CE4003S6B1 Emerson Power/Controller Modular Subsystem

Description

To obtain the desired results, restrictions must be sized and spaced in the primary cage wall so that the noise generated by jet interaction is not greater than the summation of the noise generated by the individual jets. This trim design can reduce the valve noise by as much as 30 dBA. The final design shown uses a combination of several noise reduction strategies to reduce valve noise up to 40 dBA.

Those strategies are: Unique passage shape reduces the conversion of total stream power generated by the valve into noise power. Multistage pressure reduction divides the stream power between stages and further reduces the acoustic conversion efficiency. Frequency spectrum shifting reduces acoustic energy in the audible range by capitalizing on the transmission loss of the piping. Exit jet independence is maintained to avoid noise regeneration due to jet coalescence.

Velocity management is accomplished with expanding areas to accommodate the expanding gas. Complementary body designs prevent flow impingement on the body wall and secondary noise sources. For control valve applications operating at high pressure ratios (∆P/P1 > 0.8) the series restriction approach, splitting the total pressure drop between the control valve and a fixed restriction (diffuser) downstream of the valve can be effective in minimizing noise. To optimize the effectiveness of a diffuser, it must be designed (special shape and sizing) for each given installation so that the noise levels generated by the valve and diffuser are equal. Figure 5.11 shows a typical installation. Control systems venting to atmosphere are generally very noisy because of the high pressure ratios and high exit velocities involved.

Dividing the total pressure drop between the actual vent and an upstream control valve, by means of a vent diffuser, quiets both the valve and the vent. A properly sized vent diffuser and valve combination, such as that shown in Figure 5.12, can reduce the overall system noise level as much as 40 dBA.

Decreases capital equipment costs Full system modularity. The Traditional I/O subsystem was designed with your investment in mind. All components are fully modular and may be installable under power.1 You add I/O interface carriers and I/O interfaces in groups of 4, 8, 16, or 32 channels as you need them. The modular design enables you to purchase the exact amount of I/O cards, 8-wide carriers, power/controllers, and 2-wide carriers you need and add more DeltaV I/O as your system grows.