JPH0222669Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a water level difference measuring device in an automatic cylinder pressure measuring device.

High-pressure cylinders such as LP gas cylinders and oxygen cylinders are required to undergo pressure resistance measurements at the time of manufacture and re-inspection, and it is stipulated that there is no leakage or abnormal expansion, and that the permanent increase rate is below a certain value.

The conventional measuring device used in the water tank type test method was to visually read and measure the level of the liquid in the burette tube.

Although capacitive water level detectors have been developed to overcome the inaccuracies caused by visual measurements, they have the following drawbacks.

Due to dirt in the water, the capacitance of the water changes,
Measurement errors are likely to occur.

Due to dirt on the filter, water droplets may adhere to the inner wall and the surface tension of the water may change, making it difficult to accurately detect the water level.

The above maintenance and inspection requires time and effort.

The present invention aims to solve the above-mentioned problems and provide a useful device with high detection accuracy.The present invention aims to solve the above-mentioned problems and provide a useful device with high detection accuracy. A pulse oscillator that is in communication with a calculator that converts the amount of liquid and oscillates a number of pulses in proportion to the rotation speed of the drive shaft, a fixed electrode that is lowered into the burette from its upper opening, and a water pipe at the bottom of the burette. connected to the conductor provided between and the fixed electrode,
It has a detection circuit with a low frequency oscillator, and when the water surface inside the burette comes into contact with the fixed electrode as the burette moves up and down by the drive shaft, the detection circuit converts the potential difference that occurs across the resistor into an output signal, and outputs the output signal. The present invention is characterized in that it includes a water level detection element that emits as an activation signal to the pulse oscillator.

An example of implementing the present invention will be described below. 1
is a biuret, and this biuret 1 is integrally equipped with an actuating body 3 that is screwed onto a screw-like drive shaft 2, and the drive shaft 2 rotates in forward and reverse directions under the driving force of a motor 4. The drive shaft 2 is connected to a pulse oscillator 6 which is connected to a calculator 5.

The brewet 1 is a tubular body made of an insulating and non-magnetic material, and a fixed electrode 7 in the form of a stainless steel rod is inserted from the top opening into the liquid chamber 1a, preferably at the center of the tube.
is lowered halfway, and the burette tube 1 is movable up and down relative to the fixed electrode 7. A conductor 8 is attached to the lower end of this filter 1,
A water pipe 11 communicates with the water tank 12 via a communication pipe 9 and a solenoid valve 10 that can be expanded and contracted up and down.
A water supply pipe 15 extending from the supply tank 13 and having a solenoid valve 14 and a water flow pipe 18 having a solenoid valve 16 and connecting to an overflow tank 17 are connected in the middle of the water pipe 11. The overflow tank 17 is arranged so that its overflow port is located at a higher level than the lower tip of the fixed electrode 7.

Detection circuit 1 connected to fixed electrode 7 and conductor 8
9 is a low frequency oscillator 20, a resistor 21, an input amplifier 22, a bandpass filter 23, a rectifier circuit 24,
Consisting of a comparator 25, when the water surface touches the fixed electrode 7, the detection circuit activates a low frequency oscillator - resistor -
A closed circuit is formed between the fixed electrode, water, conductor, and low frequency oscillator, and current flows. This current is output by a low frequency oscillator 20. This current generates a potential difference in the resistor 21, which is input to the input amplifier 22. For the output of the input amplifier 22, only the frequency component signal output from the low frequency oscillator 20 is selected by the band pass filter 23. Furthermore, since the output of the band pass filter 23 is an AC component, it is converted to a DC component through a rectifier circuit 24 and then sent to the comparator. input to the controller 25. The comparator 25 generates an output signal when the DC component reaches a certain level,
The pulse oscillator 6 is configured to generate the signal as an activation signal.

The pulse oscillator 6 uses the output signal from the detection circuit 19 to determine the rotational speed of the drive shaft 2 during the raising of the burette 1 from the time of zero point setting to the time of secondary pressurization and from the time of secondary pressurization to the time of depressurization. The calculator 5 oscillates a number of pulses proportional to .

Calculator 5 converts the number of pulses into liquid volume and calculates the amount of increase in liquid from the time of zero point setting to the time of secondary pressurization, that is, the total increase, and the amount of liquid increase from the time of secondary pressurization to the time of depressurization. Calculate and display the permanent increase amount minus the decrease amount.

The pressurizing mechanism system of cylinder B includes a pressurizer 26, a water pipe 28 leading to a hanging pipe 27 of cylinder B, a pressurizing solenoid valve 29 on the way of this water pipe 28, and a drain provided branching off from the pipe 28. The pressure solenoid valve 30 is equipped with a pressure solenoid valve 30, and the above-mentioned operations and controls including this pressurizing mechanism system are controlled to operate in a timely manner, and can be operated automatically or manually as desired.

Next, to explain the pressure resistance measurement state of cylinder B in the case of automatic measurement, cylinder B is suspended in water tank 12, sealed with lid 31, and air is vented through valve 32.

At this time, the solenoid valve 30 is open, but the other solenoid valves 10, 14, 29, and 16 are closed. After sealing and air venting are completed, the valves 32, 32 are closed, and then the solenoid valve 10 is opened to complete the setting.

After that, the zero point adjustment is started, the solenoid valves 14 and 16 are opened, and water from the make-up water tank 13 passes through the water supply pipe 15 and fills the water tank 12, and at the same time flows into the burette 1, which can be raised and lowered by the drive of the motor 4. , and flows into the overflow tank 17 from the water pipe 18. When the tank 17 is replenished until it overflows from its overflow port, the fixed electrode 7 detects this and closes the solenoid valve 14. At this point, the water level of the liquid in the brewet 1 is higher than the lower end of the fixed electrode 7, and the level of the liquid in the overflow tank 1 is higher than the lower end of the fixed electrode 7.
It is on the horizon with the overflow mouth of No. 7.

After the electromagnetic valves 14 and 16 are closed, the brewet 1 is lowered by the drive shaft 2 which can rotate forward, and at the moment the water level of the liquid in the brewet 1 separates from the lower end of the fixed electrode 7, the water level detection element A is detected. The water level is detected and the output signal is transmitted to the pulse oscillator 6 to set the zero point level. The brewet 1 then lowers and stops.

After the zero point setting is completed in this way, the first pressurization starts, and the solenoid valve 29 opens. Water is pressurized into the cylinder B from the pressurizer 26, and when the water is pressurized to 25 kg/cm ² , the solenoid valve 29 is opened. 29 is closed for a certain period of time, and after checking for pressure leaks, the solenoid valve 29 is opened again to proceed to the second pressurization, and pressurizes to 31 kg/cm ² . At this time, the water level in the barrel 1 is rising in proportion to the degree of expansion of the cylinder B. When the same pressure is reached, the solenoid valve 29
It closed for 30 seconds, and at the same time, the brewet 1 began to descend, and the moment the water surface separated from the fixed electrode 7 again,
A signal from the water level detecting element A that detects this is sent to the pulse oscillator 6, which causes the brewet 1 to stop descending (3) and the number of pulses from the zero point setting of this brewet to the time it stops descending, that is, from the time of the above zero point setting. The amount of increase in the liquid up to the second pressurization, that is, the total amount of increase in the cylinder B is calculated by the calculator 5 and displayed.

After measuring the total amount of increase, the process immediately proceeds to measurement of the amount of permanent increase, and at the same time as the 30 second timer expires, the depressurization solenoid valve 30 opens and the pressure in the cylinder B is depressurized. Accordingly, the water level in the barrel 1 falls in proportion to the degree of shrinkage of the cylinder. At the same time as the pressure is removed, the brewet 1 moves up, and at the moment the water surface contacts the fixed electrode 7, the water level detection element A sends a signal to the pulse oscillator 6, and while the brewet 1 stops moving up, the pulse oscillator 6 The number of pulses corresponding to the difference in liquid level from the time of measuring the total increase in volume until after the pressure is removed is sent to the calculator 5, and the calculator 5 converts the number of pulses sent to calculate the permanent increase in cylinder B. and display.

After the total increase and permanent increase in cylinder B are automatically measured and recorded in this manner, each mechanical system returns to its initial state and moves on to measuring the withstand pressure of the next cylinder B again.

The present invention has the following embodiment effects.

In this water level difference measuring device, the differential amplifier works by removing noise such as power frequency components induced in the connection line between the sensing end and the circuit, so the influence of this noise can be eliminated. Then, the bandpass filter cuts out the noise component (power frequency component) of the signal from the detection end, and removes the power frequency (50Hz, 60Hz) used in the device, which is generated by the low frequency oscillator.
It works by energizing specific frequency components different from those in

(Effect of idea) Therefore, the present invention has the following advantages.

It is accurate because it directly detects the water surface.

Since a low frequency oscillator is used, there is less dirt on the contact surface. Further, there is little variation in the contact pressure for energizing.

Errors caused by the commercial power supply used in the equipment can be ignored.

As the water gets dirty, the resistance of the water decreases, allowing for more accurate measurements.

Since a low-frequency oscillator is used, chemical changes in the electrodes that occur when direct current is used in the detection circuit are eliminated, allowing stable and accurate water surface detection for long periods of time, and water resistance is large when high-frequency current is used. Therefore, there is no problem that the detection sensitivity decreases.

Can accurately measure cylinder pressure resistance.

[Brief explanation of the drawing]

FIG. 1 is a system diagram showing an embodiment of the present invention.
FIG. 2 is a circuit diagram of the detection circuit. In the figure, A is a water level detection element, B is a cylinder, 1 is a barrel, 2 is a drive shaft, 5 is a calculator, 6 is a pulse oscillator, 7 is a fixed electrode, 8 is a conductor, 11 is a water pipe, and 19 is a detection circuit , 20 is a low frequency oscillator, 21
is a resistor.

Claims (1)

[Scope of utility model registration request] Biuretsu, which is connected to the inside of the aquarium by a water pipe,
A drive shaft that drives the brewet up and down, a pulse oscillator that communicates with a calculator that converts the number of pulses into liquid volume, and oscillates a number of pulses in proportion to the number of rotations of the drive shaft, and is lowered into the brewet from its upper opening. a detection circuit connected to the fixed electrode and a conductor provided between the fixed electrode and the water pipe at the lower end of the filter, and having a low frequency oscillator;
As the burette moves up and down with the drive shaft, the water surface inside the burette comes into contact with the fixed electrode, and a detection circuit converts the potential difference that occurs across the resistor into an output signal, and the output signal is sent to the pulse oscillator as an operating signal.Water level detection Water level difference measuring device in automatic cylinder pressure measuring device equipped with elements.