pressure Pd x pressure area S2 on the right side of the oil piston) - (exhaust pressure Pd x pressure area S3 on the left side of the slide valve) - spring force Fs - friction force Fn), by simplifying, the force on the slide valve at this time can be roughly obtained as follows:

[0042] PmXS4-PoXS1-Fs-Fn.

[0043] Since Pm-Po (Ps) is the suction and exhaust pressure difference of the low-pressure stage, the force generated by the pressure difference at this time is greater than the friction force and the spring force, so the unloading can be completed, causing the slide valve to move to the left. That is, the unloading oil circuit is connected to the low-pressure stage of the compressor, so that the pressure difference at both ends of the slide valve is larger during unloading, so as to stably and reliably increase to the appropriate high-pressure stage Vi.

[0044] When the compressor stops, the suction and discharge pressures are balanced. At this time, the combined force acting on the oil piston, slide valve rod, and slide valve is the spring force Fs - the frictional force Fn. The designed spring force is greater than the frictional force, so the slide valve moves to the right and is pushed to the minimum Vi position. At this time, the high-pressure stage pressure ratio is very small, the power consumption is small, and it is in the unloaded starting state, which can avoid the problem of the motor stalling due to excessive current when starting with load.

[0045] However, for the existing slide valve adjustment mechanism as Figure 2 shown, when the compressor stops, the slide valve is affected by the spring force rebounding to the left and will move to the left and be pushed to the large Vi position. At this time, the high-pressure stage pressure ratio (the discharge volume is small, the discharge pressure Pd is large, that is, Pd / Pm is large) is large, the power consumption is large, and it is easy to have the problem of stalling due to excessive starting current. Obviously, it cannot work under the condition of small Vi either.

[0046] The utility model can timely adjust the size of the high-pressure stage Vi of the compressor according to needs, that is, it can be adjusted to the minimum Vi position under the condition of small pressure ratio. After the compressor stops, it can also be automatically adjusted to the small Vi state for unloaded starting. At the same time, it can also stably and reliably increase the Vi of the high-pressure stage. Thus, the matching of the compressor pressure ratio is effectively realized, and the efficiency of the compressor is improved.

[0047] As Figure 4 shown, the oil cylinder 5 of the utility model includes a cylinder block and an oil cylinder cover 12, and the spring 4 is arranged between the inner side of the oil cylinder cover 12 and the oil piston 6. As Figure 5 shown, two shaft sections with different diameters extend outward from the inner side surface of the oil cylinder cover, and an annular step 122 is formed between the large-diameter shaft section and the small-diameter shaft section 121. And the shaft section is hollow, and through holes are also provided around the small-diameter shaft section. As Figure 6 shown, the side surface of the oil piston 6 facing the oil cylinder cover is provided with an inwardly concave circular ring 61. Please combine Figure 4 . During installation, the left end of the spring 4 is sleeved on the small-diameter shaft section 121 of the oil cylinder cover, and the right end of the spring abuts against the inwardly concave circular ring 61 of the oil piston. As Figure 7 shown, a through hole 62 is provided in the center of the oil piston. During installation, the left end of the slide valve rod 11 passes through the through hole of the oil piston and is fixedly connected to the oil piston by screws.

[0048] By arranging the spring between the inner side of the oil cylinder cover and the oil piston, and also arranging shaft sections with different diameters on the inner side surface of the oil cylinder cover and an inwardly concave circular ring on the side surface of the oil piston, and then sleeving one end of the spring on the shaft section of the oil cylinder cover and the other end of the spring abutting against the inwardly concave circular ring of the oil piston. Such a setting can ensure the stable installation of the spring and reliable operation. Making the shaft section of the oil cylinder cover hollow and providing through holes around the small-diameter shaft section can reduce the weight of the parts and increase the amount of oil in the oil cylinder for lubrication and cooling. Using screws to fixedly connect the oil piston and the slide valve rod is convenient and reliable. As Figure 3As shown, the oil circuits provided with the loading solenoid valve V1 and the unloading solenoid valve V2 are connected in parallel and then connected to the oil cylinder 5. This makes it easy to process the oil circuit in the cylinder block and convenient for loading or unloading.

[0049] It should be noted that the terms used in this specification are only for describing specific embodiments and are not intended to limit the present invention. Unless otherwise specifically stated, the relative arrangements of the technical features and steps described in these embodiments, as well as the numerical expressions and values, do not limit the protection scope of the present invention.

[0050] For technologies, methods, and devices known to those of ordinary skill in the relevant fields, no detailed discussion is made in this specification, but where appropriate, the said technologies, methods, and devices should be regarded as part of this specification. Any specific value in this specification should be interpreted as merely exemplary and does not constitute a limitation to the present invention.

[0051] In order to facilitate description, the terms used in the specification to describe positions, such as "above...", "to the left of...", "in front of...", etc., are only used to describe the spatial position relationship between a certain component and other components in the embodiments shown in the drawings. When the position where the component is placed is different, the relative position will change. Therefore, the position relationship of the embodiments in the drawings should not constitute a limitation to the present invention.

[0052] In addition, it should be noted that the terms "first", "second", etc. used in the specification are only for distinguishing similar components and there is no sequence priority, so it cannot be understood as constituting a limitation to the protection scope of the present invention.

[0053] The above are only the specific embodiments of the present invention. It should be pointed out that any modifications, equivalent replacements, and changes made within the spirit and framework of the concept of the present invention should be included within the protection scope of the present invention.

[0054] ​

Claims

1. A volume ratio slide valve regulating device, comprising an oil cylinder and an oil piston, a slide valve rod and a slide valve connected in sequence to one side of the oil piston, a loading solenoid valve and an unloading solenoid valve connected to the oil cylinder, characterized in that: A spring is arranged between the other side of the oil piston and the oil cylinder, and the unloading solenoid valve connects the oil cylinder with the low-pressure stage of the single-unit two-stage screw compressor.

2. The volume ratio slide valve regulating device according to claim 1, characterized in that: The oil cylinder comprises a cylinder body and an oil cylinder cover, and the spring is arranged between the inner side of the oil cylinder cover and the oil piston.

3. The volume ratio slide valve regulating device according to claim 2, characterized in that: The inner side surface of the oil cylinder cover extends outwardly to form two shaft sections with different shaft diameters.

4. The volume ratio slide valve regulating device according to claim 2, characterized in that: The shaft section of the oil cylinder cover is hollow, and a through hole is arranged around the small diameter shaft section.

5. The volume ratio slide valve regulating device according to claim 1, characterized in that: A concave ring is provided on the side of the oil piston that abuts against the spring.

6. The volume ratio slide valve regulating device according to claim 2, characterized in that: One end of the spring is sleeved on the small radial shaft section of the oil cylinder cover, and the other end of the spring abuts against the concave circular ring of the oil piston.

7. The volume ratio slide valve regulating device according to claim 2, characterized in that: A through hole is provided at the center of the oil piston, and one end of the sliding valve rod passes through the through hole of the oil piston and is connected to the oil piston by a screw.

8. The volume ratio slide valve regulating device according to claim 1, characterized in that: The loading solenoid valve and the unloading solenoid valve are connected in parallel and communicated with the oil cylinder.

9. A single-unit two-stage screw compressor, characterized in that: It comprises a volume ratio slide valve regulating device as described in any one of claims 1 to 8.

10. An air conditioning unit, characterized in that: It comprises the single-unit two-stage screw compressor as claimed in claim 9.

Images