JP4391628B2 - Automatic operation device for submersible electric pump - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an automatic operation device for a submersible electric pump using a three-phase induction motor as a prime mover.
[0002]
[Prior art and its problems]
Conventionally, this type of submersible electric pump automatic operation device has been provided with a control opening / closing mechanism for controlling automatic operation on the primary side of the motor winding, and a motor on the secondary side of the motor winding. An opening / closing mechanism dedicated to protection was attached. In such a circuit configuration, since a current equivalent to the current flowing in the main circuit of the submersible electric pump flows in the control-dedicated switching mechanism, the contact capacity of the switching mechanism cannot be reduced, and therefore the switching mechanism itself is compact. It is impossible. Further, since the two types of opening / closing mechanisms for automatic operation control and motor protection are individually laid out, a large space is required inside the motor, and the pump body becomes large.
[0003]
In addition, a float type or electrode type detector is generally used to detect the liquid level fluctuation. The float type is likely to cause an operation failure or lead wire damage to the movable part, and the electrode type is electrically conductive. The detection function is impaired in a liquid with poor properties.
[0004]
OBJECT OF THE INVENTION
An object of the present invention is to provide a submersible electric pump using a three-phase induction motor as a prime mover. In addition, the open / close mechanism incorporated in the electric circuit is made compact, and one type of open / close mechanism is used for both automatic operation control and motor protection. Therefore, the pump body can be made lighter and more compact by reducing the storage space, and the liquid level detection device movable part can be operated without any damage or lead wire damage. An object of the present invention is to provide an automatic driving device in which a position sensor functions effectively.
[0005]
[Structure of the invention]
In the submersible electric pump automatic operation device according to the present invention, a three-phase induction motor is used as a prime mover of the submersible electric pump, a temperature sensor for detecting abnormal heat generation of the motor, a liquid level sensor for detecting liquid level fluctuations, and The control device for controlling the operation of the pump based on the detection signals from these sensors and the opening / closing mechanism for connecting or disconnecting the secondary neutral point of the motor winding to or from the delta connection circuit In an automatic operation device for a submersible electric pump that is incorporated in an electric circuit and has the functions of motor protection and automatic operation control in the opening and closing mechanism, the liquid level sensor faces the light emitting element and the light receiving element to one surface of the prism. The sensor-type liquid level sensor is arranged side by side, and communicates with the opening on the wall surface of the sensor cover guided in the shape of a bottom opening along the outside of the outer cover of the submersible electric pump. Yo has a drilled water passing windows and a liquid level sensor of the photoelectric faces the water passing window is mounted from the sensor cover.
[0006]
【Example】
Hereinafter, description will be made with reference to the drawings of the embodiments.
[0007]
In FIG. 1, 1 is a three-phase AC power source, 2 is a motor winding, 3 is a temperature sensor for detecting abnormal heat generation of the motor, 4 is a photoelectric liquid level sensor for detecting fluctuations in the liquid level, 5 Is a control device for controlling the operation of the pump based on detection signals from the temperature sensor 3 and the liquid level sensor 4, and 6 is a delta connection circuit for the secondary neutral point of the motor winding in accordance with a control command from the control device 5. For example, a contactless electronic power device such as a triac is suitable, but a contacted mechanical switch may also be used.
[0008]
2 to 8, 7 is an outer cover of the submersible electric pump, 8 is a sensor cover guided in the shape of a lower surface along the outside of the outer cover 7, and 9 is a sensor cover 8 that communicates with the lower surface opening 10. The water passage window is formed in the wall surface of the sensor cover 8 and is opened at a plurality of locations at intervals in the vertical direction or at one location corresponding to the number of the liquid level sensors 4 installed in the sensor cover 8. As shown in FIG. 9, the liquid level sensor 4 is a photoelectric liquid level sensor in which a light emitting element and a light receiving element are arranged in parallel at a predetermined interval and are opposed to one surface 11 a of the prism 11. While the back surfaces 11b and 11c are exposed to the air, an optical signal emitted from the light emitting element is refracted in the prism 11 and reaches the light receiving element, and the convex back surfaces 11b and 11c of the prism 11 enter the translucent liquid. By submerging, the optical signal from the light emitting element is transmitted through the prism 11 and does not reach the light receiving element. The photoelectric liquid level sensor 4 is mounted from the inside of the sensor cover 8 toward the water flow window 9. An attachment holder 12 is connected to the upper portion of the sensor cover 8 and fixed to the upper surface of the outer cover 7. The control device 5 and the like are built in the hollow portion, and the resin mold 13 is provided in the attachment holder 12. To give a strong watertight structure.
[0009]
The base portion 12a of the mounting holder 12 is formed in a mounting portion that overlaps with the power cord outlet 14 on the upper surface of the outer cover 8, as shown in FIGS. 2 to 4, for example, and is pulled out from the control device 5 to the mounting portion. A structure in which a lead-out hole 16 for vertically guiding the power cord 15 is provided while the wire is led down is provided. Further, as shown in FIGS. 5 and 6, the base 12a of the mounting holder 12 is superposed with the lead wire outlet 17 from the motor protection switch 6 that is drilled at a position different from the power cord outlet 14. It is good also as a structure which is formed in a part, the upper surface of this attachment part is obstruct | occluded, and the lead-out hole 18 for guiding the leader line from the said control apparatus 5 is opened in the lower surface. Reference numeral 19 denotes a fixing bolt for fixing the base portion 12a, and 20 denotes a terminal block for connecting the lead wires in a predetermined manner.
[0010]
[Action]
If the liquid level in the pump installation tank rises and the prism 11 is submerged in the liquid, the optical path is turned off and a liquid level detection signal is output. If the prism 11 is exposed to the air as the liquid level falls, the optical path is turned on. The liquid level detection signal is not output, and if the temperature sensor 3 is turned ON due to abnormal heat generation of the motor, the abnormal heat detection signal is output, and the pump is automatically operated based on switching of these detection signals. . As shown in the flowchart of FIG. 10, when the three-phase AC power supply 1 is turned on and no detection signal is output from the temperature sensor 3 and the detection signal of the liquid level sensor 4 is output, the pump starts operation. However, even if the pump is in an operating state, the pump automatically stops if a detection signal is output from the temperature sensor 3 due to abnormal heat generation of the motor. Further, if the liquid level is lowered due to the drainage action of the pump and the detection signal from the liquid level sensor 4 is not output, the pump automatically stops when the liquid level is lowered to a predetermined liquid level.
[0011]
In this way, the pump is operated and stopped according to the elevation of the liquid level in the pump installation tank and the heat generation state of the motor, but the sensor cover through the water flow window 9 and the lower surface opening 10 is synchronized with the elevation of the liquid level. As the liquid introduction / drainage into and from the inside is repeated, exhaust from the inside of the sensor cover 8 is not performed to form an air reservoir, so that the sensor cover 8 coincides with the liquid level change in the pump installation tank. The liquid level in the inside is smoothly changed, and combined with the wave preventing effect by the wall surface of the sensor cover 8, accurate liquid level detection without malfunction is performed. Further, during maintenance, the state of the prism reflection surface can be easily inspected visually from the water flow window 9, and when an adhering matter is visually recognized on the prism reflection surface, the sensor cover 8 can be directly removed without removing the sensor cover 8. The prism surface can be cleaned.
[0012]
【The invention's effect】
According to the automatic operation device for the submersible electric pump according to the present invention, the motor protection and the automatic operation control are performed by one kind of opening / closing mechanism, so that the installation space in the motor is small, and the pump body is lightweight and compact. It helps directly. In addition, since the circuit is configured to open and close the secondary neutral point of the motor winding by delta connection, as a result of reducing the current flowing through the switching mechanism itself, a switching mechanism with a small contact capacity can be used, and the pump body It will be indirectly useful for lighter and more compact. If the contact capacity of the switching mechanism is not reduced, it is possible to control an output motor that is one rank higher, for example, an output of 7.5 kW for a 2-pole motor and an output of 5.5 kW for a 4-pole motor. Thus, it is possible to control the submersible electric pump that could not be controlled unless it was a separate control panel. Furthermore, as described above, as an advantage of the circuit configuration that opens and closes at the neutral point on the secondary side of the motor winding, the automatic / non-automatic conversion of the submersible electric pump can be easily performed by installing the detachable automatic driving device. It can be done. .
[0013]
Further, in the automatic operation device for the submersible electric pump according to the present invention, since the photoelectric liquid level sensor is used as the liquid level sensor, the movable part of the movable part is different from the conventional one using the float type liquid level sensor. It does not cause operation failure or lead wire damage, and functions effectively in non-conductive liquid unlike conventional ones that use an electrode-type liquid level sensor. Accurate liquid level detection without malfunction due to the wave-breaking effect and flow through the sensor cover is performed, and the status of the prism surface can be easily inspected visually from the water window, and also adhered to the prism reflection surface Can be directly cleaned from the water flow window without removing the sensor cover, and has the advantage of excellent maintainability.
[Brief description of the drawings]
FIG. 1 is an electric circuit diagram of an automatic driving device according to the present invention, and shows an example in which a contactless power device is used for an opening / closing mechanism.
FIG. 2 is a longitudinal side view of a main part of a submersible electric pump provided with an automatic driving device according to the present invention, showing an example in which a mounting holder base is mounted by overlapping with a power cord outlet on a pump outer cover.
3 is a longitudinal side view of a sensor cover portion and a mounting holder portion of the automatic driving device in FIG. 2. FIG.
4 is an external side view of the submersible electric pump shown in FIG. 2. FIG.
FIG. 5 is a longitudinal sectional side view of an essential part of the submersible electric pump provided with the automatic driving device according to the present invention, and is superposed on the outlet of the lead wire from the protective switch on the outer cover of the pump to mount the mounting holder base An example of wearing is shown.
6 is a longitudinal side view of a sensor cover portion and a mounting holder portion of the automatic driving device in FIG. 5. FIG.
FIG. 7 is a plan view of a mounting portion in the automatic driving device according to the present invention.
FIG. 8 is a front view of a sensor cover in the automatic driving apparatus according to the present invention.
FIG. 9 is an explanatory diagram showing the optical path formation of the optical signal of the photoelectric liquid level sensor in the automatic driving apparatus according to the present invention.
FIG. 10 is a flowchart of submersible electric pump operation by the automatic driving apparatus according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Three-phase alternating current limit 2 Motor winding 3 Temperature sensor 4 Photoelectric liquid level sensor 5 Control apparatus 6 Opening and closing mechanism 7 Outer cover of submersible electric pump 8 Sensor cover 9 Water flow window 10 Lower surface opening 11 Prism

Claims (3)

Using a three-phase induction motor as a prime mover for the submersible electric pump, a temperature sensor for detecting abnormal heat generation of the motor, a liquid level sensor for detecting fluctuations in the liquid level, and pump operation based on detection signals from these sensors. A control device for control and an open / close mechanism for connecting or disconnecting the secondary neutral point of the motor winding to or from the delta connection circuit are incorporated in the electric circuit of the motor to protect and automatically operate the motor. In the automatic operation device of the submersible electric pump having the control function combined with the opening / closing mechanism, the liquid level sensor is composed of a photoelectric liquid level sensor arranged in parallel so that the light emitting element and the light receiving element are opposed to one surface of the prism. The sensor cover has a water passage window drilled to communicate with the opening on the wall surface of the sensor cover guided along the outer cover of the submersible electric pump. Characterized in that said photoelectric type liquid level sensor facing the window is mounted, an automatic operation system for water electric pump. 2. The submersible electric pump automatic operation device according to claim 1, wherein the opening / closing mechanism incorporated in the electric circuit of the motor is a contactless power device. 2. The submersible electric pump automatic operation device according to claim 1, wherein the switching mechanism incorporated in the electric circuit of the motor is a mechanical switch having a contact point.

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