Pressure regulating valves (sometimes also known as pressure regulators, pressure control valves or pressure relief valves) form part of an injection circuit that allow liquid to flow from a pump to a pressurized pipe.
Basic facts about pressure regulators
Pressure control valves are essential elements in systems where the inlet pressure is very high (generally higher than 4 bar). They are responsible for establishing and maintaining constant pressure in the system, acting as the main pressure relief device. In this way, inflow pressure stays constant with respect to outflow pressure (which can never be higher than the inflow pressure).
Pressure regulators are used in systems where continuous outflow is required while the pump is operating. They are also essential in pump-driven systems that do not require outflow from the nozzle.
Why are pressure relief valves important?
Let’s take the example of a house: the pipes that carry water inside the house have their own pressure gauge and a spring that pressurizes the diaphragm. If the pressure gauge reads very high —over the maximum recommended 4 bars— the water would circulate with so much force that many hydraulic circuits and devices that we have in our homes, such as the filling mechanism of the toilet tank or the faucets, would break.
Parts of pressure regulators
Pressure regulating valves are metal (usually brass) units with the following parts:
- Plunger with sealing gasket inside
- Pressure gauge ports, one on either side, to take the pressure in either direction
- Ring blocking the pressure regulating mechanism at the outlet
- Spring, which exerts pressure on the diaphragm (a rubber elastomer cover that moves up and down). The spring pressure is regulated manually using the adjustment mechanism on top.
- The internal part of the mechanism, consisting of two cavities through which water enters and exits and a sealing gasket at the bottom of the part that prevents water from escaping.
The operation of the valves is very simple.
When inlet line pressure is higher than outlet line pressure, the plunger in the valve body rises. Conversely, when the pressure drops, so does the plunger.
To regulate the outflow pressure, you adjust the pressure of the spring by turning the knob. As water pressure increases, it exerts more force on the spring, which then lifts the piston. Afterwards, it is closed off and the water pressure drops.
In any case, it is very important to keep an eye on the gauge while performing this operation so that the pressure does not exceed 4 bar, which is the maximum recommended.
Types of pressure regulators
There are two types of pressure regulating valves:
- Those that have an outlet port (which would be the connection to the tank), and therefore consist of three courses. They use the outlet port to lower the working pressure when it rises.
- Those that do not contain an outlet, and therefore consist of only two courses. In these cases, when the pressure rises to its optimal state, the course is closed off so that it does not increase any further. The only way to lower it is for the system to start working, and for this the elements must move.
Control valves in use
The question now arises as to what this type of industrial valve is used for.
This depends mainly on what they are to regulate: it is usually water, but can also be other substances such as compressed air, hydrocarbons or oils.
They are mainly used in:
- Protection of electric heaters for both hot water storage and household appliances
- Industrial applications
- Water and gas pressure regulation in buildings and domestic systems
- Flow limiters
- Water level control
- Low pressure irrigation systems, filtering stations and line filling control, among other things
At ULMA Forja we have been manufacturing different valve components for more than 30 years: body, bonnet, adapters, ball…. If you want to know what kinds of parts we can forge for your business, do not hesitate to contact us. Our tradition of excellence puts your mind at ease.