With the exception of parallel disk gate valve which includes parallel seats, all the other types namely, solid wedge gate valve, flexible wedge gate valve and split wedge gate valve have inclined V-shaped seats just like a wedge. The Wedge gate valve at https://stvvalves.com/ is among the most commonly used valve. This valve might be installed in any position.

A gate valve operates by moving a wedge shaped disc obstructer around to open and close the flow path over the valve. This linear motion is provided with a threaded rising stem. They should basically used for on/off applications as throttling with an extended length of time will damage both obstructer and seals. Use of a gate valve for throttling is additionally not very effective since most from the reduction of flow increase in the last 10% of closure.

Globe valves operate by using a convex disc shaped plug raise and minimize via a rising stem to a circular seat across the inside on the globe shaped body in the “equator”. The flow enters the “lower hemisphere” derived from one of side, then travels up over the seat and exits from the outlet for the opposite side from the “northern hemisphere”. Globe valves are suitable for both on/off and throttling applications. There are 2-way globe valves which can be a preferred option for precise flow control and 3-way globe valves that are popular for mixing media from two inlet ports and directing that mixture via an outlet port.

the discs have no choice but against the valve seats by way of a wedging mechanism because the stem is tightened. Some double-disc parallel seat valves require a design which depends mainly upon the fluid pressure exerted against one side with the disc or other due to the tightness. The major benefit from this type is usually that the disc can not be jammed in to the body, an action that will make it difficult to spread out the valve. This is particularly important where motors are employed for opening and closing the valve.

Unlike the wedge inside a wedge-gate valve, which only has contact nearly closed, each disc inside the parallel seat valve slides against its seat even though the valve will be opened or closed. Consequently, these ingredients must be crafted from metals, which don't gall or tear while in sliding connection with each other. The double-disc parallel-seat gate valve is usually favored for high-temperature steam service as it's less likely to stick within the closed position caused by change in temperature.