JP2001059490A - Automatic operation device for submersible motor-driven pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an automatic operation device for a submersible motor- driven pump using a three-phase induction motor as a prime mover, allowing the compact formation of an opening/closing mechanism itself assembled in an electric circuit and the light and compact formation of the pump body by using one type of opening/closing mechanism with automatic operation control and motor protecting functions combined for reducing a storage space and ensuring effective function of a liquid level sensor even in a non-conductive liquid. SOLUTION: A temperature sensor 3 for detecting abnormal heat generation in a motor, a photoelectric liquid level sensor 4 for detecting a liquid level and an opening/closing mechanism 6 for moving a secondary side neutral point of a motor winding close to or away from a delta connection circuit are assembled in an electric circuit in a submersible motor-driven pump motor. The opening/closing mechanism 6 has motor protecting and automatic operation control functions combined. The liquid level sensor 4 is of a photoelectric type.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for automatically operating a submersible electric pump using a three-phase induction motor as a prime mover.

[0002]

2. Description of the Related Art An automatic operation device for a submersible electric pump of this type is conventionally provided with an opening / closing mechanism dedicated to control for automatic operation control on a primary side of a motor winding, and a motor winding. The secondary side is provided with an opening / closing mechanism dedicated to protection for protecting the motor. In such a circuit configuration, a current equivalent to the current flowing in the main circuit of the submersible electric pump flows through the switching mechanism dedicated to control, so that the contact capacity of the switching mechanism cannot be reduced. Is impossible. In addition, since two types of opening and 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.

In addition, a float type or an electrode type detector is generally used for detecting a fluctuation in the liquid level. The float type type is liable to cause an operational failure or damage to a lead wire in a movable portion. In a liquid having poor conductivity, the detection function is impaired.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a submersible electric pump driven by a three-phase induction motor as a prime mover, with a compact opening / closing mechanism incorporated in its electric circuit and one type of opening / closing mechanism for automatic operation control. The pump can also be used for protecting the motor, making the storage space smaller and lighter and more compact by reducing the storage space. It is an object of the present invention to provide an automatic operation device in which a liquid level sensor functions effectively even in a liquid having a property.

[0005]

According to the present invention, there is provided an automatic operation device for a submersible electric pump according to the present invention, wherein a three-phase induction motor is used as a prime mover of the submersible electric pump, and a temperature sensor for detecting abnormal heat generation of the motor;
A liquid level sensor for detecting liquid level fluctuation, a control device for controlling the operation of the pump based on the detection signals from these sensors, and a secondary neutral point of the motor winding connected to a delta connection circuit. An opening / closing mechanism for separating and disconnecting is incorporated in an electric circuit of the motor, and the function of protection of the motor and an automatic operation control function is also provided in the automatic opening / closing mechanism of the underwater electric pump. Consists of a photoelectric type liquid level sensor in which the light emitting element and the light receiving element are arranged side by side so as to face one surface of the prism. It has a water passage window perforated to communicate with the opening, and the photoelectric type liquid level sensor is mounted facing the water passage window from inside the sensor cover.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments will be described below with reference to the drawings.

In FIG. 1, 1 is a three-phase AC power supply, 2 is a motor winding, 3 is a temperature sensor for detecting abnormal heat generation of the motor, and 4 is a photoelectric type liquid level for detecting fluctuations in the liquid level. A sensor 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 control device for controlling the neutral point on the secondary side of the motor winding according to a control command from the control device 5. It is a switching mechanism for connecting and disconnecting to and from the delta connection circuit. For example, a contactless electronic power device such as a triac is suitable, but a contact mechanical switch may be used.

2 to 8, reference numeral 7 denotes an outer cover of the submersible electric pump, 8 denotes a sensor cover guided downwardly along the outside of the outer cover 7, and 9 denotes the lower opening 1 described above.
A water passage window formed in the wall surface of the sensor cover 8 so as to communicate with the liquid level sensor 4 at one location or at a plurality of locations spaced apart in the vertical direction in accordance with the number of the liquid level sensors 4 mounted in the sensor cover 8. It is opened. As shown in FIG. 9, the liquid level sensor 4 is a photoelectric type liquid level sensor in which a light emitting element and a light receiving element are juxtaposed at a predetermined interval and opposed to one surface 11a of the prism 11. Back 11b, 11
While c is exposed to the air, the light signal emitted from the light emitting element is refracted in the prism 11 and reaches the light receiving element, and the convex rear surfaces 11b and 11c of the prism 11 are immersed in the translucent liquid. Accordingly, the optical signal from the light emitting element passes through the prism 11 and does not reach the light receiving element. Then, the photoelectric type liquid level sensor 4 is attached to the water flow window 9 from inside the sensor cover 8. Reference numeral 12 denotes a mounting holder connected to the upper part of the sensor cover 8 and fixed to the upper surface of the outer cover 7. The hollow part is used to house the control device 5 and the like, and a resin mold 13 is mounted in the mounting holder 12. To make a watertight structure.

The base 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 a lead-out hole 16 for vertically leading the power cord 15 is provided. Also, as shown in FIGS. 5 and 6, the base 12a of the mounting holder 12 is overlapped with the outlet 17 of the lead wire from the motor protection switch 6 provided at a position different from the power cord outlet 14. The mounting portion may be formed in such a manner that the upper surface of the mounting portion is closed and the lower surface is provided with a lead-out hole 18 for guiding the lead wire from the control device 5. 19 is a fixing bolt for fixing the base 12a, 2
Reference numeral 0 denotes a terminal block for connecting the respective lead wires as predetermined.

[0010]

When the liquid level in the pump installation tank rises and the prism 11 is immersed in the liquid, the optical path is turned off and a liquid level detection signal is output. Turns on and 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, an abnormal heat detection signal is output. The pump is automatically operated based on the switching of these detection signals. Let it do. As shown in the flowchart of FIG. 10, the three-phase AC power supply 1 is turned on.
However, if there is no output of the detection signal from the temperature sensor 3 and the detection signal of the liquid level sensor 4 is output, the pump starts operating. However, even if the pump is in operation, if the detection signal is output from the temperature sensor 3 due to abnormal heat generation of the motor, the pump automatically stops. Further, if the liquid level decreases due to the drainage action of the pump and the detection signal from the liquid level sensor 4 is no longer output, the pump automatically stops when the liquid level drops to a predetermined liquid level.

As described above, the pump operates and stops in accordance with the rise and fall of the liquid level in the pump installation tank and the heat generation state of the motor, but is synchronized with the rise and fall of the liquid level through the water passage window 9 and the lower opening 10. As the liquid introduction / drainage into the sensor cover 8 is repeated, the air is not exhausted from the sensor cover 8 to form an air pocket, so that the liquid level in the pump installation tank coincides. The liquid level change in the sensor cover 8 is smoothly performed, and the wave prevention effect by the wall surface of the sensor cover 8 is combined, so that accurate liquid level detection without malfunction is performed. At the time of maintenance, the condition of the prism reflection surface can be easily visually inspected from the water passage window 9, and when an adhering substance is visually recognized on the prism reflection surface, the sensor cover 8 can be directly removed from the water passage window 9 without removing the sensor cover 8. The prism surface can be cleaned.

[0012]

According to the automatic driving device for an underwater electric pump according to the present invention, since the motor protection and the automatic operation control are performed by one kind of opening / closing mechanism, the installation space in the motor can be reduced. This is directly useful for reducing the weight and size of the pump body. Also, since the circuit configuration opens and closes the secondary neutral point of the motor winding by delta connection, the current flowing through the opening / closing mechanism itself is reduced. As a result, an opening / closing mechanism having a small contact capacity can be used, and the pump body can be used. It will be indirectly useful for reducing the size and weight of the product. If the contact capacity of the opening / closing mechanism is not reduced, the output motor can be controlled one rank higher. For example, the output of a 2-pole motor is 7.5 kW, and the output of a 4-pole motor is 5.5 kW.
As described above, it is possible to control a submersible electric pump, which could not be controlled conventionally unless a separate control panel was used. Furthermore, as described above, an advantage of the circuit configuration that opens and closes at the secondary neutral point of the motor winding is that the installation of the detachable automatic operation device makes it possible to easily perform automatic / non-automatic conversion of the submersible electric pump. You can do it. .

Further, in the automatic operation device of the submersible electric pump according to the present invention, since the photoelectric type liquid level sensor is used as the liquid level sensor, it is different from the conventional one using the float type liquid level sensor. It does not cause malfunction of the moving parts or damage to the lead wires, and works effectively even in non-conductive liquid unlike the conventional one using an electrode type liquid level sensor. Accurate liquid level detection without malfunction is performed by the adhesion prevention and wave prevention effect and the flow inside the sensor cover, and the status of the prism surface can be easily visually inspected from the water window and the prism reflection surface Even when the attached matter is visually recognized, it is possible to clean directly from the water passage window without removing the sensor cover, and there is an advantage that maintenance is excellent.

[Brief description of the drawings]

FIG. 1 is an electric circuit diagram of an automatic driving device according to the present invention, showing an example in which a contactless power device is used for an opening / closing mechanism.

FIG. 2 is a longitudinal sectional side view of a main part of a submersible electric pump provided with the automatic operation 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.

FIG. 3 is a vertical sectional side view of a sensor cover portion and a mounting holder portion of the automatic driving device in FIG.

FIG. 4 is an external side view of the submersible electric pump shown in FIG.

FIG. 5 is a vertical sectional side view of a main part of the submersible electric pump provided with the automatic operation device according to the present invention, wherein the mounting holder base is overlapped with the outlet of the lead wire from the protection switch on the outer cover of the pump. Here is an example in which is attached.

6 is a vertical sectional side view of a sensor cover portion and a mounting holder portion of the automatic driving device in 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 device according to the present invention.

FIG. 9 is an explanatory diagram showing formation of an optical path of an optical signal of a photoelectric liquid level sensor in the automatic driving device according to the present invention.

FIG. 10 is a flowchart of the operation of the submersible electric pump by the automatic operation device according to the present invention.

[Description of Signs] 1 Three-phase AC limit 2 Motor winding 3 Temperature sensor 4 Photoelectric liquid level sensor 5 Control device 6 Opening / closing mechanism 7 Outer cover of submersible electric pump 8 Sensor cover 9 Water passage window 10 Lower surface opening 11 Prism

Claims (3)

[Claims] A three-phase induction motor is used as a prime mover of a submersible electric pump, and a temperature sensor for detecting abnormal heat generation of the motor, a liquid level sensor for detecting a liquid level fluctuation, and a detection signal from these sensors. A control device for controlling the operation of the pump based on the motor and an opening / closing mechanism for connecting / disconnecting the secondary neutral point of the motor winding to / from the delta connection circuit in the electric circuit of the motor; In the automatic operation device of the submersible electric pump in which the functions of protection and automatic operation control are also provided in the opening and closing mechanism, a photoelectric type in which the liquid level sensor is juxtaposed to face the light emitting element and the light receiving element to one surface of the prism. A water level window, which is formed of a liquid level sensor and is provided on a wall surface of the sensor cover which is guided along the outer cover of the submersible electric pump in an opening shape on the lower surface so as to communicate with the opening; An automatic operation device for a submersible electric pump, wherein the photoelectric type liquid level sensor is mounted facing a water flow window from inside a bar. 2. The automatic operation device for an underwater electric pump according to claim 1, wherein the opening / closing mechanism incorporated in the electric circuit of the motor is a contactless power device. 3. The automatic operation device for an underwater electric pump according to claim 1, wherein the switching mechanism incorporated in the electric circuit of the motor is a mechanical switch having a contact.