CN1093463A - The limit liquid level telltale - Google Patents
The limit liquid level telltale Download PDFInfo
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- CN1093463A CN1093463A CN 93114493 CN93114493A CN1093463A CN 1093463 A CN1093463 A CN 1093463A CN 93114493 CN93114493 CN 93114493 CN 93114493 A CN93114493 A CN 93114493A CN 1093463 A CN1093463 A CN 1093463A
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Abstract
A kind of container limit liquid level telltale comprises pulse signal generator; Be arranged in the container and the output terminal of process RC circuit and generator electrode even; The electronic switch that its control input end is connected with the output terminal of selector switch; The video signal device that is connected with latter's output terminal; And constitute and be connected beeper between electrode and the selector switch input end by current occuring circuit.When electrode not during contact liq, on the non-inverted output terminals of selector switch, form the electric signal of conducting electronic switch, so video is switched on.This device can be used for various liquid, comprising the low liquid of conductivity.
Description
The present invention relates to measuring technique, specifically, relate to the limit liquid level telltale.Its application comprises the liquid level control of the corrosive liquids in the various containers, and spraying plant, water barrow, automotive engineering equipment etc. for example are used for applying fertilizer.
The limit liquid level telltale is widely used in the technical equipment.The device of known this purposes has BrP No. 2117910, the GIH class.During this device work, signal sends device from signal and arrives amplifier through controlled fluid, arrives on-off element then.When electrode contacts disconnects with controlled medium, the on-off element work in the device, pilot lamp is lighted.This device is mainly used to control the controlling level of loose stacking yard material, often needs repacking again when using it for liquid.
Also know a kind of device of measuring the liquid limit liquid level, it is to control by means of two these liquid levels of electrode pair, the signal that sends from these two electrodes compares every certain time interval, count by trigger circuit, then, signal arrives display (seeing the GOIF23/00 class Jap.P. 4-61286 number).But this apparatus features is the circuit complexity, lacks enough reliabilities, and can not adopt automatic working method.
No. 3136864, Deutsche Bundespatent, the described device of GOIF23/24 class comprises two electrodes that are immersed in the controlled fluid.Because descending, the liquid level of controlled fluid cause the electrical connection between two electrodes to be interrupted, so the signal of relevant this situation just arrives display.This device can only be worked reliable just now under the situation of conductive liquid.
Jap.P. 2-33967 number, the magnitude relationship of the electric conductivity of described technical scheme of GOIF23/24 class and controlled fluid is little.Its circuit parameter is chosen such that to be when filling printing ink in the storage tank, and electrode just is immersed in the printing ink, and constant and variable input impedance are numerically about equally.When electrode in case disengage with printing ink, the RC electric bridge is out of trim just, so form display source signal.The shortcoming of this scheme is the influence that its sensitivity meeting is disturbed by temperature variation and power supply noise.In addition, this device can not be general without exception to various liquid.
Therefore, the device of above-mentioned all determination limit liquid levels all is only with the foundation that act as of the conductivity of controlled liquid medium, and this point has also just determined their limitation in application facet.
What approach device that the present invention recommends in known each device most is container limit liquid level telltale, and it comprises pulse signal generator, electrode, selector switch, electronic switch and video signal device.Electrode is located in the container, is connected with the output terminal of signal generator by the RC circuit; The control input end of electronic switch is connected with the output terminal of selector switch; Video signal device is connected (seeing Deutsche Bundespatent No. 312626105, the GOIF23/24 class) with the output terminal of electronic switch.
In said apparatus, the mensuration of liquid level is to adopt to realize in the mode of comparer as selector switch in the container, directly arrive an input end of selector switch from the signal of pulse signal generator, then arrive another input end of selector switch from pulse signal generator, through the signal of RC circuit and electrode.When liquid contacted with electrode, because the by-passing of conductive liquid, the signal amplitude on the 2nd input terminal of comparer was less than on the 1st input terminal.When electrode did not contact with liquid, the signal on two input ends of comparer equated.Therefore, the difference between the signal on two of comparer input ends just represents that electrode and liquid contact with each other.From the signal process electronic switch of comparer output, row control during to video signal device.
It is such that the shortcoming erect image front of this device is analyzed, and its possibility of its application only limits to a certain concrete liquid.When changing a kind of liquid into another kind of liquid, and its conductivity is when being another numerical value again, and device just can not guarantee to send reliable limit liquid level signal, because variation has taken place for the difference of the signal on the comparator input terminal and the relation between the initial set value.The numerical value of the conductivity of liquid is more little, and the reliability that known devices is measured liquid level is low more, and this is because the signal difference on two input ends of comparer reduces.For non-conductive (or weak inductive) liquid, known devices is helpless basically.
The objective of the invention is to enlarge the range of application of limit liquid level telltale, can use it for various liquid,, do not reduce the reliability of work simultaneously again comprising the low liquid of conductivity.
The method of finishing above-mentioned task is to comprise pulse signal generator, electrode, selector switch, the 1st electronic switch, video signal device in container limit liquid level telltale.Electrode is located in the container, is connected with the output terminal of pulse signal generator by the RC circuit; The control input end of the 1st electronic switch is connected with the output terminal of selector switch; Video signal device is connected with the output terminal of the 1st electronic switch.Increase an amplitude transformer in addition, it is made of the current feedback circuit circuit, is connected between the input end of electrode and selector switch.Selector switch adopts the form of amplifying circuit, and it has paraphase output terminal and non-inverted output terminals, cross-over connection capacitor between two output terminals.
Preferably load onto same shaft housing to electrode, and at the above-mentioned insulation course of adorning between the two.The 1st electronic switch of device can be constituted by transistor.
The amplifying circuit of selector switch can also adopt another way, promptly adopts band to cut apart the transistor cascade circuit of load, cross-over connection capacitor between its emitter circuit and collector circuit.
In device, can also increase a buffer amplifier, it is connected between the output terminal and RC circuit of signal generator.
In the container of being recommended, the limit liquid level telltale preferably replenishes again and adorns a beeper.It is made of the 2nd electronic switch and piezoelectricity radiator.A contact of piezoelectricity radiator is connected to the output terminal of pulse signal generator by the 2nd electronic switch, and the control input end of the 2nd electronic switch is connected with the output terminal of the 1st electronic switch.
If use beeper, preferably increase a phase inverter and the 3rd electronic switch to it again, they are connected between the 2nd contact of the output terminal of the 2nd electronic switch and piezoelectricity radiator, and the control input end of the 3rd electronic switch is connected in the output terminal of the 1st electronic switch simultaneously.
When using beeper, preferably replenish one the 2nd buffer amplifier to it again, connect between the 1st contact of the output terminal of the 2nd electronic switch and piezoelectricity radiator.
At last, when piezoelectricity radiator and phase inverter, the 2nd on-off element and the 3rd on-off element are used in the lump, but the 3rd on-off element transistor constitutes cross-over connection diode between its collector and emitter.
Now utilize description of drawings the present invention.
Fig. 1 is the electric component circuitry schematic diagram of container limit liquid level telltale, divides by functional block among the figure.
Fig. 2 is the wiring diagram between electronic unit, electrode and the load.
Fig. 3 is one of electrode structure example.
Fig. 4 a is when electrode does not contact with liquid, the voltage U at contact 6 places among Fig. 1
1Curve map.
Fig. 4 b is a voltage U when electrode contacts with liquid
2Curve map.
Container limit liquid level telltale comprises pulse signal generator 1(Fig. 1); Coupling RC circuit 2; Electrode 3(Fig. 2), signal amplitude transducer 7, selector switch the 11, the 1st electronic switch and beeper 16.Electrode 3 be arranged in the container 4 that fills liquid 5, and be connected (Fig. 1) at contact 6 places with the output terminal of pulse signal generator 1; Signal amplitude transducer 7 is the current feedback circuits that are made of transistor 8, resistance 9 and 10, is connected at contact 6 places with electrode 3; Selector switch 11 constitutes cross-over connection capacitor 14 between these two output terminals by the amplifying circuit of band paraphase output terminal 12 and non-inverted output terminals 13; The input end of the 1st electronic switch 15 is connected on the output terminal of selector switch 11; Beeper 16 is connected with the output terminal of the 1st electronic switch 15.
Electrode 3 is contained in (Fig. 3) in the shell 17, and insulate by insulation course 18, this insulation course by, for example, the dichloride thorium is made (TOPON
ACT).
The 1st electronic switch can be by two (or more) single transistors 19,20(Fig. 1) the transistor combinational circuit that constitutes constitutes.
In this organization plan, selector switch 11 is to adopt transistor 21 to form, and pull-up resistor 22,23 is connected in collector circuit and the emitter circuit, that is to say, parts 11 are by amplifying circuit or amplifier stage and cut apart load and constitute.
Put in the connection circuit this, on pull-up resistor 22, isolate the paraphase output signal at contact 12 places, and on resistance 23, isolate the noninvert output signal at contact 13 places.Cross-over connection capacitor 14 between paraphase output terminal 12 and non-inverted output terminals 13.
In order to disconnect cascade each other, and, buffer amplifier 24 is connected between pulse signal generator 1 and the RC circuit 2 for the amplifying signal amplitude.In this topology example, this amplifier is made of two phase inverters 25,26 of parallel connection.
According to actual conditions, beeper 16 can constitute by diverse form.Already be reduced to the information limit below with the liquid level in the container wherein the most suitable comprising, notifying operation personnel's (driver, spinner) video signal device and beeper, and both can use separately, also can be used.
In the embodiment of said vesse limit liquid level telltale, beeper 16 serves as that the basis constitutes with piezoelectricity radiator 27, as seen from Figure 1, a contact of its top is by the 2nd electronic switch 28, be connected the output terminal (perhaps being connected the output terminal of buffer amplifier 24) of pulse signal generator 1, the 2nd electronic switch is made of transistor 29, and its base stage output terminal is the control input end of switch, and is connected to the output terminal of the 1st electronic switch 15 by resistance.The 2nd contact of piezoelectricity radiator 27 is (from Fig. 1, the contact of below) can be connected with common line, that is perhaps implemented in the image pattern 1 is such, be connected to by phase inverter 30 on the output terminal of the 2nd electronic switch 28, also comprise the 3rd electronic switch 31 in the beeper 16, it is made of the transistor 32 of band build-out resistor 33, and its base stage output terminal is the control input end of switch, and is connected with the output terminal of the 1st electronic switch 15.Cross-over connection diode 34 between the collector and emitter of transistor 32.
In order to amplify the volume of beeper, between the output terminal of the 2nd electronic switch 28 and the 1st contact of piezoelectricity radiator 27 (from Fig. 1, the contact of top), connect the 2nd buffer amplifier, in should use-case, its function be finished by phase inverter 35.
Remaining element adopts habitual element in the circuit theory diagrams (Fig. 1) of device, and gets final product according to the circuit connecting method of common employing.
Therefore, pulse signal generator 1 is made of two routine phase devices 36 and 37, and the positive feedback with frequency dependence between the two realizes by resistance 38 and electric capacity 39.
Electric capacity the 48, the 49th, filter element is used for reducing the pulsation in the power circuit and the influence of high-frequency induction.
The circuit component of device is concentrated on the printed circuit board (PCB), constitute electronic unit 50.Parts 50 are terminal with the terminal strip 51 of band connection terminal 52,53,54,55.The positive voltage of external power supply (not shown) is added in (Fig. 2) on the terminal 52.Lamp 56 and fuse 57 as video signal device are connected on the connection terminal 53.Terminal 54 is public terminal (ground connection, shells).Terminal 55 is connected with electrode 3.
Container limit liquid level telltale working condition is as follows:
Therefore, if liquid level no show electrode 3, then liquid this electric signal is not exerted an influence, so exist as Fig. 4 a(U at contact 6
1Curve map) cyclical signal shown in.If electrode 3 immerses liquid 5, then the electric signal at contact 6 places is U
2Waveform shown in the curve map (Fig. 4 b).U
2With U
1Compare, can find out 2 differences at least: the one, the amplitude of signal obviously reduces, and this had both depended on the influence of the conductivity of liquid 5, depended on the influence of dielectric property again; The 2nd, the waveform of pulse signal significantly changes, and its reason only is to be subjected to the influence of the dielectric property of liquid 5.Therefore, the liquid level of the liquid 5 in the signal amplitude at contact 6 places and waveform and the container 4 is relevant.
Signal amplitude transducer 7 is made of the current occuring circuit of transistor 8, be used for the amplitude of signal is carried out shaping, promptly tie the non-linear partial of transition characteristic, the big signal of amplitude is restricted, and the little signal of amplitude obtains amplifying owing to the P-n of transistor 8 in the foregoing circuit.Certainly, this shaping is only carried out within the specific limits, and the amplitude of signal only reaches metastable stage just now at the output terminal of transducer 7.
If electrode 3 is immersed in the liquid 5, that is to say when liquid level has surpassed limit liquid level the U among the waveform of the electric signal on the input end of transducer 7 and Fig. 4 b
2The curve unanimity.At U
2For on the occasion of a period of time between in, transistor 21 conductings of selector switch 11, if at this moment there is not capacitor 14, just so can it two on output terminal, at contact 12 and contact 13 reversed phase signal and noninvert signal appear respectively promptly.But, under the situation that capacitor 14 is arranged, and at the U of the circuit of selector switch 11
2Rise very slowly and stably under the condition, the signal that forms opposed polarity at contact 12 and 13 places just is bound to be removed.
The voltage of result on addition resistor 23 in fact with zero indistinction, this situation is corresponding to the closure state of electronic switch 15,28,31, the result disconnects beeper 16 and video signal device-lamp 56.
Therefore, be immersed in the liquid 5(liquid level liquid level that oversteps the extreme limit at electrode 3) situation under, device does not produce shows signal.
If electrode 3 is in the outside of liquid 5, promptly for a certain reason, liquid level drops to below the limit liquid level, and then liquid does not have influence to signal amplitude on the contact in the circuit shown in Figure 16 and shape ripple, then the signal on the contact 6 have with Fig. 4 a in curve U
1The same shape.The part of this signal is subjected to the weakening of amplitude converter 7 (restriction), and arrives the input end of selector switch 11.Because in this case, work as U
1For on the occasion of the time, signal raises rapidly (the leading edge slope is big), so capacitor 14 21 discharges of the transistor by being actually conducting equally soon, circuit has lost the ability of eliminating the signal on the contact 12 and 13.Therefore at point 13, on addition resistor 23, isolate positive signal.At U
1Be the synchronization of negative value, transistor 21 ends, and capacitor 14 is slowly charged by power supply through the big relatively resistance of resistances 22,23, that is to say that in this case capacitor 14 is carried out integrating functions.The result forms on the non-inverted output terminals 13 of selector switch 11 is actually constant positive voltage, and this voltage is with electronic switch 15 conductings.External power supply so lamp 56 is lighted, sends the signal about liquid level value of reaching the limit of of the liquid in the container 45 through the electronic switch 15 of lamp 56, fuse 57, contact 53, conducting, then make current flowing through common line and contact 54.
When sending vision signal, also send acoustical signal.Really be at electronic switch 15 under the state of conducting, the voltage on the collector output of transistor 19,20 is similar to zero, and this just is equivalent to electronic switch 28,31 and is in conducting state.At this moment be cushioned the 2nd electronic switch 28 and the 2nd buffer amplifier 35 of the signal of the pulse signal generator 1 that amplifier 24 amplified through conducting, arrive the top contact (from Fig. 1) of piezoelectricity radiator 27, and arrive the below contact (from Fig. 1) of piezoelectricity radiator 27 through the 3rd electronic switch 31 of phase inverter 30 and conducting.By the circuit that connects by this way, make the different pulse signal of polarity arrive two contacts of piezoelectricity radiator 27, this has just determined that certainly the volume of acoustical signal increases.
By as can be known through last explanation of the present invention, the present invention is different from analogue means and old device, in the device of being recommended, at the contact mensuration of being carried out of liquid with electrode, it or not the variation of only depending on the conductivity of electrode surrounding medium, but also depend on the variation of its dielectric coefficient, and what play a decisive role is a kind of factor in back.Therefore the device that the present invention recommended is in the reliability that guarantees to have height aspect the limit liquid level of measuring various liquid (comprising weak inductive liquid).
The container limit liquid level telltale of being recommended can be applicable to industrial various fields and various technological process, and all require in these fields and process provides the liquid level about controlled fluid to drop to the information below the limit to operating personnel high-effectly.
The pioneer field of using is automobile transportation and water barrow, and in these fields, this device can send water effectively, add the limit liquid level signal of saline solution and freeze-point depressant etc.
This device can be used to send the limit liquid level signal of corrosive liquids, because electrode surface in fact can be by galvanic corrosion.Level sensor is worked under the condition of medium temperature from-55 ℃ to+150 ℃ of pressurizations around, and electronic unit is in-50 ℃ again in+60 ℃ scope, and under the condition that has high power pulse to disturb, its parameter can not change.
Claims (9)
1, container limit liquid level telltale comprises pulse signal generator (1), electrode (3), selector switch (11), the 1st electronic switch (15), video signal device (56); Electrode is contained in the container (4), and is connected with the output terminal of generator (1) through RC circuit (2); The control input end of the 1st electronic switch (15) is connected with the output terminal of selector switch (11); Video signal device (56) is connected with the output terminal of the 1st electronic switch (15), being characterized as of this device: increased an amplitude converter (7) in the device, it is made of current occuring circuit, is connected between the input end of electrode (3) and selector switch (11); And selector switch (11) constitutes with the form of amplifying circuit, and this circuit has paraphase output terminal (12) and non-inverted output terminals (13), cross-over connection capacitor (14) between these two output terminals.
2, device according to claim 1 is characterized by: shell (17) is housed and between above-mentioned insulation course (18) between the two on the electrode (3).
3, according to 2 described devices of claim 1, it is characterized by: the 1st electronic switch is made of interwoven crystal pipe (19,20).
4, according to claim 1 and 2 described devices, it is characterized by: the amplifying circuit of selector switch (11) is by transistor (21) and cut apart load cascade formation, cross-over connection capacitor (14) between transistorized emitter output terminal (13) and collector output (12)
5, according to claim 1 and 2 described devices, it is characterized by: increased a buffer amplifier (24) in the device, it is connected between the output terminal and RC circuit (2) of pulse signal generator (1).
6, device according to claim 1, it is characterized by: beeper (16) is housed on the device, it is made of the 2nd electronic switch (28) and piezoelectricity radiator (27), the latter's a contact is connected the output terminal of pulse signal generator through the 2nd electronic switch (28), and the control input end of the 2nd electronic switch (28) is connected with the output terminal of the 1st electronic switch (15).
7, device according to claim 6, it is characterized by: beeper (16) is equipped with phase inverter (30) and the 3rd electronic switch (31), their levels are associated between the 2nd contact of the output terminal of the 2nd electronic switch (28) and piezoelectricity radiator (27), and the control input end of the 3rd electronic switch (31) is connected with the output terminal of the 1st electronic switch (15).
8, according to claim 6 and 7 described devices, it is characterized by: beeper is equipped with the 2nd buffer amplifier (35), and it is connected between the 1st contact of the output terminal of the 2nd electronic switch (28) and piezoelectricity radiator (27).
9, according to claim 7 and 8 described devices, it is characterized by: the 3rd electronic switch (31) is made of transistor (32), and between current collection-emitter a diode of cross-over connection (34).
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| RU92010091 | 1992-12-16 | ||
| RU92010091A RU2010498C1 (en) | 1992-12-16 | 1992-12-16 | Device for indicating critical liquid level |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN1093463A true CN1093463A (en) | 1994-10-12 |
Family
ID=20133154
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 93114493 Pending CN1093463A (en) | 1992-12-16 | 1993-12-16 | The limit liquid level telltale |
Country Status (2)
| Country | Link |
|---|---|
| CN (1) | CN1093463A (en) |
| RU (1) | RU2010498C1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110673664A (en) * | 2019-10-25 | 2020-01-10 | 北京和隆优化科技股份有限公司 | Optimized control method for liquid level of salt melting barrel |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104677460B (en) * | 2015-03-23 | 2018-01-16 | 上海理工大学 | Liquid level detection device |
-
1992
- 1992-12-16 RU RU92010091A patent/RU2010498C1/en active
-
1993
- 1993-12-16 CN CN 93114493 patent/CN1093463A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110673664A (en) * | 2019-10-25 | 2020-01-10 | 北京和隆优化科技股份有限公司 | Optimized control method for liquid level of salt melting barrel |
Also Published As
| Publication number | Publication date |
|---|---|
| RU2010498C1 (en) | 1994-04-15 |
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| C06 | Publication | ||
| PB01 | Publication | ||
| C01 | Deemed withdrawal of patent application (patent law 1993) | ||
| WD01 | Invention patent application deemed withdrawn after publication |