Dry oil-free screw compressor and control method thereof

Abstract

The present invention discloses a dry oil-free screw compressor and a control method thereof, wherein the dry oil-free screw compressor comprises at least two-stage screw compression assemblies and a condensate separation and distribution mechanism; the first screw compression assembly is a low-pressure screw compression assembly, the second screw compression assembly is a secondary-pressure screw compression assembly; the third screw compression assembly is a high-pressure screw compression assembly; the condensate separation and distribution mechanism is connected to the air outlet of the compressed air terminal cooler to separate the condensate in the compressed air; the condensate separation and distribution mechanism transports the separated condensate to the rotor chambers of the second and third screw compression assemblies, where it is cooled and sealed, and the excess condensate is discharged. The dry oil-free screw compressor and the control method thereof proposed by the present invention can reduce the exhaust temperature, reduce the leakage of compressed gas, and reduce the specific power.

Description

Technical Field

[0001] The invention belongs to the technical field of compression devices and relates to a screw compressor, in particular to a dry oil-free screw compressor and a control method thereof. Background Art

[0002] There are two methods for obtaining oil-free compressed air with existing screw compressors, namely water-lubricated oil-free screw compressors and dry oil-free screw compressors.

[0003] Water-lubricated oil-free screw compressors spray cooling water into the screw rotor cavity for cooling and density, which reduces the exhaust temperature and leakage of the unit and improves the performance of the unit; however, the cooling water is recycled, and cooling water used for a long time is prone to produce bacteria, affecting the quality of the air.

[0004] The screw rotor cavity of the dry oil-free screw compressor uses air for compression. After the interstage compressed air is cooled, the condensed water is separated by the air-water separator and then enters the next stage for compression. Existing dry oil-free screw compressors have the defects of high exhaust temperature and large leakage.

[0005] In view of this, there is an urgent need to design a new dry oil-free screw compressor so as to overcome at least part of the above-mentioned defects of the existing dry oil-free screw compressors. Summary of the invention

[0006] The invention provides a dry oil-free screw compressor and a control method thereof, which can lower the exhaust temperature, reduce the leakage of compressed gas and reduce the specific power.

[0007] To solve the above technical problem, according to one aspect of the present invention, the following technical solution is adopted:

[0008] A dry oil-free screw compressor, comprising at least three stages of screw compression components and a condensate separation and distribution mechanism;

[0009] At least three-stage screw compression assembly includes a low-pressure screw compression assembly, at least one primary pressure screw compression assembly and a high-pressure screw compression assembly;

[0010] The screw compression assemblies are connected in series in sequence, and the outlet of each screw compression assembly is connected to a cooler; the condensed water separation and distribution mechanism is respectively connected to the output end of each cooler to separate the condensed water in the compressed air output from the air outlet of each cooler;

[0011] The condensed water separation and distribution mechanism is connected to the rotor chambers of each secondary-pressure stage screw compression assembly and the high-pressure stage screw compression assembly, and the received condensed water is transported to the rotor chambers of each secondary-pressure stage screw compression assembly and the high-pressure stage screw compression assembly for cooling and sealing, and the excess condensed water is discharged; the condensed water generated by the compression and cooling of water molecules in the continuously inhaled air ensures that the cooling water used is clean.

[0012] As an embodiment of the present invention, an exhaust port adjustment mechanism is provided at the exhaust port of each secondary pressure stage screw compression assembly and the high pressure stage screw compression assembly, which can automatically adjust the size of the exhaust port to achieve a suitable compression ratio and avoid over-compression and under-compression.

[0013] As an embodiment of the present invention, the screw compression assembly is provided with a compressor body and a pair of screw rotors;

[0014] The exhaust port regulating mechanism comprises a valve body and an elastic mechanism, wherein the valve body is provided with two end faces of different areas; the valve body can move freely in the body;

[0015] The elastic mechanism is arranged in the body, and the valve body is at the front end under the elastic force of the elastic mechanism; at this time, the exhaust opening is the largest;

[0016] The small end face of the valve body is connected to the last closed screw groove; the large end face of the valve body is connected to the exhaust port of the main machine through the second pipeline, and the size of the exhaust port of the screw compression assembly can be adjusted through the pressure difference between the two chambers.

[0017] As an embodiment of the present invention, the rotors of the first screw compression assembly and the second screw compression assembly are provided with an anti-rust coating to reduce the probability of rust.

[0018] As an embodiment of the present invention, the condensed water separation and distribution mechanism is arranged outside the body of each screw compression assembly.

[0019] As an embodiment of the present invention, the dry oil-free screw compressor includes a three-stage screw compression assembly, and the dry oil-free screw compressor includes a first cooler, a second cooler and a third cooler;

[0020] The outlets of the low-pressure screw compression assembly, the secondary-pressure screw compression assembly and the high-pressure screw compression assembly are connected to the first cooler, the second cooler and the third cooler respectively;

[0021] The output end of the first cooler is connected to the secondary-pressure screw compression assembly, the output end of the second cooler is connected to the high-pressure screw compression assembly, and the output end of the third cooler is connected to the condensate separation and distribution mechanism.

[0022] As an embodiment of the present invention, the dry oil-free screw compressor further includes a filter, and the filter is arranged in the air inlet pipeline of the low-pressure stage screw compression assembly.

[0023] As an embodiment of the present invention, the condensed water separation and distribution mechanism includes a distribution mechanism cavity, and the distribution mechanism cavity is respectively provided with a distribution mechanism inlet, a distribution mechanism outlet, a liquid level switch interface, an automatic liquid filling port, and an automatic liquid drain port;

[0024] The inlet of the distribution mechanism is respectively connected to the first cooler, the second cooler and the third cooler, and the outlet of the distribution mechanism is respectively connected to each secondary pressure stage screw compression assembly and the high pressure stage screw compression assembly;

[0025] The liquid level switch interface is used to connect the liquid level switch, the automatic drain port is connected to the drain solenoid valve, the drain solenoid valve is usually in a closed state, and the drain solenoid valve is connected to the liquid level switch; when the liquid is full to the set position, the liquid level switch sends a signal to the drain solenoid valve to open it, so that the automatic drain port can drain water; the automatic liquid replenishment port is connected to the spray holes of each screw compression host, and water is sprayed into the screw compression host through the pressure difference.

[0026] According to another aspect of the present invention, the following technical solution is adopted: a control method of the above-mentioned dry oil-free screw compressor, the control method comprising:

[0027] The condensed water separation and distribution mechanism is connected to the air outlets of each cooler to separate the condensed water in the compressed air output from the air outlets of each cooler;

[0028] The condensed water separation and distribution mechanism is connected to the rotor chambers of each secondary-pressure stage screw compression assembly and the high-pressure stage screw compression assembly, and the received condensed water is transported to the rotor chambers of each secondary-pressure stage screw compression assembly and the high-pressure stage screw compression assembly for cooling and sealing, and the excess condensed water is discharged.

[0029] The beneficial effects of the present invention are as follows: the dry oil-free screw compressor and the control method thereof proposed in the present invention can lower the exhaust temperature, reduce the leakage of compressed gas, and reduce the specific power.

[0030] The present invention eliminates the inter-stage air-water separator, and guides a portion of the condensed water separated by the air-water separator at the exhaust port of the unit to the front rotor cavity for cooling and sealing through the condensed water separation and distribution mechanism, and the excess condensed water is directly discharged. The condensed water generated by the compression and cooling of water molecules in the continuously inhaled air ensures that the cooling water used in the system is clean.

[0031] The present invention can use specific rotor materials to reduce the probability of rusting, and spray a special coating on the rotor surface. In addition, a device that can automatically adjust the size of the exhaust port is added to the high-pressure stage main engine to achieve a suitable compression ratio and avoid over-compression and under-compression. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 The figure is a schematic diagram of the composition of a dry oil-free screw compressor in one embodiment of the present invention.

[0033] Figure 2 It is a structural schematic diagram of a condensed water separation and distribution mechanism in one embodiment of the present invention.

[0034] Figure 3 It is a structural schematic diagram of a condensed water separation and distribution mechanism in one embodiment of the present invention.

[0035] Figure 4 It is a structural schematic diagram of a condensed water separation and distribution mechanism in one embodiment of the present invention.

[0036] Figure 5 This is a schematic diagram of the structure of a slide valve provided in a screw compression assembly in one embodiment of the present invention. DETAILED DESCRIPTION

[0037] The preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0038] In order to further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention.

[0039] The description in this section is only for several typical embodiments, and the present invention is not limited to the scope of the embodiments. The same or similar prior art means and some technical features in the embodiments are mutually replaced within the scope of the present invention.

[0040] The description of the steps in each embodiment in the specification is only for the convenience of explanation, and the implementation method of the present application is not limited by the order of implementation of the steps.

[0041] The term “connection” in the specification includes both direct connection and indirect connection.

[0042] The present invention discloses a dry oil-free screw compressor. Figure 1 FIG. 1 is a schematic diagram of the composition of a dry oil-free screw compressor according to an embodiment of the present invention; Figure 1 The dry oil-free screw compressor includes at least three-stage screw compression components and a condensate separation and distribution mechanism 7; the at least three-stage screw compression components include a low-pressure screw compression component 1, at least one primary pressure screw compression component 2 and a high-pressure screw compression component 3.

[0043] Each screw compression assembly is connected in series in sequence, and the outlet of each screw compression assembly is connected to a cooler; the condensed water separation and distribution mechanism is respectively connected to the output end of each cooler to separate the condensed water in the compressed air output from the air outlet of each cooler. In one embodiment, the dry oil-free screw compressor includes a three-stage screw compression assembly, and the dry oil-free screw compressor includes a first cooler 4, a second cooler 5 and a third cooler 6; the outlets of the low-pressure screw compression assembly 1, the secondary-pressure screw compression assembly 2 and the high-pressure screw compression assembly 3 are respectively connected to the first cooler 4, the second cooler 5 and the third cooler 6; and the output end of the first cooler 4 is connected to the secondary-pressure screw compression assembly 2, the output end of the second cooler 5 is connected to the high-pressure screw compression assembly 3, and the output end of the third cooler 6 is connected to the condensed water separation and distribution mechanism 7. The condensed water separation and distribution mechanism 7 is arranged outside the body of each screw compression assembly.

[0044] The condensed water separation and distribution mechanism 7 is connected to the rotor chambers of each secondary-pressure stage screw compression assembly 2 and the high-pressure stage screw compression assembly 3, and the received condensed water is transported to the rotor chambers of each secondary-pressure stage screw compression assembly 2 and the high-pressure stage screw compression assembly 3 for cooling and sealing, and the excess condensed water is discharged; the condensed water generated by the compression and cooling of water molecules in the continuously inhaled air ensures that the cooling water used is clean.

[0045] Figures 2 to 4 This is a schematic diagram of the structure of the condensate separation and distribution mechanism in one embodiment of the present invention; please refer to Figures 2 to 4 In one embodiment of the present invention, the condensed water separation and distribution mechanism 7 includes a distribution mechanism cavity 71, and the distribution mechanism cavity 71 is respectively provided with a distribution mechanism inlet 72, a distribution mechanism outlet 73, a liquid level switch interface 74, an automatic liquid replenishment port 75, and an automatic liquid discharge port 76. The distribution mechanism inlet 72 is respectively connected to the first cooler 4, the second cooler 5, and the third cooler 6, and the distribution mechanism outlet 73 is respectively connected to each secondary pressure stage screw compression assembly 2 and the high pressure stage screw compression assembly 3.

[0046] The liquid level switch interface 74 is used to connect the liquid level switch, and the automatic liquid drain port 76 is connected to the drain solenoid valve, which is usually in a closed state and connected to the liquid level switch; when the liquid is full to the set position, the liquid level switch sends a signal to the drain solenoid valve to open, so that the automatic liquid drain port 76 can drain water. The automatic liquid filling port 75 is connected to the liquid spraying hole of each screw compressor main unit, and water is sprayed into the screw compressor main unit through the pressure difference.

[0047] In addition, a filter screen 77 and several sealing rings 78 may be provided in the condensed water separation and distribution mechanism 7. The filter screen 77 may be provided in an area close to the liquid level switch interface 74, the automatic liquid replenishment port 75, and the automatic liquid discharge port 76. The condensed water enters the area after being filtered by the filter screen; the filter screen 77 may be a 10-mesh wire mesh. The sealing ring 78 may be provided at the connection with other components.

[0048] Figure 5 This is a schematic diagram of the structure of a screw compression assembly with a slide valve in one embodiment of the present invention; please refer to Figure 5 In one embodiment of the present invention, an exhaust port adjusting mechanism 8 is provided at the exhaust ports of each secondary-pressure stage screw compression assembly 2 and the high-pressure stage screw compression assembly 3, which can automatically adjust the size of the exhaust port to achieve a suitable compression ratio and avoid over-compression and under-compression.

[0049] Each secondary-stage screw compression assembly 2 and high-stage screw compression assembly 3 may be provided with a compressor body 301 and a pair of screw rotors 302, 303. The exhaust port adjustment mechanism 8 includes a valve body 801 and an elastic mechanism 802, wherein the valve body 801 is provided with two end surfaces 803, 804 of different areas; and the valve body 801 is freely movable in the body 301.

[0050] The elastic mechanism 802 is arranged in the body 301, and the elastic mechanism 802 can be a spring; under the action of the spring force, the valve body 801 is at the front end; at this time, the exhaust orifice is the largest. The small end face of the valve body 801 is connected to the last closed screw groove; the large end face of the valve body 801 is connected to the exhaust port of the main machine 301 through the second pipeline, and the size of the exhaust port of the screw compression assembly can be adjusted through the pressure difference between the two chambers.

[0051] The dry oil-free screw compressor further comprises a filter 9, which is arranged on the air inlet pipeline of the low-pressure screw compression assembly 1. In addition, the rotor of each screw compression assembly is provided with an anti-rust coating to reduce the probability of rust.

[0052] The present invention further discloses a control method for the above-mentioned dry oil-free screw compressor, the control method comprising:

[0053] The condensed water separation and distribution mechanism is connected to the air outlets of each cooler to separate the condensed water in the compressed air output from the air outlets of each cooler;

[0054] The condensed water separation and distribution mechanism is connected to the rotor chambers of each secondary-pressure screw compression assembly and the high-pressure screw compression assembly, and the received condensed water is transported to the rotor chambers of each secondary-pressure screw compression assembly and the high-pressure screw compression assembly for cooling and sealing, and the excess condensed water is discharged. The present invention ensures that the cooling water used is clean by compressing and cooling the water molecules in the air continuously.

[0055] In summary, the dry oil-free screw compressor proposed by the present invention can lower the exhaust temperature and reduce the leakage of compressed gas.

[0056] The present invention eliminates the inter-stage air-water separator, and guides a portion of the condensed water separated by the air-water separator at the exhaust port of the unit to the front rotor cavity for cooling and sealing through a condensed water distributor, and the excess condensed water is directly discharged. The condensed water generated by the compression and cooling of water molecules in the continuously inhaled air ensures that the cooling water used in the system is clean.

[0057] The present invention can use specific rotor materials to reduce the probability of rusting, and spray a special coating on the rotor surface. In addition, a device that can automatically adjust the size of the exhaust port is added to the high-pressure stage main engine to achieve a suitable compression ratio and avoid over-compression and under-compression.

[0058] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0059] The description and application of the present invention here are illustrative, and it is not intended to limit the scope of the present invention to the above-mentioned embodiments. The effects or advantages involved in the embodiments may not be embodied in the embodiments due to interference from various factors, and the description of the effects or advantages is not used to limit the embodiments. The deformation and change of the embodiments disclosed here are possible, and the replacement of the embodiments and the various equivalent parts are well known to those of ordinary skill in the art. It should be clear to those skilled in the art that the present invention can be implemented in other forms, structures, arrangements, proportions, and with other components, materials and parts without departing from the spirit or essential features of the present invention. Other deformations and changes can be made to the embodiments disclosed here without departing from the scope and spirit of the present invention.

Claims

1. A dry oil-free screw compressor, characterized in that: The dry oil-free screw compressor comprises at least three-stage screw compression components and a condensate separation and distribution mechanism; At least three-stage screw compression assembly includes a low-pressure screw compression assembly, at least one primary pressure screw compression assembly and a high-pressure screw compression assembly; The screw compression assemblies are connected in series in sequence, and the outlet of each screw compression assembly is connected to a cooler; the condensed water separation and distribution mechanism is respectively connected to the output end of each cooler to separate the condensed water in the compressed air output from the air outlet of each cooler; The condensed water separation and distribution mechanism is connected to the rotor chambers of each secondary-pressure screw compression assembly and the high-pressure screw compression assembly, and the received condensed water is transported to the rotor chambers of each secondary-pressure screw compression assembly and the high-pressure screw compression assembly for cooling and sealing, and the excess condensed water is discharged; the condensed water generated by the compression and cooling of water molecules in the continuously inhaled air ensures that the cooling water used is clean; The exhaust ports of each secondary-stage screw compression assembly and the high-stage screw compression assembly are provided with exhaust port adjustment mechanisms, which can automatically adjust the size of the exhaust port to achieve a suitable compression ratio and avoid over-compression and under-compression; Each secondary-pressure screw compression assembly and high-pressure screw compression assembly is provided with a compressor body and a pair of screw rotors; The exhaust port regulating mechanism comprises a valve body and an elastic mechanism, wherein the valve body is provided with two end faces of different areas; the valve body can move freely in the body; The elastic mechanism is arranged in the body, and the valve body is at the front end under the elastic force of the elastic mechanism; at this time, the exhaust opening is the largest; The small end face of the valve body is connected to the last closed screw groove; the large end face of the valve body is connected to the exhaust port of the main engine through the second pipeline, and the size of the exhaust port of the screw compression assembly can be adjusted through the pressure difference between the two chambers; The dry oil-free screw compressor comprises a three-stage screw compression assembly, and the dry oil-free screw compressor comprises a first cooler, a second cooler and a third cooler; The outlets of the low-pressure screw compression assembly, the secondary-pressure screw compression assembly and the high-pressure screw compression assembly are connected to the first cooler, the second cooler and the third cooler respectively; The output end of the first cooler is connected to the secondary-pressure screw compression assembly, the output end of the second cooler is connected to the high-pressure screw compression assembly, and the output end of the third cooler is connected to the condensed water separation and distribution mechanism; The condensed water separation and distribution mechanism comprises a distribution mechanism cavity, and the distribution mechanism cavity is respectively provided with a distribution mechanism inlet, a distribution mechanism outlet, a liquid level switch interface, an automatic liquid filling port, and an automatic liquid drain port; The inlet of the distribution mechanism is respectively connected to the first cooler, the second cooler and the third cooler, and the outlet of the distribution mechanism is respectively connected to each secondary pressure stage screw compression assembly and the high pressure stage screw compression assembly; The liquid level switch interface is used to connect the liquid level switch, the automatic drain port is connected to the drain solenoid valve, the drain solenoid valve is usually in a closed state, and the drain solenoid valve is connected to the liquid level switch; when the liquid is full to the set position, the liquid level switch sends a signal to the drain solenoid valve to open it, so that the automatic drain port can drain water; the automatic liquid replenishment port is connected to the spray holes of each screw compression host, and water is sprayed into the screw compression host through the pressure difference.

2. The dry oil-free screw compressor according to claim 1, characterized in that: The rotors of each screw compression assembly are provided with a rust-proof coating.

3. The dry oil-free screw compressor according to claim 1, characterized in that: The condensed water separation and distribution mechanism is arranged outside the body of each screw compression assembly.

4. The dry oil-free screw compressor according to claim 1, characterized in that: The dry oil-free screw compressor further comprises a filter, which is arranged in the air inlet pipeline of the low-pressure stage screw compression assembly.

5. A control method for a dry oil-free screw compressor according to any one of claims 1 to 4, characterized in that: The control method comprises: The condensed water separation and distribution mechanism is connected to the air outlets of each cooler to separate the condensed water in the compressed air output from the air outlets of each cooler; The condensed water separation and distribution mechanism is connected to the rotor chambers of each secondary-pressure stage screw compression assembly and the high-pressure stage screw compression assembly, and the received condensed water is transported to the rotor chambers of each secondary-pressure stage screw compression assembly and the high-pressure stage screw compression assembly for cooling and sealing, and the excess condensed water is discharged.

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