JPS59138924A - Liquid-level measuring device - Google Patents

Abstract

PURPOSE:To realize simplified and efficient measuring operation by fitting a weight made of a prism body for forming an optical path of reflection atop of a wire wound around a take-up reel. CONSTITUTION:The take-up reel 2 fitted to a supporting frame 1 is wound with the wire 3 constituted by coating a main conductive wire 6 and an auxiliary wire 7 with synthetic resin 8 and providing a scale to the outside, and the weight 9 which consists of a dry battery 10, light source 11, switch 12 for turning on and off the light source 11, photoelectric converter 13, and signal processing circuit 14 is fitted atop of the wire 3. When the wire 3 is unwound and the weight 9 is dipped in liquid, light from the light source 11 is not reflected totally by surfaces aa' and bb' of the prism of the weight 9 and the photoelectric converter 13 decreases in the amount of photodetection. At this time, the scale on the wire 3 is read to detect the liquid level.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a liquid level measurement method that optically measures a liquid level.
Regarding.

Conventionally, in order to measure how much liquid is in a ship's last tank or fuel tank, a steel tape 21 (made of steel for measurement) is used to measure the amount of liquid in a ship's last tank or fuel tank. Tape measure) and sounding scale (
Shout out to Eve 22 and others, pull up and check to see how much liquid is present, apply yellow powder Y called Water Ribbon 23 to the area that seems to be near the water surface, and lower it again. Next, when he pulled it up, the part R that had been soaked in the liquid had turned red, and by looking at it he knew that it was a liquid bone.

However, with this method, it is necessary to lower the sounding tape 21 at least twice each time in order to check and eliminate the density of the liquid. My father needed skill to apply the water ribbon 23, and since the water ribbon 23 would stain the steel tape 21, he had to wipe the steel tape 2I thoroughly every time he measured. In addition, their clothes were dirty and the work was unpleasant.

The present invention has been made in view of the above circumstances, and its purpose is to optically detect the liquid level using a prism body, thereby making measurement work efficient and simple in a short time. The purpose of this project is to develop a liquid level measuring device that can be used for various purposes.

That is, in the present invention, a weight made of a prism body that forms a reflective optical path is attached to the tip of a wire wound on a take-up reel, and a light source is disposed within the weight and on the reflective optical path of the light emitted from the light source. It is characterized by being equipped with a converter and a signal processing circuit that detects the liquid level based on the signal from the converter.

The present invention will be described below based on illustrated embodiments.

FIG. 2 shows the surface measuring device. In this device, a winding reel 2 is attached to a support frame I, and a wire 3 is wound around the winding reel 2, as shown in FIG. This take-up reel 2 is provided with a detection light 4. The wire 31 is wound and unwound using a winding I/window 5, and as shown in FIG. F? It is composed of E and is attached to the r1 hemorrhoid on the outside.

A weight χ1!9 made of a glass prism body is attached to the tip of the wire 3. This weight 9 has a pointed end at a right angle, as shown in FIG. -9 Inside the weight 9 are a dry battery 10, a light source 11 connected to it, and a light source 1.
A photoelectric converter 13 and a signal processing circuit 14 connected to the photoelectric converter 13 are further provided. The photoelectric converter 13 is disposed on the reflection optical path of the light emitted from the light source 11 passing through the level gauge 15, as shown in FIG. 1, and receives the light from the light source II. The signal processing circuit 14 is activated by the switch 12, detects the night scene based on the signal from the photoelectric converter 13, and connects the output to the detection light 4 via the above-mentioned king wire 6 and auxiliary wire 7. ing. That is, this signal processing circuit I
4, when the number of eras received by the photoelectric converter 13 is greater than a predetermined number, the output current becomes zero, and when the amount of light received by the photoelectric converter 13 is smaller than the predetermined value, the output type mC is bW. Note that 16 in the figure is a shielding plate that prevents light from the light source 11 from directly entering the photoelectric converter 13.

Next, the operation of this liquid level gauge 1fl11 device will be explained.

The general principle will be explained with reference to FIG. 3. Ox,
If you first turn on the light source II as shown in the same figure (a),
The light travels inside the weight 9 like an arrow and passes through the photoelectric converter 13.
Enter. If it is lit in the air, a a'
, b On the b' plane, total reflection of light occurs, and the photoelectric converter I
3 has Hikari 7II! Almost 100% of the light from No. 11 enters the room.

Next, when this weight 9 is brought close to the liquid surface and the tip of the weight 9, that is, the part where the optical path is reflected, is in a state of being immersed in the liquid surface, total reflection will no longer occur on the a a', b b' surfaces. , part of the light escapes into the water, and the light that reaches Motosa Henkei 13 becomes insignificant.

Therefore, by connecting a signal processing circuit 14 to this light converter 13, it is possible to detect water contact, that is, the arrival of the weight 9 at the liquid level, by a change in the signal of the light reaching the photoelectric converter 13. I can do it.

This will be explained in detail next.

Since the apex angle of the weight 9 is perpendicular, the light from the light source 13 hits the aa' plane at an angle of 45° for incidence. At this time, depending on the material that forms this optical path (for example, acrylic resin, glass, etc.),
In order for total reflection to occur on the aa' plane, the following conditions are required for the absolute refractive index of the substance.

If the absolute refractive index of the substance is 01, then the critical angle θC at which total reflection occurs is (Loo: 1 in the refractive index of air) Since the intervening angle is 45°, total reflection occurs on the a-a' plane. To do this, 45°〉θC...Listen to 1 song.
T ("oI" condition is necessary.

Glass has an absolute refractive index of 1.73 (5<1.73)
Satisfy the conditions.

Next, it is assumed that this weight 9 comes into contact with the liquid surface. The absolute 1-meter refractive index of this liquid is assumed to be 02. If r is the refraction angle of the path of light into the liquid that is reflected by the reflected portion of the weight 9 on the liquid surface, the following equation holds true.

no2Sjn45゜7L + 2-:□ ・・・・・・・
...... (5) rLol 5Inr Now, if total reflection occurs at the surface a a' and its refraction pr is exactly 900, then the critical circle is 4
Since it is 5°, rLo2 SI [145° 1 ” 2” FLOI = 5i1190' = J”'E
””” (6'no 2 ”,z rLol-…
°−−f7) Also, from equation (5) above, rL01 ”°′=I complete °°゛°“−=゛=−+81sin
r=”ol...
...... Song... (9+Taru02 Therefore...>E...
...Track...Track 4... αQ Therefore, r<90°, no total reflection occurs, most of the light escapes into the liquid, and the photoelectric converter 13 has only one Only the reflected light from the area reaches the target. Furthermore, since this light quantity is reflected from both sides of aa' and bb/, it is proportional to the square of the reflectance.

Now, if η・ol is glass (absolute refractive index 1.73), then n 02 > 1.223 ・-=・=-... Curb・(Ill.Water's refractive index is about 1.33) Awa,
Most oils have a higher refractive index than water. This method therefore allows sounding of water and many highly transparent oils.

Note that the apex angle of the weight 9 is not perpendicular to the right angle, and may be any other angle. Further, the material forming the optical path is not limited to glass, and may be other materials.

Next, the operation of this liquid level measuring device will be explained. In FIG. 2, the m++ determiner first presses the switch 12 attached to the weight 9, turns on the light τ source 11, and activates the signal processing circuit I4. In this state, the weight 9 is gradually lowered into the sounding pipe 22 as shown by the symbol @4, and the weight 9 is brought closer to the liquid surface. The absolute refractive index of the liquid when the weight 9 comes into contact with the liquid surface, or more precisely, when the level gauge 15 comes into contact with the water, is defined as Le 02. If r is the refraction angle of the path of light into the liquid where the reflective part of the weight 9 is in contact with the liquid surface, the following equation holds true.

・, 2-y=sin45°, 8500116800.
(5 nors oISl [lr Now, if total reflection occurs at the surface a a' and the refraction angle r is exactly 90°, then the critical angle is 4
Since it is 5°, let r″0 be 1--!-... (6) not
811190 Nitai 5 (7) Also, from the above formula (5), rLo2= 41 ・・・・・・・・・・・・
・・・・・・ +8J 5lnr Sjn r = −! -Star, 1010001311
110011. (9) J"i no2 Therefore, if rLOH> Hnot, 5tor
<1 ...... Song...14 〇〇Therefore, r〈90°, total reflection does not occur, most of the light escapes into the liquid, and the photoelectric converter 13 Only a portion of the reflected light reaches . Also, this amount of light is a a' and b
Since it is reflected on both sides of b', it is proportional to the square of the reflectance.

If we assume that Ru01 is glass (absolute refractive index 1.73), then riot > 1.223...
・・・・・・・・・・・・ It is OD. The refractive index of water is about 1.33, and most oils have a refractive index lower than that of water. This method therefore allows sounding of water and many highly transparent oils.

Note that the apex angle of the weight 9 is not limited to a right angle, and may be any other angle.

The material forming the single optical path is not limited to glass, but may be other materials.

Next, the operation of this liquid level measuring device will be explained. In FIG. 2, the measurer first presses the switch 12 attached to the weight 9, turns on the light gamma source II, and turns on the signal processing circuit 14.
Activate. In this state, as shown in FIG. 4(a), the weight @9 is gradually lowered into the sounding pipe 22, and the weight 9 is brought closer to the liquid level. When the weight 9 comes into contact with the liquid surface, or more precisely, when the level gauge 15 comes into contact with the water, the signal processing circuit I4 converts the change in photoelectricity into a current, and current flows through the main wire 6 and the auxiliary wire 7 of the wire 3. , the detection light 4 lights up. The measurer reads the reading at this time using a scale attached to the wire 3 (Sa in FIG. 4(a)). ←
If there is an arrangement table (which allows you to know the depth of the liquid and the amount of liquid by knowing the distance from the top of the sounding pipe to the liquid level). The measurement ends with this. -arrow≠≠ki; If there is no rate table, lower the weight 9 further and take the reading on the scale cable at the time of lowering it in the trench that reaches the bottom of the sounding pipe 22 (Sb in Fig. 4 (D)).

By adding the distance d between the level gauge 15 and the tip of the weight 9 to this difference, this is the depth of the liquid to be determined. That is, the depth D of the liquid is expressed as D=31)-8a+d.

As described above, according to the present invention, since the position of the liquid level is determined optically using the refractive index of the liquid, measurement can be performed by simply lowering the wire once, and measurement can be carried out in a short time and with high efficiency. . Historically, the device is simple, can be produced at low cost, and has remarkable effects such as easy maintenance.

[Brief explanation of the drawing]

Fig. 1 7d is an explanatory diagram of a conventional liquid level detection device, Fig. 2 (
b) is an overall view of a liquid level detection device showing an embodiment of the present invention;
The same figure (b) is an enlarged view of part A in Fig. 2 (a), the same figure (c) is an enlarged view of part B in Fig. 2 (a), and (in the same figure) is an enlarged view of part A of Fig. 2 (a).
Figures 3(a) and 3(b) are diagrams explaining the action, and Figures 3(a) and 3(b) are explanatory diagrams showing the operating method. I... Support frame, 2... Take-up reel, 3... Scale wire, 4... Detection light, 5... Winding handle, 6... Main wire, 7... Auxiliary wire , 8... Synthetic resin, 9... Weight, 10... Dry battery, 11... Light source, 12... Switch, 13... Photoelectric conversion layer, 14...
...Signal processing circuit, 15...Level gauge, I6...
・Diagram 1 m2 (a) Procedural amendment dated 8th, 15th, and 15th of Showa Kazuo Wakasugi, Commissioner of the Patent Office 1, Indication of the case, Patent Application No. 14006, 1982, 2, Title of the invention Liquid level measuring device: 36 Relationship with the case of the person making the amendment Patent applicant (620) Mitsubishi Heavy Industries, Ltd. Iso Agent 7, Contents of the amendment (1) Specification Toyonaka No. 3 Negative Line 20 (2 "Tip") (2) In the 9th negative line 7 of the same page and the 11th line of the same page, the words ``arrangement'' are corrected to ``arrangement.''

Claims (1)

[Claims] A weight consisting of a prism body that forms a reflected optical path is attached to the tip of a wire wound on a take-up reel, and a light source is placed within the weight and a light beam conversion system is placed on the reflected optical path of the light emitted from the light source. l'Pj, surface resistance 1111 device, characterized in that it has a signal processing circuit for detecting the liquid level based on a signal from the optical absorption converter.