Standard Specification for Metal Seal Lifting Plug Valve X43H X43Y

Plug valve is a closed or plunger-shaped rotary valve, through the rotation of 90 degrees to plug the valve port and the valve body on the channel mouth connected or separated to achieve the opening or closing of a valve. The stopper of the plug valve may be cylindrical or conical in shape. In a cylindrical spool, the channel is generally rectangular, while in the tapered spool, the channel is trapezoidal. These shapes make the construction of the plug valve light, but at the same time also have a certain loss. Plug valves are best suited for use as cut-off and switch-on media as well as for shunt applications, but may also be useful for throttling depending on the nature of the seal and the erosion resistance of the seal.

A plug valve is a quick-switching, straight-through valve that is normally used for suspended media as it is wiped away from the rotating seal surface and completely prevents contact with the flowing medium when fully open. Another important feature of the plug valve is that it is easy to adapt to a multi-channel structure so that a valve can have two, three, or even four different flow paths. This simplifies the design of the piping system and reduces the amount of valves required and the number of connecting fittings required in the equipment.

Use a plug body with a through hole as a valve for opening and closing. The plug body rotates with the valve stem to realize opening and closing motion. Small non-packing plug valve, also known as

Plug valve "Cork". Plug valve plug body for the cone (also a cylinder), and the valve body with the composition of the tapered hole surface seal pair. Plug is the earliest use of a valve, simple structure, rapid switching, fluid resistance is small. Common plug valves are sealed by direct contact between the machined metal plug body and the valve body, resulting in poor sealability, large opening and closing forces, and easy wear and tear, usually only for low pressures (up to 1 MPa) and small Diameter (less than 100 mm) of the occasion

Metal hard seal Lifting plug valve on both sides of the valve seat sealing surface can be sealed, the use of the valve from the flow of media restrictions. Metal hard seal Lifting plug valve closed, the valve seat by handwheel and the valve seat sealing surface pressure, by increasing the sealing pressure, the plug valve can have better sealing performance. Seat surface of the valve seat is raised, easy to clean sealing surface, the sealing surface is not easy to accumulate crystallization medium, or solid particles. Solid often used in high-temperature chemical plant occasions. Hard seal Lifting plug valve has a variety of structures, there are two common.

A. Handwheel handle type Lifting plug valve, the working principle is: rise, so that the cock and the valve is fully open. Turn the handle first to turn the cock to 90 degrees to the closed position, and then turn the transmission handwheel to drop the cock to seal.

Valve re-opening and closing process of the cock and the valve seat from the phase, so the valve opening and closing is very easy, and the sealing surface in the opening or closing process is not easy to scratch, the valve life. But the use of the handle drive torque is small, so use the nominal size of the valve is usually not large. Handwheel handle Lifting plug valve compact structure, small size, small fluid resistance.

B. mechanical cross-drive lift plug valve, the working principle is: open the valve when the transmission device to turn the valve stem thread to the cock body up. Remove the cock and valve body sealing surface and then drive the cock to rotate 90 degrees to open the valve. When the transmission is turned off, the cocks will not rotate until the cock is turned 90 degrees to the closed position. The driving force will turn the screw to lower the cock and contact with the sealing surface of the valve body.

Mechanical cross-drive can be connected to the cylinder, electric devices, hydraulic systems for remote control.

Mechanical cross drive lift plug valve, to solve the driving device input torque constraints, so that the valve to the large diameter and high pressure direction.

Mechanical cross drive Lifting plug of the cock channel and the diameter of the pipeline, fluid resistance is small, easy to pig. In oil, natural gas long-distance pipeline development is growing.