JP2001082377A - Automatic operation device for submerged motor-driven pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an automatic operation device for a submerged motor- driven pump to dispense with lead-out of the lead wire of a float by a long length even when a control width of a liquid level is high, be stabilized in float inclination operation, and perform high-precise control of a liquid level by a single float type level sensor. SOLUTION: An automatic operation circuit 3 for a pump motor M is contained in a holding body 1 for a float type level sensor 2, the holding body 1 is mounted on a pump P, the pump motor M is started by a starting level detecting signal through upward inclination operation of a float type level sensor 2 during a rise of a liquid level. Based on a time t1 required for detection of a switch liquid level detecting signal through downward inclination operation of the level sensor 2 due to lowering of a liquid level after the staring of the pump motor M, a time t2 required for lowering to a given stop liquid level L is computed. Operation of the pump motor M is continued within the limits of the computed time t2, and a circuit is set such that the pump motor is stopped because of a time being up.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic operation device for a submersible electric pump.

[0002]

2. Description of the Related Art Conventionally, liquid level detection for automatic operation of a submersible electric pump employs a direct detection method in which a control position and a sensor position are set at the same height position. It is customary to use two upper and lower liquid level sensors for detection and stop liquid level detection. Therefore, in the float type liquid level sensor, it is necessary to change the installation interval between the upper and lower sensors or adjust the length of the lead wire in each case according to the control width of starting and stopping the pump motor, and If the control width is large, a float lead wire length that can cover the control width is required. However, if the lead wire is long, the float tilting operation becomes unstable, and the ON / OFF of the internal electric opening / closing mechanism is performed. Switching may not be performed properly, and lead wires may be entangled.

An ON signal for starting the pump motor is given by a liquid level sensor, and a stop signal is given by the sensor.
There is also a system in which the operation is continued for a certain period of time with the timer after the detection of the FF signal, and then the operation is stopped. However, highly accurate liquid level control cannot be performed.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to eliminate the necessity of extending the lead wire of a float even when the control width of start / stop is large, to stabilize the float for tilting operation, and to achieve accuracy without causing entanglement of the lead wire. An object of the present invention is to provide an automatic operation device of a submersible electric pump that can perform high liquid level control with a single float type liquid level sensor.

[0005]

In the apparatus for automatically operating a submersible electric pump according to the present invention, the holder for the liquid level sensor is mounted on the upper part of the submersible electric pump, and the automatic operation circuit for the pump motor is installed in the space inside the holder. The liquid level sensor is a single float type liquid level sensor that transmits a detection signal by switching the contact point of the internal electric opening / closing mechanism to ON-OFF by tilting movement of the float due to fluctuation of the liquid level, The automatic operation circuit has a control circuit unit and an opening / closing unit equipped with a microcomputer. When the liquid level in the pump installation tank rises, the pump motor starts with the liquid level detection signal by the upward tilt operation of the float type liquid level sensor, and the pump motor After the start-up of the liquid level, the liquid level is switched by the downward tilt operation of the liquid level sensor due to the liquid level drop. Based on the time required until the detection of the liquid level detection signal, the predetermined stop liquid level is determined in advance. Calculates the time required for lowering,
The circuit is set so that the operation of the pump motor is continued with the calculated time as a limit, and the pump motor stops when the time is up.

[0006]

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

Reference numeral 1 designates a holder from which a liquid level sensor 2 is led out from a leading end portion through a lead wire, and an automatic operation circuit 3 of a pump motor M is provided by utilizing a hollow portion thereof. 1a is formed on a mounting portion to be mounted on the upper surface of the submersible electric pump P, and a lead-out hole 6 for vertically leading the lead wire from the automatic operation circuit 3 and for guiding the power cord 5 is vertically provided in the mounting portion. Have been. In order to mount the holder 1 on the upper surface of the submersible electric pump P, for example, the lead-out hole 6 vertically provided in the holder base 1a is aligned with the power cord outlet 4 and the lead wire from the automatic operation circuit 3 is provided. To the split core wire of the power cord 5 and the motor-side lead wire so as to be separable by a connection tool 7 such as a connection terminal or a terminal block, respectively.
Further, if the power cord 5 is led out from the outlet hole 6 through the plug-like watertight structure 8 and is fixed from the outside of the holder base 1a by a fixing tool such as a tightening bolt, the tip end will be fixed. The holder 1 is mounted on the upper surface of the submersible electric pump P in such a manner as to extend to the side. The automatic operation circuit 3
Has a control circuit section 3a and an opening / closing section 3b mounted on a microcomputer, and the liquid level sensor 2 is an internal electric opening / closing mechanism (not shown) by tilting movement of a float accompanying a change in liquid level.
Is a float type liquid level sensor that transmits a detection signal when its contact is switched to ON-OFF. For example, when the liquid level in the pump installation tank rises, the float operates upward at the starting liquid level L1 to detect the ON signal. By doing so, the pump motor M is started, and when the liquid level in the tank drops due to the drainage action of the pump P and reaches the switching liquid level L2, the float operates downward and the OFF signal is detected. The above OF after startup
The time required until the F signal is detected, that is, the time t1 required for the liquid level to drop from the starting liquid level L1 to the switching liquid level L2 due to the drainage action of the pump P is counted, and the time t1 is determined in advance based on the time t1. The time t2 required for the liquid level to drop to the desired stop liquid level L is calculated, and the operation of the pump motor M is continued up to the calculated time t2, and the pump motor M is stopped by the time-up. The circuit is set. Therefore, the drainage operation by the pump P is continued for a certain period of time even after the detection of the OFF signal by the liquid level sensor 2, and the drainage operation by the pump P is stopped at the desired stop level L.

[0008]

According to the automatic operation device of the submersible electric pump according to the present invention, the liquid level detection for the pump motor operation control can be performed by a single float type liquid level sensor. This eliminates the need for changing the installation interval between the upper and lower liquid level sensors and adjusting the lead wire length according to the control width as in the conventional direct detection method. Even when the width is large, there is no need to extend the lead wire of the float for a long time, the tilting operation of the float is stabilized, and there is an effect that highly accurate liquid level control can be performed without fear of causing the entanglement of the lead wire.

[Brief description of the drawings]

FIG. 1 is a vertical sectional side view of a main part of a submersible electric pump having the device of the present invention.

FIG. 2 is a block diagram schematically showing the configuration of the device of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Holder 2 Float type liquid level sensor 3 Automatic operation circuit of pump motor 3a Control circuit part 3b Opening / closing part L1 Starting liquid level L2 Switching liquid level L Stop liquid level t1 Reference time for calculation t2 Time calculated M Pump motor P Submersible electric pump

Claims (1)

[Claims] 1. A holding body for a liquid level sensor is mounted on an upper part of an underwater electric pump, and an automatic operation circuit of a pump motor is housed in a space in the holding body. A single float type liquid level sensor for transmitting a detection signal when the contact point of the internal electric opening / closing mechanism is switched ON / OFF by the tilting movement of the float, wherein the automatic operation circuit is a control circuit unit and a switching unit equipped with a microcomputer. When the liquid level in the pump installation tank rises, the pump motor is started by the starting liquid level detection signal by the upward tilt operation of the float type liquid level sensor, and after the pump motor is started, the pump level is lowered by the liquid level sensor. Based on the time required to detect the switching liquid level detection signal due to the tilting operation, the time required to descend to a predetermined desired stop liquid level is calculated, and the calculated time is limited. An automatic operation device for a submersible electric pump, wherein a circuit is set so that the operation of the pump motor is continued and the pump motor is stopped when time is up.