ABB valve positioner fail -safe function

ABB valve positioner working principle

(1) When it contains solid suspended matter or viscous fluid and becomes the medium to be adjusted, in order to overcome the resistance of the medium to the movement of the valve stem, abb valve positioner can be used.

(2) It can be used to improve the flow characteristics of the regulating valve.

(3) It is used for occasions where the pressure difference between the two ends of the valve is large. In order to reduce the stroke error and overcome the unbalanced force generated by the liquid on the valve core, the output force of the actuator can be increased by increasing the air source pressure.

(4) Split range adjustment is a process in which two abb valve positioners are used to accept high input signal and low input signal respectively, then one actuator acts at high altitude and the other acts at low range. One regulator controls two actuators to implement split-range control.

(5) In order to increase the output thrust of the actuator, a large-diameter regulating valve can be used.

(6) The reliability and positioning accuracy of the regulating valve can be improved by using an important regulating system with high requirements for regulating quality.

(7) When the distance between the actuator and the regulator is more than 60m, in order to improve the action response speed of the valve and overcome the transmission delay of the control signal, abb valve positioner can be selected.

(8) When the medium to be adjusted is toxic, explosive, flammable, high temperature, high pressure and low temperature, in order to press the packing very tightly to increase the friction between the packing and the valve stem, use abb valve for positioning. The device can prevent external leakage, and can also overcome the time lag.

Brief description of "fail-safe" and "fail-latch" functions of intelligent valve positioners

The arrival of the intelligent age brings great convenience to people in process control. Valve positioner is a model of intelligent instrument, which not only improves the accuracy and sensitivity of valve position control, but also improves the safety factor and enterprise benefit of process control. The specially mentioned safety locking function is a good application case for the ABB brand valve positioner, and its existence is more proof of the arrival of the intelligent valve positioner.

The safety function keeps the valve in the fully closed or fully open position, cutting off the flow source in time.

When the power is turned off or the signal is turned off, the positioner output 1 is decompressed and the pneumatic actuator responds. The spring enables the valve to operate in the prescribed safe position. If it is a dual executor. Output 2 is boosted simultaneously. The safety function makes the valve return to the fully open state in time when the signal is lost, allowing the liquid to enter the storage tube at the maximum flow rate, preventing explosion or melting caused by excessive internal temperature, or keeping the valve in a completely closed state, preventing Excessive heat or corrosive liquids entering the storage tank can cause damage.

For ABB valve positioners, most have self-protection interlocks. The ABB valve positioner can self-lock when the power is off, and the Siemens PS2 can also self-lock or open and close the valve when the power is off. In addition to the above functions, these positioners also accept the input of external interlock signals. While these chain reactions are not millisecond-scale, for many process industries a secondary chain reaction is sufficient. Such as heating furnace fuel valve interlock. At the same time, the millisecond interlocking of the check valve requires high safety level. It should be set separately in the design regulations and is not allowed to be placed together with the control loop. Therefore, it is unrealistic to require the interlocking of the intelligent valve positioner to reach the millisecond level. The fault diagnosis function of Yulin vertical exhaust check valve is an important function of the intelligent valve positioner. In the actual startup or debugging process, various problems will be encountered. How to correctly judge and solve these problems is very important to the normal and safe production of the power plant. For ABB valve positioners, diagnosis of valve leakage, valve packing, valve wear, etc. is a feature provided by most smart positioner manufacturers. However, some manufacturers provide few or no functions, so we must look at the samples and consult the manufacturers when selecting models.

The blocking function locks the valve in the current position, maintaining the quantitative input of the liquid flow.

When the power is turned off or the signal is turned off, the positioner will output 1 (if there is output 2). When locked, the pneumatic actuator holds the valve in its current position. If in the air source. Disconnect actuator depressurization. The existence of the blocking function is that the valve is in the current position after losing the signal, which ensures that a quantitative liquid enters the storage tank, which not only ensures the uncertainty of the liquid level measurement, but also provides sufficient maintenance time for the operator.

If the ABB valve positioner does not have safety and locking functions, it will no longer have the convenience and safety performance brought by intelligence. When the user unit does not use these two functions, it may cause the loss of previous data or equipment damage due to the sudden termination of the signal.

Good sealing is very important for valve selection. After all, the electric butterfly valve is used to adjust the fluid flow in time, and it faces high temperature and high pressure when working. Therefore, if the seal is not good, it will cause liquid leakage. Check valves cannot guarantee accurate flow regulation. The electric butterfly valve has a special sealing system, so it has good sealing performance in the range of ultra-low temperature to high temperature, that is to say, the sealing performance of the electric butterfly valve is not affected by temperature, so what is the durable vertical exhaust check valve? , Electric control valve switch is very convenient. The sealing performance of the electric butterfly valve is very good. The shaft diameter seal of the valve stem is made of graphite. The sealing ring will not be stuck on the butterfly plate of the electric butterfly valve. Therefore, the electric butterfly valve with excellent sealing performance and zero leakage fire safety performance is the first choice of many users.

ABB's intelligent electrical positioner has a wide range of applications and is suitable for single, double-acting, linear and angular stroke actuators.

ABB digital positioner model:

ABB digital positioner TZIDC

ABB digital positioner TZIDC110

ABB digital positioner TZIDC120

ABB digital positioner TZIDC200

ABB digital positioner TZIDC210

ABB digital positioner TZIDC-220

ABB I/P converter TEIP11

ABB Pneumatic and electro-pneumatic positioners AV1/AV2

ABB Pneumatic and electro-pneumatic positioners AV3/AV4

ABB digital positioner EDP300