Silencers

Large flows and short cyclesIf you have large cylindersWhen silencing valves that create especially strongimpulse flows (large volumes for a short time), it isimportant that there is volume between the valve andthe silencer to even out the pulse. Normally, hoses andcoupling manifolds provide the desired volume.However, for special cases with exceptionally largeflows, the expansion silencer has been developed.Expansion silencers are available for connections withdiameters of up to Ø 2”.Use the table on page 4.4 to decide which silenceryou should install.Expansion silencers are particularly suitable for systemswith the following characteristics:• Large flows• Short cycles• Sensitivity to backpressureIf you have quick evacuation valvesTo attain faster cylinder function, quick evacuation valvesare sometimes used. As a rule, these valves generatelarger flows than ordinary valves of the same connectiondimension. Therefore, when connecting valves to asilencer, it is advisable to watch for reduced cylinderspeed or overloading of the silencer.It may be necessary to increase the number of silencersand mount them in parallel.If you have punch pressesMany punch presses are equipped with so called pneumaticengagement. After a punch stroke has been initiated,the engagement mechanism is evacuated in order tostop the punch. If evacuation is impeded, there is a riskof double punching. For this reason, modern silencersmust be fitted with a relief valve that opens if backpressureshould become too great.To achieve satisfactory noise suppression, exhaust shouldbe connected to an expansion tank whose volume is 5 to10 times that of the engagement mechanism. Air fromthe expansion tank is then discharged to one or severalcentral silencers, depending on the size of the press.4.6 www.silvent.com