The first type is a bolt-type bonnet, which is connected by a concave-convex surface, and is made of a stainless steel strip and a flexible graphite wound gasket, and can also be connected by a ring as needed.
The second type is a welded bonnet that is welded by thread sealing and can be directly welded as required.
The third is a self-sealing bonnet that is threaded into the self-sealing bonnet.
Forged steel valves often overlook the problem of grease injection. After the grease gun is refueled, the operator selects the valve and the grease injection method after the low temperature shut-off valve, and then performs the grease filling operation. There are two cases: on the one hand, the amount of grease is less than that of the grease, and the sealing surface is accelerated by the lack of lubricant. On the other hand, excessive fat injection causes waste. There is no accurate calculation of the different valve sealing capacities based on the valve type category. The sealing capacity can be calculated in terms of valve size and type, and a proper amount of grease can be injected reasonably.