CN104180872A - Contactless liquid level meter - Google Patents

Abstract

The invention discloses a contactless liquid level meter comprising a tank, a laser transmitter, an upper hole, a lower hole and a scale sensor. Both the laser transmitter and the scale sensor are arranged at the outer top end of the tank, and an included angle is formed between the laser transmitter and a plumb line. The laser transmitter is provided with a first wire connected with a power source. The upper hole is arranged in the top end of the tank, and the lower hole is arranged in the bottom end of the tank. The contactless liquid level meter has the advantages that tested liquids cannot be polluted; the contactless liquid level meter cannot be polluted by the tested liquids and cannot be shielded by algae, water scale and the like in water; scales are prevented form being unclear due to liquid corrosion; accuracy is prevented from being affected due to temperature variation; the contactless liquid level meter is unaffected by other physico-chemical properties of the tested liquids, thereby being applicable to all liquids; measuring accuracy can be higher; automatic measurement is easier to realize.

Description

A kind of contactless liquid level meter

Technical field

The present invention relates to a kind of contactless liquid level meter.

Background technology

Liquid level detects, and has a wide range of applications, as hydrologic observation, laboratory reagent discharge observation, boiler liquid level, boiler liquid level, water heater liquid level, fuel of internal combustion engine or lubricating oil liquid level etc.

The liquid level checking method using at present, mainly contains: 1. rule is directly measured; 2. the position moving up and down by ball float is measured; 3. use linker, liquid level is extracted to measurement; 4. utilize the electrical property of liquid, change or proximity transducer principle is measured etc. by resistance or electric capacity

The shortcoming of these measuring methods has above:

1) connect with liquid, easily polluted by fluid to be measured, some can be corroded, thereby some necessarily has color make scale unintelligible etc. because liquid itself has;

2) utilize fluid to be measured electricity characteristic measuring, due to different fluids to be measured, electrology characteristic difference, thereby different liquids can only use specific measurement parameter.If use capacitance characteristic to measure, other character such as temperature also can affect the specific inductive capacity of liquid, thereby affect measuring amount accuracy;

3) measure with the position of ball float, due to the impact of ball float position, thereby measurement range is restricted;

4) measure for a long time the water surface, may make because of depositions such as water bath or incrustation scales scale fuzzy or ball float quality is changed.

Summary of the invention

Goal of the invention: the invention provides a kind of laser beam irradiation liquid level that adopts, by the contactless liquid level meter of reflective spot position judgment liquid level.

Technical scheme: for solving the problems of the technologies described above, the present invention adopts following technical scheme:

A kind of contactless liquid level meter, comprises casing, generating laser, upper hole, lower hole and scale sensor; Described generating laser and scale sensor are all located at the top outside casing, and generating laser and vertical direction form angle, and described generating laser is provided with the first wire that connects power supply; Described upper hole is located at the top of casing, and lower hole is located at the bottom of casing.

The angle a of above-mentioned generating laser and vertical direction is the incident angle of light; When contactless liquid level meter uses, the first wire that is communicated with power supply provides power supply for generating laser, lower hole enters casing for fluid to be measured, if level change is very fast or the more sticky hole of descending of flowing fluid ratio is suitably strengthened, upper hole is for gas turnover, so that the liquid level in casing keeps flushing with the liquid level outside casing, the angle of generating laser and vertical line does not change after fixing.

The angle that above-mentioned generating laser and plumb line form, between 0-90 °, is preferably 30-60 °.

Principle of work: the contactless liquid level meter of the present invention is used with liquid level off plumb generating laser and irradiated liquid level, liquid level reflection lasering beam, the angle of generating laser and plumb line is a, scale sensor and minimum level distance are H, liquid level (liquid level to be measured and liquid level distance of the end) is x, the distance of reflected light position and generating laser point of fixity O is y, and on scale sensor, corresponding scale reading is z, from geometry:

$\mathrm{tga}=\frac{\frac{1}{2}y}{H-x}---\left(1\right)$

After abbreviation: y=-2 (tga) x+2Htga is (2)

Because generating laser and vertical line angle are a, scale level (if out-of-level, taking advantage of a corresponding coefficient value), the position of laser beam and photographic plate is fixed, as long as the angle of laser beam and tested liquid level does not change, (2) the linear relationship of formula is constant.

In the situation that incoming laser beam is constant, for different liquid levels, the laser beam position difference reflecting, the distance of reflected light position z and generating laser point of fixity O is y, according to formula [2], y is the linear function of liquid level x, and reflection light point position z indication scale sensor high scale reading is corresponding with y numerical value, thereby is known liquid level according to y value.

The span of laser instrument deviation angle a is: the maximum height of establishing liquid level is X', and maximum scale is Y' apart from O point distance, according to Fig. 2, the peak excursion angle A of generating laser ' be:

$A\text{'}=\mathrm{arctg}\frac{\frac{1}{2}Y\text{'}}{H-X\text{'}}---\left(3\right)$

If apart from O point position, with Y, ", the smallest offset angle A of generating laser " is minimum scale:

$A\text{'}\text{'}=\mathrm{arctg}\frac{\frac{1}{2}Y\text{'}\text{'}}{H}---\left(4\right)$

The scope that is laser instrument deviation angle a is:

$\mathrm{arctg}\frac{\frac{1}{2}Y\text{'}\text{'}}{H}<a\&le;\mathrm{arctg}\frac{\frac{1}{2}Y\text{'}}{H-X\text{'}}---\left(5\right)$

In formula (5), maximum angle be the best angle of laser instrument skew.

Described scale sensor is photographic plate or index dial, can indirectly or directly read liquid level.

Described photographic plate is provided with the second wire that connects signal processes and displays instrument, can convert reflected light information of diverse location on photographic plate to electric signal, thus indrect reading.

Above-mentioned photographic plate is semi-conducting material manufacturing, can convert the light signal of diverse location to corresponding electric signal, and the second wire sends corresponding electric signal to treatment facility.

Described casing top is also provided with chaining, can be in the situation that liquid level do not fluctuate (in water heater, boiler is medium), and adopt the mode hanging to measure liquid level.

The mode that above-mentioned employing is hung, utilizes Action of Gravity Field, makes its heavy straight (when manufacture, noting the assurance of center of gravity), in the situation that liquid level has vibration, needs band damping unit, measures in order to avoid swing Datong District's impact.

Described cabinet wall is provided with coarse elastomeric layer, can absorb ripples, avoid tested liquid level be subject to outside liquid level impact.

Described casing is cuboid box body structure, can further avoid tested liquid level be subject to outside liquid level impact.

The NM technology of the present invention is prior art.

The contactless liquid level meter of the present invention:

1) do not pollute fluid to be measured;

2) can not polluted by fluid to be measured;

3) can not be subject to bath class, incrustation scale etc. in water body blocks;

4) can not make scale fuzzy because of liquid corrosion;

5) if scale sensor is carried out constant temperature work (measurement higher to accuracy requirement, installs thermostat additional), can not affect precision because of temperature variation;

6) be not subject to the impact of other physico-chemical properties of fluid to be measured, be applicable to all liq;

7) measuring accuracy can be higher;

8) be easier to realize automatic measurement.

Brief description of the drawings

Fig. 1 is the contactless liquid level meter of the present invention structural representation;

Fig. 2 is the contactless liquid level meter of the present invention scale reading schematic diagram;

Fig. 3 is that the contactless liquid level meter of the present invention uses constitutional diagram;

Fig. 4 is the out-of-level state measurement schematic diagram of the embodiment of the present invention 2 scale;

In figure, 1 is casing, and 2 is generating laser, 3 is the first wire, and 4 is upper hole, and 5 is lower hole, 6 is scale sensor, and 7 is the second wire, and 8 is chaining, 9 is tested container, and 10 is signal processes and displays instrument, and 11 is power supply, C1 is liquid level to be measured, C2 is liquid level of the end, and C3 is interior liquid level, and C4 is outer liquid level.

Embodiment

In order to understand better the present invention, further illustrate content of the present invention below in conjunction with embodiment, but content of the present invention is not only confined to the following examples.

Embodiment 1

Contactless liquid level meter as shown in Figure 1-Figure 3, comprises rectangular parallelepiped casing 1, generating laser 2, upper hole 4, lower hole 5 and scale sensor 6; Described generating laser 2 and scale sensor 6 are all located at the top outside casing 1, and generating laser 2 with the angle a of vertical direction is described generating laser 2 is provided with the first wire 3 that connects power supply 11; Described upper hole 4 is located at the top of casing 1, and lower hole 5 is located at the bottom of casing 1; Scale sensor 6 is index dial; Casing 1 inwall is provided with coarse elastomeric layer.

When use, contactless liquid level meter is put into the tested container 9 that fills testing liquid, the testing liquid in tested container 9 enters casing 1 inside by lower hole 5, until the outer liquid level C4 in the interior liquid level C3 of casing 1 and tested container 9 maintains an equal level, now, interior liquid level C3 is liquid level C1 to be measured; Use again with liquid level off plumb generating laser 2 and irradiate liquid level C1 to be measured, liquid level C1 reflection lasering beam to be measured, generating laser 2 is a with the angle of plumb line, scale sensor 6 is H with minimum level distance, liquid level (liquid level C1 to be measured with the end liquid level C2 distance) is x, the distance of reflected light position and generating laser 2 point of fixity O is y, and on scale sensor 6, corresponding scale reading is z, from geometry:

$\mathrm{tga}=\frac{\frac{1}{2}y}{H-x}---\left(1\right)$

After abbreviation: y=-2 (tga) x+2Htga is (2)

Because generating laser 2 is a with vertical line angle, when scale level, the position of laser beam and index dial is fixed, as long as the angle of laser beam and liquid level C1 to be measured does not change, (2) the linear relationship of formula is constant; Due to scale and liquid level linear relationship, be straight line if the container of liquid is housed for erecting wall, capacity and scale are linear relationship.

In the situation that incoming laser beam is constant, for different liquid levels, the laser beam position difference reflecting, the distance of reflected light position z and generating laser 2 point of fixity O is y, according to formula [2], y is the linear function of liquid level x, and reflection light point position z indication index dial high scale reading is corresponding with y numerical value, thereby is known liquid level according to y value.

Embodiment 2

Substantially the same manner as Example 1, difference is, scale sensor 6 is photographic plate, and photographic plate is provided with the second wire 7 that connects signal processes and displays instrument 10; Casing 1 top is also provided with chaining 8.

When use,, contactless liquid level meter is hung in the tested container 9 that fills testing liquid, testing liquid in tested container 9 enters casing 1 inside by lower hole 5, until the outer liquid level C4 in the interior liquid level C3 of casing 1 and tested container 9 maintains an equal level, now, interior liquid level C3 is liquid level C1 to be measured; In the situation that liquid level does not fluctuate, (in water heater, boiler is medium), utilizes Action of Gravity Field, make contactless liquid level meter heavy straight (noting the assurance of center of gravity when manufacture), in the situation that liquid level has vibration, need band damping unit, measured in order to avoid swing Datong District's impact; Then use with liquid level off plumb generating laser 2 and irradiate liquid level, liquid level reflection lasering beam, generating laser 2 with the angle of plumb line is scale sensor 6 is H with minimum level distance, liquid level (liquid level C1 to be measured with the end liquid level C2 distance) is x, the distance of reflected light position and generating laser 2 point of fixity O is y, and on scale sensor 6, corresponding scale reading is z, from geometry:

$\mathrm{tga}=\frac{\frac{1}{2}y}{H-x}---\left(1\right)$

After abbreviation: y=-2 (tga) x+2Htga is (2)

Because generating laser 2 is a with vertical line angle, when scale is out-of-level, take advantage of a corresponding coefficient value, as shown in Figure 4, an angle θ if photographic plate and surface level tilt, it is y (y=-2 (tga) x+2Htga) that reflection ray was irradiated to the distance that the point on the horizontal line that O orders orders to O, and being irradiated to the distance that the point on photographic plate orders apart from O is Z, from the angular relationship shown in figure and geometric knowledge:

Upper two formulas are merged to abbreviation to be obtained:

In the time that photographic plate and surface level tilt an angle θ, actual scale Z with for the scale y when tilting takes advantage of a coefficient, this coefficient is:

Because incident angle a is less than 90 °, known, in the time of θ=0, δ=1, Z=y

Due to scale and liquid level linear relationship, be straight line if the container of liquid is housed for erecting wall, capacity and scale are linear relationship, if upper lower wall is not linear, by revising, make scale same linear with appearance body.

In the situation that incoming laser beam is constant, different liquid levels, the laser beam position difference reflecting, by measuring reflection light point position z, the distance of reflected light position z and generating laser 2 point of fixity O is y, and photographic plate is semi-conducting material manufacturing, converts the light signal of diverse location to corresponding electric signal, the second 7, wire sends corresponding electric signal to signal and processes and display device, thereby determines liquid level.

The above is only the preferred embodiment of the present invention; be noted that for those skilled in the art; under the premise without departing from the principles of the invention, can also make some improvements and modifications, these improvements and modifications also should be considered as protection scope of the present invention.

Claims (6)

1. a contactless liquid level meter, is characterized in that: comprise casing (1), generating laser (2), upper hole (4), lower hole (5) and scale sensor (6); Described generating laser (2) and scale sensor (6) are all located at the outer top of casing (1), and generating laser (2) forms angle with plumb line; Described generating laser (2) is provided with the first wire (3) that connects power supply (11); Described upper hole (4) is located at the top of casing (1), and lower hole (5) is located at the bottom of casing (1).

2. contactless liquid level meter as claimed in claim 1, is characterized in that: described scale sensor (6) is photographic plate or index dial.

3. contactless liquid level meter as claimed in claim 2, is characterized in that: described photographic plate is provided with the second wire (7) that connects signal processes and displays instrument (10).

4. contactless liquid level meter as claimed in claim 1, is characterized in that: described casing (1) top is also provided with chaining (8).

5. the contactless liquid level meter as described in claim 1-4 any one, is characterized in that: described casing (1) inwall is provided with coarse elastomeric layer.

6. the contactless liquid level meter as described in claim 1-4 any one, is characterized in that: described casing (1) is rectangular parallelepiped casing (1) structure.