JPS6344150A - Bubble detector for solution infusion pipe - Google Patents

Abstract

PURPOSE:To enable the detection of bubbles in a liquid at a high accuracy, by irradiating a cylindrical liquid conveying pipe with two light sources of monochoric light or the like. CONSTITUTION:Two light sources 2 and 2' are arranged as opposed on the right and left of a solution infusion pipe 4 for a fluorocarbon resin in a yoke 3 and a light receiving element 1 is provided at the right angle to the pipe 4 on a plane containing the light sources 2 and 2'. The light sources 2 and 2' herein used are preferably monochroic light or the like with the wavelength of about 300-1,100nm from a light emitting diode which generates visible light or the like and the yoke 3 is made of a black synthetic resin. A chemical aqueous solution is made to flow into the pipe 4, which then is, irradiated with the light sources 2 and 2'. At this point, as bubbles existing in the chemical aqueous solution passes through a light irradiation portion in the pipe 4, the inner wall surface of the pipe 4 is made reflective and refractive with air contacting the surface. Thus, being circular arc in the shape, the inner wall surface of the pipe 4 causes a scattered reflection, yet a part of the transmission light is made to irradiate the element 1 by reflected and refraction to actuate it 1 thereby enabling detection of bubbles with an increase in the output of the element 1.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a device for detecting air bubbles in a liquid flowing through an infusion tube.
In particular, it relates to a simple and highly accurate bubble detection device.

(Prior art) Conventionally, when injecting fluid into a patient, if air bubbles are present in the drug solution, the air can cause blood clots, which can be extremely dangerous to the patient, so care has been taken to avoid injecting air in the drug solution. It is extremely important to ensure that For this reason, various detection devices have been developed to detect air bubbles in infusion tubes along with devices such as infusion pumps, but these devices are difficult to mechanically adjust, so their operation is generally unreliable. . There is also a device that uses a light receiving element to detect the presence of bubbles in a liquid by using the difference between the refractive index of the liquid and the refractive index of the air, or by using transmitted light. For example, in U.S. Pat. No. 4,366,384, one light source and two light receiving elements are installed, and one light receiving element detects reflected light and the other light receiving element senses transmitted light to detect bubbles. ,1
Adjustment is difficult because reflected light and transmitted light are sensed with one light source, and Japanese Patent Application Laid-Open No. 184843/1984 illuminates the flat part of the infusion tube with one light source and uses the reflection characteristics of the flat surface to eliminate air bubbles. However, it is extremely difficult to provide such a flat surface on an infusion tube.

(Problems to be Solved) As a result of various studies to improve the above-mentioned drawbacks, the present inventors found that by using a light source consisting of two monochromatic or semi-monochromatic lights, even when using a normal infusion tube, It was discovered that a simple and highly accurate bubble detecting device could be obtained, and the present invention was completed.An object of the present invention is to provide a simple and highly accurate bubble detecting device.

(Means for Solving the Problems) That is, the present invention provides two iIL color lights at symmetrical positions opposite to each other on the left and right sides of a transparent or translucent cylindrical infusion tube in a horizontal plane. Alternatively, there is a bubble detection device in an infusion tube, characterized in that a light source of semi-monochromatic light is installed, and a light-receiving element that extends from the infusion tube and receives light from the light source is provided in a plane that includes the light source. . However, in the present invention, the infusion tube is illuminated by a 211M light source, but when a bubble passes on the optical path between these two light sources, the refractive index changes, and the light receiving element detects this and detects the bubble. It detects. In the present invention, it is necessary to install two light sources at opposite positions on the left and right sides of the infusion tube, and if there is only one light source, even if bubbles pass through the tube, the reflected light toward the light receiving element will not be reflected. In the case of the two light beams described above, the intensity is not strong, and furthermore, depending on the passage position of the bubble in the tube, the amount of reflected light towards the light receiving element is extremely small.As a result, the output signal of the light receiving element is at a low level and the bubble detection ability is low. 6 Furthermore, since the cross section of the infusion tube is circular, the irradiated light causes diffuse reflection on the outer and inner wall surfaces of the tube, but in the present invention, because of the two light sources, the irradiated light is attenuated to the extent that it affects bubble detection. Since most of the reflected light is absorbed by the yoke,
It has almost no effect on bubble detection. The material for the infusion tube used in the present invention may be any commonly used material, such as fluororesin, polyvinyl chloride resin, methacrylic resin, polyethylene resin, silicone rubber, or the like. The light source used for bubble detection is monochromatic or semi-monochromatic light with a wave length of 300 to 1100 NO+, and the light receiving element of the light receiving section has a wavelength of 300 to 1100 NO+.
It detects n monochromatic or semi-monochromatic light. Although the optical path between the light sources in the present invention does not necessarily have to be perpendicular to the infusion tube, it is preferable to do so in view of the intensity of the light. Alternatively, a plurality of them may be used as necessary.

The invention will be explained with reference to the drawings. FIG. 1 is a schematic diagram of the bubble detection device of the present invention, and FIG. 2 is a plan sectional view thereof. In the drawing, two light sources 2.2' are provided on the left and right sides of the infusion tube 4, facing each other. As a light source, a light generating diode that generates visible light or infrared light has a wavelength of 300 to 1l10.
It is preferable to use 0n monochromatic or semi-monochromatic light, and the light receiving element 1 is provided in a direction perpendicular to the infusion tube on a plane containing the light sources 2, 2'. Then, the light source and light receiving element are installed in the yoke 3 that holds the infusion tube while maintaining the respective positional relationships between the infusion tube, the light source, and the light receiving element as described above. The yoke 3 is made of a black synthetic resin that does not transmit disturbance light. Note that it is desirable to bias the light source so that it is not affected by disturbance light as much as possible.

Next, the operation of the illustrated device will be described.

The aqueous drug solution flows inside the infusion tube body 4, and the infusion tube is irradiated with light 'g2 and 2''.The irradiated light is slightly reflected on the outer wall of the infusion tube, but most of it passes through the infusion tube. When an aqueous drug solution is present in the infusion tube, the inner wall surface is in contact with the aqueous solution, so the inner wall surface has virtually no reflective or refractive properties, so light is transmitted to the opposite side or is absorbed by the liquid. It is absorbed and the light-receiving element 1 does not substantially operate.Although some of the irradiated light may be reflected and refracted by the inner and outer wall surfaces and illuminate the light-receiving element 1, the amount of this light is extremely small, so the light-receiving element 1 does not operate. The output signal of is small and can be ignored. When air bubbles exist in the aqueous chemical solution and the bubbles pass through the light irradiated part of the tube, the air comes into contact with the inner wall surface of the tube body, making that surface reflective and refractive. .

However, since the inner wall surface of the tube is arcuate, diffuse reflection occurs, but a portion of the transmitted light inevitably irradiates the light receiving element 1 by reflection and refraction. Furthermore, reflection and refraction also occur on the interface between air and liquid. As a result, most of the transmitted light operates the light receiving element by reflection and refraction, resulting in a significant increase in the output of the light receiving element.

(Effects of the Invention) As described above, the present invention detects air bubbles in a liquid with high precision using an extremely simple device in which a conventionally used cylindrical infusion tube is irradiated with two monochromatic light sources or oxcart color light sources. It can be detected, and its operation and adjustment are easier than conventional ones.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram for explaining the present invention in detail,
FIG. 2 is a plan sectional view thereof.

Claims (1)

[Claims] Two monochromatic or semi-monochromatic light sources are installed at symmetrical positions facing each other on the left and right sides of the transparent or translucent cylindrical infusion tube on a horizontal plane, and are perpendicular to the infusion tube. In addition, when the gas in the infusion tube exists in a position that does not receive direct light from the light source within a plane that includes the light source, the inner surface of the infusion tube and the interface between the gas and the infusion have optical reflectivity. A bubble detection device in an infusion tube, characterized by being provided with a light-receiving element that detects the presence of air bubbles in an infusion tube.