Gas dispenser for power plants

Abstract

FIELD: mechanical engineering.SUBSTANCE: invention which can be used in gas supply systems of any gas turbine engines or internal combustion engines where precise gas dosing is required. The gas metering device for power plants comprises an explosion-proof radiator housing, a stepper motor and an optical encoder located inside the housing, and an explosion-proof terminal box, a control valve with a shaft and a metering element located inside it. The housing includes a removable cover and seals, and a cylindrical unit with a profiled hole located between bearings is used as a metering element, while the metering element is made on a shaft, and the optical encoder is made with an IP65 protection rating and with a number of rotation angle control points of at least 16,384 points per 1 revolution.EFFECT: simplifying the design and maintainability of a gas dispenser in a repair shop at the site of operation, as well as improving its operational characteristics.4 cl, 3 dwg

Description

[0001] This invention relates to mechanical engineering, specifically to the control of gas supply to the combustion chamber of gas piston (GPE) and gas turbine (GTE) engines operating on gas fuel, and can be used in various mechanisms and machines. Specifically, the Gas Metering System (GMS) can be used to precisely regulate gas supply to the combustion chamber of the AI-20 gas turbine engine during ground operation, and can also be used in gas supply systems of any gas turbine engine or internal combustion engine where precise gas metering is required.

[0002] A large number of solutions are available for regulating gas supply to the engine combustion chamber. These include the control metering unit, a stationary DUS manufactured by JSC "MPO im. I. Rumyantsev," the 816.042 gas metering unit manufactured by PJSC "Volchansk Aggregate Plant," and the GS16 gas metering system from WOODWARD (USA).

[0003] A gas metering device (RU214824, published 11 / 15 / 2022) is known from the prior art, comprising a metering element separating a high-pressure cavity connected to an inlet nozzle and a gas metering cavity connected to the burners of a gas turbine engine, a pusher with a screw pair, a stepper electric motor with a double-sided shaft driving the metering element through the pusher with a screw pair, a feedback sensor for the angular movements of the metering element, the metering element, made in the form of a spring-loaded plate valve mounted on the spherical end of the pusher on the side of the inlet line.

[0004] The disadvantages of this technical solution are the dependence of the design's performance on the condition of the screw pair, which wears out during operation, which can cause backlash during operation, or complete jamming of the pusher, which will lead to the failure of the entire gas dispenser unit.

[0005] A gas dispenser (RU2772165, published 05 / 18 / 2022) is known from the prior art, comprising a metering element with a rod and a hybrid stepper motor connected to this rod, and also an optical position sensor (encoder) installed in the control unit of the stepper motor SPSh20-34100 (the housing of the SPSh20-34100 is made in IP54 design), the metering element, connected to the shaft of the hybrid stepper motor.

[0006] The disadvantage of this technical solution is that the housing of the stepper motor SPSh20-34100 is not explosion-proof, which does not allow certifying the explosion-proof design of the gas dispenser, as well as the low reliability of the incremental optical position sensor (encoder) used in the SPSh20-34100, since during long-term operation, contamination (dust, moisture, etc.) may get into the gaps of the housing with an IP54 protection rating, which will lead to the failure of the entire gas dispenser unit, as well as the lack of absolute positioning of the rotation angle, which also affects the reliability in case of possible temporary shutdowns of the SPSh20-34100 control controller.

[0007] The problem that the claimed invention is aimed at solving is to simplify the design and maintainability of the gas dispenser in the conditions of a repair shop at the place of operation, as well as to improve the operational characteristics.

[0008] The technical result is achieved by creating a gas metering device for power plants with a replaceable metering part, installing an encoder with an increased degree of protection and with a large number of rotation angle control points.

[0009] The technical result is achieved by a gas dispenser for power plants, containing a radiator housing in an explosion-proof design, a stepper motor and an optical encoder placed inside the housing and a terminal box in an explosion-proof design, a control valve, with a shaft and a metering element placed inside it, wherein a cylindrical unit with a profiled hole, placed between bearings, is used as the metering element.

[0010] The invention is further explained by the following drawings:

[0011] Fig. 1. – gas dispenser - sectional view;

[0012] Fig. 2. – control valve - sectional view;

[0013] Fig. 3. – dosing element.

[0014] The gas metering device for power plants includes a control valve 1, an explosion-proof radiator housing 5, a stepper motor 2 and an optical encoder 4 located inside the housing, couplings 3, 7 and a terminal box 6 in an explosion-proof design.

[0015] The control valve includes a shaft 8 located in the valve body 9 and a metering element.

[0016] A cylindrical unit with a profiled hole is used as a metering element in the gas metering device.

[0017] Stepper motor 2 and optical encoder 4 are connected to the control system via electrical communication lines (via a digital interface), which also interact with sensors and actuators installed on the gas turbine unit.

[0018] Via coupling 3, shaft 8 of the control valve is connected to the shaft of stepper motor 2. Shaft 8 is mounted in seat 13 made of polymer material. The metering portion of shaft 8 contains a metering element. Optical encoder 4, which serves as a position sensor for metering element 8, is mechanically connected to the shaft of stepper motor 2 and electrically connected to the control unit.

[0019] Using two flanges 10, the gas dispenser is connected to the pipeline through which gas enters the combustion chamber of the gas turbine unit.

[0020] To prevent gas leakage, a sophisticated shaft sealing system 14 is installed in cover 16, which includes several O-ring seals, an end seal, and a pressure spring to improve tightness.

[0021] To increase the service life of the gas metering valve's sealing system, its metering element is installed between bearing 12 and bearing 11. Compared to metering valves with only one bearing, installing the metering element shaft between two bearings increases the rigidity of the shaft installation and leads to significantly less bending deformation of the shaft and movement perpendicular to the shaft axis during operation, which in turn has a lesser destructive effect on its sealing system.

[0022] To improve the reliability and accuracy of the gas metering device, its metering element is designed in the form of a cylinder with a profiled hole 15. The area of ​​the profiled hole 15 is calculated based on the characteristics of a specific engine and, in the main working area, has a linear flow characteristic depending on the angle of rotation of the metering element 8.

[0023] Using an optical encoder with an increased IP65 protection rating and a rotation angle control point count of at least 16,384 points per revolution instead of a revolver or encoder as a metering element position sensor allows for increased positioning accuracy of the metering element 8 and, accordingly, increased accuracy of gas metering into the engine combustion chamber.

[0024] The cylindrical shape of the metering element allows for axial assembly of the valve, allowing for the installation of bearing 11 at the bottom of the valve. This positions the cylinder between bearings 11 and 12, increasing reliability and reducing wear on bushing 13, thereby improving performance.

[0025] The rotor of stepper motor 2 contains rare-earth magnets. Due to its design, it requires significantly less current to provide the same holding torque as a synchronous stepper motor. Therefore, the stepper motor runs cooler, which improves both its own reliability and that of the control unit. This also reduces the power requirements of the uninterruptible power supply systems for the entire power plant, improving operational performance.

[0026] In a particular case, the connection of the control valve to the pipeline can be either flanged or may contain welded or threaded connections.

[0027] The gas dispenser is operated by the electrical installation controller by supplying a control signal to the terminals of stepper motor 2, while receiving feedback from the shaft rotation angle sensor (encoder) to ensure corrective control when the stepper motor rotor slips, when performing movement, and during microstep control.

[0028] Under the influence of the control signal, stepper motor 2 sets the metering valve to the position required to maintain the required value of the gas turbine unit parameter, which is determined by the control system.

[0029] The rotor of the dosing valve has an angle of rotation from 0 to 92 degrees, which is limited by limit switches, while the time of its rotation from one extreme position to another will not exceed 0.1 seconds.

[0030] Implementation of the invention

[0031] To replace the cylindrical unit with the metering element, remove cover 16 from the gas metering unit, then dismantle seals 14, and then bearing 12. Next, pull out the metering element in the direction of cover 16 and remove bearing 11 with a puller. Assembling the metering unit occurs in the reverse order.

[0032] The use of a stepper motor is the most advanced and reliable solution for gas dispenser designs, where the motor shaft rotation angle is limited to a quarter turn. In this case, the stepper motor requires less power than other types of electric motors, allowing for optimization of the specific needs of the equipment where the gas dispenser is used.

[0033] Using a cylindrical unit with a profiled hole simplifies the readjustment of the dispenser according to its flow characteristics, and also makes it easier to carry out repairs in operating conditions, reduces the cost of manufacturing the gas dispenser and improves its performance characteristics.

[0034] The cylindrical metering element simplifies production compared to the ball metering element, and also simplifies the assembly and maintenance of the crane, since only a metalworking tool is used without special equipment, and it also becomes possible to dismantle the metering element through the top cover 16 after dismantling the shaft seals 14.

[0035] The presented design of the gas dispenser is repairable, which improves its performance characteristics and reliability.

Claims

1. A gas metering device for power plants, comprising an explosion-proof radiator housing, a stepper motor and an optical encoder placed inside the housing, and an explosion-proof terminal box, a control valve with a shaft and a metering element placed inside it, characterized in that the housing includes a cover made with the possibility of removal and seals, and a cylindrical unit with a profiled hole placed between bearings is used as the metering element, wherein the metering element is made on the shaft, and the optical encoder is made with a protection rating of IP65 and with a number of rotation angle control points of at least 16,384 points per 1 revolution.

2. A gas metering device for power plants according to paragraph 1, characterized in that it contains a stepper motor with a rotor rotation control unit attached to it.

3. A gas metering device for power plants according to paragraph 1, characterized in that a developed shaft sealing system is installed in the cover, including several ring seals, an end seal and a pressure spring.

4. A gas metering device for power plants according to paragraph 1, characterized in that the control valve is equipped with a flange or thread for connection to a pipeline.

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