Self-operated pressure regulating valve does not need external energy, uses the energy of the medium to be adjusted as the power source, introduces the actuator to control the position of the valve core, changes the pressure difference and flow at both ends, and stabilizes the pressure before the valve (or after the valve). It has the advantages of sensitive action, good sealing performance and small fluctuation of pressure set point.
Self-operated pressure regulating valve installation
1. Before installation, it is necessary to check whether the product model, designation number and specifications are consistent, and check whether the parts of the whole machine are damaged or loose.
2. Before installation, the pipeline should be cleaned, and there should be enough straight pipe sections at the entrance of the valve, and a filter should be provided. The flange connection between the valve body and the pipeline should pay attention to the coaxiality.
3. Before installing the shut-off valve, the pipeline should be thoroughly cleaned.
4. The installation site should take into account the safety of personnel and equipment, which is not only easy to operate, but also conducive to disassembly and maintenance.
5. The valve should be installed upright and vertical on the horizontal pipeline. If necessary, it can be installed obliquely. Try to avoid horizontal installation. When the valve has a large weight or vibration, a support frame should be used.
6. The flow direction of the medium should be consistent with the arrow on the valve body. The air source should be dry and free of oil. The valve should be used in places where the ambient temperature is -20~55℃.
Maintenance of self-operated pressure regulating valve
1. Cleaning the valve: For cleaning general media, just wash it with water. However, for cleaning the medium that is harmful to health, we must first understand its properties, and then choose the corresponding cleaning method.
2. Disassembly of the valve: Remove the rusted parts on the exposed surface first, but before removing the rust, protect the machined surface of the valve seat, valve core, valve stem and push rod and other precision parts. Special tools should be used when disassembling the valve seat.
3. Valve seat: The sealing surface has small rust spots and wear, which can be carried out by mechanical processing. If the damage is serious, it must be replaced. However, regardless of the repaired or replaced hard sealing surface, it must be ground.
4. Valve stem: the surface is damaged and can only be replaced.
5. Damage to the push rod, guide and sealing surfaces: the reverse-acting actuator must be replaced, while the positive-acting actuator can be used after proper repair.
6. Compression spring: If there are defects such as cracks that affect the strength, it must be replaced.
7. Vulnerable parts: packing, sealing gasket and O-ring, all of them should be replaced with new ones every time they are overhauled. The valve core and diaphragm must be checked for cracks, aging and corrosion marks that may occur in the future. According to the inspection results, it is decided whether to replace them, but the service life of the diaphragm is generally 2-3 years longer.
8. Pay attention to the centering of the valve assembly, the bolts should be tightened diagonally, and the sliding parts should be lubricated. After assembly, it should be debugged according to the product factory test items and methods, and during this period, the packing pressing force and the closing position of the valve core can be adjusted accurately.