Diaphragm Compressors

In diaphragm compressor systems, the flow of fluid through the suction and discharge valves is intermittent, resulting in periodic pressure fluctuations which are known as acoustical pulsation. The magnitude and shape of this pulsation are influenced by the physical, geometrical, and mechanical characteristics of the compressor system.

The acoustical pulsation analysis involves calculating pressure pulsations, pulsation-induced shaking forces, and pressure drops resulting from the specific attenuation measures. Typical attenuation strategies include design of pulsation suppression devices and/or orifice plates and modification of piping layouts. By performing an acoustical pulsation analysis to optimize these measures, the pressure pulsations, shaking forces, and pressure drops can be reduced to levels within the API 618 pulsation guidelines.

An example of acoustical pulsation analysis for a diaphragm compressor package with the following specifications is illustrated below. The analysis was performing using Bentley PULS XM Option 3 software in accordance with the API 618 Standard.

The calculated acoustical pulsations, represented by the maximum pulsation violation ratio, for the inter-stage system of compressor package, both before and after design modifications, are shown in the following figures. The design modifications aim to implement pulsation attenuation measures which include the design of appropriate pipe layout and the pipe expander to mitigate excessive pulsations and shaking forces.