KOSO valve positioner Broken Down and Solution
The valve positioner is an important Accessories to the pneumatic Regulating valve. It converts the 4-20mA analog signal into the air pressure of the output, thereby completing the action control of the valve actuator. It can realize the reverse control of the regulating valve, so that the regulating valve can achieve best positioning.
We take the EP800 series as an example to tell the fault and processing method of the positioner.
2.1 The input signal of the electrical valve positioner is normal, and there is no corresponding pressure signal
(1) Constant throttling orifice blocked: Because the constant throttling orifice are small, So there are many faults. The main reason is that the instrument compress the humidity of the air in the air pipeline, and the dirt entered with the tube wall or other sources is blocked at the constant throttling orifice. In some sugar factories and starch processing plants, process operation errors or other reasons often occur, so that the maltose or starch milk and other dirt of the process pipeline enters the instrument compressing air pipeline, causing the positioning of the constant pores of the positioner. The solution is also very simple, that is, finding the shredded electrical lacquer cable (copper line) for insertion. When it is almost cleaned, you can also use a large compressed air to blow down. It is worth noting that the positioner generally has an air purifier device, and the usual inspection should be discharged.
(2) The compressed air‘s pressure less or exceed. If the air pressure is too large, the positioner is prone to damage. If it is too small, the regulating valve will not move. The abnormality of compressed air is usually caused by the instrument compression of the air pipeline block and the abnormal air compressor. For dirt and frozen blockage, if there is a problem with the instrumental wind split pipeline of the positioner, just replace the copper pipe and PVC pipe. If it is blocked by the supervisor line, you need to contact the process director to stop and repair it.
2.2 The output pressure of the stroke positioner is slowly changing
(1) The diaphragm of the amplifier in the locator is damaged. The cause of this problem is caused by compressed air into the air, steam, steam and acid -alkali substances or compressed air pressure. Generally speaking, there is no problem with the diaphragm of the amplifier for half a year. Once overheated water and gas enter or compress the air, most of them will reduce the service life of the film. The entry of overheated water and gas is usually caused by the mistakes of the operator. Therefore, we must improve the business ability, proficiency and responsibility of post operators. Excessive pressure is usually caused by air compressor settings and abnormalities, and instrumental maintenance personnel need to be inspected and maintained.
2.3 Positioner is linear is not good. Mainly due to the opening of the magnet, the position of the position and the increasing installation of the feedback mechanism, the improper installation of the spring, and the dirt of the nozzle. The solution is to be installed correctly according to the instructions, and the opening of the opening of 0, 25, 50, 75, and 1005. In addition, dirt and foreign objects in the air purifier should be eliminated in time to avoid the occurrence of linear deviations.
