Foot Valve
What is a Foot Valve?
A foot valve is a type of valve that is installed at the bottom of a pump inlet pipe. It is a one-way valve that allows water to flow into the pump, but not back out again. By preventing the water from flowing backwards, it prevents the pump from having to constantly prime itself due to lost suction. Foot valves are most commonly used in submersible pumps because they need to maintain steady pressure in order to operate properly.
How Does a Foot Valve Work?
A foot valve is essentially a check valve that works off of gravity. The valve is designed so that when the pump is off, the gravity-powered valve divides the pipe in two, ensuring no water flows from the top of the pipe to the bottom. When the pump is turned on, the pressure of the water causes the valve to open, allowing water to flow into the chamber. This allows the pump to fill up with water and build pressure, which is how it works.
Why Do You Need a Foot Valve?
A foot valve is necessary because of the way submersible pumps work. When the pump is off, gravity pulls water out of the pipe, which creates a vacuum. This means that when the pump is turned on, it will not be able to build up the pressure it needs to operate in order to draw water up the pipe - it has to first fill the pipe with water before it can build the pressure. A foot valve prevents the vacuum from forming and ensures that the pump retains its prime. This is the main reason why foot valves are necessary.
Types of Foot Valves
There are two main types of foot valve: swing check valves and flap valves. Swing check valves are usually made of metal and are the most common type of foot valve. Flap valves are made of rubber, plastic or other materials, and are a more lightweight option. Both types of foot valves serve the same purpose, but swing check valves are more reliable and are generally preferred for submersible pumps.
Summary
A foot valve is a type of valve that is installed at the bottom of a pump inlet pipe. It is a one-way valve that prevents the water from flowing backward, which prevents the pump from constantly having to prime itself. Foot valves are necessary because they ensure that water flows into the pump and build up pressure, helping the pump to start and run properly. There are two main types of foot valve - swing check valves and flap valves - both of which serve the same purpose, but with slightly different designs.