Gate valves, also known as Multi-Turn valves, are the type of valves specifically designed for underground and above ground applications. The application and the installation will be either fully closed or fully open. The gate valves have slow opening and closing operations as you need to turn the valves multiple times to close or open them. Hence, there is no risk of the water hammer effect. As there is no obstruction in the passageway, the pressure loss is low. The gate valves can be placed on both sides of the gate as they are bidirectional. This mechanism provides good sealing and will prevent any block in the valve. You can also fit the gate valve at the end of the pipeline for tight sealing.
You need to note that gate valves should not be used as regulating or control valves. It is mostly used as an isolating valve for pipelines. Gate valve manufacturers in India insist that you need to be careful while choosing valves for underground applications. If the installation goes wrong, the cost of replacement will be exorbitant.
The design variations and body types pave the way to different types of gate valves. You need to understand each of them to know which one to use for your project. Gate valves are divided based on the body style, seating and stem.
The two main types of gate valves based on their body style are:
The two main gate valves based on the seating design are:
Metal seated gate valves
Metal seated valves have an angular sealing and a conical wedge with a metal seat. These valves require a depression at the bottom of the valve for tight sealing. If used for underground applications, the bores may fill with pebbles and sand. Hence, the piping system will be filled with impurities no matter how many times you flush the pipe. Eventually, the metal wedge will lose the tightness of its sealing.
Resilient seated gate valves
Resilient seated valves have a rubber surface made of Industry graded rubber component to absorb impurities and a plain valve bottom that allows pebbles and sands to pass freely around the valve. When the valve closes, the impurities that pass through the valve will be absorbed by the rubber surface. When the valve opens, the impurities will flush away. As you open and close the valve, the rubber surface changes and comes back to its original shape to provide a secure and tight sealing.
The two types of gate valves based on the stem design are:
Gate Valves With Rising Stem
Rising stem valves are most suitable for above ground applications. The threaded stem is fixed to the gate with a nut that allows it to lower and raise as you operate the valve in this design. It provides a better view of the valve and its position. You will also be able to grease the stem easily.
Gate Valves With Non-Rising Stem
The non-rising stems are placed inside the valve and rotate as you move the wedge. It is threaded to the gate and uses less vertical space.
Gate valves are used for applications that require a free bore and have a low-pressure loss. It is used in a wide variety of above and below the ground applications. It can be used with applications that handle fluids like water, potable water, neutral liquids and wastewater with varying temperature. You can also use gate valves with gas-based applications that have maximum flow velocity and varying temperatures.
We are the leading industrial valve manufacturers in India that manufacture and distribute quality machinery and Industry graded valves. For more clarity on valves, do contact us today.