Definition of gate valve
A gate valve is a valve utilizing a gate, usually wedge-shaped, that allows fluid flow when the gate is lifted from the seat. Gate valves have less resistance to flow than globe valves, and always be used fully open or fully closed.
Working of gate valve
When the handle wheel is rotated in an anticlockwise direction, the steam and gate is moving in a downward direction. The fluid flow line and gate will be tightly located between the two seats. Hence there will be not any leakage of fluid through the valve once the valve is closed completely.
Types of gate valve
Gate valves are usually divided into two types: parallel gate valve and wedge-shaped gate valve.
1. Parallel side gate valve: The parallel gate valve uses a flat disc gate between two parallel seats (upstream and downstream). Parallel gate valves are used in situations with low pressure drops and low pressures, and where tight shut-off is not an important prerequisite.
2. Wedge-shaped gate valve: Wedge-shaped gate valves use two inclined seats and a slightly mismatched inclined gate, allowing for tight shut-off. Solid wedges are the most common because of their simplicity and strength. They can be installed in any position, are suitable for almost all fluids, and are practical for turbulent flow. Flexible wedge gate valves are commonly used in steam systems. The disk is one piece with a cut around the perimeter to improve the ability to match error or change the angle between the seats.
Applications of gate valve
Gate valves are designed for fully open or fully closed operation. They are installed in pipelines as isolating valves, and should not be used as control or regulating valves. The operation of a gate valve is either turning the handle clockwise to close or to open. Gate valves are used with almost all fluid such as air, fuel gas, feedwater, steam, lube oil, hydrocarbon. Some special gate valves are used in slurry and powder products too, such as knife gate valve.
Advantages of gate valve
1. Gate valve provides good pressure drop during operation.
2. Most of the gate valves can be used as bi-directional valves.
3. They are suitable for high pressure and temperature application and require low maintenance cost.
A gate valve is a valve utilizing a gate, usually wedge-shaped, that allows fluid flow when the gate is lifted from the seat. Gate valves have less resistance to flow than globe valves, and always be used fully open or fully closed.
Working of gate valve
When the handle wheel is rotated in an anticlockwise direction, the steam and gate is moving in a downward direction. The fluid flow line and gate will be tightly located between the two seats. Hence there will be not any leakage of fluid through the valve once the valve is closed completely.
Types of gate valve
Gate valves are usually divided into two types: parallel gate valve and wedge-shaped gate valve.
1. Parallel side gate valve: The parallel gate valve uses a flat disc gate between two parallel seats (upstream and downstream). Parallel gate valves are used in situations with low pressure drops and low pressures, and where tight shut-off is not an important prerequisite.
2. Wedge-shaped gate valve: Wedge-shaped gate valves use two inclined seats and a slightly mismatched inclined gate, allowing for tight shut-off. Solid wedges are the most common because of their simplicity and strength. They can be installed in any position, are suitable for almost all fluids, and are practical for turbulent flow. Flexible wedge gate valves are commonly used in steam systems. The disk is one piece with a cut around the perimeter to improve the ability to match error or change the angle between the seats.
Applications of gate valve
Gate valves are designed for fully open or fully closed operation. They are installed in pipelines as isolating valves, and should not be used as control or regulating valves. The operation of a gate valve is either turning the handle clockwise to close or to open. Gate valves are used with almost all fluid such as air, fuel gas, feedwater, steam, lube oil, hydrocarbon. Some special gate valves are used in slurry and powder products too, such as knife gate valve.
Advantages of gate valve
1. Gate valve provides good pressure drop during operation.
2. Most of the gate valves can be used as bi-directional valves.
3. They are suitable for high pressure and temperature application and require low maintenance cost.
Disadvantages of gate valve
1. It cannot be used to control the flow.
2. A gate valve is slow in operation. Opening and closing take times which is good as it reduces the chance of hammering.
3. When partially open, it creates vibration and noise.
4. Repairs, such as lapping and grinding of seats are more difficult due to limited access.
Next: Types of Gate Valves