JPS6025724B2 - level detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a liquid level detection device using an optical method.

Conventionally, fricto level switches have often been used to detect water and sludge.

This level switch had a float installed in a water tank, and a switch inside the float responded to changes in level and detected the level as an ON/OFF electrical signal. However, with this method, if the float or underwater cable is damaged, there is a risk of electrical leakage, which is dangerous for humans and livestock. Furthermore, when used at a low voltage to reduce leakage current, it has the disadvantage that long-distance transmission is difficult and it is susceptible to external noise. An object of the present invention is to provide an optical level detecting device that performs level detection using light so that there is no fear of electrical leakage and can be constructed as a completely leak-proof type.

The present invention will be explained below with reference to an embodiment shown in the drawings.

FIG. 1 shows an embodiment of the invention. 1 is a float, and the solid line part of the float 1 has the liquid 12 at a low level, and the float 1 is in a suspended state before operation.

On the other hand, the broken line float 1 indicates that the liquid 12 has reached a high level and the float 1
This shows the operating state when the machine is tipped on its side. Floater 1 is shown in cross section to explain the inside. Reference numeral 5 indicates a head-shaped support for fixing the float in a tank (not shown); 3 indicates a reflective surface that reflects light irradiated from an optical fiber 2, which will be described later; and 4 indicates, for example, a powder that moves on the reflective surface depending on the movement of the float 1. It is a non-reflective material.

The optical fiber 2 described above is for transmitting and receiving light, and consists of two lines, one for transmitting light and one for receiving light. 6 A bell detector transmits and receives light,
The level of liquid 12 is ultimately converted into an electrical signal.

This level detector 6 is usually installed far away from the detected part. When the liquid 12 is at a low level, the light emitting part 7 constantly emits light, and the light 9 is irradiated into the float 1 through the optical fiber 2.

However, inside the float 1, the non-reflector 4 moves vertically due to its own weight.
That is, since it is placed on the bottom of the reflective surface 3, the light 9 is not reflected and the light receiving section 8 does not sense the reflected light. In other words, it is in an inactive state. A diagram of this principle is shown in FIG. On the other hand, when the liquid 12 reaches a high level, the float 1 floats to the position indicated by the broken line as indicated by the arrow 11, and the non-reflector 4 moves in the vertical direction. That is, the reflective surface at the bottom is exposed. Light 9 transmitted from the optical fiber 2 is reflected by the reflective surface 3, passes through the light-receiving line of the optical fiber 2, and is sensed by the light-receiving section 8, so that an output 10 is obtained. A diagram of this principle is shown in FIG. As described above, the level detection device according to the present invention converts into electrical signals at a distance, so there is no risk of electrical leakage or heat generation in the water tank, so it is suitable for level detection not only of water and sludge, but also of flammable and explosive liquids. suitable.

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram showing one embodiment of a level detection device according to the present invention, and FIGS. 2 and 3 are partial diagrams illustrating the principle when it is not in operation and when it is in operation. 4...Float, 2...Optical fiber, 3...
... Reflective surface, 4... Non-reflector, 5... Support, 6... Detector, 7... Light emitting part, 8...
····Light receiving section. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1. A hollow float that is supported so that its support angle changes according to liquid level fluctuations, a reflective surface partially provided on the inner surface of this float that reflects light, and a reflecting surface that is provided inside the float and that changes its angle. a non-reflector that moves freely on a reflective surface as a result of the movement, an optical fiber that transmits and receives light and whose inner end of the float faces the reflective surface, and a light-emitting part and a light-receiving part provided on the other end of the optical fiber. A level detection device comprising: a detector having a section;