Vent Silencers

	Vent Silencers
	VSR Rectangular Vent Silencers VSC Circular Vent Silencers
	J. P. America Inc. absorptive Type VSC circular silencers, and Type VSR rectangular silencers, offer the most compact and effective attenuation of vent noise possible. Designed specifically for the high velocity discharge of air, steam, and other gases to atmosphere, both types are ruggedly built to ensure dependability and long life. Both can be used in continuous or intermittent service.

	J.P. has established itself as a supplier of highly engineered silencing and isolation products for industry. Our corporate philosophy of providing our customers with the service expected and the products needed has made this possible. We guarantee this same level of service and product integrity in our VSC and VSR vent silencers.
	VSC Vent Silencers Annular flow circular design Discharge flows up to 175,000 acfm Maximum pressure drop of 5.5 psi across silencers Sizes for 4" dia. inlet connections and up Ideal for mid and high band noise attenuation VSR Vent Silencers Parallel baffle rectangular design Discharge flows up to 575,000 acfm Maximum pressure drop of 5.5 psi across silencers Sizes for 4" dia. inlet connections and up Increased low band attenuation due to parallel baffle design Construction VSC and VSR silencers are ruggedly designed to withstand the high impact forces of gas discharge complete with inlet diffusers for the absorption of energy. Acoustical treatment is high temperature, non-flammable, moisture resistant fill packed under compression. A layer of fiberglass cloth, stainless steel mesh, and mild steel perforated plate separates the media from the air stream to eliminate the possibility of leaching. Casings are fabricated from heavy gauge mild steel with continuously welded seams. Pre-drilled 125 # ASA flanges are provided for inlet connection and all silencers are supplied with threaded and capped drains. Each silencer is given an exterior coat of high temperature paint prior to shipment. Silencers can be supplied for vertical or horizontal discharge with either in-line or side inlet connections. A wide range of options are available including; special materials and finishes, mounting feet and suspension lugs, custom inlet connections, weather hoods, etc. Your J.P. representative has full information on all of these. Vent Silencer Selection The chart and steps listed below can be used to select the appropriate VSC or VSR vent silencer for the job.



	Step 1: List the valve PWL (sound power level) values. These values, in decibels (dB re 10-'2 Watts), should be available from the manufacturer or from standard industrial source. Step 2: Correct for the effect of distance and room characteristics. If a free field situation exists with noise radiating hemispherically (which is often the case) apply the following distance in each octave band. Distance Correction = -20 Log r + 2.5 dB where r is the distance from noise source in ft. Directivity Correction Chart Step 3: If the distance from the noise source is over 100 ft. apply an atmospheric absorption correction using the table below. Atmospheric Absorption Correction Step 4: Sum the values from Step 1 to Step 4 to obtain the unsilenced valve SPL (sound pressure level) in dB (reference 2 x 10~N/ m2). Step 5: Insert the maximum permitted SPL levels (dB or dBA). These values may involve individuals who must work in close proximity to the valve during discharge or may be based on residential noise levels caused by the valve. Step 6: Subtract the unsilenced valve SPL levels (Step 5) from the maximum permitted SPL levels (Step 6) to get the required dynamic insertion loss tor the vent silencer.

	Contact Us:
	J.P. America Inc. 225 Industrial Drive, Unit 6, Hampshire, IL. USA, 60140 847.683.7067 1.800.445.HUSH (4874) Fax: 847.683.7069 Email: jpa@jpamericainc.com