Back Pressure Reducing Valve
Background of Back Pressure Relief Valve
Back Pressure Relief A valve is the kind of pressure control equipment that regulates a constant upstream pressure by discharging the superfluous pressure on a system. It is a safety and flow control valve that makes sure that pressure inside a pipeline, pump, or vessel does not surpass safe operating values.
A back pressure relief valve is a pressure relief valve, unlike a standard one, that opens when upstream pressure exceeds a setpoint to divert the excess fluid (liquid or gas) to a relief line, reservoir, or back to the system.
Typical uses include chemical processing, water treatment, pumping, pharmaceutical manufacturing, and gas handling, where the pressure of the system is important to system performance, safety, and equipment life.
Their main advantages are the protection of the system against overpressure, the maintenance of stable upstream pressure, and the avoidance of the destruction of sensitive equipment. They can be in different materials and arrangements to deal with corrosive fluids, high temperatures, and changing flow conditions.
Principle of Working of a Back Pressure Relief Valve
A back pressure relief valve (sometimes known as a back pressure regulator) is a safety or control device used to control and relieve excessive upstream pressure in a process system to maintain a predetermined setpoint of upstream pressure in a process system.
How It Works
Normal Operation
At regular pressure the valve is closed or slightly open so that fluid (liquid or gas) is retained in the upstream system.
Pressure Build-Up
When the inlet (upstream) side pressure rises as a result of the flow being restricted, or due to system conditions or process buildup, the internal spring-loaded or diaphragm mechanism detects this increase.
Setpoint Reached
The force created by the pressure becomes greater than the spring force when the pressure upstream is more than the preset value, and the valve opens.
Relief Action
The valve is opened slightly to relieve back pressure by bleeding off excess pressure to a downstream line or a return line (a tank or a drain).
Pressure Stabilized
When the pressure reduces below the set point, the spring force closes the valve once again and maintains controlled system pressure.
Uses of Back Pressure Relief Valve
A Back Pressure Relief Valve is a valve that will hold a constant upstream pressure by releasing excess pressure within a piping or processing system. It is essential in safeguarding equipment, process stability, and making the system more efficient.
The following are the major areas of application
Chemical and Petrochemical Plants
Applied to stabilize upstream pressure in reactors, pipelines, and dosing systems. Aids in avoiding breakage of equipment and accurate control of flow during chemical reactions.
Pump Protection
Fitted to the outlet of positive displacement pumps to avoid overpressurizing the system and causing it to fail because downstream flow is not free or is restricted.
Gas and Vapor Systems
Maintains the necessary pressure on the supply lines of gases and vaporizers, particularly in the distribution systems of compressed gases or natural gases, to avoid surge or underpressure conditions.
Water and Wastewater Treatment
Maintains proper backpressure on filtration systems, chemical dosing lines, and membrane processes such as RO systems to enhance the effectiveness of the process and prevent damage.
Pharmaceutical and Food Industries
Ensures clean and sterile operation through control of backpressure in CIP (Clean-in-Place) systems, liquid dosing lines, and sanitary pipelines.
Oil and Gas Pipelines
Prevents fluctuation of pressure in pipelines, metering systems, and storage tanks, as well as supports control valves to ensure safe and steady operation.
Sampling Systems and Instrumentation
Provides correct flow rates and measurements by sustaining consistent backpressure in analyzers, samplers, and pressure-sensitive devices.
FAQs
A BPRV is a protective device that allows excess pressure to be relieved by the escape of fluid when a predetermined back pressure is reached.
BPRVs are applied in chemical processing, water treatment plants, hydraulic systems, and other industries to safeguard equipment and balance systems.
Although both are pressure relief devices, a BPRV is used to regulate the pressure at the outlet side of a system (back pressure), and a standard pressure relief valve is used to regulate inlet pressure.
Back pressure regulators are used to provide stable flow, to protect the pumps, and to keep processes efficient by avoiding excessive over-pressurization of the system.
Depending on the fluid and application environment, they are typically manufactured of stainless steel or PVC or other corrosion-resistant materials.
When the valve is subjected to normal operating pressure, it is closed. The valve opens to release the pressure when back pressure is more than the set point and closes when pressure is normal.
The back pressure is sensed by a spring-loaded or diaphragm-operated mechanism, and the valve opens at the preset threshold.
Yes, the majority of BPRVs can be adjusted to the spring tension, so the required set pressure can be customised according to the requirements of the system.
No, it will only open when the back pressure is higher than the set point and automatically close when the pressure is below the threshold.
Yes, but the design of the valve and the materials used should be suitable to the media to operate properly and safely.
It is normally mounted on the outlet side of a pump or process unit, upstream of discharge lines or of important downstream equipment.
Most BPRVs are designed to be installed upright, although some designs will allow them to be mounted in a flexible position.
Properly align, do not over tighten, confirm the pressure rating of piping to valve, and keep the piping clean to avoid damaging the valve.
Yes, the isolation valves upstream and downstream are beneficial to assist in maintenance and testing without getting the entire system offline.
Yes, once installed, it is important to test and calibrate the valve to make sure that it will close at the right back pressure.
When it becomes worn, corrosive, de-calibrated, or leaky to the extent that this cannot be remedied by repair or replacement of parts.
Yes, metal or plastic components can be frequently separated and sent to relevant recycling centers depending on the material type.
Yes, provided the valve was used with hazardous and corrosive fluids, it should be decontaminated and disposed of as per the environmental safety provisions.
Keep a record of disposal with valve serial number, service history, material composition, and disposal method, particularly in regulated industries.
Yes, particularly with valves that have been exposed to dangerous materials, the decontamination and final disposal ought to be done by certified waste disposal services.
