Control Valves

All fittings originating in the assembly, must comply with installation drawings and technical specifications (TS) state (GOST) and industry (OST) standards. Fittings prior to installation carefully inspect and install: line fitting the project requirements, availability of technical documentation for production plants, the quality of housing (cracks, cavities, chips and other defects), the quality of the sealing surfaces (no signs of corrosion, scratches, sinks), the ability of a free and smooth movement of the spindle. At revision valves perform the following work: cleaning, re-entry and inspection of all parts, lubrication running gear check sealing surfaces, assembly fixture with the installation of gaskets, gasket seal and check the movement of the chassis, the hydraulic test of strength and density. Work on the revision reinforcement is carried out in a special room equipped with devices for the audit and machines for defects and test fixtures. Stop, control and relief valves shall be subjected to Control revision. Rings and disks valves and plugs migratory cranes should be lapped. Risks to the ends of the squares of cork-through valves and spindles adjusting valves must comply with the direction passage of the medium. Gaskets in valves, actuators and valves should be tightly packed and sealed.

Seal material gate valves should be checked for compliance with the transported medium. Sealing the surface gates lap on the machines of various designs, or manually by rolling the spindle by turning the valve with a gate in the walls of the sealing body. Gates and taps lap, then rotate the spool, cap, or a special lap for sealing surfaces of the gate. You can manually rotate the lapping, grinding or drilling machine. In valves after long-term storage gland packing should be replaced by a new one. Padding placed individual rings.

Laying of a spiral is not allowed. The height of breakdowns in the nest packing should be such that the jack is inserted into a glass seal could tighten if necessary. For valves up to 100 mm possible tightening gland is 20 mm, with a larger diameter fittings – 30mm. Gland packing for valves, actuators and valves are chosen depending on operating environment. If the working medium is water temperature to 100 C, it is recommended asbestos, talc braided or fluoroplastic packing. Armature valve type that is installed on the pipelines of hot water temperature of the hot water temperature to 140 C, must be fitting seal of heat-resistant rubber or fiber, and water temperature to 180 C and a pair of low pressure – from the fiber. Valves, Plug valves and valve bushing received in the assembly or directly to the installation of heating, hot and cold water, have a hydraulic pressure of 1 MPa for 2 min or air 0.15 MPa within 0.5 min. The pressure drop on the pressure gauge is not allowed. The test should be conducted in compliance with safety measures security. When a pneumatic test of piping parts and assemblies for the detection of defects is immersed in a water bath. Eliminate defects during testing jelly, chasing or pulling threaded connections are not allowed. At the assembly plants using special stands for a single test or group fittings. During the tests comply with the necessary safety precautions.