Valve installation requirements
Hebei Zhenchen believes that the quality of valve installation will directly affect the future use of the valve. Therefore, construction units and production units should pay great attention to it. The installation of the valve should be carried out in accordance with the valve instruction manual and relevant regulations. During the construction process, careful inspection and careful construction are required. Before installing the valve, the pressure test should be passed before installation. Carefully check whether the specifications and models of the valve are consistent with the drawings, check whether all parts of the valve are intact, whether the opening and closing valve can rotate freely, whether the sealing surface is damaged, etc. After confirmation, You are ready to install. When installing the valve, the optimal distance between the operating mechanism of the valve and the operating floor is about 1.2m, which should be at the same level as the chest. When the center of the valve and the handwheel are more than 1.8m away from the operating ground, an operating platform should be set up for valves and safety valves that are operated more frequently. For pipelines with many valves, the valves should be concentrated on the platform as much as possible to facilitate operation. For individual valves that exceed 1.8m and are not frequently operated, equipment such as sprockets, extension rods, movable platforms, and movable ladders can be used. When the valve is installed below the operating surface, an extension rod should be installed, and an underground well should be installed for the floor valve. For safety reasons, the underground well should be covered.
The valve stem of a valve on a horizontal pipeline is best installed vertically upward. It is not advisable to install the valve stem downward. The valve stem is installed downward, which is inconvenient to operate and maintain. It is also prone to corrosion and accidents. Do not install floor-standing valves at an angle to avoid inconvenient operation. Valves on side-by-side pipelines should have space for operation, maintenance, and disassembly and assembly. The clear distance between their handwheels should not be less than 100mm. If the pipe distance is narrow, the valves should be staggered. For valves with large opening force, low strength, high brittleness and heavy weight, a valve frame should be set up to support the valve before installation to reduce starting stress. When installing a valve, use a pipe wrench on the pipe close to the valve and a regular wrench on the valve itself. At the same time, when installing, the valve should be in a semi-closed state to prevent the valve from rotating and deforming. The correct installation of the valve should ensure that the internal structural form conforms to the flow direction of the medium, and the installation form conforms to the special requirements of the valve structure and operating requirements. In particular, it should be noted that valves with medium flow direction requirements should be installed according to the requirements of process pipelines. The arrangement of the valves should be convenient and reasonable, and the operators should be able to easily access the valves. For lift-stem valves, operating space should be left. The valve stems of all valves should be installed upward as much as possible and perpendicular to the pipeline.Installation of valve connection surface.
Hebei Zhenchen believes that when installing a valve with a threaded end, the thread should be screwed into the valve to an appropriate depth. If the thread is screwed in too deep, the valve seat will be compressed, which will affect the good cooperation between the valve seat and the gate. If the thread is screwed in too shallowly, the valve seat will be tightened. Affects the sealing reliability of the joint and easily introduces leakage. At the same time, the thread sealing material should be PTFE raw tape or sealant. Be careful not to put the sealing material into the inner cavity of the valve. For valves with flange end connections, the connection surface of the flange must be aligned first, the cover should be perpendicular to the pipeline, and the bolt holes must be aligned. The valve flange should be parallel to the pipe flange, the flange gap should be moderate, and there should be no misalignment or inclination. The center gasket between flanges should be placed in the center and cannot be skewed. The bolts should be tightened symmetrically and evenly. Prevent forced connection tightening when the valve is installed, resulting in an additional residual force. Hebei Zhenchen believes that before installation, the dirt on the inner wall and external threads of the pipe must be thoroughly removed; burrs, foreign objects, etc. that hinder the flow of the medium and may affect the operation of the equipment must be removed, and the dirt, slag and other debris in the pipe must be blown away before the pipe is connected. . Prevent damage to the sealing surface of the valve or block the valve. When installing a welded end connection valve, you should first assemble the welding joints at both ends of the valve after spot welding, open the valve, and then weld the welds according to the welding process. After welding, check the appearance and internal weld quality of the welds to ensure that there are no pores , slag inclusions, cracks, etc., radiographic or over-control inspection of the welds should be carried out when necessary.
When installing a heavier valve (DN>100), use lifting tools or equipment. The lifting rope should be tied to the flange or bracket of the valve and should not be tied to the handle stem of the valve to avoid damage to the valve.