The repair of the safety valve is mainly for the repair of the safety valve sealing surface, so the safety valve sealing surface material has higher requirements, the basic requirements are: a higher strength, can withstand a higher sealing pressure;
It has a certain impact toughness and can withstand the impact of the spool's quick take-off and return seat.
High hardness, can withstand medium erosion;
Can not rust, otherwise soon leakage;
To withstand high temperature, not high temperature become soft;
To corrosion resistance, can withstand acid and alkali and other erosion.
The main forms of the hard seal of the safety valve include the plane seal, the conical seal, the spherical seal and so on. The most commonly used is the plane seal.
(1) repair the sealing surface of the safety valve.
Safety valve sealing surface has two kinds of metal and non-metal, non-metal seal is generally used in normal temperature medium, metal seal is used for high temperature and high pressure medium.
After the sealing surface of non-metallic material is damaged, the insert ring (sealing ring) is generally removed and replaced, and can not be removed or can only be used for turning without spare parts.
Metal sealing surface in the case of not too serious damage, are used in the way of grinding.
Grinding is divided into coarse grinding and fine grinding.
The valve seat and spool must be ground separately with flat grinding tools, and can not be ground, because the grooves appear after grinding, and the leakage occurs after the opening of the seat.
(2) grinding tools and materials.
1).
Grinding plate :1 cast iron (for rough grinding);
Hard alloy (used for fine grinding).
Grinding head (for grinding valve seats).
2) abrasive.
Chromium oxide, white corundum, 280, 360, 600, W4, W2.5, W1.5.
3) grinding agent.
Oleic acid, oil, rapeseed oil, lard.