JP2001059492A - Detachable liquid level detector for automatically operating submersible motor-driven pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the subject detector eliminating the need for a long electrode rod even if the control of a liquid level is in a wide range, formed small in size, superior in mounting stability, and permitting highly precise liquid level control. SOLUTION: An automatic operation circuit 3 of a pump motor M is stored in a holder 1 having an upper liquid level sensor 2A and a lower liquid level sensor 2B opposed to each other at a vertically limited space and a base 1a of the holder 1 is formed on a mounting portion on the upper face of a submersible motor-driven pump. The circuit is set to start the pump motor M by using an ON signal from the upper liquid level sensor 2A while computing a time t2 for a liquid level to be lowered to a predetermined stop level L based on a time t1 required to detect an OFF signal from the lower liquid level sensor 2B after the OFF signal from the upper liquid level sensor 2A is detected, so that the pump motor M can be continuously operated within the limits of the computed time t2 and stopped at time-up.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a removable liquid level detector for automatic operation of a submersible electric pump.

[0002]

2. Description of the Related Art Conventionally, a liquid level detection for automatic operation of a submersible electric pump has been performed by a direct detection method in which a control liquid level and a sensor position are set at the same height position. Therefore, when the control width of the start / stop of the pump motor is large, a long electrode rod that covers the control width is required for the lower liquid level sensor, and the detection device becomes large, instability of mounting, There is a problem that it is easily damaged by external impact. In addition, when the detection unit is a detachable unit, in addition to the above-described disadvantages, changing the pump type leads to a change in the electrode length corresponding to the control position of the pump. You have to keep a variety of different kinds. Furthermore, since the stop liquid level is generally near the upper surface of the pump casing, the lower liquid level sensor may interfere with the winding of the pump casing.

There is also a system in which an ON signal for starting a pump motor is given by an electrode, and a stop signal is generated by sending an OFF signal from the same electrode and then stopping for a certain period of time by a timer and then stopping. , The time-up position does not always coincide with the desired stop position that the user originally wants to stop, so that accurate liquid level control cannot be performed.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a small-sized, highly stable mounting unit which does not require a long electrode rod even when the starting and stopping control width is large, and which is subject to external impact. Is small, it is not necessary to change the electrode length depending on the type of pump, and the lower liquid level sensor is short and small, does not interfere with the winding of the pump casing, and performs highly accurate liquid level control. It is an object of the present invention to provide a removable liquid level detector for automatic operation of a submersible electric pump.

[0005]

In the detachable liquid level detector for automatic operation of a submersible electric pump according to the present invention, the upper liquid level sensor and the lower liquid level sensor are opposed to each other with a slight vertical difference. The automatic operation circuit of the pump motor is housed in the body, and the base of the holder is formed in a mounting portion that is attached to and detached from the power cord outlet on the upper surface of the submersible electric pump by a fixing tool. A lead-out hole for leading out the lead wire from the operation circuit is vertically provided, and the lead-out hole is overlapped with the power cord outlet, and the lead wire from the automatic operation circuit is connected to the split core wire of the power cord and the motor-side lead wire. Automatic operation of a submersible electric pump configured to be detachably connected by a connection tool and to attach the holder base to the outlet according to a state in which the power cord is led out from the outlet hole through the watertight structure. for In the landing type liquid level detector, the automatic operation circuit has a control circuit unit and an opening / closing unit mounted on a microcomputer, and the liquid level sensor detects an ON signal when the tip of the electrode rod comes into contact with the liquid and separates the liquid. This is an electrode type liquid level sensor that detects the OFF signal,
When the liquid level rises, the pump motor starts by the ON signal of the upper liquid level sensor.
The time required for the liquid level to drop to a predetermined desired stop level is calculated based on the time required for detecting the OFF signal of the lower liquid level sensor after the detection of the F signal, and the pump is limited to the calculated time as a limit. The circuit is set so that the operation of the motor continues 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.

[0007] P is an automatic submersible electric pump to which the liquid level detecting device of the present invention is attached, and 1 is a holder having an upper liquid level sensor 2A and a lower liquid level sensor 2B led out from the lower surface of the tip, and has a hollow body. The automatic operation circuit 3 of the pump motor M is built in using the part, and the base part 1a of the holder 1 is formed in a mounting part that overlaps with the power cord outlet 4 on the upper surface of the automatic submersible electric pump P. Is provided with a lead-out hole 6 for guiding a lead wire from the automatic operation circuit 3 and leading the power cord 5 upward. The upper liquid level sensor 2
A and the lower liquid level sensor 2B detect the ON signal when the tip of the electrode rod comes into contact with the liquid, and separate the liquid from the ON signal.
This is an electrode type liquid level sensor for detecting the F signal. The two liquid level sensors 2A and 2B are opposed to each other with a slight difference in height in the vertical direction.
The pump motor M is started by the ON signal of the upper liquid level sensor 2A which comes into contact with the liquid at the intermediate liquid level L2 of the lower liquid level sensor 2B after detecting the OFF signal of the upper liquid level sensor 2A which has separated when the liquid level falls. A time t2 required for the liquid level to decrease to a predetermined desired stop level L is calculated based on a time t1 required for detecting the OFF signal by the liquid, and the pump motor M is limited to the calculated time t2 as a limit. Is set so that the pump motor M is stopped by the time-up. The automatic operation circuit 3 has a control circuit section 3a and a switching section 3b mounted on a microcomputer.

In order to equip the non-automatic underwater electric pump P 'as shown in FIG. 1 with the liquid level detecting device of the present invention, each of the split core wires of the power cord 5 is separated from the motor side lead wire, and the power cord 5 is separated. After extracting the state of FIG.
The lead-out hole 6 vertically provided in the holder 1 shown in FIGS. 3 and 4 is aligned with the power cord outlet 4, and the power cord 5 once extracted is used again to draw out from the automatic operation circuit 3. The wires are separably connected to the divided core wire of the power cord 5 and the motor-side lead wire by connecting tools 7 such as connection terminals and terminal blocks, respectively, and the power is supplied from the outlet hole 6 through a plug-like watertight structure 8. If the outside of the holder base 1a is fixed by a fixing tool 9 such as a tightening bolt in a state in which the cord 5 is led out, a liquid level detecting tool is provided in a state in which the front end portion is laterally extended, The non-automatic submersible electric pump P 'is converted to the automatic submersible electric pump P shown in FIGS.

When the automatic submersible electric pump P equipped with the liquid level detector of the present invention is used as a non-automatic type, FIG.
The base 1a of the holder 1 is removed from the outlet 4 as shown in FIG.
When the power cord 5 is led out from the outlet 4 through the watertight structure 8 in a state where the split core wire of the power cord 5 is detachably connected to the motor-side lead wire by the connector 7, FIG.
The non-automatic underwater electric pump P ′ shown in FIG.

[0010]

According to the liquid level detector according to the present invention, even when the control width of starting and stopping of the pump is large, it is formed in a small size without a long electrode rod and has excellent mounting stability. The part that receives external shock is small, and it is not necessary to change the electrode length depending on the type of pump.
Further, the lower liquid level sensor is short and small, does not interfere with the winding of the pump casing, and can perform a high-precision liquid level control.

Furthermore, the present non-automatic underwater electric pump can be used immediately as an automatic underwater electric pump only by attaching the liquid level detecting device of the present invention to the ready-made non-automatic underwater electric pump. There is an advantage that it can be restored.

[Brief description of the drawings]

FIG. 1 is a vertical sectional side view of a main part of a non-automatic underwater electric pump to which a liquid level detecting device according to the present invention is attached.

FIG. 2 is a longitudinal sectional side view showing a state where a power cord is extracted from the non-automatic underwater electric pump of FIG. 1;

FIG. 3 is a vertical sectional side view of a main part of the liquid level detector of the present invention.

FIG. 4 is a plan view of the liquid level detector of the present invention.

FIG. 5 is a vertical sectional side view of a main part of an automatic submersible electric pump constructed by mounting the liquid level detecting device of the present invention from the state of FIG. 2;

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

FIG. 7 is a block diagram showing a configuration of an automatic submersible electric pump equipped with the liquid level detector of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Holder 1a Base 2A Electrode type upper liquid level sensor 2B Electrode type lower liquid level sensor 3 Automatic operation circuit of pump motor 3a Control circuit part mounted with microcomputer 3b Opening / closing part 4 Power cord outlet 5 Power cord 6 Lead-out hole 7 Connecting Equipment 8 Watertight Structure 9 Fixing Equipment M Pump Motor

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F04D 13/16 F04B 49/02 311 F-term (Reference) 3H020 AA01 AA08 BA01 BA02 BA03 BA08 BA11 BA18 CA07 DA01 EA04 EA09 EA12 3H045 AA06 AA09 AA12 AA23 BA24 CA16 CA25 CA29 DA01 EA35 EA38

Claims (1)

[Claims] An automatic operation circuit for a pump motor is accommodated in a holding body in which an upper liquid level sensor and a lower liquid level sensor are vertically opposed with a slight difference in height, and a base of the holding body is underwater. A power supply cord outlet on the upper surface of the electric pump is formed on a mounting portion which is attached to and detached from the fixing tool by being superimposed on the power cord outlet. Is superposed on the power cord outlet, the lead wire from the automatic operation circuit is separably connected to the split core wire of the power cord and the motor-side lead wire by a connector, and the watertight structure is formed from the outlet hole. A detachable liquid level detector for automatic operation of a submersible electric pump configured to mount the holder base on an outlet according to a state in which a power cord is led through the automatic operation circuit. The liquid level sensor is an electrode type liquid level sensor that detects an ON signal when the tip of an electrode rod comes into contact with liquid and detects an OFF signal when liquid is separated from the tip of the electrode rod. Yes, the pump motor is started by the ON signal of the upper liquid level sensor when the liquid level rises, and based on the time required from the detection of the OFF signal of the upper liquid level sensor to the detection of the OFF signal of the lower liquid level sensor when the liquid level falls, The time required for the liquid level to drop to a predetermined desired stop level is calculated, and the circuit is set so that the operation of the pump motor is continued up to the calculated time and the pump motor stops when the time is up. A detachable liquid level detector for automatic operation of a submersible electric pump.