JP2804893B2 - Water level difference measuring device in automatic pressure measuring device for cylinders - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water level difference measuring instrument in an automatic cylinder pressure measuring device.

[0002]

2. Description of the Related Art High-pressure cylinders, such as LP gas cylinders and oxygen cylinders, are required to undergo pressure measurement at the time of manufacture and re-inspection. There is no leakage or abnormal expansion, and the permanent increase rate is specified to be below a certain value. Have been.

[0003] A conventional measuring device in the water tank type test method is to read and measure the liquid level of the liquid in the burette tube by eye. In addition, although there is a capacitance type water level detector for eliminating inaccuracy by eye measurement, it has the following disadvantages. a. Due to contamination of the water, the capacitance of the water changes, and a measurement error easily occurs. b. Due to dirt on the burette, water droplets adhere to the inner wall and the surface tension of the water changes, making it difficult to accurately detect the water level. c. The above-mentioned a and b require time and labor for maintenance and inspection.

As a solution to the above-mentioned problems of the conventional water level detector, the applicant has proposed a water level difference measuring device described in Japanese Utility Model Publication No. 2-22669. This device communicates with the burette that communicates with the inside of the water tank by a water pipe, a drive shaft that drives the burette up and down, and a calculator that converts the number of pulses into a liquid volume, and is proportional to the rotation speed of the drive shaft. A pulse generator that oscillates the number of pulses, a fixed electrode lowered from the upper end opening in the burette, a conductor provided between the water pipe at the lower end of the burette and the fixed electrode, It has a detection circuit having a frequency oscillator, and converts a potential difference generated in the resistor into an output signal by the detection circuit as the water surface in the burette comes into contact with the fixed electrode as the buret moves up and down by the drive shaft, and outputs the output signal. The pulse oscillator is provided with a water level detecting element for emitting a signal to the pulse oscillator as an operation signal.

The following features are provided. . Accurate because it directly detects the water surface. . Since the low-frequency oscillator is used, there is little contamination on the contact surface. Also, there is little variation in the contact pressure to be energized. . Errors due to the commercial power used in the equipment can be ignored. . As the water becomes dirty, the resistance of the water decreases, so that more accurate measurement can be performed. . The use of a low-frequency oscillator eliminates chemical changes in the electrodes when DC current is used for the detection circuit, enables stable and accurate water level detection for a long time, and increases the water resistance when high-frequency current is used. Therefore, there is no inconvenience that the detection sensitivity is lowered. . Accurate pressure measurement of cylinders.

By the way, when the zero point is adjusted at the time of measuring the pressure resistance of the cylinder, water is supplied from a replenishing tank to a water tank, a burette, and an overflow tank. Stops the water supply from the replenishment tank, and then moves the burette down, detects the moment when the water surface in the burette leaves the fixed electrode with the water level detection element, and pulses its output signal. The zero point is transmitted to the oscillator.

[0007] Therefore, there is a problem of economy due to an increase in equipment of the overflow tank, a problem of work time and work efficiency by supplying water from the replenishment tank until it overflows from the overflow port of the overflow tank, an overflow tank of the overflow tank and a fixed electrode. There are inconveniences such as a problem of poor zero point setting when the vertical positional relationship with the lower end is incorrect.

[0008]

The problem to be solved is to improve the structure in which the zero point adjustment is performed using an overflow tank, and to provide the overflow tank capability in the burette, thereby achieving the above-described economical efficiency and workability. , So that various problems of the zero point setting failure can be solved.

[0009]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the present invention provides a burette communicating with the inside of a water tank by a water pipe, a drain pipe connected to the water pipe and having a valve, and a burette that moves up and down. The drive shaft to be driven, a pulse oscillating element that communicates with the calculator that converts the number of pulses into a liquid volume, and that oscillates the number of pulses in proportion to the rotation speed of the drive shaft, is installed in the burette from its upper end opening. A fixed electrode, a detection circuit having a low-frequency oscillator connected to a conductor provided between the water pipe at the lower end of the burette and the fixed electrode, wherein the valve of the drain pipe opens and closes. As the water level in the buret rises and touches the fixed electrode as the replenishment of the water tank and the buret via the valve from the water supply pipe communicating with the water pipe after the inside of the burette is drained, the output signal is output. Valve closed It is emitted as an actuation signal, and as the burette is raised and lowered by the drive shaft, a potential difference generated in the resistor is converted into an output signal by a detection circuit as the water surface in the burette comes into contact with the fixed electrode, and the output signal is converted to the output signal. The pulse oscillation element includes a water level detection element that emits an operation signal.

According to the present invention, the fixed electrode has an acute-angled tip.

[0011]

[Function] A burette communicating with the inside of the water tank by a water pipe,
A drain pipe connected to the water pipe and having a valve, a drive shaft for driving the burette up and down, and a calculator for converting the number of pulses into a liquid amount are communicated, and the number of pulses is proportional to the number of rotations of the drive shaft. A pulse oscillation element that oscillates, a fixed electrode that is lowered from the upper end opening in the buret, a conductor provided between the water pipe at the lower end of the burette, and the fixed electrode are connected to the low frequency oscillator. After the valve of the drainage pipe is opened and closed and the inside of the burette is drained, the detection circuit has a water supply pipe communicating with the water pipe after the valve is supplied to the water tank and the burette via the valve. As the water surface rises and touches the fixed electrode, an output signal is issued to the valve as an actuation signal for closing the valve, and as the burette moves up and down by the drive shaft, the water surface in the burette contacts the fixed electrode. The detection circuit converts the potential difference generated in the resistor into an output signal, and the pulse oscillation element has a water level detection element that emits the output signal as an operation signal. When the water level in the burette rises and touches the fixed electrode, the valve of the water supply pipe can be closed to stop the water supply, and the water supply can be stopped. You can get ready.

[0012] Apart from replenishing the water tank, the adjustment preparation for setting the zero point can be prepared only by replenishing the inside of the burette, so that the overflow tank can be made unnecessary and the equipment of the tank is increased. Economic issues,
Problems in work time and work efficiency due to water supply from the replenishment tank until it overflows from the overflow tank overflow, and poor zero setting when the vertical position relationship between the overflow tank overflow and the fixed electrode bottom is inaccurate. Can be solved at once.

Further, since a drain pipe having a valve is connected to the water pipe, the inside of the burette is drained before the start of water supply prior to the measurement, and in preparation for adjustment for setting the zero point,
Preparations can be made in advance.

Further, since the fixed electrode has an acute-angled tip, the accuracy of detecting the water level is improved.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below.
Reference numeral 1 denotes a burette. The burette 1 is integrally provided with an operating body 3 screwed to a screw-shaped drive shaft 2. The driving shaft 2 is connected to a pulse generator 6 which is connected to a calculator 5.

The burette 1 is a tubular member made of an insulating and non-magnetic member, and a stainless steel rod-shaped fixed electrode 7 is set down from the upper end opening to a desired position in the liquid chamber 1a. The burette tube 1 can freely move up and down with respect to the fixed electrode 7. A conductor 8 is attached to the lower end of the burette 1, and a communication pipe 9, which is vertically expandable and contractible, and a water pipe 11 communicating with a water tank 12 via a solenoid valve 10 are connected. A supply tank on the way
A water supply pipe 15 extending from 13 and having a solenoid valve 14 is connected. A drain pipe 17 having an electromagnetic valve 16 is connected between the communication pipe 9 and the electromagnetic valve 10 in the water pipe 11.

A detecting circuit 18 having a lower end connected to the fixed electrode 7 and the conductor 8 having an acute angle has a low frequency oscillator 19, a resistor 20,
It comprises an input amplifier 21, a band-pass filter 22, a rectifier circuit 23, and a comparator 24. When the water surface touches the fixed electrode 7, the detection circuit becomes a low-frequency oscillator-resistor-fixed electrode-water-
A closed circuit is formed between the conductor and the low-frequency oscillator, and the current I flows. This current is output by the low frequency oscillator 19. Due to this current I, a potential difference occurs in the resistor 20 and the input amplifier 21
Is input to As the output of the input amplifier 21, only the signal of the frequency component output from the low-frequency oscillator 19 is selected by the band-pass filter 22, and the output of the band-pass filter 22 is an AC component. Input to the radiator 24. Comparator 24
Generates an output signal when the DC component reaches a certain level, and outputs it to the pulse oscillator 6 as an operation signal.

The pulse oscillator 6 operates from the time of setting the zero point to the time of the second pressurization and the second
Calculator 5 calculates the number of pulses in proportion to the number of rotations of drive shaft 2 during the movement of burette 1 from the next pressurization to the depressurization.
Oscillation. The calculator 5 converts the number of pulses into a liquid amount, and calculates the amount of increase of the liquid from the time of setting the zero point to the time of the second pressurization, that is, the total increase amount, and the amount of liquid from the time of the second pressurization to the time of the depressurization. And the permanent increase obtained by subtracting the decrease amount of is calculated and displayed.

The pressurizing mechanism of the cylinder B is provided by a pressurizer 25, a water pipe 27 leading to a suspension pipe 26 of the cylinder B, a solenoid valve 28 for pressurizing the water pipe 27, and a branch from the pipe 27. The pressure-reducing solenoid valve 29 is provided, and the above-described operation and control including the pressurizing mechanism system are controlled to operate at appropriate times, and can be automatically or optionally manually operated.

Next, the pressure measurement state of the cylinder B will be described in the case of automatic measurement.
Seal at 30 and bleed air from valve 31. At this time, the solenoid valve 29 is open, but the other solenoid valves 10, 14, 28, and 16 are closed. After sealing and bleeding are completed, valves 31, 31
Is closed, and then the solenoid valve 10 is opened to complete the setting.

After that, the operation shifts to the zero point adjustment, the solenoid valve 14 is opened, and the water from the makeup water tank 13 passes through the water supply pipe 15 to fill the water tank 12 and at the same time is moved into the burette 1 which can be moved up and down by the drive of the motor 4. When water is supplied and replenished until the water surface rises and touches the lower end of the fixed electrode 7, the fixed electrode 7 detects this and closes the solenoid valve 14. At this point, the liquid level of the liquid in the burette 1 is higher than the lower end of the fixed electrode 7.

After the solenoid valve 14 is closed, the burette 1 is lowered by the drive shaft 2 which can rotate forward, and the burette 1
At the moment when the water level of the liquid in the inside is separated from the lower end of the fixed electrode 7, the water level detection element A detects the water level and transmits an output signal to the pulse generator 6 to set it as a zero level. Next, the burette 1 moves down and stops.

[0023] Thus after the zero setting has been completed, the process proceeds to the primary pressure, opens the solenoid valve 28, divider in the cylinder B pressurized 25
When water from the water is injected and pressurized to 25 kg / cm ² , the solenoid valve 28 is closed for a certain period of time, and after examining pressure leakage, the solenoid valve 28 is opened again to shift to the second pressurization to 31 kg / cm ^2. Press to cm ² . At this time, the water level in the burette 1 rises in proportion to the degree of expansion of the cylinder B. When the pressure is reached, the solenoid valve 28 closes for 30 seconds, and at the same time
Begins to descend, the moment the water surface separates from the fixed electrode 7 again,
This signal from the water level detection element A which has detected is sent to the pulse generator 6, the pulse from the time zero point setting of the biuret biuret 1 descends to the stop co <br/> until Fudo stop The number, that is, the amount of increase of the liquid from the time of setting the zero point to the time of the second pressurization, that is, the total increase of the cylinder B is calculated and displayed by the calculator 5.

After measuring the total increase, the process immediately proceeds to the measurement of the permanent increase. At the same time, the 30-second timer expires, and at the same time, the pressure relief solenoid valve 29 is opened, and the cylinder B is depressurized. Accordingly, the water level in the burette 1 falls according to the degree of reduction of the cylinder. Simultaneously with the pressure removal, the burette 1 moves up, and at the moment when the water surface comes into contact with the fixed electrode 7, the water level detecting element A issues a signal to the pulse oscillator 6, and the burette 1 stops moving up while the pulse oscillator 6 Is the number of pulses corresponding to the liquid level difference from the time of the previous total increase measurement to after the depressurization is sent to the calculator 5, and the calculator 5 converts the number of transmitted pulses to calculate the permanent increase of the cylinder B. Is calculated and displayed.

After the total increase and the permanent increase of the cylinder B are automatically measured and recorded in this manner, the respective mechanical systems return to the initial state, and the solenoid valve 16 is opened to drain the burette 1. Then, the process shifts to the measurement of the pressure resistance of the next cylinder B again.

Thus, the differential amplifier works by removing noise such as a power supply frequency component induced in the connection line between the detection terminal and the circuit, so that the influence of the noise can be eliminated. Then, a band-pass filter cuts a noise component (power supply frequency component) from the signal from the detection end, and a power supply frequency (50%) used in the device generated by the low-frequency oscillator.
(Hz, 60 Hz, etc.), and operates by energizing a specific frequency component different from that of the first embodiment.

In the above embodiment, the drive shaft 2 is rotated by the motor 4, and the pulse number proportional to the rotation speed of the drive shaft 2 is oscillated from the pulse oscillator 6 to the calculator 5, but the invention is not limited to this. Instead, for example, there is also a mode in which the motor 4 is changed to a servomotor (pulse & encoder) and used instead of the pulse oscillator 6 and the calculator 5. (Not shown)

[0028]

A. Effects of the Invention According to the first aspect, when zero point adjustment is performed at the time of measuring the pressure resistance of the cylinder, the valve of the water supply pipe is closed when the water level in the burette rises and touches the fixed electrode when the zero point adjustment is performed. Water supply can be stopped to prepare for zero point setting.

B. According to the same paragraph, apart from replenishing the water tank,
Only by replenishing the burette, the adjustment preparation for setting the zero point can be prepared, so that the overflow tank can be dispensed with. Various problems such as problems of work time and work efficiency due to performing until the water overflows from the overflow port of the overflow tank, and a problem of improper zero point setting when the vertical positional relationship between the overflow port of the overflow tank and the lower end of the fixed electrode is incorrect. Can be solved at once.

C. According to the above paragraph, the water surface is directly detected, so that it is accurate. Since the low-frequency oscillator is used, there is little contamination on the contact surface. Also, there is little variation in the contact pressure to be energized. Errors due to the commercial power used in the equipment can be ignored. As the water becomes dirty, the resistance of the water decreases, so that more accurate measurement can be performed. The use of a low-frequency oscillator eliminates chemical changes in the electrodes when DC current is used for the detection circuit, enables stable and accurate water level detection for a long time, and increases the water resistance when high-frequency current is used. Therefore, there is no inconvenience that the detection sensitivity is lowered. Accurate pressure measurement of cylinders.

D. The same paragraph, since the water pipe is connected to drain pipe having a valve, and drain the water supply start view the cmdlet before prior to the measurement, when adjustment preparation for zero setting, the readiness advance Can be trimmed.

E. According to the second aspect, since the fixed electrode has an acute-angled tip, the detection accuracy of the water level is improved.

[Brief description of the drawings]

FIG. 1 is a system diagram showing an embodiment of the present invention.

FIG. 2 is a circuit diagram of a detection circuit.

[Explanation of symbols]

A water level detection element B cylinder 1 burette 2 drive shaft 5 calculator 6 pulse oscillator (pulse oscillation element) 7 fixed electrode 8 conductor 11 water pipe 12 water tank 14 solenoid valve of water pipe 15 valve water pipe 16 electromagnetic of drain pipe Valve 17 Drain pipe 18 Detection circuit 19 Low frequency oscillator 20 Resistor

Claims (2)

(57) [Claims] 1. A burette communicating with the inside of a water tank by a water pipe, a drain pipe connected to the water pipe and having a valve, a drive shaft for vertically moving the burette, and a calculator for converting the number of pulses into a liquid amount. A pulse oscillating element that oscillates the number of pulses in proportion to the rotation speed of the drive shaft, a fixed electrode that is lowered from the upper end opening in the burette, and a water supply pipe at the lower end of the burette Connected to the fixed conductor and the fixed electrode, and having a detection circuit having a low-frequency oscillator, the valve of the drain pipe is opened and closed and communicated with the water pipe after the inside of the burette is drained. As the water level in the buret rises and touches the fixed electrode as the water is supplied from the water supply pipe to the water tank and the burette via the valve, an output signal is issued to the valve as an operation signal for closing the valve and the zero point is set.
As it trimmed to adjust preparation of fit, and the lifting of biuret by the drive shaft, and converts the potential difference the resistor in the detection circuit water in biuret is neither a to contact the fixed electrode output signal, the output signal A water level difference measuring device in an automatic pressure-resistant measuring device for a cylinder, comprising a water level detecting element which emits an operation signal to the pulse oscillation element. 2. The water level difference measuring device according to claim 1, wherein the fixed electrode has an acute-angled tip.