Pressure Reducing Valves

Materials Used

Types

Uses

A pressure reducing valve, a popular category of pipe valve, is used widely to reduce pressure in fluid flow, be it steam, air or gas or any kind of liquid. This type of pipe valve is also known as “Pressure Regulator”. It is a kind of throttling device. The pressure reducing valve gives a constant reduced pressure inspite of fluctuations, within reasonable limits and within the inlet pressure, that is the incoming high pressure.

The valves are made of various materials and are available in small, standard, high & super capacity models. They can be installed with required other accessories at places where complete station cannot fit. They are widely used in homes, commercial buildings, and manufacturing plants.

How does a pressure relief valve operates?
A pressure reducing valve automatically reduces the pressure from the water supply main to a lower and a more sensible pressure. When the water enters the valve from municipal mains, this is constricted within the valve body and it flows through the inner chamber which is controlled by an adjustable spring loaded diaphragm and disc. Even if the pressure of supply water fluctuates, the pressure reducing valve which is fixed ensures a constant flow of water at a functional pressure. This continues so long the supply pressure does not drop below the valve’s pre-set pressure.

Types of pressure reducing valves:
There are three basic types of pressure reducing valves. They are as follows:

• Direct-acting: This is the most simplest type of pressure relief valve. This type of valve operates with either a flat diaphragm or convoluted bellows. It is the smallest in size of all the three types and most economical. This type of valve is designed for low to moderate flows.
• Internally piloted piston-operated: This type of valve consists of two valves in one unit. They are the pilot and the main valve. The pilot valve is similar in design to that of the direct-acting valve. The discharge from the pilot valve acts on top of a piston and this opens the main valve.
• Externally piloted: In this type of pressure relief valve, the piston operator of the internally piloted design is replaced by double diaphragms replace. This diaphragm can open a large main valve, which in turn allows a greater capacity per line size than the internally piloted pressure relief valve. The diaphragms are also more sensitive to pressure changes. This type of valve also offers the flexibility to use different types of pilot valves.

Uses of pressure reducing valves:

• Pressure reducing valves are used by various pumping stations and water supply companies to ensure practical, working water pressures.
• Pressure reducing valves are used to boost water supply pressures in supply mains to be able-
  • to supply water for fire fighting
  • to supply water for high rise buildings
  • to overcome loss of pressure as the elevation increases, and
  • to maintain water supply in water towers and supply tanks
• Since high water pressures waste water, using pressure reducing valve helps in promoting water conservation , which in turn leads to water savings, energy savings, and wastewater savings.
• Higher pressures could damage fixtures, rupture pipes and injure the people using them. Hence, it is better to use pressure reducing valve.
• Gases, steam, liquids usually flow at high pressure to the points of final use. At these final points, a pressure relief valve lowers the pressure for safety and efficiency.