High Pressure Series Port Sizes 1/8" to 3/8"; Flow to 70 scfm (1982 l/min)

Product Overview

The ROSS Controls High-Pressure Series is a family of inline piston pressure regulators covering port sizes from 1/8" to 3/8" with a maximum inlet pressure of 400 psig (28 bar) and an outlet adjustable up to 390 psig (27 bar). This series addresses applications requiring pressure regulation beyond the 300 psig inlet limit of standard ROSS FRL regulators, including high-pressure pneumatic systems, nitrogen circuits, and compressed gas applications.

Piston construction is used throughout the series, providing robust regulation capability at high inlet pressures. Both self-relieving and non-relieving configurations are available. Self-relieving models automatically exhaust excess downstream pressure when the set point is reduced. Non-relieving models are appropriate when any downstream pressure bleed is undesirable, such as in closed-loop nitrogen circuits or applications where the downstream volume is large and relief would waste significant gas.

The Series uses fluoroelastomer seals, distinguishing it from standard ROSS FRL regulators which use nitrile seals. Fluoroelastomer provides superior compatibility with a wider range of compressed gases and better performance at elevated pressures and temperatures compared to nitrile. The construction material set includes an aluminum body, aluminum dome, nylon knob, brass valve, and nylon valve cap.

The Series is rated for ambient temperatures from 40 to 175 degrees F (4 to 79 degrees C) with a maximum flow of 70 scfm (1982 l/min) at 400 psig (28 bar) inlet. An integrated pressure gauge rated 0 to 600 psig (0 to 40 bar) provides continuous outlet pressure monitoring at the elevated pressures this series is designed to handle.

Key Engineering Features

• Maximum Inlet Pressure 400 psig (28 bar) - Rated 33% higher than standard ROSS FRL regulators (300 psig limit), enabling use in high-pressure pneumatic and compressed gas systems that exceed standard compressed air pressure ranges.
• Outlet Adjustable to 390 psig (27 bar) - Near-full inlet pressure can be achieved at the outlet, enabling high-ratio pressure regulation or near-pass-through configurations for pressure staging applications.
• Self-Relieving and Non-Relieving Options - Self-relieving for applications where downstream pressure bleed is acceptable; non-relieving for closed-loop gas circuits where any pressure loss represents significant cost or safety concern.
• Fluoroelastomer Seals - Superior chemical compatibility and high-pressure performance compared to nitrile seals, extending applicability to nitrogen, inert gas, and other compressed gas media beyond standard compressed air.
• High-Pressure Gauge 0 to 600 psig (0 to 40 bar) - Integrated gauge range calibrated for the high pressure service of the series, providing accurate outlet pressure reading across the full operating range.
• Aluminum Body and Dome - All-aluminum structural construction (body and dome) provides the structural integrity required for high-pressure service at reduced weight compared to steel alternatives.
• Piston Construction - Robust piston design maintains regulation performance at high differential pressures between inlet and outlet, with stable regulated pressure across the flow range.
• Wide Ambient Temperature Range - Rated for 40 to 175 degrees F (4 to 79 degrees C), compatible with a wide range of industrial environments including those near heat-generating compressed gas equipment.
• NPT and G Thread Options - Available in NPTF and G (BSPP) thread forms for all port sizes, enabling use in both North American and international high-pressure pneumatic systems.

Technical Specifications

General Specifications

Certifications & Compliance

Typical Applications & Industries

High-Pressure Pneumatic Systems

• High-pressure compressed air circuits operating above the 300 psig inlet limit of standard FRL regulators, where regulated downstream pressure must be set below the supply level.
• Pneumatic clamp and press circuits using amplified or boosted air supply where supply pressure exceeds 300 psig and downstream regulation is required.
• High-pressure actuator supply systems in industrial automation where boosted pneumatic power is used to achieve higher cylinder force without increasing cylinder bore diameter.
• Pressure staging circuits where a high-pressure supply must be regulated to multiple downstream pressure levels, with the series providing the first-stage regulation.

Compressed Gas Applications

• Nitrogen circuit pressure regulation where the fluoroelastomer seals provide compatibility with nitrogen gas and the 400 psig inlet rating handles typical nitrogen cylinder supply pressures.
• Carbon dioxide and inert gas pressure regulation for industrial purging, blanketing, and process gas supply where standard nitrile-sealed regulators lack chemical compatibility.
• Compressed gas cylinder supply reduction where gas cylinder pressures up to 400 psig must be reduced to process or instrument pressure levels.
• High-pressure gas testing circuits for component pressure and leak testing at above-atmospheric but below 400 psig test pressures.

Specialty Manufacturing

• Plastics blow molding high-pressure circuits where final blow pressures above standard compressed air levels require the series pressure and flow capability.
• Industrial tire and rubber component manufacturing where high-pressure air circuits above 300 psig are used in curing and forming processes.
• Aerospace and defense ground support equipment where high-pressure pneumatic circuits supply test stands, actuator testing, or structural test fixtures.
• Subsea and diving equipment manufacturing test stands where regulated high-pressure air is required for equipment validation before deployment.

Research and Laboratory

• Laboratory test apparatus requiring regulated compressed gas at pressures above standard shop air ranges, using the non-relieving option to conserve expensive gas supply.
• Pressure cycling test equipment where the series non-relieving option prevents downstream pressure loss between test cycles.
• Gas chromatography and analytical instrument supply where clean, regulated compressed gas at precise pressures is required for carrier gas and detector supply.
• University and industrial research pneumatic test rigs requiring regulated supply air at pressures from 15 to 390 psig for component characterization and validation.

Ordering and Model Number Configuration

Related Products & Accessories

• 118 High-Capacity Series Pressure Regulators - Inline piston regulators for high-flow applications at port sizes 3/4" to 1-1/2", 300 psig inlet, flow to 800 scfm. https://www.rosscontrols.com/en/series/118-high-capacity-series
• 113 Miniature Series Pressure Regulators - Inline piston or diaphragm regulators at port sizes 1/8" and 1/4", flow to 40 scfm, for standard pressure applications. https://www.rosscontrols.com/en/series/113-miniature-series
• ROSS Precision Regulators - Miniature precision regulators for applications requiring tight pressure regulation at low flow rates. https://www.rosscontrols.com/en/categories/36-air-preparation-frls
• ROSS FRL Filters - Particulate and coalescing filters for upstream gas preparation at appropriate pressure ratings for high-pressure service. https://www.rosscontrols.com/en/categories/36-air-preparation-frls

Frequently Asked Questions (FAQ)

Q: What port sizes are available for the High-Pressure Series?

A: The High-Pressure Series is available in 1/8", 1/4", and 3/8" port sizes in both NPTF and G (BSPP) thread forms.

Q: What is the maximum inlet pressure?

A: The maximum inlet pressure is 400 psig (28 bar), making the series the highest inlet pressure regulator in the standard ROSS FRL line and the appropriate choice when supply pressure exceeds the 300 psig limit of other ROSS FRL regulators.

Q: What outlet pressures can the series regulate to?

A: Outlet pressure is adjustable up to 390 psig (27 bar) using a 0 to 400 psig (0 to 27.6 bar) main spring, enabling near-full-pressure pass-through or high-ratio downstream regulation across the full 400 psig inlet range.

Q: What is the maximum flow capacity?

A: The High-Pressure Series has a maximum flow of 70 scfm (33.0 l/s) at 400 psig (28 bar) inlet pressure. Flow capacity in standard scfm terms will vary with inlet and outlet pressure conditions.

Q: What is the difference between self-relieving and non-relieving configurations?

A: Self-relieving models automatically exhaust downstream pressure through the regulator when the set point is reduced. Non-relieving models trap downstream pressure when the set point is reduced, requiring a separate exhaust path. Non-relieving is preferred for compressed gas circuits where any downstream pressure bleed wastes expensive or scarce gas supply.

Q: Why does the series use fluoroelastomer seals instead of nitrile?

A: Fluoroelastomer provides broader chemical compatibility than nitrile, covering nitrogen, inert gases, and some other compressed gases in addition to compressed air. It also maintains sealing integrity at higher pressures and temperatures compared to standard nitrile seals.

Q: What pressure gauge is included?

A: The Series includes a pressure gauge rated 0 to 600 psig (0 to 40 bar), calibrated for the high-pressure operating range of this series. Standard FRL gauges rated to 160 or 200 psig are not appropriate for Series applications.

Q: What body material is used?

A: Both the body and dome are aluminum. The knob is nylon. Seals are fluoroelastomer. The valve is brass. The valve cap is nylon. The all-aluminum structural construction provides the strength needed for 400 psig service.

Q: Can the series be used with gases other than compressed air?

A: The fluoroelastomer seals provide compatibility with nitrogen and many inert gases. For specific gas compatibility verification, consult ROSS Controls with the gas composition and operating conditions before specifying the series.

Q: Are G (BSPP) thread models available?

A: Yes. G thread models are available for all port sizes by prefixing the standard model number with 'C' (e.g., C5215B2004 for a 1/4" G self-relieving regulator).

Q: What is the ambient temperature range?

A: The High-Pressure Series is rated for 40 to 175 degrees F (4 to 79 degrees C), the same upper limit as the MD3, Full-Size, MD4, and High-Capacity Series.

Q: Does the non-relieving Series require a separate downstream relief valve?

A: Yes. When using a non-relieving configuration, install an appropriate downstream pressure relief valve to protect equipment against over-pressure in the event of regulator failure or set point error. The non-relieving regulator itself will not exhaust downstream pressure under any condition.

Installation & Maintenance Guidelines

• Install the High-Pressure Series inline with the inlet port connected to the high-pressure supply side and the outlet port connected to the downstream circuit. Do not exceed 400 psig (28 bar) inlet pressure.
• Apply thread sealant to male pipe thread connections only. Keep sealant away from the first two threads to prevent contamination of internal passages. Use thread sealant rated for the maximum system pressure and compatible with the flow medium.
• For non-relieving installations, install a downstream relief valve rated for the maximum safe downstream pressure before placing the circuit in service. The non-relieving regulator will not provide any downstream pressure protection.
• Set the outlet pressure by rotating the adjustment knob clockwise to increase and counterclockwise to decrease. Monitor the integrated 0 to 600 psig gauge during adjustment to confirm the set point is reached correctly.
• Verify self-relieving operation (self-relieving models) by reducing the set point and confirming downstream pressure decreases without a separate exhaust path.
• Support the series body independently of the connected piping at all port sizes to prevent pipe connection stress during system vibration or thermal cycling.
• After initial pressurization, inspect all connections for leaks using an appropriate leak detection solution rated for the system pressure. Do not use soap solutions on high-pressure gas systems without verifying compatibility.
• Do not exceed 390 psig (27 bar) outlet pressure. Although the body is rated to 400 psig inlet, the maximum outlet pressure is 390 psig.
• Mount the regulator with the adjustment knob and gauge accessible from the normal maintenance position. High-pressure systems require particular attention to safe access during adjustment.
• Ensure upstream gas filtration is installed to protect the fluoroelastomer seals and brass valve seat from particulate contamination. Use a filter rated for the system pressure.
• In applications approaching the maximum ambient temperature of 175 degrees F (79 degrees C), confirm that the gauge and seals remain within their rated temperature limits.
• For high-pressure gas (non-air) applications, verify fluoroelastomer seal compatibility with the specific gas before placing the regulator in service. Consult ROSS Controls if compatibility is uncertain.

Warranty & Global Support

ROSS Controls provides a one-year warranty on all products, covering defects in material and workmanship from date of purchase.

Technical support is available through ROSS Controls USA at (800) 438-7677 or by visiting rosscontrols.com.

For product configuration, dimensional drawings, and catalog downloads, visit the ROSS Controls High-Pressure Series product page at rosscontrols.com or contact ROSS Controls directly.

Download Catalog: https://www.rosscontrols.com/en/series/119-high-pressure-series