Digital mass flow control

MOVPE has become the main industrial technology for the preparation of modern electronic (HEMTs for mobile communication, navigation and location) as well as optoelectronic (lasers, LEDs, detectors or solar cells). Now a new generation of digital mass flow controllers is described, claimed as ideally suitable for fast, accurate and stable precursor supply into an MOVPE reactor. The instruments are capable of handling typical precursor flow rates of the order of (gases) 5 slm AsH3, PH3 and NH3 and (liquids) 50 g/h TMA, TMG and TMI. The settling time t98% of the instruments is 200μs and 2μs, respectively

Micro Coriolis mass flow sensor for chemical micropropulsion systems

We have designed a micromachined micro Coriolis flow sensor for the measurement of hydrazine (N2H4, High Purity Grade) propellant flow in micro chemical propulsion systems [1]. The sensor measures mass flow up to 6 mg/s for a single thruster or up to 24 mg/s for four thrusters. The sensor will first be used for measurement and characterization of the micro thruster system in a simulated space vacuum environment. Integration of the sensor chip within the micro thruster flight hardware will be considered at a later stage. The new chip has an increased flow range because of an integrated on-chip bypass channel

Water flow calibration facility in France (1 ml/h to 10 000 ml/h)

Through the world, the tendency to miniaturize all objects is spread widely. Concerning liquid flow metering, several manufacturers are already industrializing instruments specific for small flows. On a metrological point of view, few National Metrological Institutes (NMI) are able to calibrate flowmeters with liquid at flow rate smaller than 1 l.h-1 (2,8.10-7 m3.s-1). During the last five years, LNECETIAT (French NMI) was on progress to design and build a new calibration facility to ensure traceability to the international system of units. This paper will present the concepts and the first results obtained during the validation stage of this new standard

Towards system-level modeling and characterization of components for intravenous therapy

Problems occur regularly with intravenous therapy, especially with the flow behavior. A mechanical model can predict which components of intravenous therapy systems introduce non-ideal effects in the flow. This study concentrates on gaining quantitative information of each separate component for intravenous therapy, characterize its non-ideal effects and combine these quantities in one system-level model. The model will help in the development of a mass flow sensor which can be used in a control system for intravenous therapy

Micro Coriolis mass flow censor with extended range for a monopropellant micro propulsion system

We have designed and realised a micromachined micro Coriolis flow sensor for the measurement of hydrazine (N2H4, High Purity Grade) propellant flow in micro chemical propulsion systems. The sensor should be able to measure mass flow up to 6 mg/s for a single thruster or up to 24 mg/s for four thrusters. The sensor will first be used for measurement and characterisation of the micro thruster system in a simulated space vacuum environment. Integration of the sensor chip within the micro thruster flight hardware will be considered at a later stage. The new chip has an increased flow range because of an integrated on-chip bypass channel. First measurement results have demonstrated an increase in flow range which corresponds well to the designed bypass ratio

A compact micro Coriolis mass flow sensor with flow bypass for a monopropellant micro propulsion system

We have designed, fabricated and tested a micromachined Coriolis flow sensor for the measurement of hydrazine (N2H4) propellant flow in a micro chemical propulsion system (uCPS). The sensor will be used for measurement and characterization of the uCPS in a simulated space vacuum environment. To reach the required flow range a bypass system is integrated. Initial measurements demonstrate an increase of the flow range in accordance with the designed bypass ratio. The sensor is operated as a two-port resonator in an oscillator circuit to improve frequency stability