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Gas Cylinder Pressure Regulators: High Precision for All Applications

A cylinder pressure regulator is an essential device when using compressed gas. Pressure regulators reduce pressure and control gas flow for safe use. Whatever gas you use, whether oxygen, nitrogen, propane, Carbone dioxide (CO2) or specialty gases, the choice of cylinder pressure regulator is crucial for safety, efficiency and compliance.

Pressure Regulators Technology Overview

Rotarex uses 4 main technologies to achieve stable and reliable pressure reducing performance.

Diaphragm Pressure Regulator:

  • Most widely used technology (cylinder control, in-line control, expansion module...)
  • Compact design
  • High precision


Bellows Pressure Regulator:

  • High outlet pressure accuracy
  • Less sensitive to outlet pressure rise
  • Mainly used for applications such as chromatography


Piston Pressure Regulator:

  • Constant outlet pressure
  • Used for regulators with outlet pressure close to inlet pressure/s
  • Used as the 1st stage of a dual-stage regulator
  • Used for calibration regulators and analytical instruments

Balanced-Valve Pressure Regulator:

  • Ensures excellent outlet pressure stability
  • Minimizes the effect of inlet pressure fluctuations on outlet pressure
  • Extends valve life and reduces operating costs by reducing stress on the seat
  • Diaphragm technology only

Pressure Regulators

Specialty Gas Pressure regulators

  • Diaphragm single stage high pressure regulator with cartridge - SC280/SC380
    SC280 - SC380
    High pressure regulator
    Single stage
    Diaphragm tech. + Cartridge
  • Diaphragm single stage high pressure regulator - S220
    S220
    High pressure regulator
    Single stage
    Diaphragm technology
  • Piston single stage high pressure regulator - S400
    S400
    High pressure regulator
    Single stage
    Piston technology
  • Diaphragm single stage high pressure regulator with balanced valve - S800
    S800
    High pressure regulator
    Single stage
    Diaphragm technology + BV
  • Single stage low pressure regulator - Specyl Serie
    Specyl 25
    Low pressure regulator
    Single stage
    25 bar Inlet pressure
  • Diaphragm single stage high pressure regulator for very high flow - TDG250
    TGD250
    Very high flow pressure regulator
    Single stage
    Diaphragm technology
  • Diaphragm dual stage high pressure regulator with cartridge - DC280/DC380
    DC280 - DC380
    High pressure regulator
    Dual stage
    Diaphragm tech. + Cartridge
  • Piston/Bellow dual stage high pressure regulator - D230
    D230
    High pressure regulator
    Dual stage
    Piston/Bellow technology
  • Piston/Diaphragm dual stage high pressure regulator - D230-0.1
    D230-0.1
    High pressure regulator
    Dual stage
    Piston/Diaphragm technology
  • Diaphragm low pressure regulator with balanced valve - S10
    S10
    Low pressure regulator
    Single stage
    Diaphragm technology + BV
  • Diaphragm low pressure regulator with balanced valve for high flow - S15
    S15
    High flow low pressure regulator
    Single stage
    Diaphragm technology + BV
  • Diaphragm Single Stage High Pressure Regulator with Cartridge for Food Industry – SC290
    SC290 F
    High pressure regulator
    Single stage
    Diaphragm tech. + Cartridge
  • Bellow low pressure regulator - S20
    S20
    Low pressure regulator
    Single stage
    Bellow technology
  • Diaphragm low pressure regulator for very low outlet pressure - S20-0.1
    S20-0.1
    Low pressure regulator
    Single stage
    Diaphragm technology
  • Diaphragm low pressure regulator - S55
    S55
    Low pressure regulator
    Single stage
    Diaphragm technology
  • Diaphragm low pressure regulator with balanced valve for very high flow - DC50
    DC50
    Low pressure regulator
    Single stage
    Diaphragm technology + BV

Specialty Gas Point of use

  • Bellow point of use - S21
    S21
    Point of use
    Bellow technology
  • Bellow modular point of use - Labline S22
    Labline S22
    Point of use
    Modular
    Bellow technology
  • Diaphragm integrated point of use with balanced valve - MS15
    MS15
    Point of use
    Integrated
    Diaphragm technology
  • Bellow integrated point of use - MS20
    MS20
    Point of use
    Integrated
    Bellow technology

Flow regulators

  • Piston constant flow regulator equipped with 10 positions flow selector - S75
    S75
    Constant flow regulator
    10 positions flow selector
    Piston technology

Ultra high purity pressure regulators

  • Compact single-stage diaphragm pressure regulator for HP & UHP gases - RX1000
    RX1000
    HP & UHP regulator
    Cv 0.09, 0.15
    Free diaphragm
  • Single-stage diaphragm pressure regulator for HP & UHP gases - RX3000
    RX3000
    Single stage diaphragm
    Cv 0.09, 0.15
    Inlet 21/240 bar
  • Sub-atmospheric pressure regulator for HP & UHP gases - RX3100
    RX3100
    Sub-atmospheric
    Cv 0.09
    Inlet 21 bar
  • Single-stage tied-diaphragm pressure regulator for HP & UHP gases - RX3200
    RX3200
    Single stage tied-diaphragm
    Cv 0.09, 0.15
    Inlet 21/240 bar
  • Diaphragm loaded high pressure regulator for HP & UHP gases - RX3600
    RX3600
    High pressure diaphragm
    Cv 0.15
    Inlet 240/310 bar
  • Piston loaded high pressure regulator for HP & UHP gases - RX3700
    RX3700
    High pressure piston
    Cv 0.09, 0.15
    Inlet 310 bar
  • Dual stage pressure regulator for HP & UHP gases - RX3900
    RX3900
    Dual stage regulator
    Cv 0.09
    Inlet 240/310 bar
  • Single-stage diaphragm pressure regulator for HP & UHP gases - RX4000
    RX4000
    Single stage diaphragm
    Cv 0.15, 0.25, 0.5, 0.9, 1.1
    Inlet 21/117/207/240 bar
  • Sub-atmospheric pressure regulator for HP & UHP gases - RX4100
    RX4100
    Sub-atmospheric regulator
    Cv 0.5
    Inlet 21 bar
  • Single-stage tied-diaphragm pressure regulator for HP & UHP gases - RX4200
    RX4200
    Single stage tied-diaphragm
    Cv 0.15, 0.25, 0.5, 0.9, 1.1
    Inlet 21/117/207/240 bar

How Does a Gas Cylinder Pressure Regulator Work?

  • Gallery item
    Gas pressure inside a cylinder is caused by the gas molecules moving around and colliding into the walls of the cylinder. The more molecules there are in the cylinder, and the faster they move, the higher the pressure becomes. So, if a cylinder is very full or contains a gas stored under high maximum pressure, the molecules are tightly packed and moving rapidly, which results in high internal pressure.
  • Gallery item
    The actual pressure in a gas cylinder depends on several factors: the type of gas, the size and the diameter of the cylinder, and how full it is. On the market, gas cylinders are available with pressures ranging from relatively low levels (for example, around 5–30 bar) up to very high pressures, such as 200 or even 300 bar, especially for industrial, instrument or medical use. Temperature also plays a role: as it rises, internal pressure increases.
  • Gallery item
    However, this high pressure is not suitable for direct use. To safely distribute the gas through piping systems or deliver it to equipment or appliances, the pressure must first be reduced. That’s why a pressure regulator (also called a pressure reducer) is connected to the cylinder valve. This device includes a chamber where the gas can expand and slow down, reducing the pressure to a safe and steady level for practical use.
  • Gallery item
    Inside the regulator, gas first enters a small chamber where it can expand. A spring-loaded valve automatically adjusts to control pressure and how much gas passes through. When the pressure is too high, the valve tightens; when the pressure drops, it opens more. In this way, the regulator maintains a constant, safe gas flow regardless of how full the cylinder is or how temperature fluctuates.

What to Consider When Specifying a Regulator?

Regulator Body Materials

Most Rotarex regulators are available in 316L stainless steel or chrome-plated brass, while some models are available in raw brass or aluminum. Regulator materials are specified in accordance with the chemical and physical properties of the gas.


  • 316L stainless steel: The recommended option for corrosive gases and high or ultra-high purity applications, due to its superior strength, non-reactivity, exceptional durability and excellent surface finish. It is compatible with virtually all gas types. Rotarex uses type 316L stainless steel, an autentic nickel-chromium stainless steel containing molybdenum. It guarantees:
    • Outstanding corrosion resistance - particularly against sulphuric, hydrochloric, acetic, formic and tartaric acids, acid sulphates and alkaline chlorine;
    • Resistance to stinging by chloride ion solutions; and
    • Outstanding resistance even at high temperatures

  • Chrome-plated or raw brass: The most commonly used material for industrial and oxygen applications due to its excellent cost-effectiveness, high strength and low coefficient of friction compared with stainless steel.

What to Consider When Specifying a Regulator?

Inlet / outlet pressure:

Several models are designed to accommodate different inlet and outlet pressure ranges. Standard options cover inlet pressures from 1.5 to 300 bar and outlet pressures from 0.1 to 200 bar. These options are clearly indicated on each product page, but we can also meet special requirements on request. Always verify both inlet and outlet pressure ratings, and when flexibility is required, choose an adjustable regulator that lets you fine-tune the outlet to your desired set point.

The Role of Pressure Relief Valves

A relief valve is an essential component of a pressure regulator. This safety device helps prevent overpressure by releasing excess pressure from the system once it exceeds a predefined maximum pressure. Each Rotarex regulator includes a relief valve, depending on its intended application.

Cylinder valve connections

Specific cylinder valve connectors are required for each type of gas. Default fittings are NPT 1/4" male and 16 x 1.336 male, representing the most common types. Other standards and dimensions are available on request to match your desired setup.

How to choose the right pressure regulator for your application

All applications have precise requirements depending on the end use. That's why Rotarex offers a wide range to meet all your needs. Understanding the differences between types is essential for choosing the right regulator based on pressure range, gas type, usage environment, and precision requirements.

Single-Stage vs Dual-Stage Regulators

A single-stage pressure regulator reduces pressure from inlet pressure to outletonce. They are ideal for applications where inlet pressure remains fairly stable or where precision is less critical. The variation of pressure is due to the decreasing inlet pressure, which naturally drops as the cylinder empties. In most applications, the pressure will still be reduced at the end of the gas line, thanks to point-of-use regulators.
A dual-stage regulator consists of two single-stage regulatorsin a single body, the pressure is indeed reduced twice. This dual configuration provides better pressure and flow stability than single-stage regulators. This improved stability results from the lower pressure variation at the inlet of the second stage of pressure regulation. These are preferred in laboratory, analytical, or high-precision industrial environments

High-pressure vs low pressure regulators

  • High Pressure regulators are designed to handle inlet pressures typically up to 200-300 bar (3000-4500 psi), such as those found in standard industrial gas cylinders. In many systems, they also serve as an intermediate stage between the high-pressure cylinder and a downstream low-pressure regulator, delivering an intermediate pressure that ensures safer operation and more precise control.
  • Low-pressure regulators are intended for situations where the inlet pressure is already reduced (below 50 bar) or where a very low outlet pressure is desired, often in the millibar range. These regulators are not designed to withstand extreme inlet pressures, but they excel at fine-tuning outlet pressure and guaranteeing precise flow, especially at very low flow rates.

General purpose vs Lecture bottle

  • Regulators used for broader applications need to be robust, durable and made of high-quality materials. They are typically used with standard gas cylinders for general-purpose applications in laboratories, industry, medical etc.
  • Lecture bottles are small compact cylinders used in laboratories or for calibration purposes, designed to store high-purity or specialty gases in small quantities. These cylinders require compact pressure regulators to deliver the most precise and stable gas flow possible.

Cylinder pressure regulators vs panel-mounted

  • Cylinder-mounted regulators are the most common setup. This is the configuration offers flexibility to the user regarding where the gas is to be used. In this configuration, the cylinder pressure regulator is connected to the cylinder valve via a cylinder connector
  • Panel-mounted regulators are attached to a control panel or gas distribution board, and are often connected to cylinders via high-pressure flexible hoses or pigtails. Rotarex provides a full range ofsupplyandchangeover boards.

Need Help? Our Gas Supply Experts Can Help You Select the Right Equipment

Choosing the right gas pressure regulator or supply system can be complex, especially with so many variables like gas type, pressure range, flow rate, and application-specific requirements. That's why our team of gas supply specialists is here to support you every step of the way.
Whether you're working in a laboratory, industrial plant, or medical setting, we can help you:
  • Select the right regulator for your cylinder or system
  • Ensure material compatibility and compliance
  • Optimize safety and performance for your application
Frequently Asked Questions About Gas Regulators
What is a gas pressure regulator?

A cylinder pressure regulator is an essential device when using gases. A pressure reducer is a device connected to a valve for the purpose of reducing the pressure contained in the cylinder to a lower suitable pressure for use. It controls pressure by safely lowering cylinder pressure to a usable outlet level. Whatever gas you use, whether oxygen, nitrogen, propane, CO2 or specialty gases, the choice of cylinder pressure regulator is crucial for safety, efficiency and compliance.

WWhat does a pressure regulator do?
The purpose of a regulator is to reduce high pressure from the cylinder and to maintain outlet pressure at the desired level, ensuring it is suitable for use with your application.
Which gases can a regulator be used with?

There are specific regulators for each type of gas. Discover our ranges:

  • Specialty gas pressure regulators
  • Ultra-High-Purity pressure regulators
  • Medical pressure regulators
  • LPG Pressure regulators
Which gas regulator should I choose?

The right gas regulator depends on several key factors related to your specific application. Here are the main criteria to consider (type of gas, inlet pressure, desired outlet pressure, flow rate, applications). It is not always easy to choose the right regulator. Our team of experts is here to help and guide you in your choice. Please do not hesitate to contact us!

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