Transportation machinery Ball introduction

Evolved from the plug opening and closing member is a sphere, with the sphere around the torsion axis of the stem 90 ° to achieve the purpose of opening and closing the main

valve for cutting off the pipe, and changing the direction of media flow distribution, imagine a V shaped opening of the ball also has good flow adjustment

Degree function.
Strengths:
(1) has the lowest flow resistance (theory 0)
(2) does not result in the obligation stuck (without lubricant) it can be reliably used in aggressive media and low boiling liquids;
(3) In the large pressure and  curve conveyor  temperature range, can be completely sealed;
(4) can be fast opening and closing, opening and closing times of certain structures only 0.05 to 0.1 in order to secure for the test bed automation system. Quick opening and

closing valves, domination no impact.
(5) spherical closure member can be automatically positioned on the location of the frontier;
(6) on both sides of the working medium in a reliable seal;
(7) In the fully open and fully closed, the ball and seat sealing surface and the dielectric isolation, so the high dielectric top end of the valve does not cause corrosion of

the sealing surface;
(8) is compact, light weight, you can assume it piecemeal for cryogenic medium most reasonable valve structure;
(9) Body symmetry, especially welded body structure, can well withstand the stress from the pipe;
(10) Close parts can withstand the pressure differential.
(11) fully welded ball valve body can be buried in the ground, so that the valve inner parts from erosion, the maximum service life of up to 30 years, kerosene, natural gas

pipeline valve ideal.
Defects:
(1) because the main valve seat ring material is PTFE, for almost all the flesh has a chemical is inert and has a low coefficient of friction, function fluctuations, not aging,

temperature and sealing performance  chain conveyor  for a wide range of excellent The analysis of the features. But PTFE

Physical characteristics, including a higher coefficient of expansion of the dull cold and poor thermal conductivity, pleading seat sealing imagination surround these

characteristics must stop. So, when the sealing material hardens, the reliability of sealing the destruction. And, PTFE temperature levels

Low, only less than 180 ℃ circumstances. Beyond this temperature, the sealing material will be aging. Consider the case of long-term use, usually only at 120 ℃ not used.
(2) its scheduling function with respect to the valve to be worse, especially pneumatic valve (or electric valve)