Beta scan plot

The indicator card is the only real way to monitor reciprocating-com-pressor performance. Typically, the equipment and personnel to generate the card can be obtained from a local company specializing in this service. Often, the indicator card is referred to as a beta scan plot. 

The Beta Scan plot obtained from the No. 2 cylinder crank end is shown in Figure 25-9. This plot shows the valve installed in this cylinder end was experiencing a 25%-30% loss in compression work. 

The area encompassed by the Beta Scan plot is proportional to the compression work performed by the piston. Unfortunately, not all of this work is of use in moving gas. For instance, the top horizontal line shown in Figure 25-9 is the compressor discharge pressure. The area of the plot above this line is wasted compression work caused by ... 

FIQURE 25-8 Beta Scan plots are a powerful troubleshooting tool. 

FIGURE 25—9 Beta Scan plot defines compressor efficiency. 

One way to discriminate between the possible problems is to perform a Beta Scan survey of the compression cylinders. A Beta Scan is a pressure-volume diagram describing the actual compressor cylinder end performance. The pressure inside the cylinder is plotted against the piston position. A piston position of 0% corresponds to the piston position closest to the cylinder head. A perfect pressure-volume diagram is shown in Figure 25-7 This is the Carnot Cycle. Figure 25-8 shows Beta Scans for several maladies affecting compressor valves. 

Fibers and base resins are supplied against certificates of conformance and often property test certificates. On-line control during the manufacture of prepreg revolves around the correct ratio of fiber to resin. This is done by a traversing Beta-gauge, which scans the dry fiber (either unidirectional of fabric) and then the impregnated fiber and provides a continuous real-time plot of the ratio across the width of the material. This can be linked back to the resin system application point for continuous adjustment. 

The XRD patterns of the Cu/beta catalyst as a function of temperature/time interval are plotted in Fig. 5.2. At temperatures below 800 °C (Scan number = 16 in Fig. 5.2), the change in intensity of all the diffraction peaks that correspond to the beta zeolite framework structure follows nearly the same trend as seen on the parent beta zeolite. Above this temperature however, the intensity of all peaks decreases rapidly. The zeolite crystalline structure completely collapses and... 

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