JP3172453U - Flow sensor - Google Patents

Abstract

A small, lightweight, and inexpensive sensor for detecting whether or not a very small amount of liquid (for example, 0.01 cc) has flowed is provided.
When a fluid flows through the tube 8, the conduit 4, and the tube 9 from the bottom to the top, the metal cylinder 6 is pushed up and moves upward. At that time, the photoelectric switch 5 detects the metal cylinder 6 and transmits a signal. When the flow of the fluid stops, the metal cylinder 6 sinks to its original position. Since the outer diameter of the metal cylinder 6 is larger than the inner diameter of the tubes 8 and 9, the metal cylinder 6 moves up and down in the pipeline 4 according to the flow without entering the tubes 8 and 9. An inner diameter 10 of the metal cylinder 6 serves as a fluid passage. If the inner diameter of the pipe 4 is 2.5 mm, the metal cylinder 6 is lifted by about 2 mm when the flow rate is 0.01 cc.
[Selection] Figure 1

Description

The present invention relates to a sensor that detects whether or not liquid has flowed through a pipe.

Conventionally, small, light, and inexpensive sensors have not been widely used to detect whether a very small amount of liquid (for example, 0.01 cc) has flowed. In a flow meter, a pressure gauge, or the like having a diaphragm configuration, a volume change due to the diaphragm absorbs the flow. A turbine type sensor cannot detect a very small amount of flow. In addition, the structure is complicated, bubbles may accumulate, absorb the flow, and disturb the flow.
Pumps that send extremely small amounts (for example, syringe pumps) are widely used with high accuracy, and in many cases, it is only necessary to detect whether the flow has occurred without measuring the flow rate itself.

Problems that the device tries to solve

Do not change volume for detection. A structure that does not accumulate air bubbles.

Means for solving the problem

In the present invention, a slidable cylindrical float (having a higher density than the fluid) is inserted into the conduit of the casing having the lower inlet and the upper outlet, and when there is no flow, it sinks to the lower inlet side. When fluid flows from the lower inlet, the cylindrical float is pushed by the flow and rises to the upper outlet. A detection sensor is placed outside the pipeline, and the presence or absence of flow is detected by the movement of the cylindrical float. When the flow disappears, the cylindrical float sinks again to the lower inlet side.

The flow sensor 1 includes a pipe joint 2 that forms an inlet at the bottom, a pipe joint 3 that forms an outlet at the top, a pipe 4 inside the center, a photoelectric switch 5 outside the pipe 4, and a slide inside the pipe 4. A movable metal cylinder 6 and a fixing nut 7 screwed with the screw extension 11 of the pipe joint 2 are arranged on the outer periphery of the lower part. The dimension of the inner diameter 10 of the metal cylinder 6 is determined so that a resistance is generated by a required fluid flow and the metal cylinder 6 is lifted. Tubes 8 and 9 are inserted into the pipe joint 2 and the pipe joint 3, respectively. The inner diameters of the tubes 8 and 9 are smaller than the outer diameter of the metal cylinder 6. The metal cylinder 6 is arranged at a position where the photoelectric switch 5 cannot detect when the lower end is stopped. The fixing nut 7 is used for fixing when the flow sensor 1 is attached to a bracket or the like. The main body 12 is made of a transparent material, and the photoelectric switch 5 detects light blocked when the metal cylinder 6 comes to the detection position.

Action

When the fluid flows through the tube 8, the pipe line 4, and the tube 9 from the bottom to the top, the metal cylinder 6 is pushed up and moves upward. At that time, the photoelectric switch 5 detects the metal cylinder 6 and transmits a signal. When the flow of the fluid stops, the metal cylinder 6 sinks to its original position. Since the outer diameter of the metal cylinder 6 is larger than the inner diameter of the tubes 8 and 9, the metal cylinder 6 moves up and down in the pipeline 4 according to the flow without entering the tubes 8 and 9. An inner diameter 10 of the metal cylinder 6 serves as a fluid passage. If the inner diameter of the pipe 4 is 2.5 mm, the metal cylinder 6 is lifted by about 2 mm when the flow rate is 0.01 cc.

effect

Since there is no volume change, it can be applied from a very small flow rate to a large flow rate by selecting dimensions.

Bubbles do not accumulate because fluid flows through the entire structure.

The structure is simple and can be provided at low cost.

The flow sensor 21 includes a pipe joint 22 that forms an inlet at the bottom, a pipe joint 23 that forms an outlet at the top, a pipe 24 inside the center, a proximity switch 25 outside the pipe 24, and a slide inside the pipe 24. A movable metal cylinder 26. The inner diameter 30 of the metal cylinder 26 is sized so as to be lifted by a resistance caused by a required fluid flow. Tubes 28 and 29 are inserted into the pipe joint 22 and the pipe joint 23, respectively. The metal cylinder 26 is arranged at a position that cannot be detected by the proximity switch 25 when the lower end is stopped.

Action

When the fluid flows through the tube 28, the conduit 24, and the tube 29 from the bottom to the top, the metal cylinder 26 is pushed up and moves upward. At that time, the proximity switch 25 detects the metal cylinder 26 and transmits a signal. When the fluid flow stops, the metal cylinder 26 sinks to its original position.

effect

The flow sensor 21 has the same effect as the flow sensor 1. By using the proximity switch 25 as the photoelectric switch 5, it can be made of an opaque material and can cope with a photo-curing resin such as a UV resin.

If the length of the metal cylinder 26 is accurately set, ON is detected at the upper end, OFF is detected at the lower end, the time is measured and converted into a flow rate, it can be applied not only to the presence or absence of flow but also to flow rate measurement and viscosity measurement.
Alternatively, the proximity switch 25 is installed in two stages or in multiple stages (can be easily installed in the gap 31), the passage time of the metal cylinder 26 between two points is measured and converted into flow rate and viscosity. It can also be used to measure viscosity.
The combination of the amplifier and the flow sensor 21 having a function of measuring the passing time and converting it into a required measurement amount is a convenient set for use. When the viscosity of the fluid, the flow range of the fluid, the gap between the cylindrical float and the pipe, the inner diameter of the cylindrical float, the weight of the cylindrical float, and the like are used as operational parameters of the amplifier, a more accurate required measurement amount can be detected.

If a spring is installed on the upper part of the metal cylinder 26 so that the metal cylinder 26 can be pressed, the installation posture can be freely set, and a cylinder of another material can be used instead of the metal cylinder.

Sectional view of Example 1 A sectional view of Example 1 Sectional drawing of Example 2 B sectional view of Example 2

1: Flow sensor 2: Pipe joint 3: Pipe joint 4: Pipe line 5: Photoelectric switch 6: Metal cylinder 7: Fixing nut 8: Tube 9: Tube

Claims (2)

An inlet was formed in the lower part, an outlet was formed in the upper part, a pipe line was formed in the center, and a detection switch and a slidable cylinder were placed outside the pipe line. A flow detection sensor characterized by. A combination comprising an amplifier having an arithmetic function for converting the amount of movement of the cylinder in the flow detection sensor according to claim 1 into a required measurement amount of fluid, and the flow detection sensor according to claim 1.

Images