Pressure is a force that can be put to good use but can do great harm if left to its own devices. In plumbing there has to be a certain amount of pressure going on, making the water, steam or whatever flow with the required intensity. But allow the pressure to increase past a certain point and trouble is brewing: something has got to give. Good pressure gets water or oil to where it is needed fast enough to fulfil a need. Bad pressure – excess pressure – causes dams to burst, rivers to swarm out over their banks, and plumbing or irrigation systems to malfunction.
Pressure Reducing Valve vs Escape Valve
A pressure reducing valve (PRV) is very different from an escape valve, which, as the name suggests, allows a substance – usually air or steam – to simply get out, reducing the pressure by its absence.
A pressure reducing valve regulates the flow. It maintains a safe and consistent pressure level within the system by adjusting the flow as needed.
Divert or Reduce vs Abort: How Does a Pressure Reducing Valve Work?
The avoidance of internal damage or even bursting is why pressure-relieving measures must be put in place to protect against potential trouble. If you can allow the water in a dam to run away harmlessly once it reaches a critical point, the dam survives. With rivers that is unfortunately not often the case, and the result is flooding, damage, destruction and distress.
If you scale that down to a project you are working on as a plumber, fitter or irrigation engineer, the same principles apply, and although the scale might be smaller, the situation can be equally calamitous. A burst pipe in an industrial setting can bring danger to anyone working in the vicinity. It could be water, steam, oil or effluent. Inside the pipe, at a certain pressure, it’s fine. Allow it to come shooting out at the end or escape in an uncontrolled way and there’s trouble. But even if it stays where it should be, excess pressure can cause malfunctions.
To abort the operation would be one safety measure, but it would waste time. Regulation is the name of the game here: controlling the flow.
How Does a Pressure Reducing Valve Work? The Mechanics
A typical design consists of a spring-loaded diaphragm or piston which reacts in an “intelligent” way. As the downstream pressure rises above the set level, the diaphragm or piston and the spring combine to adjust the barrier, putting it in the way of the flow and reducing it. If the pressure falls below a certain point a pressure valve may be set to do the opposite, getting out of the way and allowing the flow to increase.
This sort of valve may be primitive in its concept and design, but it was designed by humans and, in its own way, it gives mechanisms a form of intelligence.