Thermal mass flow meter

About: Thermal mass flow meter is a research topic. Over the lifetime, 1759 publications have been published within this topic receiving 21878 citations.

Compound flow meter and leak detector system with a valve that is shut under abnormal flow conditions

Abstract: An electronic liquid flow-measuring system comprising of a power source; a main electronic flow meter and a secondary liquid low flow electronic meter connected as a by-pass to said main meter; a microprocessor or for controlling flow measurements and the three position valve; a three position valve connected to both meters for closing said electronic main flowmeter at very low flows permitting only said secondary liquid flow meter to operate at low flows, such that at normal flows the valve is in its second position allowing the liquid to flow through both meters, and when the liquid flow is beyond a predetermined flow the valve is in its third position blocking all flow, and wherein said third position is achieved by means for opening a gate that permits the moving part of the valve to reach its third position and digital and analog processing means for producing readable numeric output values.

Liquid flow sensor for nano‐ and micro‐flow ranges

Abstract: Purpose – To present a new generation of liquid flow sensors that is capable of meeting the requirements as imposed by the life science, analysis, biotech and other marketsDesign/methodology/approach – A description of the design and development of low flow rate measuring system and typical applicationsFindings – The system described uses tubes made of silica, stainless steel or PEEK, and either constant power or constant temperature methods in conjunction with a heater and temperature sensor The tested instruments were capable of measuring flow ranges between 25‐500 nl/min (smallest flow range) and 100‐2000 μl/min (largest flow range) water, with operating pressures up to 100 bar (up to 400 bar for flow meters with flow ranges below 100 μl/min)Originality/value – Presents information on a new generation of liquid flow sensors

Flow sensor and mass flow controller using the same

Abstract: A low cost, compact, high performance flow sensor that can be made small in size even for use in a large flow rate and a mass flow controller using the same are provided. The flow sensor includes a bypass passage, a sensor passage, and a bridge circuit including heat-generating resistance wires that constitute a part of the bridge circuit and are wound around the sensor passage. The flow sensor determines a total flow rate of a fluid that flows in a branched manner through the bypass passage and the sensor passage at a predetermined flow ratio. The total flow rate is determined by detecting, as an unbalance of the bridge circuit, heat transfer caused by the fluid flowing through the sensor passage and is outputted as a sensor output of the flow sensor. In the flow sensor, the bypass passage includes a plurality of fine flow passages each having a cross-section defined by a substantially linear edge and a curve in contact with the substantially linear edge. The ratio of the equivalent hydraulic diameter (d) of the fine flow passages to the common logarithm of the length (T) of the fine flow passages is 0.27 or less. The flow sensor is installed in the mass flow controller.