JPH0337128B2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a flow meter for measuring the flow rate of a liquid.
In particular, the present invention relates to a flowmeter using a pipe, which is suitable for measuring liquids whose volume changes when subjected to pressure fluctuations, such as condensate generated in steam-using equipment.

The flow rate of the fluid can be determined by determining in advance the relationship between the liquid level upstream of the crossroads and the flow rate passing through the crossroads, measuring the liquid level upstream of the crossroads, and calculating from the above relationship.

The liquid level upstream of the river can be detected using a float. The liquid level can be converted into an electrical signal using a potentiometer or the like. This signal is received by a microcomputer system in which the relationship between the flow rate passing through the drain and the liquid level is written in the memory element ROM, and the flow rate can be calculated and displayed.

Prior Art The applicant has developed the above-mentioned flowmeter,
Patent Application No. 1983-167410 (Japanese Unexamined Patent Publication No. 61-45924)
proposed as. A cylindrical tube with a bottom is placed in the casing of the measuring device, which is formed to form a part of the flow path, and liquid is introduced into the casing of the measuring device. It flows out according to the liquid level in the cylinder. By communicating the upper space of the separator with the outer peripheral space and installing a float valve on the outlet side, a pressure difference is prevented from occurring before and after the separator. A partition wall member made of a thin cylinder is inserted vertically into the cylinder by penetrating the upper wall of the casing, and a float equipped with a magnet is slidably arranged around the partition wall member. A potentiometer is attached to the outside of the casing, a magnet is attached to its operating rod, and the potentiometer is inserted into the tube of the partition member.

In this case, when the flow rate is very small and the liquid level in the tube drops to near the bottom of the tube opening, the surface tension causes the liquid to stop passing through the tube, wait for the liquid level to rise, flow out, and stop again. Repeat the operation. In this way, the cross-type flowmeter has a lower limit in its measurement range.

In particular, in the flowmeter according to the above application, taking into account that the vertical movement of the float lags behind the actual liquid level fluctuation due to frictional resistance with the partition wall member, and that the upper limit of the measurement range is expanded, Since we used a shape where the width of the bar becomes narrower at the bottom, the effect of surface tension was large.

The technical problem of the present invention is to make it possible to measure the flow rate without being affected by surface tension even when the flow rate is very small and the liquid level in the tube drops to near the lower end of the tube.

Means for Solving the Problems The technical means of the present invention taken to solve the above-mentioned technical problems is to arrange a pipe with a pipe formed on the peripheral wall inside the casing, and introduce the liquid at the inlet. A liquid reservoir is formed above the secondary cylinder to allow the overflow liquid to flow down into the secondary cylinder, and the liquid reservoir and the inside of the secondary cylinder are connected with an inverted U-shaped pipe whose uppermost part is located below the overflow liquid level. A float is housed in the secondary cylinder, a potentiometer is connected to the float, a computer is connected to the potentiometer to calculate and display the flow rate, and the computer determines whether the liquid level in the secondary cylinder is below a predetermined level. Based on the relationship between the number of vertical movements of the float and the flow rate passing through the inverted U-shaped tube when the liquid level is below a predetermined level, the liquid level and the passage of the The present invention is characterized by having calculation means for calculating the flow rate from the relationship between the amounts.

Operation The liquid at the inlet is first introduced into the liquid reservoir. When the flow rate is minute, it passes through the inverted U-shaped tube and flows down into the cylinder. That is, when the liquid level in the liquid reservoir reaches near the top of the inverted U-shaped tube, outflow begins due to the siphon phenomenon, and when it drops below the opening end of the inverted U-shaped tube on the liquid reservoir side, outflow stops. Therefore, when the flow rate is minute, the liquid is temporarily collected in the liquid reservoir and then flows down to the stopper intermittently. A certain amount of liquid accumulated in the liquid reservoir between the lower end opening and the apex of the inverted U-shaped tube flows down every time the inverted U-shaped tube is operated. The higher the flow rate, the shorter the outflow interval.

When the float is lower than a predetermined position, it is determined that the flow is intermittently flowing down only through the inverted U-shaped tube. At this time, each time the liquid flows down intermittently, the liquid level in the cylinder shakes, causing the float to move up and down. Therefore, the vertical movement of this float and the inverted U
The relationship between the flow rate and the flow rate passing through the tube is determined in advance, and the vertical movement of the float is detected by its frequency and interval, and the flow rate is calculated and displayed.

The position of the float is detected by an electric signal converter such as a potentiometer, and the flow rate is calculated by a microcomputer system that stores the relationship between the flow rate passing through the inverted U-shaped tube and the vertical movement of the float in the memory element ROM. and display it.

Therefore, the minute flow rate can be accurately measured not from the amount passing through the tube but from the amount passing through the inverted U-shaped tube without being affected by surface tension.

Unique effects The present invention produces the following unique effects.

By reducing the cross-sectional area of the liquid reservoir, it is possible to reduce the amount of liquid that flows down through the inverted U-shaped tube in one operation. Reducing the amount of flow at one time improves the resolution of flow rate measurement, which improves measurement accuracy.

By combining it with the conventional method of detecting the liquid level from the relationship between the flow rate passing through the pipe and the liquid level in the pipe cylinder, calculating and displaying the flow rate, it is possible to
A flow meter with a wide flow rate measurement range can be obtained with a simple improvement such as adding a cross tube.

Embodiment An embodiment illustrating a specific example of the above technical means will be described (see FIG. 1).

A lid 2 is attached to the main body 1 with bolts (not shown) to constitute a casing of the measuring instrument. A substantially cylindrical space is formed inside the casing, and a cylindrical cylinder 3 with a bottom is attached thereto. An inlet 5 communicates with the inside of the barrel 3 through a cylindrical screen 4. A V-shaped opening, ie, a bulge 6, is opened in the peripheral wall of the bulge cylinder 3, and a communication hole 7 is opened in the upper part of the bulge 6. The inside and outside of the stopper tube 3 communicate through the stopper 6 and the communication hole 7, and the outside space communicates with the outlet 8 through a rising passage.

A cylindrical partition member 9 is located approximately in the center of the cylinder 3.
is placed vertically through the lid 2. The lower end of the partition member 9 is integrally closed and is fitted into a fixing member attached to the bottom wall of the main body 1 and the stopper tube 3. A hollow float 10 is arranged outside the partition member 9. A cylinder 11 that fits into the partition wall member 9 is attached along the central axis of the float 10, and an annular magnet 12 is attached to the outer periphery of the cylinder 11.
to be fixed. The float 10 is freely displaceable in the axial direction of the partition member 9 and rotatable in the circumferential direction.

On the lid 2, there is a heat insulating plate 13 and support members 14, 1.
5 are stacked on top of each other, the potentiometer 16 is fixed, and the cap 17 is covered. A microcomputer system (not shown) is coupled to the potentiometer 17.

The operating rod 18 of the potentiometer 16 is inserted into the partition member 9. At this time, a cylindrical magnet 19 is attached to the operating rod 18 so as to face the magnet 12 attached to the float 10 with the partition member 9 in between. One of the magnets 12 and 19 may be a magnetic material.

The magnetic joint made up of magnets 12 and 19 supports the operating rod 18 and requires a magnetic force sufficient to displace it.

A radially protruding vane 20 is provided on the outer surface of the float 10. The vane 20 is provided at a position where it is submerged in the liquid when the flow rate is minute.

An embankment member 21 having a substantially U-shaped cross section is attached from an inlet 5 to the upper side of the stopper cylinder 3 along the inner circumferential wall of the main body 1. The inner wall of the support member 21 extends approximately to a semicircumference, and an opening is provided at the tip in the tangential direction of the main body 1. The bank member 21 is provided with a partition wall 22 of about half the height, and a liquid reservoir 23 is formed inside. An inverted U-shaped tube 24 is attached to the liquid reservoir 23. Inverted U-shaped tube 2
The uppermost part of the float 4 is located below the upper end of the partition wall 22, and the opening on the side of the secondary tube 3 extends to the position of the blade 20 of the float 10 and opens in the tangential direction of the secondary tube 3. There is a small hole 2 at the top of the downward slope of the inverted U-shaped tube 24.
5 will be provided.

The liquid flowing in from the inlet 5 is first introduced into the liquid reservoir 23. When the flow rate is minute, the liquid is temporarily accumulated in the liquid reservoir 23. After the liquid level reaches near the top of the inverted U-shaped tube 24, it flows down from the inverted U-shaped tube into the drain cylinder 3 due to the siphon phenomenon, and the liquid level is lower than the opening end of the inverted U-shaped tube 24 on the liquid reservoir 23 side. It stops when it drops to . Every time the fluid flows down from the inverted U-shaped tube 24, the liquid level in the stopper tube 3 rises and falls, and the float 10 moves up and down.
The position of the liquid level due to the vertical movement of the float 10 is detected by a potentiometer 16. The rising position of the float is determined by the amount of liquid flowing down from the inverted U-shaped tube 24, so when it is below this position, the amount of liquid flowing down from the inverted U-shaped tube written in the memory element ROM of the microcomputer system is determined by the amount of liquid flowing down from the inverted U-shaped tube. From the relationship between the flow rate and the vertical movement of the float,
The flow rate is calculated and displayed based on the frequency and interval.

When the flow rate increases, the water flows continuously from the inverted U-shaped pipe 24 and even beyond the partition wall 22 of the embankment member 21.
It flows into the tube 3. At this time, the liquid level is higher than at the minute flow rate described above, so the flow rate is calculated and displayed from the relationship between the liquid level and the flow rate passing through the pipe 6.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a liquid flowmeter according to an embodiment of the present invention. 3: Seki tube, 5: Entrance, 6: Seki, 8: Exit,
9: Partition member, 10: Float, 12: Magnet, 1
6: Potentio meter, 18: Operation rod, 19:
Magnet, 23: Liquid reservoir, 24: Inverted U-shaped tube.

Claims (1)

[Claims] 1. A stop tube with a hole formed on the surrounding wall is placed in the casing, and a liquid reservoir is formed above the stop tube to introduce the liquid at the inlet and cause the overflow liquid to flow down into the stop tube, and the uppermost part is the overflow liquid. An inverted U-shaped tube located below the point connects the liquid reservoir and the inside of the stopper cylinder, houses a float inside the stopper cylinder, connects a potentiometer to the float, and calculates the flow rate to the potentiometer. The computer is connected to a computer that determines whether or not the liquid level in the cylinder is below a predetermined level, and when the liquid level is below a predetermined level, the number of up and down movements of the float and the inverted U-shaped tube are determined. 1. A liquid flowmeter comprising a calculation means for calculating the flow rate from the relationship between the liquid level and the amount of water passing through when the liquid level exceeds a predetermined liquid level.