GB2310285A

GB2310285A - Flowmeter

Info

Publication number: GB2310285A
Application number: GB9602885A
Authority: GB
Inventors: Mansanori Amemori; Toshiyuki Hasegawa; Takeshi Miyamoto; Shinya Nozaki; Takashi Kobayashi
Original assignee: Zexel Corp
Current assignee: Bosch Corp
Priority date: 1995-01-26
Filing date: 1996-02-13
Publication date: 1997-08-20
Also published as: JPH08201129A; DE19605285C1; GB9602885D0

Description

1 1 1 2 1 1 3 4 6 7 13 14 is 16 17 1B 21 22 23 24 25 FLOWMETER 2310285 1

BACKGROUND OF THE INVENTION 1 Field of the Invent.inn.

The present invention relates to a flowmeter for measurins the flow rate of fluids, and in particular to a flowmeter for obtaining a flow rate by detecting the rotation speed of impellers caused to rotate by fluid. 1 Description of the Related Art.

There are generally several types of flowmeters for detecting the flow rate of fluids, for example. a type that detects the calorie taken away from by movements of the fluid, and a type that detects mechanical movements activated by a force which the fluid has, However. either type has a shortcoming such as a large error being Produced in the detected flow rate or some influences being given to the flow of the fluid by the 1 detection itself which is a resistance to the flow of 1 the fluid, e te.

An impeller type flowmeter represented by a waterway flowmeter. has such a mechanism that a flow channel lb of fluid is produced in the 1 direction of the arrow A-A which is the tangential 1 direction of an impeller la, wherein the impeller la is 1 devised to rotate due to fluid force which the fluid has 1 when the flow exceeds a certain flow rate, and rotationshown in Fig.1, e te.

1 1 BAD OFUGINAL 0 j 6 7 1 1 12 13 14 is 16 17 21 22 23 1 24 1 25 1 1 of the impeller la is detected man (not illustrated) in the vicinit,,. of imPelier la which will be the rotation center, ard is transmitted to an instrumental panel where the flow rate 1 of the fluid is displayed.

Furthermore, although the fue ty must be accurately controlled in a injection quantity has conventionally 1 indirectly by calculating the fuel in from the number of ensine, rotations a detecting the control rack position o Injection pump or detecting the contr 1 of a distributor type fuel injection pump.

There are some problems such as wearing and y bY a gear the axis lc of tht> injection quantidiesel engine. the been grasped ection quantity that time through an in-line fuel 1 sleeve position backlashes in a gear mechanism. It was difficult to make an impeller type flowmeter very small and to accurately detect the flow rate of high speed fluids due to a 1 complicatedness of a mechanism consisting of mechanical elements.

Furthermore, in a fuel injection pump of a diesel engine, it was difficult to accurately detect the fuel injection quantity as the injection quantity may change due to unevenness of the quality such as machining accuracy, assembling accuracy. etc.. and chronological changes thereof.

2 BAD. ORIGINAL A 3 1 t y p c 4 es due 6 1 h igh 1 7 1 r 0 t 9 1 o f 1 speed 12 1 t ion 13 1 14 1 spee f low 17 1 f I ow r ter i s t 1 r a t e 1 21 1 t ion 22 23 1 i 24 1 p r c s 1 1 sma 1 1 SUMMARY OF-THE INVENTION

The present invention aims at making an impeller flowmeter very small so as not to receive influenrto wearing and backlashes of gears The i n v e n tion aims at detecting the flow rate of speed fluids The invention tion speed of an non-steady flows.

The invention aims at detecting the rotation even though the Impeller rotates in either direcdepending on the flow direction.

The invention aims at detecting the of an impeller and at the same time d direction of fluid.

The invention aims at accurately detecting the ate so as not to influence the injection characics of fuel.

The invention aims at detecting the injection which is a non-steady flow in the period of injecby improving the response for the flow rate changaims at detecting an instantaneous impeller and to ensure the metering rotation tecting the The invention aims at matching high injection sure by making the pressure receiving surface 3 BAD ORIGINAL 0 4) 1 1 1 2 1 1 8 9 1 1 12 1 13 1 1 1 5 1 19 The invention aims at making the inertia force small by reducing the turbine mass. whereby the flowmetr is made very durabic against external impacts.

The invention aims at making the interval bet- tting elements and light receiving elelow output light emitting elements and y light receiving elements are able to be used to decrease the production cost.

The invention aims at causing a flowmeter not to be influenced by electromagne detecting the number of revol It is therefore an ob provide a flowmeter to grasp detecting the rotation speed a flow channel flowmeter comprises a transmi transmitting a laser beam or end of the impeller which is means for receiving the lase which is reflected from the impeller and a data processing means for obtaining. through calculacions. the difference between the frequency which is captured by the receiving means and the frequency transmitted by the transmitting means and for detecting the rotation speed of the impeller based on the value obtained.

1 ments, whereby 1 1 low sens it i v! t !en light emi tic noises, etc, when utions of a tu rb ine. ject of the invention to a flow rate of a fluid by of an impeller disposed in of fluid to be metered. wherein the tting means for ultrasonic wave in revolution, a receiving r beam or ultrasonic wave to the tip 4 BAD ORIGINAL 03 1 2 3 4 6 7 9 1 1 10 1 12 1 13 14 Is 16 1 7 18 19 21 22 23 24 0 -0- 0 a 6 0 04 c.

1 1 1 With the inventlon, a laser beam or ultrasonic wave is transmitted to the tip end of an impeller whic 1 is disposed in a flow channel of the fluid to be mete i and is revolving. and the laser or ul i 1 reflected by the impeller is captured by the mean the the impe s. whereby the difference between the fr caPtured signals i trasonic wave r e c e i v i n g equency of s calculated and the frequency of transmitted signals. and the rotation speed of the ller is able to be detected by the obtained value. BRIEF DESCRIPT(ON OF DRAWINGS Fig.1 is a view showing the construction of a onventional impeller type flowmeter.

Fig.2 is a view showing the components in a 1 circular tube of a flowmeter according to a first preferred embodiment of the invention.

F i g i m p e 1 e r i n F 1 g r c u 1 a r r eA is an enlarged view of the vicinity of the he construction shown in Fig.2.

is a view showing the components outside the c tube of a flowmeter according to the first preferred embodiment of the invention.

Fig.5 is a view showing the construction of a flowm,-ter according the inven t ion.

F ig. 6 i s the used in a f 1 owme te r to a second Preferred embodiment of front elevational view of a turbine according to a third preferred 6AD ORIGINAL J0 embodiment of the invention 2 1 3 4 1 1 turbine in the circular tube of a flowineter according to 6 1 the third preferred embodiment of the invention.

7 1 Fig.9 is a view showing the construction of a 8 1 flowmeter according to the third preferred embodiment of 9 1 the invention 1 DESCRIPTION OF-PREFERRED EMBODIMENTS

1 11 Description is given of the details of the

12 1 invention with reference to the drawings attached here1 13 1 1 14 1 16 1 d 17 19 1 1 21 1 22 1 23 1 24 1 Fig.7 is a side elevatinnal view of tne turbine shown in Fig.6.

Fig.8 is a view showing the arrangement of a w 1 t h. (A first preferred embodiment) Generally speaking. the Doppler effect is pro- uced in a case where a pulsation source which generates pulsations of sound signals. electric signals and light, etc. and a subject which captures the abovementioned pulsations are moving relative to each other.

When the distance between the abovementioned Pulsation source and the subject which captures the pulsations is decreased. surplus signals are observed in a fixed duration of time to cause the frequency of the captured pulsations to be increased more than the inherent frequency of the pulsations. To the contrary. when 6 13AL) ORIGINAL JO 1 the distance between the pulsatien source ano the subject which captures the pulsations is increased. the frequency of the captured pulsations is decreased less than the inherent frequency thereof.

In the preferred embodiment. the rotation speed of an impeller disposed in a flow channel of the fluid to be metered is detected by utilizing the above Doppler effect.

1 2 3 4 6 7 1 is described with reference to Fig.2 to Fig.4. 1 is an 1 11 1 impeller which is caused to rotate by a flow force of 12 1 fluid. 2 is a laser beam or ultrasonic wave transmitter. 1 13 1 3 is a laser beam or ultrasonic wave recelver. 4 is a 1 14 1 cable for transmitting a signal received from the re- 1 ceiver 3. 5 is a cable for transmitting a transmission 16 1 signal to the transmitter 2, 6 is a circular tube in 17 1 which the abovementioned impeller 1. transmitter 2.

18 1 receiver 3. etc. are incorporated. 7 is an inputting 19 1 unit for inputting a signal received from the receiver 1 3. 8 is an outputting unit for outputting a transmission 21 1 signal to the transmitter 2. 9 is a data processing u 1 22 1 which obtains. through calculations, the difference 1 23 1 between the frequency captured by the receiver 3 and the 1 24 1 frequency transmitted by the outputting unit 8 and 1 1 calculates the rotation speed of the impeller 1 based ob The first preferred embodiment of the invention 7 BAD ORIGINAL 0 4) 1 1 the value thus obtained, and 10 is a flowmeter-display 1 2 1 for displaying the flow rate olotained from the rotation 1 3 1 speed of the impeller 1.

4 1 The action thereof is described below. As shown 1 in Fig.2, no mechanism for detecting the rotation.

6 1 including any mechanical factors. is connected to the 7 1 impeller 1. There-fore, as there is almost no element 8 1 which may resist the rotation of the impeller 1. it is 9 1 possible for the impeller 1 to instantaneously make a 1 faithful response to the flow of fluid. When fluid flows 11 1 inside the circular tube 6. for example. in the direc1 12 1 tion of the arrow B-B, the impeller 1 is caused to 13 1 rotate in the direction of the arrow C-C At this time. 1 14 1 as shown in Fig.3, a transmission signal is issued from 1 the transmitter 2 toward the tip end ld of the impeller 16 1 1. As a fixed relationship exists between the incident 17 1 angle and the reflection angle of the transmission 18 1 signal for the impeller 1. this transmission signal is 19 1 reflected from the tip end 1d of the impeller 1 at a 1 certain moment. and the receiver 3 captures the reflect- 21 1 ed signal. that is. the captured signal In this case.

ZZ 1 as the impeller 1 rotates at all the times. the distance 23 1 between the tip end Id of the impelLer 1 and the trans- 24 1 mitter 2 and the distance between the tip end Id of the 1 impeller 1 and the receiver 3 change to cause the Dop- 8 SAD OR)GMAL A0 ' 0 Q_.0..00 1 1 pier effect to be produCed. For this reason. as shown in 2 1 Fig.4, some change is produced in the frequency which lis 3 1 captured by the inputting unit 7 in comparison with the 4 1 frequency which is transmitted by the outputting unit 8, 1 the data processing unit 9 obtains the difference bet- 6 1 ween the frequency which the inputting unit 7 captures 7 1 and the frequency transmitted by the outputting unit 8 1 8 1 through calculations from this change. whereby the 9 1 rotation speed of the impeller 1 is detected. the veloc- 1 ity of the fluid is obtained. and the flow rate is 11 1 calculated an the basis of the metering position. sec12 1 tional area, etc. obtained from the diameter of the 13 1 circular tube 6. As described above, as no mechanism for 1 14 1 detecting the rotation Is attached directly to the 1 impeller 1. there is nothing which limits the size of 16 1 the impeller. Therefore. It is possible to make the 17 1 impeller very small. The smaller the impeller becomes. 1 18 1 the smaller the mass thereof becomes. whereby the in- 19 1 fluence due to inertia will be able to be made least.

1 For this reason. it is possible to achieve. detection of 21 1 high speed fluid and to make a response to instantaneous 22 J changes of the velocity.

23 1 Furthermore. in a case where a laser beam is 24 1 issued from the outputting unit 8. optical fiber is used 1 - 1 for the cable 5. and a transmitter 2 Of Optical system 9 BAD ORIGWAL 0) 2 1 3 4 6 1 7 1 1 12 13 14 is such as a lens is used. The output of the recever 3 of opticai system passes through the cable 4 such as opt! ca 1 f l be r. s i g n a.] line, etc, and is inputted in the inputting unit 7 The photocell etc.

If an ultrasonic laser beam. the cables 4 ultrasonic wave generat 1 oscillator is used fo uni r c c inp 1 of an using 16 1 ultrasonic 17 1 framework 18 1 of gears 19 1 thereof. 20 21 1 22 23 1 24 1 25 1 very smal inputting unit 7 is composed of a wave is used instead of the and 5 become a signal line. an or such as an ultrasonic wave r the transmitter 2 and outputting 8. an ultrasonic wave receiver may be used for the ivqr 3, and a signal amplifier is used for the tting unit 7.

From the above description. the rotation speed impeller (turbine) is metered and detected by the Doppler effect by utilizing a laser beam or wave, not depending upon any mechanical Therefore, as no influence such as backlashes e Lc. i s g iven to the me te r ing and de tec t ion a device such as an impeller is able to be made by utilizing micro machining techniques, and furthermore, it is possible to detect the flow rate of high speed fluids. and also possible to measure or meter non- steady flows regarding the fuel injection ratios etc of a fuel injection system. (A second preferred embodiment)

BAD ORIGINAL A0 3 4 6 7 9 1 1 10 1 12 1 1 13 1 14 1 16 1 1 17 18 19 21 zz 23 24 J are identijal to those in the f"rst Preferred embodiment are given the same numbers with. the de%cription thereof omitted. 12 is a transmitter as a transmitting means which transmits a laser beam or ultrasonic wave. The function of this transmitter is able to be changed so that it is used as a receiver (receiving means). 13 is receiver which captures a laser beam or ultrasonic wave. and the function of this receiver is able to be changed so that it means). 14 w i th the another c inputting unit 7 or outPutting unit 8. 16 switch for changing the connection of the and receiver 13 with the inputting unit 7 ting unit 8. 16a and 16b are contact poin switch 16. and 17 is a controller which controls the inputting unit 7, outputting unit 8 or the switch 16. Furthermore. the contact 16a is provided for changeover between the transmitter 12 and the receiver 13 or inputting unit 7 and the contact 16b is provided for changeover between the transmitter 12 and the receiver 13 or outputt ing unit 8 That is. when the receiver 13 i s d embodiment of the invenLion described with reference to Fig.S. The portions which is used as a transmitter (transmitting is a cable which connects the transmitter 12 inputting unit 7 or outputting unit 8. 15 is able which connects the receiver 13 with the is a change transmitter 12 or the outputs of the 11 BAD ORIGINAL 0 r 0 0 4 0 -. 4P 0 c 0 2 1 1 3 1 1 4 1 7 8 9 1 13 14 1 Is 16 17 is 19 20 21 1 22 23 1 24 25 onnected to the inputting unit 7 via the contact 16a.

1 1 1 1 1 b a s i c 1 the transmitter 12 is connected- to the outputting unit 8 via the contact 16b. On the other hand, when tne transmitter 12 is connected to the inputting unit 7 via the contact 16a. the receiver 13 is connected to the outputting unit 8 via the contact 16b.

N e x t, the action thereof i described below. The the first preferred embodiment. Therefore. only the portion, the action of which is different from that of the first preferred embodiment. is explained here. As shown in Fig.S. although the transmitter 12 is a transmitting means as well as the transmitter 2 in the abovementioned first p re f erred embod imen t. it is possible to change the unction thereof so as to function as a receiving means action is similar to that of 1 1 f 1 like the receiver 3. Furthermore. although the receiver 1 1 13 is a receiving means, it is able to be changed so as 1 1 to function as a transmitting means. The cables 14 and 1 15 which are respectively connected to the transmitter 1 1 12 and receiver 13 are able to transmit either of the 1 1 1 transmission signal or capturing signal.

For example. by utilizing the Doppler effect ex- Diained in the above first preferred embodiment, it is 1 possible to detect the flow direction which will be 1 1 explained below. Firstly. the transmitting means and 12 UAD ORIGINAL 03 1 1 1 2 3 4 1 eceiving means are set as defaults. the frequency of 1 the transmission signal is compared with thal. of the receipt signal by the data processing unit 9. In where the frequency of the transmission signal is lower than that of the receipt signal. the distance from the signal being reflected by the impeller 1 which is in thp. signal being captured by the receiving ned. It is assumed that this state is, at the impeller "rotates normally".

n a case where the frequency of the trans is higher than that of the receipt sign c from a signal being reflected by the impeller which is revolving to the signal being captured by the receiving means is lengthened. It is assumed that the state is, for reverse I y" is 1 of the fluid. Furthermor 1 revolution to 1 means is shorte 1 for example. th 1 Furthermore, 1 mission signal 1 al, the distanc example. that the impeller 1 "rotates possible to detect the flow direction c. in a case where the frequency of the above transmission signal is set in advance as a fixed value. the. value is compared with the frequency of signals captured by the receiving means, and the frequency captured by the receiving means is made smaller than the above set value. it is possible to detect that the flow direction of fluid has been changed to the reverse direction. The abovementioned set value may be a value which is processed by comparing the frequency of - OAD ORIGINAL 0 13 0) a 1h 0..01 -. a 0 4 1 7 1 9 1 12 1 1 13 1 1 14 1 1 is 1 1 is 17 1 18 19 1 1 lated by the data processing unit. 9. whereby the rota- 21 1 tion speed of the impeller 1 is detected, the velocity 22 1 of the fluid is obtained. and the flow rate is calculat23 1 ed based on information such as the metering position 1 24 1 and the cross-sectional area obtained by the inner 1 25 1 diameter of the circular tube 6.

signals transmitted by the frequency nf signals captur th i s t i me. it is possible t of the impeller 1 regardles 'this is the same even in a direction of the impeller 1 "Reverse rotation". is reve As described above. the flow direction detected 9. the controller 17 dete r transmitting means with the d by the receiving means. At otain the rotation speed of the rotation direction. ase where the rotation "Normal rotation" or s e d based on the output showing by the data processing unit ines a combination of the transmitter 12. receiver 13. inputting unit 7 and outputting unit 8. chances the switch 16, whereby the controller 17 connects the outputting unit 8 and transmitter 12 or the inputting unit 7 and receiver 13. and controls the inputting unit 7 and outputting unit 8. In a case where the switch 16 is changed. and the above connections are made, the difference of the frequency of signals transmitted by the transmitter 12 and the freP4uency of signals captured by the receiver 13 is caleu- 14 CAD ORIGINAL A0 2 3 4 6 7 1 1 12 13 14 16 17 18 19 21 1 22 1 23 24 1 1 25 1 1 reverse direction as described above, and the controller 1 17 changes the switch 16. connects the outputt ing unit 8 1 to the receiver 13 which functions as the transmitting 1 means. and connects the inputting unit 7 to the trans 1 mitter 12 which functions as the receiving means.

As described above. it is possible to detect the 1 flow rate and direction of the fluid in the circular 1 tube 6. Furthermore. by reversely changing the position 1 of the transmitter and rereiver along with the reversed 1 rotation direction of the impeller 1, it is possible to 1 detect the flow rate even though the impeller 1 rotates In a case where the fluid f!ows in the direction of the above description, the data unit 9 changes the flow direction to be detect reverse rocessing ed to the In either direction. (A third preferred embodiment) A third Preferred embodiment of the invention will be described with reference to Fig.3 to Fig.g. 30 is a minute turbine. 30a as a blade of the abovementioned turbine. 31 is a fuel channel in which the above- 1 mentioned turbine 30 ete is disposed. 32 is a light emitting element, 33 is a light receiving element disposed opposite to the abovementioned light emitting element 32, 34 is a light emitting unit which causes the light emitting element 32 to emit light. 33 is a calcu- PD OAIGINAL ZO) 1 1 1 lation unit which receivt.

2 1 outputted by the light re 1 3 1 the measured or metered value 1 4 1 36 is a transparent resin mold.

The action thereof wit 7 i 1 E) 9 1 2 1 3 1 4 17 1 1 21 22 23 24 third preferred embodimen of revolutions (frequency s a light receiving signal ceiving element 33 and obtains through calculations, and be described below. The t is able to detect the number) of the minute turbine 30 with 1 a photo sensor equipped with a light emitting element 32 1 1 and light receiving element 33. As the turbine 30 is not 1 directly provided with any mechanism consisting of mechanical components to detect the number of revolutions. no external force other than the fluid forc 1 etc. The appearance view of the minute turbine 30 is 1 shown in Fig 6 and Fig.7 As the turbine is minute, the 1 1 mass therenf is small and the inertia thereof will e is given to the turbine. Furthermore. as a photo sensor is employed for detection, the detection may be not hardly influenced by noises such as electro-magnetic waves.

become small, too. Therefore, the response is much 1 improved, and the turbine is durable against external impacts. Furthermore. as the load applied to the turbine is reduced due to a small pressure receiving surface. it is able to cope with high injection pressure. As the 1 outer diameter of the minute turbine 30 which is micro- 1 machined, it is able to be disposed without enlarging 16 BAD ORIGWAL 03 2 3 4 7 1 9 1 1 1 12 1 1 13 1 1 14 1 16 1 1 17 1 18 19 1 1 1 22 1 1 23 1 1 24 t 1 LED may 1 low sensi 1 1 ing eleme the outer diameter of the fuel distance between the light em light receiving element 33 is be used for the light tivity sensor may be n t 33 As shown in Fig.8. in a case where the turbine 30 is installed in a state that a part of the turbine is in contact with the fuel which flows in the fuel channel 31 of a diesel engine. the turbine 30 is caused to rotate in the direction of the arrow e-e if it is assumed that the fuel flowing direction is in the direction of the arrow d-d. At this time. as shown in Fig.g. the light emitting means and light receiving means are the portion of the turbine 30, which is not brought into contact with the flowing fuel. The light emitting means consists of a light emitting un.it 34 which causes the light emitting elements 32.32 to emit light. The light receiving means consists of a light receiving element 33. Output signals of the light receiving element 33 are inputted in the calculation unit 35. The light emitting element 32 and light emitting element 33 are fixed in the fuel channel 31 by a resin mold having a light penetration property For example. if it is assumed that the light emitting disposed opposite to each other at 17 channel 30. and as the tting eiernent 30 and the decreased. a low output emitting element 321 and a used for the light receiv- BAD ORIGINAL A0 49 4 6 7 1 1 12 13 14 15 16 17 18 19 20 21 22 23 24 25 lement 32 is composed of LED etc and the light emitting unit 34 is a driver circuit of the LED. the light which, s emitted by the LED is shielded by the blades 30a of the turbine 30, the light receiving element 33 such as a 1 Phototransistor etc is able 1 ween the blades 30a of 1 to receive light only bet- the turbine 30 to cause the light 1 receiving signals of the light receiving eIement 33 to 1 become pulse signals. The calculation unit 35 which i 1 calculating means counts these pulse signals. obtains 1 the number of revolutions of the turbine 30. that is.

1 the frequency of light receiving, meters the injection 1 duration of fuel, meters the injection ratic, of non- 1 steady flows in the duration of the above injection 1 meters the fuel injection rate per injection by inte- 1 grating the above injection ratio.

As described above, as the t 1 it does not constitute any resistance to the fluids. 1 1 Therefore. the fuel injection characteristics are not 1 influenced at all. Besides. as the inertia thereof is 1 small. the response is very quick. whereby it is possi- 1 ble to detect the injection ratios of non-steady f in the duration of injection. Furthermore. by integrat- ing the above injection ratio, it is possible to accu- 1 rately detect the fuel injection rate per in j ec t ion.

1 Still furthermore, as the number of revolutions of the urbine 30 is minute.

18 ELAD ORIGINAL A 1 2 3 4 5 6 7 a 9 1 1 12 13 14 1 means for transmitting a laser beam or ultrasonic wave 1 to the tip end of an impeller which is revolving. a 16 1 receiving means for capturing a laser beam or ultraso 17 1 wave reflected by the impeller, and a data processing 18 1 unit which obtains. through calculations. the difference 19 1 between the frequency of signals transmitted by the 1 transmitting means and the frequency of signals captured 21 1 by the receiving means and detects the rotation speed of 22 1 the impeller based on the value obtained therefrom, no 23 1 influence due to wearing of gears and backlashes is 1 24 1 brought. and it is possible to remarkably reduce an 1 1 impel ler type flowmeter and to detect the flow rate of a turbine is detecte other than the flULd force is itself, whereby i t is possible tr) accurate ly detect the flow rate without giving any influence to the fuel injection characteristics.

According to the invention as described above. s the flow rate by a photosensor. no external force given to the turbine of a fluid is able to be obtained by detecting the rotation speed of an impeller disposed in a flow channel of the fluid to be metered, it is possible to detect an instantaneous rotation speed of the impeller and to meter nonsteady flows. according to the invention composed as there are provided a transmitting Espec ial ly 1 as shown in Fig.4 1 19 n i c BAD ORIGINAL JO 2 1 3 J 4 1 5 6 7 1 1 12 13 14 is 16 17 18 19 21 22 23 24 1 t 25 1 i F i 5 as to high speed fluid. Still furthermore. it is possible to detect an instantaneous rotation speed of an impeller and to meter the non-steady flows.

According to the invention composed as shown in the transmitting means is able to be changed so function as a receiving means. and the receiving means is able to be changed so as to function as the transmitting means, these means are changed on the basis of the flow direction detected by the. data processing unit, and the above data processing unit is devised to calculate the difference between the frequency of signals transm itted by the transmitting means and the frequency of signals captured by the above receiving means. Therefore, it is possibie to detect the rotation speed according to the flow direction even though the impeller is caused to rotate in either direction.

Furthermore. especially. in a cast where the data Processing unit is composed so that. when the value obtained by comparing the frequency of signals transmitted by the transmitting means with that of signals captured by the receiving means is made smaller than the Preset value. the detecting direction of the fluid 1 flowing direction is changed to be. reversed, it is Possible to detect the rotation speed of the impeller and at the same time to detect the flox. direc BAD ORGINAL A 0 0 0 0 0 c 0 0 0!!:.

2 3 4 7 e 1 13 1;4 1 15 16 1 7 18 19 20 21 22 23 24 25 1 1 1 1 f 1 U i d Acc 1 Fig.6 to Fig,g. as a turbine is di.-p,)sed n a fuel 1 1 channel in a diesel engine, a light emitting means and light receiving means are disposed opposite to each other with the turbine placed therebetween. and the injection ratio. injection time and injection rate are 1 able to be metered based on the frequency obtained by 1 the above light receiving means. it is possible to accurately detect the influence to the injection characteristics Furthermore. the response to changes of th ording to the invention compgscd as shown in flow"rate without giving any of fue 1 flowrate is much improved. and it is possible to detect the injection ratio of non-steady flows in the duration of injec- 1 t ion a b 1 c Still furthermore. the pressure receiving area is to be much reduced. and it is possible to cope with a high injection Pressure. Besides, the inertia is reduced by making the turbine mass smaller. whereby the strength against external impacts 1 Still furthermore, it is possible t 1 igh r c c e 1 igh s ma 1 duce s much improved.

o use a low output t emitting element and a low sensitivity light iving element by making the Interval between the t emitting element and light receiving element 1. thereby causing the production cost to be red. A photo sensor is utilized to detect the number 21 v BAD ORIGINAL J61 3 received. 4 1 6 1 of revolutions of the turbine. therebY causing influen.:

es due to magnetic electricity. ete no', to be 14 1 16 1 17 1 18 1 19 21 23 1 1 24 1 1 1 BAD ORIGINAL A0 22 2 1 4 1 1 12 13 14 15 16 17 is 19 20 21 22 23 24 25 1

Claims

1 What is claimed is'.

1. A flowmeter being characterized in obtaining the flow rate of fluids by detecting the rotation speed of an impeller disposed in a flow channel of the fiuid to be metered.

2. Flowmeter according to claim 1, characterised in that the transmitter (12) is able to be changed so as to flinction as a receiver, that the receiver (13) is able to be changed so as to flinction as a transmitter, that the transmitter (12) and the receiver (13) are designed so as to be changed on the basis of the flow direction detected by the data processing unit (9) and that the data processing unit (9) calculates the difference between the frequency of signals transmitted by the transmitter and that of signals captured by the receiver.

Flowmeter according to claim 1 or 2, characterised in. that the data processing unit (9) conducts the calculation with respect to a preset frequency value, and reversely changes the working direction of the flowmeter, when the vAuc,o.btained by comparison of the frequencies of transmitter signal and receiver signal.is. smalbet thim the preset frequency value.

2-5.

2. A flowmeter set forth in claim 1. comprising transmitting means for transmitting a laser beam or ultrasonic wave to the tip end of the impeller which is revolving; a receiving means (or capturing the laser beam or ultrasonic wave reflected by the impeller; and a 1 data processing unit which obtains, through calcula tions. the difference between the frequency of signals transmitted by the transmitting means and the frequency 1 of signals captured by the receiving means. and detects the rotation speed of the impeller from the value ob- tained therefrom.

3. A flowmeter set forth in claim 2. being characterized in that a transmitting means is able to be changed so as ta function as a receiving means, a receiving 1 means is able to be changed so as to function as a 1 transmitting means. and these means are constructed so 1 as to be changed on the basis of the flow direction 1 detected by a data processing unit. and that the data 1 processing unit calculates the difference between the 1 frequency of signals transmitted by the transmitting 23 BAD ORIGINAL 0) wee 1 1 1 means and that of signals captured by the receiving 2 3 4 5 6 7 means.

1

4. A flowmeter set flyrth in claim 2. being character- ized in that, in a f lowme ter which detects the rotat.on speed of an impeller on the basis of the value obtained 1 by calculating the difference between the frequency of 1 signals transmitted by the transmitting means and the 8 1 frequency of signals captured by the receiving means, 9 1 the data processing unit causes the detecting direction 1 of the fluid flowing direction to be reversely changed 11 1 in a case where the value obtained by comparing the 1 12 1 frequency of signals transmitted by the transmitting 13 1 means with the frequency of signals captured by the 14 1 receiving means is made smaller than the preset value.

1

5. A flowmeter being characterized in having a turbine 16 1 disposed in a fuel channel in a diesel engine. having a 1 17 1 light emitting means and a light receiving means dis- 18 19 1 21 1 22 23 24 1 posed opposite to each other with the turbine placed therebetween. and being equipped with a calculating means for metering the injection ratio. injection time and injection rate based on the frequency of signals captured by the receiving means.

24 aAO ORIGINAL 0 4) 0 0 1 CLAIMS Amendments to the claims have been filed as follows 1. Flowmeter for a fluid flowing in a flow channel (6), especially fuel for a fuel injection device, comprising:

an impeller (1) extending into the fluid and being rotated by the fluid, wherein the rotational speed of the impeller is measured without any mechanical force transmission means.

a transmitter (2; 12) for laser beams or ultrasonic waves, from which the laser beams or ultrasonic waves are transmitted to the tip of the blades of the rotating impeller (1), a receiver (3; 13) for receiving the laser beams or ultrasonic waves reflected from the impeller (1), and a data processing unit (9), characterised in that the data processing unit (9) obtains, through calculations, the difference between the frequency of signals transmitted by the transmitter (2; 12) and that of sl,ú,m--a-l-s captured by the receiver (3; 13) and calculates the rotational speed of the impeller (1) from the value obtained therefrom.