A pilot-operated open-loop controlled proportional flow valve

Abstract

The present invention relates to a pilot-operated open-loop control proportional flow valve, comprising a pilot valve and a main valve connected to each other, wherein the pilot valve comprises a controller and a pilot valve module; the main valve comprises a valve body, a valve core, a left end cover, a right end cover and a spring; the pilot valve control port of the pilot valve is connected to the main valve control port of the main valve, and the main valve control port of the main valve is connected to the right control chamber of the main valve; the pressure of the pilot valve control port of the pilot valve is in a first nonlinear characteristic relationship with the input signal, the pressure of the main valve control port of the main valve is in a linear relationship with the valve port opening of the main valve, and the valve port opening of the main valve is in a second nonlinear characteristic relationship with the output gas flow; through laboratory testing, the output gas flow and the input signal are corrected to form a linear relationship, and the pressure value of the intermediate variable pilot valve control port is solidified into the controller. Its advantages are: reasonable structure, suitable for gas flow control, and accurate control.

Description

Technical Field

[0001] The invention relates to the technical field of gas flow control, and in particular to a pilot-operated open-loop controlled proportional flow valve. Background Art

[0002] The flow rate of fluid (gas and liquid), when external conditions (pressure and temperature, etc.) remain unchanged, is generally related to the size of the cross-section of the space through which the fluid flows. For a specific flow valve, it is to control the opening of the valve port to achieve the output of the required flow value.

[0003] The so-called proportional flow valve means that the flow output of a control valve is linearly related to the input signal value (current or voltage) applied to it. The so-called pilot control valve means that the movement of the valve core of the main valve is controlled by the output pressure of the pilot valve.

[0004] The pilot valve is generally a miniature direct-acting proportional pressure valve. The direct-acting proportional pressure valve is generally composed of a control circuit, an electromechanical converter, and a control valve core. Its control mechanism is that the input electrical signal (voltage / current) is input into the control circuit, and after the signal is amplified, it is input into the electromechanical converter to output mechanical displacement. This displacement forms a valve opening to control the output pressure value. This pressure value is generally designed to be proportional to the input electrical signal.

[0005] The control pressure of the pilot valve is introduced into the control chamber of the main valve to control the movement of the main valve core. Through the valve core spring system, the valve core outputs a displacement (valve opening) that is linearly related to the pressure.

[0006] For liquid, within a certain flow range, the valve opening and flow rate can be approximately considered as a proportional relationship. Therefore, it has been widely used in the field of hydraulic control with good results.

[0007] However, due to the great difference between the physical properties of gas and liquid, liquid is generally considered to be an incompressible fluid, while gas is obviously a compressible fluid. The flow rate of gas flowing through the valve port is nonlinearly related to the opening of the valve port. In this way, the flow rate of gas cannot be proportional to the input signal.

[0008] With the in-depth development of Industry 4.0 technology, pneumatic technology, known as the muscle of industrial automation, has also changed. Pneumatic proportional technology has begun to enter the field of pneumatic control to meet the requirements of the flexible and programmable state of the control object in this era of Industry 4.0. The pilot-operated open-loop control proportional flow valve is a new product designed for this requirement. Summary of the invention

[0009] The technical problem to be solved by the present invention is to provide a pilot-operated open-loop control proportional flow valve with reasonable structure, applicable to gas flow control and accurate control in view of the current status of the prior art.

[0010] The technical solution adopted by the present invention to solve the above technical problems is:

[0011] A pilot-operated open-loop controlled proportional flow valve comprises a pilot valve and a main valve which are connected to each other. The pilot valve is provided with a pilot valve air inlet, a pilot valve pressure relief port and a pilot valve control port. The pilot valve comprises a controller and a pilot valve module. The main valve is provided with a main valve air supply port, a main valve exhaust port, a main valve control port, a working port and a pilot valve interface. The main valve comprises a valve body, a valve core, a left end cover, a right end cover and a spring. The spring is arranged between the valve core and the left end cover. The pilot valve control port of the pilot valve is connected to the main valve control port of the main valve. The main valve control port of the main valve is connected to the right control chamber of the main valve.

[0012] There is a first nonlinear characteristic relationship between the pressure at the pilot valve control port of the pilot valve and the input signal, a linear relationship between the pressure at the main valve control port of the main valve and the valve port opening of the main valve, and a second nonlinear characteristic relationship between the valve port opening of the main valve and the output gas flow rate; through laboratory tests, the output gas flow rate and the input signal are corrected to form a linear relationship, and the pressure value of the intermediate variable pilot valve control port is solidified into the controller.

[0013] The optimized technical measures also include:

[0014] The above-mentioned pilot valve module includes an intake solenoid valve, an exhaust solenoid valve, a pressure sensor and an air circuit base plate. The controller is connected to the intake solenoid valve and the exhaust solenoid valve. The pressure sensor is feedback connected to the controller. The intake solenoid valve is arranged between the air inlet of the pilot valve and the control port of the pilot valve, and the exhaust solenoid valve is arranged between the pressure relief port of the pilot valve and the control port of the pilot valve.

[0015] The controller includes a processor, an M / A analog-to-digital converter, an input / output interface circuit, a display circuit, a power supply and a solenoid valve driving circuit.

[0016] The left end of the above-mentioned right end cover is provided with a protrusion, and a right control chamber is formed between the outer periphery of the protrusion and the inner wall of the valve body.

[0017] A groove is arranged in the middle of the valve core.

[0018] A sealing ring is arranged between the right end cover and the valve body.

[0019] The above-mentioned right end cover is fixed to the valve body by screws.

[0020] An outer cover is arranged outside the controller and the pilot valve module.

[0021] A pilot-operated open-loop controlled proportional flow valve of the present invention has a reasonable structure and is composed of a pilot valve and a main valve. The pressure of the pilot valve control port of the pilot valve and the input signal present a first nonlinear characteristic relationship, the pressure of the main valve control port of the main valve and the valve port opening of the main valve present a linear relationship, and the valve port opening of the main valve presents a second nonlinear characteristic relationship with the output gas flow rate. Through laboratory testing, the output gas flow rate and the input signal are corrected to form a linear relationship, and the pressure value of the intermediate variable pilot valve control port is solidified into a controller. In this way, a linear relationship between the main valve flow rate and the input signal is achieved, and proportional control of the flow rate is achieved. The valve valve is suitable for a gas flow environment and can accurately control the flow rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the structure of the present invention;

[0023] Figure 2 yes Figure 1 Schematic diagram of the structure of the middle pilot valve without the outer cover;

[0024] Figure 3 yes Figure 1 Bottom view of the middle pilot valve;

[0025] Figure 4 It is the control principle diagram of the pilot valve of the present invention;

[0026] Figure 5 yes Figure 4 The structural diagram of the controller;

[0027] Figure 6 It is a structural schematic diagram of the main valve of the present invention;

[0028] Figure 7 is a top view of the main valve of the present invention;

[0029] Figure 8 It is a control principle diagram of the proportional flow valve of the present invention. DETAILED DESCRIPTION

[0030] The present invention is further described in detail below with reference to the accompanying drawings.

[0031] like Figures 1 to 8 Shown is a schematic diagram of the structure of the present invention,

[0032] The accompanying drawings are marked as follows: a first nonlinear characteristic relationship L1, a linear relationship L2, a second nonlinear characteristic relationship L3, a pilot valve air inlet P1, a pilot valve pressure relief port R1, a pilot valve control port K1, a main valve air supply port P2, a main valve exhaust port R2, a main valve control port K2, a working port A, a pilot valve 1, a controller 11, a processor 11a, an M / A analog-to-digital converter 11b, an input / output interface circuit 11c, a display circuit 11d, a power supply 11e, a solenoid valve drive circuit 11f, a pilot valve module 12, an intake solenoid valve 12a, an exhaust solenoid valve 12b, a pressure sensor 12c, an air path bottom plate 12d, an outer cover shell 13, a main valve 2, a pilot valve interface 2a, a right control chamber 2b, a valve body 21, a valve core 22, a groove 22a, a left end cover 23, a right end cover 24, a bump 24a, a spring 25, a sealing ring 26, and a screw 27.

[0033] like Figures 1 to 8 As shown,

[0034] A pilot-operated open-loop controlled proportional flow valve comprises a pilot valve 1 and a main valve 2 which are connected to each other. The pilot valve 1 is provided with a pilot valve air inlet P1, a pilot valve pressure relief port R1 and a pilot valve control port K1. The pilot valve 1 comprises a controller 11 and a pilot valve module 12. The main valve 2 is provided with a main valve air supply port P2, a main valve exhaust port R2, a main valve control port K2, a working port A and a pilot valve interface 2a. The main valve 2 comprises a valve body 21, a valve core 22, a left end cover 23, a right end cover 24 and a spring 25. The spring 25 is arranged between the valve core 22 and the left end cover 23. The pilot valve control port K1 of the pilot valve 1 is connected to the main valve control port K2 of the main valve 2. The main valve control port K2 of the main valve 2 is connected to the right control chamber 2b of the main valve 2.

[0035] There is a first nonlinear characteristic relationship L1 between the pressure of the pilot valve control port K1 of the pilot valve 1 and the input signal, a linear relationship L2 between the pressure of the main valve control port K2 of the main valve 2 and the valve port opening of the main valve 2, and a second nonlinear characteristic relationship L3 between the valve port opening of the main valve 2 and the output gas flow rate; through laboratory tests, the output gas flow rate and the input signal are corrected to form a linear relationship, and the pressure value of the intermediate variable pilot valve control port K1 is solidified into the controller 11.

[0036] In the embodiment, the pilot valve module 12 includes an intake solenoid valve 12a, an exhaust solenoid valve 12b, a pressure sensor 12c and an air circuit base plate 12d, the controller 11 is controlled and connected with the intake solenoid valve 12a and the exhaust solenoid valve 12b, the pressure sensor 12c is feedback-connected to the controller 11, the intake solenoid valve 12a is arranged between the pilot valve intake port P1 and the pilot valve control port K1, and the exhaust solenoid valve 12b is arranged between the pilot valve pressure relief port R1 and the pilot valve control port K1.

[0037] In the embodiment, the controller 11 includes a processor 11a, an M / A analog-to-digital converter 11b, an input / output interface circuit 11c, a display circuit 11d, a power supply 11e and a solenoid valve driving circuit 11f.

[0038] In the embodiment, a protrusion 24 a is disposed at the left end of the right end cover 24 , and a right control chamber 2 b is formed between the outer periphery of the protrusion 24 a and the inner wall of the valve body 21 .

[0039] In the embodiment, a groove 22a is provided in the middle of the valve core 22. The groove 22a is located at the main valve air supply port P2.

[0040] In the embodiment, a sealing ring 26 is provided between the right end cover 24 and the valve body 21 .

[0041] In the embodiment, the right end cover 24 is fixed to the valve body 21 by screws 27 .

[0042] In the embodiment, an outer cover 13 is disposed outside the controller 11 and the pilot valve module 12 .

[0043] Working principle:

[0044] The pilot-operated open-loop control proportional flow valve is composed of a connected pilot valve 1 and a main valve 2. The pilot valve 1 is provided with a pilot valve air inlet P1, a pilot valve pressure relief port R1 and a pilot valve control port K1. The main valve 2 is provided with a main valve air supply port P2, a main valve exhaust port R2, a main valve control port K2, a working port A and a pilot valve interface 2a. The three ports of the pilot valve interface 2a (see Figure 7 ) is connected to the pilot valve air inlet P1, the pilot valve pressure relief port R1 and the pilot valve control port K1 on the pilot valve 1. The pilot valve control port K1 is connected to the main valve control port K2, that is, the pressure of the pilot valve control port K1 is the same as that of the main valve control port K2.

[0045] like Figure 4As shown, the input signal sets the output pressure value of the pilot valve 1, and the pressure sensor 12c detects the actual pressure output by the pilot valve and feeds it back to the controller 11. After logical operation, the controller 11 sends an operation instruction to the solenoid valve (intake solenoid valve 12a, exhaust solenoid valve 12b): when the feedback pressure is greater than the set pressure, the intake solenoid valve 12a is closed, the exhaust solenoid valve 12b is opened, and the gas in the pilot valve control port K1 is exhausted to the outside through the exhaust solenoid valve 12b and the pilot valve pressure relief port R1, and the pressure of the pilot valve control port K1 decreases; conversely, when the feedback pressure is less than the set pressure, the intake solenoid valve 12a is opened, the exhaust solenoid valve 12b is closed, and the pilot valve intake port P1 supplies gas to the pilot valve control port K1 through the intake solenoid valve 12a, and the pressure of the pilot valve control port K1 increases. When the feedback pressure is equal to the set pressure, the intake solenoid valve 12a and the exhaust solenoid valve 12b are closed. At this time, the pressure of the pilot valve control port K1 is dynamically stabilized within the accuracy range allowed by the set pressure, thus establishing a correlation between the pressure of the pilot valve control port K1 and the input signal. The pressure of the pilot valve control port K1 and the input signal present a first nonlinear characteristic relationship L1.

[0046] like Figure 6 As shown, the pilot valve control port K1 of the pilot valve 1 is connected to the main valve control port K2 of the main valve 2, and the pressures of the two are equal. The main valve control port K2 is connected to the right control chamber 2b of the main valve 2, and the pressure of the right control chamber 2b is used to control the movement of the valve core 22 of the main valve 2. The force exerted by the pressure of the right control chamber 2b on the valve core 22 is balanced with the spring force at the left end of the valve core 22, so that the valve core 22 stays in a certain position, thereby controlling the opening of the valve port and controlling the gas flow. For a certain pressure of the main valve control port K2, a stable valve port opening will be obtained, and a stable gas flow can be obtained. In this way, a relationship is established between the pressure of the main valve control port K2 and the gas flow of the main valve. As shown in FIG. Figure 8 As shown, in the main valve 2, there is a linear relationship L2 between the elastic force of the spring 25 and the compression amount of the spring, but due to the gas characteristics, there is a nonlinear relationship between the opening of the valve port and the gas flow rate, that is, there is a second nonlinear characteristic relationship L3 between the opening of the valve port and the gas flow rate. That is to say, in the main valve 2, there is a nonlinear relationship between the pressure of the main valve control port K2 of the main valve 2 and the flow rate of the main valve 2.

[0047] By introducing the intermediate variable - the pressure of the control port, the relationship between the output gas flow of the main valve 2 and the input signal is established. Through laboratory testing, the relationship between the main valve flow and the input signal is corrected to a linear relationship, and the corresponding intermediate variable - the output control pressure value of the pilot valve is solidified into the controller; in this way, proportional control of the gas flow is achieved.

[0048] like Figure 8 The control principle of this proportional flow valve is shown below:

[0049] The input signal I is input to the controller 11 of the pilot valve 1 to set the output pressure value of the pilot valve 1. In the pilot valve 1, a specific functional relationship (i.e., the first nonlinear characteristic relationship L1) is established between the input signal I and the output variable P (control port pressure). The output variable P of the pilot valve 1 serves as the input variable P' of the main valve 2. In the main valve 2, the input variable P' outputs a variable, i.e., the displacement X of the valve core 22, through the spring system. The displacement X of the valve core 22 is linearly related to the input variable P' (i.e., the linear relationship L2). The displacement X of the valve core 22 corresponds to the opening of the valve port, and there is a functional relationship between the opening of the valve port and the output flow Q (i.e., the second nonlinear characteristic relationship L3). The functional relationship between the opening of the valve port and the output flow Q is inherent in the valve structure itself, and there is a nonlinear relationship between them. The specific value of the functional relationship can be obtained by testing in the laboratory.

[0050] The above establishes the relationship from the input signal I to the output flow Q. The entire relationship chain contains two sets of nonlinear relationships (the first nonlinear characteristic relationship L1 and the second nonlinear characteristic relationship L3) and a set of linear relationships (linear relationship L2), wherein the linear relationship L2 is determined by the spring characteristics, and the second nonlinear characteristic relationship L3 can be obtained by testing in the laboratory. The first nonlinear characteristic relationship L1, the linear relationship L2 and the second nonlinear characteristic relationship L3 are superimposed, and through laboratory testing, the linear relationship between the input signal I and the output flow Q can be artificially established. Thus, the specific function of the first nonlinear characteristic relationship L1 is obtained, and it is solidified into the embedded software of the pilot valve 1. In this way, the proportional control of the flow is realized, and a proportional valve suitable for gas environment that can accurately control the flow is realized.

[0051] The best embodiment of the present invention has been described, and various changes or modifications made by those skilled in the art will not depart from the scope of the present invention.

Claims

1. A pilot-operated open-loop control proportional flow valve, comprising a pilot valve (1) and a main valve (2) connected to each other, characterized in that The pilot valve (1) is provided with a pilot valve air inlet (P1), a pilot valve pressure relief port (R1) and a pilot valve control port (K1), and the pilot valve (1) comprises a controller (11) and a pilot valve module (12); the main valve (2) is provided with a main valve air supply port (P2), a main valve exhaust port (R2), a main valve control port (K2), a working port (A) and a pilot valve interface (2a), and the main valve (2) comprises a valve body (21), a valve core (22), a left end cover (23) and a valve body (24). ), a right end cover (24) and a spring (25), wherein the spring (25) is arranged between the valve core (22) and the left end cover (23); the pilot valve control port (K1) of the pilot valve (1) is connected to the main valve control port (K2) of the main valve (2), and the main valve control port (K2) of the main valve (2) is connected to the right control chamber (2b) of the main valve (2); the pressure of the pilot valve control port (K1) of the pilot valve (1) and the input signal present a first nonlinear characteristic relationship (L1), the pressure of the main valve control port (K2) of the main valve (2) and the valve port opening of the main valve (2) present a linear relationship (L2), and the valve port opening of the main valve (2) and the output gas flow present a second nonlinear characteristic relationship (L3); through laboratory testing, the output gas flow and the input signal are corrected to form a linear relationship, and the pressure value of the intermediate variable pilot valve control port (K1) is solidified into the controller (11); The pilot valve module (12) comprises an intake solenoid valve (12a), an exhaust solenoid valve (12b), a pressure sensor (12c) and an air path base plate (12d); the controller (11) is control-connected to the intake solenoid valve (12a) and the exhaust solenoid valve (12b); the pressure sensor (12c) is feedback-connected to the controller (11); the intake solenoid valve (12a) is arranged between the intake port (P1) of the pilot valve and the control port (K1) of the pilot valve; and the exhaust solenoid valve (12b) is arranged between the pressure relief port (R1) of the pilot valve and the control port (K1) of the pilot valve.

2. A pilot-operated open-loop controlled proportional flow valve according to claim 1, characterized in that: The controller (11) comprises a processor (11a), an M / A analog-to-digital converter (11b), an input / output interface circuit (11c), a display circuit (11d), a power supply (11e) and a solenoid valve drive circuit (11f).

3. A pilot-operated open-loop controlled proportional flow valve according to claim 2, characterized in that: A convex block (24a) is provided at the left end of the right end cover (24), and a right control chamber (2b) is formed between the outer periphery of the convex block (24a) and the inner wall of the valve body (21).

4. A pilot-operated open-loop controlled proportional flow valve according to claim 3, characterized in that: A groove (22a) is provided in the middle of the valve core (22).

5. The pilot-operated open-loop controlled proportional flow valve according to claim 4 is characterized in that: A sealing ring (26) is provided between the right end cover (24) and the valve body (21).

6. A pilot-operated open-loop controlled proportional flow valve according to claim 5, characterized in that: The right end cover (24) is fixed to the valve body (21) by means of screws (27).

7. A pilot-operated open-loop controlled proportional flow valve according to claim 6, characterized in that: An outer cover shell (13) is arranged outside the controller (11) and the pilot valve module (12).

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