DZW Electric Valve Actuator
The multi-turn explosion-proof electric valve actuator, also known as the ZB electric valve actuator, is specially designed and manufactured for the conditions of use in coal mines. ZB type is suitable for valves with linear motion of the valve plate, such as gate valves, globe valves, water gates, etc.; after adding a two-stage deceleration worm gear box, it can also be used for valves with 90-degree rotation of the valve plate, such as butterfly valves, dampers, etc. The ZB type electric valve actuator (hereinafter referred to as the electric actuator) must be matched with the corresponding special flameproof electric valve actuator control box before it can be used; the control box can also be connected with the DCS system to realize automatic control. The performance of the electric actuator conforms to the company's corporate standard Q/3204CN001-2011 "Technical Conditions for Electric Devices of Mine Isolation Valves", GB3836.1-2010 "Explosive Atmosphere Part 1: Requirements for Equipment", GB3836.2-2010 "Explosive Atmosphere Environmental Part 2: Equipment protected by flameproof type "d"". The explosion-proof mark is Exd I Mb.
Technical parameters
Power supply: conventional, three-phase 380V (50Hz) special,
three-phase 660V, 415V (50Hz, 60Hz)
Single phase 220V, 110V (50Hz, 60Hz)
Working environment:
Ambient temperature: -20~+60℃ (special order -40~+80℃)
Relative humidity: <95% (at 25C)
Protection type, the outdoor type is used in places without flammable, explosive and non-corrosive media. Explosion-proof products include dI and dIBT4. dI is suitable for non-excavation working faces in coal mines, and dIBT4 is used in factories, and is suitable for explosive gas mixtures whose environment is Group IIA and IIB T1~T4. Protection level: IP55 (special order IP65, IP67)
Duty cycle: short time 10 minutes (special order 30 minutes).
Models
Structures
ZB type electric actuator is composed of motor, deceleration mechanism, torque control mechanism, stroke control mechanism, opening indicating mechanism, hand-electric switching mechanism, hand wheel and electrical parts. Its transmission principle is shown in the figure
Motor: Explosion-proof three-phase asynchronous motor for electric valve actuator with MA certificate.
Reduction mechanism: It consists of a pair of spur gears and a worm gear pair of two-stage transmission; the power of the motor is transmitted to the output shaft through the reduction mechanism
5.3 Control mechanism: The structure is shown in Fig. When the output shaft is subjected to a certain torque, the worm produces axial displacement in addition to rotation, driving the bellcrank, which drives the bracket through the bumper to generate angular displacement; when the torque on the output shaft increases to the set torque, Then the displacement generated by the bracket makes the torque switch act, thereby cutting off the power supply of the motor and stopping the motor. In this way, the control of the output torque of the electric device is realized, and the purpose of protecting the electric valve is achieved.
Travel control mechanism:
It adopts the principle of decimal counter, also known as counter, with high control precision. The structure is shown in the figure below. Its working principle is: a pair of large and small bevel gears in the gearbox drive the intermediate transmission pinion, and then drive the stroke control mechanism to work. If the stroke control mechanism has been adjusted according to the opening and closing position of the valve, when the stroke control mechanism rotates to the pre-adjusted position (number of turns) with the output shaft, the cam will rotate towards the stroke switch, forcing the stroke switch to act and cut off the motor. Power supply, the motor stops, so as to realize the control of the stroke (number of revolutions) of the electric actuator.
Opening indicating mechanism: The structure is shown in the figure below. The input gear is driven by the unit gear of the counter. After deceleration, the indicator plate rotates simultaneously with the valve opening and closing process to indicate the closing value of the valve. The potentiometer shaft and the indicator plate rotate synchronously for remote opening indication. The number of revolutions can be changed by moving the number of revolutions adjustment gear. There is a micro switch and a cam inside the opening indicating mechanism. When the electric device is running, the rotating cam periodically makes the micro switch act, and its frequency is one or one action per revolution of the output shaft, which can be used for flashing signals, etc.
Hand-electric switching: It is a semi-automatic switch, you need to pull the handle to switch when manual, and it will run automatically when the manual state changes to electric. Its structure is shown in Figure 7. It is composed of handles, switching parts, upright rods, clutches, pressing materials, etc. When handwheel operation is required, push the handle to the manual direction, and the switching piece will raise the clutch and compress the compression spring. When the handle is pushed to a certain position, the clutch will disengage from the worm wheel and engage with the hand wheel. At the same time, the upright rod stands upright on the end face of the worm wheel under the action of the spring, supporting the clutch from falling. After the switching is completed, the handle can be released and the hand wheel can be used for operation. When electric operation is required, the motor will drive the worm wheel to rotate, and the upright rod supported on the end face of the worm wheel will fall down. Under the action of the pressure spring, the clutch will quickly move to the direction of the worm wheel, mesh with the worm wheel, and disengage from the hand wheel at the same time, automatically realizing manual operation. transition to electric state.
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