Both ball valves and check valves are valves necessary in plumbing applications for better fluid control with the various applications.
However, there are various differences between the two valves in terms of function, symbol, advantages, limitations, design, principle, and applications. Below is a detailed description of each valve with a clear outline of their differences.
What is Ball Valve?
A ball valve is a device designed to control, stop, or allow the flow of fluids and gases through a given piping system. The ball at the center of the valve has a bore that allows fluid or gas flow. Depending on the intention of ball rotation, the flow can stop or flow partially or fully.
What is a Check valve?
A check valve or a one-way valve refers to a device that allows fluidic/gaseous materials to flow through it in just one direction while preventing reflux. Upon reverse flow, the check valves close and stop it.
Function
Ball Valve Function
A ball valve makes use of a ball with a bore at its centre which allows a full flow of the fluid when fully aligned with the flow inlet. When the bore is partially aligned with the inlet flow, the fluid flow is partially restricted.
This partial restriction allows for better control over the flow rate, making it ideal for applications that require precise regulation. When the ball is quarter-turned and the bore is out of line with the flow inlet, the flow is completely blocked.
Check Valve Function
The main function of a check valve is to prevent the back or reverse flow of fluids or gases in various applications.
A forward flow fully opens the valve and a fluid can flow through it unstopped. However, when a reverse flow occurs, the check valve is completely closed hence preventing the back flow.
Valve Symbol
Ball Valve Symbol
A ball valve is given a symbol with the shape of a bowtie and an outline of a ball at the center as shown in the picture below.
The two triangles facing each other show a forward and a backward flow in the system. An outline of a ball at the center shows that the ball can freely rotate to control fluid flow.
Check Valve Symbol
The check valve symbol has two straight lines at both ends, a triangle at the center, and a vertical line to the right side of the triangle as shown below.
Two horizontal lines at both ends show an inlet and outlet flow. The triangle is pointed towards the right side and the vertical line shows a forward flow with no reverse.
Advantages
Ball Valve Advantages
Ball valves can handle high-pressure fluid flow situations better than check valves can hence suitable for applications that involve high pressure.
The operation of a ball valve is easy, simple, and fast with requires just a turn of a wheel.
A ball valve also lasts longer with low maintenance requirements and offers a tight shut-off possibility for different high-pressure applications.
Ball valves are applicable in various fluid or gas flow systems from residential to commercial plumbing applications.
Check Valve Advantages
A check valve is capable of maintaining a unidirectional fluid flow for various applications.
Since the backward flow is not allowed by check valves, they help maintain the system pressure.
Usually, these flow control valve systems are also easy to install with minimal maintenance requirements compared to other valves.
A plumber can use check valves for both horizontal and vertical fluid flow systems and for backup cases.
Limitations
Ball Valve Limitations
A ball valve needs proper installation and if not installed properly or when damaged, it can remain in the open or shut situation causing serious plumbing issues.
We said earlier that a ball valve can control the fluid flow, however, it offers limited control capability which may lead to overflows or leaks in the system.
The ball valve being a closed system may prove hard to fix when something damages its body or the seal.
Ball valves are not suitable for applications that require a series of rapid directional changes in fluid flow.
Check Valve Limitations
Check valves are prone to damage due to water hammer when the fluid or gas flow is abruptly interrupted.
When a check valve fails due to damages, various problems can occur including pressure loss and flooding.
Check valves are relatively expensive because they are made of expensive materials like stainless steel.
Regular maintenance and replacement are a requirement for check valves which could lead to more expenses.
Design and Structure (Compare Various Parts)
Ball Valve Parts
Generally, a ball valve is made up of six main parts as listed below.
The body – A central part that houses all the components of a ball valve usually made of metal, plastic, or metal with ceramic.
Ball– An object having a center apex, so that fluid or other materials may pass through a pipeline.
Seats – These are discs placed on every side of the body to support the ball and connect with the body.
Stem – The section of the valve that links the ball with the control system, externally controlled by say lever or handle.
The Power Source electric/hydraulic/pneumatic power source is employed to drive the ball valve movement.
Packing– A seal is placed around the stem to ensure that the fluid does not escape.
Check Valve Parts
Check valves are basically made up of four main parts. However, different types of check valves have additional unique parts.
Valve body – The component that holds all the check valve parts together and through which the fluid or gas flows.
Inlet port – The fluid enters the valve through the inlet port from the mainstream.
Valve closure element – The component that closes or opens the inlet port of the valve.
Outlet port – Fluid or gas leaves the valve via an outlet port located at the far end away from the inlet port.
Working Principle
Ball Valve Working Principle
The ball with a bore can rotate within the valve. However, in order to rotate the ball, a lever or a handle is used to move the stem which in return sets the ball into motion. The rotation of the ball can either close, open or partially open to either stop or allow fluid or gas flow. When the ball rotates to 90 degrees clockwise, the fluid flows freely and is interrupted. When the ball rotates 90 degrees anticlockwise, the fluid flow is stopped completely.
A throttling flow can also be achieved when the ball valve is partially closed and partially opened for fluid flow control.
Check Valve Working Principle
A check valve works by opening and shutting the valve to allow or stop the fluid or gas flow through it. For the valve to open and allow a forward flow, it depends on the minimum upstream pressure offered by the flowing fluid. If the pressure at the inlet is greater than the one at the outlet, the valve opens and the fluid flows through it.
When the pressure at the outlet is greater than the inlet pressure or if the fluid tends to flow backward, the valve is shut to prevent the backward flow.
Application
Ball Valve Applications
Oil and gas systems – Ball valves are mainly used in this industry for functions such as isolation for cracking units, meter or measure fluid or gas distribution.
Pharmaceutical industry – Sanitary ball valve types are mostly used in the pharmaceutical industry.
Petrochemical industry – Since ball valves can work with highly viscous fluids, they are also used in petrochemical systems.
Water piping systems – Ball valves are also suitable for various water supply systems.
Other applications for ball valves include food, irrigation, car washing, and the automotive industry.
Check Valve Applications
Sewage systems – A check valve ensures that there is no reverse fluid flow in these systems hence not waste goes back to the pit.
Pump systems – A reliable unidirectional fluid flow control system protects the pump and the piping system from damage.
Heating systems – Check valves also prevent water flow back into the radiation units in various heating systems. They also prevent hot water from flowing through the pipes when it is meant to stop.
Water treatment plants – Check valves to prevent recontamination of water by preventing reverse flow.
Conclusion
Various applications may require both the ball and check valves in order to achieve optimal function within the systems. However, you need to consider various aspects including system requirements, fluid type, pressure requirements, fluid control requirements, etc.
Generally, ball valves are good for tight shut-off, on/off, and quick operation applications while check valves are good for backflow prevention, and unidirectional flow applications.
