Forged steel gate valve use characteristics and installation

October 10, 2018

Forged steel gate valve use characteristics and installation

Forged steel gate valve features

  • The forged steel gate valve has low flow resistance. The inner medium passage of the valve body is straight through, the medium flows in a straight line, and the flow resistance is small.
  • It is more labor-saving when opening and closing. Compared with the shut-off valve, the direction of movement of the shutter is perpendicular to the direction of flow of the medium, whether it is open or closed.
  • High height and long opening and closing time. The opening and closing stroke of the shutter is large, and the drop is performed by the screw.
  • The water hammer phenomenon is not easy to produce. The reason is that the shutdown time is long.
  • The media can flow in any direction on both sides for easy installation. The gate valve channels are symmetrical on both sides.
  • The length of the structure (the distance between the two connecting end faces of the casing) is small.
  • The sealing surface is prone to wear and affects the service life. When opening and closing, the two sealing surfaces of the gate and the valve seat rub against each other, and it is easy to cause abrasion and abrasion under the action of the medium pressure, which affects the sealing performance and shortens the service life.
  • The price is more expensive. There are many contact sealing surfaces, and the processing is complicated. In particular, the sealing surface on the gate seat is not easy to process, and there are many parts.
  • The utility model has the advantages of simple shape, short structure length, good manufacturing process and wide application range.
  • Compact structure, good rigidity of the valve, smooth passage, small flow resistance, stainless steel and hard alloy on the sealing surface, long service life and PTFE packing. Sealed reliably. Light and flexible operation

Forged steel gate valve installation precautions

  • The handwheel, handle and transmission mechanism are not allowed to be used for lifting, and collision is strictly prohibited.
  • The double gate valve should be installed vertically (ie the stem is in the vertical position and the handwheel is on the top).
  • The gate valve with the bypass valve should open the bypass valve before opening (to balance the differential pressure between the inlet and outlet and reduce the opening force).
  • The gate valve with transmission mechanism is installed according to the product manual. 5. If the valve is used frequently, it should be lubricated at least once a month.

Construction and installation points of forged steel gate valve

  • The installation position, height, and inlet and outlet directions must meet the design requirements, and the connection should be firm and tight.
  • All kinds of manual valves installed on the insulated pipe, the handles must not be downward.
  • The visual inspection must be carried out before the valve is installed. The nameplate of the valve should comply with the current national standard "General Valve Mark" GB12220. For valves with a working pressure greater than 1.0 MPa and a shut-off function on the main pipe, the strength and rigorous performance tests shall be carried out before installation, and shall be used after passing the test.

In the strength test, the test pressure is 1.5 times the nominal pressure, the duration is not less than 5 min, and the valve casing and the packing should be free of leakage. In the rigorous test, the test pressure is 1.1 times of the nominal pressure; the test pressure shall meet the requirements of GB50243 in the duration of the test, and the leakage of the valve sealing surface shall be qualified.