DE2453765A1 - MEDIUM FLOW DEVICE, METHOD OF MEASURING MEDIUM FLOW RATE BY SUCH DEVICE, AND SYSTEM FOR MEASURING MEDIUM FLOW RATE WITH DEVICE OF SUCH KIND - Google Patents

Description

7 / .TElITANWALIoBUnO
D-4 DÜSSELDORF. SCHUMANNSTR. 97

PATENT LAWYERS:
Dipl.-Ing. W. COHAUSZ Dipl.-Ing. W. FLORACK ■ Dipl.-Ing. R. KNAUF Dr.-Ing., Dipl.-Wirtsch.-Ing. A. GERBER Dipl.-Ing. HB COHAUSZ

^r ihe Lucas Electrical Company Limited

'Well Street

GB-Birmingham '12th November 1974

Medium flow device, method for measuring the medium flow rate through, such an apparatus and system for measuring the medium flow rate with an apparatus of this type

The invention relates to a hedium flow device with a we- ' belkainmer, into the media through an inlet channel on the periphery the chamber and in which the medium flows through the chamber, an outlet channel leaves, wherein the outlet channel is arranged so that a continued vortex movement of the medium is enabled, as well as a A method and system for measuring mediureal flow rate with an apparatus of this type.

In one aspect of the invention, a device of the type mentioned characterized by an ultrasonic transducer and an associated receiver, which is arranged with respect to the outlet channel so that ultrasonic vibrations forward transmitter can be directed across the channel to the receiver, in such a way that transmitted vibrations through Disturbances are modified in the vortex movement of the medium occur in such a way that a correspondingly modified receiver output is produced.

The encoder and the receiver are usually diametrically opposed to each other Locations arranged opposite the channel, the locations preferably being on the periphery of the channel.

The transmitter and the receiver are preferably on the outer wall of the channel arranged, and expediently they sit at the mouth of the channel. The receiver is expediently a converter which is an electrical one Signal generated that forms the modified output.

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It has been found that distance distances in vortex motion generally corresponding to the rate of medium flow through the device occur, so that a signal modified by such distances generally changes as a puncture of the mediural flow.

Accordingly, according to another aspect, the invention consists in one A method of measuring the rate of medium flow through a device of the type mentioned, which is characterized in that ultrasonic vibrations are sent transversely to the medium flow, the vibrations are received after passage through the flow and modifications imposed on the vibrations are detected by distances that as a consequence dee: medium flow rate occur.

The invention is explained in more detail below with reference to the drawings. In the drawings are:

Fig. 1 is a schematic plan view of a device according to a Embodiment of the invention,

Fig. 2 is a side view, partially in section, the I'ig. 1 shown device,

Fig. 3 ^a Tind ~ $ b, 4 "5 ¹¹ ^ d 6 playback of combinations of the resulting at the transmitter and at the receiver of the apparatus shown in Fig. 1 waveforms during various operating conditions of the apparatus,

FIGS. 7 to 12 show the reproduction of data on the receiver only on the one shown in FIG. The device shown in FIG. 1 results in waveforms when the device is used to monitor the air flow rate in an internal combustion engine under various operating conditions of the engine, and

Fig. 13 is an illustration of a circuit diagram of a phase detector circuit to generate an output as a reproduction of the phase relationship between the transmitted and received vibrations, which can be generated by the device shown in FIG.

The device shown in Figs. 1 and 2 is generally used as a vortex

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whistle "known and has a cylindrical vortex chamber 21 circular Cross-section, which has eight medium inlets 22 on its periphery, which extend tangentially to the chamber. Axially from one end the chamber 21 extends a medium outlet pipe 2J, and 2J, respectively diametrically opposite points at the mouth of the outlet tube sit an ultrasonic transmitter and a receiver 24 "or 25, expediently in the form of electromechanical transducers so that ultrasonic vibrations can be sent across the medium flow in the output tube for reception by the receiver.

In operation, the device sits in connection with the outlet tube 23 with a source of a pressure medium under a pressure which the medium inlets 22 are exposed so that a flow of air is directed through the inlets 22, which because of their tangential locations of the exit tube compared to a vortex in the air flow within the tube 23 permit. Ultrasonic vibrations are sent from the transducer 24 across the medium flow at the mouth of the outlet tube, and in the medium flow resulting distances, which are generally dependent on the rate of medium flow, as has been shown, modify the transmitted ones Vibrations in a manner that depends on the flow rate. The modified vibrations that are received by the receiver 25 create a correspondingly modified receiver output in the form of an electrical signal which changes according to the flow rate. Such a signal can be used to generate a continuous indication the flow rate through the device is used for monitoring purposes and / or e's may possibly after suitable reinforcement can be used to operate means for performing a function which depends on the air flow rate. Such means can for example be one or more fuel injectors for a fuel injector in an internal combustion engine, and in this case is the outlet tube 25 conveniently with the air inlet manifold and the tubes 22 are connected to the air filter.

While in the embodiment in question, which is shown, eight meters

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Medium inlets 22 are shown, it is understood that any Number can be used, the number and the orifice size depending on the size of the medium flow that is being used. While Furthermore, in the illustrated embodiment, the medium outlet tube 23 has been connected to a pressure source whose pressure is below the is, with which the medium inlets 22 are acted upon, the works Apparatus just as well with a source of positive pressure fed to the medium inlet 22, while the outlet tube 23 with the atmosphere connected is.

A monitoring of the medium flow rate by the one described above The device is expediently achieved in that electrical Signals that reproduce the transmitted and received vibrations are fed to a suitable electronic display device, such that, for example, for the Pail of a cathode ray oscillioscope the vibrations on the screen of the oscilloscope are reproduced on appropriate tracks. The lanes are set up to be accurate have the opposite phase than that in Pig. Yes is shown and they will then superimposed. Thus, when there is no medium flow through the device, the paths are identical and they cancel each other out away to create the straight path that is used in Pig. Jb is shown. With at the beginning of the medium flow, the combined path takes one shape in which it reproduces a modulated version of the transmitted vibration waveform. The modulation envelope provides both the phase and also represents the amplitude modulation in the received waveform, and at low flow rates the envelope has that in Pig. 4 shown Porm. With as the flow rate increases, the modulation in the in Pig. 5 and 6 shown porm to, and since the modulation essentially as a puncture occurs when the flow rate through the device occurs, the waveform generated is a useful indication of the flow rate. A deterioration in the porm of the casing occurs with increasing flow rate, which shows Pig. 6 can be seen, however a suitable filter circuit can be used to improve this.

Alternatively, the medium flow rate through the device can thereby

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be monitored that the received signal is observed alone, since it is itself an amplitude modulated version of the transmitted vibration waveform. For example, show Pig. 7 to 12 the waveforms generated at the receiver during various operating conditions arise which occur when the device is used for this purpose will monitor the air flow rate to an internal combustion engine. Fig. 7 shows the waveform obtained when the engine is idling, while the waveforms in Pig. 8 and 9 for lighter or average Engine load arise. When the engine is running at high speed, the waveform shown in Fig. 10 appears, while when the engine is is accelerated at medium and high speeds, the waveforms according to Fig. 11 and 12 arise »

Instead of, or in parallel with, a pictorial representation of the waveforms to provide a visual display as described above, they can be done electronically using conventional methods are counted and as a digital output for display, the medium dur chfl-u & a te reproduced by the device.

In addition, the flow rate through the apparatus described above can be monitored by a detector which produces an output which is determined by the phase relationship between the transmitted and received vibrations. The output then depends on the medium flow rate, since it has been determined that the vortex movement in the outlet tube 23 creates a low pressure zone which advances around the tube and causes a change in phase of the vibration received from the vibration transmitted each time an interruption occurs of the ultrasonic beam takes place. A circuit diagram of a suitable detector is in Pig. 1J shown. There , the transmitter 24 and the receiver 25 are transducers which generate electrical signals which reproduce the transmitted and received ultrasonic vibrations. As shown in Pig. I3, the signal at the receiver 25 has bias voltages that are applied to it, which go through the resistors R ^ t Sg ι R ₇ and R_, with a connection to a direct current source (not shown) via a positive or negative power line 3I or 32 is made. Diodes

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D ₁ and D ₂ limit the magnitude of the alternating current component of the received signal, and this is _{fed to the respective control electrodes of transistors T 1 and T 5} which, when conducting, are supplied with a constant collector / emission electrode current from the current mirror circuit which is passed through resistors R. ₁ , Hp, R, and R and the transistors T ₁ , T ₂ and T is formed. The transistors T ₄ , Tc form a differential amplifier for the received signal, and as can be seen, the alternating current component in the signal switches the transistors T, T ₁ . alternatively during the respective half-periods.

Correspondingly, the signal at converter 24 receives a bias voltage from resistor R _Qf and its alternating current component is supplied by diodes D? » Sj clipped. Furthermore, the sent signal is fed to the control electrodes of two pairs of transistors T, -, Tg or T ₇ , T _Q in order to control their conduction. Each pair of transistors forms a differential amplifier and the arrangement is such that the transmitted signal _{turns on transistors T / -, T q} during one half cycle and turns on transistors T, T _Q during the other half cycle.

During operation, an output is taken from two connections 35 »34, connection 33 being connected to the collectors of transistors Tg, T ₈ and connection 34 being connected to the collectors of transistors T ₇ , Tq. If the transmitted and received signals are in phase, the transistors T., Tg and T9 are switched on in a half cycle of each signal, so that current only flows in the circuit formed by the resistor R ₁₀ and the transistors Tg, T. so that terminal 33 is negative with respect to terminal 34. In / other half-cycles, the transistors T ₁ -, T ₇ and T _{Q are} switched on, and current now flows through R ₁₀ , Tq, T ₁ -J so that the terminal 33 remains negative with respect to the terminal 34. Transistors T _7, T switched _8, so that current flows in the circuit through the resistor R ₁ and the - if the sent and received signals are 180 ° out of phase but which are when the transistor Έλ is eingeschaltetr, Transistors T ₇ , T, is formed. In this phase, the terminal 34 is negative with respect to the terminal 33. In the next half cycle, the transistors T ₁ -, Tg and T _{Q are} switched on, so that current

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still flowing through E ... ... and terminal 34 still negative is than port 33

The output from the circuit described above is thus such that terminal 35 is negative with respect to terminal 34 whenever the transmitted and received signals are in phase,
while terminal 34 "is negative with respect to terminal 33 when the signals are 180 out of phase, with a zero output being obtained if the signals are 90 out of phase. The frequency of the output can then be used to provide a measure of The rate of fluid flow through the device can be used, with a capacitor C1 preferably connected to terminals 35-34 to smooth the output.

Expectations

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Claims (12)

Expectations 1. Medium flow device with a vortex chamber into the medium flows through an inlet channel at the periphery of the chamber and when the medium leaves the chamber through an outlet channel, the outlet channel is arranged to allow continued vortex motion of the medium, indicated by a Ultrasonic transmitter and an associated receiver which is arranged with respect to the outlet channel so that ultrasonic vibrations from the transmitter via can be directed across the channel towards the receiver in such a way that transmitted vibrations are modified by ice turbances shown in the vortex movement of the medium occur in such a way that a correspondingly modified receiver output is generated. 2. Device according to claim 1, characterized in that that the transmitter and the receiver are arranged opposite the channel at diametrically opposite locations. 5 device according to claim 2, characterized in that that the points are on the periphery of the outlet channel. 4. Device according to one of claims 1 to 3, characterized in that that the transmitter and the receiver sit on the outer wall of the outlet channel. 5 · Device according to one of claims 1 to 4 »characterized in that that the transmitter and the receiver sit at the mouth of the outlet channel. 6. Device according to one of claims 1 to 5, characterized in that that the receiver is a transducer that generates an electrical signal that forms the modified output. 7 · Method of measuring medium flow rate through a device according to one of claims 1 to 6, characterized in that that ultrasonic vibrations are sent across the medium flow the vibrations after the passage across the passage 509832/0661 flow are received and modifications are found that affect the Vibrations can be imposed by distances which occur as a function of the medium flow rate. 8. The method according to claim 7 »characterized in that that the modifications were detected by monitoring the waveforms obtained by combining the transmitted and received vibrations. 9 · The method according to claim 7 »characterized in that that the modifications are made by monitoring the vibrations received can be determined alone. 10. The method according to claim 7 »characterized in that the modifications by monitoring changes in the Phase of the vibrations received versus the vibrations sent, caused by the distances to be 'ascertained'. 11. System for measuring medium flow rate with one device according to one of claims 1 to 6, which is located in the flow path of the medium, characterized by means for determining modifications, which are imposed on the vibrations which are directed transversely to the outlet channel, caused by the Disturbanzen that as a consequence the vortex movement of the medium in the outlet channel. 12. System according to Claim 11, characterized in that that the means monitor a combination of the transmitted and received vibrations. 13 system according to claim 11, characterized in that that the means alone oversee the vibrations received. 14 system according to claim 11, characterized in that that the means monitor phase changes in the received vibrations with respect to the transmitted vibrations. 509832/0661