Pneumatic cut-off throttle device for security of steam turbine compressor unit

Abstract

The present invention relates to a pneumatic cut-off throttle device for the security of a steam turbine compressor unit, which includes a throttle housing, a hydraulic slide valve, and a pneumatic piston. The hydraulic slide valve is installed inside one side of the throttle housing, and the pneumatic piston is installed inside the other side. A gear-rack transmission mechanism is installed in the middle of the throttle housing. The piston rod of the pneumatic piston is connected to the piston rod of the hydraulic slide valve through the gear-rack transmission mechanism. The inner cavity of the hydraulic slide valve is connected to the power oil inlet, and the outer cavity is connected to the power oil outlet. An oil return port is provided below the inner cavity of the hydraulic slide valve. The upper chamber of the pneumatic piston is connected to the exhaust port of the compressor of the steam turbine compressor unit. The present invention realizes the back pressure protection of the compressor through the principles of pure hydraulic, pneumatic, and mechanical transmission, can avoid the problem of the failure of the back pressure protection function caused by the reliability problem of electrical components, and can also avoid the problem of the failure of the back pressure protection function caused by power failure.

Description

Technical Field

[0001] The present invention relates to a security device for a steam turbine compressor unit, and in particular to a security cut-off throttle device for a steam turbine compressor unit. Background Art

[0002] The press is provided with a protection shutdown function for high exhaust pressure (back pressure), generally overpressure power-off quick shutdown protection. There are two forms of overpressure power-off quick shutdown protection. One is to measure the exhaust port pressure through a sensor and judge through a controller. When the pressure exceeds the set pressure, the power supply of the prime mover is cut off to achieve shutdown; the other is through a pressure relay. When the pressure exceeds the set pressure, the power supply of the prime mover is cut off to achieve shutdown.

[0003] The original protection shutdown technology for high exhaust pressure is based on electrical components and equipment to achieve functions, and the reliability of protection actions needs to rely on the reliability of electrical components and electrical equipment. Therefore, it is necessary to design a pneumatic cut-off throttle to achieve the exhaust overpressure protection shutdown function without relying on the reliability of electrical equipment. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to propose a new pneumatic cut-off throttle device for the security of a steam turbine compressor unit, which can achieve the exhaust overpressure protection shutdown function without relying on the reliability of electrical equipment.

[0005] To achieve the above object, the technical solution of the present invention is: a pneumatic cut-off throttle device for the security of a steam turbine compressor unit, including a throttle housing, a hydraulic slide valve, and a pneumatic piston. The hydraulic slide valve is installed inside one side of the throttle housing, and the pneumatic piston is installed inside the other side. A gear-rack transmission mechanism is installed in the middle of the throttle housing. The piston rod of the pneumatic piston is connected to the piston rod of the hydraulic slide valve through the gear-rack transmission mechanism; the inner cavity of the hydraulic slide valve is connected to the power oil inlet, and the outer cavity is connected to the power oil outlet; an oil return port is provided below the inner cavity of the hydraulic slide valve; the upper chamber of the pneumatic piston is connected to the exhaust port of the compressor of the steam turbine compressor unit.

[0006] Further, a cover is installed on the upper part of the throttle housing.

[0007] Further, the gear-rack transmission mechanism is composed of a pneumatic piston rack, a hydraulic slide valve rack, and a gear. The upper end of the piston rod of the pneumatic piston is fixedly connected to the pneumatic piston rack, the upper end of the piston rod of the hydraulic slide valve is fixedly connected to the hydraulic slide valve rack, and the pneumatic piston rack and the hydraulic slide valve rack are connected by gear transmission.

[0008] Further, the power oil inlet is connected to the high-pressure oil outlet of the steam turbine screw compressor unit; the power oil outlet is connected to the high-pressure oil inlet of the main steam valve of the steam turbine screw compressor unit; the oil return port is connected to the oil tank of the steam turbine screw compressor unit.

[0009] Further, when the compressor exhaust pressure exceeds the rated pressure, compressed air introduced from the exhaust port of the compressor of the steam turbine compressor unit enters the upper chamber of the pneumatic piston. The pneumatic piston moves downward against the spring force, and then drives the hydraulic slide valve to move upward through the gear-rack transmission mechanism, thereby cutting off the high-pressure oil leading to the main steam valve and closing the emergency stop of the steam turbine main steam valve. The high-pressure oil below the hydraulic slide valve flows into the oil tank from the bottom oil return port.

[0010] Advantages of the present invention:

[0011] The pneumatic cut-off throttle device of the present invention has the following characteristics compared with the original "overpressure power-off quick shut-off protection":

[0012] 1) Achieve compressor backpressure protection through the principles of pure hydraulic, pneumatic, and mechanical transmission;

[0013] 2) Avoid the problem of the backpressure protection function failure caused by the reliability problem of electrical components;

[0014] 3) Avoid the problem of the backpressure protection function failure caused by power-off. Description of the Drawings

[0015] Figure 1 is the main sectional view of the structure of the pneumatic cut-off throttle device for the safety protection of the steam turbine compressor unit of the present invention;

[0016] Figure 2 is Figure 1 the sectional view along A-A in

[0017] Figure 3 is the application schematic diagram of the pneumatic cut-off throttle device of the present invention on the steam turbine screw compressor unit. Detailed Embodiment

[0018] The present invention will be further described below in conjunction with the drawings and embodiments.

[0019] As Figure 1, as shown in Figure 2, a pneumatic cut-off throttle device for the safety protection of a steam turbine compressor unit, comprising a throttle housing 1, a gear-rack transmission mechanism 2, a hydraulic slide valve 3, a pneumatic piston 4, and a cover 5. A cover 5 is installed on the upper part of the throttle housing 1. A hydraulic slide valve 3 is installed inside one side of the throttle housing 1, and a pneumatic piston 4 is installed inside the other side. A gear-rack transmission mechanism 2 is installed in the middle of the throttle housing 1. The piston rod of the pneumatic piston 4 and the piston rod of the hydraulic slide valve 3 are connected through the gear-rack transmission mechanism 2. The inner cavity of the hydraulic slide valve 3 is connected to the power oil inlet P, and the outer cavity is connected to the power oil outlet S. An oil return port Q is provided below the inner cavity of the hydraulic slide valve 3. The upper chamber of the pneumatic piston 4 is connected to the exhaust port R of the compressor of the steam turbine compressor unit. The power oil inlet is connected to the high-pressure oil outlet of the steam turbine screw compressor unit; the power oil outlet is connected to the high-pressure oil inlet of the main steam valve of the steam turbine screw compressor unit; the oil return port is connected to the oil tank of the steam turbine screw compressor unit.

[0020] The gear-rack transmission mechanism 2 consists of a pneumatic piston rack, a hydraulic slide valve rack, and a gear. The upper end of the piston rod of the pneumatic piston 4 is fixedly connected to the pneumatic piston rack, the upper end of the piston rod of the hydraulic slide valve 3 is fixedly connected to the hydraulic slide valve rack, and the pneumatic piston rack and the hydraulic slide valve rack are connected through gear transmission.

[0021] When the exhaust pressure of the compressor rises to a certain overpressure limit value exceeding the rated pressure for some reason, the compressed air introduced from the exhaust port enters the upper chamber of the piston of the pneumatic cut-off throttle. The piston immediately moves downward rapidly overcoming the spring force, and then drives the slide valve to move upward through the gear and rack, thereby cutting off the high-pressure oil leading to the main steam valve and closing the main steam valve of the steam turbine for emergency shutdown. The high-pressure oil below the slide valve then flows into the oil tank from the bottom oil return port.

[0022] The application of the pneumatic cut-off throttle device of the present invention on the steam turbine screw compressor unit (see Figure 3 ).

Claims

1. A pneumatic cut-off throttle device for the security of a steam turbine compressor unit, comprising a throttle housing and a hydraulic slide valve, characterized in that: A cover is installed on the upper part of the throttle housing; a hydraulic slide valve is installed inside one side of the throttle housing, and a pneumatic piston is installed inside the other side. A gear-rack transmission mechanism is installed in the middle of the throttle housing. The piston rod of the pneumatic piston and the piston rod of the hydraulic slide valve are connected through the gear-rack transmission mechanism; the inner cavity of the hydraulic slide valve is connected to the power oil inlet, and the outer cavity is connected to the power oil outlet; an oil return port is arranged below the inner cavity of the hydraulic slide valve; the upper chamber of the pneumatic piston is connected to the exhaust port of the compressor of the turbocompressor unit; the power oil inlet is connected to the high-pressure oil outlet of the turbocompressor unit; the power oil outlet is connected to the high-pressure oil inlet of the main steam valve of the turbocompressor unit; the oil return port is connected to the oil tank of the turbocompressor unit; when the exhaust pressure of the turbocompressor unit exceeds the rated pressure, compressed air introduced from the exhaust port of the turbocompressor unit enters the upper chamber of the pneumatic piston. The pneumatic piston moves downward against the spring force and then drives the hydraulic slide valve to move upward through the gear-rack transmission mechanism, thereby cutting off the high-pressure oil leading to the main steam valve and closing the main steam valve of the steam turbine for emergency shutdown. The high-pressure oil below the hydraulic slide valve then flows into the oil tank from the bottom oil return port.

2. The pneumatic cut-off throttle device for security of the steam turbine compressor unit according to claim 1, characterized in that: The gear-rack transmission mechanism consists of a pneumatic piston rack, a hydraulic slide valve rack and a gear. The upper end of the piston rod of the pneumatic piston is fixedly connected to the pneumatic piston rack, the upper end of the piston rod of the hydraulic slide valve is fixedly connected to the hydraulic slide valve rack, and the pneumatic piston rack and the hydraulic slide valve rack are connected through gear transmission.

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