Gate Valve

Table of Contents

What is a Gate Valve?

A gate valve, as the name suggests, controls media flow by lifting or dropping a gate. A gate valve is an on/off valve, meaning that it should only be used either fully opened or fully closed, and not to regulate flow, since the relation between the vertical position of the gate and the flow rate is non-linear [1]. In fact, operating in a half-open state could cause erosion of the disc and seating surfaces, as well as vibration and noise. Operation of the valve is done through a clockwise to close (CTC) or clockwise to open (CTO) rotational motion of the stem [2]. 

Advantages:

• Very little pressure loss [2]

• Open bore (open pathway - no obstruction of the flow path) 

• The open bore design also allows for the stem to be removed and valve to be easily cleaned

• Suitable for high pressure and temperature applications

• Bi-directional

• Require little maintenance

Disadvantages:

• No flow-regulating control [2]

• Slow in operation (this is also an advantage as it reduces chances of water hammering effect)

• Vibrations and noise when partially open

• Repairs are difficult due to limited access

Applications:

• Gate valves are mostly used in fluid applications: air, steam, lube oil, hydrocarbons, etc. They are also commonly used for liquids such as heavy oils, light grease, and other non-flammable liquids [3].

• Used in irrigation applications due to their ability to allow for a high flow rate, and slow operation is less important.

Gate Valves Types and Designs:

Many components of the gate valve can be used to sort the valve into different types. The following are some of the most common differentiations: