Silencers / Reclassifiers Reclassifiers

Product Overview

The ROSS Controls Silencers/Reclassifiers are inline filtration and noise reduction components designed specifically for integration with ROSS air preparation filter systems. Unlike the 90 Series exhaust silencers that mount on valve exhaust ports, the series silencers/reclassifiers are installed within filter assemblies or at filter exhaust points to simultaneously reduce noise and reclassify exhaust air within compressed air treatment systems.

The Series provides enhanced performance for 1/4-size filters when used as companion components with ROSS FULL-SIZE, HIGH-CAPACITY, MD3, and MD4 filter units. The inline design with sintered bronze filtration elements provides noise attenuation, air diffusion, and filtration, making these components appropriate for applications where exhaust air from filter/regulator/lubricator systems must be quietly and cleanly discharged.

Three port sizes are available: 1/2 inch, 3/4 inch, and 1 inch NPT. Each model includes a polycarbonate bowl with an integrated metal bowl guard for protection against physical damage while maintaining visual inspection capability for condensate levels. The sintered bronze element performs self-cleaning filtration during normal operation, with replacement elements available for scheduled maintenance.

For installations requiring automatic condensate drainage, the 1076K77 auto-drain conversion kit adapts a standard bowl to accept an auto-drain unit, enabling unattended automatic water removal from the filter. This kit is available for FULL-SIZE filter units only. The combination of inline silencer/reclassifier with automatic drain capability supports continuous operation environments where manual drain intervention is not practical.

Key Engineering Features

• Inline Silencer and Air Reclassifier Function - Simultaneously performs noise reduction and air reclassification in a single component, diffusing exhaust air while filtering particulate matter to reduce the velocity and acoustic energy of discharged air streams.
• Compatible with FULL-SIZE, HIGH-CAPACITY, MD3, and MD4 Filter Units - Engineered for integration with major ROSS air preparation filter product families, providing the same manufacturer compatibility in the FRL system as the filter components themselves.
• Sintered Bronze Filtration Element - Sintered bronze element provides durable self-cleaning filtration with typical filtration rating of 20 micron (1/2 inch) or 100 micron (3/4 and 1 inch), extending service intervals while maintaining consistent performance.
• Polycarbonate Bowl with Metal Guard - Transparent polycarbonate bowl allows visual inspection of condensate level for manual drain models without disassembly, while the metal bowl guard protects against physical impact that could shatter an unguarded polycarbonate bowl.
• 1076K77 Auto-Drain Conversion Kit - Converts a standard filter bowl to accept an automatic drain unit for unattended condensate removal. Available for FULL-SIZE filter units, enabling continuous operation in automated systems without manual drain servicing.
• Three Port Sizes (1/2, 3/4, 1 inch NPT) - Port sizes cover the primary FRL filter size range, with flow capacities matched to the upstream filter performance to avoid creating a flow bottleneck in the air preparation system.
• NPT and BSPP Thread Options - Standard models use NPT port threads. For BSPP (metric) thread versions, add a C prefix to the model number (e.g., C5055B4009), maintaining global system compatibility.
• Replacement Element Availability - Sintered bronze replacement elements are catalog items (940K77 for 1/2 inch, 981K77 for 3/4 and 1 inch), ensuring long-term serviceability without replacing the complete silencer assembly.
• Low Pressure Drop Design - Operating pressure range of 5 to 150 psig (0.3 to 10 bar) with inlet pressure requirements typical of standard industrial compressed air systems, maintaining sufficient system pressure while providing effective noise reduction.
• Self-Cleaning Sintered Element - Sintered bronze construction provides self-cleaning characteristics during normal flow conditions, reducing maintenance frequency compared to paper or fiber element alternatives.

Technical Specifications

General Specifications

Certifications & Compliance

Typical Applications & Industries

Compressed Air Treatment Systems

• ROSS FRL (Filter-Regulator-Lubricator) systems installed at machine supply points where the filter exhaust or vent must be noise-attenuated. The Series silencer/reclassifier reduces the noise from auto-drain exhaust cycles and filter backflush events that would otherwise produce sharp pressure release sounds.
• Centralized air preparation stations serving multiple machine zones where the series inline silencer reduces the accumulated noise from filter drain events in open factory areas near worker stations.
• Clean room air preparation where the silencer/reclassifier both reduces noise and filters exhaust air to prevent re-introduction of particulate matter back into the controlled environment air space.

Food and Beverage Processing Air Preparation

• Food processing line FRL systems where filter condensate drain exhaust must be contained and silenced in areas adjacent to open product. The Series reclassifier contains the exhaust air discharge and filters it before release, preventing direct air blast contamination of product zones.
• Beverage bottling and filling line air preparation where regular filter drain events would otherwise create objectionable noise in otherwise quiet processing areas or near regulatory-controlled noise zones.
• Refrigerated food processing environments using ROSS air preparation systems where polycarbonate bowl visibility allows operators to monitor condensate accumulation during cold line operation without opening enclosures.

Pharmaceutical and Life Sciences Manufacturing

• Clean process air systems where FRL exhaust air must be filtered before discharge to avoid introducing particles into sensitive manufacturing areas. The 20-micron sintered bronze element filters the exhaust air stream during drain events.
• Validated pneumatic systems where component specifications must be fully documented for regulatory compliance. ROSS models provide the same manufacturer traceability as other ROSS air preparation components in the validated system.
• Isolator and cleanroom air supply systems where filter exhaust must be managed to maintain room pressure balance and air quality standards.

Industrial Automation and Assembly

• Multi-zone pneumatic supply systems using ROSS FRL assemblies at zone entry points where filter auto-drain noise would accumulate across dozens of units in large manufacturing areas.
• Robot and servo system air supply stations where filter exhaust noise reduction contributes to overall cell noise management alongside valve and actuator silencers.
• Assembly line air preparation panels in enclosed machinery alcoves where noise levels in the panel enclosure affect nearby worker exposure levels.

Outdoor and Environmental Applications

• Outdoor pneumatic control panels where FRL filter drain exhaust is controlled and diffused by the silencer/reclassifier, preventing wind-driven back-pressure effects on filter drain operation.
• Mobile and portable compressed air systems where the combined silencer/reclassifier reduces both noise and visible air discharge from filter systems in areas where visible exhaust would be undesirable.
• Pipeline control and compressor station air preparation systems where noise reduction from filter exhaust is a site regulatory requirement in populated areas.

Ordering and Model Number Configuration

Standard NPT thread models: 5055B4009 (1/2 inch), 5055B5009 (3/4 inch), 5055B6009 (1 inch).

For BSPP (metric) threads, add C prefix: C5055B4009, C5055B5009, C5055B6009.

For auto-drain conversion on FULL-SIZE filter models only: order 1076K77 kit separately.

Replacement sintered bronze elements: 940K77 for 1/2 inch models, 981K77 for 3/4 and 1 inch models.

Verify polycarbonate bowl suitability for the ambient temperature. Polycarbonate bowl models are rated to 125F (51C) maximum. For higher temperature applications, consult ROSS for metal bowl availability.

The Series is distinct from the 90 Series: Series is for FRL filter system integration; 90 Series is for direct installation on pneumatic valve exhaust ports.

Related Products & Accessories

• 90 Series Exhaust Silencers - Aluminum and stainless steel exhaust silencers for direct installation on pneumatic valve exhaust ports, distinct from the series FRL silencers. https://www.rosscontrols.com/en/series/90-silencers
• ROSS Air Preparation Filters - FULL-SIZE, HIGH-CAPACITY, MD3, and MD4 filter units for which the series silencers/reclassifiers are designed as companion components. https://www.rosscontrols.com/en/series
• 91 Series Electrical Connectors - DIN EN 175301-803 connectors for ROSS solenoid valves in the same air preparation and pneumatic control system. https://www.rosscontrols.com/en/series/91-electrical-connectors
• 94 Series Pop-Up Visual Indicators - Energy release verification indicators for ROSS L-O-X lockout valves, used in the same pneumatic system as FRL components. https://www.rosscontrols.com/en/series/94-pop-up-visual-indicators
• 95 Series Mechanical Pressure Switches - Electrical pressure switches for energy release verification, complementing the FRL air preparation system components. https://www.rosscontrols.com/en/series/95-mechanical-pressure-switches

Frequently Asked Questions (FAQ)

Q: What is the difference between the series silencer/reclassifier and the 90 Series exhaust silencer?

A: The Series silencers/reclassifiers are designed for integration with ROSS air preparation filter systems (FRL), providing noise reduction and air reclassification at filter exhaust and drain points. They include a polycarbonate bowl with metal guard for condensate collection. The 90 Series exhaust silencers are individual components that mount directly on pneumatic valve or actuator exhaust ports for valve exhaust noise reduction. The two series serve different installation contexts within a compressed air system.

Q: What does air reclassification mean in the context of the series?

A: Air reclassification refers to the process of diffusing and filtering the exhaust air stream from a filter or drain point, changing the character of the discharged air from a high-velocity directed stream to a low-velocity diffused release. This process reduces noise, prevents direct air blast in sensitive areas, and can reduce the acoustic classification of the discharge area from high-noise to acceptable noise levels per OSHA standards.

Q: Which filter series are compatible with the series silencer/reclassifier?

A: The Series is designed for use with ROSS FULL-SIZE, HIGH-CAPACITY, MD3, and MD4 filter unit series. It provides enhanced performance specifically for 1/4-size filters within these family groups. Verify port size and thread compatibility with the specific filter model before ordering.

Q: Is the 1076K77 auto-drain kit compatible with all filter units?

A: No. The 1076K77 auto-drain conversion kit is available for FULL-SIZE filter units only. It is not compatible with HIGH-CAPACITY, MD3, or MD4 filter models. Contact ROSS to confirm availability of auto-drain conversion kits for other filter series.

Q: What is the maximum operating pressure for the series?

A: The Series silencer/reclassifier is rated for inlet pressures from 5 to 150 psig (0.3 to 10 bar) with the polycarbonate bowl. Do not exceed 150 psig to avoid bowl stress. For systems operating above 150 psig, contact ROSS about metal bowl alternatives.

Q: What is the temperature limit for the polycarbonate bowl version?

A: The polycarbonate bowl is rated for ambient and media temperatures of 40 to 125F (4 to 51C). For installations where compressed air or ambient temperatures exceed 125F, a metal bowl option may be available. Contact ROSS for applications requiring elevated temperature capability.

Q: Can I use the series with non-ROSS filter systems?

A: The Series models use standard NPT (or optional BSPP) port threads compatible with filter exhaust ports of similar port sizing from other manufacturers. Verify port size, thread type, and flow capacity requirements before applying Series components to non-ROSS filter systems.

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

A: Replace elements annually in clean environments. Earlier replacement is indicated by: visible darkening or clogging of the element during inspection, reduction in system flow below normal operating values, or increase in noise level from the filter exhaust. Remove the bowl, inspect the element, and replace with 940K77 (1/2 inch) or 981K77 (3/4 and 1 inch) as needed.

Q: Does the metal bowl guard need to be removed for element inspection?

A: The metal bowl guard design allows bowl removal for element inspection without permanent removal of the guard from the installation. The guard protects the polycarbonate bowl while allowing the bowl to be rotated off for service. Refer to the specific filter assembly instructions for the exact bowl removal procedure.

Q: What is the flow limitation for the 1/2 inch model?

A: For the 1/2 inch 5055B4009 model, effluent air re-entrainment may occur at flow rates above 70 scfm (33.0 l/s). Above this flow rate, discharged air may be re-drawn back into the silencer element. Size the system to keep normal operating flow below 70 scfm for the 1/2 inch model.

Q: Are BSPP versions available in all three port sizes?

A: Yes. BSPP thread versions are available for all three port sizes by adding the C prefix to the model number: C5055B4009 (1/2 inch), C5055B5009 (3/4 inch), C5055B6009 (1 inch). Contact ROSS Controls for availability.

Q: Where do I find installation instructions for the series?

A: Installation instructions and the product catalog for the series are referenced on the ROSS Controls series page at rosscontrols.com/en/series/89-silencers-reclassifiers. Contact ROSS Controls at 1-800-GET-ROSS for technical documentation.

Installation & Maintenance Guidelines

• Install the series silencer/reclassifier at the exhaust port or drain port of the FRL filter unit per the FRL installation instructions. Ensure thread engagement is sufficient for leak-free sealing without over-tightening the polycarbonate housing components.
• Orient the polycarbonate bowl downward when possible to allow gravity drainage of condensate to the drain point. The metal bowl guard protects the bowl from accidental impact during installation and operation.
• For auto-drain conversion using the 1076K77 kit, follow the kit installation instructions specific to the FULL-SIZE filter model. Verify that the auto-drain opens and closes correctly after installation by simulating condensate accumulation or using the manual test function if available.
• Replace sintered bronze elements (940K77 or 981K77) annually in clean, dry environments, or when visual inspection shows discoloration, clogging, or when upstream filter pressure drop increases above normal operating levels.
• Do not exceed the 150 psig (10 bar) maximum inlet pressure. Verify system supply pressure is within the 5 to 150 psig operating range.
• In dusty environments, inspect and replace elements more frequently. Monthly visual checks of element condition and bowl condensate level are recommended for high-contamination installations.

Warranty & Global Support

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

Customer Service: 1-800-GET-ROSS; Technical Service: 1-888-TEK-ROSS.

Product catalogs and installation instructions are available at rosscontrols.com/en/series/89-silencers-reclassifiers.

Download Catalog: https://www.rosscontrols.com/en/series/89-silencers-reclassifiers