Cautions For Valves Selection

Valves introduced in this catalog are made of different designs and materials,and thus their specifications and characterisitics are not always identical.Careful attention must be paid to the following notes to appropriately select the valve you need:

Valve Specitictions

Field application of valves must be limited by specifications such as the maximum allowable service pressure and temperature,and the kind of line fluid to be handled.Carefully compare each of the indicated valve specifications with your intended service condition,before valve selection.Failure to do so could result in property damage and/or personal injury,for which Feiqiu Corporation shall not be liable.

Valve Materials

1, Valves made of grey iron,ductile iron or carbon steel casting will become rusty after prolonged contact to cold or hot water.Feiqiu stainless steel valves or rubber lined butterfly valves are recommended for water pipelines where rust must be prevented.

2, Pressure-temperature ratings of soft sealing materials such as rubber of PTFE seats employed for butterfly or ball valves are often lower than those of metariallic valve shell materials.

3, The kind of line fluid to be handled by soft sealing materials is severely restricted due to limted prosperities of soft sealing material employed for butterfly or ball valves.

Valve Design Characteristics

Gate valves:

Designed either for full release or complete block of line fluid.Throttling service with the valve partially open may cause damage to valve seating areas.

Full bore design provides the same cross sectional area through the valve opening for undisturbed fluid flow.A fully open valve features ultimately minimized pressure drop for high flow efficiency of the pipeline.

Fully closed valves show excellent sealing performance.

Globe Valves:

Designed for full release,complete block or partial release(throttling service) of line fluid.

Even a fully open valve is subject to high fluid resistance and resultant pressure drop is inevitable.Its flow efficiency is lower than that of a gate valve.

The fluid flow is uni-directional and valve installationmust be made according to the arrow mark provided on the valve exterior.

Check Valves:

For prevention of reverse fluid flow,the disc is designed to open or shut off,without extemal valve operating force,depending on the difference in the upstream and downstream pressures(differential pressure).

The fluid flow is uni-directional and valve installation must be correctly made according to the arrow mark provided on the valve exeterior.

Butterfly Valves:

Designed for full release,complete block or partial release (throttling service) of line fluid,by means of 90 stem rotation.Ldeal for efficient flow control.

Face-to-face dimensions are shorter than those of other valves,with the advantages of small installation space requirement and ease of installation.

Employment of rubber seats results in lower pressure-temperature ratings and limited choice of the line fluid to be handled.