Variable area flow meters or rotameters have been widely used for flow monitoring of industrial process, particularly where the cost is the first priority. However, with the constant demands for process digitization, remote data transmission, data log, flow level register and alarm triggered automation have been highly demanded. These characters are not available for the rotameters while the low cost barrier prevents other existing technology to provide the same solution. MEMS mass flow technology on the other hands, is ready to emerge for these applications. In this paper we present the working principle, design and performance of a series of MEMS flow meters that can be used to replace the rotameters. The all new digital flow meters meet all current digitization requirements while excel in performance at a very competitive cost.

The liquid piston provers have been widely used as the primary standard for liquid flow measurement. There are many flowmeters which can be used with the prover such as turbine flowmeters, variable area flowmeters, electromagnetic flowmeters, etc. The flowrates from the prover are measured by volumetric method. Thus, the displaced volume of water and the moving distance of the piston during measurement are the key factors. In order to receive the accurate volume, the efficient system for gaining pulses from the linear encoder is needed. Also, temperature and pressure of liquid inside the piston cylinder and the environmental conditions are involved with the measurement. Recently, the piston prover at NIMT had been upgraded by replacing the out-of-date control system and modifying the key equipments; linear encoder, PT-100 and digital manometer. Moreover, the well-known method called ‘water draw’ has been brought to verify the new system and provides the piston prover constant value. The uncertainty of the system is evaluated and reported as 0.07% (k = 2).

In 2000, Micro Motion, Inc. presented a paper at FLOMEKO introducing a new system for calibrating its flow meters referred to as a Transfer Standard Method (TSM) liquid calibration system. The transfer standards for this system are Coriolis reference meters installed in parallel. The stability of the reference meters is one of the largest contributors to the overall measurement uncertainty in this system. To reduce the measurement uncertainty, reference meters are limited in flow range and two reference meters of each size are used as a quality check with one installed upstream of the unit under test (UUT) and the other installed downstream of the UUT. An updated design of the Transfer Standard Method liquid calibration system incorporating reference meters in series was recently built and put into service at Micro Motion. A discussion of the updated design, the quality check data that is inherently built into the updated design and an analysis of these results are presented in this paper.

Manufacturers of large-scale hydraulic machines face high liquidated damages if they can not meet performance guarantees due to contractual stipulations. Accurate determination of efficiency, power and flow is therefore of major interest. For plants exceeding heads of 100 m, the thermodynamic method represents the standard method. We present a mathematical refinement that uses additional power measurements to yield an analytical solution of the flow. Under favourable conditions, the measurement uncertainty is lower compared to that of other absolute flow measuring methods. With higher heads an even lower uncertainty can be expected.

This papers presents the results obtained in a research inter-comparison organized in the framework of the development of traceable micro flow facilities for liquids within the EMRP project "HLT07 Metrology for Drug Delivery". The paper presents the protocol of the comparison and the first results revealing some discrepancies between the laboratories.