Overview of ball valves：
The ball valve was introduced after the Second World War, although its invention can be traced back to the early 20th century, this structure patent due to the limitations of the materials industry and mechanical processing industry at that time failed to complete its commercialization steps. In 1943, DuPont invented a polymer material polytetrafluoroethylene (PTFE) plastic, this material has sufficient tensile and compressive strength, a certain elasticity, good self-lubricating properties, and excellent corrosion resistance, is very suitable as a sealing material, can obtain a very reliable sealing effect. On the other hand, due to the progress of the ball turning machine and ball grinding machine, it is possible to process the ball with high roundness and surface finish as the opening and closing parts of the ball valve.
In this way, a full diameter, 90 ° angle stroke rotary valve new species into the valve market, attracting widespread attention, and gradually replacing the traditional valve products globe valve, gate valve, plug valve, and butterfly valve, and constantly expanding its application areas, from small diameter to large diameter, from low to high pressure, from room temperature to high temperature, to low temperature. At present, the maximum diameter of the ball valve has been developed to 60in, the highest pressure level of 4500 pounds, the lowest temperature can reach the liquid hydrogen temperature -254 ℃, the highest temperature up to 850 ~ 900 ℃, for a variety of media and gas-solid, liquid-solid two-phase flow, become the most promising type of valve development.
Ball valve on the structure principle：
The ball valve on the structure principle can be divided into a floating ball fixed seat ball valve, referred to as a floating ball valve (floating ball valve), and a fixed ball floating seat ball valve, referred to as a fixed ball valve (trunnion mounted ball valve) two categories.
According to the structure of the valve body, can be divided into a top-mounted ball valve and a side-mounted ball valve. The side-mounted ball valve can be divided into integral, two-stage, and three-stage, that is, the valve body is integral, the valve body consists of the main and secondary valve body and the valve body consists of a main body, two secondary valve body composed of three structural forms.
Ball valves are classified according to material：
According to the valve sealing material, can be divided into soft seal ball valve and hard seal ball valve. Soft seal ball valve sealing materials: polytetrafluoroethylene (PTFE), reinforced polytetrafluoroethylene, nylon and other polymer materials and rubber; hard seal ball valve sealing materials for metal.
Ball valves are classified according to function：
According to the function of the valve, can be divided into two-way switching valve, three-way and four-way directional valves, and regulating ball valves.
Ball valves are classified according to operation mode：
According to the operation mode, it can be divided into manual, ray wheel drive, pneumatic, gas-hydraulic linkage, electric, electro-hydraulic linkage, hydraulic, etc.
According to the valve connection, can be divided into flange end connection, welded end connection and threaded end connection. The welding end can be divided into socket welding and butt welding connection.
In addition, according to the needs of the user’s working conditions directly named special ball valves, such as pipeline ball valves for long-distance pipelines; jacketed ball valves for pipeline heating, insulation; plastic-lined ball valves for corrosion prevention; lock slag ball valves for gasification furnace slag discharge, as well as for high-temperature and high-pressure steam hydrophobic ball valves in power plants.
According to the shape and size of the ball valve opening and closing member sphere, can be divided into V-shaped ball valve, half ball valve, full diameter and reduced diameter ball valve, etc..
According to the use of media temperature, can be divided into high temperature ball valve, low temperature ball valve and deep cold ball valve.
According to the valve body material, can be divided into carbon steel ball valves, stainless steel ball valves, titanium alloy ball valves, Monel ball valves, plastic ball valves, copper ball valves, aluminum ball valves, etc.
TAG: ball valve, wesdom
