Features and Principles of Steam Control Valve

Do you know the characteristics and principles of the self-tightening seal bonnet of the steam control valve? In fact, the principle of the sealing characteristics of the regulating valve is very simple, which can be divided into two categories, forced sealing and self-tightening, but because these two types make everyone unclear, today we will talk about the self-tightening sealing bonnet of the steam regulating valve. Principle
1. Forced sealing of the steam control valve. Tighten the middle flange bolts and apply a pressing force to the sealing gasket. The pre-tightened gasket is compressed, and the uneven micro gaps on the sealing surface are filled. In this way, the leakage of the medium is prevented, and the initial sealing condition is formed. A pre-tightening pressure is formed on the sealing surface. When the medium pressure rises and the valve is operated, the preload specific pressure on the sealing surface drops and the gasket rebounds. The typical structure of forced sealing is flat gasket seal, surrounding gasket seal and toothed gasket seal. Usually used for low pressure, medium pressure and small and medium diameter steam control valves.
2. Before the self-tightening seal of the steam control valve increases the pressure, first tighten the bolts to raise the bonnet, so that the initial sealing condition is formed between the bonnet and the wedge seal and between the valve body and the wedge seal. Preload ratio pressure. When the medium pressure rises, the valve cover moves upwards under the action of the medium pressure, and the specific pressure of the seal between the steam regulating valve cover and the wedge-shaped gasket and the valve body and the wedge-shaped gasket gradually increases with the increase of pressure. It should be emphasized that in the self-tightening seal, the medium pressure always tends to increase the pre-tightening seal specific pressure and increase the sealing performance. The higher the medium pressure, the greater the working seal specific pressure and the better the sealing performance. Based on this feature, as a high-pressure sealing technology, self-tightening seals are often used in high-temperature, high-pressure large-diameter control valves.