American standard stainless steel low temperature flanged gate valve DZ41W

Low temperature gate valve opening and closing parts is the gate, the direction of movement of the gate and the direction of the fluid perpendicular to the gate valve can only be fully open and fully closed, can not be adjusted and throttling. Gate has two sealing surfaces, the most common mode of the two gate valve sealing surface to form a wedge, wedge angle varies with the valve parameters, usually 50, the medium temperature is not high when the 2 ° 52 '. Wedge gate valve can be made into a whole, called the rigid gate; can also be made to produce trace deformation of the gate to improve its technology to make up the angle of the sealing surface in the process of generating the deviation, the gate The plate is called the elastic shutter.

The type of low-temperature gate valve, according to the sealing surface configuration can be divided into wedge gate type gate valve and parallel gate type gate valve, wedge gate type gate valve can be divided into: single-gate type, double gate type and elastic gate type; parallel gate valve Can be divided into single-gate type and double-gate type. According to the stem of the screw position, can be divided into two kinds of open-gate valve and the dark rod gate valve.

Low temperature gate valve closed, the sealing surface can only rely on the media pressure to seal, that is, relying on the media pressure to the gate of the sealing surface to the other side of the valve seat to ensure the sealing surface of the seal, which is self-sealing. Most of the gate valve is forced seal, that is, the valve is closed, to rely on external force to force the gate pressure to the valve seat to ensure the sealing surface of the seal.

Low-temperature gate valve with the valve stem with a straight line movement, called the lift bar valve (also known as open-gate valve). Trapezoidal threads are usually provided on the lift rods. The rotary motion is changed to linear motion through the nut on the top of the valve and the guide groove on the valve body, ie the operating torque is changed to the operating thrust.

Open the valve, when the gate lifting height is equal to 1: 1 times the valve diameter, the fluid channel is fully open, but in operation, this position can not be monitored. The actual use, is based on the vertex of the valve stem as a sign, that is fixed position, as its full open position. In order to consider the phenomenon of temperature change lock phenomenon, usually in the open to the vertex position, and then back 1 / 2-1 laps, as a fully open valve position. Therefore, the valve fully open position, according to the gate position (ie stroke) to determine.

Some valve, stem nut located in the gate, the hand wheel rotation driven stem rotation, leaving the gate lift, this valve is called the rotary rod gate valve, or called the dark bar.

Valve pressure pieces of precision casting process casting, the surface quality of hand-wheel cast with malleable iron, shape with the handle, the appropriate increase in friction, easy to open. And show a clear "open", "off" signs.

2. Stem nut with high nickel ductile iron, "T" -shaped thread and stem with the transfer of torque.

3. Valve cap with oil cups, regular supplement of solid lubricants, easy to open and close.

4. Packing gland and pressure jacket split design to ensure the concentricity of the stem. Reasonable stuffing box design, to ensure that the valve does not leak, in line with environmental requirements.

5. The valve cover is provided with an upper sealing ring which conforms to the American Petroleum Institute API standard.

6. The valve flange bolts in the use of double-headed bolts, easy maintenance, demolition.

7. Stem head as a whole forging, and the valve through the "T" -type slot connection to ensure strength.

8. DN250 the following castings for precision casting, each batch of castings have furnace number identification, easy to track.