Turbine quick-shut valve

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1. Overview 1.1 Explanation The quick-shut control device is a combination of the turbine safety system and the control system. It combines the individual components that were part of the original system together. In this way, the drawbacks of numerous pipelines and complex installation are overcome; moreover, monitoring difficulties as well as accidents such as oil leaks and fires are avoided during operation, thereby enhancing the reliability and safety of turbine operation. The quick-shut control device enables normal startup and shutdown of the turbine, electric and manual emergency shutdown, online testing of the quick-shut valve, and automatic engagement of the emergency stop device. To enhance safety, the quick-shut-off control device is also equipped with a redundant electric emergency stop system. The above functions are implemented by the basic module, redundant module, and startup module respectively. 1.2 Technical Parameters 1.2.1 Hydraulic Parameters Oil source pressure: 0.8 MPa (0.6–1.2 MPa). Working medium: Turbine oil, grades 32# and 46#. Filtration accuracy: ≤40 μm. Liquid temperature: 10–70°C. 1.2.2 Electrical Parameters Power supply voltage: 24 VDC (1±10%). 1.2.3 Ambient temperature: –20–80°C. 1.2.4 Protection type: IP65 (non-explosion-proof); EExd11cT4 (explosion-proof). The user must specify the protection type when placing an order. 2. Functions and Principles 2.1 Basic Module 2.1.1 Composition Manual shutdown valve (2274) Solenoid valve (2225) Shutdown relief valve (2030) Control oil switching valve (2050) Quick-shut valve online testing valve (1845) 2.1.2 Functions Manual emergency shutdown Electric emergency shutdown Online testing of the quick-shut valve 2.1.3 Principle of operation High-pressure oil enters the basic module from “P”, where it is divided into five streams within the module’s housing. The first path enters the shutdown unloading valve (2030) via the manual shutdown valve (2274) and solenoid valve (2225), overcoming the spring force to keep the valve in a closed state. Under normal operation, the quick-shut oil leading to the shutdown unloading valve does not leak. The quick-shut oil is introduced through the internal pipelines of the redundant module. The second stream of oil passes through the regulating oil switch valve (2050) to become regulating control oil, which then enters the start-up module via the internal pipelines of the redundant module to serve as the fuel for the electro-hydraulic converter. The third route leads to the quick-close valve online test valve (1845) for testing the mobility of the quick-close valve piston. The fourth route leads to the redundancy module and the start-up module, serving as the high-pressure oil source for these two modules. The fifth route leads from “G1” and is used for emergency protection devices. Usually, when the emergency relief device is supplied with oil directly from the high-pressure oil source, at this time “G1” is blocked. 2.1.3.1 Emergency shutdown trip: When the handle of the emergency protection device (2210) in the manual control system is turned, or when the emergency shutdown valve trips, or when the axial displacement reaches an unacceptable level, the oil inlet of the emergency protection device (2210) is sealed off. At this point, the fast-shut oil inlet and the return oil inlet are connected in a ‘T’ configuration, allowing the fast-shut oil to be discharged into the oil tank, thereby causing the fast-shut valve to close quickly. At the same time, the regulating oil switch valve (2050) in the quick-shut control device operates to cut off the regulating oil supply; the regulating oil is discharged into the fuel tank, causing the regulating steam valve to close rapidly. 2.1.3.2 Manual emergency shutdown: Operate the manual shutdown valve (2274) to connect the control oil to the return oil; the relief valve (2030) opens rapidly due to the drop in control oil pressure. At this point, the quick-shut oil is connected to the return oil, and the drop in pressure of the quick-shut oil causes the quick-shut valve to close quickly. At the same time, the control oil switching valve (2050) operates to cut off the control oil supply, causing the control oil to be discharged into the tank and thus enabling the control steam valve to close rapidly. 2.1.3.3 Electric emergency stop solenoid valve (2225) receives a signal power supply (manual or remote automatic), and can be designed to be in an open (NO) state or a closed (NC) state according to user requirements. In the normally open (NO) state, the solenoid valve is not energized; high-pressure oil passes through the solenoid valve to the piston of the shutdown unloading valve (2030), and the oil pressure overcomes the spring force to keep the valve in a closed position. When the power signal is activated, the solenoid valve operates and cuts off the control oil supply to the shutdown relief valve (2030). At this point, the control oil is connected to the return oil, the relief valve opens, the quick-shut oil releases pressure, and the quick-shut valve closes rapidly. At the same time, the control oil switch valve (2050) operates to cut off the control oil supply, causing the control oil to be discharged into the tank and thus enabling the control steam valve to close rapidly. In the normally closed (NC) state, the solenoid valve is energized, and high-pressure oil flows through the solenoid valve to the piston of the shutdown unloading valve (2030); the oil pressure overcomes the spring force, keeping the valve in a closed position. When the power supply signal is cut off, the solenoid valve activates and cuts off the control oil supply to the shutdown unloading valve (2030). At this point, the control oil is connected to the return oil. The unloading valve opens, allowing the quick-shut oil to release pressure, after which the quick-shut valve closes rapidly. At the same time, the control oil switch valve (2050) operates to cut off the control oil supply, causing the control oil to be discharged into the tank and thus enabling the control steam valve to close rapidly. 2.1.3.4 Online test of the quick shut-off valve: The valve used for the online test of the quick shut-off valve (1845) is a three-position valve; when it is not in use, its spool is in the middle position. When the handwheel of the test valve (1845) for the quick-close valve is rotated, the test oil flows to the “H” interface of the quick-close valve via the “H1 or H2” interfaces. The oil pressure exerts a force on the test piston, which in turn pushes the valve stem piston–spring module to move a certain distance in the closing direction. Then, by rotating the handwheel of the test valve (1845) in the opposite direction, the valve returns to its middle position; the oil from the test piston is connected to the return oil flow, and at this point the quick-close valve returns to its normal operating position. During the online testing of the quick-shut valves, rotate the test valve handwheel counterclockwise to allow oil to flow into port “H1” in order to check one quick-shut valve; rotate the test valve handwheel clockwise to allow oil to flow into port “H2” to check the other quick-shut valve. When the user has only one quick-shut valve, one of the interfaces can be selected. 2.2 Redundant Module 2.2.1 Components Solenoid valve (2226) Shutdown relief valve (2040) 2.2.2 Function Electric emergency shutdown 2.2.3 Principle of operation The high-pressure oil that enters the redundant module is supplied from inside the basic module. High-pressure oil enters the shutdown unloading valve (2040) via the solenoid valve (2226), overcoming the spring force to keep the valve in a closed state. During normal operation, the quick-shut oil leading to the shutdown unloading valve does not leak. Quick-shut oil is introduced by the start-up module. During electric emergency shutdown, the solenoid valve (2226) receives a signal power supply (manual or remote automatic). It can be designed to be in the normally open (NO) state or the normally closed (NC) state according to user requirements. In the normally open (NO) state, the solenoid valve is not energized; high-pressure oil flows through the solenoid valve to the piston of the shutdown unloading valve (2040), and the oil pressure overcomes the spring force to keep the valve in a closed position. When the power signal is activated, the solenoid valve operates to cut off the control oil supply to the shutdown unloading valve (2040). At this point, the control oil is connected to the return oil, the unloading valve opens, the quick-shut oil releases pressure, and the quick-shut valve closes rapidly. At the same time, the regulating oil switch valve (2050) in the basic module operates to cut off the regulating oil supply, causing the regulating oil to be discharged into the tank and thus enabling the regulating steam valve to close rapidly. In the normally closed (NC) state, the solenoid valve is energized, and high-pressure oil flows through the solenoid valve to the piston of the shutdown relief valve (2040). The oil pressure overcomes the spring force, keeping the valve in a closed position. When the power supply signal is interrupted, the solenoid valve acts to cut off the control oil supply to the shutdown relief valve (2040); at this point, the control oil is connected to the return oil, the relief valve opens, pressure is released through the quick-shut valve, and the quick-shut valve closes rapidly. At the same time, the regulating oil switch valve (2050) in the basic module operates to cut off the regulating oil supply, causing the regulating oil to be discharged into the tank and thus enabling the regulating steam valve to close rapidly. 2.3 Starting Module (Manual) 2.3.1 Composition: Starting valve (1839), Shut-off valve (1830), Electro-hydraulic converter (1742), Check damper valve (5600). 2.3.2 Function: Normal start-up and shutdown of the turbine; during an emergency shutdown of the turbine, the quick-shut oil is used to rapidly relieve pressure. Converts the control electrical signal of the governor into secondary oil pressure. Automatic hooking of emergency protection device 2.3.3 Principle of operation: The high-pressure oil that enters the activation module is supplied by the pipelines within the redundant module. The high-pressure oil is converted into start-up oil via the start valve (1839), and this start-up oil connects to the upper chamber of the quick-close valve piston through interface “F”. The oil from the emergency relief device enters via interface “G2”, and flows into the lower chamber of the quick-close valve piston disk through the shut-off valve (1830). 2.3.3.1 Starting (manual) 2.3.3.1.1 Creating starting oil The start valve (1839) is a two-position valve. In the shutdown state, the start valve is in a position that connects the start oil circuit to the return oil line, preventing the start oil from being established. At startup, rotate the start valve handwheel clockwise; under the force of the spring, the start valve moves the slide valve upward to another position. At this point, high-pressure oil passes through the start valve as start oil and flows from the “F” port to the upper chamber of the quick-close valve piston, pushing the piston of the quick-close valve against the piston disc. Simultaneously, oil is sent from the “M” port to the emergency safety device to engage it. When this function is not in use, the “M” port can be blocked. 2.3.3.1.2 The quick-shut oil shut-off valve (1830) is a two-position valve. When the machine is shut down, keep the shut-off valve (1830) in a position that connects the quick-shut oil circuit to the return oil line, so that quick-shut oil cannot be established. Once the starting oil pressure is established, rotate the handwheel of the shut-off valve (1830) counterclockwise, and the spool moves upward to another position under the force of the spring. At this point, the quick-shut oil circuit is connected to the “G2” oil circuit, and the quick-shut oil is established. The quick-shut oil is supplied to the lower chamber of the quick-shut valve piston from the “E” port. 2.3.3.1.3 Opening the quick-shut valve: After the quick-shut oil is established, slowly rotate the handwheel of the start valve (1839) counterclockwise to connect the start oil with the return oil. The start oil then returns to the oil tank through the adjustable flow orifice (which is located on the intermediate plate), causing the pressure of the start oil to drop and the quick-shut valve to open gradually. The opening time of the quick-close valve can be adjusted by regulating the opening degree of the throttle orifice through the control valve (5700). 2.3.3.2 Shutdown (manual) The shutdown is carried out by operating the shut-off valve (1830). Rotate the shut-off valve handwheel clockwise to connect the quick-shut oil to the return oil; as a result, the pressure of the quick-shut oil drops, and the shut-off valve closes automatically under the force of the spring. Closing the valve restores it to the shutdown state. At the same time, the start valve (1839) is also in the shut-off state. The shutdown state and operating state of the start valve (1839) are the same. 2.3.3.3 Instructions 2.3.3.3.1 Installation of the electro-hydraulic converter: The electro-hydraulic converter is fixed as an external device on the intermediate plate of the start-up module, with both the supply and return oil lines being internal pipelines. 2.3.3.3.2 Principle of operation of the electro-hydraulic converter: The electro-hydraulic converter converts the control oil coming from the control switch valve (2050) into secondary oil at a pressure of 0.15 – 0.45 MPa; this secondary oil is supplied to the throttle via interface C. For more information on the working principle of the electro-hydraulic converter, please refer to the “User Manual for Electro-Hydraulic Converters”. ) 2.3.3.3.3 One-way damping valve: The one-way throttle valve (5600) is fixed on the intermediate plate of the start-up module; the secondary oil flows through this one-way throttle valve from interface C, via external pipelines, to the throttle valve. When the secondary oil flows in the forward direction, the flow rate can be adjusted by turning the knob of the one-way throttle valve, allowing this valve to function as a throttle. This helps to reduce pressure fluctuations or oscillations in the secondary oil circuit, thereby preventing such fluctuations from reaching the throttle slide valve and affecting its proper operation. When the secondary oil flows in the reverse direction, the one-way throttle valve acts as a check valve, accelerating the descent of the secondary oil. 3. Installation and Testing 3.1 Installation The installation of the quick-shut control device is carried out based on the unit control system diagram, the schematic diagram of the quick-shut control device, and its six-view drawings. The six-view diagram provides the three-dimensional installation dimensions of each oil port. The part numbers and interfaces of the three patterns correspond to each other one-to-one. 3.2 Testing Before the turbine is put into operation, the quick-shut control device should undergo on-site testing. For the test items, refer to the test report section in the manufacturer’s certificate of conformity. The test methods can be referred to the description of functions and principles in this manual, and test records should be kept during testing. 4. Random Data and Precautions 4.1 Random Data: Six-view diagram of the quick-shut control device, schematic diagram, and instruction manual. 4.2 Precautions: To prevent contamination of the quick-shut control device, it must be disconnected from the oil circuit during oil circulation; instead, the random oil circulation tool should be used for circulation. Only after ensuring the oil is clean can the oil source be connected to the device’s piping. 5. Fault Analysis and Troubleshooting 5.1 Oil leakage at the joint interface Oil leakage at the joint interface is mainly caused by the rupture of the O-ring in that area; inspect the O-ring in the leaking section and replace it if it is damaged. 5.2 The quick-shut oil cannot be removed. 5.2.1 Check the shutdown solenoid valves: Verify whether the shutdown solenoid valves (2225, 2226) are functioning properly; if not, replace the solenoid valves. 5.2.1 Check the shutdown unloading valves (2030), (2040) and the control switch valves (2050). The cleanliness of the oil supply can cause sticking in these valves; if sticking occurs,