A pressure reducing valve refers to a valve that reduces the inlet pressure to a required outlet pressure through throttling of the valve disc, and can use the energy of the medium itself to keep the outlet pressure basically unchanged when the inlet pressure and flow rate change.
Depending on the type of valve, the outlet pressure is determined by the pressure regulation setting on the valve or by an external sensor. Pressure reducing valves are commonly used in residential, commercial, institutional and industrial applications.
Pressure reducing valve inspection-appearance quality inspection requirements
Pressure reducing valve surface quality inspection
The pressure reducing valve must not have defects such as cracks, cold shuts, blisters, pores, slag holes, shrinkage porosity and oxidation slag inclusions. Valve surface quality inspection mainly includes inspection of surface gloss, flatness, burrs, scratches, oxide layer, etc. It needs to be carried out in a well-lit environment and using
professional surface inspection tools.
The non-machined surface of the pressure reducing valve should be smooth and flat, and the casting mark should be clear. After cleaning, the pouring and riser should be flush with the surface of the casting.
Pressure reducing valve size and weight inspection
The size of the valve has a direct impact on the valve's opening and closing performance and sealing performance. Therefore, during the valve appearance inspection, the size of the valve needs to be strictly inspected. Dimensional inspection mainly includes inspection of valve diameter, length, height, width, etc. The size and weight deviation of the pressure reducing valve should comply with regulations or according to the drawings or models provided by the purchaser.
Pressure reducing valve marking inspection
The appearance inspection of the pressure reducing valve requires inspection of the valve's logo, which must meet the requirements of the valve product standards. The logo must be clear and not easy to fall off. Check the pressure reducing valve logo. The valve body should have valve body material, nominal pressure, nominal size, melting furnace number, flow direction, and trademark; the nameplate should have applicable media, inlet pressure range, outlet pressure range, and manufacturer name. Model specifications, date of manufacture.
Pressure reducing valve box label color box packaging inspection
Pressure reducing valves need to be packaged before leaving the factory to protect the valves from damage during transportation and storage. The appearance inspection of the pressure reducing valve requires inspection of the valve's box label and color box packaging.
Pressure reducing valve inspection-performance inspection requirements
Pressure reducing valve pressure regulating performance inspection
Within a given pressure regulation range, the outlet pressure should be continuously adjustable between the maximum value and the minimum value, and there should be no obstruction or abnormal vibration.
Pressure reducing valve flow characteristics inspection
When the outlet flow changes, the pressure reducing valve must not have abnormal actions, and the negative deviation value of its outlet pressure: for direct-acting pressure reducing valves, it shall not be greater than 20% of the outlet pressure; for pilot-operated pressure reducing valves, it shall not be greater than 10% of the outlet pressure.
Inspection of pressure characteristics of pressure reducing valve
When the inlet pressure changes, the pressure reducing valve must not have abnormal vibration. Its outlet pressure deviation value: for direct-acting pressure reducing valves, it shall not be greater than 10% of the outlet pressure; for pilot-operated pressure reducing valves, it shall not be greater than 5% of the outlet pressure.
|
Function size DN |
Maximum leakage volume drops (bubbles)/min |
|
≤50 |
5 |
|
65~125 |
12 |
|
≥150 |
20 |
The rising elastic seal of the outlet pressure gauge should be zero metal - the metal seal should not exceed 0.2MPa/min.
continuous operation capability
After continuous operation tests, it can still meet the pressure regulation performance and flow requirements.
Post time: May-21-2024