JPH0672077U - Liquid detector - Google Patents

Abstract

(57) [Summary] [Purpose] To ensure that the presence or absence of liquid can be detected regardless of the transparency of the liquid. [Structure] The light receiver 3 is arranged with respect to the light projector 2 so as to have a predetermined angle (θ) so that the light projected from the light projector 3 can be received as reflected light by the liquid on a surface orthogonal to the moving direction of the liquid. It is set up.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an apparatus for detecting the presence or absence of a highly transparent oil agent or a liquid such as an aqueous solution.

[0002]

[Prior art]

 Generally, when detecting a liquid such as an oil solution, an aqueous solution, or a synthetic resin liquid that is supplied continuously or intermittently, a liquid projector and a light receiver are sandwiched between the liquid and a direction orthogonal to the moving direction of the liquid. A device is used which is arranged linearly and is in a light-shielded state when liquid is supplied, and when the supply of liquid is interrupted, the light from the projector is detected by a light receiver.

When detecting the presence or absence of a highly transparent liquid that is continuously supplied by using such a device for detecting the presence or absence of the liquid based on the light receiving state of the light from the light projector, the light from the light projector is used. Since most of the light is transmitted, the difference in the amount of light received when the liquid is being supplied and when the supply of the liquid is stopped is very small, making it very difficult to reliably detect the presence or absence of the liquid.

In the case of intermittently supplying a highly transparent liquid in the form of liquid drops, the liquid drops drop and first pass through the light projecting unit, and finally pass through the light projecting unit. The light is reflected, diffused, and refracted at both ends of the head, so most of the light does not go straight, and the light cannot be received by the light receiver, so the presence of droplets can be confirmed. However, when the central portion of the liquid droplet passes through the light projecting portion, most of the light is transmitted through the liquid droplet, and the light is received by the light receiver, so the presence of the liquid droplet cannot be confirmed. However, as shown in FIG. 4, the light receiving time detected while one droplet passes through the light projecting portion has a non-light receiving time (T 2, T 3) at each end of approximately 3 × 10 ^−3. It is a very short time from 5 seconds to 5 × 10 ⁻³ seconds, and the light receiving time (T 4) at the central portion is approximately 5 × 10 ⁻³ seconds to 9 × 10 ⁻³ seconds. In such a short-time light-shielding state, it is difficult to determine whether it is due to detection failure or liquid is not supplied, and there is a problem that the presence or absence of liquid cannot be reliably detected.

The above-mentioned phenomenon is remarkable when the transparency of the liquid is high and the particle size of the liquid droplet is small.

[0006]

[Problems to be solved by the device]

 An object of the present invention is to arrange a light transmitter and a light receiver linearly with a liquid sandwiched between them, project light onto the liquid by the light projector, and detect the presence or absence of the liquid based on the light reception state of the light. However, if the liquid is highly transparent, the light from the projector is not blocked by the liquid, and the light passes through the liquid and is received by the light receiver, so that it is not possible to reliably detect the presence or absence of the liquid. is there.

[0007]

[Means for Solving the Problems]

 In order to solve the problem, the light from the light projector is configured to be detected by the light receiver as reflected light from the liquid.

[0008]

【Example】

FIG. 1 is a front view showing one embodiment of the liquid detection device of the present invention, and FIG. 2 is a view taken along the line ZZ in FIG. In the figure, reference numeral 1 is a cylindrical case in which a liquid supply pipe 4 is connected to the upper part and a liquid sending pipe 5 is connected to the lower part, and the liquid is vertically dropped into a droplet or a continuous flow at a substantially central position. It is designed to run down. The case 1 may be configured so that the body portion, the lid portion, and the bottom portion can be divided, and the case 1 can be directly attached to the liquid receiving tank or the like. A light projector 2 is attached to the body of the case 1 and emits light toward the liquid. The light emitted from the projector 2 is preferably red light having a diameter of 1 mm and a wavelength of ⁶⁶⁰ × 10 ^-9 angstrom, but infrared rays can also be used. Reference numeral 3 denotes a light receiver attached to the case 1, which receives reflected light that is reflected, refracted, or diffused by impinging on the circumferential surface of the liquid that moves continuously or the spherical surface of the liquid that is intermittently supplied. Therefore, the light receiver 3 is arranged at an angle (θ) where the light from the light projector 2 can be received as reflected light by the liquid. 6 is an alarm lamp connected to the light receiver 3, and 7 is a buzzer. If the light receiver 3 does not receive light for a preset time, it is determined that an abnormality has occurred, an operation signal is sent to the lamp 6 to light it, and the buzzer 7 sounds. It is also possible to send an abnormal signal to a control device (not shown) so as to stop the entire machine to which the liquid sending pipe 5 is connected.

The case 1 may be made of glass or a transparent material such as synthetic resin, and the light emitter 2 and the light receiver 3 may be attached to the outside of the tube by a support or the like. .

In the above apparatus, when the liquid is intermittently supplied as a liquid droplet, it is necessary to pay attention to the setting of the non-light receiving time by the light receiver 3 so that the presence or absence of the liquid and the detection failure can be clearly determined. There is.

In the liquid detection device of the present invention, when the light from the light emitter 2 hits the liquid, it is reflected, refracted, and diffused even in the liquid body having high transparency, so that it is intermittently supplied in the form of liquid drops. As shown in FIG. 3, the entire liquid droplet can be received by the light receiver 3, and the light receiving time (T 1) is as long as 47 × 10 ⁻³ seconds, and the presence or absence of liquid can be reliably determined. .

Even when the liquid is supplied as a continuous flow, the amount of the reflected light received by the liquid is large, so the difference in the light received when the liquid supply is stopped becomes clear, and the presence or absence of the liquid can be reliably confirmed. Can be detected.

The outlet (D) of the liquid supply pipe 4 described above, the distance (H) from the outlet surface of the liquid supply pipe 4 to the detection position of the projector 2 and the light receiver 3, and the installation angle of the projector 2 and the light receiver 3 Regarding (θ), when the light projection diameter of the light projector 2 is 1 mm, when the liquid outlet diameter (D 2) of the liquid supply tube 4 becomes 1.4 mm or less, the liquid diameter and the droplet diameter are too small. If it is 8 mm or more, the diameter of the liquid or droplet is too large to reliably receive the reflected light, and 1.5 mm to 1. It is preferable to set it to 7 mm, and 1.6 mm is most preferable. Further, the distance (H) from the exit surface of the liquid supply pipe 4 to the detection positions of the light projector 2 and the light receiver 3 is 1. If it is 9 mm or less, a predetermined droplet is not formed when the liquid is supplied in a droplet state, and if it is 3.1 mm or more, the dropping speed of the droplet becomes too fast and the reflected light is reliably received. I can't. Therefore, the distance (H) is preferably set in the range of 2 mm to 3 mm. Furthermore, if the installation angle (θ) between the projector 2 and the photoreceiver 3 is 90 ° or less, or 150 ° or more, the amount of received light becomes extremely small and the liquid cannot be detected. Further, when the installation angle (θ) of the light projector 2 and the light receiver 3 was set to 100 ° to 130 °, it was possible to detect in almost all liquid supply states, and when it was 120 °, it was possible to surely detect. Therefore, the installation angle (θ) is preferably 100 ° to 130 °, and most preferably 120 °.

[0014]

[Effect of device]

 Since the liquid detection device of the present invention is configured so that the light from the projector is detected by the light receiver as reflected light by the liquid or diffused light, the presence or absence of the liquid can be reliably detected regardless of the transparency of the liquid. can do.

Further, a light receiver is arranged with respect to the light emitter so as to have a predetermined angle (θ) on the surface orthogonal to the moving direction of the liquid so that the light emitted from the light emitter can be received as reflected light by the liquid. With the provision, it is possible to reliably receive the reflected light from the liquid.

[Brief description of drawings]

FIG. 1 is a schematic front view showing a first embodiment of a liquid detection device of the present invention.

FIG. 2 is a view taken along the line ZZ in FIG.

FIG. 3 is a schematic view showing a light receiving state of liquid drops by the liquid detection device of the present invention.

FIG. 4 is a schematic diagram showing a light receiving state of liquid drops by a conventional liquid detection device.

[Explanation of symbols]

 1 Case 2 Emitter 3 Light Receiver 4 Liquid Supply Pipe 5 Liquid Delivery Pipe

Claims (2)

[Scope of utility model registration request] 1. A device for projecting light onto a liquid by a photoelectric sensor and detecting the presence or absence of the liquid based on the light receiving state thereof is configured so that light from the projector is detected by the light receiver as reflected light from the liquid. A characteristic fluid detection device. 2. A light receiver is arranged with respect to the light projector so as to have a predetermined angle (θ) so that light projected from the light projector can be received as reflected light by the liquid on a surface orthogonal to the moving direction of the liquid. The fluid detection device according to claim 1, wherein the fluid detection device is made.