Difference Between API Gate Valve and Butterfly Valve

API Gate Valve vs. Butterfly Valve

Both gate and butterfly valves are two very common valves. The two have great differences in their own structure and usage methods, and in adapting to working conditions. This article will help users to better understand the difference between gate valve and butterfly valve, so as to better help users to select the valve.

Gate valves: this valve is designed to start and stop the flow of water. It is named for the way that the stopper drops like a gate. The design offers little resistance, and fluid flows unimpeded through the valve. One last thing, gate valves can be set in any directional flow.

Butterfly valves: this valve is designed to start, stop, and regulate the flow of water. It's named for the rotating disc that opens and closes the valve. Because you can partially open the valve, you can control the flow of water. One weakness is that it suffers from pressure drop.

What is a Butterfly Valve?

Butterfly valves, or also referred to as flap valves, are composed of a fixed disc on the stem of the valve which is used for opening and closing the valve. This disc rotates around the valve’s stem so that the flow of the medium can be regulated in the system. To open or fully close, the valve’s disc requires a 90° rotation.

These types of valves can be used for either regulating or isolating a media flow with ease of control. However, butterfly valves are associated with leaving residual materials inside of the pipelines.

Butterfly Valve Advantages

Affordable in large sizes
Can easily control the flow easily and suitable for throttling fluids
Fast operation time – ideal for emergency shut-offs
Lightweight and compact designs
Suitable for use with moderate to high temperature and pressure conditions

Butterfly Valve Disadvantages

Likelihood of water hammers
Movement of the disc is unguided so can be affected by flow turbulence
They leave resisdual materials in pipes
Thick liquids can prevent disc movement
Thickness of the valve’s body creates resistance which will obstruct flow and cause pressure drop even when fully open

What is a API Gate Valve?

api Gate valves, or also referred to as sluice valves, cut off the flow of the medium in a pipeline by lifting a rectangular or round gate from the medium’s flow path. The gate’s directional movement is perpendicular to the flow of the medium, and they’re sometimes known as cut-off valves.

These types of valves are used when there is a desire for minimum restrictions and uniform linear flows. They can either be completely open or completely closed, which will not allow for the adjustment of the medium’s flow. Due to this, the medium’s discharge is typically complete and there are no residues left in the system’s pipes.

API Gate Valve Advantages

Allow uniform linear flows and are bi-directional
Can provide an unobstructed flow in the fully open position so pressure loss is at an absolute minimum
Can withstand higher pressures compared to butterfly valves
No residues left in pipes
Prevent water hammer due to wedge slow operation

Gate Valve Disadvantages

Can only be completely open or completely closed with no adjustments for the flow allowed
More expensive in larger sizes than butterfly valves
Operation speed is slow due to the gate valve’s high opening height
They occupy a larger space for the installation and operation compared to butterfly valves
Valve’s seat and gate will erode badly if kept in partially open state

Understand the definition of gate valve and butterfly valve, the following describes the difference between gate valve and butterfly valve:

1. The difference in athletic ability

In the above definition, we understand the difference between the movement direction and the movement mode of the gate valve and the butterfly valve. In addition, since the gate valve can only be fully open and fully closed, the flow resistance of the gate valve is smaller in the fully open state; In the fully open state, the thickness of the butterfly valve creates resistance to the flow medium. In addition, the opening height of the gate valve is high, so the opening and closing speed is slow; and the butterfly valve can be opened and closed only by rotating 90°, so the opening and closing is rapid.

2. The difference between function and use

The sealing performance of the gate valve is good, so it is often used in pipelines that require strict sealing and does not require frequent repeated switching, and is used to cut off the circulating medium. The gate valve cannot be used for regulating the flow rate. In addition, because the opening and closing speed of the gate valve is slow, it is not suitable for the pipeline that needs emergency shutoff. The use of butterfly valves is relatively more extensive, and the butterfly valve can not only be used for truncation, but also has the function of adjusting the flow rate. In addition, the butterfly valve opens and closes quickly, and can also be frequently opened and closed, especially suitable for occasions requiring quick opening or cutting.

Butterfly valves are smaller in size than gate valves and lighter than gate valves, so in some environments where installation space is limited, a more space-saving wafer type butterfly valve is recommended. Among large-diameter valves, butterfly valves are the most used, and butterfly valves are also recommended for transporting medium pipes containing small particles of impurities.

Butterfly valves have gradually replaced other types of valves in many operating conditions, making them the first choice for many users.

3. The difference in price

Under the same pressure and the same caliber, the price of the gate valve is higher than that of the butterfly valve. However, the diameter of the butterfly valve can be made very large, and the price of the large-diameter butterfly valve is not cheaper than the gate valve.

4.The difference in Uses

Butterfly valves are found to be installed in larger pipe diameter systems as they’re more convenient to operate and are lighter compared to gate valves. They are ideal for installations that have limited space and applications that require quick opening and closing, especially emergency shutoffs. Butterfly valves can also be used to adjust or throttle flow rates.

They are generally referred to as high-performance valves because they suit applications that are under high temperature and pressure conditions, as well as suiting use with pipelines that contain small impurity particles.

Gate valves are better suited to applications that require strict sealing but do not need as frequent switching between open and closed. They cannot be used for regulating or throttling because it is impossible to achieve accurate control with them.

Gate valves should not be used for pipelines that require emergency shutoffs, because their opening and closing speed is quite slow, and if they’re left in a partially open position they will erode rapidly. If pressure is the main concern, gate valves can withstand higher pressures than butterfly valves and so, they would be the better choice.

They are commonly found in systems that require uninterrupted bi-directional flow or in time-based uni-directional media discharge applications.