For the first time exposure electric pneumatic valve and pneumatic regulating pneumatic valve manufacturing process

regulating pneumatic valve production process are made by a variety of control loop was associated with control network established, regulate the process of pneumatic valve control loop test, control, execution three links with the controlled production process equipment.
process elements: control circuit components in addition to the controller of all combinations. Process components including pneumatic control valve components, controlled object, such as pressure vessel or heat exchangers, and sensors, pump and transmitter, and so on.
closed loop: a way of process components are connected. Information about the process variables are continuous feedback to the controller set point, to continuously and automatically correct the process variables.
open loop circuit: the connection process control was interrupted, process variable information feedback to the controller set point no longer, so to correct the process variable is no longer. Such as the controller is set in manual operation state.
controller: a certain established arithmetic to adjust the control variables by using the automatic operation of the device. Controller input to receive information about the state of the process variables, and then provides a corresponding output signal to the terminal control components.
control pneumatic valve: the most commonly used in industrial process control terminal element is the control of pneumatic valve. Control pneumatic valve to mobilize the flow of fluid, such as gas, steam, water or chemical compounds, to compensate for the load disturbance and the controlled variables as much as possible close to the process of the set point.
control pneumatic valve components; All parts including the installed on regulating pneumatic valve, pneumatic valve regulating pneumatic valve components, provides the driving force of the actuator, pneumatic valve operations and all kinds of pneumatic valve. Regulating pneumatic valve attachment is installed on the executing agency to fill a shell actuator functions and can make it a complete operating unit of the device. Such as locator, converters, gas pressure regulator, manual manipulator, dampers, electromagnetic pneumatic valves, limit switches, etc.
actuators: a force or motion to open or close the pneumatic valve pneumatic, hydraulic and electric device.
the locator: a position servo control. It is connected to the terminal control on mechanical components or a movement of the actuator of its component parts, automatically adjust the output of the actuator, to keep a proportional to the input signal of pneumatic valve position.
flow coefficient: one associated with the geometric structure and a given schedule of pneumatic valve of constant, used to measure flow capacity.
said regulating pneumatic valve flow coefficient of symbols such as C, Cv, Kv, their operation unit is different, also have different definition.
　　C- Engineering system of units ( MKS system flow coefficient, in the domestic use for a long time. - defined as temperature ℃ water in LKGF/cm ( O. LMpa pressure drop and flow through hours of regulating pneumatic valve on the number of cubic meters. 简历- English unit and flow coefficient, defined as: temperature ℃ F ( 。 ℃ water in the lib/in ( Kpa pressure drop through the regulating pneumatic valve on the number of American gallons per minute. Kv - The international system of units ( The flow coefficient of the SI system, defined as: temperature - ℃ water, hours through regulating pneumatic valve on the number of cubic meters.
note: the relationship between C, Cv, Kv Cv =. Kv, Kv = l。 C
flow characteristic: when rated travel percentage from changes to %, flows through the pneumatic valve as a percentage of maximum flow and the relationship between the rated travel percentage.
equal percentage features: a kind of inherent flow characteristics: rated stroke equal increments will ideally produce the percentage of change such as maximum flow.
linear characteristic: a natural flow characteristic, rated stroke amount increases with the increase of the maximum flow proportional. Can be expressed in a straight line on the flow characteristic figure it out.
quick opening features: a kind of inherent flow characteristics, the percentage is very low, such as stroke location provides great flow change:
flashing, cavitation definition description: when the pressure is P fluid through the orifice, velocity suddenly increased dramatically and static pressure plummeted, after the hole pressure P at or below the saturated vapor pressure fluid in the case when the Pv part, liquid vaporization as the gas forming steam-liquid two-phase coexisting phenomenon, this phenomenon is called flash.
create flash, to the material such as pneumatic valve core has started to have erosion damage, and affects the correctness of the formula of liquid, complicate calculation. If produce flash, P is not remain below the saturated vapor pressure, after leaving orifice and rapid rise, then the bubble burst and translated into liquid, the process is the cavitation.