Basic Knowledge of Industrial Valves-about gate valves, butterfly valves, check valves, globe valves, ball valves-Part One

1. Definition of Industrial Valves-what is industry valve:    

Industry valve is a mechanical device which is used to control the flow area size, and to control the flow rate, pressure, and flow direction in the pipe line system with mediums like liquid or gas.

2. Classification of industrial valves: 

A. Classified by applications and functions: 

①:Shut off valves: the industrial shut off valves are widely used to connect and cut off the mediums, like globe valves, soft seal/hard seal gate valves, ball valves(soft seal ball valves, hard seal ball valves), butterfly valves( wafer butterfly valves, lug type butterfly valves, soft seal butterfly valves, hard seal butterfly valves, flange butterfly valves),etc. 

②:Check valves series: that kind of industrial check valves are widely used to prevent the mediums flowing back, like check valves( wafer butterfly valves, ball type check valves, swing check valves, rubber disc check valves), foot valves,etc. 

③:Regulating valves series: the industrial regulating valves are usually used to regulate the mediums flow rate and pressure, like regulating valve( also called control valves, pressure control valves), throttle valves( also known as throttling valves, flow controlling valves, flow regulating valves, butterfly throttle valves), pressure relief valves( also called relief valves, industrial relief valves, pressure reducing valves, pressure reduction valves). 

④:Split flow valves: this split flow valves are generally used to distribute or split the mediums or mix the mediums in the pipe line systems. Like multi-port ball valves, plug valves, drain valves or traps, etc. 

⑤:Safety valves: The so-called safety valves are widely applied to prevent the pipe pressure from exceeding the settled value, to work as the role of over-pressure protection. Like safety valves, relief valves, pressure relief valves. 

B. Classified by driving devices. 

①:Manual valves(also known as hand/manually operated valves, lever handle valves,worm gear valves, valves with worm gear box): this kind of manual valves are operated through man power, driven by hand-wheel or lever hand. 

②:Power driven valves: this kind of power driven valves are usually operated through various powers, like electrically-operated valves, pneumatic valves, hydraulic valves. 

③:Automatic valves: for that kind of automatic valves, there is no external forces required, the force generated by the mediums itself will be used to open and close the disc. Like check valves( including wafer butterfly check valves, ball type check valves, swing check valves, rubber disc check valves), pressure relief valves, safety valves, drain valves. 

C. Classified by nominal pressure: 

①:Vacuum valves: this vacuum valve is for those valves whose working pressure is less than 1.0Mpa. 

②:Low pressure valves: the low pressure valves is for those industrial valves whose working pressure is ≤1.6MPa. 

③:Middle pressure valves: the middle pressure valves is for those industrial valves whose working pressure: 2.5Mpa=Pressure≤6.4MPa. 

④:High pressure valves: high pressure valves is for the valves whose working pressure: 10MPa≤working pressure≤80MPa. 

⑤:Super high pressure valve: the super high pressure valve is for the valves whose working pressure is ≥100MPa. 

D. Classified through working temperature: 

①:Low temperature valve: the low temperature valve is for those valves whose working temperature is ≤-40℃. 

②:Normal temperature valves: the normal temperature valves is for those valves whose working temperature is: -40℃＜working temperature≤120℃. 

③:Middle temperature valves: the middle temperature valves is for those valves whose working temperature is: 120℃＜working temperature＜450℃. 

④:High temperature valves: the high temperature valves is for the valves whose working temperature is ＞450℃. 

E. Classified by the valve’s nominal diameters: 

①:Small diameter valves: the small diameter valves is for the valves whose diameter is 40mm(DN≤40mm). 

②:Medium diameter valves: the medium diameter valves is for the valves whose diameter is between 50-350mm which means DN50-350mm. 

③:Large diameter valves: the large diameter valve is for those valves whose diameter is between 400mm-1200mm.(DN400-DN1200mm) 

④:Super large diameter valves: the super large diameter is for those valves whose diameter is over 1200mm. (DN＞1200mm). 

F. Generally Known classification method: 

①:Gate valves: the gate valves is for those industrial valves whose valve disc(valve plate) is driven by the valve stem/valve shaft, and move vertically along the sealing surface of the valve seat. 

②:Globe valves: the globe valves is for those industrial valves whose opening and closing part(which is called valves disc or valve plate) is driven by the valve stem to do up and down movement along the axis of the sealing surface of the valve seat. 

③:Check valves: the check valves is for the industrial valves whose opening and closing part(called valve disc or valve plate) will use the force generated by the mediums to prevent the mediums from flowing back. The check valves include swing check valves, ball type check valves, rubber disc check valves, butterfly wafer check valves) 

④:Ball valves: Ball valves is for those industrial valves whose opening and closing parts(known as the ball body) will rotate along the axis line which is perpendicular to the flow direction. 

⑤:Butterfly Valves: the butterfly valves is for those industrial valves whose opening and closing part known as the valve disc rotate along the settled axis line which is perpendicular to the flow direction.