A balancing valve is a measurement and regulation device. Balancing valves are used in pressurized piping applications, such as HVAC and gas movement applications. A balancing valve uses a few key components in its construction to perform its function within the system.
The main purpose of a balancing valve is generally to create a consistent output pressure to a system from an inconsistent input pressure from a different system. This creates balance for the flow of the material being moved through the pressurized system as a whole. In most cases, these types of valves are also used as a means of creating a stable flow of material within an unstable system. Sometimes, to facilitate this purpose, the balancing valve must release a set amount of material if the pressure within the system builds too quickly.
Balancing valves generally must be made out of materials that will not respond in any way to the material being sent through them. This means a balancing valve must not rust, corrode, or build up residue from any material passed through it. Rather, the valves are basically passive valves that have a set of screws in them that determine the point when the valve must divert pressure from the system to an outside source.
As there is a great need for durability, these types of valves are often made out of brass or copper. They may also have silicon or rubber gaskets or o-rings located within them. The gaskets or o-rings help the valves seal correctly, should the valve need to be closed.
The valves often have an input opening that is offset slightly or greatly from its output port. This provides an instant resistance to the input material. The resistance helps the valve to create a consistent output flow.
There is usually also a pair of screws that project from one arm of the valve. These typically come out from the center of the unit at an angle perpendicular to the input and output of the valve. These two screws are adjustable, which allows them to determine the allowed input and output pressures of the material.
Opposite the pair of adjustable screws is typically a release valve. This acts as a burping vent for the material that passes through the system and is sent into the valve at too high a pressure. When the pressure determined by the screws is exceeded, the release valve opens long enough to allow enough material to escape without compromising the flow of the system.