Decompression, pneumatic valve selection from the several aspects to consider

Reduced pressure pneumatic valve product category is more, air pressure pneumatic valve main function is to air pressure decompression and stability to a value, in order to regulate the pneumatic valve to obtain stable gas source power for regulating control. Reduced pressure pneumatic valve in the drinking water, fire water, and other industrial water supply system is of vital significance.



the working principle of a pneumatic valve, decompression

is reduced pressure pneumatic valve by adjusting, reduced the inlet pressure to a needed discharge pressure, and to rely on the energy of the medium itself, make a pneumatic valve outlet pressure automatic stable, from fluid mechanics point of view, the reduced pressure pneumatic valve is a throttling element, local resistance to change that by changing the throttling area, change the kinetic energy of the flow velocity and fluid, different pressure loss, so as to achieve the goal of decompression.



2 common classification of pneumatic valve, decompression

the reduced pressure of the pneumatic valve products is various, and the common on the market has the following three kinds:

1. Direct acting pressure pneumatic valve



direct acting pressure pneumatic valve by adjusting the spring pressure setting outlet pressure, outlet pressure using the diaphragm sensor changes, through the pneumatic valve opening and closing drive piston guide adjustment main pneumatic valve throttling area the size of the flow area, realize the function of reduced pressure regulator. This product is mainly used for steam piping, decompression voltage stabilizing role. Direct acting pressure characteristics of pneumatic valve is not installed in the downstream external sensing line. Direct acting pressure pneumatic valve is the smallest in three kinds of vacuum pneumatic valve, use one of the most economic, designed for low flow rate.

2。 Piston vacuum pneumatic valve



piston vacuum pneumatic valve by pneumatic valve after pressure control. When pressure sensor detected instruction pneumatic valve pressure, reduced pressure pneumatic valve pneumatic valve opening decreased; When they tested the vacuum pneumatic valve after pressure decreases, and reduced pressure pneumatic valve pneumatic valve opening, in order to meet the control requirements. This type of vacuum pneumatic valve guide the design of the pneumatic valve is similar to direct acting pressure pneumatic valve.

from the guide line of pneumatic valve pneumatic role on the piston, the piston to open the main pneumatic valve. If the pneumatic valve is bigger, cannot open directly, this kind of design will use open the pneumatic valve inlet pressure. Therefore, this type of vacuum pneumatic valve, compared with the direct acting pressure pneumatic valve, under the same pipe size, capacity and higher precision. With direct acting pressure pneumatic valve is the same, reduced pressure pneumatic valve internal pressure, external sensing line installation.

3。 Diaphragm pressure pneumatic valve



diaphragm pressure pneumatic valve is double diaphragm instead of afferent decompression of the pneumatic valve piston, the increase of membrane area to open a large pneumatic valve, main and under the same pipe size, its capacity than the afferent piston vacuum pneumatic valve is greater. In addition, the diaphragm is more sensitive to stress change, the accuracy is higher. The reduced pressure pneumatic valve is flexible, can use different types of pneumatic valve guide ( Such as pressure pneumatic valve, pneumatic valve, air temperature loading pneumatic valve, electromagnetic pneumatic valve or several kinds of pneumatic valve and form a complete set of applicable) 。

3, reduced pressure principle of type selection of pneumatic valve

& amp; 1. Clear vacuum pneumatic valve in the use of equipment or devices, determine the working conditions of pneumatic valves, such as suitable medium, working pressure, working temperature and so on;

& 2. With pneumatic valve connected to the pipe nominal diameter and connection mode: flange, thread, welding, etc. ;

& 3. According to the pipeline medium, working pressure, working temperature to determine the selected decompression and internal parts of the pneumatic valve shell material: cast steel, carbon steel, stainless steel, alloy steel, stainless acid-resistant steel, gray cast iron, malleable cast iron, copper alloy, etc. ;

& 4. Determine the operating way of vacuum pneumatic valve: manual, electric, magnetic, pneumatic or hydraulic and electric hydraulic linkage, etc. ;

& 5. Choose the type of vacuum pneumatic valve;

& 6. To determine the reduced pressure pneumatic valve type;

& 7. Reduced pressure of the pneumatic valve parameters; For automatic steam pressure pneumatic valve, according to different needs to allow flow resistance, discharge capacity, back pressure, etc. , to determine the nominal pipe diameter and the diameter of the pneumatic valve seat hole;

& 8. Selected decompression geometric parameters of the pneumatic valve: determine the structure and size, length, the flange connection open and closed after the size of the reduced pressure pneumatic valve height direction, connecting bolt hole size and quantity, the pneumatic valve installation dimensions, etc.