A study on the pressure gradient effect due to a leak in a pressure calibration system

Abstract

Leaks in a pressure calibration system should be as small as possible in order to reduce the pressure difference between the pressure standard and the device under test (DUT). However, a pressure calibration system that is perfectly sealed from the external environment does not exist, and a pressure difference due to leakage can affect the calibration results. This type of effect should be evaluated precisely because DUTs, such as precise digital pressure gauges with resolutions of less than 1 part in 106, are used widely in industry and the pressure difference due to the leak effect is expected to be larger than the resolution of the DUTs. In addition, precise digital pressure gauges for intercomparisons have been used as transfer standards to determine the degree of equivalence of pressure measurement standards among national measurement institutes (NMIs). This paper explores the leak effect using a leak control valve when a precise digital pressure gauge is calibrated using a pressure balance up to 100 kPa in an absolute mode. Experiments were performed according to an applied pressure, leak amount, tube length and pressure media. It is concluded that the uncertainty caused by a possible leak should be included in the uncertainty evaluation of the calibration results.

Calibration approach to quantify nonlinearity of MEMS pore pressure sensors using optimal interpolation

“…For optimality criterion points, a R programming package called imperialist competitive algorithm optimal designs (ICAOD) is used based on new optimization algorithm of ICA [96]. This method developed by Atashpaz-Gargari and Lucas using the socio-political process of humans in which a government or culture have tendency to extending its power and rule beyond of its own boundaries [97]. The algorithm's functionality is also demonstrated by proving its ability to integrate with a local search to find optimal designs under a more complicated criterion, such as standardised maximin optimality [93].…”

“…Imperialistic competitions among these empires make an elimination process in which weak empires collapse and powerful ones take possession of their colonies. Total power of each empire is calculated by [97]:…”

“…The sole remaining empire is an ideal world in which the power of all the colonies and imperialist is equal and they are all the optimum solution. This is the basis of the ICA for the search toward the powerful countries or the optimum points [97,98]. The algorithm can be stopped by defining a convergence condition such as certain number of iterations, running time, lower efficiency boundary.…”

“…The algorithm can be stopped by defining a convergence condition such as certain number of iterations, running time, lower efficiency boundary. The ideal stopping criterion is when all empires have collapsed and only one empire remains [94,97]. The convergence curves for designing optimum set of points are shown in figure 5.…”

Position control for the MSL Kibble balance coil using a syringe pump

“…We note that this method could be considered to introduce a controlled leak into the system between the pressure balance and the differential pressure transducer, which is not usually recommended, [14]. In this situation, the pressure in the tubing is very close to ambient pressure and the tubing volume is as small as practicable, which will reduce the effect of the leak.…”