Showing papers on "Thermal mass flow meter published in 1983"

Parallel path Coriolis mass flow rate meter

Abstract: A flow meter apparatus for measuring the mass flow rates of fluids passed through two essentially parallel, cantilever mounted U-shaped flow tubes where, instead of the fluid serially passing through one of the U-shaped flow tubes and then through the second U-shaped flow tube, the fluid is essentially evenly divided and half of the fluid is passed through one U-shaped flow tube and the other half of the fluid is passed through the other U-shaped flow tube. The two U-shaped flow tubes are sinusoidally driven as the tines of a tuning fork, and when a fluid is passed through the oscillating U-shaped flow tubes Coriolis forces are generated which torsionally deflect the U-shaped flow tubes. Such torsional deflections are a function of the mass flow rate of the fluid passing through the two U-shaped flow tubes.

Thermal mass flow meter

Abstract: The flow meter (10), particularly useful in monitoring flow in semiconductor manufacturing operations, measures mass flow rate of fluids and is fabricated by providing spaced webs (16) deposited on a silicon substrate (11) and fluid flow grooves (13) etched across a substrate surface and extending under the spaced webs. The webs 16 include a low thermal conductivity layer deposited in spaced aligned portions of the substrate and electrically resistive pathways deposited on the layer portions (61). The webs act as temperature sensors and/or heaters. Heat is added to the flowing fluid and a differential temperature is measured on a bridge circuit as is known in the art to measure flow rate. A cover (12) has etched grooves (14a) which match the grooves (13) of the substrate to form a fluid passageway in which the web bisects the passageway forming an "air-foil" like bridging member extending completely across (or cantilevered across) in transverse relation to the flat sides of the substrate on either side of the groove. Normally multiple series of webs and multiple grooves are employed to provide redundancy of the flow meter channels in the event contaminants plug a particular channel.

Thermal mass flow meter

Abstract: The disclosed thermal mass flow meter has a heat conductive case having a fine groove and a sensor pipe disposed in said fine groove so as to carry fluid flow to be measured.

Miniature thermal fluid flow sensors and batch methods of making same

Abstract: Miniature thermal fluid flow sensors of the airfoil type are made in batch form by forming the thermal fluid flow sensors on a thin sheet of material and bonding the sheet over an array of duct structures and dicing the individual sensors and duct structures apart In another embodiment, thin carrier sheet portions of a wafer bearing the thermal fluid flow sensors of the airfoil or grid type are supported by surrounding frame portions of the wafer The wafer is diced to separate the individual sensing chips The respective chips are mounted across respective fluid flow ducts For the airfoil type sensor, portions of the frame are broken away for undisturbed flow over the thin carrier and sensor In one thermal flow sensor configuration, a flow heater is disposed in between first and second thermal flow sensors in heat exchanging relation therewith A third thermal flow sensor is disposed upstream of the others out of heat exchanging relation with the heater for operation of the heater at a certain temperature above that sensed by the third sensor In the low flow regime, flow is measured by the difference between the outputs of the first and second sensors, whereas in the high flow regime, the power required to maintain the temperature of the heater serves as a measure of the flow

Apparatus and method for monitoring a plurality of flow meters

Abstract: A microprocessor controlled apparatus monitors a plurality of flow meters for computing and displaying the flow rates detected by each flow meter, the total volumes accumulated through each flow meter, the sum of the current flow rates for the flow meters, and the sum of the total volumes for the flow meters. The information from which the computations are made and the system operating parameters are transferred to a non-volatile memory in response to electronic means for detecting when a power outage or interruption occurs.

Flow meter for a two-phase fluid

Abstract: A mass flow rate measuring apparatus includes a pair of velocity detecting electrodes spaced by a portion of a wider density detection electrode so as to eliminate any mutual interference between the velocity detecting electrodes. A temperature compensation circuit is used to compensate for errors in the density measurement otherwise caused by the temperature characteristic of the flow pipe and the carrier medium.

Fluid sampler and gas flow control system and method

Abstract: The fluid Sampler is used to sample gases in a collecting device and includes a flow control valve having a manually adjustable flow restricting orifice and a vacuum pump for drawing gas from the atmosphere through the collecting device and flow control valve to form therethrough a primary flow path. A flow controller is used to supply a supplemental flow of gas taken from the discharge end of the vacuum pump and supplied to the suction end of the vacuum pump in response to the differential in pressure across the flow control valve. The supplementary flow rate is automatically adjusted to maintain the differential in pressure constant.

Flow rate meter

Abstract: In flow rate meters with a ceramic substrate extending into a flow opening and having at least one temperature-dependent resistor film, there is the danger that excessive acceleration forces from a fall or from an impact will break the ceramic substrate. There is also the danger of destruction of the ceramic substrate from being unintentionally touched by an object or a finger. To increase the protection of the ceramic substrate against breakage, a reinforcing element is provided on a first housing half, protruding into the flow opening over a portion of the ceramic substrate and being glued to the ceramic substrate in the same manner as the first housing half. Protective ribs protrude from the housing halves into the flow opening in the direction of the ceramic substrate and prevent unintentional contact with the ceramic substract by objects or fingers. The flow rate meter is suitable for measuring the flow rate of the aspirated air in internal combustion engines.

Mass flow meter

Abstract: When a fluid, gas or compressible liquid, is to be used, e.g. as a fuel, it is better to meter the rate of flow of mass, not volume. If the flow is not laminar and particularly if a hydrodynamic oscillator is used, two sensors (7,9), or one differential sensor, can show the frequency of cyclic pressure variations and the amplitude of the differences between the sensors. These give directly, amplitude = K1 x density x (velocity) frequency = K2 x velocity so the rate of mass flow may be determined. Examples are given of a COANDA meter on which the measurements may be made, and of computing circuits by which the data may be converted to mass flow rates.

Measuring device in an internal combustion engine

Abstract: A measuring device in an internal combustion engine is proposed for the flow rate, related to a stroke, with a flap-type flow meter whose flap deflection determines the position of a potentiometer (15), the supply voltage of the potentiometer being dependent on the speed of rotation. In this way, an output signal of the flow meter is obtained which is inversely proportional to the stroke-related flow and the flow meter is suitable both for detecting the load of the internal combustion engine and, in conjunction with the measurement, the rate of exhaust gas feedback.