Gate valves
Gate valves for water, wastewater and Irrigation
What is a Gate valve?
Gate valves are used in various applications for controlling fluid flow. They are typically installed as isolating valves and are designed to be either fully open or fully closed. Gate valves are not suitable for controlling or regulating flow but excel in providing minimal pressure loss when fully open.
Key Features
Gate valves operate by rotating a stem either clockwise to close or counterclockwise to open. The valve features a threaded stem that moves a gate up and down to control the flow.When fully open, gate valves have no obstruction in the flow path, leading to very low-pressure loss and allowing the use of pipe-cleaning pigs. The slow, multi-turn operation helps prevent water hammer effects.
Applications
Potable Water & Wastewater
Operate efficiently within temperatures from -20°C to +70°C, with flow velocities up to 5 m/s and differential pressures up to 16 bar.
Gas
Suitable for temperatures from -20°C to +60°C, with flow velocities up to 20 m/s and differential pressures up to 16 bar.
Metal-Seated vs Resilient-Seated Gate Valves
Metal-seated gate valves utilize a traditional design featuring a conical wedge and angular sealing devices. While this design was once common, it is prone to wear from impurities such as sand and pebbles, which can eventually compromise the tightness of the seal over time. This wear and tear can reduce the effectiveness of the valve in maintaining a secure closure.
In contrast, resilient-seated gate valves are designed with a plain valve bottom and a rubber sealing surface. This innovative design allows the valve to conform to and seal around impurities like sand and pebbles, ensuring a reliable closure even if the valve encounters debris during operation. The rubber sealing surface maintains its effectiveness and integrity even after repeated use, providing a durable and consistent seal.
Stem Design : Rising vs Non-Rising
When it comes to stem design, rising and non-rising stems offer different advantages. A rising stem design features a stem that moves up and down in tandem with the gate, providing a clear visual indication of the valve's position. This type of stem is particularly useful for above-ground installations, where it also facilitates easier maintenance and greasing. However, it is not suitable for underground applications due to its vertical space requirements.
On the other hand, a non-rising stem design involves a stem threaded into the gate, which moves vertically within the valve body. This design is more space-efficient, making it suitable for both above-ground and underground installations. Additionally, AVK offers non-rising stem valves with optional position indicators, providing added convenience for monitoring the valve's status.