The bonnet type DVD Resilient Seated Gate Valves have a revolving non-rising stem, provided with a functional thread which is inside the valve chamber.

During the operation, stem revolves in the stem nut which carries along a solid wedge which is vulcanized by rubber. Due to its design, low torque values are achieved which eases the revolving of the stem.

The stem is locked against axial movement by a bonnet nut threaded to the bonnet, and no axial movement occurs in the specified conditions.

The wedge is guided in the body in a precast groove and provides an undisturbed water flow when the valve is open.

The body and the vulcanized wedge do not have pressed-in sealing seat. Without the sealing seat, residuals do not collect inside the valve which allows a drip tight closure even in dirty water. Moreover, vulcanized wedge can stretch in case a residual is stuck between the body and the wedge at the time of closure, so that sealing is achieved.