Pneumatic valves and hydraulic pressure based on a certain air, water or oil as a power source Guangzhou Kaiheng Valve Co., Ltd., an air cylinder (or cylinders) and the movement of the piston to drive the valve, general pneumatic air pressure is less than 0.8MPa Taiwan Toyama Valve Co., Ltd., hydraulic pressure or oil pressure is 2.5MPa ~ 25MPa. As for driving the diaphragm; rotary gas, liquid drive means for driving the ball, butterfly or plug. The driving force of hydraulic devices, suitable for driving large diameter valves. As for the drive plug, ball and butterfly valves Shanghai Guanlong Machinery Co., reciprocating piston must be converted from Rotary movement. In addition to the use of an air cylinder or a hydraulic cylinder piston to drive, there is the use of pneumatic diaphragm-driven, and the driving force is small because of the trip, it is mainly used to adjust the valve. GB / T12242-2005 safety valve performance test method GB / T12245-2006 valve performance test method GB / T12251-2005 steam traps - Test method GB / T13927-2008 Universal valve pressure test JB / T5296-1991 common valve flow coefficient and Test Method for flow resistance coefficient Shanghai and Shanghai Valve Manufacturing Co., the Hong Kong _ valve (Online) _ valve provided by the valve, the Hong Kong Science and Technology Co., Ltd. of Dongguan. Valve Co., Ltd., Dongguan Ming Kong (www.gdmgfm.com) is Dongguan, butterfly leaders, over the years, the company implement the scientific management, innovation and development, the principle of honesty and trustworthiness, and satisfy customer needs. Ming Kong valve leadership with the staff warmly welcome all inquiries negotiations to create a better valve out of Hong Kong in the future.