Non-rising stem gate door and gate valve gate to distinguish

Gate valve door according to the structure of the valve stem can be divided into: 1 rising stem gate valve gate: the valve rod nut on the valve cover or stents, open and close the damper, with rotary valve stem nut to realize the rise and fall of the valve rod. The lubrication of the valve rod structure, the degree of opening and closing, so widely used. 2 non-rising stem gate valve gate: the valve rod nut in the valve body, direct contact with the media. Open and close the damper, the rotary valve rod was used to implement. The advantage of this structure is: the height of the gate door always remains the same, so the space is little, installation is suitable for large diameter or gate valve gate of limited installation space. With this kind of structure to open and close indicator, to indicate the degree of opening and closing. The disadvantage of this structure is: the valve stem threads not only unable to lubrication, and directly to medium erosion, easy to damage. Rising stem gate valves door and non-rising stem gate door. The main difference: 1. Non-rising stem flanged gate valve door is the ascension of the screw rotation and only under the supreme and moving, the leakage is a lever, the nut is fixed on the disc, improve ram through the rotation of the screw, no visible door frame; Rising stem flange gate valve gate lifting screw is exposed, nut is close to the handwheel and fixed ( Not rotating axial movement) , improve ram through rotation of the screw, the screw and the rotation of the damper is the relatively movement without the relative axial displacement, appearance is a door shape bracket. Rising stem gate valves door and non-rising stem gate valve gate 2 screw non-rising stem of the valve gate is can't see, and Ming is that can see the screw rod. 3. Non-rising stem valve door switch in the steering wheel with the valve rod is connected to the relatively fixed, it is in fixed point through the valve rod rotation to drive valve disc up and down the brake to complete opening and closing. Rising stem gate valve by valve stem and screw thread of the steering wheel drive to ascend or lowered the valve disc. Simple point said is rising stem gate valve is the valve disc attached to the valve rod do up and down together, the steering wheel is always in the attachment.