At Valfonta, we are dedicated to the manufacture and development of mechanisms to control pressure, guaranteeing greater effectiveness and efficiency in distribution systems and installations where fluids of different characteristics circulate.

Our speciality is pressure reducing valves, as well as relief valves, and we can even manufacture them to measure for each system or installation.

The use of regulating valves is essential, not only to control the pressure, but also to avoid damage to the piping or possible leaks and losses of fluids and gases. In distribution networks, there are areas where the pressure is high, either because they are close to pumping stations or because they are geographically located in sectors of low elevation.

This is when it becomes necessary to reduce both the pressure inside the system — since, if this is not done, a perforation may occur in the pipes due to the excess — and to prevent leaks of any fluid circulating inside the system.

What is the function of the pressure reducing valve? 

The pressure reducing or regulating valve is a fluid control valve, whose main function is to reduce the outlet pressure of the system, regardless of variations in inlet pressure or demand in the line.

At Valfonta, we have been manufacturing and designing this type of pressure regulating valves for fluid systems for more than fifty years, and they are our main speciality. In this sense, the experience we have acquired over all these years is the best guarantee for each of our customers.

We study each installation carefully, as well as the needs or requests made to us, until we find the optimum solution and the most suitable valve.

Features of the pressure relief valves S1 and S2:

In this post, we will show you the characteristics and differences between two of our most common pressure relief valve models, the S1 and S2 models. These are only two options of our wide catalogue of valves, do not hesitate to ask for more information, as well as personalized advice to choose your valve, if you need it.

S1 valve

It is a self-operated excess pressure valve. This series of regulating valves is suitable for steam, compressed air, non-hazardous gases and liquids. It has a very fast response to demand. It has a globe valve, single-seated. The stem is sealed by the double-layer bellows.

It is made of stainless steel; to avoid any damage to the bellows, the S1 series is provided with an anti-rotation system. An intermediate gasket enhances the diaphragm. Regulating range 0.5 and 15 barg with different actuators. The valve opens when the upstream pressure increases. Maximum inlet pressure 15 barg.

Other configurations: 

  • kV or reduced CV.

  • A control line kit to touch the pressure directly at the body (optionally with or without condensing tank) for set points > 1 barg.

  • Condensation tank (pot) is available and is required for steam or fluids with a temperature above 125 °C, to protect the diaphragm against excessive temperatures.

válvula de exceso de presión autorreguladora

S2 Valve

Self-regulating excess pressure valve. The main function is to maintain the inlet pressure at a set maximum value — relieving excess pressure downstream — via the regulating shaft. When the inlet pressure rises above the set value, the valve opens proportionally to the detected pressure increase.

This type S2 pressure regulator is suitable for low-temperature steam (with condensing tank), compressed air, gases, and liquids. The actuator is fitted with a diaphragm with a high quality reinforcing diaphragm fabric. Its inlet pressure regulation range is from 0.02 to 10 barg with the different actuator sizes.

válvulas de exceso de presión autorreguladoras

The condensation tank is available and is necessary when the fluid is steam or for liquids with a temperature above 125 °C, to protect the diaphragm from overheating.

It is important to mention that the excess pressure valve is not a safety valve and, when necessary, an overpressure protection must be installed.

The applications of this type of valve is that it allows a zone with excess pressure to feed another zone with lower pressure, without the main line being de-supplied. In case of excessive consumption, it prevents overpressure.

As we can see, pressure valves are designed to reduce and stabilize the pressure of a fluid. They are primarily conceived as a pressure compensation system that seeks to minimize the variation of the outlet pressure.

The benefits of these self-regulating pressure valves are related to stabilizing the pressure in all types of systems, preventing high pressures from generating cracks, vibrations, noises in the pipeline, pressure variations at different times of the day… Control valves, if chosen and maintained in the right way, increase efficiency, safety, and profitability.

To contact our sales department, simply fill in the form below, call 933 72 08 88, or email Together, we will find the most suitable valve for your system or installation!