Proportional valve structure capable of performing differential pressure feedback regulation

Abstract

The invention discloses a proportional valve structure capable of performing differential pressure feedback regulation, which comprises a valve body used for forming a fluid channel; the valve port is arranged in the valve body, and the valve element assembly comprises a movable iron core, a sealing piece and an elastic feedback element and is used for adjusting the opening degree of the valve port; the driving device comprises a static iron core, a coil and a magnetic conductive component, and the coil is used for generating electromagnetic force to drive the movable iron core to move; the pressure difference feedback mechanism comprises a diaphragm and a ventilation structure, the diaphragm is arranged between the valve element assembly and the fluid channel, the ventilation structure is used for guiding fluid in the fluid channel into the position above the diaphragm to form feedback force related to the pressure difference of a fluid inlet and a fluid outlet, and the feedback force acts on the valve element assembly; the opening degree of the valve port is automatically adjusted according to changes of inlet and outlet pressure difference so as to stabilize fluid flow. The valve is simple in structure, the opening degree of the valve port can be adjusted through feedback of the pressure difference of the inlet and the outlet without additional flow detection for closed-loop control, and therefore the flow is stabilized within a certain range.

Description

Technical Field

[0001] The invention belongs to the technical field of fluid proportional valves and relates to a proportional valve structure capable of performing pressure difference feedback regulation. Background Art

[0002] As a basic fluid control component, the fluid proportional control valve has the characteristics of stepless adjustment, high precision and fast response. It is widely used in many fields such as industrial automation, aerospace, medical equipment, scientific instruments, etc., and can realize rapid and continuous regulation of flow and pressure.

[0003] The valve core of the fluid proportional valve is driven by a proportional solenoid, and the valve opening is changed by changing the displacement of the valve core. The outlet flow of the fluid proportional valve is not only related to the valve opening, but also closely related to the inlet and outlet pressure difference. When the inlet and outlet pressure difference changes, the flow will change even if the valve opening remains unchanged.

[0004] In the application of fluid proportional valves, it is often necessary to adjust and control the flow. In certain working conditions, the pressure difference before and after the fluid proportional valve is prone to fluctuate, causing flow changes. In order to ensure a constant output flow, it is often necessary to introduce a flow meter for flow detection and perform closed-loop control to adjust the fluid proportional valve opening in real time. Currently, there is no fluid proportional valve structure on the market that can adjust based on pressure differential feedback to ensure stable output flow. Summary of the invention

[0005] The object of the present invention is to provide a proportional valve structure capable of performing pressure difference feedback regulation to solve the problems raised in the above background.

[0006] The present invention comprises:

[0007] A valve body, used to form a fluid passage;

[0008] A valve port is arranged in the valve body and is used to control the on / off and flow rate of the fluid;

[0009] A valve core assembly, comprising a moving iron core, a sealing member and an elastic feedback element, wherein the moving iron core is connected to the sealing member and is used to adjust the valve opening;

[0010] A driving device, comprising a static iron core, a coil and a magnetic conductive component, wherein the static iron core cooperates with the moving iron core, and the coil is used to generate an electromagnetic force to drive the moving iron core to move;

[0011] The pressure difference feedback mechanism includes a diaphragm and a ventilation structure. The diaphragm is arranged between the valve core assembly and the fluid channel. The ventilation structure is used to introduce the fluid in the fluid channel to the top of the diaphragm to form a feedback force related to the fluid inlet and outlet pressure difference. The feedback force acts on the valve core assembly to automatically adjust the valve opening according to the change of the inlet and outlet pressure difference to stabilize the fluid flow.

[0012] The present invention has the following beneficial effects:

[0013] 1. A fluid proportional valve structure is provided, which can adjust the opening degree according to the inlet and outlet pressure difference to achieve flow stability.

[0014] 2. Simple structure, low cost, no need to introduce flow measurement for closed-loop control, and can achieve flow stability.

[0015] 3. Using the inlet air pressure for sealing can reduce the pre-pressure of the spring, thereby reducing the impact on the valve port seal due to the spring force when the fluid proportional valve works frequently, and prolonging its service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the structure of an embodiment of the present application.

[0017] Figure 2 It is a schematic diagram of laser welding of the static iron core and the support tube in an embodiment of the present application.

[0018] Figure 3 It is a schematic diagram of the reed structure of an embodiment of the present application.

[0019] Figure 4 It is an exploded view of the installation of the embodiment of the present application.

[0020] Figure 5 It is a schematic diagram of the internal fluid flow direction of an embodiment of the present application.

[0021] Figure 6 It is a schematic diagram of the diaphragm structure of an embodiment of the present application.

[0022] Figure 7 This is a force analysis diagram of the valve core system of an embodiment of the present application. DETAILED DESCRIPTION

[0023] In order to make the objectives, technical solutions and advantages of the present disclosure more clearly understood, the present disclosure is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0024] In the embodiment of the present disclosure, the fluid proportional valve structure is as follows: Figure 1 As shown, it is mainly composed of a valve body 1, a valve port 2, a reed 3, a reed pressure plate 4, a diaphragm 5, a support tube 6, a magnetic housing 7, a static iron core 8, a moving iron core 9, a spring 10, a coil 11, a magnetic bottom plate 12, a valve port seal 13, and a bolt 14.

[0025] The valve body 1 is made by a casting process, and the material can be brass or stainless steel. The valve body 1 is connected to the valve port 2 by an interference fit, and sealant can be applied during the connection to ensure sealing. Considering that the operating pressure range and flow range of the fluid proportional valve are closely related to the valve port caliber, the valve body 1 can be combined with valve ports 2 of different calibers to form different caliber combinations, thereby adapting to different pressure and flow usage scenarios and increasing the flexibility of the fluid proportional valve.

[0026] The valve core system consists of a moving iron core 9, a diaphragm 5, a reed 3 and a valve port seal 13. The bottom of the valve port seal 13 is formed of a rubber part by vulcanization process, and is pre-pressed on the valve port 2 by the top spring 10 to achieve sealing. The static iron core 8 adopts a disc electromagnet solution, which has two cone angles at the basin mouth, and can provide a large output force within a short stroke range, thereby reducing the power consumption of the electromagnet. The structural parameters can be optimized through magnetic field simulation software to achieve optimal design.

[0027] The static iron core 8 is connected to the support tube 6 by laser welding. Figure 2 As shown, while ensuring reliable support connection, the weld is required to be sealed and leak-free. The moving iron core 9 and the valve port seal 13 are connected by threads, and a reed 3 and a diaphragm 5 are installed in the middle. The reed 3 provides radial support. The reed 3 is made of stainless steel and has special profiles etched by laser, such as Figure 3 As shown, the radial support stiffness is ensured, and the moving iron core 9 is prevented from contacting and colliding with the support tube 6 during movement, thereby generating friction and increasing the hysteresis of the fluid proportional valve.

[0028] The diaphragm 5 is used to ensure sealing inside the fluid proportional valve, and feedback adjustment is performed. The reed 3 is fixed to the internal step of the valve body 1 by the reed pressure plate 4. The coil 11 is composed of an enameled wire with a certain number of turns wound on the coil frame, and the wire is led through the outlet hole on the magnetic shell 7. When the coil 11 is energized, the coil 11 generates a magnetic field, and a closed magnetic circuit is formed by the moving iron core 9, the static iron core 8, the magnetic shell 7 and the magnetic bottom plate 12. An electromagnetic force proportional to the current can be applied to the moving iron core 9. The moving iron core 9, the static iron core 8, the magnetic shell 7, and the magnetic bottom plate 12 can be made of electrical pure iron material, which has excellent magnetic properties such as high magnetic permeability, low coercive force, low hysteresis loss and high saturation magnetic induction intensity, which can enhance the electromagnetic force and reduce power consumption.

[0029] The exploded diagram of the overall installation of the fluid proportional valve is as follows: Figure 4As shown, the installation process is as follows: first, the valve body 1 and the valve port 2 are combined through an interference fit to form a valve body assembly, the coil 11 is bonded to the magnetic base plate 12, and inserted into the support tube 6, and then the static iron core 9 and the support tube 6 are laser welded by tooling to form a static iron core assembly, and then the moving iron core 9, the diaphragm 5, the reed 3 and the valve port seal 13 are combined, and the diaphragm 5 and the reed 3 are compressed by threaded connection to form a moving iron core assembly, the valve core system is placed on the step of the valve body 1, and the reed pressure plate 4 is placed on the reed 3, the spring 10 is placed in the step of the moving iron core 9, and then the laser-welded static iron core assembly is placed, and the valve body assembly, the static iron core assembly and the moving iron core assembly are connected by bolts 14, and finally the magnetic outer shell 11 is inserted, and the magnetic outer shell 11 and the magnetic base plate 12 are laser welded.

[0030] It can be seen that when the fluid flows through the valve body 1 from the inlet, Figure 5 As shown, a part of the flow is diverted through the valve body and then diverted through the diaphragm vent flow channel into the upper chamber. The pressure of the upper chamber can be considered to be consistent with the inlet pressure. A part of the flow flows through the valve nozzle to the outlet. It can be seen that after the fluid is throttled and decompressed at the valve nozzle, it does not pass through the relevant throttling and decompression structure. Therefore, it can be considered that the average pressure of the valve cavity is consistent with the outlet pressure. Then the upper part of the diaphragm 5 is the inlet pressure, and the lower part is the outlet pressure. The diaphragm 5 has a certain elasticity, and it can obviously be adjusted by the upper and lower pressure differences. The structure of the diaphragm 5 is shown in FIG. Figure 6 As shown, a vent groove is provided on one side, which can introduce the inlet fluid to the top of the diaphragm 5 and isolate and seal the air chamber above the diaphragm 5 from the outside. The diaphragm 5, the moving iron core 9, the valve port seal 13 and the reed 3 form a valve core system. In order to increase the strength and pressure resistance, a composite material of nylon cloth is added inside the rubber diaphragm in this embodiment.

[0031] The working principle of this embodiment is described as follows:

[0032] like Figure 1 As shown, when the coil is not energized, the pre-pressure of the spring 10 and the air pressure in the upper chamber press the valve core assembly tightly against the valve seat, and the sealing is achieved by the rubber part at the valve port seal 13. When the supply current of the coil 11 is gradually increased, the electromagnetic force on the moving iron core 9 is gradually increased. When the upward force on the valve core system exceeds the downward force, the valve port opens, and the fluid generates flow through the valve port. At this time, due to the proportional output characteristics of the proportional valve solenoid, the electromagnetic force is linearly related to the current, resulting in a linear correlation between the valve port opening and the current. When the inlet and outlet pressure difference does not change and the supply current is constant, the valve port opening is constant, and the outlet flow is fixed.

[0033] When the inlet pressure increases and the outlet pressure remains unchanged, the gas pressure on the diaphragm 5 increases, which will inevitably cause the valve core to move in the direction of decreasing the opening, hindering the increase in flow caused by the increase in the inlet and outlet pressure difference. On the contrary, when the inlet pressure remains unchanged and the outlet pressure increases, the gas pressure on the diaphragm 5 decreases, which will inevitably cause the valve core to move in the direction of increasing the opening, hindering the decrease in flow caused by the decrease in the inlet and outlet pressure difference. For the case where the inlet and outlet pressures decrease, the same conclusion can be drawn by the same logic. The direction of the change in the valve opening caused by the gas pressure will definitely be opposite to the direction of the change in the flow, thereby preventing the change in flow and balancing the impact of the inlet and outlet pressure difference.

[0034] The force analysis of the valve core system is as follows: Figure 7 As shown, it is affected by fluid impact force, electromagnetic force, spring force, feedback force and gravity, and maintains balance under the action of these forces.

[0035] mg+F b +F0+kx=F e +F g

[0036] x=(F e +F g -△P·S-F0-mg) / k

[0037] Where m is the mass of the moving iron core assembly, F b is the feedback force, F b =△P·S, S is the force-bearing area of ​​the diaphragm, △P is the inlet and outlet pressure difference, F0 is the spring preload, the initial preload of the diaphragm can be ignored, k is the superimposed axial stiffness of the diaphragm and the spring, F e is the electromagnetic force, F g is the fluid impact force, and x is the valve core displacement opening.

[0038] For a valve port with a diameter of D, at an opening of x, its flow area is A = πDx. The valve port throttle hole can be considered as a thin-walled small hole. When the flow rate is small and the compressibility effect is ignored, the flow through the throttle hole can be calculated by the following formula:

[0039]

[0040] In the formula, q m is the mass flow rate, in kg / s, C d is the flow coefficient, A is the flow area, unit is m 2 , ρ is the fluid density;

[0041]

[0042] Considering the case where the inlet and outlet pressure difference remains unchanged, F eThe electromagnetic force can be considered as a linear function of the current I. According to the calculation formula, as the current increases, the electromagnetic force increases. When the electromagnetic force is not enough to offset the spring force and gravity, the valve core will not move. When the electromagnetic force increases beyond the critical value, the valve core begins to move. Since the output electromagnetic force of the proportional solenoid is proportional to the current, the final output flow is proportional to the current.

[0043] When the inlet and outlet pressure difference changes, intuitively, when the pressure difference increases, if the valve core opening remains unchanged, the flow rate will inevitably increase. However, the increase in feedback force will cause the valve core opening to decrease, which to a certain extent offsets the effect of the increased pressure difference, and vice versa. The following is further explained in conjunction with mathematical formulas, simplifying the above calculation formula to:

[0044]

[0045] C2=△P·S

[0046] q m =C1△P 1 / 2 -C2△P 3 / 2

[0047] Derivative:

[0048]

[0049] Function extreme points:

[0050] Substituting the extreme point into the original function, we get:

[0051]

[0052] The trend of the function graph is to rise from the origin of the graph first, then fall after reaching the extreme point, and the overall shape is convex first and then convex. Obviously, near the extreme point, as the pressure difference increases or decreases, the flow rate will decrease. Through the calculation formula, the working pressure difference range can be flexibly selected, which can include the extreme point or not, and various parameters can be adjusted to reduce the rate of change of flow with pressure difference in the working range, so as to control the outlet flow fluctuation within an acceptable range and stabilize the flow.

[0053] The above are all preferred embodiments of the present application, and are not intended to limit the protection scope of the present application. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application should be included in the protection scope of the present application.

[0054] Finally, it should be noted that the above examples are only some specific embodiments of the present invention. Obviously, the present invention is not limited to the above examples, and there are many variations. All variations that can be directly derived or associated with the content disclosed by a person skilled in the art should be considered as the protection scope of the present invention.

Claims

1. A proportional valve structure capable of differential pressure feedback regulation, characterized in that: include: A valve body (1) is used to form a fluid passage; A valve port (2) is arranged in the valve body (1) and is used to control the on / off and flow rate of the fluid; A valve core assembly, comprising a moving iron core (9), a sealing member (13), and an elastic feedback element, wherein the moving iron core (9) is connected to the sealing member (13) and is used to adjust the valve opening; A driving device, comprising a static iron core (8), a coil (11) and a magnetic conductive component, wherein the static iron core (8) cooperates with the moving iron core (9), and the coil (11) is used to generate an electromagnetic force to drive the moving iron core (9) to move; A pressure differential feedback mechanism comprises a diaphragm (5) and a venting structure, wherein the diaphragm (5) is arranged between the valve core assembly and the fluid channel, and the venting structure is used to introduce the fluid in the fluid channel to the top of the diaphragm (5) to form a feedback force related to the fluid inlet and outlet pressure differential, and the feedback force acts on the valve core assembly to automatically adjust the valve opening according to the change of the inlet and outlet pressure differential to stabilize the fluid flow.

2. A proportional valve structure capable of differential pressure feedback regulation according to claim 1, characterized in that: The elastic feedback element comprises a leaf reed (3) and a spring (10); the leaf reed (3) is made of stainless steel and has a profile formed by laser etching, so as to provide radial support and prevent the moving iron core (9) from contacting the support tube (6) and generating friction during movement.

3. A proportional valve structure capable of pressure difference feedback regulation according to claim 1, characterized in that: The diaphragm (5) of the differential pressure feedback mechanism is made of a rubber material and has a high-strength fiber cloth embedded inside. The fiber cloth is polyester fiber or nylon and is used to increase the strength and pressure resistance of the diaphragm.

4. A proportional valve structure capable of pressure difference feedback regulation according to claim 1 or 3, characterized in that: The ventilation structure comprises a ventilation groove arranged on the diaphragm (5), wherein the ventilation groove is used to introduce the fluid at the inlet into the upper chamber above the diaphragm, so that the pressure of the upper chamber is consistent with the inlet pressure, and the pressure below the diaphragm is consistent with the outlet pressure, thereby realizing pressure difference feedback regulation through the elastic deformation of the diaphragm.

5. The proportional valve structure capable of differential pressure feedback regulation according to claim 1, characterized in that: The driving device further comprises a magnetically conductive shell (7) and a magnetically conductive bottom plate (12); the magnetically conductive shell (7) and the magnetically conductive bottom plate (12) are made of electrical pure iron material and have high magnetic permeability, low coercive force, low hysteresis loss and high saturation magnetic induction intensity, and are used to enhance electromagnetic force and reduce power consumption.

6. A proportional valve structure capable of pressure difference feedback regulation according to claim 1 or 5, characterized in that: The static iron core (8) adopts a disc-type electromagnet design, and a cone-angle structure is provided at the mouth of the disc, which can provide a large output force within a shorter stroke range, thereby reducing the power consumption of the electromagnet.

7. The proportional valve structure capable of pressure difference feedback regulation according to claim 1, characterized in that: The valve body (1) and the valve port (2) are connected by interference fit, and a sealant is applied to the connection to ensure the sealing performance; the valve body (1) can be matched with valve ports (2) of different diameters to meet different pressure and flow requirements.

8. A proportional valve structure capable of pressure difference feedback regulation according to claim 7, characterized in that: The valve core assembly further comprises a reed pressure plate (4), which is used to fix the reed (3) and is installed on an internal step of the valve body (1).

9. The proportional valve structure capable of pressure difference feedback regulation according to claim 1, characterized in that: The bottom of the sealing member (13) is formed into a rubber member through a vulcanization process, and the rubber member is pressed against the valve port (2) under the pre-pressure of the spring (10) to achieve sealing.

10. The proportional valve structure capable of pressure difference feedback regulation according to claim 1, characterized in that: The movement direction of the valve core assembly is perpendicular to the flow direction of the fluid, and the elastic deformation of the diaphragm (5) can automatically adjust the valve opening according to the change of the inlet and outlet pressure difference to maintain the stability of the flow rate.

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