Valves are usually composed of valve body, bonnet, valve seat, headstock, drive mechanism, sealing piece and fasteners. The control function of the valve depends on the driving mechanism or the fluid driving the headstock to lift, slip, swing or rotate the movement to change the size of the runner area. It is a device used to control fluid flow, pressure and flow, and the controlled fluid can be liquid, gas, gas-liquid mixture or solid-liquid mixture.

The use of valves is very wide, it is closely related to People's daily life, for example, faucet for water pipe, pressure reducing valve used for LPG cooker are valves. Valves are also a variety of machinery and equipment such as internal combustion engines, steam turbines, compressors, pumps, pneumatic actuators, hydraulic actuators, vehicles, ships and aircraft indispensable components.

BC 2000 years ago, the Chinese people in the pipeline used bamboo and wood plug valve, and later in the irrigation channel using the sluice, in the smelting of the bellows using the plate check valve, in the salt mining aspect using bamboo and plate check valve extraction brine.

With the development of smelting technology and hydraulic machinery, copper and lead plug valves appear in Europe. With the use of boilers, in 1681, the lever-heavy-hammer relief valve appeared. Prior to the advent of the 1769 watt steam engine, plug valves and check valves have been the main valves. The invention of the steam engine brought the valve into the field of mechanical industry. In addition to using the plug valve, safety valve and check valve on the Watt's steam engine, the butterfly valve is used to regulate the flow. With the increase of steam flow and pressure, the use of plug valve to control the steam engine's intake and exhaust has not been able to meet the needs, so there is a sliding valve.

Around 1840, the successive emergence of a threaded stem of the cut-off valve, and with trapezoidal threaded stem wedge gate valve, which is a major breakthrough in the development of the valve. The appearance of these two kinds of valves not only satisfies the requirement of increasing the pressure and temperature of various industries at that time, but also meets the requirement of flow regulation initially. Since then, with the development of power industry, petroleum industry, chemical industry and shipbuilding industry, various high pressure valves have been developed rapidly.

After World War II, with the development of polymeric materials, lubricating materials, stainless steel and cobalt-based cemented carbide, old plug valves and butterfly valves have been used for new applications, and the ball valves and diaphragm valves have been developed rapidly. The cut-off valve, gate valve and other valve varieties increase, the quality is improved. Valve manufacturing has gradually become an important sector of the machinery industry.

Valve is an important part of the large-scale equipment, mainly used in the process of pipeline media (materials, water, steam, air and oil, etc.) cut off, throttling, regulating pressure and change the flow. Current international and domestic most commonly used classification method. General points valve, cut-off valve, throttle valve, instrument valve, plunger valve, diaphragm valve, plug valve, ball valve, butterfly valve, check valve, relief valve, steam traps, regulating valve, bottom valve, filter, sewage valve and so on.

After years of development, China's number of valve enterprises in the world's first, the size of valve enterprises about 6,000; The main export enterprises in Wenzhou, Taizhou, Ningbo, Shanghai, Suzhou, Yancheng, etc.

2009, China General Machinery Industry Association Valve Branch of the enterprise export earnings of 589.39 million U.S. dollars, products are mainly sold to the United States, accounted for 20% of total exports, followed by major Japan, South Korea and other countries such as Europe, the Middle East, Taiwan, China and other regions.