Pneumatic ball valve gauge parameters
Definition of pneumatic ball valve gauge parameters
Pneumatic ball valve is the use of compressed air driven actuators in combination of multiple sets of pneumatic piston movement, the force to beam and the characteristics of the curve track, drive tubular spindle rotation, compressed air disks to each cylinder, changed the direction of gas in and out of position to change the direction of spindle rotation, according to the requirement of the load (valve) the required rotation torque, adjustable cylinder combination number, drives the work load (valve).
Two five-way solenoid valve which is equipped with double-acting pneumatic actuators, two is two position control, on-off, there are five tunnel ventilation, 45 is one connected with gas source, two external and double-acting cylinder chamber in and out of the port connection, two with the internal chamber in and out of the port in succession, you may refer to the working principle of concrete working principle of the double-acting pneumatic actuators. Due to more and more control methods and means, there are many methods to control pneumatic actuators in actual industrial life and industrial control.
1. Nominal diameter (also called mean outside diameter) DN is the common diameter of various pipes and their accessories. Pipes with the same nominal diameter and pipe accessories can be connected with each other and have interchangeability. It is not the actual outer diameter or inner diameter of the pipe, although its value is close to or equal to the inner diameter of the pipe. In order to unify the connection size of pipes and pipe fittings, nominal diameter (also known as nominal diameter and nominal diameter) is adopted. For example, welded steel tubes can be divided into thin-walled steel tubes, ordinary steel tubes and thickened steel tubes according to their thickness. Its nominal diameter is not the outer diameter, nor the inner diameter, but a nominal size similar to the inner diameter of ordinary steel pipe. Each nominal diameter corresponds to an outer diameter, the value of which varies with thickness. Nominal diameter can be expressed in metric mm or in inch. Pipe accessories also use nominal diameter, meaning with the slit pipe.
2.Nominal pressure :(Nominal pressure), denoted by PN, the allowable working pressure of Z under a certain temperature. For the control valve of carbon steel body, it refers to the allowable working pressure of Z under 300℃; For cast iron valve body, refers to the allowable working pressure of Z under 120℃; The control valve of pneumatic ball valve refers to the allowable working pressure of Z under 250℃. When the operating temperature increases, the pressure resistance of the valve body will decrease. For example, a carbon steel control valve with a nominal pressure of 6.4MPa (PN64) has a pressure resistance of 5.2MPa at 300 ° c, 4.1MPa at 400 ° c, and 2.9MPa at 450 ° c. Therefore, the control valve nominal pressure should be determined not only according to Z high working pressure, but also according to Z high working temperature and material characteristics, not only to meet the nominal pressure is greater than the working pressure.
Performance testing of pneumatic ball valve
1. When a certain specification of pneumatic ball valve is manufactured in batches, an authoritative institution shall be entrusted to test the following performance:
Valve in the working pressure condition of the opening and closing torque;
(2) in the working pressure condition, can ensure the valve close close continuous opening and closing times;
The valve in the pipeline under the condition of water flow resistance coefficient detection.
2. The valve shall be tested as follows before leaving the factory:
Valve in the open state, the valve body should bear the valve working pressure value of twice the internal pressure test;
Under the closed condition of the valve, both sides bear 1.1 times the valve working pressure value, no leakage; But metal seal butterfly valve, leakage value is not greater than the relevant requirements.