Working principle of steam pressure reducing valve——HERO VALVE

Brief introduction of steam pressure reducing valve products:

      The steam pressure reducing valve is divided into manual, self-operated, pneumatic, and electric forms according to the driving method: according to different working conditions, different pressure reducing valve products are used, which are mainly used for reducing the pressure of the outlet pressure of the steam pipeline.

   Reducing valve is a valve that can reduce the inlet pressure to a certain required outlet pressure by adjusting and rely on the energy of the medium itself to keep the outlet pressure stable automatically. From the point of view of fluid mechanics, a pressure reducing valve is a throttling element whose local resistance can be changed, that is, by changing the throttling area, the flow velocity and the kinetic energy of the fluid are changed, causing different pressure losses, thereby achieving the purpose of decompression. Then rely on the adjustment of the control and adjustment system to balance the fluctuation of the pressure behind the valve with the spring force, so that the pressure behind the valve remains constant within a certain error range.

   a. The manual steam pressure reducing valve belongs to the pilot piston type structure; it needs to manually twist the screw to adjust the pressure reducing size, which is composed of the main valve and the pilot valve. The main valve is mainly composed of valve seat, main valve disc, piston, cylinder liner, spring and other parts. Set the outlet pressure by adjusting the spring pressure, use the diaphragm to sense the change of the outlet pressure, and adjust the size of the overflow area of the throttle part of the main valve through the pilot valve opening and closing to drive the piston to achieve the pressure reducing and regulating function; but the pressure in front of the valve In the case of fluctuations, the effect of voltage regulation is limited.

   b. The self-operated steam pressure reducing valve is a direct-acting structure: it does not require any external energy to drive, and uses the medium in the pipeline as energy to achieve regulation, decompression, and voltage stabilization. Convenient and energy-saving, quick opening flow characteristics, sensitive action, good sealing performance, self-operated main valve is composed of detection catheter, membrane head, regulating valve, condenser, and valve after the valve components, when the steam enters the membrane head of the actuator through the condenser, The force acting on the diaphragm increases, compressing the spring reduces the opening of the spool to the set value, otherwise the pressure increases. After performing the action of the membrane head, the pressure reducing valve is maintained at an appropriate opening degree to ensure that the required set pressure is stable.

   c. Pneumatic steam pressure reducing valve is composed of actuator, valve body and positioner: it uses compressed air as power source, and realizes proportional pressure reduction through triple parts, actuator and positioner, with compact structure, high temperature resistance and light weight , Sensitive action, large valve capacity, accurate flow characteristics, easy disassembly and assembly, etc. It can realize local control and remote control display. The decompression and voltage stabilization can be freely set according to the parameters. No matter how the pipeline pressure fluctuates, the decompression and stabilization effect is very good. It is especially suitable for large pressure difference and large allowable leakage. Not very clean media occasions.

   d. The electric steam pressure reducing valve belongs to the intelligent type. The valve body is divided into single seat, sleeve, double seat, cage and other structures. It is suitable for various working conditions, regardless of small pressure difference, micro pressure, large pressure difference, High temperature and high pressure can meet the requirements. It is an ideal decompression device with high precision and is widely used in automatic control systems.

    The electronic actuator cooperates with the regulator or PLC system to realize local display, or remote control to achieve decompression and voltage stabilization. The electric steam decompression valve uses a pressure-balanced valve flap, and the remote control and automatic control are realized by adjusting the pressure of the valve flap. When the pressure sensor detects that the valve pressure indicates an increase, the valve opening of the pressure-reducing valve decreases; when the pressure sensor detects that the pressure decreases, the opening of the pressure-reducing valve increases to meet the control requirements.

Basic characteristics of electric steam pressure reducing valve actuator:

When this series of steam pressure reducing valve actuators are used as actuators for regulating valves, they almost have all kinds of action conversion functions required by the regulating valves themselves, as well as valve opening signal functions and manual functions.

1. The actuator is designed with a servo system (no additional servo amplifier is required), and only needs to be connected to DC4 ~ 20m A (or DC1 ~ 5V) signal and corresponding power supply to work. Built-in wiring terminals, wiring is extremely simple and convenient. 2. The key component of the actuator-the controller, adopts the most advanced hybrid integrated circuit, sealed with resin and cast, the shape of the box is small, the volume is small, and the reliability is high.

3. The feedback detection of the driving quantity adopts a high-performance conductive plastic potentiometer with a resolution <0.4%.

4. With self-diagnosis function, when a fault occurs, the indicator light on the controller will immediately give an indication signal.

5. When the state selection switch can be used to set the off signal, (the spool is fully open, fully closed or self-locking.)

6. Can be set with the state selection switch (forward and reverse action.)

7. Use the state selection switch to set the input signal to (DC4 ~ 20m A or DC1 ~ 5V.)

8. It is easy to adjust the work zero point (start point) and stroke (end point).

9. When the power is suddenly cut off, it can ensure the spool self-locking.

10. The use of synchronous belt rotation effectively reduces noise.

11. Delay protection function, can perform status self-locking at rated load, can start protection immediately when a fault occurs, and can cancel the delay protection in reverse operation.

The basic features of the electric steam pressure reducing valve intelligent digital display actuator:

1. Adopt linear photoelectric isolation technology, regulating signal and feedback signal are isolated from each other, without any influence on the host computer system.

2. Adopt a new type of switching power supply to make the input voltage range of the working power supply suitable for it wider, while saving its own power consumption.

3. Adopt onsite setting mode, adjust the input and output range by selecting different parameter control modes for the configuration of the controller working unit.

4. Double-row four-digit photoelectric digital tube is used to track and display the input adjustment signal and feedback output signal (percentage value), and the working state is indicated by the light-emitting diode. The working status of the actuator is clear at a glance.

5. Disturbance-free switching between automatic and manual. The actuator will alarm when the fault occurs and automatically cut off the motor power supply. Work can be resumed only after troubleshooting or re-powering on.

6. Adjustable travel electric limit, and display {-dx-} when the input adjustment signal is lost and keep the original position according to the working mode preset by the user, fully open or fully closed.

7. A limit switch can be added to access the forced limit. The access should be outside the range of the valve position and act as a protective function against accidental faults. The protection will be notified in about three minutes (that is, the alarm light is on) to eliminate the fault Power on the heavy punch to resume work. Double protection electric actuators operate more safely.

   Digital display type intelligent electric steam pressure reducing valve controller is a new generation controller which is based on the original intelligent controller and integrates the internationally popular advanced single-chip micro-processing system design. It has the characteristics of reliable performance, perfect function, strong applicability, simple commissioning and convenient operation. It is suitable for places where 4-20mA current signal controls valves, such as power generation, chemical industry, metallurgy, light industry, boiler and other industries.

——HERO VALVE