Pressure Regulators

A Pressure Regulator automatically regulates the flow to maintain pressure in accordance with the amount of demand.

Go to Specific Area of Interest: Pressure Regulator Technical Information | Principal of Operation and Sizing of Pressure Regulators | Pressure Regulator "Droop" | Pilot Operated Regulators | Tank Blanketing Valves | Vacuum Regulators and Breakers |


Pressure Regulator Technical Information

The following information is from GO Regulator:

Regulator Technical Reference - This Technical reference details Mass Spectrometer Helium Leak Certification, Subatomic Units of Measure, Flow Calculations for GO Regulator Products, CGA Connection Chart, Typical Pressure Regulator along with Applications.

Regulator Glossary of Regulator Terms - A useful reference

Instructions for the General Use of Go Products - Some very useful technical instructions.

Go Regulator Pressure Animations - These Animations give a good indication of how regulators work.

GO Regulator Corrosion Chart

Calculators - A series of Cv, Maximum Flow and Backpressure Calculators from Go Regulators:

PSI Conversion Factors

Temperature Conversion Calculator


Principal of Operation and Sizing of Pressure Regulators

Cutting Costs using Self-Operated Regulators - Wolfgang Hesse - At the beginning of the last century, the first self-operated regulators were used for simple control tasks which marked the beginning of process automation. Nowadays, many of us are not aware of the advantages, the design, the principle of operation as well as the limits of this type of technology. In this paper, Samson’s Mr Wolfgang Hesse outlines how cost effective self-operated regulators can be. This is a zipped file thanks Samson Controls.
Introduction to Self-operated Regulators - Self-operated regulators take over all the tasks required in a control loop. They integrate measuring sensor, controller as well as control element all in one system (Fig. 2). The combination of these components results in very rugged and reasonably priced devices - Thanks to Samson Controls.

The following links are from Emerson Process Management:

  • Introduction to Regulators - Instrument engineers agree that the simpler a system is the better it is, as long as it provides adequate control. In general, regulators are simpler devices than control valves. Regulators are self-contained, direct-operated control devices which use energy from the controlled system to operate whereas control valves require external power sources, transmitting instruments, and control instruments. This comprehensive Technical Reference guide includes articles covering regulator theory, sizing, selection, overpressure protection, and other topics relating to regulators. This section begins with the basic theory of a regulator and ends with conversion tables and other informative charts.
  • Glossary - Glossary of regulator terms for reference.
  • Principles of Operations & Regulator Sizing Theory - Regulators provide a means of controlling the flow of a gas or other fluid supply to downstream processes or customers. An ideal regulator would supply downstream demand while keeping downstream pressure constant; however, the mechanics of direct-operated regulator construction are such that there will always be some deviation (droop or offset) in downstream pressure.
  • Valve Sizing (Standardised Method) - Fisher® regulators and valves have traditionally been sized using equations derived by the company. There are now standardized calculations that are becoming accepted world wide. Some product literature continues to demonstrate the traditional method, but the trend is to adopt the standardized method.
  • Complete Technical Section on Pressure Relief Valves - This huge 10 Meg file is a Download of the complete Technical Section tabbed with bookmarks.
  • Temperature Considerations - Freezing has been a problem since the birth of the gas industry. This problem will likely continue, but there are ways to minimize the effects of the phenomenon.
  • Sulphide Stress Cracking - NACE MR0175, “Sulfide Stress Corrosion Cracking Resistant Metallic Materials for Oil Field Equipment” is widely used throughout the world. In late 2003, it became NACE MR0175/ISO 15156, “Petroleum and Natural Gas Industries - Materials for Use in H2S-Containing Environments in Oil and Gas Production”. These standards specify the proper materials, heat treat conditions and strength levels required to provide good service life in sour gas and oil environments.

Reference - This section contains information regarding elastomers, metals, regulator tips, conversions, equivalents, and physical data.

The following papers are from CEESI, whilst they are older they still address the fundamentals:

  • Operation and Maintenance of Regulators - Jim Massey - the operation and maintenance of regulators is extremely important because a gas regulator is the most critcal mechanism for controlling the movement or ther flow of gas.
  • Fundamental Principles of Self Operated Regulators - James Thomson - This paper discusses the basic purpose of regulators, what affects their performance, things to consider when sizing a regulator and capacity calculations for safety devices.
  • Causes and Cures of Regulator Instability - William H. Eamey - This paper addresses the gas pressure reducing regulator installation and the issue of erratic control of the downstream pressure. A gas pressure reducing regulator’s job is to manipulate flow in order to control pressure. When downstream pressure is not properly controlled the terra unstable control is applied.
  • Gas Service Regulators Installation, Selection, And Operation - Robert McCaslin - Of the many varieties of gas pressure regulators the service regulator is one of the most basic and widely used types. They are typically found on residences, small businesses, and apartments. They are often the final stage of pressure reduction before residential meters, and they typically reduce pounds per square inch inlet pressure to inches water column pressure.
  • Fundamental Principles Of Pilot-Operated Regulators - Brent E. Sayer - A regulator is a mechanism for controlling or governing the movement of machines or the flow of liquids and gases, in order to meet a standard.
  • High Pressure Regulators - Brent E. Sayer - A regulator may be described as a "mechanism for controlling or governing the movement of machines or the flow of liquids and gases, in order to meet a standard." The primary function of a gas or liquid regulator is to match the supply of the fluid moving through it to the demand for the fluid downstream. To accomplish this, the regulator continuously measures the downstream pressure and makes adjustments accordingly.
  • Also there are a huge "swag" of Pressure Regulator papers on the excellent CEESI website, just go to their technical page and type in "Pilot Operated Regulator" on their search engine.

Pressure Reducing Regulator Flow Curves - Selecting a regulator for an application first requires review of its performance capabilities and their alignment with the application’s requirements. The best starting point is the regulator’s flow curve provided by the manufacturer, because it illustrates the regulator’s range of capabilities at one glance. The curve represents the range of pressures that a regulator will maintain given certain flow rates in a system. This technical bulletin provides an overview of how to read regulator flow curves for pressure-reducing regulators. It describes some of the complexities, including droop, seatload drop or lockup, choked flow, hysteresis, and supply pressure effect (SPE), also known as dependency - from Swagelok.

Pressure Regulator Selection Strategy - Using Flow Curves for Effective Regulator Specification - Bill Menz - The best way to select a regulator for your application is to examine its flow curve, which is often provided by the manufacturer. "Flow curve" is a misleading name. You could easily call it a "pressure curve" instead, since a regulator controls pressure, not flow. The curve represents the range of pressures that a regulator will maintain given certain flowrates in a system. When selecting a regulator, you are not just looking for the right size - you're looking for a set of capabilities, which is a function of the regulator's design. A flow curve illustrates the regulator's range of capabilities at a glance - from Swagelok.

Pressure Regulators Simplicity May Suffice - Seeking a good, economical alternative to control valves? Pressure regulators may be the right choice - Pressure regulators are very simple control devices, taking necessary operating energy from the process. In contrast, control valves require transmitters, controllers, and external energy sources - From Dave Harrold and Control Engineering.


Pressure Regulator "Droop"

Combating Droop in Self-Contained Pressure Regulators - Tim Gainer - When qualifying valves for any pressure reduction application, there are several factors to consider. Initially, you must decide whether the application requires a control valve in order to be effective, or would a self-contained or piloted regulator be sufficient? from

Dealing with Droop - Maintaining the Set Point in Self-Contained Pressure Regulators - T. Gainer - When qualifying valves for a pressure-reduction application, chemical plant engineers must consider several factors. Initially, they must determine whether or not the application requires a control valve to be effective. Would a self-contained or piloted regulator be sufficient? To make this decision, plant personnel should consider (a) The pressure drop, or the difference between P1 and P2, (b) The set point, (c) The potential for large flow variations and (d) the level of importance of regulation/control. If it meets the design criteria, a regulator will prove a more effective means of pressure reduction in almost all cases. In addition to lower overall costs, a regulator offers other advantages, most important of which is fast response - from Chemical Processing.


Pilot Operated Regulators

Fundamental Principles of Pilot Operated Regulators - Steve Berry - For all practical purposes, regulators, used by the gas distribution industry can be placed in either of two categories: Self-Operated or Pilot-Operated. This paper examines them both. Thanks to Emerson Process Management and


Tank Blanketing Valves

Tank Blanketing Regulators for Effective Gas Blanketing - Over many years, gas blanketing has become a widely accepted practice in many industries. The process of gas blanketing is simply to create and maintain a slightly positive pressure in a storage tank, vessel or container with an inert gas - from SA Instrumentation and Control.

The Complete Blanketing and Safety Valve System - This technical bulletin gives a description of blanketing or padding, Blanketing Valve Operation and Performance Characteristics - from Anderson and Greenwood.

The Tank Blanketing Technique - Tank blanketing, also known to as tank padding, is the procedure of smearing a gas to the empty space in a storage tank or container (the term storage container refers to any container that is used to store products, regardless of its size). This technique is used for a variety of reasons and typically involves using a buffer gas to protect products inside the storage container. Some of the benefits of blanketing include a longer life of the product in the container, reduced hazards, and longer equipment life - from

Tank Blanketing Basics Covered - Tank blanketing, or padding, refers to applying a cover of gas over the surface of a stores commodity; usually a liquid. Its purpose is either to protect or contain the stored product or prevent it from harming personnel, equipment, or the environment. In most cases the blanketing gas is nitrogen, although other gases may be used. Blanketing may prevent liquid from vaporizing into the atmosphere. It can maintain the atmosphere above a flammable or combustible liquid to reduce ignition potential. It can make up the volume caused by cooling of the tank contents, preventing vacuum and the ingress of atmospheric air. Blanketing can simply prevent oxidation or contamination of the product by reducing its exposure to atmospheric air. It can also reduce the moisture content. Gas such as nitrogen is supplied in a very pure and dry state - from


Vacuum Regulators and Breakers

Vacuum Control - Vacuum regulators and vacuum breakers are widely used in process plants. Conventional regulators and relief valves might be suitable for vacuum service if applied correctly - from Emerson Process Management.

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