What are the parts of a gate valve?
A gate valve consists of a valve body, seat and disc, a spindle, gland, and a wheel for operating the valve. The seat and the gate together perform the function of shutting off the flow of fluid. A typical gate valve is shown in Figure 12.9.
What are the different types of gate valves?
Gate valves can be divided into two main types: Parallel and wedge-shaped. The parallel gate valves use a flat gate between two parallel seats, and a popular type is the knife gate valve designed with a sharp edge on the bottom of the gate.
How do you open a gate valve?
The proper way to open a gate valve is to gently turn the handle counter-clockwise (to the left) without applying excessive force – do not ‘jerk’ the handle. A typical 1″ main control valve for a water line will take about six full turns to fully open. Stop turning as soon as there is any resistance.
How do you identify a gate valve?
The gate can be shaped like a wedge, knife, or parallel. Physically, gate valves are higher than globe valves when fully opened, but have a smaller face to face length. The gate being moved up or down is easy to visually acknowledge as the valves operate with either a rising stem or a non-rising stem.
What is bonnet in gate valve?
A bonnet protects the internal parts of a gate valve (Figure 2). It is screwed in or bolted to the valve body, creating a leak-proof seal. Therefore, it is removable for repair or maintenance purposes. Depending on applications, gate valves can have screw-in, union, bolted, or pressure seal bonnets.
How do you know if a gate valve is open or closed?
When the handle is parallel to the valve, it is closed, and when it is perpendicular to the valve, it is open.
Can gate valves be repaired?
A malfunctioning gate valve is not difficult to repair, but it is even easier to prevent. These problems are typically caused by mineral buildup, so you should fully close and open your gate valves every few months to clear potential problems.