Steel gate valves are mainly used as shut-off valves for pipelines where valve members are either in shut or open limit position.
These products are mainly used as shut-off valves for pipelines where valve members are either in shut or open limit position. They are used as auxiliary devices only in the existing open circuit hydraulic system with the nominal pressure of up to 1 atm.
Similar products are conventionally divided into groups that differ by the following properties:
• actuator type;
• actuator assembly position;
• types of valve connection to pipeline;
• trim type.
As mentioned above, gate valves are divided into wedge and parallel gate valves.
Types of steel wedge gate valves:
• rigid gate valve;
• split wedge gate valve.
Rigid products are designed with cast wedges that ensure good sealing. However, jamming can occur if the pipeline medium heats to high temperatures. This is caused by thermal expansion of the alloys. To prevent this from happening, a gate valve was designed with a split valve member consisting of two plates.
Gate valve is connected to the pipeline using standard bolted or welded flanges.
Gate valve is connected to the pipeline using standard bolted or welded flanges. The second method is considered to be more stable and safe. It is used in applications that involve corrosive liquids and high pressure of operating media. The valve ensures good tightness and prevents potential leaks through the sealing. Such gate valves have a small structural length. However, this should be dealt with in more detail when setting-up the valve or refurbishing the pipeline.
In terms of manufacturing method, the following gate valve types are differentiated:
• steel cast gate valves;
• steel welded gate valves;
• steel stamped gate valves.
Cast parts are the most widespread, as they are the most reliable pipeline elements. Their advantages consist in ease of use, low flow resistance, and small structural length. Among the drawbacks, one can mention long shutting/opening time and large height. This type of valves must not be used to control the speed of operating medium flow.