JPH09195973A - Automatic operative device for electric pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify a structure of an electrode-type liquid level detecting part and also to improve the detecting sensitivity, so as to provide an automatic driving device in which electrolytic corrosion is not easily generated on the electrode and on the periphery of it, in an electric pump taking conductive liquid or solid-liquid mixture as an transferring object and to be used in the transferring object. SOLUTION: An electrode 4 electrically insulated and guided out from a conducive outer casing 3 of an electric pump 2 is taken as a first electrode, the outer casing 3 is taken as a second electrode, the liquid level is detected by the electrification of the first electrode 4 and the second electrode 3 through conductive liquid subjected to transference or solid-liquid mixture, the electric pump 2 is operated on the basis of the detected signal, and transmission of the signal is stopped.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an automatic operating apparatus for an electric pump.

[0002]

2. Description of the Related Art Conventionally, in an electric pump provided with an electrode type liquid level detecting device, a direct current is applied between two electrodes 4A and 4B electrically insulated from the pump body as shown in FIGS. A voltage was applied and the pump was operated by detecting the liquid level depending on the presence or absence of conduction. And both electrodes 1A, 1B
The application of the above DC voltage to is constantly performed even during pump operation.

As described above, in the conventional liquid level detecting device configured to detect the conduction by the DC voltage between the two electrodes 4A and 4B to stop the operation of the pump, the current path distribution is as shown in FIG. Since the conductive detection area of the transferred liquid is only between the two electrodes 4A and 4B having a small surface area, the detection function does not work when a liquid having a large DC resistance value is to be transferred, and therefore the automatic pump operation is not possible. I can't let it happen. The detection function works only when the liquid to be transferred has extremely good conductivity.

Further, in the conventional liquid level detecting device, as shown in the timing chart of FIG. 8, the DC voltage is constantly applied during the time K during which the transfer liquid is interposed between the two electrodes 4A and 4B, so that the voltage is constantly applied. The electrodes are easily damaged by corrosion,
It will lead to driving disability. Furthermore, since at least two electrodes that are separately insulated from the pump main body are required, the structure becomes complicated and this is a factor of increasing the manufacturing cost.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to simplify the structure of an electrode type liquid level detection unit in an electric pump which is used in a conductive liquid or solid-liquid mixture as a transfer target and is used in the liquid or solid-liquid mixture. In addition, the detection sensitivity is improved, and an automatic operation device in which electric corrosion does not easily occur on the electrode and its peripheral portion is provided.

[0006]

According to the present invention, in an automatic operating apparatus for an electric pump, which uses a conductive liquid or solid-liquid mixture as a transfer target and is used in the liquid or solid-liquid mixture, an electrically conductive outer casing of the pump and an electric The electrode that is insulated and led out is the first electrode, the conductive outer casing is the second electrode, and the first electrode and the second electrode are through the conductive liquid or solid-liquid mixture to be transferred. Is electrically connected to detect the liquid level, and the pump is operated based on the detection signal. If necessary, the liquid level is detected by applying an AC voltage. Then, the AC voltage is configured so that power supply is stopped during pump operation.

[0007]

Embodiments will be described below with reference to the drawings of the embodiments.

1 is a conductive liquid or solid-liquid mixture to be transferred, 2 is an electric pump used in the conductive liquid or solid-liquid mixture, 3 is an outer casing of the pump 2, Made of conductive material such as metal. Reference numeral 4 denotes an electrode which is electrically insulated from the outer casing 3 and is led out. The electrode may be fixedly planted with its tip facing outward, or may be installed by being extended to a position away from the electric pump 2. Good.
The electrode 4 is used as a first electrode, and the outer casing 3
Is the second electrode.

If electrical conduction occurs between the first electrode 4 and the second electrode 3, it means that the conductive liquid or the solid-liquid mixture to be transferred was present, and therefore the liquid level is caused by the electrical conduction. Can be detected and the electric pump 2 can be operated based on the detection signal. When the electric conductivity of the liquid or the solid-liquid mixture to be transferred is utilized and the electric pump 2 is automatically operated according to the conductive state in this way, the electric conductivity is detected by applying an AC voltage. Generally, the electric resistance of an object is classified into a DC resistance and a capacitive AC resistance. However, when an AC voltage is applied, for example, an object with a very large DC resistance and almost no current flows has a small capacitive AC resistance If an object, that is, an object having a large capacitance, it can be detected that these objects are present between the electrodes.
That is, the applied effective voltage required to obtain a detection signal equivalent to the DC detection signal obtained by applying the conventional DC voltage can be low. Then, in order to further reduce the AC resistance value and increase the detection accuracy, the capacitance may be increased or the frequency may be increased. It is electrically easy to increase the frequency. In order to increase the electrostatic capacity, it suffices if the object to be transferred itself has a large dielectric constant, but if the object to be transferred is the same, the distance between the electrodes should be reduced and the surface area of the electrodes should be increased to increase the electrostatic capacity. You can increase it. If the outer casing 3 of the pump is the second electrode, as in the device of the present invention, the surface area is extremely large, so that the capacitance can be increased.

In the device of the present invention, since the second electrode serves as the outer casing 3 of the pump, the current path distribution from the first electrode 4 through the transfer object is as shown in FIG. Since it flows toward, the impedance between the electrodes 4 and 3 as a whole is lowered, the detection signal becomes large, and the liquid level detection becomes easy and reliable. In addition, the fact that the surface area of the second electrode 3 is large also means that the current density flowing through the second electrode 3 is relatively reduced at the same applied voltage, and electrolytic corrosion is reduced.

When the electric pump 2 starts operating in response to the detection signal a, the operation processing unit 13
A transmission operation signal d is sent to stop the operation of the transmission unit 11, and the application of the AC voltage from the transmission unit 11 to the first electrode 4 is stopped. For example, the driving processing unit 13 sends the driving signal c by a timer or the like for a certain period of time, and the transmitting unit 1 immediately before the time is up.
When 1 is operated again and an AC voltage is applied to the first electrode 4 to obtain the detection signal a, the timer of the operation signal c is set again and the operation of the electric pump 2 is continued. If the detection signal a is not obtained, the operation of the electric pump 2 is stopped after the operation time c is delivered. Even if the conductive liquid or the solid-liquid mixture 1 is interposed between the electrodes 3 and 4, the start-up k section and the operation signal until the detection signal a is detected and the transmission unit 11 stops transmission as shown in FIG. Immediately before the time for sending c is reached, only the section i in which the detection signal a is detected again and the timer for sending the operation signal c is set again is the section in which current flows through the electrodes, and the voltage applied to the first electrode 4 Will be stopped for most of the time during pump operation,
The passing current between electrodes that should be the detection signal a is extremely short even in total time, and the possibility of occurrence of electrolytic corrosion is drastically reduced. The voltage is continuously applied to the first electrode 4 because both electrodes 3, 4
When the conductive liquid or the solid-liquid mixture 1 is not interposed between them, almost no current flows between the electrodes 3 and 4 during this time, so there is no possibility of occurrence of electrolytic corrosion.

[0012]

The effects of the present invention are as follows.

First, since the outer casing of the pump is used as one of the electrodes, only one electrode rod needs to be installed in the conventional pump, and an insulating structure attached to this electrode rod is also provided in one place. The structure is simple and the manufacturing cost can be reduced.

Secondly, since one of the electrodes is the outer casing, the resistance value between electrodes of the conductive liquid or the solid-liquid mixture to be transferred by the pump can be reduced, the detection signal becomes large, and the detection sensitivity is improved. To do.

Thirdly, since the voltage applied to the electrodes is AC, even a transfer object having a large DC resistance can be detected if the AC impedance is low and the pump can be automatically operated and handled as a transfer object. The variety of liquids increases.

Fourth, since one of the electrodes is the outer casing of the pump, the surface area is large, and as a result, the capacitance of the object to be transferred becomes large, so that the AC resistance between the electrodes is reduced and the detection signal is increased. The detection sensitivity is improved.

Fifthly, the application of AC voltage to the electrodes is stopped for a certain period of time at the same time as the pump operation, and when an object to be transferred is present between the electrodes, it is energized only for the re-detection time, so almost no electrolytic corrosion occurs Will not occur.

Sixth, since one of the electrodes is the outer casing of the pump, the surface area of the electrode is large, the current density flowing through the electrode is low, and the possibility of electric contact is reduced.

[Brief description of the drawings]

FIG. 1 is a vertical cross-sectional side view showing a usage state of an electric pump provided with a device of the present invention.

FIG. 2 is a vertical side view showing a usage state of an electric pump provided with a conventional electrode type liquid level detection device.

FIG. 3 is a block diagram of an electric circuit in the device of the present invention.

FIG. 4 is a block diagram of an electric circuit in a conventional electrode type liquid level detection device.

FIG. 5 is a current path distribution diagram between the first electrode and the second electrode in the device of the present invention.

FIG. 6 is a current path distribution diagram between a first electrode and a second electrode in a conventional electrode type liquid level detection device.

FIG. 7 is a timing chart when the device of the present invention is implemented.

FIG. 8 is a timing chart when a conventional electrode type liquid level detection device is implemented.

[Explanation of symbols]

 1 conductive liquid or solid-liquid mixture (transfer target) 2 electric pump 3 external casing (second electrode) 4 electrode (first electrode)

Claims (3)

[Claims] 1. An automatic operating device for an electric pump, which is used in a liquid or solid-liquid mixture, wherein a conductive liquid or solid-liquid mixture is to be transferred, and is electrically insulated from a conductive outer casing of the pump. The derived electrode is the first electrode,
The conductive outer casing is used as a second electrode, and the liquid level is detected by electrically connecting the first electrode and the second electrode through a conductive liquid or a solid-liquid mixture to be transferred, An automatic operation device for an electric pump, characterized in that the pump is operated based on the detection signal. 2. The automatic operating apparatus for an electric pump according to claim 1, wherein the liquid level is detected by electrical conduction between the first electrode and the second electrode by applying an AC voltage. . 3. An AC voltage applied to detect a liquid level due to electrical conduction between the first electrode and the second electrode is configured so that power supply is stopped during pump operation. An automatic operation device for an electric pump according to claim 1.