Silencers Exhaust Noise Reduction

Product Overview

The ROSS Controls exhaust silencers are pneumatic noise reduction components designed to attenuate the sharp exhaust blast generated when compressed air vents to atmosphere through directional control valves, cylinders, and actuators. By fitting directly to valve exhaust ports, these silencers reduce exhaust noise levels by 17 to 25 decibels, enabling industrial facilities to achieve OSHA compliance without requiring costly structural noise abatement measures.

The Series encompasses three distinct product families: aluminum sintered-element silencers rated to 290 psig for general industrial applications, stainless steel sintered-element silencers rated to 175 psig for corrosive environments, and 316 stainless steel silencers rated to 125 psig for the most demanding washdown and chemical exposure conditions. Port sizes range from 1/8 inch to 2-1/2 inch, with both male and female thread configurations to match any valve exhaust port.

The sintered filtration element design serves a dual function: diffusing exhaust air to reduce noise and filtering particulate matter from entering the valve exhaust path. This self-cleaning characteristic extends service intervals and maintains low backpressure throughout the operating life of the component. All models are available in both NPT and R/Rp (metric) thread forms for global compatibility.

For high-cycle DM1 and DM2 Series double valve applications, ROSS offers integrated high-flow, high-reduction silencer kits that combine matched silencer performance with complete plumbing assemblies. These kits achieve the same 17 to 25 dB noise reduction while accommodating the significantly higher flow rates of large-bore double valve systems used in press and metal forming automation.

Key Engineering Features

• 17 to 25 dB Noise Reduction - Demonstrated exhaust noise attenuation across the full frequency spectrum, enabling pneumatic systems to meet OSHA dB workplace exposure limits without secondary noise barriers.
• Aluminum Construction to 290 psig - Corrosion-resistant aluminum body rated to 290 psig (20 bar) maximum for standard dry industrial environments, providing the best balance of weight, cost, and durability.
• Stainless Steel Options to 175 psig - Standard stainless steel sintered-element silencers rated to 175 psig (12.3 bar) for moisture-laden or corrosive environments where aluminum would corrode.
• 316 Stainless Steel for Washdown Service - Premium 316 stainless steel construction rated to 125 psig (8.6 bar) with nitrile seals for food processing, pharmaceutical, and marine environments requiring aggressive chemical resistance.
• Full Port Size Range 1/8 to 2-1/2 Inch - Covers all common pneumatic exhaust port sizes from small precision valves to large industrial actuators, with both NPT and R/Rp thread forms for global compatibility.
• Minimal Backpressure - Engineered sintered element design maintains system efficiency by keeping exhaust backpressure below 2 psi at rated flow, preventing degradation of valve and actuator performance.
• Self-Cleaning Sintered Element - Sintered filtration media provides self-cleaning characteristics during each exhaust cycle, extending element service intervals and reducing maintenance requirements.
• High-Flow DM Series Silencer Kits - Complete plumbing kits for DM1 and DM2 Series double valves, handling flow rates from 256 scfm (basic size 2) to 7,200 scfm (basic size 30) with all installation hardware included.
• Hex Body Design - Wrench-flat hex body enables installation and removal with standard wrenches without requiring special tools, simplifying field service in crowded machine cabinets.
• Dual-Function Element - Sintered element simultaneously reduces exhaust noise and provides particulate filtration, preventing environmental contaminants from entering the valve exhaust port.

Technical Specifications

General Specifications

Certifications & Compliance

Typical Applications & Industries

Automotive Manufacturing

• Press rooms and metal stamping lines where high-speed valve cycling generates repeated exhaust blasts exceeding 100 dB. Aluminum silencers on press exhaust ports reduce peak noise levels to below OSHA action thresholds without restricting cycle rates.
• Body shop robotic welding cells using pneumatic clamps and positioners. Silencers on the multiple solenoid valve exhaust ports cumulatively reduce ambient noise in enclosed cell areas.
• Paint shop actuators and conveyor systems where valve exhaust noise compounds with process equipment noise to exceed permissible exposure limits.
• Assembly line pneumatic tool exhausts where workers spend full shifts in close proximity to actuators cycling multiple times per minute.

Metal Forming and Stamping

• Hydraulic and pneumatic press control systems where rapid exhaust of large-bore cylinders generates impulse noise peaks. DM Series silencer kits handle the high flow rates of basic size 12 and 30 double valves at up to 7,200 scfm.
• Coil handling and transfer systems that use pneumatic actuators for part feeding, clamping, and ejection in high-speed operations.
• Forging operations where press control valves exhaust at high pressure and flow, requiring silencers rated to the full 290 psig aluminum operating pressure.

Food and Beverage Processing

• Filling lines and packaging machinery using pneumatic actuators in environments subject to daily high-pressure washdown. 316 stainless steel silencers withstand sanitation chemical exposure and moisture that would corrode aluminum.
• Conveyor and sorting systems in refrigerated areas where moisture condensation accelerates corrosion of standard aluminum silencers. Stainless steel construction maintains performance in cold and wet conditions.
• Bottling and canning lines where FDA-compliant material contact requirements mandate stainless steel hardware on any component near product contact zones.

Pharmaceutical and Life Sciences

• Clean room pneumatic actuators where regular sterilization with aggressive chemicals requires material compatibility beyond standard aluminum. 316 stainless steel sintered element silencers meet USP Class VI and FDA material requirements.
• Aseptic filling and packaging lines where exhaust ports must be sealed against contamination while maintaining clean air exhaust paths.
• Tablet press and capsule filling equipment where high-cycle pneumatic actuators require silencers that endure continuous operation with minimum maintenance.

General Industrial and Assembly

• Multi-axis assembly robots where individual joint actuators exhaust multiple times per second, and cumulative exhaust noise in the work cell exceeds OSHA limits without silencing.
• Pneumatic test stands and leak detection equipment where controlled exhaust conditions affect measurement repeatability if backpressure is not minimal and consistent.
• Outdoor machinery and construction equipment using pneumatic controls in environments exposed to rain, humidity, and corrosive industrial atmospheres.

Ordering and Model Number Configuration

Standard aluminum silencer models carry the 5500A prefix for NPT threads. Add D prefix for R/Rp metric threads (e.g., D5500A4003).

Stainless steel (sintered element) models use the 5500B prefix for NPT threads. Add D prefix for R thread variants (e.g., D5500B4004).

316 stainless steel models use the 5500A___5 number pattern. Available in 1/4, 1/2, and 1 inch port sizes.

High-flow silencer kits for DM Series double valves use the 2323H77 through 2331H77 series. Specify NPT or R thread by selecting the corresponding kit number.

Silencer flow capacity (Cv) must equal or exceed the rated exhaust capacity of the controlling valve. Undersizing creates backpressure that degrades valve performance.

ROSS also offers hex nipple connectors in steel and stainless steel for 1-1/4 through 2-1/2 inch sizes where valve ports are female-threaded.

Related Products & Accessories

• 21 Series Inline Directional Control Valves - Standard temperature and extreme temperature inline poppet valves for which the series silencers are commonly specified as companion exhaust noise reduction accessories. https://www.rosscontrols.com/en/series/2759-lowhigh-temperatures-din-m12-connection-21-series
• 91 Series Electrical Connectors - DIN EN 175301-803 Form A, B, and C connectors for ROSS solenoid valve coils. https://www.rosscontrols.com/en/series/91-electrical-connectors
• L-O-X Lockout Valves - Manual lockout and exhaust valves with integrated sensing ports, commonly paired with Series silencers on exhaust ports. https://www.rosscontrols.com/en/series/1287-lockout-valves-15-series
• DM2 Series Double Valves - Safety exhaust double valves for which high-flow silencer kits 2323H77 through 2331H77 are designed. https://www.rosscontrols.com/en/series
• 89 Series Silencers/Reclassifiers - Inline silencers/reclassifiers for ROSS air preparation filter systems, providing noise reduction and air reclassification in FRL assemblies. https://www.rosscontrols.com/en/series/89-silencers-reclassifiers

Frequently Asked Questions (FAQ)

Q: What noise reduction can I expect from the series silencers?

A: ROSS silencers achieve 17 to 25 decibels of exhaust noise reduction. The actual reduction depends on silencer size, system pressure, and exhaust flow rate. At typical industrial pneumatic pressures of 80 to 100 psig, properly sized silencers routinely reduce exhaust peaks from 100 to 110 dB down to 80 to dB.

Q: What is the maximum operating pressure for aluminum silencers?

A: Aluminum Series silencers are rated to 290 psig (20 bar) maximum operating pressure. This rating applies to all standard aluminum models regardless of port size.

Q: When should I select stainless steel instead of aluminum?

A: Select stainless steel when the installation environment involves moisture, condensation, salt spray, washdown procedures, or exposure to corrosive chemicals. Standard stainless steel silencers are rated to 175 psig. For food processing, pharmaceutical, or marine applications, 316 stainless steel provides superior corrosion resistance up to 125 psig.

Q: How do I size a silencer for my application?

A: Match the silencer port size to the valve exhaust port size. Verify that the silencer Cv rating equals or exceeds the exhaust Cv of the controlling valve. ROSS publishes Cv ratings for all silencer models. Undersizing creates excessive backpressure that reduces valve performance and shortens component life.

Q: Are both NPT and metric thread silencers available?

A: Yes. Standard models use NPT threads. Metric R/Rp thread models are identified by the D prefix added to the model number (e.g., D5500A4003 for a 1/2 inch R thread silencer). Both thread forms are available across the complete product line.

Q: What is the purpose of the sintered element?

A: The sintered filtration element serves dual functions: it diffuses the exhaust air stream to reduce acoustic energy, and it filters particulate matter from entering the valve exhaust port. The sintered porosity provides self-cleaning action during each exhaust pulse, extending service intervals.

Q: How often should silencer elements be replaced?

A: ROSS recommends annual element replacement in clean, dry environments. In dusty, contaminated, or wet environments, monthly visual inspection is required, with replacement whenever elements appear clogged or damaged. Increased backpressure during valve operation is a reliable indicator that element replacement is needed.

Q: Do high-flow silencer kits fit the DM2 Series double valves?

A: Yes. The DM Series silencer kits (2323H77 through 2331H77) are specifically engineered for DM1 and DM2 Series double valves in basic sizes 2 through 30. Each kit includes all plumbing hardware for installation and is rated to 125 psig maximum. Flow capacity ranges from 256 scfm for basic size 2 to 7,200 scfm for basic size 30.

Q: Can these silencers be used on other manufacturers valves?

A: Yes. ROSS silencers use standard NPT and R/Rp thread configurations compatible with pneumatic components from all major manufacturers. Select the model matching the exhaust port size and thread form of the valve being silenced.

Q: Will a silencer affect valve response time?

A: A properly sized silencer with adequate Cv rating has negligible effect on valve response time. Undersized silencers create backpressure that can slightly increase exhaust-phase response time. Select a silencer with a Cv equal to or greater than the valve exhaust Cv to avoid this effect.

Q: What are the temperature limits for the series silencers?

A: Standard aluminum and stainless steel silencers are rated for ambient and media temperatures in the range typical of filtered compressed air systems. The 316 stainless steel models with nitrile seals are suitable for continuous service at temperatures within the nitrile seal compatibility range. Contact ROSS for applications above 175F or below 40F.

Q: Are replacement elements available separately?

A: Yes. ROSS offers replacement sintered elements for all Series silencer models. Contact ROSS Controls or an authorized distributor with the silencer model number to obtain the correct replacement element.

Installation & Maintenance Guidelines

• Verify that the silencer Cv rating equals or exceeds the exhaust flow capacity of the controlling valve or cylinder at maximum operating pressure.
• Thread the silencer directly into the valve exhaust port using the hex body for wrenching. Do not over-tighten; finger-tight plus 1 to 2 turns with a wrench is sufficient.
• Orient silencers to allow gravity drainage of condensate from the sintered element. Avoid inverted installation positions that trap moisture.
• Inspect elements visually each month in dusty environments. Replace annually in clean environments or when backpressure increases noticeably during valve operation.
• Do not paint or coat sintered elements, as this blocks the porous filtration media and eliminates noise reduction performance.
• For 316 stainless steel models in contact with food products, verify chemical compatibility of nitrile seals with cleaning agents used in the facility.
• High-flow DM Series silencer kits include all plumbing required for installation. Follow kit-specific installation instructions to ensure proper porting and sealing.
• When replacing elements, verify that the replacement part number matches the original to ensure correct filtration rating and physical fit.

Warranty & Global Support

ROSS Controls provides a one-year warranty on all Series 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) GET-ROSS (1-800-438-7677) or visit rosscontrols.com for product selection guidance, technical support, and distributor locator services.

For complete technical data and dimensional drawings, visit the ROSS Controls product page or request the ROSS Silencers catalog.

Download Catalog: https://www.rosscontrols.com/en/documents/1769/pneumatic-exhaust-silencers