Product Description

The RISY/SDY 4″ flanged silencer

The silencer can be used on either the inlet or discharge side of the blower and should be located as close as possible to the blower connections.

Universal Blower Silencers - RIS SD Typical Attenuation Curve

Inlet Flow Rating: 480 CFM
Discharge Flow Rating: 735 cfm at 15 psig (flow based on inlet flow)
Maximum Temperature: 325 °F
Housing Diameter (ID): 10″
Overall Length: 42.5″
Weight: 59 lbs (26.8 kg)
This threaded silencer can be shipped via UPS.

RISY/SDY-4F “Y” Dimension
The standard Y dimension for the RISY/SDY-4 is 7.5″. Larger dimensions up to 16.5″ are available for an additional charge and extended lead time.



Paint and Coating Options
Silencers are shipped with the manufacturer’s standard blue primer coat.  For a durable, long lasting finish, pdblowers can apply special coatings with additional cost and lead time.  Our most common option includes a primer coat of Sherwin-Williams KEM KROMIK, a rust inhibiting, corrosion resistant phenolic alkyd resin primer, followed by a finish coat of Sherwin-Williams SHER-KEM® high gloss metal finishing enamel.  Contact us to discuss special coatings.

Air Tightness
Standard industrial silencers are generally not individually leak tested and occasionally very small pin-holes may appear in welds. Because of the small size of these pin-holes, their effect on typical pressure or vacuum conditions is insignificant. If 100 percent air tightness is essential for gas service or other special applications, with additional cost and lead time the manufacturer will perform a 7 PSIG leak test. Contact us if you need this service with your order.


RISY/SDY-4 Flanged Silencer

BOM Number: 54-204-AA SKU: 22140 Category:


Heavy-duty all welded unit
Chamber-absorptive type
Pitch line speeds above 3300 FPM
Typically not kept in stock, 1 wk lead time

Shipping Weight: 65 lbs
Shipping Dimensions: 45 × 12 × 19 in

Universal Silencer

Connection Type:


Connection Size:

4" Flanged

Max Flow:

480 CFM

Silencer Type:

Chamber Absorptive