JPS601377Y2 - fluid flow meter - Google Patents

Description

[Detailed description of the invention] This invention relates to an impeller-type fluid flowmeter that rotates an impeller using the energy of the fluid and measures the flow rate of the fluid by the number of revolutions of the impeller.The purpose of this invention is to Our objective is to provide flowmeters with high accuracy, long life, and high practical value.

Conventionally, this type of fluid flow meter rotates an impeller that is rotated by the energy of the fluid to be measured in proportion to the flow rate of the fluid, and the rotation of the impeller is transmitted to a pointer or the like through a transmission device consisting of a group of gears. The number drum is rotated to display the total flow rate.

However, in this conventional fluid flow meter, since the fluid flow rate indication due to the rotation of the impeller is transmitted by a transmission device consisting of a group of gears, the following problems occur.

That is, when the flow rate of the fluid is small, the energy of the fluid acting on the impeller is small and the impeller cannot rotate due to the meshing resistance of the gear EY of the transmission device, so the dead flow rate is large and the flow rate sensitivity is low. not good.

However, the structure is complicated, the mold is large, and the price is relatively high.

Furthermore, nearly 80% of failures in this type of fluid flow meter are due to failure of gears in the transmission device, which poses a problem in durability.

Additionally, when attaching a remote meter to a conventional flowmeter, a readout rotary wreath or switch was attached to the mechanical integration mechanism.

However, because it has a large number of contacts, the sensitivity and reliability are poor.
Furthermore, it has the disadvantage of being complicated in structure, large in size, and expensive.

In addition, since the minimum unit of this remote meter's transmitting and receiving device is the transaction unit (/e) or one-tenth thereof (in 100), it is not possible to check whether the meter is rotating or not in a short time. There was a problem that there was no water leakage, and the leakage could not be detected.

Furthermore, in order to improve the flow meter with this mechanical configuration, a magnet was installed at the upper end of the impeller installed in the fluid passage, and a magnetic detection circuit was installed opposite to this, so that the magnetic detection circuit could be activated in accordance with the rotation of the impeller. The applicant has previously filed an application for a device that counts the flow rate by counting the pulses generated by the flow using an electronic circuit counter.

However, this device does not allow the fluid to flow backwards or cause the impeller to vibrate.
However, even when the pulse train is generated at the same time, all of the pulses are counted in the forward rotation direction, resulting in an error.

This idea was developed in view of the drawbacks of the conventional impeller type fluid flow meter with the above-mentioned mechanical configuration and electronic circuit configuration, and improved and eliminated them.
The purpose is to provide a flowmeter with a simple mechanical structure, high precision, and long life with excellent practical performance.

An example of the configuration of this invention shown in the drawings will be described below.

The fluid flowmeter of the embodiment shown in FIG. The lid 3 is attached.

An impeller 4 that rotates in proportion to the flow rate of fluid flowing into and out of the lower casing 2 is rotatably mounted on the lower casing 2, and a magnet 5 is attached to the upper end of the impeller 4.

Inside the upper casing 1, there are an electronic circuit 6 for counting, two magnetic resistance elements 7a and 7b arranged facing the magnet 5 and shifted in position, and a lithium battery 8, which is connected to M3 and closes when M3 is opened. A switch 9 and a liquid crystal display panel 10 are built-in.

The liquid crystal display panel 10 has integrated value display numbers 11 and a pilot 12 that blinks as the impeller 4 rotates.

Also, in the internal configuration of the electronic circuit 6, 13 is a lithium battery 8.
14 is a voltage drop detection circuit that detects a voltage drop in the power supply circuit 13 and issues four alarms several evenings before it completely stops functioning due to battery life. , 15a, 15b are magnetoresistive elements 7a, respectively.
, 7b, a differential amplification and waveform shaping circuit receives the outputs of the magnetoresistive elements 7a and 7b generated by the magnet 5 crossing them, amplifies the output, and shapes the waveform into a single pulse, 16
The rotation direction of the impeller 4 is determined from the phase difference between the output pulses of the differential amplification and waveform shaping circuits 15a and 15b, and the counting pulses are distinguished as positive and negative, and the same pulses caused by vibrations of the sitting impeller 4 are determined. a forward/reverse discrimination circuit that does not count continuous pulses from the magnetoresistive element 15a or 15b as abnormal pulses; 17;
18 is a reversible preset counter that counts based on the output of the forward/reverse discrimination circuit; 18 is a digital setting circuit that presets the preset counter to a predetermined digital value; 19 is for electrically correcting negative instrumental error in the minute flow rate range; 20 is a reversible total counter; 21 is a liquid crystal drive circuit; and 22 is a differential amplification and waveform shaping circuit 15a. , Is there a magnetoresistive element to 15b? In order to reduce the current consumption of at7b, a crystal oscillation circuit provides a clock signal of a reference frequency for modulation, and provides a clock signal of the reference frequency to the instrumental error correction circuit 19, liquid crystal drive circuit 21, etc.; Serial conversion and buffer circuit that converts into data and outputs it to the outside, 2
4 is a gate circuit that receives the high level output of the switch 9 that closes when the lid 3 is opened and sends the output of the liquid crystal drive circuit 21 to the liquid crystal display panel 10; 25 is a transmission line for remote meter reading; and 26 is a remote meter reading receiving board. be.

The operation of this device is as follows.

When fluid flows in and out of the fluid passage in the lower casing, the impeller 4 rotates.

Then, the magnet 5 rotates and the magnetic field it forms rotates.

Magnetoresistive element? Since magnets a and 7b are disposed facing the magnet 5 and shifted in position, these are detected as phase-shifted changes, respectively.

This amount of change is determined by the differential amplification and waveform shaping circuit 15at, respectively.
15b, the signal is converted into a phase-shifted pulse train.

The forward/reverse determining circuit 16 uses the phase shift of the transmitted pulse train to determine forward/reverse.

At this time, continuous pulses from the same magnetoresistive element caused by impeller vibration are determined to be abnormal pulses and are not counted.

From the forward/reverse discrimination circuit 16, count pulses for forward rotation and count pulses for reverse rotation are input to the preset counter 17.

A correction value is given to the preset counter 17 at regular intervals from a digital setting circuit 18, which is given a correction amount by an instrumental error correction circuit 19, to automatically correct the negative instrumental error that occurs in the minute flow rate range.

The preset counter 17 provides the forward/reverse rotation amount and the correction amount to the total counter 20, and the total counter 20 counts the integrated value of the flow rate.

This value is an extremely highly accurate flow rate count value that automatically subtracts the negative instrumental error in the fluid back flow rate and minute flow rate range.

This flow rate count value is given to the liquid crystal drive circuit 21.

The liquid crystal drive circuit 21 causes the liquid crystal display panel 10 to perform a display operation via the gate circuit 24, but the gate circuit 24 becomes conductive only when the switch 9 interlocked with the lid 3 is closed.

Therefore, only when the lid 3 is opened, the liquid crystal display panel 10 displays the flow rate counted by the total counter 20.

In addition, on the liquid crystal display panel 10, the flow rate count value is displayed as the integrated value display number 11, and at the same time, if the fluid is flowing and the impeller 4 is rotating, the LED pilot 12 will blink to let you know this. be able to.

In this way, when the lid 3 is closed, the liquid crystal display panel 10
is not driven, and almost no power is supplied from the power supply circuit 13 to the liquid crystal drive circuit 21, so that the battery life can be extended.

Further, the liquid crystal drive circuit 21 outputs the flow rate count value to the serial conversion and buffer circuit 23, which converts it into serial data and outputs it to the outside.

Therefore, when reading the flow rate by remote operation externally, the impeller 4 is rotated by the flow rate count value and fluid flowing through the remote meter reading receiving board 26 connected via the transmission line 25 for remote meter reading. You can read the LED pilot indicating that the lid 3 is open in the same way as when you open the lid 3 and see it.

Note that in these electronic circuits 6, the crystal oscillation circuit 22
Obtain an extremely accurate reference frequency clock signal using
Since it is supplied to each circuit, the accuracy of the device can be extremely high.

As explained above, this invention consists of a lower casing rotatably provided with an impeller that rotates in proportion to the flow rate of fluid and has a magnet at its upper end, and a battery-powered impeller that is placed opposite the magnet. The upper casing is isolated from the lower casing, and the upper casing is isolated from the lower casing. In the meter, the counting electronic circuit is comprised of a voltage drop detection circuit that detects voltage drops due to battery exhaustion, etc., and issues an alarm before the battery completely stops functioning due to battery life, and two magnetic resistance elements. The output pulses from the differential amplification and waveform shaping circuit amplify each output and shape the waveform into a single pulse, and determine whether the rotational direction of the impeller is normal or reverse, and a reversible preset counter is added or subtracted to drive the impeller. A forward/reverse discrimination circuit that does not count the continuous pulses from the magnetoresistive element, an instrumental error correction circuit that corrects negative instrumental errors in the minute flow range from the count value of the reversible preset counter, and a reversible type that corrects instrumental errors. A total counter that integrates the count value from the preset counter, a liquid crystal drive circuit that outputs drive output to the liquid crystal display panel based on the integrated value of the total counter, and a differential amplification and waveform shaping circuit that use magnetoresistive elements to reduce current consumption. A crystal oscillator circuit provides a reference frequency clock signal for modulation, and also provides a reference frequency clock signal to the instrumental error correction circuit and liquid crystal drive circuit. There is also a switch that operates the LCD panel using the drive output from the LCD drive circuit and disables the display panel when the lid is closed. It consists of a pilot display mechanism that flashes in synchronization with the rotation of the meter, and a serial conversion and buffer circuit that converts the output of the LCD drive circuit into serial data and sends it to the remote meter reading receiving board via the transmission line for remote meter reading. Since the remote meter reading receiver is also equipped with a pilot display mechanism that flashes in synchronization with the rotation of the impeller, the following effects can be achieved.

That is, since the necessity of battery replacement is notified before the battery life runs out, there is no problem of continuing to use the device without knowing that the counting function has stopped.

In addition, in addition to determining the forward and reverse rotation directions of the impeller and adding and subtracting them using a reversible preset counter, we also prevent the counting electronic circuit from erroneously counting due to factors other than rotation, such as vibration of the impeller.
Since the continuous pulses from one of the magnetoresistive elements are prevented by not being counted, the amount used can be accurately counted.

Moreover, since the negative instrumental error at minute flow rates was corrected,
The proportional relationship between the flow rate and the counted value can be maintained accurately down to the minute flow rate range, and counting accuracy and reliability can be improved.

In addition, the total counter allows you to easily
The integrated value can be stored and retained.

The crystal oscillator circuit provides high accuracy, and the LCD panel is activated only when reading the meter to extend battery life.Furthermore, the rotation of the impeller is also displayed as a pilot.
The operation of the flowmeter can be checked in a short time, and remote meter reading is also possible.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. 1... Upper casing, 2... Lower casing, 3
... Lid, 4... Impeller, 5... Magnet, 6.
...Electronic circuit? a, 7b... Magnetoresistive element, 8...
・Remote meter reading, 9... Switch, 10... Liquid crystal display panel, 14... Voltage drop detection circuit, 15a, 15b.
...Differential amplification and waveform shaping circuit, 16... Forward/reverse discrimination circuit, 17... Preset counter, 18... Digital setting circuit, 19... Instrumental error correction circuit, 20... Total counter, 21...Liquid crystal drive circuit, 22...
- Crystal oscillation circuit, 23... Serial conversion and buffer circuit, 24... Gate circuit, 25... Transmission line for remote meter reading, 26... Remote meter reading receiving board.

Claims (1)

[Claims for Utility Model Registration] A lower casing rotatably provided with an impeller that rotates in proportion to the flow rate of fluid and has a magnet at the upper end, and a battery-powered impeller, which is disposed opposite to the magnet. A fluid flowmeter comprising an upper casing isolated from the lower casing, and housing a counting electronic circuit that integrates and displays the fluid flow rate from the impeller rotation speed on a liquid crystal display panel via two magnetoresistive elements. In the electronic circuit for counting,
There is a voltage drop detection circuit that detects voltage drops due to battery exhaustion, etc., and issues an alarm a certain period before the battery stops functioning completely due to battery life, and a voltage drop detection circuit that amplifies the outputs of two magnetoresistive elements and converts each waveform into a single pulse. The output pulse from the differential amplification and waveform shaping circuit determines whether the rotation direction of the impeller is normal or reverse, and drives a reversible preset counter to add or subtract, and the continuous pulses from one magnetoresistive element are not counted. a forward/reverse discrimination circuit, which corrects the negative instrumental error in the minute flow range from the count value of the reversible preset counter, and a total counter that integrates the count value from the reversible preset counter that has been corrected for the instrumental error. , a liquid crystal drive circuit that outputs drive output to the liquid crystal display panel based on the integrated value of the total counter, and a differential amplifier and waveform shaping circuit that uses a reference frequency clock signal for modulation to reduce the current consumption of the magnetoresistive element. and a crystal oscillator circuit that provides a reference frequency clock signal to the instrumental error correction circuit and the liquid crystal drive circuit, and a liquid crystal display using the drive output from the liquid crystal drive circuit only when the lid provided on the top of the upper casing is opened. A switch that activates the display panel and disables the display panel when the lid is closed, and a pilot display mechanism that is installed in a part of the liquid crystal display panel and flashes in synchronization with the rotation of the impeller only when the lid is opened. It consists of a serial conversion and buffer circuit that converts the output of the liquid crystal drive circuit into serial data and sends it to the remote meter reading receiving board via the remote meter reading transmission line, and the remote meter reading receiving board also has an impeller. A fluid flow meter characterized by being equipped with a pilot display mechanism that flashes in synchronization with rotation.