Miniature Series Port Sizes 1/8" & 1/4"; Flow to 19 scfm (538 l/min)

Product Overview

The ROSS Controls Miniature Filter/Regulator combines air filtration and pressure regulation into a single compact, inline-mounted assembly designed for pneumatic systems where space is at a premium. Supporting port sizes of 1/8" and 1/4" NPT or G (BSPP), the series delivers flow capacity to 19 scfm (538 l/min) with a piston-type regulator that provides precise, stable downstream pressure control.

The inline mounting configuration makes the series well suited for integration directly into pneumatic lines without the need for panel cutouts or manifold blocks. A 5-micron polyethylene filter element removes particulate contamination before air reaches pressure-sensitive downstream components, protecting actuators, cylinders, and precision control valves from wear and malfunction.

Bowl options include a polycarbonate plastic bowl for visual fluid level monitoring and an aluminum bowl for applications requiring higher temperature capability. Both manual drain and automatic drain configurations are available, allowing maintenance teams to select the appropriate condensate removal strategy for their installation. The piston-type regulator design delivers consistent outlet pressure even as inlet pressure varies, reducing process variability in downstream pneumatic circuits.

The Series is part of the ROSS Controls comprehensive air preparation product line, designed to interface modularly with ROSS filters, lubricators, and lockout valves where system requirements expand beyond filtration and regulation alone.

Key Engineering Features

• Inline Mounting Configuration - Mounts directly in the pneumatic supply line without manifold blocks or panel modifications, reducing installation complexity and overall system footprint in space-constrained applications.
• Piston-Type Regulator - Delivers precise, stable outlet pressure control with excellent flow capacity relative to the compact body size, maintaining regulated pressure as flow demand varies across the operating range.
• Polycarbonate or Aluminum Bowl - Polycarbonate bowl provides visual condensate level monitoring; aluminum bowl extends the maximum media temperature rating to 150 degrees F (66 degrees C) for higher-temperature installations.
• Automatic or Manual Drain - Automatic drain removes condensate without operator intervention; manual drain provides positive control of condensate removal for applications with contamination concerns or periodic maintenance schedules.
• 5-Micron Polyethylene Filter Element - Standard 5-micron rated polyethylene element captures solid particulate contamination, protecting downstream pneumatic components from accelerated wear and contamination-related failures.
• NPT and G (BSPP) Thread Options - Available with NPT threads for North American installations or G (BSPP) threads for international applications; G thread models ordered by adding a C prefix to the model number.
• Compact 2-oz (60 ml) Bowl Capacity - The 2-oz bowl volume is matched to the flow and condensate generation rates typical of miniature-series pneumatic circuits, keeping overall unit dimensions minimized.
• Self-Relieving Regulator Function - The piston regulator is self-relieving, allowing downstream pressure to bleed off through the exhaust port when the set point is reduced, eliminating the need for manual downstream venting.
• Outlet Pressure to 100 psig (7 bar) - Adjustable regulated outlet pressure range supports the full operating envelope of most pneumatic actuators and control devices used in miniature-format pneumatic systems.
• Replacement Filter Elements Available - 5-micron polyethylene (standard), 5-micron sintered bronze, 20-micron sintered bronze, and 40-micron sintered bronze replacement elements are available for varying filtration requirements and service conditions.

Technical Specifications

General Specifications

Certifications & Compliance

Typical Applications & Industries

Pneumatic Tool and Equipment Supply

• Point-of-use air preparation for pneumatic screwdrivers, impact wrenches, and small reciprocating tools where a compact inline unit provides both filtration and regulated pressure without requiring a dedicated panel or manifold space.
• Handheld assembly tools on production lines requiring clean, pressure-regulated air at the tool inlet to protect internal mechanisms and ensure consistent torque output across production shifts.
• Small pneumatic grippers and clamps in pick-and-place automation where the miniature form factor allows direct mounting adjacent to the actuator, minimizing unregulated line volume between the FR and the point of use.
• Air-bearing and air-spindle supply circuits where both filtration quality and precise pressure stability are critical to bearing gap maintenance and rotational accuracy.

Electronics and Semiconductor Manufacturing

• Compressed air supply to pneumatic nozzles and dispense heads in electronics assembly, where the 5-micron filtration element removes particulate that could contaminate sensitive circuit board surfaces or adhesive dispensing systems.
• Vacuum generator supply circuits in pick-and-place SMT equipment where clean, regulated air ensures consistent vacuum levels at the venturi and reliable component pickup across thousands of cycles per hour.
• Instrument air supply to precision pressure transducers, valve positioners, and control instruments in process control panels requiring stable inlet pressure and clean air free of condensate and particulate.

Laboratory and Test Equipment

• Pneumatic actuator supply in laboratory test fixtures and automated test equipment (ATE) where compact unit size enables integration within instrument racks and test enclosures with minimal footprint impact.
• Pressure supply regulation for precision flow calibration equipment where the self-relieving piston regulator provides stable reference pressures during calibration sequences.
• Cleanroom equipment where the aluminum bowl option supports the slightly elevated temperature environments sometimes encountered in process chambers, and the sealed construction limits contamination risk.

Packaging and Light Assembly

• Point-of-use air conditioning for small-format blowing, ejecting, and air knife applications on packaging lines where flow capacity to 19 scfm is sufficient and compact mounting is essential.
• Medical device assembly equipment requiring clean filtered air to pneumatic actuators in environments where contamination control and reliable pressure regulation directly affect product quality outcomes.
• Dental and medical instrument supply where the miniature body size and NPT or BSPP thread options allow integration into equipment designed to international standards.

Ordering and Model Number Configuration

The Series model number encodes the regulator type, bowl type, drain type, and port size. Select the appropriate model number from the tables above or configure using the code structure below.

For G (BSPP) threads, add the prefix C to the model number (e.g., C5321C1032 for 1/8 G port with polycarbonate bowl, piston regulator, automatic drain).

Piston-type regulator models are identified by the third digit in the model number: piston = 1, diaphragm = 2.

Polycarbonate bowl models begin with 5321; aluminum (metal) bowl models begin with 5322.

Automatic drain variants end in 32 or 31; manual drain variants end in 02 or 01.

Contact ROSS Controls at (800) 438-7677 for configurations outside the standard model list or for assistance selecting the appropriate replacement filter element.

Accessories

Replacement Filter Elements

Standard 5-micron polyethylene element (933K77) and optional sintered bronze elements in 5-micron, 20-micron, and 40-micron ratings are available. Sintered bronze elements provide greater mechanical durability in high-condensate or heavy-contamination environments.

Modular Add-On Components

The Series can be combined with ROSS modular lubricators and individual filters to build a complete FRL train where system requirements extend beyond integrated filtration and regulation. Contact ROSS Controls for modular compatibility configurations.

Related Products & Accessories

• Mid-Size Series Integrated Filter/Regulator - Modular-mount integrated FR for port sizes 1/4" to 1/2" with flow to 100 scfm, polycarbonate or zinc bowl, piston-type regulator. https://www.rosscontrols.com/en/series/132-mid-size-series
• Full-Size Series Integrated Filter/Regulator - Modular-mount integrated FR for port sizes 1/4" to 3/4" with flow to 138 scfm, piston-type regulator. https://www.rosscontrols.com/en/series/133-full-size-series
• Mid-Size Series Integrated Filter/Regulator - Modular-mount integrated FR with self-relieving piston or non-relieving regulator, tamper-resistant adjusting knob, port sizes 1/4" to 1/2". https://www.rosscontrols.com/en/series/65-mid-size-series
• MD3 Series Integrated Filter/Regulator - Modular integrated FR with diaphragm regulator, L-O-X lockout valve option, port sizes 1/4" to 1/2", flow to 110 scfm. https://www.rosscontrols.com/en/series/66-md3-series
• ROSS FRL Filters - Individual particulate, coalescing, and adsorbing filters for modular or inline mounting across the full port size range. https://www.rosscontrols.com/en/categories/filters
• ROSS Precision Regulators - High-accuracy precision pressure regulators for instrument air and process control applications requiring tighter pressure tolerances. https://www.rosscontrols.com/en/categories/regulators

Frequently Asked Questions (FAQ)

Q: What is the maximum flow capacity of the Miniature Series?

A: The Miniature Series is rated for flow to 19 scfm (538 l/min). This capacity is suitable for point-of-use supply to small actuators, pneumatic tools, and instruments. For higher flow requirements, the Mid-Size Series (to 100 scfm) or Full-Size Series (to 138 scfm) should be considered.

Q: What port sizes are available?

A: The Series is available in 1/8 inch and 1/4 inch port sizes with either NPT or G (BSPP) threads. For G thread models, add the prefix C to the NPT model number.

Q: What is the maximum outlet pressure?

A: The piston-type regulator is adjustable up to 100 psig (7 bar). This covers the operating range of most standard pneumatic cylinders, actuators, and tools used in industrial automation.

Q: What is the maximum inlet operating pressure?

A: With a polycarbonate bowl, maximum operating pressure is 150 psig (10 bar) for both auto drain and manual drain models. With an aluminum (metal) bowl, maximum operating pressure increases to 200 psig (14 bar).

Q: What are the temperature limits?

A: Polycarbonate bowl models are rated for ambient and media temperatures from 40 to 125 degrees F (4 to 52 degrees C). Aluminum bowl models extend the upper temperature limit to 150 degrees F (66 degrees C), making them suitable for slightly elevated temperature environments.

Q: Should I choose the automatic drain or manual drain version?

A: Automatic drain models remove condensate without operator intervention and are recommended for unattended systems, remote installations, or high-humidity environments where condensate accumulation is frequent. Manual drain models give operators direct control over condensate removal and are preferred when condensate composition needs to be monitored or when contamination management protocols require periodic manual inspection.

Q: What is the difference between the polycarbonate and aluminum bowl options?

A: The polycarbonate bowl provides visual inspection of condensate levels and is suitable for clean and moderate environments up to 125 degrees F. The aluminum bowl eliminates the visual inspection capability but raises the maximum temperature rating to 150 degrees F and is more resistant to impact and chemical exposure from certain solvents and coolants.

Q: Is the regulator self-relieving?

A: Yes. The piston-type regulator in the series is self-relieving, which means that when the set pressure is reduced, excess downstream pressure bleeds back through the regulator exhaust rather than requiring manual downstream venting. This simplifies pressure adjustment during commissioning and operation.

Q: What filter element is standard, and what alternatives are available?

A: The standard element is a 5-micron rated polyethylene element (model 933K77). Optional sintered bronze elements are available in 5-micron (R-KA130-27E5), 20-micron (R-KA130-27E4), and 40-micron (R-KA130-27E3) ratings. Sintered bronze elements are more durable in high-condensate environments and can be cleaned and reused.

Q: What is the bowl capacity?

A: The Series uses a 2-oz (60 ml) bowl. This compact capacity is appropriate for the flow rates and condensate generation typical of miniature-series pneumatic circuits and keeps overall unit dimensions minimized.

Q: Can the series be used with a panel mount?

A: Yes. The Series supports panel mounting using a 1-3/16 inch (30 mm) diameter hole. This allows the unit to be mounted through a panel or enclosure wall with the bowl accessible from the front for maintenance.

Q: How does the Miniature Series differ from the Bantam Series?

A: The Bantam Series is a modular-mount unit available with quick-connect tube fittings and threaded port options including metric sizes. The Miniature Series is an inline-mount unit available in NPT and G thread configurations only. Both series share similar flow capacity ratings and specifications, but the series is optimized for direct inline installation while the Bantam is designed for modular system assembly.

Q: Are 3D CAD models available?

A: Yes. ROSS Controls provides downloadable CAD models for the series through the product page at rosscontrols.com. Contact ROSS Controls at (800) 438-7677 or visit the series page for direct download access.

Q: What is the warranty on the series?

A: ROSS Controls provides a one-year warranty on all products, covering defects in material and workmanship from the date of purchase. For warranty claims or technical support, contact ROSS Controls USA at (800) 438-7677.

Installation & Maintenance Guidelines

• Mount inline in the compressed air supply line with the inlet port connected to the upstream supply and the outlet port directed toward downstream pneumatic equipment.
• Install with the bowl oriented downward to allow condensate to collect by gravity for proper automatic or manual drain operation.
• Ensure inlet supply air is free of lubricant mist unless downstream components require lubrication; excessive oil contamination will shorten filter element service life.
• Do not exceed the maximum operating pressure rating for the selected bowl type: 150 psig for polycarbonate bowls, 200 psig for aluminum (metal) bowls.
• Do not expose polycarbonate bowls to solvents, cleaners, or chemicals that attack polycarbonate. Use aluminum bowl models in environments where chemical exposure is possible.
• For manual drain models, drain condensate regularly before the bowl fills to capacity to prevent water carryover into the downstream air circuit.
• Replace the filter element when pressure drop across the unit increases noticeably or on a scheduled maintenance interval based on observed contamination rates.
• Use thread sealant or thread tape on NPT ports; do not use excessive sealant that could enter the air circuit and contaminate downstream components.
• Verify that the regulated outlet pressure is set within the acceptable range of downstream components before energizing the system.
• When using the panel mount feature, install the mounting nut securely with the bowl side accessible for periodic element replacement and condensate draining.

Warranty & Global Support

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

Global technical support is available through ROSS offices in the USA (headquarters in Ferndale, Michigan), Canada, Brazil, Germany, France, United Kingdom, India, China, and Japan.

Contact ROSS Controls USA at (800) 438-7677 or visit rosscontrols.com for product configuration, technical support, and distributor locator services.

For complete technical data, dimensional drawings, and product configurator access, visit the ROSS Controls Miniature Series product page or contact ROSS Controls directly.

Download Catalog: https://www.rosscontrols.com/en/series/131-miniature-series