JPS5940212A - Liquid level measuring device - Google Patents

Abstract

PURPOSE:To make the entire body compact, by providing an annular magnet in the inside of a ring shaped float, which is floated on the liquid surface, and inserting a belt shaped substrate in a pipe with a bottom, which is inserted in the ring shaped float. CONSTITUTION:A ring shaped float 2 is formed by a corrosion resisting material such as stainless steel and synthetic resin, and floated on the surface of a liquid in a tank 1. An annular permanent magnet 4 is provided in the inside of the ring shaped float 2. A long, belt shaped, flexible substrate 5 is inserted in a pipe 3 with a bottom. An electric circuit is constituted on the substrate 5. Said electric circuit is provided with a group of magnetoresistance elements 6, 6a, 6b, 6c..., which are arranged at a constant interval. In this constitution, the entire body can be made compact.

Description

[Detailed Description of the Invention] Generally, a liquid level measuring device detects the position of a float on the liquid surface. In addition to being readable by a liquid level needle installed on-site, the rotation angle of the output shaft of the liquid level needle can also be converted into a code signal and sent to the receiving side.

However, in this general liquid level measuring device,
This method lacks reliability due to distortions that occur before it is encoded, and the equipment is also complicated, making it more likely that failures will occur.

Therefore, the present invention provides a liquid level measuring device in which a measurement detection rock structure is provided directly inside the tank, the whole is made compact, distortion is eliminated during detection, and highly reliable measurement can be performed. The idea is that a ring-shaped float that floats on the liquid surface is equipped with an annular magnet on the inner surface, and a strip-shaped substrate is inserted into a bottomed pipe that is inserted through the ring-shaped float. An electric circuit is constructed of a group of magnetoresistive elements arranged at regular intervals and a group of D-type flip-flops connected in series, and the liquid level can be adjusted by sequentially scanning the magnetoresistive element groups. It resides in the liquid level measuring device that detects it.

Next, an example of implementation of the present invention will be described with reference to the drawings.

In the figure, 1 is a tank, 2 is a ring-shaped float made of a corrosion-resistant material such as stainless steel or synthetic resin, and 3 is a bottomed pipe that also serves as a guide and made of a corrosion-resistant material such as stainless steel or synthetic resin. It is installed vertically inside the tank.

The ring-shaped float 2 is equipped with an annular (including intermittent annular) permanent magnet 4 on its inner surface, and a flexible substrate 5 in the shape of a long silk band is inserted into the bottomed pipe 3. This board 5 is configured with an electric circuit, and this electric circuit includes a group of magnetoresistive elements 6, 6a, 6b, 6c, . . . arranged at regular intervals.
The arrangement is according to the smallest unit of the liquid level to be measured, for example I
They are arranged accurately at ITIr11 intervals, lQrrm intervals, etc.

Furthermore, this electrical circuit has a D-type flip-flop tab 7.7.
a , 7b , 7c , 7d , , , , are iM,
A column K-connection M-sash circuit is provided.

To start the measurement, a set signal is applied from the initial set signal terminal 8 to set the flip-flop 7 to have a Q output and the flip-flops 7a to 7d to have a Q output. Here, Q output is If Q If →II Q I
f, II I If + II I It with te, Q
The output is If □ tI → II I It, II I I
I + n Q If. Then clock input terminal 9
When clock inputs are sequentially applied from , the Q side output state advances one by one seven lip-flops per clock pulse.

Assuming that 6C of the magnetoresistive elements 6 to 6C connected to the clock inputs of flip-flops 73 to 7d is sensing the magnetic force, the 7th flip-flop 7C enters the Q output state at the third pulse of the clock. , this state is supposed to advance to the flip-flop 7d with the next fourth pulse, but the magnetoresistive element 6C senses the magnetic force and is in a non-conducting state, so the Q output state does not advance to the flip-flop 7d. In addition, the Q output of the previous flip-flop 7N) is shifted to the flip-flop 7C, and since the Q output of the initial state from the flip-flop 7d onward is shifted every clock, all of them are in the Q output state, and as a result, The Q output state disappears from the flip-flop group at the fourth clock pulse.

On the other hand, each 7 flip-flop 7, 'IEk, 7b,...
The Q side outputs of buffers 10, 10a, 10b6 . ,,,
It is wired OR connected to the sense line of the end output terminal 11 via the terminal 11, and the disappearance of the Q output state from the flip-flop group is sensed by the output of the sense line.

In this way, the value of the liquid level from the reference point can be determined by the pulse of the clock at which the sense line output is obtained. For example, in the case of the above example, if the magnetoresistive element 6 is set to the reference liquid level, the Q output disappears at the fourth pulse, so
The measurement value is 3 nodules, and if the interval between the magnetoresistive elements is 1 cm, the liquid level from the reference point will be measured as 1 cm/1 pulse x 3 pulses = 3 cm.

The reason why the magnetoresistive element is not connected to the clock input of the flip-flop 7 is that when this element is sensing magnetic force, no clock is input to the flip-flop 7, and therefore the initial set Q output state of the flip-flop 7 is This is to prevent it from remaining forever unrelated to the clock.

Figure 3 shows the control circuit of this measuring device, and 12 indicates a clock pulse generation circuit.The clock pulses generated here are appropriately frequency-divided by the next-stage program counter, outputting the initial set signal, and generating the head mark. output,
Performs the operation of setting the measurement time period. When the initial set signal is output from the oscillator 13, the flip-flop group is set as described above, and at the same time, the seven flip-flops 14 are set to prepare for measurement.

Next, output the head mark, and this output is OR gate 1
5 to the receiving needle to notify the start of measurement value transmission. Subsequently, when the measurement time period arrives, the AND gate 16 is opened and the terminal 17 passes the clock, and this clock is sequentially applied to the flip-flop group from the clock terminal 9.
While the Q output state is shifted one pulse at a time, the output of the flip-flop 14 set in the initial state passes through the open AND gate 18, and then the program counter returns to the initial set state when the measurement time period ends. Go back and repeat the above-described transmission operation periodically.

Note that the terminal 19 in the figure is connected to the terminal 8, and the terminal 20 is connected to the terminal 11.
connected to.

In addition, in the receiver (not shown), an integrating circuit or the like detects a long head mark, counts the number of pulses after the mark with a counter, and repeats the operation of shifting this to the latch circuit for the next mark. Further, a receiving operation is performed in which the contents of the latch are converted into codes and displayed.

Furthermore, in order to transmit the output by the number of pulses, for example, 30.
To transmit data of 000 rrm (30m) (
), 000 pulses of data are required, resulting in a lot of wasted time. In such a case, by operating the transmitter at high speed, counting once with a counter, and transmitting this content as a serial code, it is possible to shorten the word length of the entire transmitted data and shorten the time required for transmission. ,
In this case, it is also possible to change the head mark, which is a wide pulse, to a head code having a special code.

The liquid level measuring device according to the present invention has the above-mentioned configuration,
There is no loss until the detected value is encoded, and the entire system can be made more compact. Additionally, since the electrical circuit can be installed in the pipe inside the tank, the measured values are more accurate and the failure rate can be reduced.

[Brief explanation of drawings]

FIG. 1 is a schematic front view showing the implementation state of the device of the present invention, and FIG.
The figure is a schematic sectional view showing the main parts, and FIG. 3 is a control circuit diagram. 2 in the figure Flute 3 Bottomed pipe 4 Permanent magnet 5 Substrate 6.6a, 6b, 6c Magnetic resistance element 7.7a, 7b
, 7c, 7d 7lip 7E:'7" Applicant
Tokyo Keiso Co., Ltd. Agent Patent Attorney Former 1) Kiyomi

Claims (1)

[Claims] A vertical pipe is provided in the tank, a float that moves up and down along the pipe as the liquid level changes and has a magnet is provided on the liquid surface, and a vertically elongated substrate is provided in the pipe, An electric circuit is formed on this board, consisting of a group of magnetoresistive elements arranged vertically at regular intervals and a group of seven D-type lip-flops connected in series, and a float that moves up and down as the liquid level changes. A liquid level measuring device in which a group of magnetoresistive elements is sequentially scanned by the magnet.