A pressure relief valve does exactly what its name suggests. Valves like these are designed to keep a system at or below a safe pressure. As soon as the pressure in the system exceeds the safety setpoint, the valve releases the pressure. Excess material can be sucked into the atmosphere, recycled stream, bypass stream, or other methods.
The purpose of a PRV (pressure relief valve) is now clear to you. To help you choose one that’s right for you, let’s examine PRVs and their applications.
What Is the Purpose of a Pressure Relief Valve?
In ideal circumstances, a PRV aligned with your overall process won’t do much. However, these devices are desirable in the following situations:
- The system contains pressure-sensitive equipment.
- Due to construction materials and other process conditions, the process is pressure-sensitive.
- Safety of personnel.
- Fluids that are hazardous and need to be regulated could be released into the environment if overpressure is present.
Some or all of these restrictions apply to most industrial processes. Using PRVs effectively in your process means:
- Provides equipment and personnel protection.
- Provides effective operation of equipment in line.
- Reduces environmental and safety risks.
- Reduces downtime.
Different Types of Pressure Relief Valve
There are several types of PRVs, each with a different use case and functionality. Currently, we are focusing on their use in industrial applications. However, they are also commonly use in everyday plumbing applications. It’s no accident that chemical engineering is call an advanced plumbing degree.
To begin with, let’s distinguish between the different types of PRVs:
- When RVs (Relief Valves) open gradually, they act as pressure modulators. RVs are using in processes that involve non-compressible media.
- The SV (Safety Valve) is a strict open/close device. For immediate relief, it opens rapidly and releases overpressure fluids. As a result, the process environment and operators are kept safe. When compressible media is used, SVs are used.
- In both RV and SV applications, an SRV (Safety Relief Valve) is a PRV.
A Direct Acting Relief Valve, a Safety Valve, or a Safety Relief Valve
The direct operating valve is a self-operating valve. In contrast to other types, they do not require an upstream sensing line. In these devices, pressure is sensed directly through a bellow or diaphragm. Based on the set point of the valve and the pressure in the system, it opens or closes.
Pressure Relief Valves With Modulation
Overpressure modulates these valves. In contrast to a relief device that snaps open, these gradually open. Depending on the degree of overpressure, they seat themselves.
There are a variety of reasons why a modular relief valve may be desirable. For instance, sudden flow through a set orifice size might cause process issues. Modulating the fluid can prevent sudden phase changes or knock (cavitation) in the device. The importance of limiting emissions is another example. Only the minimal amount of media will relieve by a modulating valve to restore the system pressure to a safe level. With this type of valve, emissions are kept to a minimum.
Don’t get confuse by all this. Getting to know your process, safety requirements, and regulations is a great place to start. To specify an appropriate solution, a good company will work with your process. Many models come with an optional modulating pilot configuration, for example. This depends on the equipment manufacturer and distributor you are working with.
Emergency Relief Valves, Rupture Discs, and Hatches
A rupture disc is not a valve in the technical sense. In any case, they are well suite for this category and should be taken into account. There is nothing complicated about a ruptured disc. The rupture disc bursts when the pressure reaches the specified overpressure setting.
“Last resort” items are often use here. It is possible to protect critical and expensive equipment with rupture discs when other preventative measures fail. A ruptured disc may be a cost-effective solution if you don’t expect overpressure situations to occur often.
A vessel usually has an emergency relief valve and a hatch for emergency escape. When overpressure occurs, this can prevent the vessel from rupturing. When pressure exceeds expectations, it ensures relief capability. For accessing tank contents, gauges, and sampling, hatches are often specified.
That’s a lot of information to digest. Currently, you may feel like you could benefit from a PRV device. Trained, educated professionals can help you select the proper equipment.
Today’s main takeaways:
In the world of industrial processing…
- Has harsh conditions
- Process equipment is picky
- Has strict environmental and safety regulations
These processes require valuable fluids and a large amount of capital investment. As a result, overpressure in a system can cause costly shutdowns and equipment failures. Furthermore, damage can cause harm to the people who run these processes 24/7.
It is crucial to specify, install, and maintain pressure relief valves correctly. Doing things right benefits your business, your process, and your safety.
Many options are available to you, as you learned today. It is important to find a solution that meets all your needs, one that is tailore to your needs. For such an important part of your plant, there is no reason to take shortcuts.
Also, read 10 Most Common Plumbing Problems and How To Fix Them
