JPS63222221A - Membrane flowmeter - Google Patents

Abstract

PURPOSE:To measure the flow rate of gas with good accuracy, by detecting the passage of the membrane composed of the soap solution moving in a pipe while carried by the gas flowing through the pipe by an electrode probe consisting of a pair of electrode needles. CONSTITUTION:Two electrode probes consisting of a pair of upper and lower electrode needles 12, 13 are provided to the side surface of a round pipe 3 so as to provide an interval therebetween. The leading end 12c of the bent part 12b of the upper electrode needle 12 protrudes into the round pipe from the inner surface thereof and, when the leading end surface 13a of the electrode needle 13 and the aforementioned leading end 12c are brought into contact with a membrane composed of a soap solution, both of them are brought to a continuity state to output an electric signal. Herein, when the air introduced into the round pipe 3 from the opening part at the lower end thereof rises through the round pipe 3, the membrane 9 also rises through the round pipe 3 with the rising of the air but, based on the time period from the point of time when the passage of the membrane 9 is detected by the electrode probe arranged at the lower position to the point of time when said passage is detected by the electrode probe arranged at the upper position, the flow rate of the air is calculated by an operation.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a membrane dipping liquid used for measuring gas flow rate, and in particular, to automatically detect passage through a membrane electrically to improve measurement accuracy.

Traditionally, gas flow m has been measured using a restrictor flowmeter such as an orifice,
Area flowmeters such as rotameters and volumetric t & coulometers are used. These flowmeters have a large pressure loss in the measuring section, and cannot be used if the pressure loss in the measuring section affects the characteristics of the device being measured.

Membrane flowmeters are provided as devices with low pressure loss in the measurement section. This membrane flow meter attaches a film made of soapy water or the like to a gas flow pipe, and the film moves along with the gas flowing into the pipe, thereby measuring the time it takes for the film to pass two measurement points. By measuring, the flow rate is measured.

The membrane flowmeter described above has the advantage of low pressure loss, but
There was a problem with measurement accuracy because the measurement of membrane passage at the measurement point was not automated. That is, conventionally, the passing of two measurement points is determined visually by a person, and the passing time is measured using a stopwatch or the like, so errors due to visual observation and errors when operating the stopwatch occur. For example, if the flow rate is fast, a small difference in the timing of pressing the stopwatch will result in a large error, and since the membrane has a convex shape due to surface tension, the passage time between the upper and lower ends of the membrane will be different. There is a difference in the amount of water, and when visually inspected, there are problems such as variations in judgment when passing through the membrane.

Furthermore, in the past, the production of the membrane and the attachment of the membrane to the tube were performed manually, which caused the problem that it was time-consuming.

Purpose of the Invention The present invention has been made in view of the above-mentioned problems, and provides a membrane flowmeter that automatically detects passage through a membrane at a measurement point, easily extracts the detection result as an electrical signal, and further includes:
By measuring the transit time with an electronic counter,
The aim is to improve measurement accuracy.

Furthermore, it is an object of the present invention to provide a membrane flowmeter that automates the production of a membrane and the attachment of the membrane to a gas flow pipe, and can obtain highly accurate measurement results without using human hands.

Structure of the Invention In order to achieve the above-mentioned object, the present invention includes a pipe for gas circulation,
A means for generating a film made of soap liquid or the like that moves in the pipe together with the circulating gas, and a means installed at two locations spaced apart along the axial direction of the pipe to automatically control the passage of the moving film. The present invention provides a membrane flowmeter characterized in that the membrane flowmeter is equipped with a sensor that detects the flow rate and outputs an electric signal, and is configured to automatically measure the flow rate via an arithmetic circuit based on the electric signal from the sensor.

Specifically, the above-mentioned gas distribution tube is installed vertically inside the main body provided with the gas inlet, and the lower end opening of the membrane tube is positioned at a predetermined distance from the bottom of the main body, and the gas introduced into the main body is is allowed to flow into the tube from the lower end opening, while a liquid for film production such as soap solution is stored at the bottom of the main body, and a ring for film production is supported between the nucleic acid and the tube opening by a driving means. The ring is arranged so that it can be raised and lowered freely, and when the ring is raised and exits from the liquid into the air, a film is generated, and the ring that holds the film is fitted onto the tube so that the film is attached to the inner circumferential surface of the opening of the tube. The above-mentioned sensors are installed at two measurement points in the tube in which the membrane rises with the gas, and each sensor consists of a point electrode probe consisting of a pair of electrode needles. A membrane flow rate characterized in that the tip of the electrode needle is shaped like a needle of several microns and is brought into point contact with the moving membrane, while the membrane contacting surface of the other electrode needle is a wide surface that is brought into contact with the membrane liquid on the inner peripheral surface of the tube. It provides a meter.

Hereinafter, the present invention will be explained in detail with reference to embodiments shown in the drawings.

As shown in Fig. 1, the device main body l has an airtight structure, -
An air inlet 2 is provided on the side, and a circular tube 3 for air circulation made of an acrylic tube or the like is installed vertically inside the main body l by passing through the upper surface la, and its lower end opening 3a is connected to the lower surface 1.
They are spaced apart from each other.b. Therefore, the air introduced from the air inlet 2 flows through the main body l as shown by the arrow in the figure.
The liquid is introduced into the circular tube 3 from the lower end opening 3a through the inside thereof, and is caused to rise inside the circular tube 3 along the axial direction and flow out.

A predetermined amount of soap solution 4 for film formation is supplied from the upper opening of the circular tube 3 and stored at the bottom of the main body l, and when the soap solution is supplied, the inner peripheral surface of the circular tube 3 is filled with the soap solution 4. It's getting wet. The lower end opening 3a of the circular tube 3 is arranged to face the liquid surface S of the soap solution 4 stored at the bottom of the main body 1 at a certain distance,
Between the circular tube opening 3a and the soap solution 4, a ring 5 for forming a film, which is one size larger than the outer diameter of the circular tube 3, is supported by a driving means and arranged to be able to rise and fall freely. That is, the lower end of the lifting rod 6 is connected to one side of the ring 5, and the upper end thereof is connected to the plunger 8 of the tsurenoid coil 7 installed in the main body I, and the solenoid coil 7 is energized. Accordingly, the ring 5 is raised and lowered from a lower end position indicated by a solid line in the drawing, where it is submerged in soap solution, to an upper end position, indicated by a chain line, where it is externally fitted into the cylinder 3. At that time, when the ring 5 rises, a film 9 is generated in the ring 5 when it comes out of the soap solution 4 into the air, and when the ring 5 is fitted onto the circular tube 3, the film 9 is formed on the inner surface of the opening 3a. 9 is attached.

In the circular tube 3, sensors consisting of an upstream point electrode probe 10A and a downstream point electrode probe IOB are installed at regular intervals on the upper part of the tube 3 projecting outward from the main body 1 to detect the passage of @9. There is.

The structure of these point electrode probes IOA and IOH is as shown in FIG. 2, and a probe unit 11 is fixed to the outer surface of the circular tube 3 so as to surround a measurement hole 3b formed in the side surface of the circular tube. A pair of upper and lower electrode needles 12 and 13 are attached to the probe unit body 11 so as to protrude into the measurement hole 3b, and when these pair of electrode needles 12 and 13 come into contact with the soap solution 4, they conduct and generate an electrical signal. I am trying to output it.

The pair of upper and lower electrode needles 12 and 13 described above have the shape shown in FIG. However, the tip 12c of the bent portion 12b is made to protrude inward from the inner surface of the circular tube 3 by about 2 mm. The electrode needle 12 is made of a conductive material such as platinum, sass, or inconel, and has a conductive material of approximately 0.
, is formed to a thickness of about 1 am, and the bending part tip 1
The entire surface except for the tip 2c is coated with an insulating material, and the tip 12c, which is several microns in size, is set to become conductive only when it comes into contact with the film 9 of the soap solution 4.

On the other hand, the lower electrode needle 13 is linear, and the upper electrode needle 12
The diameter is larger than that of the probe unit body 11.
The wide end face 13a is located at the inner surface of the circular tube 3. Since the inner circumferential surface of the circular tube 3 is pre-wetted with the soap solution 4 as described above, the tip end surface 13a of the electrode needle 13 is always in contact with the soap solution.

Therefore, in the point electrode probe l0AS IOB,
When the membrane 9 rises and the tip 12c of the electrode needle 12 comes into contact with the membrane 9, an electric circuit is closed and an electric signal passing through the membrane is output.

The point electrode probes IOA and IOB are computer 15
are connected to the computer 1, and each membrane passage detection signal is sent to the computer 1.
5, a counter (not shown) installed in the computer 15 measures the time required to pass between the point electrode probes IOA and IOB, and an arithmetic circuit (not shown) measures the time required to pass between the point electrode probes IOA and IOB. Internal diameter and point electrode probe IOA and 10
The flow rate is measured from the distance 12p between 8 and the like.

Next, the measurement operation by the automatic membrane flowmeter described above will be explained.

The solenoid coil 7 is energized and the plunger 8 is raised to take the ring 5 out of the soap solution 4 into the air. At that time, a film 9 is generated inside the ring 5, and the ring 5 is further raised with the film 9 held. By fitting the circular pipe 3 externally into the circular pipe 3,
A film 9 is attached to the inner surface of the lower end opening 3a. Next, when air is introduced into the main body 1 through the air introduction port 2, the air flows into the circular tube 3 through the lower end opening 3a and rises inside the circular tube 3.

The membrane 9 attached to the opening 3a is pushed by the air and rises inside the circular tube 3 as the air rises. When the membrane 9 moves up inside the circular tube 3, first, the upstream point electrode probe IOA installed at the lower position detects the passage, and then the downstream point electrode probe IOB installed at the upper position detects the passage of the membrane 9. To detect. This detection result is inputted to the computer 15 as an electric signal, the time t required for the membrane 9 to pass between the two points is pole probes 1°A and 103 is counted by a counter, and the air flow rate Q is calculated by an arithmetic circuit as follows. It is calculated by the formula. However, as mentioned above, D is the inner diameter of the circular tube 3, I2
p is the distance between the point electrode probe IOA and 1013.

Q=πD”Qp/4 In the above-mentioned membrane-separated needle, the point electrode probe IOA.

The detection signal obtained from 10B is as shown in FIG. 4 (AXB), and (A) and CB) are shown on different time axes. As shown in (A), the output signal when passing through the membrane has a sharp rising edge and has an output greater than the noise level, and is therefore easily detectable. Further, (B) shows the calculation of the rise time constant tp of the point electrode, and in the experimental example according to this embodiment, the rise time constant was 73±24 μs.

The reason why the output signal is large and has a sharp rise as described above is because in the point electrode probes 10A and 1OB, the contact point of one electrode needle 12 is made at an acute angle to make point contact. By obtaining the signal, measurement errors can be reduced, and as a result, measurement accuracy can be increased. In addition, in order to make it possible to increase the measured flow rate without reducing measurement accuracy, we installed a large number of point electrode probes in advance at positions with different Qp sizes.
You can also use these separately.

(Experiment example) Using circular pipe 3 with inner diameters of 50 mn+ and 26 ma+, Q=
2xlO-' to 7xl O-'m'/s, Qp
Flow rate measurement was performed for =150mffi. As a result, for a circular pipe with an inner diameter of 5011Ill, the inner diameter was 2
The error for the 6th instar round tube was less than ±0.8%.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and the detection of membrane passage at a measurement point may be performed using an optical sensor consisting of a light emitter and a light receiver instead of a sensor using a point electrode. Any device that can automatically detect passing, extract it as an electrical signal, and count the time required to pass a predetermined distance can be adopted as appropriate.

Further, the liquid for forming the film 9 is not limited to soap solution, and any liquid that can form a film with the required stable liquid may be used.

Effects of the Invention As is clear from the above explanation, the membrane flowmeter according to the present invention can automatically detect passage through the membrane at two measurement points and extract it as an electrical signal. It is possible to measure the time required to travel a predetermined distance by counting the time difference using electrical signals, and automatically measure the flow rate from that time.This greatly improves measurement accuracy compared to conventional visual measurements. can be improved. In addition, since the detection signal for passing through the membrane is a large signal with a sharp rise, it can be easily detected.
Since there is less time delay and an electrical output corresponding to the flow rate can be obtained, measurement accuracy is further improved. In addition, since this membrane flowmeter only detects the movement of the membrane in the measuring section,
Pressure loss in the measuring section can be prevented from affecting the characteristics of the device being measured.

What's more, Shita Ichida's biggest problem! Since the entire process is automated, including the process of attaching the sukewarashi to the air flow pipe, the flow rate can be measured without manual intervention, making it suitable for use in various automated systems. It has various advantages such as being able to

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing an embodiment of the present invention, FIG. 2 (1) is a horizontal cross-sectional view showing details of a point electrode probe, and FIG.
) is a vertical sectional view, FIG. 3 is an enlarged view showing the contact state between the electrode needle and the membrane, and FIG. 4 (D ([[) is a line diagram showing details of the rising part of the point electrode signal. !・Main body, 2. Air inlet, 3. Circular pipe,
4. Soap solution, 5. Ring, 7. Solenoid coil, 9.
Membrane, 10A...upstream point electrode probe, 10r3...downstream point electrode probe, 11...probe unit body, ! 2.13...electrode needle, 15...computer.

Claims (3)

[Claims] (1) A means for generating a film made of a soap solution or the like that moves inside the pipe together with the circulating gas, and a means installed in the pipe for gas distribution at two locations spaced apart along the axial direction of the pipe. ,
A membrane flowmeter comprising a sensor that automatically detects the passage of the moving membrane and outputs an electrical signal, and is configured to automatically measure the flow rate through an arithmetic circuit using the electrical signal from the sensor. . (2) In the membrane flowmeter according to claim (1),
The sensors installed at the two measurement points on the tube are each composed of a point electrode probe consisting of a pair of electrode needles, and one electrode needle of each point electrode probe has a needle-like tip of several microns and is attached to a moving membrane. A membrane flowmeter characterized in that the membrane contacting surface of the other electrode needle is made into a wide surface and is brought into contact with the membrane liquid on the inner circumferential surface of the tube. (3) In the membrane flowmeter according to claim (1),
The above-mentioned gas distribution pipe is vertically installed inside the main body provided with the gas inlet, and the lower end opening of the pipe is positioned at a predetermined distance from the bottom of the main body, so that the gas introduced into the main body can flow into the pipe. While the flow is allowed to flow from the lower end opening, a liquid for forming a film such as soap solution is stored at the bottom of the main body, and a ring for forming a film is supported between the liquid and the pipe opening by a driving means, so that it can be raised and lowered freely. Place it in
A membrane flow rate characterized by having a structure in which a film is generated when the ring rises and exits from the liquid into the air, and the film is attached to the inner peripheral surface of the opening of the pipe by fitting the ring holding the film onto the pipe. Total.