The Difference Between Gate And Butterfly Valves

Two of the most popular valves on the market today are butterfly valves and gate valves, so let's explore what each type can do and what makes them such effective tools.

Gate valves come in many shapes and sizes but are often very large. Consider a valve that controls the flow of water in a main water supply line. Despite their sometimes enormous size, gate valves are designed to be controlled by one person.

Gate valve vs Butterfly valve

Butterfly valves can also come in many shapes and sizes. This valve also functions through the use of an internal gate. The difference between a butterfly valve and a gate valve is the way in which the gate valve operates inside the gate valve.

Unlike a gate valve, the gate inside the butterfly valve remains fixed and rotates around an internal axis. The shape of the inner gate rotating is where the butterfly gets its name.

Butterfly valves have the same function as gate valves, allowing and stopping the flow. However, both types of valves have their advantages and disadvantages, so it is important to keep this in mind when choosing either type of valve.

Butterfly Valve

Advantages and disadvantages of butterfly and gate valves

Pressure difference

Gate valves are usually better under pressure than butterfly valves. Their construction means that flow can continue to flow without any undue pressure fluctuations. And their use does not require much work.

This is not the case with butterfly valves. Their rotating gate configuration means that the fixed gate is subjected to a greater degree of differential pressure. This translates into the greater strength required to operate the butterfly valve. This can often be addressed by using longer arms to operate larger butterfly valves.

Wear and tear

Gate valves tend to outperform butterfly valves when it comes to durability. The gate valve design ensures that it does not suffer as much damage as a butterfly valve when it is in operation.

Even though higher pressure tolerances are taken into account when producing modern butterfly valves, the unfortunate truth is that butterfly valve design ensures a higher wear rate. Unlike gate valves, their seals are always directly exposed to the flow rate, whether the valve is open or closed. When activated, a portion of the gate valve is exposed to a very short time flow.

Gate Valve

Safety

This depends on the use of the valve and the pressure it may be exposed to. Skilled engineers who understand what these valves can and cannot do can avoid this problem altogether. Having said that, it is important to understand and accept that butterfly valves were not originally designed to handle the high-velocity flow. In fact, the safest recommended speed for this type of valve is 6 m/s. Anything above will subject the butterfly valve to dangerous pressure differentials, which will accelerate wear and could lead to premature failure and accidents.

High-Pressure Drop

Another issue affecting butterfly valves is the pressure drop at release. Today, the insistence on maintaining high pressure throughout the system to save energy is one of the reasons for the resurgence in the popularity of gate valves and other alternatives.

Cost

Butterfly valves tend to be cheaper than gate valves.

Size

Butterfly valves are smaller and more compact.  Often, this makes them more versatile in use than gate valves.

Both valves will act as a conduit for flow, rather than as a regulator. Neither is intended for continuous use. Once they are released, the flow is not regulated.