Author:Site Editor Publish Time: 2019-05-19 Origin:Site
Valve professionals often refer to the term "internal" when talking about industrial gate valve. But they are not talking about the pros and cons of valve assembly, but rather the internal components that are subjected to extreme stresses or harsh conditions that combine corrosion and corrosion.
Here are the content list:
1.The internals in the gate valve;
2.Body/bonnet design structure;
Internals in the gate valve
The internals in the gate valve have a stem, a disc seal area, a seat and an upper seal (if any). The inner material of bronze and brass valves is usually the same as that of the valve body and bonnet.
Cast iron and ductile iron valves have all-iron internals or occasionally bronze internals. This iron valve with bronze internals is called "bronze-filled iron valve" or abbreviated as IBBM. Due to the weldability of steel valves, steel valves can be fitted with a large number of different internals. Stellite, Hastel, 316ss, 347ss, Monel and Alloy No. 20 are materials for common internals of gate valves.
Most of the 19th century offers threaded end valves that are up to 12 inches in size. After the 19th century, flanged valves became more popular. Other end connection types used today include threaded ends, ring connections,
Body/bonnet design structure
Five differently designed gate valve body/bonnet connections are available: threaded, union, bolted bonnet, welded bonnet and pressure seal.
The threaded connection is the simplest design mechanism. But usually only for cheaper bronze valves that require little disassembly.
The union connection structure is also mainly used for bronze valves, but the union design is easy to repair and maintain.
The bolted bonnet connection structure is the most commonly used connection structure, and most of today's industrial gate valves use this structure. The gasket seal is required for connection between the valve body and the bonnet in the threaded and slip joint configuration.
The pressure seal connection structure is formed by a wedge-shaped soft iron or a spheroidal gasket acting between the valve body and the valve cover by the medium pressure in the valve body. The higher the pressure in the cavity of the valve body of the pressure seal valve, the greater the force acting on the gasket. Pressure-sealed valves are much lighter than bolted bonnet designs.
The welded bonnet is the most common structure for compact steel valves that do not require disassembly for 1/2 to 2 inches and pressures between 800 and 2500 lbs. Similar to pressure-sealed valves, welded structural valves are lighter than bolted bonnet valves.
The above is a detailed introduction to the design of the valve trim and valve body/bonnet.