Screw compressor with adjustable internal volume ratio

Abstract

A screw compressor is provided having adjustable internal volume ratio, including a body and a male rotor, a female rotor and a slide valve configured inside the body, a groove being configured at one side of the male rotor and the female rotor, and the slide valve being configured inside the groove with the slide valve movable inside the groove from a first position corresponding to a minimum internal volume ratio to a second position corresponding to a maximum internal volume ratio.

Claims

1. A screw compressor having an adjustable internal volume ratio, wherein the screw compressor comprises: a body; a male rotor; a female rotor; a slide valve inside the body; and a groove being configured at one side of the male rotor and the female rotor, wherein the slide valve is configured inside the groove, wherein the slide valve is able to move inside the groove from a first position corresponding to a minimum internal volume ratio to a second position corresponding to a maximum internal volume ratio, wherein the slide valve comprises a first end disposed next to respective suction ends of the male rotor and the female rotor, and wherein in the second position, the first end of the slide valve is flush with the suction ends of the male rotor and the female rotor.

2. The screw compressor with the adjustable internal volume ratio according to claim 1, wherein the slide valve is able to move to a third position corresponding to a middle internal volume ratio, and wherein the third position is between the first position and the second position.

3. The screw compressor with the adjustable internal volume ratio according to claim 1, wherein the slide valve comprises a second end disposed next to respective exhaust ends of the male rotor and the female rotor, and a radial exhaust port being configured at the second end of the slide valve.

4. The screw compressor with the adjustable internal volume ratio according to claim 3, wherein in the first position the first end extends outside the suction ends, while the second end does not extend outside the exhaust ends, and wherein in the second position the slide valve is entirely wrapped between the female rotor and the male rotor.

5. The screw compressor with the adjustable internal volume ratio according to claim 3, wherein in the third position, the first end extends outside the suction ends.

6. The screw compressor with the adjustable internal volume ratio according to claim 1, wherein the slide valve is driven by high pressure oil.

7. The screw compressor with the adjustable internal volume ratio according to claim 6, wherein the screw compressor with adjustable internal volume ratio comprises a hydraulic cylinder with an adjusting piston connected to the slide valve, wherein the adjusting piston is configured inside the hydraulic cylinder.

8. The screw compressor with the adjustable internal volume ratio according to claim 7, wherein the hydraulic cylinder is connected to an oil pipeline, which is connected to a suction cavity of the screw compressor, an upload magnetic valve and an unload magnetic valve being configured on the oil pipeline, and a first adjusting opening and a second adjusting opening being configured on the hydraulic cylinder, with the first adjusting opening and the second adjusting opening being connected to the magnetic valves.

9. The screw compressor with the adjustable internal volume ratio according to claim 1, wherein the length of the slide valve is determined by a maximum internal volume ratio designed for the screw compressor.

10. A screw compressor having an adjustable internal volume ratio, wherein the screw compressor comprises: a body; a male rotor; a female rotor; a slide valve inside the body; and a groove being configured at one side of the male rotor and the female rotor, wherein the slide valve is configured inside the groove, wherein the slide valve is able to move inside the groove from a first position corresponding to a minimum internal volume ratio to a second position corresponding to a maximum internal volume ratio, wherein the slide valve comprises a first end disposed next to respective suction ends of the male rotor and the female rotor and a second end disposed next to respective exhaust ends of the male rotor and the female rotor, wherein in the first position, the first end of the slide valve is longitudinally extended beyond the suction ends of the male rotor and the female rotor, and wherein in the second position, the first end of the slide valve is flush with the suction ends of the male rotor and the female rotor.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a diagrammatic sketch of a slide valve of a compressor with fixed low internal volume ratio;

(2) FIG. 2. is a diagrammatic sketch of a slide valve of a compressor with fixed high internal volume ratio;

(3) FIG. 3 is a diagrammatic sketch of a slide valve of a compressor at low Vi position with adjustable internal volume ratio;

(4) FIG. 4 is a diagrammatic sketch of a slide valve of a compressor at high Vi position with adjustable internal volume ratio;

(5) FIG. 5 is diagrammatic sketch of a slide valve (first position) of a screw compressor with adjustable internal volume ratio of the present invention;

(6) FIG. 6 is diagrammatic sketch of a slide valve (second position) of a screw compressor with adjustable internal volume ratio of the present invention;

(7) FIG. 7 is diagrammatic sketch of a screw compressor with adjustable internal volume ratio of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

(8) In the descriptions of the following paragraphs, plenty of specific details are provided to enable in-depth understanding of the present invention. However, it is obvious for those skilled in art that the present invention is able to be implemented without one or more details of such. In other examples, to avoid confusion with the present invention, some technical features known to the public in this field are not described.

(9) In order to thoroughly understand the present invention, the detailed structures will be put forward in the following descriptions. It is obvious that the implementation of the embodiments of the present invention is not limited to the special details familiar to those skilled in art. Preferable embodiments of the present invention are detailed below. However, apart from such detailed descriptions, the present invention is able to have other embodiments.

(10) As shown in FIG. 5, the present invention discloses a screw compressor with adjustable internal volume ratio, comprising a body and a male rotor 1, a female rotor 2 and a slide valve 5 configured inside said body, a groove 8 being configured along axial of the male rotor 1 and the female rotor 2 and the groove 8 containing the slide valve 5, and the slide valve 5 is able to move inside the groove 8 from a first position to a second position, and the slide valve 5 provides changeable internal volume ratio and capacity to the screw compressor with adjustable internal volume ratio, and the length of the slide valve 5 is determined by a maximum internal volume ratio required by the screw compressor, and when the slide valve 5 is at the first position, internal volume ratio is minimum, while at the second position, internal volume ratio is maximum, and the slide valve is able to move to a third position between the first position and the second position to provide a middle internal volume ratio.

(11) The screw compressor with adjustable volume ratio of the present invention integrates the functions of an internal volume ratio adjusting block 4 (FIG. 3) and a slide valve 3 (FIG. 3) designed for a compressor with adjustable volume ratio, and is able to achieve adjustment of internal volume ratio and loads of the compressor so that the issues, like complicated structure, high creation costs and discontinous adjustment of loads caused by addition of a Vi adjusting block in the screw compressor with adjustable Vi are able to be solved.

(12) With the slide valve of the present invention, continuous adjustment of internal volume ratio and capacity of the screw compressor is achieved, and it becomes easy for control, comparative with fixed internal volume ratio screw compressor in terms of manufacture cost and satisfies the requirements of application of a screw compressor under multiple design working conditions. Under any working Vi, it is in a position to achieve continuous adjustment of capacity of the screw compressor, from 100% load to a minimum load, which is determined by the design of the compressor, and able to apply to all screw compressor adopting slide valve adjustment.

(13) Optionally, the rotor has a suction end and an exhaust end, specifically, the male rotor 1 has a male rotor suction end 11 and a male rotor exhaust end 12, while the female rotor 2 has a female rotor suction end 21 and a female rotor exhaust end 22. The slide valve has a first end 51 and a second end 52, the first end 51 next to the suction ends, and the second end 52 next to the exhaust ends. A radial exhaust port 59 is configured at the second end 52 of the slide valve.

(14) Optionally, as shown in FIG. 5, the first position is a position where the first end 51 extends outside the suction ends, and as shown in FIG. 6, the second position is a position where the first end 51 is level with the suction ends. In an optional embodiment, at the first position, a part of the slide valve 5 is outside the suction ends of the rotors, and at this moment, the section of the slide valve 5 extending outside does not function for wrapping the compression cavity of the male rotor 1 and female rotor 2. During the movement from the first position to the second position, as shown in FIG. 6, when the slide valve moves to the second position, the entire slide valve 5 functions for wrapping the compression cavity of the male rotor 1 and female rotor 2, and Vi reaches the maximum value. During the movement from the first position to the second position, the slide valve 5 moves towards the exhaust ends, and Vi of the screw compressor is increasing, and when the slide valve 5 arrives at the second position, Vi of the screw compressor reaches the maximum value.

(15) The region between the first position and the second position is an adjustable range of internal volume ratio: by adjusting the position of the slide valve 5, any internal volume ratio of the compressor between the minimum internal volume ratio and the maximum internal volume ratio is able to be achieved to satisfy various system Vi requirements.

(16) Optionally, where the first end of the slide valve 5 is ensured to be level with the suction ends of the female and male rotors, the length of the slide valve 5 is determined by the maximum of the internal volume ratio required by the screw compressor.

(17) Optionally, the slide valve is driven by high pressure oil.

(18) Further optionally, as shown in FIG. 7, the screw compressor with adjustable internal volume ratio comprises a suction cavity and a hydraulic cylinder 6 with an adjusting piston 63 connected to the slide valve being configured inside the hydraulic cylinder 6, and the hydraulic cylinder 6 is connected to an oil pipeline, which comprises an unload oil pipeline and an upload oil pipeline, with an unload magnetic valve 71 being configured on the unload oil pipeline and an upload magnetic valve 72 being configured on the upload oil pipeline, and a first adjusting opening 61 and a second adjusting opening 62 being configured on the hydraulic cylinder 6, with first adjusting opening 61 and said second adjusting opening being 62 connected to the magnetic valves. Additionally, as shown, the slide valve 5 is positioned in a third position 73 corresponding to a middle internal volume ratio between the first position shown in FIG. 5 and the second position shown in FIG. 6.

(19) In an optional embodiment of the present invention, when the unload magnetic valve 71 is opened, the slide valve 5 moves towards right direction (the upload magnetic valve 72 is closed at this moment), and when the upload magnetic valve 72 is opened, the slide valve 5 moves towards left direction (the unload magnetic valve 71 is closed at this moment), and the first adjusting opening 61 and the second adjusting opening 62 are adjusting openings for internal volume ratio, the exterior pipelines of which are connected to the suction cavity of the compressor with magnetic valves being configured on the pipelines to control switching.

(20) The screw compressor of the present invention realizes adjustment of internal volume ratio as follows:

(21) Minimum internal volume ratio: open the upload magnetic valve 72, and close the unload magnetic valve 71 as well as the magnetic valves on the connecting pipes of the first adjusting opening 61 and the second adjusting opening 62, and the screw compressor is uploaded to full-load, at this moment the slide valve 5 is at the left end and the compressor corresponds to the minimum internal volume ratio.

(22) Middle internal volume ratio: open the magnetic valve (without indication) connected to the second adjusting opening 62, and rest of the magnetic valves are closed, and the slide valve 5 moves towards right side until the second adjusting opening; at this moment, internal volume ratio of the compressor is between the maximum and minimum values of internal volume ratio; those skilled in art should know that the specific value of internal volume ratio at this position is able to be calculated by design of the position of the slide valve 5; in like manner, according to different positions of the second adjusting opening 62, different middle internal volume ratios are able to be obtained.

(23) Maximum internal volume ratio: open the magnetic valve (without indication) connected to the first adjusting opening 61, and rest of the magnetic valves are closed, and the slide valve 5 continues to move towards right side, when the slide valve 5 arrives at the first adjusting opening 61, the slide valve 5 entirely enters into the region of the rotors, and at this moment the compressor is at the second position so that the maximum internal volume ratio is obtained.

(24) With respect to compressor capacity adjustment, those skilled in art should understand that with combination control by the unload magnetic valve 71 and the upload magnetic valve 72, same as the existing design of the compressor with fixed internal volume ratio, adjustment of capacity of the compressor is able to be achieved.

(25) The screw compressor with adjustable internal volume ratio of the present invention, with the slide valve, continuous adjustment of internal volume ratio and capacity of the screw compressor is achieved, and it becomes easy for control, comparative with fixed internal volume ratio screw compressor in terms of manufacture cost, and satisfies the requirements of application of a screw compressor under multiple design working conditions, such as cooling condition and heating condition on heat pump unit.

(26) The present invention has been illustrated by aforesaid embodiments, but it should be understood that aforesaid embodiments are only for exampling and illustration rather than being intended to limit the present invention within the scope of the embodiments described. In addition, those skilled in art are in a position to understand that the present invention is not limited to aforesaid embodiments, and according to the instructions of the present invention, various variants and modifications are able to be obtained, and such variants and modifications fall into the scope claimed for protection of the present disclosure.