KR20110082451A

KR20110082451A - Bubble sensor

Info

Publication number: KR20110082451A
Application number: KR1020100002441A
Authority: KR
Inventors: 강상욱
Original assignee: 강상욱
Priority date: 2010-01-11
Filing date: 2010-01-11
Publication date: 2011-07-19

Abstract

A bubble detection sensor is disclosed. Bubble detection sensor of the present invention, the light emitting diode is installed to face the inner space on the outer surface of the transparent material tube filled with a transparent liquid, such as water flow; A light receiving transistor installed on an outer surface of the tube so as to face the light emitting diode; An illuminance control resistor for adjusting illuminance of the light emitting diode; A sensitivity adjusting resistor for adjusting the sensitivity of the light receiving transistor; It includes a Schmitt trigger inverter (MC14584 series of chips) that receives a voltage applied to the point between the light-receiving transistor and the sensitivity control resistor to output a power supply voltage or OV. The bubble detection sensor of the present invention can detect the presence of bubbles in the tube as well as the presence of liquid in the tube. According to the present invention, compared to the conventional ultrasonic bubble detection sensor has a simple structure and circuit configuration can be easily manufactured and can also reduce the power consumption and manufacturing cost than conventional.

Description

Bubble Detection Sensor {Bubble Sensor}

The present invention relates to a bubble detection sensor, and more particularly, to a bubble detection sensor that can be easily manufactured by having a simpler structure and circuit configuration than the conventional one, and can also reduce power consumption and manufacturing cost more than conventionally. .

In general, in order to detect the presence of bubbles in the liquid inside the tube, an ultrasonic bubble detection sensor or the like is applied and used.

Ultrasonic bubble detection sensor uses the difference in the transmission characteristics according to the medium of the ultrasonic wave to install the ultrasonic transmitting and receiving sensors on both sides of the tube to determine the presence of liquid in the tube or the presence of bubbles in the flowing liquid.

However, such an ultrasonic bubble sensor has a disadvantage in that the circuit is complicated, the manufacturing cost is high, and the power consumption is high. In addition, the ultrasonic bubble sensor can be applied only to the tube having a soft material, there is a disadvantage that it is difficult to apply to the tube having a hard material.

An object of the present invention, by using the convex lens effect generated by the transparent liquid present inside the tube to have a simpler structure and circuit configuration than the conventional can be easily manufactured and also to reduce the power consumption than conventional bubble detection To provide a sensor.

According to the present invention, a light emitting diode is installed to face the inner space on the outer surface of the transparent material tube filled with a transparent liquid, such as water flows; A light receiving transistor installed on an outer surface of the tube so as to face the light emitting diode; An illuminance control resistor for adjusting illuminance of the light emitting diode; A sensitivity adjusting resistor for adjusting the sensitivity of the light receiving transistor; Schmitt-trigger inverter that receives the voltage applied between the light-receiving transistor and the sensitivity control resistor and outputs the power supply voltage in the presence of bubbles (or in the presence of liquid) and outputs the OV in the presence of bubbles (or in the presence of liquid). (Chip of MC14584 series) is achieved by the bubble detection sensor.

As described above, according to the bubble detection sensor of the present invention, it is possible to solve the disadvantages of the conventional ultrasonic bubble detection sensor, which is complicated in circuit, high in power consumption, and expensive in manufacturing.

1 is a front view schematically showing a bubble detection sensor according to an embodiment of the present invention.
2 is a state diagram showing the direction of refraction of light according to the presence or absence of bubbles (or the presence of liquid) in the bubble detection sensor according to an embodiment of the present invention.
3 is a circuit diagram for operating a bubble detection sensor according to an embodiment of the present invention.

In order to fully understand the present invention, the operational advantages of the present invention, and the objects achieved by the practice of the present invention, reference should be made to the accompanying drawings which illustrate preferred embodiments of the present invention and the contents described in the accompanying drawings.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Like reference numerals in the drawings denote like elements.

1 is a front view schematically showing a bubble detection sensor according to an embodiment of the present invention, Figure 2 is a state diagram showing the direction of refraction of light according to the presence or absence of bubbles in the bubble detection sensor according to an embodiment of the present invention 3 is a circuit diagram for operating a bubble detection sensor according to an embodiment of the present invention.

Bubble detection sensor according to an embodiment of the present invention can be used in various ways, such as intravenous infusion fluid injection device, injection device for various medical device automatic injection, sensor for chemical process control equipment, liquid level meta, vending machine, various liquid automatic control device have.

As shown in FIG. 1, the bubble detection sensor of the present invention includes a light emitting diode 4 installed on an outer surface of a transparent tube 2 through which a transparent liquid, such as water, flows toward the inner surface of the tube, and The light receiving transistor 6 is installed on the outer surface to face the light emitting diode 4, and the power is supplied through the two input terminals 30 and 32 of the sensor, and depending on the presence of air bubbles, the power supply voltage or 0V is applied through the sensor output terminal 34. It includes a circuit unit 50 for outputting a voltage of.

Here, the cross-sectional shape of the tube 2 is preferably formed in a circular shape for the implementation of the convex lens effect described later.

As shown in Fig. 2 (a), when there is a bubble-free liquid between the light emitting diodes 4 and the light receiving transistors 6 facing each other, the transparent liquid 8 filled inside the tube is a convex lens. The light 12 emitted from the light emitting diode 4 collects to the light receiving transistor 6. That is, as described above, since there is no bubble in the transparent liquid and the tube 2 has a circular cross section, a convex lens effect is generated.

On the other hand, as shown in FIG. 2 (b), when there are bubbles 10 between the light emitting diode 4 and the light receiving transistor 6 facing each other, the light 12 is directed to the light receiving transistor 6. Since it is not refracted, the above-described convex lens effect does not occur, so that the light 12 emitted from the light emitting diode 4 does not collect toward the light receiving transistor 6. Similarly, as shown in Fig. 2 (c), when there is no liquid between the light emitting diodes 4 and the light receiving transistors 6 facing each other, the above-described convex lens effect does not occur, and thus the light emitting diodes 4 The light 12 emitted from) does not collect toward the light receiving transistor 6.

In addition, because of the convex lens effect, the magnitude difference between the electrical signals (mainly voltages) measured by the light receiving transistors 6 becomes apparent depending on the presence or absence of the bubble 10 (or the presence or absence of the liquid 8). The bubble detection sensor has the advantage of not requiring a signal amplification circuit or noise canceling circuit.

If it is desired to detect the presence or absence of bubbles or liquids between the light emitting diodes 4 and the light receiving transistors 6 without using such a convex lens effect, since the bubbles and liquids are transparent, light reception is performed according to the presence or absence of bubbles or liquids. In order to distinguish the minute differences between the electrical signals generated in the transistors 6, a separate signal amplification circuit and a noise canceling circuit are required, resulting in a very complicated circuit implementation and a very high power consumption.

Therefore, since the bubble detection sensor of the present invention uses the convex lens effect, an implementation method for determining the presence of bubbles or liquids is very simple and power consumption is very low.

Hereinafter, the operation relationship of the bubble detection sensor according to an embodiment of the present invention will be described with reference to FIG.

First, the above-mentioned convex lens effect does not occur when bubbles exist in the liquid inside the tube or when the liquid itself does not exist. Therefore, the light emitted from the light emitting diode 4 cannot be collected by the light receiving transistor 6, and thus, at the point 60 between the light receiving transistor 6 and the light receiving transistor sensitivity adjusting resistor 26, an external input voltage (power supply voltage) A voltage lower than Vcc / 2 V, which is 1/2 of Vcc (30) V, is applied.

Here, the conversion of the voltage value applied to the point 60 is made through the illumination control resistor and the sensitivity control resistor which will be described later, and can be converted to other values.

Subsequently, the voltage value lower than the Vcc / 2 V is input to the input pin 1 of the Schmitt trigger inverter 40, which is a chip of the MC14584 series, and then converted to the voltage of Vcc V to the output pin 2 of the Schmitt trigger inverter 40. Is output. Therefore, Vout = Vcc V equal to the power supply voltage is output to the output terminal 34 of the bubble detection sensor.

On the other hand, when there is a bubble-free liquid between the light emitting diode 4 and the light receiving transistor 6, the above-described convex lens effect occurs. As a result, more light reaches the light-receiving transistor 6 than in the case described above, and at the point 60 between the light-receiving transistor 6 and the light-sensing transistor sensitivity control resistor 26, an external input voltage (power supply voltage) Vcc (30). A voltage higher than Vcc / 2 V, which is 1/2 of V, is applied.

Subsequently, the voltage value higher than Vcc / 2 V is inputted to the input pin 1 of the Schmitt trigger inverter 40 and then converted into a voltage of 0 V to the output pin 2 of the Schmitt trigger inverter 40, and outputs the same. Accordingly, Vout = 0 V is output to the output terminal 34 of the bubble detection sensor.

In FIG. 3, the illuminance control resistor 24 connected to the light emitting diode 4 is used to adjust the intensity (illuminance) of the light emitted from the light emitting diode 4 and to adjust the sensitivity connected to the light receiving transistor 6. The resistor 26 is provided to adjust the sensitivity of the light receiving transistor 6.

Meanwhile, power consumption of the bubble detection sensor may be minimized by appropriately adjusting the size of the illumination control resistor 24 and the size of the sensitivity control resistor 26. In addition, the size of the illumination control resistor 24 and the sensitivity control resistor 26 is properly tuned to the Vcc / 2 to the voltage input pin 1 of the Schmitt-trigger inverter when bubbles are present in the liquid or there is no liquid itself as described above. A voltage lower than V may be input, and if a bubble-free liquid is present, a voltage higher than Vcc / 2 V may be input to the voltage input pin 1 of the Schmitt-trigger inverter.

As described above, the present invention is not limited to the described embodiments, and various modifications and changes can be made without departing from the spirit and scope of the present invention, which will be apparent to those skilled in the art. Accordingly, such modifications or variations are intended to fall within the scope of the appended claims.

2: tube 4: light emitting diode
6: light receiving transistor 8: liquid
10: bubble 12: light (light trace)
24: illuminance adjustment resistance 26: sensitivity adjustment resistance
30: power supply (Vcc) 32: ground (GND)
34: Output voltage stage (Vout) 40: Schmitt trigger inverter
50: circuit part
60: point between light receiving transistor and sensitivity control resistor

Claims

A light emitting diode installed on an outer surface of the transparent tube made of a transparent material to face an inner space of the tube; And
And a light receiving transistor provided on an outer surface of the tube so as to face the light emitting diode.

The method of claim 1,
An illuminance control resistor for adjusting illuminance of the light emitting diode;
A sensitivity adjusting resistor for adjusting the sensitivity of the light receiving transistor; And
And a Schmitt trigger inverter having a Schmitt trigger function for receiving a voltage value applied to a point between the light receiving transistor and the sensitivity control resistor.

The method of claim 1,
When bubbles are present in the liquid inside the tube, light emitted from the light emitting diodes does not converge toward the light receiving transistor;
Bubble detection sensor, characterized in that for detecting the presence of bubbles by using a convex lens effect that the light emitted from the light emitting diode is collected toward the light receiving transistor when there is no bubble in the liquid inside the tube.