Selection of design parameters of the reverse flanged gate

The choice of the standard size of the flanged check valve is made taking into account the place of its intended installation, the type of working medium pumped through the pipeline, as well as taking into account the maximum permissible values of flow, pressure and temperature.

It should also be borne in mind that such a gate is more massive than a threaded one, and therefore in some cases causes additional load on the fasteners of the pipeline.

The impact of the working environment

In gas pipelines, flanged check valves, as distinguished by the most reliable seal, are very common. They are provided, in particular, when several gases are mixed into one gas stream. Check valves with flanges are installed on each of the individual gas streams to prevent mixing of gases before they enter the final pipeline.

Check valves of this design are also used in many liquid industrial systems, for example, in the chemical industry, nuclear and thermal power. In particular, in the nuclear industry, feed water control systems, discharge lines, monitoring and sampling systems are equipped with such return gates.

Since the presence of a flange and double strong gaskets significantly weakens the harmful effects of shock and dynamic loads, flanged valves are used in aviation devices where strong vibrations, extreme temperatures and chemically aggressive liquids are constantly present.

Design influence

Flanged check valves, characterized by the difference in threaded connections, increase the accuracy of their installation and subsequent operation, which does not depend on random factors (for example, on the degree of purification of the pumped working medium).

The high-precision valves are distinguished by the presence of an all-welded body, calibrated asymmetric spring and gaskets, which guarantees stable and silent operation.

For the correct choice of device parameters, a hydraulic calculation of all possible resistances affecting flow losses is pre-performed. For high-precision flanged valves, these losses should not exceed 10%.

Most standard sizes are designed for a maximum opening pressure of 6...8 kPa, with the highest possible requirements for the tightness of the structure.

When choosing, they are guided by the design and technical requirements for the production of flanged check valves, which are defined by GOST 27477-87. This standard sets the values:

• Maximum operating pressures;
• Conditional flow pressures;
• The temperature range of the pumped working medium, depending on the size of the conditional passage of the pipeline.