A safety valve with a pressure transfer device

Abstract

The present invention discloses a safety valve with a pressure transfer device, which includes a valve core and a spring. The top surface of the valve core is provided with an inlet, and a pressure transfer device is arranged below the valve core. The end face of the pressure transfer device and the inner cavity of the lower part of the valve core enclose a closed cavity, and the inlet of the valve core communicates with the closed cavity through a throttle hole; the pressure transfer device is fixed, and the pressure of the oil fluid entering from the inlet of the valve core is jointly borne by the pressure transfer device and the spring. Both ends of the valve core of this valve are acted on by oil pressure, most of the pressure borne by the spring is transferred to the pressure transfer device, the requirement for the spring stiffness is reduced, and at the same time, the spring parameters can be matched by adjusting the area difference of the valve, greatly reducing the design difficulty of the spring.

Description

Technical Field

[0001] The present invention belongs to the technical field of valve design, and relates to a safety valve with a pressure transfer device. Background Art

[0002] In an aeroengine fuel control system, to ensure that the load of the fuel pump is not too large, a safety protection function is generally achieved through a safety valve. Traditional safety relief devices have three typical structures:

[0003] 1. Direct-acting safety valve: It has high sensitivity, but is only suitable for low-pressure and small-flow conditions. When controlling higher pressure or higher flow, a hard spring with a larger stiffness is required, which is difficult to adjust and assemble. Moreover, even a slight change in the valve port causes a large pressure fluctuation.

[0004] 2. Direct-acting extended safety valve: An improved structure based on the direct-acting safety valve, making the opening pressure greater than the closing pressure, and improving the performance of maintaining a constant system pressure.

[0005] 3. Safety valve + oil return valve: The main valve spring only requires a very small stiffness. When the change in the oil return amount causes a change in the spring compression amount, the pressure at the oil inlet changes little. Its response is not as sensitive as that of the direct-acting type, and it is suitable for large-flow and high-pressure conditions, but it occupies a large space.

[0006] With the gradually increasing requirements for pressure in aeroengines, since all the inlet pressures of traditional safety valves act on the spring, a higher spring stiffness is required, increasing the design difficulty of the spring. Summary of the Invention

[0007] Object of the Invention: To solve the above problems, the present invention provides a safety valve with a pressure transfer device, which transfers most of the pressure borne by the spring to the pressure transfer device, reducing the pressure on the spring and greatly reducing the design difficulty of the spring.

[0008] Technical Solution of the Present Invention:

[0009] A safety valve with a pressure transfer device includes a valve core and a spring. The top surface of the valve core is provided with an inlet. A pressure transfer device is arranged below the valve core. The end surface of the pressure transfer device and the inner cavity of the lower part of the valve core enclose a closed cavity. The inlet of the valve core communicates with the closed cavity through a throttle hole. The pressure transfer device is fixed, and the pressure of the oil entering from the inlet of the valve core is jointly borne by the pressure transfer device and the spring.

[0010] Preferably, the valve core is arranged in the inner hole of the valve sleeve and can move in the valve sleeve.

[0011] Preferably, the lower part of the pressure transfer device is arranged in an adjusting nut connected to the valve sleeve, and the bottom surface of the pressure transfer device is supported by the adjusting nut.

[0012] Preferably, the spring is disposed between the valve core and the lower part of the pressure transfer device.

[0013] Preferably, the cross-sectional area of the closed cavity is smaller than the cross-sectional area of the inlet of the valve core.

[0014] Preferably, the adjusting nut is threadedly connected to the inner hole of the valve sleeve.

[0015] Preferably, the locking nut is threadedly connected to the outer circumferential surface of the adjusting nut.

[0016] Preferably, an oil inlet hole is formed in the side wall of the valve sleeve, and the oil can enter the spring cavity where the spring is installed from the oil inlet hole.

[0017] Preferably, a plunger connection is adopted between the pressure transfer device and the valve core, and a dynamic seal is arranged between the pressure transfer device and the valve core.

[0018] The main advantages of the present invention are as follows: both ends of the valve core are acted on by oil pressure, most of the pressure borne by the spring is transferred to the pressure transfer device, the requirement for the spring stiffness is reduced, and at the same time, the spring parameters can be matched by adjusting the area difference of the valve, greatly reducing the design difficulty of the spring. Brief Description of the Drawings

[0019] Figure 1 Structural schematic diagram of a safety valve with a pressure transfer device according to the present invention.

[0020] Figure 2 Structural schematic diagram of the valve core.

[0021] Figure 3 Structural schematic diagram of the valve sleeve.

[0022] Figure 4 Structural schematic diagram of the pressure transfer device.

[0023] In the figure: 1-valve core, 2-valve sleeve, 3-pressure transfer device, 4-spring, 5-locking nut, 6-adjusting nut. Detailed Description of the Invention

[0024] The present invention will be further described below in conjunction with the drawings and its working principle.

[0025] A safety valve with a pressure transfer device includes a valve core 1, a valve sleeve 2, a pressure transfer device 3, a spring 4, a locking nut 5, and an adjusting nut 6.

[0026] Among them, the valve sleeve 2 is fixed to provide support for the axial movement of the valve core 1; the valve core 1 is arranged in the inner hole of the valve sleeve 2, and there is a clearance fit between the outer circumferential surface of the upper part of the valve core 1 and the inner hole of the valve sleeve 2. The valve core 1 can move in the inner hole of the valve sleeve 2. The inner hole of the valve sleeve 2 is provided with a structure for axially limiting the valve core 1, and the top surface of the valve core 1 is provided with an inlet; one end of the pressure transfer device 3 is connected to the lower part of the valve core 1 in a plunger type through a dynamic seal, and a closed cavity is formed between the end surface of the pressure transfer device 3 and the inner cavity of the valve core 1. The lower part of the pressure transfer device 3 is arranged in the adjusting nut 6 and supported by the adjusting nut 6. The adjusting nut 6 is threadedly connected to the inner hole of the valve sleeve 2; to ensure that the adjusting nut 6 does not loosen under pressure, the locking nut 5 is threadedly connected to the outer circumferential surface of the adjusting nut 6 to press the adjusting nut 6 tightly; a throttle hole is provided on the valve core 1 so that the inlet of the valve core 1 is communicated with the closed cavity to keep the pressure in the closed cavity equal to the inlet pressure; to ensure that the valve core 1 can be opened normally, the cross-sectional area of the inlet must be larger than the cross-sectional area of the closed cavity; one end of the spring 4 acts on the pressure transfer device 3, and the other end acts on the valve core 1. An oil inlet hole is provided on the side wall of the valve sleeve 2, and the oil can enter the spring cavity where the spring 4 is located from the oil inlet hole. The pressure generated by the oil entering the spring cavity on the valve core 1 is the oil return pressure F 回 。

[0027] Figure 3 At the A position in, it is required to grind and color-match the inspection ring band, and discontinuity is not allowed to ensure the sealing performance when the valve core is closed. Figure 4 The coaxiality requirement of the pressure transfer device in is 0.05 mm to ensure uniform stress on the pressure transfer device.

[0028] The fuel with a pressure of P1 enters from the inner hole of the valve sleeve 2 and acts on the inlet of the valve core 1. The cross-sectional area of the inlet of the valve core 1 is S1. The fuel enters the closed cavity through the throttle hole, making the pressure in the closed cavity equal to the inlet pressure. The cross-sectional area of the closed cavity is S2. The pressure of the fuel with a pressure of P1 acts on the closed cavity and the end surface of the pressure transfer device 3 at the same time, where S1 > S2. At the same time, the valve core 1 is subjected to an upward oil return pressure F 回 and spring force F 弹 。When P1×S1 = P1×S2 + F 回 +F 弹 , P1 is the critical point for the valve core to open. At this time, F 弹 = P1×(S1 - S2) - F 回 , F 回 is usually small, even negligible. F 弹 mainly depends on the area difference between S1 and S2. This area difference can be adjusted adaptively according to parameters such as the installation space of the spring 4 and the material properties of the spring, greatly reducing the design difficulty of the spring 4.

[0029] The working principle of the present invention

[0030] When the inlet pressure P1 rises to be greater than the critical pressure, that is, when P1×S1>P1×S2+F 回 +F 弹 the spool 1 compresses the spring 4 and moves downward. The oil discharge channel of the safety valve becomes larger as the spool stroke increases, and the oil discharge flow rate increases accordingly, so as to ensure that the inlet pressure does not exceed the limit value. When the inlet pressure P1 drops to be less than the critical pressure, that is, when P1×S1<P1×S2+F 回 +F 弹 the spring 4 pushes the spool 1 upward and the oil discharge channel closes.

[0031] The above embodiments are only for illustrating the technical concept and features of the present invention. The purpose is to enable those skilled in the technical field to understand the content of the present invention and implement it accordingly, and it cannot be used to limit the protection scope of the present invention. Any equivalent transformation or modification made according to the spirit and essence of the present invention should be covered within the protection scope of the present invention. The technologies, shapes, and structures not described in detail in the present invention are all well-known technologies.

Claims

1. A safety valve with a pressure transfer device, characterized in that, It includes a valve core (1) and a spring (4). The top surface of the valve core (1) has an inlet. A pressure transfer device (3) is provided at the lower part of the valve core (1). The end face of the pressure transfer device (3) and the inner cavity at the lower part of the valve core enclose a closed cavity. The inlet of the valve core (1) communicates with the closed cavity through a throttle hole. The pressure transfer device (3) is fixed, and the pressure transfer device (3) and the spring (4) jointly bear the pressure of the hydraulic oil entering from the inlet of the valve core (1). An oil inlet hole is provided on the side wall of the valve sleeve (2), and oil can enter the spring chamber where the spring (4) is located through the oil inlet hole. The pressure generated by the oil entering the spring chamber on the valve core (1) is the oil return pressure F 回 ; Fuel oil with a pressure of P1 enters through the inner hole of the valve sleeve (2) and acts on the inlet of the valve core (1). The cross-sectional area of the inlet of the valve core (1) is S1. The fuel oil enters the closed chamber through the throttle hole, making the pressure in the closed chamber equal to the inlet pressure. The cross-sectional area of the closed chamber is S2. The pressure of the fuel oil with a pressure of P1 acts on the end face of the closed chamber and the pressure transfer device (3) at the same time. Among them, S1 > S2. At the same time, the valve core (1) is subjected to an upward oil return pressure F 回 and a spring force F 弹 ; when P1×S1 = P1×S2 + F 回 + F 弹 , P1 is the critical point for the valve core to open. At this time, F 弹 = P1×(S1 - S2)-F 回 , F 回 is usually small, and F 弹 depends on the area difference between S1 and S2.

2. The safety valve with a pressure transfer device as claimed in claim 1, wherein The valve core (1) is arranged in the inner hole of the valve sleeve (2) and can move within the valve sleeve (2).

3. The safety valve with a pressure transfer device according to claim 2, characterized in that, The lower part of the pressure transfer device (3) is arranged in an adjusting nut (6) connected to the valve sleeve (2), and the bottom surface of the pressure transfer device (3) is supported by the adjusting nut (6).

4. The safety valve with a pressure transfer device according to claim 2, characterized in that, The spring (4) is arranged between the valve core (1) and the lower part of the pressure transfer device (3).

5. The safety valve with a pressure transfer device according to claim 3, characterized in that, The adjusting nut (6) is threadedly connected to the inner hole of the valve sleeve (2).

6. The safety valve with a pressure transfer device according to claim 3, characterized in that, The lock nut (5) is threadedly connected to the outer circumferential surface of the adjusting nut (6).

7. The safety valve with a pressure transfer device according to claim 1, characterized in that, A plunger connection is adopted between the pressure transfer device (3) and the valve core (1), and a dynamic seal is provided between the pressure transfer device (3) and the valve core (1).

Images