Inside screw non-rising stem type gate valves are also called as rotating lever gate valves or non-rising wedge gate valves. Nut of stem is inside valve body and connects with media directly. Swing stem to turn on or off gate valves.
 
The disc of inside screw non-rising stem type gate valves is a wedge. Motor direction of wedge is vertical with flow direction. Gate valves can only turn on-off completely. They are not suitable for being used for regulation or throttling.
 
Nut of stem is installed on wedge. Handwheel swings and drives stem to stem, rising wedge. In general, there are trapezoidal threads at the bottom of stem. Due to threads at the bottom of valves and guide grove on clack, rotational motion is changed into rectilinear motion, which means that handling torque is transferred into handling thrust.
 
Materials of non-rising stem type gate valves
Materials of body: Body is mainly made of nodular cast iron, cast steel, stainless steel, ASTM A316L, and given clear indication of grade and actual physical and chemical test data of cast iron.
Materials of stem: Stem should be made of stainless steel (2CR13). Stem of large diameter valves also should be embedded and packaged by stainless steel.
Materials of nut: Nut is made of casting aluminum brass and casting aluminum bronze. Hardness and intensity of nut are higher than those of stem.
Materials of stem bush: Hardness and intensity should not be higher than stem. When being soaked under water, stem bush cannot form electrochemical corrosion with stem and body.
 
Advantages of inside screw non-rising stem type gate valves:
Height of gate valves is maintained. Nevertheless, less is needed for installing valves. The structure is quite suitable for large diameter valves or gate valves having limited installation space. Inside screw non-rising stem type gate valves also should be installed with indicator to show level of turning on-off.