Oil-free screw compressor and its intake valve

Abstract

The present invention discloses an oil-free screw compressor intake valve, comprising a valve cover, a valve body, a valve disc, a valve stem, an elastic mechanism, a valve seat, and a muffler; the valve body is connected to the valve seat, the valve seat is provided with an oil-free compressor exhaust chamber, and a connecting channel is provided between the muffler and the oil-free compressor exhaust chamber; the first end of the valve stem is connected to a valve disc capable of controlling the compressor suction flow rate, the second end of the valve stem is provided with a sealing mechanism, and the connection port of the valve stem is provided near the oil-free compressor exhaust chamber; the valve disc is provided near the valve cover and can be opened or closed under the drive of the valve stem; a hydraulic chamber is provided inside the valve body, and the sealing mechanism is provided in the hydraulic chamber; hydraulic oil can be injected into the hydraulic chamber and into the first side of the sealing mechanism; the elastic mechanism is provided on the second side of the sealing mechanism. The oil-free screw compressor intake valve proposed by the present invention can effectively reduce the volume of the oil-free screw compressor intake valve, simplify its structure, and improve the stability of the valve during operation.

Description

Technical Field

[0001] The present invention belongs to the technical field of compressors and relates to an air intake valve for a screw compressor, in particular to an oil-free screw compressor and an air intake valve thereof. Background Art

[0002] The function of the screw compressor's intake valve is to reduce the load of the compressor during the start-up and shutdown stages by controlling the opening and closing of the intake valve during the loading and unloading process of the compressor, thereby avoiding the impact on the power grid caused by the instantaneous high power of the motor during startup. The working process of its normally closed intake valve is to control the opening of the valve disc in the valve by external force acting on the valve disc, thereby achieving the purpose of controlling the compressor's intake flow. The valve disc must not experience surge, cavitation, etc. when working at any opening. For oil-free screw compressors, in addition to meeting the above-mentioned purposes, the more important factor is that no additional media (such as lubricating oil, etc.) can enter the compressor through the intake valve at any time.

[0003] To achieve this, the intake valves used in oil-free screw compressors typically feature a top-in, bottom-out structure. The valve disc, which controls the valve opening, reciprocates up and down along a vertical axis. This is typically controlled by an external force generated by pneumatic or hydraulic pressure, via a mechanical interlock. However, both of these drive methods currently available on the market for oil-free screw compressor intake valves have significant drawbacks.

[0004] For air pressure-driven intake valves, firstly, because it is difficult to seal the gas, the sealing system of the pneumatically driven intake valve is more complicated, and generally a combination of multiple seals is used to achieve the sealing effect; secondly, due to the compressibility of the gas, its loading and unloading are completed in an instant, so the force acting on the valve plate will change instantaneously, causing the valve plate to be subjected to instantaneous load when the valve is opened or closed, causing the valve plate to be subjected to a large impact and easily deforming the valve plate. In order to avoid this phenomenon, additional mechanical devices are required to offset the impact caused by the instantaneous change in air pressure. All of the above causes problems such as complex structure, increased wearing parts, complex control system, and increased cost of the normally closed air pressure-driven intake valve.

[0005] The hydraulically driven intake valves currently used on the market, with their discs reciprocating up and down along a vertical axis, are often separated from the interlocking mechanism that controls the valve opening to prevent hydraulic oil from entering the compressor through the stem connected to the disc. These are connected by a lever or other mechanical device, resulting in large size, heavy weight, complex structure, and increased cost.

[0006] In view of this, there is an urgent need to design a new oil-free screw compressor intake valve to overcome the above-mentioned defects of the existing intake valve. Summary of the Invention

[0007] The present invention provides an oil-free screw compressor and an intake valve thereof, which can effectively realize the control of the suction flow rate during the start-up and shutdown stages of the compressor. The valve plate controlling the intake valve, the hydraulic cylinder controlling the valve opening, and the unloading valve of the compressor exhaust chamber are combined through a shaft, which greatly reduces the volume of the oil-free screw compressor intake valve, simplifies its structure, and improves the stability of the valve during operation.

[0008] In order to solve the above technical problems, according to one aspect of the present invention, the following technical solution is adopted:

[0009] An oil-free screw compressor intake valve, comprising: a valve cover, a valve body, a valve plate, a valve stem, an elastic mechanism, a valve seat and a muffler;

[0010] The valve body is connected to the valve seat, the valve seat is provided with an oil-free compressor exhaust cavity, and the muffler and the oil-free compressor exhaust cavity are provided with a connecting channel;

[0011] The first end of the valve stem is connected to the valve plate capable of controlling the suction flow of the compressor, the second end of the valve stem is provided with a sealing mechanism, and the connection port of the valve stem is provided near the exhaust chamber of the oil-free compressor; the valve plate is provided near the valve cover and can be opened or closed under the drive of the valve stem;

[0012] A hydraulic chamber is provided inside the valve body, and the sealing mechanism is provided in the hydraulic chamber; hydraulic oil can be injected into the hydraulic chamber and into a first side of the sealing mechanism, causing the sealing mechanism to move in a first direction, thereby separating the valve plate from the valve cover and sealing the connection port of the valve stem to block the connection passage provided between the muffler and the exhaust chamber of the oil-free compressor;

[0013] The elastic mechanism is provided on the second side of the sealing mechanism, and when the hydraulic oil is discharged from the hydraulic chamber, the sealing mechanism moves toward the second direction, the valve plate gradually closes and fits with the valve cover, the connecting port moves toward the second direction, and the exhaust chamber of the oil-free compressor is connected to the muffler.

[0014] As an embodiment of the present invention, the hydraulic chamber is provided with an oil filling port, through which hydraulic oil can be injected.

[0015] As an embodiment of the present invention, the elastic mechanism is a spring.

[0016] As an embodiment of the present invention, when the valve plate is in contact with the valve cover, the exhaust chamber of the oil-free compressor is connected to the exhaust muffler; when the valve plate is in the maximum open state, the exhaust chamber of the oil-free compressor is disconnected from the muffler.

[0017] An oil-free screw compressor comprises the above-mentioned oil-free screw compressor air inlet valve.

[0018] The beneficial effects of the present invention are as follows: the oil-free screw compressor and its intake valve proposed in the present invention can effectively realize the control of the suction flow rate during the start-up and shutdown stages of the compressor, and the valve plate that controls the intake valve, the hydraulic cylinder that controls the valve opening, and the unloading valve of the compressor exhaust chamber are combined through an axis, which greatly reduces the volume of the oil-free screw compressor intake valve, simplifies its structure, and improves the stability of the valve during operation.

[0019] First, the intake valve is hydraulically driven. Due to the incompressibility of liquid, the movement of the valve stem is gradual during the opening and closing of the valve. This makes the intake valve very stable during operation, without noise caused by short, violent impacts. Second, one end of the valve stem is connected to the valve plate that controls the compressor's intake air flow, and the other end is provided with a sealing structure, and the connection port is connected to the exhaust chamber of the oil-free compressor. This structure cleverly combines the state of the intake port and the state of the exhaust chamber when the compressor is running. When the compressor is running, the intake port is open and the exhaust chamber emptying channel is disconnected. When the compressor is stopped, the intake port is closed and the exhaust chamber emptying channel is opened. This greatly reduces the size of the intake valve, simplifies the structure, reduces additional control logic, and reduces costs. Finally, the valve stem makes reciprocating motion and forms a space with the valve body to set a hydraulic cylinder as the drive device for the valve operation. No additional hydraulic cylinder is required through mechanical interlocking, which simplifies the intake valve structure and improves stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 1 is a perspective view of an oil-free screw compressor intake valve according to an embodiment of the present invention.

[0021] Figure 2 Another perspective view of the intake valve of an oil-free screw compressor according to one embodiment of the present invention.

[0022] Figure 3 Schematic diagram of the structure of an oil-free screw compressor intake valve in one embodiment of the present invention.

[0023] Figure 4 This is a three-dimensional diagram of an oil-free screw compressor intake valve according to one embodiment of the present invention. DETAILED DESCRIPTION

[0024] The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0025] 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.

[0026] The description in this section is only for several typical embodiments, and the present invention is not limited to the scope of the embodiments described. The same or similar existing technical means and some technical features of the embodiments are mutually replaced within the scope of the description and protection of the present invention.

[0027] The present invention discloses an oil-free screw compressor intake valve, please refer to Figure 1 The intake valve includes: a valve cover 1, a valve body 3, a valve plate 2, a valve stem 4, an elastic mechanism 5, a valve seat 6 and a muffler 7; the valve body 3 is connected to the valve seat 6, the valve seat 6 is provided with an oil-free compressor exhaust chamber 9, and the muffler 7 and the oil-free compressor exhaust chamber 9 are provided with a connecting channel.

[0028] The first end of the valve stem 4 is connected to the valve plate 2 which can control the suction flow of the compressor. The second end of the valve stem 4 is provided with a sealing mechanism 41. The connection port 42 of the valve stem 4 is provided close to the exhaust chamber 9 of the oil-free compressor. The valve plate 2 is provided close to the valve cover 1 and can be opened or closed under the drive of the valve stem 4.

[0029] The valve body 3 is provided with a hydraulic chamber 8, and the sealing mechanism 41 is provided in the hydraulic chamber 8; hydraulic oil can be injected into the hydraulic chamber 8 and the first side of the sealing mechanism 41, so that the sealing mechanism 41 moves toward the first direction (such as Figure 1 The valve plate 2 is separated from the valve cover 1, and the connection port 42 of the valve stem 4 blocks the connection passage between the muffler 7 and the oil-free compressor exhaust chamber 9. In one embodiment of the present invention, the hydraulic chamber 8 is provided with an oil filling port through which hydraulic oil can be injected.

[0030] The second side of the sealing mechanism 41 is provided with the elastic mechanism 5, which can move the sealing mechanism 41 toward the second direction (such as Figure 2 When the valve plate 2 gradually closes and engages the valve cover 1, the connecting port 42 simultaneously moves in the second direction, connecting the oil-free compressor exhaust chamber 9 to the muffler 7. In one embodiment, the elastic mechanism 5 is a spring, and the hydraulic chamber 8 and the spring jointly control the operation of the intake valve's moving components. Of course, the elastic mechanism 5 may also have other structures, or even other reset mechanisms with reset functions.

[0031] The working principle of the present invention is as follows: before the oil-free screw compressor is started, there is no hydraulic oil in the hydraulic cylinder, and the valve stem 3, under the action of the spring force, pushes the valve plate connected to the valve stem to stick to the valve cover and seal it. At this time, the air inlet valve is in a closed state (see Figure 1 After the oil-free screw compressor is started, hydraulic oil is injected into the hydraulic cylinder. By controlling the pressure of the hydraulic oil, the valve stem is driven to move in the opposite direction, the intake valve disc is separated from the valve cover, and the intake valve disc opens and gradually reaches the maximum opening state (see Figure 2 When the oil-free screw compressor stops, the hydraulic oil is controlled to be discharged from the hydraulic chamber, the valve stem moves under the action of the spring force, and the valve plate gradually closes. At this time, the exhaust chamber of the oil-free compressor is connected to the exhaust muffler (see Figure 1 ), the high-pressure air in the exhaust chamber of the oil-free screw compressor is discharged through the exhaust muffler.

[0032] The present invention also discloses an oil-free screw compressor, comprising the above-mentioned oil-free screw compressor intake valve.

[0033] To sum up, the oil-free screw compressor and its intake valve proposed in the present invention can effectively realize the control of the suction flow rate during the start-up and shutdown stages of the compressor. The valve plate that controls the intake valve, the hydraulic cylinder that controls the valve opening, and the unloading valve of the compressor exhaust chamber are combined through an axis, which greatly reduces the volume of the oil-free screw compressor intake valve, simplifies its structure, and improves the stability of the valve during operation.

[0034] First, the intake valve is hydraulically driven. Due to the incompressibility of liquid, the movement of the valve stem is gradual during the opening and closing of the valve. This makes the intake valve very stable during operation, without noise caused by short, violent impacts. Second, one end of the valve stem is connected to the valve plate that controls the compressor's intake air flow, and the other end is provided with a sealing structure, and the connection port is connected to the exhaust chamber of the oil-free compressor. This structure cleverly combines the state of the intake port and the state of the exhaust chamber when the compressor is running. When the compressor is running, the intake port is open and the exhaust chamber emptying channel is disconnected. When the compressor is stopped, the intake port is closed and the exhaust chamber emptying channel is opened. This greatly reduces the size of the intake valve, simplifies the structure, reduces additional control logic, and reduces costs. Finally, the valve stem makes reciprocating motion and forms a space with the valve body to set a hydraulic cylinder as the drive device for the valve operation. No additional hydraulic cylinder is required through mechanical interlocking, which simplifies the intake valve structure and improves stability.

[0035] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned 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.

[0036] The description and application of the present invention here are illustrative and are not intended to limit the scope of the present invention to the above-described embodiments. The deformation and changes of the embodiments disclosed here are possible, and the replacement of the embodiments and the various components that are equivalent 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 realized in other forms, structures, arrangements, proportions, and with other components, materials and parts without departing from the spirit or essential characteristics of the present invention. Other deformation and changes can be made to the embodiments disclosed here without departing from the scope and spirit of the present invention.

Claims

1. An oil-free screw compressor intake valve, characterized in that: The air intake valve comprises: a valve cover, a valve body, a valve plate, a valve stem, an elastic mechanism, a valve seat and a muffler; The valve body is connected to the valve seat, the valve seat is provided with an oil-free compressor exhaust cavity, and the muffler and the oil-free compressor exhaust cavity are provided with a connecting channel; The first end of the valve stem is connected to the valve plate capable of controlling the suction flow of the compressor, the second end of the valve stem is provided with a sealing mechanism, and the connection port of the valve stem is provided near the exhaust chamber of the oil-free compressor; the valve plate is provided near the valve cover and can be opened or closed under the drive of the valve stem; A hydraulic chamber is provided inside the valve body, and the sealing mechanism is provided in the hydraulic chamber; hydraulic oil can be injected into the hydraulic chamber and into a first side of the sealing mechanism, causing the sealing mechanism to move in a first direction, thereby separating the valve plate from the valve cover and sealing the connection port of the valve stem to block the connection passage provided between the muffler and the exhaust chamber of the oil-free compressor; The elastic mechanism is provided on the second side of the sealing mechanism, and when the hydraulic oil is discharged from the hydraulic chamber, the sealing mechanism moves toward the second direction, the valve plate gradually closes and fits with the valve cover, and the connecting port moves toward the second direction, so that the exhaust chamber of the oil-free compressor is connected to the muffler; Before the oil-free screw compressor is started, there is no hydraulic oil in the hydraulic cylinder. The valve stem pushes the valve plate connected to the valve stem to stick to the valve cover and seal under the action of the elastic force of the elastic mechanism. At this time, the intake valve is in a closed state. After the oil-free screw compressor is started, hydraulic oil is injected into the hydraulic cylinder. By controlling the pressure of the hydraulic oil, the valve stem is driven to move in the opposite direction, the intake valve disc is separated from the valve cover, and the intake valve disc opens and gradually reaches the maximum opening state; When the oil-free screw compressor stops, the hydraulic oil is controlled to discharge from the hydraulic chamber, the valve stem moves under the action of the spring force, and the valve plate gradually closes. At this time, the exhaust chamber of the oil-free compressor is connected to the muffler, and the high-pressure air in the exhaust chamber of the oil-free screw compressor is discharged through the exhaust muffler.

2. The oil-free screw compressor intake valve according to claim 1, characterized in that: The hydraulic chamber is provided with an oil filling port, through which hydraulic oil can be injected.

3. The oil-free screw compressor intake valve according to claim 1, characterized in that: The elastic mechanism is a spring.

4. The oil-free screw compressor intake valve according to claim 1, characterized in that: When the valve plate is in contact with the valve cover, the exhaust chamber of the oil-free compressor is connected to the exhaust muffler; when the valve plate is in the maximum open state, the exhaust chamber of the oil-free compressor is disconnected from the muffler.

5. An oil-free screw compressor, characterized in that: The invention comprises the oil-free screw compressor intake valve according to any one of claims 1 to 4.

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