Pneumatic control valve action points gas open type and close type two kinds

pneumatic regulating pneumatic valve movements on the two points type gas and gas type. Open type ( Gas) Is the air pressure head when the increase of the film, pneumatic valve open direction, to increase the movement, when the input pressure limits, pneumatic valve in the fully open position. Conversely, when the air pressure drop, pneumatic valve closed in the direction of movement under the condition of the input air, pneumatic valve is fully closed. It is sometimes referred to as fault pneumatic valve is closed to the open air, Fail closed CaiWeiHui) 。 Type gas down ( Gas off) The movement direction of the reverse and gas. When the air pressure, pneumatic valve move to the closed position, direction of air pressure drop or inappropriate pneumatic valve to open or fully open. It is sometimes referred to as the open failure ( Unable to open) 。 Pneumatic air pneumatic valve open or closed air, through the positive and negative of different means of actuators and pneumatic valve, usually the role of parliamentary state structure.
15, the selection of gas gas production process is based on the safety point of view to consider problem. When the air cut off power supply, voltage stabilizer safety pneumatic valve is in the closed position, or open position? For example, a furnace combustion control, regulating the orbit of fuel pipe installed pneumatic valve, according to the furnace or heating temperature at furnace outlet temperature control fuel supply of materials. At this time, you should use a more secure gas pneumatic valve to open, because once stop gas source supply, pneumatic valve is closed more suitable than the pneumatic valve fully open. If fuel gas supply disruptions, pneumatic valve fully open, excessive heat will be dangerous. Another example, and the heat transfer of cooling water equipment, hot material cooling, heat and cooling of the cooling water heat exchanger cooling water control pneumatic valve installation, and to control the material after cooling water temperature and heat exchanger in air supply interruption, pneumatic control valve should be in the open position more secure, gas type should be chosen ( That is,) Pneumatic valve.
the change of the open type of gas or gas to cut off the gas to change type gas open, as in the installation of field intelligent pneumatic valve positioner can easily switch to the other party. But there are also many failures do not want the pneumatic valve is in full open or close position, the operation is not allowed, but not to maintain the last breath in front of the original position. At this time, you can take some other measures, such as pneumatic valve, or set to mortgage, air tanks and other facilities, to ensure that the location of the accident he.