Gate valves are one of the most common valves used as a main shut off valve. They are reliable and long-lasting. Gate valves have a twist-type handle and should only be used to fully open water supply or completely shut off water supply.
Ball valves are the most commonly used shut-off valve. Popular for their speed, reliability, and durability, ball valves are widely used in residential and industrial applications to turn the water on and off without a pressure drop.
Large water supply lines use gate valves due to their straight flow path and less flow restrictions. Ball valves are increasingly used in new plumbing systems with frequent shut off requirements. Gate valves are used for application with slurries and viscous media because they are easier to clean and maintain.
Gate valves are best suited for applications that require infrequent operation and small installation space. Ball valves are ideal for applications that require fast cycle times, multiple ports, reliable, tight seals and/or frequent operation.
Application: Ball valves are typically better for applications where a tight seal is necessary, such as in water or gas lines. On the other hand, gate valves are better for applications where a large amount of flow is needed, such as sewer lines. Ball valves are also typically easier to operate than gate valves.
Ball valves may be the most reliable valve and are commonly used for main water shut offs.
Ball Valve
These valves tend to be more reliable than gate valves and are not prone to leaking or seizing, however over time they do not allow for the same precise control over the flow of water as a gate valve. Ball valves consist of a lever that can be rotated just 90 degrees.
Ball valves are durable, performing well after many cycles, and reliable, closing securely even after long periods of disuse. These qualities make them an excellent choice for shutoff applications, where they are often preferred to gates and globe valves.
Installing a Ball Valve as the main shut off
Having a ball valve will help you save thousands of dollars in case of a leak, simply put, if you have a gate valve you're at risk of major damage. Ball valves are easier to operate, you can clearly see in what position the handle is and know if your valve is open or shut.
The initial cost savings of a plastic valve over metal is obvious, but additional cost savings are incurred with lower costs to install, reduced freight, maintenance costs and a longer service life of the valves. Plastic valves, on average, out-perform metal valves and have maintenance free service.
Disadvantages of gate valves
High friction and erosion: When used over time, the sealing faces of gates valves can erode or become damaged. During the opening and closing of the valve, there is a high level of friction between the contact sealing faces, causing erosion damage or scratches to these sealing surfaces.
Gate valve is the most widely used type of valve in plumbing systems. It includes a wedge-shaped metal gate that can be lowered (with the use of a twist-type handle or knob) to stop the flow of water or raised to allow the flow to continue.
Ball valves are simple and durable, making them a popular choice for plumbing applications. One of the most common uses for ball valves is to regulate water flow. This is often done by installing a ball valve at the end of a water line.
Any valve in the heart can become diseased, but the aortic valve is most commonly affected. The other common type of heart valve condition happens when the opening of the valve is narrowed and stiff and the valve is not able to open fully when blood is trying to pass through; this is called stenosis (Figure 2).
The aortic valve is the most common valve to be replaced. The mitral valve is the most common valve to be repaired. Only rarely is the tricuspid valve or the pulmonic valve repaired or replaced.
A ball valve is better suited for on-off applications than it is for regulating flow. The same goes for gate and piston valves. For flow regulating, globe and butterfly valves are preferred choices, with globe valves being especially common.
Disadvantages of ball valves
They are not suitable for slurry type applications due to cavities around the ball and seats. Slurries or other thick liquids tend to solidify or clog inside of the cavities, greatly increasing the operating torque of the valve and in some cases rendering the valve inoperable.
There are a few potential ball valve failures like getting stuck, fluid leakage, corrosion, and overheating, due to which the valve may not function properly. It is possible to troubleshoot these issues rather than replacing the valve entirely in most cases.
Ball valves have several advantages over other industrial valves, with the most notable being: They provide leak-tight seals. They can open and close quickly. They are more durable than most other industrial valves.
Many ball valve manufacturers provide an estimate of expected ball valve lifespan (usually eight to 10 years), and proper maintenance can certainly extend this range. However, ball valve lifespan can be influenced by a variety of other factors.
A typical 'generic' failure rate source puts the ball valve failure rate at between 0.2 and 10 failures per million hours, or one every 11 years.
So, can a ball valve reduce water pressure? Due to the fact that a ball valve should only be fully open or fully closed, it is not advisable to use a ball valve to control pressure. For this application, it's always best to use a pressure reducing valve, also known as a pressure regulator.
Four common failures associated with automatic valves are found at a high frequency in poorly performing control loops. These are Dead band, Stiction, Positioner overshoot, Incorrect valve sizing, and Nonlinear flow characteristic.