Pressure regulators and valves: what they are, how they work and how to choose them

What pressure regulators and valves are

A pressure regulating valve is the device that sets and maintains the desired working pressure at the pump outlet. It regulates the operating value and manages the flow that the outlet does not use. In the plunger pump world these are generally called regulating valves, while in agriculture, on diaphragm pumps, the term command units is often used, because the component also distributes the flow to the different sections of the boom.

The underlying idea is the same: without an element to govern the pressure, a volumetric pump would be effectively uncontrollable.

How they work

Operation revolves around two actions. The first is regulation proper: the valve sets the working pressure and, when the required flow is lower than what the pump delivers, it diverts the excess into a bypass circuit that returns the liquid to the inlet or the tank. This keeps the pressure steady at the set value instead of rising out of control.

The second action is protection. Many systems include a pressure relief valve, or safety valve, which trips when the pressure exceeds a critical threshold, releasing the liquid and shielding the pump and pipework from potentially serious damage. Regulation and safety can be built into the same component or handled by separate devices, depending on the system.

Why they are indispensable

The first reason is the protection of the pump and the whole circuit: an overpressure can break seals, hoses and fittings, causing costly downtime. The second is the quality of the work: a steady pressure means uniform delivery, whether it is the jet of a pressure washer or the boom of a sprayer. The third is the safety of the operator, because working with a pressurized system without regulating and relief devices is a real risk.

In short, the valve is not a detail: it is what turns a pump into a system you can actually use.

Valves for plunger pumps and units for diaphragm pumps

The two families of pumps have different needs. On plunger pumps, which work at high pressure, you need valves able to withstand very high values and handle large flows: the pressure regulators for this type of pump cover a very wide range, up to the most extreme pressures of industrial cleaning and water jetting.

On diaphragm pumps, typical of agriculture, modularity and section management matter more: the pressure control units include low, medium and high pressure regulators, designed for sprayers and treatment machines. The logic stays the same, but the component adapts to the setting.

How to spot incorrect pressure regulation

Recognizing when something is wrong in the regulation helps you act before the problem becomes a failure. A first sign is pressure surges: if the gauge swings sharply or the pressure struggles to stabilize, the valve is often not managing the bypass well. A second clue is premature seal wear: a pump forced to work at a higher pressure than needed quickly wears out gaskets and components.

Uneven delivery, with a non uniform jet or treatment, can also stem from imprecise regulation rather than from the pump.

Finally, if the relief valve trips frequently, it is a sign that the system is working too close to its limits and the sizing should be reviewed. Spotting these symptoms early extends the life of the whole system and reduces downtime.

How to choose them

The choice revolves around four parameters. The first is the flow rate of the pump: the valve must be able to handle the entire flow, including the share diverted to bypass. The second is the maximum working pressure: the component should be chosen to withstand the system pressure with margin, rather than working constantly at its limit. The third is compatibility with the pump and the application, because a valve designed for high pressure industrial use is a different thing from an agricultural command unit. The fourth is the materials in contact, which must resist the pumped liquid, all the more if it contains chemical additives.

One last practical tip: valve and pump should be chosen together, not separately. An undersized component limits the performance of even the best pump, and an overly generous one adds needless cost. You can start from the plunger pumps and diaphragm pumps ranges and, for the right pump and valve match, ask our technicians for an assessment based on flow rate, pressure and type of system.