A metering differential pressure valve that maintains a constant flow rate when the inlet pressure changes

Abstract

This invention belongs to the field of hydraulic machinery technology and discloses a device and control method for maintaining a constant flow rate when the inlet pressure changes. The device includes: a plug, a stop block, a valve, a bushing, a spring, and a spring seat. The stop block is threadedly connected to the housing and is used to fix the bushing and limit the valve position. The plug is threadedly connected to the stop block. The spring is located on the right side of the valve, and the spring seat is located to the right of the spring. Compared with existing metering-differential pressure-return oil mode control for constant flow rate, this structure is simple, requiring only one valve assembly and some nozzles. This structure does not require an electronic controller, electro-hydraulic servo valve, or displacement sensor for control; it achieves constant flow rate by matching the throttle valve with the spring and the metering valve orifice.

Description

Technical Field

[0001] This invention belongs to the field of hydraulic machinery technology, and in particular relates to a metering differential pressure valve that maintains a constant flow rate when the inlet pressure changes. Background Technology

[0002] Currently, hydraulic mechanical devices primarily maintain a constant outlet flow rate when the inlet pressure changes, mainly through differential pressure valves, metering valves, and return valves. Figure 1 As shown, the electronic controller controls the electro-hydraulic servo valve to stabilize the metering valve at a certain position. The differential pressure valve ensures that the pressure before and after the metering valve remains constant. When the fuel inlet flow increases, the differential pressure valve controls the combined return valve to increase the fuel discharge, thus keeping the outlet flow of the metering valve constant. This type of constant flow device has many control components and a relatively complex structure. Summary of the Invention

[0003] This invention proposes a metering differential pressure valve that maintains a constant flow rate when the inlet pressure changes. Compared to existing metering-differential-return oil mode control for constant flow, this structure is simpler, requiring only one valve assembly and some nozzles. This structure eliminates the need for an electronic controller, electro-hydraulic servo valve, and displacement sensor; instead, it achieves constant flow by matching a throttle valve with a spring and a metering orifice.

[0004] To achieve the above objectives, the present invention employs the following technical solution.

[0005] A metering differential pressure valve that maintains a constant flow rate when the inlet pressure changes, the device comprising: a plug 1, a stop block 2, a valve 3, a bushing 4, a spring 5, and a spring seat 6;

[0006] The stop block 2 is threadedly connected to the housing and is used to fix the bushing 4 and limit the position of the valve 3. The plug 1 is threadedly connected to the stop block 2.

[0007] The spring 5 is located on the right side of the valve 3, and the spring seat 6 is located on the right side of the spring 5 and is installed in the housing.

[0008] The features and further improvements of the technical solution of this invention are as follows:

[0009] (1) The device is provided with: a first inlet, a second inlet and an outlet;

[0010] The first inlet is connected to the fuel after the radiator, the second inlet is connected to the oil after the pump, the first inlet and the second inlet have the same pressure, and the outlet is connected to the fuel tank.

[0011] (2) The device further includes: a second throttle nozzle 7, a housing fixing hole 8, a first adjustable oil nozzle 9, and a second adjustable oil nozzle 10;

[0012] The fuel from the first inlet and the second inlet merges into the main oil circuit after passing through the first adjustable nozzle 9 and the second adjustable nozzle 10, enters the device's oil passage, and then returns to the fuel tank after passing through the metering orifice.

[0013] The first inlet fuel enters the left end of the valve after passing through the housing fixing hole 8, and then flows into the main oil circuit through the second throttle nozzle 7. After the first inlet and the second inlet fuel are mixed, a branch is separated to connect to the right cavity of the metering differential pressure valve.

[0014] (3) The device further includes: a third throttle nozzle 11 and a first throttle nozzle 12;

[0015] The third throttle nozzle 11 is located in the oil passage between the main oil passage and the right end of the valve 3, and the first throttle nozzle is located between the branch line that is separated after the first inlet and the second inlet fuel are mixed and the right cavity of the valve (3).

[0016] (4) When the pressure of the first inlet and the second inlet increases, the pressure in both the left and right chambers of the valve increases. With the matching of all adjustable nozzles, all throttle nozzles, springs and metering orifice areas, the pressure increase in the right chamber is less than that in the left chamber. The valve 3 moves to the right against the spring force, the metering window decreases, the pressure difference across the metering orifice increases, and the area decreases, ensuring that the outlet flow remains unchanged.

[0017] (5) Adjust the outlet flow of the device by changing the group of the first adjustable nozzle 9 or increasing the preload of the spring 5.

[0018] (6) Adjust the outlet flow rate of the device by changing the group of the first adjustable oil nozzle 9, the second adjustable oil nozzle 10, the first throttle nozzle 12, and the third throttle nozzle 11 or by increasing the preload of the spring 5.

[0019] (7) The third throttle nozzle 11 is a bidirectional throttle nozzle.

[0020] This invention provides a metering differential pressure valve that maintains a constant flow rate when the inlet pressure changes. It has a simple structure, consisting of only one valve assembly and some nozzles. This structure eliminates the need for an electronic controller, electro-hydraulic servo valve, and displacement sensor. By matching the throttle valve with a spring and metering orifice, it ensures that the product flow rate remains unaffected by changes in inlet pressure, thus enhancing system stability. Attached Figure Description

[0021] Figure 1 A schematic diagram of the existing metering-differential-oil return mode control constant flow device;

[0022] Figure 2 This invention provides a schematic diagram of a differential pressure metering valve that maintains a constant flow rate when the inlet pressure changes. Figure 1 ;

[0023] Figure 3 This invention provides a schematic diagram of a differential pressure metering valve that maintains a constant flow rate when the inlet pressure changes. Figure 2 ;

[0024] Wherein: a-return valve, b-differential pressure valve, c-metering valve, 1-plug, 2-stop block, 3-valve, 4-bulb, 5-spring, 6-spring seat, 7-second slit nozzle, 8-housing fixing hole, 9-first adjustable nozzle, 10-second adjustable nozzle, 11-third slit nozzle, 12-first slit nozzle. Detailed Implementation

[0025] The technical solution of the present invention will now be described in detail with reference to the accompanying drawings.

[0026] Compared to existing metering-differential-return oil mode control for constant flow, this invention provides a metering differential pressure valve that maintains a constant flow rate when the inlet pressure changes. It has a simple structure, requiring only one valve assembly and some nozzles. This structure eliminates the need for an electronic controller, electro-hydraulic servo valve, and displacement sensor; instead, it achieves constant flow rate by matching a throttle valve with a spring and a metering orifice.

[0027] This invention provides a metering differential pressure valve that maintains a constant flow rate when the inlet pressure changes, such as... Figure 2 As shown, the device includes: a plug 1, a stop block 2, a valve 3, a bushing 4, a spring 5, and a spring seat 6;

[0028] The bushing 4, spring seat 6, second throttle nozzle 7, first adjustable nozzle 9, and second adjustable nozzle 10 are installed in the housing mounting hole, and 8 is the housing fixing hole. Then, the spring 5, valve 3, stop block 2, and plug 1 are installed in sequence. The stop block is threaded to the housing and is used to fix the bushing and limit the position of the valve. The plug is threaded to the stop block.

[0029] The first inlet of this device connects to the fuel after the radiator, and the second inlet connects to the fuel after the pump. The pressures of the first and second inlets are basically the same. The outlet connects to the fuel tank. This device is mainly used to reduce the temperature of the radiator and prevent hot fuel from causing thermal shock to the fuel tank. The fuel from the first and second inlets flows into the main oil circuit after passing through the first adjustable nozzle 9 and the second adjustable nozzle 10, enters the device's oil passage hole, and then returns to the fuel tank after passing through the metering orifice. The fuel from the first inlet enters the left end of the valve 3 after passing through the housing oil passage hole 8, and then flows into the main oil circuit after passing through the second throttle nozzle 7. After the fuel from the first and second inlets mix, a branch line is split off and connects to the right cavity of the valve.

[0030] When the pressure at the first and second inlets increases, the pressure in both chambers of the valve also increases. With the nozzle, spring, and metering orifice area matched, the pressure increase in the right chamber is less than that in the left chamber. The valve then moves to the right against the spring force, reducing the metering window size and increasing the pressure difference across the metering orifice, thus decreasing its area and ultimately ensuring a constant outlet flow rate. The outlet flow rate can be adjusted by changing the group of the first adjustable nozzle 9 or by increasing the spring preload.

[0031] This invention provides a device and control method for maintaining a constant flow rate when the inlet pressure changes. Figure 3 The structure, Figure 3 Comparison Figure 2 A third-section nozzle 11 and a first-section nozzle 12 have been added. Figure 3 The flow rate of the device shown Figure 2 The device shown is large and can maintain a constant outlet flow rate within a certain pressure range. The outlet flow rate can be adjusted by changing the group of the first adjustable nozzle 9, the second adjustable nozzle 10, the first throttle nozzle 12, and the third throttle nozzle 11, or by increasing the preload of the spring. This invention provides a device and control method for maintaining a constant flow rate when the inlet pressure changes. It has a simple structure, requiring only one valve assembly and some nozzles. This structure does not require an electronic controller, electro-hydraulic servo valve, or displacement sensor. By matching the throttle valve with the spring and metering orifice, it ensures that the product flow rate is unaffected by changes in inlet pressure, enhancing system stability.

Claims

1. A differential pressure metering valve that maintains a constant flow rate when the inlet pressure changes, characterized in that, The differential pressure measuring valve includes: a plug (1), a stop block (2), a valve (3), a bushing (4), a spring (5), and a spring seat (6); the valve (3) is movably disposed inside the bushing (4), and the stop block (2) is disposed on the left side of the valve (3); The stop block (2) is threaded to the housing and is used to fix the bushing (4) and limit the position of the valve (3). The plug (1) is threaded to the stop block (2). The stop block (2), bushing (4), and valve (3) define the left cavity of the valve. The spring (5) is located on the right side of the valve (3), and the spring seat (6) is located on the right side of the spring (5); the spring seat (6), the bushing (4), and the valve (3) define the right cavity of the valve; The metering differential pressure valve is equipped with a first inlet, a second inlet, and an outlet. The first inlet is connected to the fuel after the radiator, the second inlet is connected to the oil after the pump, the first inlet and the second inlet have the same pressure, and the outlet is connected to the fuel tank; The metering differential pressure valve also includes: a second throttle nozzle (7), a housing fixing hole (8), a first adjustable oil nozzle (9), and a second adjustable oil nozzle (10). The fuel from the first inlet flows into the main oil circuit through the first adjustable nozzle (9) and the fuel from the second inlet flows into the second adjustable nozzle (10), enters the valve oil passage, and then passes through the metering orifice and the outlet in sequence before returning to the oil tank. The first inlet is connected to the left cavity of the valve (3) through the housing fixing hole (8). The oil passage between the housing fixing hole (8) and the left cavity of the valve (3) is connected to the main oil passage through the second throttle nozzle (7). After the fuel from the first inlet and the second inlet is mixed, a branch is separated to connect to the right cavity of the valve (3). When the pressure of the first inlet and the second inlet increases, the pressure in both the left and right chambers of the valve (3) increases. With the matching of all adjustable nozzles, all throttle nozzles, springs and metering orifice areas, the pressure increase in the right chamber is less than that in the left chamber. The valve (3) moves to the right against the spring force, the metering orifice area decreases, and the pressure difference before and after the metering orifice increases, ensuring that the outlet flow remains unchanged.

2. A differential pressure valve for maintaining a constant flow rate when the inlet pressure changes, as described in claim 1, characterized in that, The metering differential pressure valve also includes: a third flow nozzle (11) and a first flow nozzle (12). The third nozzle (11) is located in the oil passage between the main oil passage and the right cavity of the valve (3); The first throttle nozzle (12) is located between the oil passage between the housing fixing hole (8) and the left cavity of the valve (3) and the right cavity of the valve (3).

3. A differential pressure valve for maintaining a constant flow rate when the inlet pressure changes, as described in claim 1, characterized in that, The outlet flow rate of the metering differential pressure valve can be adjusted by changing the group of the first adjustable nozzle (9) or by increasing the pre-pressure of the spring (5).

4. A differential pressure valve for maintaining a constant flow rate when the inlet pressure changes, as described in claim 2, characterized in that, The outlet flow rate of the metering differential pressure valve can be adjusted by changing the group of the first adjustable nozzle (9), the second adjustable nozzle (10), the first throttle nozzle (12), and the third throttle nozzle (11) or by increasing the pre-pressure of the spring (5).

5. A differential pressure valve for maintaining a constant flow rate when the inlet pressure changes, as described in claim 2, characterized in that, The third nozzle (11) is a bidirectional throttling nozzle.

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