Showing papers on "Thermal mass flow meter published in 1978"

Digital fluid flow rate controller

Abstract: A precision digital flow rate control system particularly suitable for controlling the flow of an inert gas into the atomizing furnace of an atomic absorption spectrometer. The selection of the desired flow rate is made by switching the flow through one or more of the plurality of tubes having restrictors that limit the flow according to digital steps. The flow is switched by directional control solenoid valves that direct the flow either through a flow restrictor to the atomizing furnace or through an identical flow restriction to a vent. Therefore, there will always be a constant flow through each valve and, since the inlet pressure regulator will always see a constant load, it can maintain a very constant pressure to the valves.

Method and apparatus for measuring particulate matter flow rate

Abstract: A flow rate meter is provided for measuring the flow rate of particulate material being conveyed in a fluid stream along a tubular member. The apparatus includes a throat portion in the tubular member which has a length sufficient to accomplish a pressure drop adequate for accurate particulate material flow rate measurement in the conveying of particulate material in a fluid stream through the throat. The pressure drop is measured across the throat and the measured pressure drop is correlated with the particulate material flow rate. There can be provided converging and diverging tubular sections on opposite sides of the throat to form a venturi. One or more of the flow rate meters can be used in the control of a particulate material blending system. A fluid flow rate measuring means can be used in conjunction with the flow rate meter to provide a signal representative of the difference between the flow rate of particulate material and fluid and the flow rate of the fluid alone, i.e., the flow rate of particulate material alone.

Apparatus for metering fluid flow

Abstract: Fluid flow metering and control apparatus includes a positive displacement flow meter, a pressure sensor responsive to the pressure difference between the inlet and the outlet of the flow meter and a servo drive mechanism controlled by the pressure difference sensor to maintain the pressure difference between the inlet and outlet side of the flow meter at zero. A hydraulic motor is utilized as the servo drive means.

Fluid flow measuring apparatus

Abstract: A fluid flow meter, for example for measuring the velocity of an air flow, comprises a flow duct having a transverse vortex-shedding bar, the ultrasonic or other detector means for sensing the shedding of Karman vortices from the bar as the fluid flow passes the bar, and for converting the alternating output signal of the detector means into a signal of square-wave form of operating a digital counter, and one or more additional cross-members extending across the flow duct downstream of the flow section where the vortex-sensing means operates, the additional cross-member extending transversely to the vortex-shedding bar and being of cylindrical or aerofoil cross-section, or of rectangular or other cross-section having a flat upstream face parallel to the bar. The provision of the additional cross-member is found to improve the regularity of the vortex-shedding from the bar and hence the accuracy of the meter reading.

Testing and inspecting device of flow meter

Abstract: PURPOSE: To accomplish the test and calibration in a simple but highly accurate manner by arranging a normal flow meter and a sonic nozzle upstream and downstream of a passage, respectively, thereby to eliminate the deteriorating influence upon the flow rate measurements. CONSTITUTION: Atomospheric air or other gases are compressed by a compressor 5, and a storage tank 6, which can be held at a necessary pressure, is charged with the compressed air or other gases through a suitable filter 4 for filtering dusts, mists and the like. The resultant fluid is discharged under a sonic condition into the atmosphere from a downstream standard sonic nozzle or a sonic nozzle 3 to be tested through a flow meter to be tested or a standard flow meter 2, which is arranged at a downstream position. Incidentally, the sample may be either the flow meter 2 or the sonic nozzle 3, and the standard element in that case is calibrated in advance by another method. As a result, the disturbing phenomena or other deteriorating influences due to the provision of the sonic nozzle upstream of the flow meter are eliminated so that the testing and calibrating operations can be accomplished in an easy but highly accurate manner. COPYRIGHT: (C)1980,JPO&Japio

Fuel supply apparatus

Abstract: A fuel supply apparatus is proposed which serves to control a mixture-compressing, externally ignited internal combustion engine. The fuel supply apparatus includes at least one fuel depositing point in the air intake manifold, within which an air flow rate meter and an arbitrarily actuatable throttle valve are disposed in series and the air flow rate meter is moved against a restoring force in accordance with the air quantity flowing therethrough. The air flow rate meter, which is embodied as a flat rotary element in the shape of a circular sector, more or less widely opens an aperture which defines the cross-sectional width of the air intake manifold and is rotatably fixed about a rigid shaft extending in the direction of air flow. The intake manifold pressure upstream of the air flow rate meter acts on one side of the air flow rate meter, and the intake manifold pressure downstream of the air flow rate meter acts on the other side of the air flow rate meter. In a plane downstream of the air flow rate meter which is parallel to the aperture, there is an arbitrarily actuatable lobed element, by means of which the flow-through cross-sectional area at the aperture can be varied in accordance with the operating characteristics of the internal combustion engine.

Measurement of flow angle and mass flow rate in an unknown flow field using hot film and hot wire probes

Abstract: A data reduction technique applicable to constant temperature hot film and hot wire probes is presented which is used to determine flow angle and mass flow rate in an unknown flow field over a wide range of flow conditions at supersonic and hypersonic velocities. The technique virtually eliminates the effect of Reynolds number on a probe's flow angle sensitivity. Methods for extrapolating a limited amount of mass flow rate calibration data to include the range of mass flow rate encountered in an experiment are also given. This technique has been applied to data obtained using a hot film probe during surveys in the leeside flow field of a space shuttle orbiter configuration.

Locating the producing layers in HGP-A

Abstract: The characteristics of the Hawaii Geothermal Project well HGP-A were presented last year in terms of flow rates under throttled conditions, downhole pressure and temperature profiles, and pressure drawdown and buildup tests. In particular, the more recent pressure buildup analyses have indicated the possibility of multiple production zones. In an attempt to locate these production zones, two tests have been conducted during the past six months. A direct means of determining the locations of the permeable layers is to measure the flow rates at the suspected depths. However, two difficulties immediately arise. Since the flow in HGP-A is a mixture of saturated liquid and vapor, the mass flow rate cannot be measured using a conventional spinner (which is a volumetric flow meter). Furthermore, the temperature encountered in the wellbore exceed the temperature limits of that instrument. To circumvent both of these difficulties, the well was allowed to produce only under severely throttled conditions. This had the effect of keeping the well fluid in a liquid state at temperatures well within the capability of the flow meter. The flow meter setup used for the production and pumpdown tests is shown in Figure 1.

Measuring mass flow by means of a heat flowmeter

Abstract: 1. Existing simplified methods of designing thermal flowmeters do not satisfy the requirements of the developers and designers of these instruments, which raises the need to create methods of calculation based on solutions to the heat-transfer problem in its most general statement. 2. Heat flowmeters are, in fact, thermoanemometers, the readings of a noncontact type of heat flowmeter corresponding to the average rate of flow while the contact types of instrument read the local rate of flow. 3. The indication of a thermoanemometer corresponds to the mass rate of flow when laminar flows of any liquid are being measured and turbulent flows in liquid metals; in all other cases, its indications correspond to linear rates of flow, apart from the calorimetric thermoanemometer with a heated or cooled flow of any cross-sectional area, which always indicates mass rates of flow.