Weituo Weituo Fluid Equipment WATO Wuhan Weituo Fluid Control Equipment Co., Ltd.

The gate valve is a gate for opening and closing parts. The movement direction of the gate is perpendicular to the direction of the fluid. The gate valve can only be fully opened and fully closed, and cannot be adjusted or throttled. The gate valve is sealed by the contact between the valve seat and the gate plate, and the sealing surface is usually welded with metal materials to increase wear resistance, such as 1Cr13, STL6, stainless steel, etc.

There are many domestic manufacturers of gate valves, and most of the connection dimensions are not uniform. Mainly divided into the following categories:

1, the standard valve of the Ministry of Machinery produced according to JB/T2203-1999 "Gate Valve Structure Length";

2. National standard valves produced according to GB/T12221-2005 "Metal Valve Structural Length".

3. American standard valves produced in accordance with ASME B16.10-2009 "Face-to-face and End-to-End Dimensions of Valves".

gate valve can be divided into:

1 Rising stem gate valve: The stem nut is on the bonnet or bracket. When opening and closing the gate, the stem nut is rotated to achieve the lifting of the stem. This structure is beneficial to the lubrication of the valve stem, and the degree of opening and closing is obvious, so it is widely used.

2 Dark stem gate valve: The stem nut is in the valve body and is in direct contact with the medium. When opening and closing the gate, it is realized by rotating the valve stem. The advantage of this structure is that the height of the gate valve always remains the same, so the installation space is small, and it is suitable for gate valves with large diameters or restricted installation space. This structure should be equipped with an opening and closing indicator to indicate the degree of opening and closing. The disadvantage of this structure is that the valve stem thread is not only unable to be lubricated, but it is directly corroded by the medium and is easily damaged.

The main difference between bright stem gate valve and dark stem gate valve:

1. The lifting screw of the concealed rod flange gate valve only rotates without moving up or down. The exposed rod is only a rod. The nut is fixed on the gate. The gate is lifted by the rotation of the screw, and there is no visible door frame. ; The lifting screw of the rising stem flange gate valve is exposed, the nut is close to the handwheel and is fixed (not rotating or moving axially), the gate is lifted by rotating the screw, and the screw and the gate only have relative rotational movement. There is no relative axial displacement, and the appearance is a gate-shaped bracket.

2Dark stem valve means that the lead screw cannot be seen, while the open stem valve can see the lead screw.

3. The steering wheel and the valve stem are connected together and relatively immobile when the dark stem valve is opened and closed. The valve stem is rotated at a fixed point to drive the valve disc to lift up and down to complete the opening and closing. The rising stem valve raises or lowers the disc through the threaded drive of the valve stem and the steering wheel.

The simple point is that the rising stem valve is the valve disc connected with the stem to move up and down, and the steering wheel is always at a fixed point.