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What are gate valves generally used for

Gate valve is the valve that the closing member (gate) moves in the vertical direction along the center line of the pathway. Gate valve in the pipeline can only be used for full open and full shut-off, not for regulation and throttling. Gate valve is the use of a wide range of valves, general DN ≥ 50 mm diameter cut-off devices are selected it, sometimes very small diameter cut-off devices also use gate valves.

The gate has two sealing surfaces, and the two sealing surfaces of the most commonly used pattern gate valve form a wedge, wedge angle varies with the valve parameters. Wedge gate valve gate can be made into a whole, called rigid gate; can also be made into a gate that can produce a small amount of deformation, in order to improve its craftsmanship, to compensate for the deviation of the sealing surface angle in the process, this gate is called a resilient gate.  

When the gate valve is closed, the sealing surface can only rely on the medium pressure to seal, that is, rely on the medium pressure will be the sealing surface of the gate to the other side of the seat to ensure the sealing surface of the seal, which is self-sealing. Most of the gate valves are forced to seal, that is, when the valve is closed, rely on external force to force the gate plate to the seat, to ensure the sealing surface of the seal.  

The gate valve's gate plate moves in a straight line with the valve stem, and is called a lift stem gate valve (also called a bright stem gate valve). Usually there are trapezoidal threads on the lift rod, and the rotary motion is changed to linear motion through the nut at the top of the valve and the guide groove on the valve body, which means the operating torque is changed to operating thrust.  

When the valve is opened, the passage of fluid is completely open when the height of the gate lift is equal to 1:1 times the valve diameter, but this position cannot be monitored during operation. In actual use, the top point of the valve stem is used as a marker, i.e., the position of open immobility, as its fully open position. In order to take into account the locking phenomenon of temperature changes, it is usually opened to the apex position, and then reversed 1/2-1 turn, as the fully open position of the valve. Therefore, the valve's fully open position, according to the position of the gate (i.e., stroke > to determine.

Cautions

1.Gate valves are usually used in open-close applications and cannot be used for throttling applications.

2. Gate valves are usually installed in horizontal pipelines with the stem upward vertically. They can also be installed in vertical pipelines or horizontal pipelines where the stem is not vertically upward, but special construction may be required depending on the valve's diameter size, application environment and material specifics.

3. For applications where the temperature exceeds 260°C, a flexible or collocated wedge gate is recommended to avoid jamming of the wedge gate due to thermal expansion. This situation may occur when the valve is cold closed and then hot open state.

4. When used for high velocity fluid (turbulent flow) or thermal cycle applications, the threaded seat ring should be lock welded to the valve body in order to avoid loosening.

5. After closing the gate valve, the stem should be turned back slightly (1/8 to 1/4 turn) to relieve the stem load. This allows the stem to expand slightly without jamming or damaging the valve and without affecting the closing effect.

6. If the seat ring mounting lugs are removed, the highly integral shut-off gate valve can be used in hot water outlets or in piping systems using soft iron.

7. pumping station use is not limited by the site, more debris in the water, easy to block the important location of the valve, you can use the hand and electric gate valve; conversely, you can use the butterfly valve, especially used in the pump room renovation project can be used butterfly valve, in order to effectively use the space of the original pump room, to achieve the original pump room area remains unchanged under the premise of improving the supply (discharge) water.

STANDARD MATERIALS OF MAIN PARTS

ITEM	PART NAME	MATERIAL
1	Body	GGG50
2	Seat	EPDM
3	Shaft	SS420
4	Disc	GGG50
5	Wedge Nut	Brass
6	Bonnet Gasket	EPDM
7	Binnet	EPDM
8	Sealing Ring	EPDM
9	Socket Head Screw	A2-70
10	Oring	EPDM

PRESSURE

NOMLNAL PRESSURE		1.6	Mpa
Testing Pressure	Shell	2.4
	Seallng	1.76

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