Mid-Size Series Port Sizes 1/4 to 1/2; Flow to 100 scfm (2832 l/min)

Product Overview

The ROSS Controls Mid-Size Coalescing Filter addresses the air preparation requirements of mid-range pneumatic systems with port sizes from 1/4 to 1/2 and maximum flow to 100 scfm (2832 l/min). Equipped with a borosilicate glass-fiber coalescing element rated at 0.3 micron as standard, with an optional 0.01-micron element, the series removes liquid water, aerosol oil, and sub-micron particulate contamination from compressed air before it reaches pneumatic valves, cylinders, instruments, and process equipment.

A key capability of the Mid-Size Series is its integral differential pressure gauge, which provides a direct indication of element loading and signals when the element has reached the end of its service life. This eliminates guesswork from maintenance scheduling and prevents the premature element replacement that occurs with time-based intervals alone, reducing operating costs in systems with variable contamination loads.

The Series supports both modular and inline mounting configurations. In modular installations, the filter connects directly to ROSS Mid-Size Series regulators and lubricators via porting blocks and coupling kits, creating a compact FRL assembly without intermediate pipe fittings. Inline installation connects the filter directly in the compressed air line using threaded NPT or BSPP ports.

The aluminum bowl with clear nylon sight glass provides both high-pressure capability and visual condensate-level monitoring. An extended aluminum bowl option doubles the liquid storage capacity for high-condensate-generating systems or to extend drain intervals. The zinc body and aluminum bowl construction withstand operating temperatures to 175 degrees F (degrees C), covering the majority of industrial compressed air applications.

Key Engineering Features

• Differential Pressure Gauge - Integral differential pressure gauge on all Series models provides direct indication of element loading, enabling condition-based maintenance scheduling and eliminating unnecessary early element replacement.
• 0.3-Micron and 0.01-Micron Element Options - Standard 0.3-micron borosilicate glass-fiber element removes bulk aerosols for general industrial service. Optional 0.01-micron element upgrades the unit to near oil-free performance for sensitive instrumentation and food-grade applications.
• Modular or Inline Mounting - Compatible with both modular FRL assembly using ROSS porting blocks and coupling kits, and standard inline pipe-threaded installation, providing flexibility to match the installation architecture of the system.
• Aluminum Bowl with Clear Nylon Sight Glass - Standard aluminum bowl with integral sight glass allows visual inspection of the condensate level without removing the bowl, supporting safe and quick maintenance checks during operation.
• Extended Aluminum Bowl Option - Optional extended bowl increases liquid storage capacity from 6 oz (180 ml) to 10 oz (300 ml), extending drain intervals in high-humidity systems and reducing maintenance frequency.
• Zinc Body Construction - Die-cast zinc body provides structural rigidity and corrosion resistance suitable for industrial environments, supporting reliable threaded port connections at operating pressures to 150 psig (10 bar).
• Automatic or Manual Drain - Internal automatic drain removes collected liquid continuously; manual drain provides operator-controlled purging for applications where condensate volume or drain timing must be managed precisely.
• Operating Temperature to 175 Degrees F - Metal bowl construction rated to 175 degrees F (degrees C) ambient and media temperature covers nearly all standard industrial compressed air system environments without requiring special high-temperature options.
• Nitrile Seals - Nitrile elastomer seals maintain reliable compression air sealing and resist degradation from petroleum-based compressor oils across the rated temperature range.

Technical Specifications

General Specifications

Certifications & Compliance

Typical Applications & Industries

Pneumatic Cylinder and Actuator Systems

• Air preparation for pneumatic cylinder banks in manufacturing automation where compressor oil carryover accelerates seal degradation in cylinders and causes valve stiction, increasing maintenance costs and unplanned downtime.
• Actuator supply filtering in paint shops, clean rooms, and precision assembly cells where oil mist in the air supply would contaminate product surfaces or sensitive components being assembled.
• Double-acting cylinder and gripper systems in pick-and-place automation where consistently clean, dry air ensures repeatable stroke force and eliminates stick-slip behavior caused by oil buildup on cylinder walls.

Compressed Air Distribution Systems

• Point-of-use coalescing filtration at individual machine drops in large manufacturing plants where the main compressed air supply contains residual oil from reciprocating or screw compressors that cannot be fully removed at the compressor station.
• Air preparation in pneumatic panel assemblies serving multiple valve islands and motion control components, where the mid-size flow capacity accommodates the aggregate demand of 10 to 30 actuators served by a single drop.
• Retrofit coalescing filtration on existing systems where downstream component failures caused by oil contamination have been identified, and the 1/4 to 1/2 port size covers the majority of industrial machine air supply line sizes.

Process and Industrial Equipment

• Air preparation for pneumatically operated process control valves and butterfly valve actuators in chemical, pharmaceutical, and petrochemical plants where clean, dry air is specified for actuator reliability and regulatory compliance.
• Compressed air supply to pneumatic conveying nozzles and blow-off stations in packaging and material handling where oil contamination would transfer to product surfaces.
• Air preparation for spray systems, air-assisted atomizers, and air knife drying systems where oil in the air supply would cause unacceptable surface contamination on coated or dried products.

Food, Beverage, and Pharmaceutical

• Direct and indirect food contact zone air preparation in filling, sealing, and packaging machines where air purity requirements are mandated by food safety regulations and HACCP plans.
• Pharmaceutical manufacturing equipment air supplies where ISO 8573-1 oil classification requirements must be documented and maintained as part of validation records.

Ordering and Model Number Configuration

Standard bowl is aluminum with clear nylon sight glass. Extended bowl models add '-E' suffix designation in the model number.

The internal float drain option is available; consult ROSS Controls for model numbers.

For BSPP (G) thread ports, consult ROSS Controls for model number prefix conventions.

Accessories including coupling kits, mounting brackets, differential pressure gauges, and accessory kits are ordered separately.

Related Products & Accessories

• 79 Miniature Series Coalescing Filter - Smaller inline coalescing filter for 1/8 and 1/4 port sizes with flow to 10 scfm. https://www.rosscontrols.com/en/series/79-miniature-series
• MD3 Series Coalescing Filter - Higher-flow coalescing filter for 1/4 to 1/2 port sizes with flow to 125 scfm, polycarbonate or metal bowl, and modular/inline mounting. https://www.rosscontrols.com/en/series/81-md3-series
• Mid-Size Series Standard Filters - 5-micron and 40-micron general purpose filters in the Mid-Size form factor for upstream pre-filtration. https://www.rosscontrols.com/en/categories/40-filters
• Mid-Size Series Regulators - Precision pressure regulators for 1/4 to 1/2 port pneumatic systems in the Mid-Size modular assembly format. https://www.rosscontrols.com/en/categories/42-regulators
• Mid-Size Series FRL Combination Units - Factory-assembled filter, regulator, and lubricator combinations with mid-size flow capacity for complete machine air preparation. https://www.rosscontrols.com/en/categories/44-filter-regulator-and-lubricator

Frequently Asked Questions (FAQ)

Q: What is the significance of the differential pressure gauge on the series?

A: The differential pressure gauge measures the pressure drop across the coalescing element. A new, clean element produces a low differential pressure. As the element loads with contamination, the differential pressure rises. When the differential pressure reaches approximately 10 psid, the element should be replaced. This condition-based indicator prevents both premature replacement of a serviceable element and delayed replacement of a loaded element that is restricting flow and increasing system energy costs.

Q: What is the maximum flow capacity of the Mid-Size Series?

A: Maximum flow is 100 scfm (2832 l/min) at 100 psig (6.9 bar) inlet pressure. The flow capacity is the same for all port sizes (1/4, 3/8, and 1/2); the port size selection should match the pipe size in the compressed air system to minimize pressure drop in the connecting fittings.

Q: What is the advantage of the extended bowl?

A: The extended aluminum bowl increases liquid storage capacity from 6 oz (180 ml) to 10 oz (300 ml). This is beneficial in high-humidity environments or with wet-run compressors where condensate accumulates rapidly. The extended bowl reduces the frequency of manual drain operation and lowers the risk of bowl overflow causing liquid carryover past the element in systems without automatic drains.

Q: Can I install the series in a modular FRL assembly?

A: Yes. The Series is designed for modular assembly with ROSS Mid-Size Series regulators and lubricators using compatible porting blocks and coupling kits. This creates an integrated FRL station without intermediate pipe fittings, reducing installation time and potential leak points.

Q: What is the temperature rating of the series?

A: The Series Mid-Size coalescing filter, with the aluminum bowl, is rated for ambient and media temperatures of 40 to 175 degrees F (4 to degrees C). This covers the operating envelope of most industrial compressed air systems in standard production environments.

Q: Which replacement element do I need for the extended bowl?

A: For the extended bowl, order element R-A60F-32 for 0.3-micron rating or R-A60F-32E8 for 0.01-micron rating. For the standard bowl, order R-A60F-29 (0.3 micron) or R-A60F-29E8 (0.01 micron). Standard and extended bowl elements are different lengths and are not interchangeable.

Q: What is the maximum operating pressure?

A: Maximum operating pressure is 150 psig (10 bar) for both automatic and manual drain configurations. The Series aluminum bowl maintains this pressure rating across the full operating temperature range of 40 to 175 degrees F.

Q: Is the internal float drain option available for the series?

A: Yes, an internal float drain option is available for the Mid-Size Series. Contact ROSS Controls for the specific model numbers and flow/pressure compatibility of the internal float drain option for the series.

Q: What body and bowl materials are used in the series?

A: The body is zinc die cast. The standard bowl is aluminum with a clear nylon sight glass, allowing visual inspection of the liquid level. Bowl rings are nylon, and seals are Nitrile elastomer.

Q: Does the series require upstream filtration?

A: Upstream coarse filtration is recommended but not always strictly required. A 5-micron rated general-purpose filter installed ahead of the coalescing filter removes bulk particulate matter and protects the coalescing element from loading with solid particles, significantly extending element service life in systems with contaminated air supplies.

Q: Can the series be used with BSPP (G) threads?

A: Yes, BSPP thread versions are available. Contact ROSS Controls with the specific model number and request the BSPP thread variant, or add the appropriate prefix as specified in the ROSS Controls ordering guide for mid-size filters.

Q: How do I know when to replace the element?

A: Monitor the integral differential pressure gauge. Replace the element when differential pressure across the filter reaches the published service threshold, typically around 10 psid, or if a noticeable reduction in downstream flow or pressure is observed. Do not wait until the differential pressure gauge is fully saturated, as a heavily loaded element can begin to shed captured contamination under high differential pressure.

Installation & Maintenance Guidelines

• Mount the filter with the bowl pointing downward. Horizontal or inverted installation prevents proper condensate drainage to the bowl drain point.
• Install upstream coarse filtration (5-micron rated) before the coalescing filter when the compressed air system has high particulate loads from corroded piping, water separators, or old air receivers.
• Verify system pressure is within the rated range: up to 150 psig (10 bar) for automatic drain models and 0 to 150 psig for manual drain models.
• Monitor the differential pressure gauge during the initial operating period to establish the element service interval for the specific contamination level in your system. Replace the element when the gauge indicates the element service threshold has been reached.
• For modular assembly installation, torque coupling kits and porting blocks to ROSS-specified values. Insufficient torque can allow leakage at the modular joints; excessive torque can damage the port seals.
• When specifying the automatic drain, ensure minimum inlet pressure of approximately 30 psig (2 bar) to activate the float mechanism reliably. The float may not actuate at very low system pressures.
• Depressurize and isolate the filter completely before performing element replacement. Remove the bowl carefully to avoid spilling accumulated condensate.
• Order replacement elements by the model number specified for the bowl type in use. Standard bowl elements (R-A60F-29 for 0.3 micron; R-A60F-29E8 for 0.01 micron) and extended bowl elements (R-A60F-32; R-A60F-32E8) are different part numbers and are not interchangeable.

Warranty & Global Support

ROSS Controls provides a one-year warranty on all products, covering defects in material and workmanship from 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 (1-800-GET-ROSS) or visit rosscontrols.com for product configuration, technical support, and distributor locator services.

Technical service is available at 1-888-TEK-ROSS for application engineering support and replacement parts identification.

Download Catalog: https://www.rosscontrols.com/en/series/80-mid-size-series