WEDGE GATE VALVE AND METHOD OF SECURING SEALING RINGS IN LOCK OF WEDGE GATE VALVE Russian patent published in 1999 - IPC

FIELD: locks of pipe line fittings. SUBSTANCE: body or wedge of gate valve is provided with grooves for sealing rings. Surfaces of sealing rings of body or wedge which are to be bonded are spherical in shape and respective engageable surfaces of grooves of body or wedge are spherical or conical. Adhesive layer connecting the sealing rings with body and wedge consists of thin layer of primer and main layer of adhesive. Primer is applied directly on surfaces to be bonded forming high and steady adhesion with metal under operating conditions. Main layer of adhesive is applied on primer layer providing for protracted strength of joint during operation. Spherical surface of sealing ring-is provided with system of parallel coaxial grooves holding adhesive in their volume excluding its extrusion from joint of bonded surfaces in the course of their plastic contact during tightening up the wedge. Sealing rings may be also bonded over cylindrical surface and over spherical surface on wedge. In this case, self-setting of engageable sealing surface of body and wedge is ensured due to turn of rings on wedge over cylindrical surface. In preferable versions, sealing rings received by grooves of body are fitted over spherical surface and sealing rings received by grooves of wedge are fitted over cylindrical surface. In turning the opposite grooves with spherical surfaces in inner cavity of body, use is made of double-sided forming tool ensuring machining both grooves with no change in position of body due to change of direction of axial motion of revolving boring bar with tool. EFFECT: enhanced tightness of lock. 7 cl, 4 dwg