Flowserve Gaseous Noise Control - PRO-QUIP

6. Type III 7. Type IIIntroductionUsing the same skirt guided drilled-hole plug as the Type II designand a heavy duty drilled-hole cage, the Type III design iscreated (Figure 6.1: Type III Trim). The Type III system is mosteffective at reducing noise generated by higher pressure drops.The Type III trim offers one or two stages of pressure reductionin a heavy duty design.DesignWhen using two stages of pressure drop, the Type III designhas a skirt guided drilled-hole plug, and a heavy duty drilledholecage. In the single stage style, the heavy duty drilled-holecage is used. Both styles use cage guiding to throttle each stagefor effective noise control over the complete range. Each stagetakes part of the pressure drop to produce the minimum noisewhile still attenuating noise generated upstream. Both designwork by attenuating upstream noise and shifting the noise frequencyhigher.Standardized designs allow for quicker deliveries and lowercosts.Base Valve DesignAvailable in a number of Kammer platforms, the most commonlyused is the 35000 series control valve.Mechanisms at Work• Pressure Control• Velocity Control• Attenuation• Frequency ShiftingFigure 6.1: Type III TrimIntroductionBy adding a skirt guided drilled-hole plug to the attenuators usedin the Type I design, the Type II design is created (Figure 7.1: TypeII Trim). The Type II system is most effective at reducing noisegenerated by moderate to high pressure drops. The Type II trimoffers up to four stages of pressure reduction.DesignWhen using all four stages of pressure drop, the Type II designhas a skirt guided drilled-hole plug, an inner perforated metalstage, a metal mesh silencer and an outer perforated metalstage. Each stage takes part of the pressure drop to produce theminimum noise while still attenuating noise generated upstream.When only a single stage is required, the skirt guided drilled-holeplug is used. The three stage design uses a skirt guided drilledholeplug along with both the inner and outer stages of the cage.Adding the baffle creates the four stage style. All three designswork by attenuating upstream noise and shifting the noise frequencyhigher.Standardized designs allow for quicker deliveries and lowercosts.Base Valve DesignAvailable in a number of Kammer platforms, the most commonlyused is the 35000 series control valve.Mechanisms at Work• Pressure Control• Velocity Control• Attenuation• Frequency ShiftingFigure 7.1: Type II Trim14