CN201837432U - Liquid level detection device - Google Patents
Liquid level detection device Download PDFInfo
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- CN201837432U CN201837432U CN2010205807885U CN201020580788U CN201837432U CN 201837432 U CN201837432 U CN 201837432U CN 2010205807885 U CN2010205807885 U CN 2010205807885U CN 201020580788 U CN201020580788 U CN 201020580788U CN 201837432 U CN201837432 U CN 201837432U
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Abstract
The utility model discloses a liquid level detection device, which comprises a signal source, a frequency output electrode, a frequency input electrode and a frequency-voltage converter. When liquid level of liquid to be detected reaches a preset position, the liquid is contacted with the frequency input electrode, the liquid to be detected is used as a coupling medium, so a preset frequency signal generated by the signal source is drawn into the input end of the frequency-voltage converter; and since the liquid to be detected only influences amplitude of the signal and is free from changing the frequency of the signal, i.e. the signal frequency obtained by the frequency-voltage converter is identical to that of the signal generated by the signal source, therefore, a stable voltage signal is obtained after the signal which is transferred by the liquid to be detected to the frequency-voltage converter is processed in frequency-voltage conversion, then the stable voltage signal is compared with a preset liquid threshold value voltage through a voltage comparator, and an output voltage is obtained to be transmitted to a detection system, so the liquid reaching signal can be precisely detected, and the structure is simple.
Description
Technical field
The utility model relates to the Level Detection technical field, particularly relates to a kind of liquid level detection device.
Background technology
At present, the liquid level detection by quantitative adopts photoelectricity, ultrasound wave, pressure survey to realize that above-mentioned level gauging precision is mostly more than 0.5-2mm usually.Prior art also has a kind of method of utilizing dividing potential drop to compare and measure the liquid level that different electricity lead, and this method is utilized the conductive characteristic of electric drain, but because the resistance variations of electric drain liquid level is very big to the amplitude attenuation of voltage, therefore has the unsettled phenomenon of measuring accuracy.
The water gaging precision of calorimeter need reach in 1 gram in the coal analysis instrument, be converted into area then page precision measure need reach below the 0.1mm, at present, in calorimeter, adopt mechanical systems such as balance, measuring cup, weighing to realize Level Detection usually, but complicated in mechanical structure is bulky, automaticity is not high.Therefore, be badly in need of a kind of simple structure and high-precision liquid level detection device.
The utility model content
For solving the problems of the technologies described above, the utility model embodiment provides a kind of liquid level detection device, and to solve the liquid level detection device complex structure in the existing calorimeter, the problem that bulky automaticity is not high, technical scheme is as follows:
A kind of liquid level detection device comprises:
Can produce the signal source of predeterminated frequency signal;
Be arranged in the solution to be detected, and the frequency output electrode that links to each other with the output terminal of described signal source;
One end is positioned at the frequency input electrode at default liquid level place;
The frequency-voltage converter that input end links to each other with the other end of described frequency input electrode;
The voltage comparator that links to each other with the output terminal of described frequency-voltage converter.
Preferably, described liquid level detection device also comprises: be arranged on the wave filter between described frequency-voltage converter output terminal and the voltage comparator.
Preferably, described liquid level detection device also comprises: the level converter that links to each other with the output terminal of described voltage comparator.
Preferably, described signal source is for producing the signal source of predeterminated frequency positive-negative phase variable signal.
The technical scheme that is provided by above the utility model embodiment as seen, the frequency output electrode is arranged on the constant signal of frequency that in the solution to be detected signal source is produced and is incorporated in the solution to be detected, liquid to be detected is equivalent to couplant, be provided with the frequency input electrode at default liquid level place, when the liquid level of liquid to be detected reaches predeterminated position, contact with the frequency input electrode, at this moment, liquid to be detected is as couplant, the predeterminated frequency signal that signal source is produced is introduced in the input end of frequency-voltage converter, because solution to be detected only influences the amplitude of signal, and do not change the frequency of signal, the frequency of the signal that to be the signal frequency that obtains of frequency-voltage converter produced with signal source is identical, therefore, pass to the signal of frequency-voltage converter by solution to be detected, after the voltage to frequency conversion, obtain stable voltage signal, utilize voltage comparator that stable voltage signal and the Level Detection threshold voltage of presetting are compared again, obtain output voltage and flow to detection system, can accurately detect the liquid level arriving signal, and simple in structure.
Description of drawings
In order to be illustrated more clearly in the utility model embodiment or technical scheme of the prior art, to do to introduce simply to the accompanying drawing of required use in embodiment or the description of the Prior Art below, apparently, the accompanying drawing that describes below only is some embodiment that put down in writing in the utility model, for those of ordinary skills, under the prerequisite of not paying creative work, can also obtain other accompanying drawing according to these accompanying drawings.
Fig. 1 is the structural representation of a kind of liquid level detection device of the utility model embodiment;
Fig. 2 is the structural representation of the another kind of liquid level detection device of the utility model embodiment.
Embodiment
In order to make those skilled in the art person understand technical scheme in the utility model better, below in conjunction with the accompanying drawing among the utility model embodiment, technical scheme among the utility model embodiment is clearly and completely described, obviously, described embodiment only is the utility model part embodiment, rather than whole embodiment.Based on the embodiment in the utility model, those of ordinary skills are not making the every other embodiment that is obtained under the creative work prerequisite, all should belong to the scope of the utility model protection.
Referring to Fig. 1, Fig. 1 is the structural representation of a kind of liquid level detection device of the utility model embodiment, and this device mainly comprises: signal source 110, frequency output electrode 120, frequency input electrode 130, frequency-voltage converter 140, voltage comparator 150.
The utility model adopts positive negative square-wave signal as signal source 110, this signal frequency is about about 7.6kHz, voltage range is about-10V～+ 10V, adopt positive negative square-wave signal can effectively prevent the plating of described frequency output electrode 120 and frequency input electrode 130.The utility model employing model is that the chip of OPA627 obtains described square wave, certainly, also can use other signals generation chips or discrete component to obtain the square-wave signal that needs.
In addition, can also carry out modulation treatment according to the anti-interference situation of signal, described modulation is meant the process that low-frequency signals is loaded into a certain fixed RF vibration, with convenient low-frequency signals is carried out long-distance transmissions and extraction.
It is frequency-pressure/pressure-frequency conversion chip realization of AD650 that frequency-voltage converter 140 can adopt model, can certainly use other to press conversion chip to realize frequently according to concrete voltage or frequency requirement.
When the liquid level of solution to be detected slowly rises to predetermined position, contact with frequency input electrode 130, at this moment, there is certain conductivity (inverse of resistance) in solution to be detected between frequency output electrode 120 and the frequency input electrode 130, this resistance is the couplant that frequency output electrode 120 and frequency input electrode 130 frequency signals transmit, because this resistance variations is bigger to the influence of voltage of signals amplitude, thereby causes bigger error when level gauging.But therefore the resistance of solution, adopt the frequency transformation method can detect having or not of liquid level accurately to the not influence of frequency of signal, also can realize quantitative accurately simultaneously.
Concrete, the signal that signal source 110 is produced is delivered to frequency-voltage converter 140 through solution to be detected.Because the variation of electric drain liquid resistance can not exert an influence to the frequency of signal, so the electric signal that frequency input electrode 130 is introduced obtains the stable signal of voltage magnitude, so that next step detection after frequency-voltage converter 140 conversions.
The first input end of voltage comparator 150 is connected with the output terminal of frequency-voltage converter 140, the default liquid level threshold voltage vt h of second input end input of voltage comparator 150, the relatively size of the predetermined threshold value voltage Vth of the magnitude of voltage of first input end input and second input end.
When the liquid level of liquid to be detected did not touch described frequency input electrode 130, the voltage signal amplitude of frequency-voltage converter 140 outputs was less than described default liquid level threshold voltage vt h; When the liquid level of solution to be detected touches frequency input electrode 130, the voltage signal amplitude of described frequency-voltage converter 140 outputs is greater than described default liquid level threshold voltage vt h, described default liquid level threshold voltage vt h can set according to the output voltage values of frequency-voltage converter, and described liquid level threshold voltage vt h is slightly less than the magnitude of voltage of described frequency-voltage converter output.
The liquid level detection device that the utility model provides, the frequency output electrode that utilization is arranged in the solution to be detected is incorporated into the predeterminated frequency signal that signal source produces in the solution to be detected, be provided with the frequency input electrode at default liquid level place, when the liquid level of liquid to be detected reaches predeterminated position, liquid to be detected is as couplant, the signal of the predeterminated frequency that described signal source is produced is incorporated into the input end of frequency-voltage converter, because described solution to be detected only influences the amplitude of signal, and do not change the frequency of signal, therefore, pass to the signal of frequency-voltage converter by solution to be detected, after the voltage to frequency conversion, obtain stable voltage signal, utilize voltage comparator that described stable voltage signal is compared with the Level Detection threshold voltage vt h that presets again, obtain output voltage and flow to detection system, this liquid level detection device can accurately detect the liquid level arriving signal, and simple in structure, the automaticity height.
Referring to Fig. 2, the structural representation of the another kind of liquid level detection device that Fig. 2 provides for the utility model on the basis of liquid level detection device shown in Figure 1, has increased wave filter 210 and level converter 220.
Between the first input end of the output terminal of described frequency-voltage converter 140 and voltage comparator 150, increased wave filter 210, be used for signal filtering, guaranteed that the voltage signal of output of frequency-voltage converter 140 is stable.
Concrete, described wave filter 210 can utilize electric capacity, resistance to realize that the span of described electric capacity and resistance is determined according to actual conditions.
The output terminal of voltage comparator 150 is connected with level translator 220, and level translator 220 can convert the voltage signal of voltage comparator 150 outputs to voltage signal that liquid level detection system can directly read, thereby realizes detecting automatically liquid level.
Each embodiment in this instructions all adopts the mode of going forward one by one to describe, and what each embodiment stressed all is and the difference of other embodiment that identical similar part is mutually referring to getting final product between each embodiment.
The above only is an embodiment of the present utility model; should be pointed out that for those skilled in the art, under the prerequisite that does not break away from the utility model principle; can also make some improvements and modifications, these improvements and modifications also should be considered as protection domain of the present utility model.
Claims (4)
1. a liquid level detection device is characterized in that, comprising:
Can produce the signal source of predeterminated frequency signal;
Be arranged in the solution to be detected, and the frequency output electrode that links to each other with the output terminal of described signal source;
One end is positioned at the frequency input electrode at default liquid level place;
The frequency-voltage converter that input end links to each other with the other end of described frequency input electrode;
The voltage comparator that links to each other with the output terminal of described frequency-voltage converter.
2. liquid level detection device according to claim 1 is characterized in that, also comprises the wave filter that is arranged between described frequency-voltage converter output terminal and the voltage comparator.
3. liquid level detection device according to claim 2 is characterized in that, also comprises the level converter that links to each other with the output terminal of described voltage comparator.
4. according to each described liquid level detection device of claim 1 to 3, it is characterized in that described signal source is for producing the signal source of predeterminated frequency positive-negative phase variable signal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010205807885U CN201837432U (en) | 2010-10-27 | 2010-10-27 | Liquid level detection device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010205807885U CN201837432U (en) | 2010-10-27 | 2010-10-27 | Liquid level detection device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN201837432U true CN201837432U (en) | 2011-05-18 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2010205807885U Expired - Lifetime CN201837432U (en) | 2010-10-27 | 2010-10-27 | Liquid level detection device |
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| Country | Link |
|---|---|
| CN (1) | CN201837432U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101975603A (en) * | 2010-10-27 | 2011-02-16 | 长沙开元仪器股份有限公司 | Liquid level detector |
-
2010
- 2010-10-27 CN CN2010205807885U patent/CN201837432U/en not_active Expired - Lifetime
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101975603A (en) * | 2010-10-27 | 2011-02-16 | 长沙开元仪器股份有限公司 | Liquid level detector |
| CN101975603B (en) * | 2010-10-27 | 2015-05-20 | 长沙开元仪器股份有限公司 | Liquid level detector |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| AV01 | Patent right actively abandoned |
Granted publication date: 20110518 Effective date of abandoning: 20150520 |
|
| RGAV | Abandon patent right to avoid regrant |