Pressure pulsations testing

Pump Flow Accuracy and Pressure Pulsation Tests 7... 

Note Do not use a commercial back-pressure device for this test, as this may dampen the true pressure pulsations arising from the pump. 

It is recommended that OQ test the following on an HPLC system flow accuracy, pump compositional accuracy, pressure pulsations, column oven temperature accuracy/stability, detector noise/drift and wavelength accuracy, autosampler injection precision and carryover. 

The design of thickwalled components for pulsating pressure is based on the stress calculation with analytical or numerical methods and the determination of the maximum equivalent stress in relation to the admissible stresses at uniaxial conditions. The latter have to be extracted from Woehler-tests with specimen. If the stresses yield too large at load conditions including a safety factor, the design must be optimized by avoiding the major stress concentrations at bore intersections. The avoidance of T-intersections is reducing stresses by factor 2-3 (Fig. Id). 

The corrosion fatigue data from uniaxial tests can be transmitted to the notched pulsating pressure loaded components quantitatively or with additional safety. The uniaxial pulsating stress yields to be the stricter criterion. 

The data in Table 14.1 are taken from a typical test chart, and it shows readings of pulsation pressure test failure details torque to tighten gasket in place torque at end of test (release torque) plate thickness bead heights at start and finish, giving compression set number of cycles completed did gasket leak Condition of gasket at conclusion. 

The performance in pulsating pressure tests of the new material is superior to the old. Figure 14.9 shows a comparison of some 4068 variants with 4019. The superiority of the 4068 is clear. 

Pulsation Pressure 0-5000 psi Thin Plate Test Fixture Shading Denotes Failure on Test... 

Fig. 22.4 Experimental test rig for the similarity trials of laminar thread breakup under the influence of cross-wind flow. The liquid is pumped (i) from the collective tank (2) to the buffer tank (i) where pulsations are damped. Different capillary (4) configurations were used within this work including different diameters and inclination angles a. The capillary is mounted in the gas flow channel (5) made by PMMA. An axial fan (6) providing under-pressure controls the air velocity. Behind the flow, a light panel is installed and in front of it a CCD camera is placed [33]...

Components of the instrnment Primary sensing elements are prone to failures due to extreme conditions. E.g. in pressure transmitters overpressure stresses caused by pulsation or by hydraulic testing without isolation. Diaphragm seals with filled systems may slowly leak. Drifting occurs if excessive vacuum conditions arise. See manufacturer s limiting conditions for diaphragms. 

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