O-ring For Valve Seat

The rubber O-ring is an extruded sealing ring, and the basic working sealing principle of the extruded sealing ring depends on the elastic deformation of the sealing ring, and the contact pressure is caused on the sealing contact surface, and the contact pressure is greater than that of the sealed medium. If the internal pressure is high, no leakage will occur, otherwise, leakage will occur. In order to ensure the sealing effect, the performance of the sealing material and the design of the sealing structure are very important links. For different types of sealing structures, the compression amount and groove design of the O-ring seal are different. Among them, the sealing forms of O-rings mainly include end-face static seals, reciprocating seals, and valve seat seals, all of which have their own different characteristics and structural designs.

So, what are the requirements for the structural design of the valve seat seal in the rubber O-ring?

Take the pilot valve seal as an example to briefly explain the structural design requirements of the valve seat seal.

The sealing surface formed by the valve seat of the valve, the valve disc and the O-ring seal is the valve seat seal. When the system pressure is less than the valve set pressure, the valve is in a closed state, and the valve seat contacts the valve to form an end face called static seal. Conversely, when the system pressure is greater than the set pressure, the valve and the valve seat surface will be disengaged at this time, and the system pressure will be released when the valve is opened. When the system pressure drops to a certain value, the valve returns to the closed state, and the valve seat and the valve disc re-contact to form a static seal on the end face. In the process of opening and closing the valve, the rapid change of pressure will have a certain effect on the sealing surface, and the O-ring is easily blown out or damaged by the accumulated pressure attached to the inside of the groove.

Therefore, the design of the O-ring seal groove of the valve seat sealing ring should not only consider the sealing performance, but also consider the reliable performance of the O-ring sealing ring after the valve seat and the valve sealing ring surface are separated. A common form of valve seat sealing ring is a dovetail groove sealing ring, and different structures have different designs. The sealing ring of the valve seat should not only ensure the volume ratio of the groove, but also prevent the opening of the groove from being too large, which will cause the O-ring seal to be blown out or damaged.