ROSS Controls Silencers-Reclassifiers: Installation & Operating Instructions for 1/2, 3/4 & 1 Port Models

Overview

The ROSS Controls Inline Silencer-Reclassifier series combines exhaust noise attenuation with air reclassification in a single, compact device. Designed for installation in exhaust ports of pneumatic directional control valves and cylinders, these units convert high-velocity turbulent exhaust flow into a laminar, lower-velocity discharge while simultaneously filtering particulate from the exhaust stream.

Available in 1/2, 3/4, and 1 NPT port sizes, the Silencer-Reclassifier series is rated for inlet pressures of 5 to 150 psig (0.3 to 10 bar) and ambient/media temperatures of 40°F to 125°F (4°C to 51°C). Sintered bronze elements provide durable filtration across the operating life of the product.

Drain options include automatic drainage via a 1/8-inch tube connector (R-00184W) routed to a collection vessel, or manual drainage using a drain cock (R-103-51SP for 1/2 models; R-103-51-1/8 for 3/4 and 1 models). ROSS designed these units with straightforward maintenance in mind—element replacement kits and bowl assemblies are readily available through authorized distributors worldwide.

Key Features

Dual-Function: Silencing and Reclassification

Conventional exhaust silencers reduce noise but do nothing to reclassify high-speed exhaust air. The ROSS Silencer-Reclassifier achieves both objectives simultaneously. By passing exhaust through sintered bronze cones and a wave washer/flat washer assembly, the device diffuses flow, drops velocity, and traps particulate—all without significantly increasing back-pressure on the actuator.

Sintered Bronze Elements for Long Service Life

Sintered bronze construction provides superior mechanical strength and resistance to compressor oil contamination compared to foam or paper alternatives. The element O-ring replacement kit (Part No. 940K77 for 1/2 models; 981K77 for 3/4 and 1 models) simplifies maintenance. Elements should be replaced simultaneously when back-pressure indication appears or visible contamination is present.

Manual and Automatic Drain Options

The 1/8-inch tube connector installation (Part No. R-00184W) enables fully automatic drainage by connecting 1/8-inch OD tubing to a collection vessel. For installations where automatic drainage is impractical, a manual drain cock provides controlled, on-demand liquid removal. One drop of blue Hylomar thread sealant is applied to connector threads; torque to 55–60 in-lbs.

Technical Specifications

Specifications from ROSS official documentation (SS-F025, Document ID 170):

Construction: Sintered bronze elements
Ambient/Media Temperature: 40°F to 125°F (4°C to 51°C)
Fluid Media: Compressed air
Inlet Pressure: 5 to 150 psig (0.3 to 10 bar)
Port Sizes: 1/2, 3/4, and 1 NPT
Filter Element: Sintered bronze (two cones, replaced simultaneously)
1/2 Model Element Kit: Part No. 940K77 (Element O-Rings Replacement Kit)
1/2 Model Plastic Bowl/Gasket Kit: Part No. 982K77
1/2 Model Metal Bowl/Gasket Kit: Part No. R-ABF103-LDC
3/4 & 1 Model Element Kit: Part No. 981K77
3/4 & 1 Model Plastic Bowl/Gasket Kit: Part No. 983K77
3/4 & 1 Model Metal Bowl/Gasket Kit: Part No. R-ABMRS109-6AS
Drain Cock (1/2 Model): Part No. R-103-51SP
Drain Cock (3/4 & 1 Model): Part No. R-103-51-1/8
Tube Fitting (Automatic Drain): Part No. R-00184W
Reducer Bushing (3/4 Model only): Part No. R-0393212
Thread Sealant: Blue Hylomar (one drop on external threads)
Torque – Tube Connector / Drain: 55 to 60 in-lbs

Applications

Pneumatic Valve and Cylinder Exhaust Ports

The primary application for the ROSS Silencer-Reclassifier is direct installation into the exhaust port of directional control valves and pneumatic cylinders. On the 1/2 model, the unit installs hand-tight directly into the exhaust port of the device to be muffled. Proper thread engagement ensures an airtight seal without over-torquing the pneumatic valve body, which could cause cracking or thread damage.

Noise Control in Automated Assembly Equipment

Automated assembly equipment in automotive, electronics, and consumer goods manufacturing typically cycles pneumatic valves at very high rates. Unsilenced exhausts produce significant noise that can exceed OSHA permissible noise exposure levels. The ROSS Silencer-Reclassifier reduces exhaust noise at the source—the most cost-effective point of control—while simultaneously improving air quality by preventing contaminated exhaust from re-entering the workspace.

Safety and Compliance Standards

Always depressurize and lock out all pneumatic circuits before servicing or replacing Silencer-Reclassifier elements. The sintered elements in the 3/4 and 1 models are drop-in items; however, the internal cone and washer assembly requires precise orientation—refer to the service instructions carefully to ensure the wave washer is installed before the flat washer.

OSHA 1910.95 – Occupational Noise Exposure (relevant for exhaust noise reduction applications)
OSHA 29 CFR 1910.147 – Lockout/Tagout during servicing
Polycarbonate bowl warning: Do not use with fluids other than compressed air; replace any crazed or cracked bowl immediately
ISO 8573 – Compressed Air Purity Classes (reference for element selection)

Installation and Setup Guide

Installation procedure for ROSS Silencer-Reclassifier units:

1/2 Model: Install the Silencer-Reclassifier hand tight into the exhaust port of the device to be muffled. Do not over-torque.
3/4 & 1 Model with Manual Drain: Apply one drop of blue Hylomar to external threads of Drain Cock; install and torque to 55–60 in-lbs.
3/4 & 1 Model with Automatic Drain: Install tube fitting R-00142W (or R-00184W) into drain body; apply one drop of blue Hylomar; torque 55–60 in-lbs; attach 1/8-inch OD tubing to holding vessel.
Reassembly – 3/4 & 1 Models: Hold head upside down; drop the two cones into head. Then insert wave washer first (critical), then flat washer. Fit plastic baffle with extended tube section and O-ring into head so O-ring contacts head surface. Place bowl gasket on bowl; assemble bowl to head; tighten bowl ring clockwise.
Drain frequently; unit should be drained at regular intervals to prevent liquid buildup.
Replace both sintered elements simultaneously when back-pressure indication appears.

Why Choose ROSS Controls

For over 100 years since 1921, ROSS Controls has delivered precision-engineered pneumatic and fluid power solutions to industries worldwide. ROSS Silencer-Reclassifiers are engineered to minimize both noise and air contamination from pneumatic exhaust ports, improving workplace safety and equipment longevity. Contact ROSS at 1-800-GET-ROSS or visit www.rosscontrols.com.

Download This Document

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Frequently Asked Questions

Q: What is the inlet pressure range for the Silencer-Reclassifier?

A: The ROSS Silencer-Reclassifier is rated for 5 to 150 psig (0.3 to 10 bar) inlet pressure. Operation below 5 psig is not recommended as float drain function may be affected.

Q: Can elements be cleaned and reused?

A: No. The white sintered elements must not be cleaned—they must be replaced. Cleaning is very expensive, at best 85% effective, and may introduce additional contamination. Replace both elements simultaneously.

Q: What thread sealant should I use on the drain fittings?

A: Use one drop of blue Hylomar on the external threads of the drain fitting or tube connector. Torque to 55–60 in-lbs. Do not use PTFE tape or pipe dope, as these can migrate into the fluid system.

Q: Is the wave washer sequence important during reassembly?

A: Yes—it is critical. When reassembling the 3/4 or 1 model, the wave washer must be installed first, followed by the flat washer. Incorrect sequence prevents proper element seating and sealing.

Q: Can polycarbonate bowls be used with solvents or cleaners?

A: No. Polycarbonate bowls will deteriorate if exposed to solvents, certain compressor oils, chemical cleaners, or fumes. Replace any crazed or cracked bowl immediately. Where chemical exposure is likely, use metal bowl assemblies.

Q: Can the 1/2 model be connected to automatic drain tubing?

A: Yes. Install the 1/8-inch male connector (Part No. R-00184W) into the drain body, apply one drop of Hylomar, torque to 55–60 in-lbs, then attach 1/8-inch OD tubing routed to a holding vessel.

Q: What is the temperature limit for these filters?

A: The ambient and media temperature range is 40°F to 125°F (4°C to 51°C). Do not use in high-temperature environments; compressed air must be cooled to within this range before entering the filter.

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

A: Replace elements when back-pressure increase is indicated by downstream gauges or when obvious contamination is visible on the element surface. Replace both elements at the same time to maintain balanced flow.