Classification and application of ball valves

Ball valves are mainly used in the pipeline to cut off, distribute and change the flow direction of the medium.
ball valve is a new type of valve widely used in recent years, which has the following advantages: 1. The fluid resistance is small, and its coefficient of resistance is equal to the length of the pipe segment.
2. Easy to operate, open and close quickly, from full open to full off as long as the rotation of 90 degrees, easy to control long distances.
3. Easy maintenance, simple ball valve structure, sealing ring is generally active, removal and replacement are more convenient.
4. Simple structure, small size, light weight.
5. Close and reliable, the sealing surface material of the ball valve is widely used in plastic, good sealing, and has also been widely used in vacuum systems.
. At full opening or closing, the sealing surface of the sphere and seat is isolated from the media, which does not cause the valve seal surface to erode when it passes through.
ball valve has been widely used in petroleum, chemical, power generation, paper, atomic energy, aviation, rockets and other departments, as well as people's daily life.
ball valve can be divided according to the structure form: First, forged steel fixed ball valve ball valve sphere is fixed, pressure does not produce movement.
the fixed ball valve with a floating seat, under media pressure, the seat produces movement, so that the seal ring pressed on the sphere, to ensure the seal.
are usually fitted with bearings on the upper and lower shafts of the larger bodies, operating with small twisting distances and suitable for high-pressure and large-calibre valves.
In order to reduce the operating torque of the ball valve and increase the reliability of the seal, in recent years, there have been oil-sealed ball valves, both in the sealing surface press special lubricants, in order to form a layer of oil film, that is, enhance the sealing, but also reduce the operating torque, more suitable for high-pressure large-caliber ball valve.
, the sphere of the elastic ball valve is elastic.
sphere and seat seals are made of metal materials, the seal ratio is very large, relying on the pressure of the medium itself has not reached the requirements of the seal, external forces must be applied.
valve is suitable for high temperature and high pressure media.
elastomer is an elastic groove at the lower end of the wall of the sphere to obtain elasticity.
when closing the passage, use the wedge head of the stem to open the sphere and press the seat to seal.
release the wedge head before turning the sphere, the sphere is restored to its original shape, resulting in a small gap between the sphere and the seat, which reduces friction and operating torque on the sealing surface.
ball valve according to its channel position can be divided into straight-through, three-way and right-angle.
ball valves are used to distribute the medium and change the flow of the medium.
3. The sphere of the hard-sealed floating ball valve valve is floating, under the action of media pressure, the ball can produce a certain displacement and press on the sealing surface of the outlet end to ensure the outlet seal.
The structure of the floating ball valve is simple and well sealed, but the load of the sphere-loaded medium is passed to the outlet seal, so consider whether the sealing ring material can withstand the working load of the sphere medium.
this structure and is widely used in medium and low pressure ball valves.
ball valves are widely used in irrigation systems, mainly at the in-branch inringing.
The ball valve is simple in structure, small in size, and has little resistance to water flow, with the disadvantage that it opens or closes too quickly and produces a water hammer in the pipe (the pressure increases when the water speed in the pipe suddenly changes).
it is not appropriate to use ball valves on the trunk pipe, which can be used for flushing on dry, branch or end of the pipe, flushing sewage effect is good.
ball valve has O-type ball valve and V-type ball valve.
O ball valve with floating structure, the core is a precision casting, the exterior plated hard chrome treatment, the seat uses enhanced Teflon material, the channel port and pipe caliber, the circulation capacity is very large, the flow resistance is very small, closed without leakage Generally do switch valve use, especially suitable for high viscosity, fiber- and granular media, V-shaped ball valve using a fixed structure, the core has a V-type incision, can achieve proportional adjustment, flow characteristics are approximate and so on.
According to the process equipment is different, can form a high-pressure internal threaded ball valve and forged steel three-piece hard-sealed ball valve, where the high-pressure internal threaded ball valve if you want to achieve proportional adjustment must be equipped with valve locator, forging steel three-piece hard-sealed ball valve if you want to achieve proportional adjustment must choose an electronic electric actitor or with servo amplifier.
the outer threaded ball valve to the weld ball valve is a ball with a circular channel as an opening and closing piece, the ball with the valve stem rotation to achieve the opening and closing action of the valve.
the opening and closing part of the external threaded ball valve to the weld ball valve is a hole-in-the-hole sphere that rotates around the axis perpendicular to the channel, thus achieving the purpose of opening and closing the channel.
ball valves are mainly used to open and close pipes and equipment media.