Techshore Institute Blogs about Best Technical and Management Courses: TECHSHORE INSPECTION SERVICES :PRESSURE REGULATOR

Introduction

A pressure reducing regulator is a device which is used to reduce a high source pressure to a lower working pressure that is suitable for a user’s application. The regulator will have to maintain the outlet pressure within acceptable limits as other conditions may vary. the input pressure and media (gas or liquid) flow are among these varying conditions. A regulator’s efficiency and accuracy in performing its function is determined by the effect of combination of the basic regulator elements designed into a specific regulator unit. The basic elements of a regulator will determine the regulator type and series selected for a particular application. In this manual, it will discuss the three basic elements common to all pressure reducing regulators.

Pressure Reducing Regulator/Valve (PRV)

The function of a pressure reducing regulator is to reduce a high upstream pressure of a gas or liquid (from a compressor, pump, etc) to a lower, stable pressure for the user’s application. The regulator will attempt to control and maintain the outlet pressure within limits as other conditions vary but the pressure regulator will not regulate the control of flow, only the delivery pressure. A regulator should not be used as a shut-off device because there will be always a small amount of leakage across the seat. A shut-off valve must be used downstream of the regulator if any isolation is required.

Back Pressure Regulator/Valve (BPR)

The function of a backpressure regulator is to control and limit the upstream pressure of a gas or liquid (from a tank, pump, etc) and is much more efficient than a relief valve. Most direct spring operated safety relief valves have a high reseating pressure which is unreliable and inconsistent. This is the main difference between a safety relief valve and a backpressure regulator. As such, when it’s set pressure is overcome, it will blow open immediately and exhaust all of the pressure. It needs to be able to handle the flow of the system for sudden exhaust to protect downstream apparatus. A backpressure regulator is never a safety device, it is designed only for precision upstream pressure control.
When the regulator set-point is overcome, it will open (not blow wide open) and try to exhaust just the extra pressure above the set-point. When it cracks open, it uses its sensing element (relief valve’s do not have sensing elements) to situate very close to its original set pressure. Most backpressure regulators have crack-to-reseat pressures less than 2% of the set-point or relief valves will have typically ± 10%. The Three Basic Elements are:

1. The LOADING MECHANISM provides the means by which the operator can set up the force that finds the outlet pressure of the regulator. P2 is a term commonly used to refer outlet pressure.

2. The SENSING ELEMENT senses the changes in the outlet pressure ( P2) through a cavity located under it, allowing the regulator to respond accordingly to these changes in P2. The sensing element also provides a physical link between the the control element and loading element.

3. The CONTROL ELEMENT reduces the inlet pressure, commonly called P1, to a lower working pressure and maintains by increasing or decreasing the orifice

Applications Air compressorsAircraftAerospaceWater pressure reductionOxy-fuel welding and cuttingGas powered vehiclesRecreational vehiclesBreathable air supplyMining IndustryOil and gas industry

Techshore Institute Blogs about Best Technical and Management Courses

Tuesday, February 28, 2017

TECHSHORE INSPECTION SERVICES :PRESSURE REGULATOR

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