JP2002031064A - Water hammering preventing device for motor-driven pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water hammering preventing device for a motor-driven pump capable of preventing occurrence of water hammering without using any flywheel owing to the slow stop function of an inverter, wherein the effect functions effectively even in the event of power failure. SOLUTION: The motor-driven pump 7 is operated by AC waveform prepared by an inverter part 6 using an inverter device 1 including a converter part 3 and inverter part 6, wherein the pump 7 is decelerated and stopped gradually by the slow stop function of the inverter with an operation command switch 5 put off when the pump is stopped as normal operation, and a power supply circuit is provided leading from a DC auxiliary power supply device 8 provided separately to the inverter part via ed in an accumulating power supply 8 via a power changeover switch 10, and thereby in the event of power failure, the power changeover switch 10 is put on so that the DC auxiliary power is supplied, while the operation command switch 5 is put off so that the pump 7 is decelerated and stopped gradually by the slow stop function of the inverter.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water hammer prevention device for a power supply pump.

[0002]

2. Description of the Related Art Conventionally, as a countermeasure against water hammer of an electric pump, a method has been generally adopted in which a flywheel is mounted on a pump shaft so as to increase a moment of inertia and prevent a sudden stop. I was
However, according to this method, a large-diameter and heavy-weight flywheel is necessary to obtain a sufficient moment of inertia, which inevitably increases the size and weight of the pump and complicates the structure. This is a factor in prolonging the manufacturing period and increasing costs.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a water hammer prevention device for an electric pump which does not require a flywheel to be mounted and does not increase the size and weight of the pump. Another object of the present invention is to provide a water hammer prevention device for an electric pump, which functions effectively even when the main power supply is cut off such as during a power failure.

[0004]

According to the water hammer prevention device for an electric pump according to the present invention, in the invention according to the first aspect, a converter section and a smoothing capacitor for generating a DC power supply by turning on an AC main power supply in an inverter device; An inverter that generates an AC waveform when the switch is turned on has an inverter unit, and the electric pump that is operated with the AC waveform generated by the inverter unit gradually turns off the operation command switch according to a preset deceleration rate according to a slowdown stop function of the inverter. It was configured to be decelerated and stopped. In the invention of claim 2,
The inverter unit has a converter unit and a smoothing capacitor that create a DC power source when the AC main power is turned on, and an inverter unit that creates an AC waveform when the operation command switch is turned on, and is operated with the AC waveform created by the inverter unit. In the electric pump, a power supply circuit from a separately installed DC auxiliary power supply device to the inverter section via the power supply switch is provided, and the power supply switch is turned off during operation of the electric pump.
The DC auxiliary power is not supplied to the electric pump in the FF state, and the electric pump is gradually decelerated and stopped by the slow stop function of the inverter according to a preset deceleration rate by turning off the operation command switch, and the AC main power is shut off. At times, the power supply switch is turned on, the DC auxiliary power is supplied, the operation command switch is turned off, and the electric pump is gradually decelerated and stopped by the slow stop function of the inverter according to a preset deceleration rate.

[0005]

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

Reference numeral 1 denotes an inverter device, in which a converter unit 3 and a smoothing capacitor 4 for generating a DC power supply when an AC power supply 2 is turned on, and an inverter unit 6 for generating an AC waveform when the operation command switch 5 is closed (ON). Have. Reference numeral 7 denotes an electric pump driven by the AC waveform generated by the inverter unit 6, reference numeral 8 denotes a separately installed DC auxiliary power supply device,
A power supply circuit reaching the inverter section 6 via the power supply switch 10 is configured. Examples of the DC auxiliary power supply device include a lead storage battery, a solar cell, and a fuel cell. Note that the operation command switch 5 and the power switch 1
Switches such as 0 are not limited to those having a contact, and may be those having no contact.

[0007]

When the AC main power supply is turned on, a DC power supply is generated via the converter section 3 and the smoothing capacitor 4 of the inverter device 1, and at the same time, the contact b of the power supply changeover switch 10 is opened (OFF). . Then, for example, when the a-contact of the operation command switch 5 is closed (ON) from an external sequence or the like, the inverter device 1 operates the electric pump 7 by generating an AC waveform from the internal inverter unit 6. Meanwhile, the power switch 10
Is OFF, and no DC auxiliary power is supplied from the DC auxiliary power supply device 8.

In both the first and second aspects of the present invention, when the pump is normally stopped, if the a-contact of the operation command switch 5 is opened (OFF) from an external sequence or the like, the inverter device 1 operates at a preset deceleration rate. , The electric pump 7 is gradually decelerated and stopped to prevent the occurrence of the water hammer phenomenon.

Furthermore, when the AC main power supply 2 is cut off due to a power failure or the like, the power supply changeover switch 10 is turned off.
At N, the DC auxiliary power is supplied from the DC auxiliary power supply device 8, and at the same time, the operation command switch 5 is turned off from an external sequence or the like, and the inverter device 1 gradually uses the DC auxiliary power according to the preset deceleration rate. The electric pump 7 is decelerated and stopped to prevent the occurrence of the water hammer phenomenon.

[0010]

According to the present invention, it is possible to prevent a water hammer when the pump is stopped without using a flywheel, so that the electric pump becomes larger and heavier, and the manufacturing time required for the electric pump is prolonged. In addition, since the water hammer prevention function according to the second aspect of the present invention effectively functions even during a power outage, the present invention has great industrial applicability.

[Brief description of the drawings]

FIG. 1 is a block diagram according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Inverter apparatus 2 AC main power supply 3 Converter part 4 Smoothing capacitor 5 Operation command switch 6 Inverter part 7 Electric pump 8 DC auxiliary power supply device 10 Power supply changeover switch

Claims (2)

[Claims] 1. An inverter device comprising a converter section and a smoothing capacitor for generating a DC power supply by turning on an AC main power supply, and an inverter section for generating an AC waveform when an operation command switch is turned on, wherein an AC waveform generated by the inverter section is provided. A water hammer prevention device for an electric pump, characterized in that the electric pump operated in step (1) is gradually decelerated and stopped by a slow stop function of the inverter according to a preset deceleration rate by turning off an operation command switch. 2. An inverter device comprising a converter and a smoothing capacitor for generating a DC power supply by turning on an AC main power supply, and an inverter for generating an AC waveform by turning on an operation command switch. In the electric pump operated with the waveform, a power supply circuit from the separately installed DC auxiliary power supply device to the inverter section via the power supply switch is added. The power is not supplied to the electric pump, and the electric pump is gradually decelerated and stopped by the slow stop function of the inverter according to the preset deceleration rate by turning off the operation command switch. ON, DC auxiliary power is supplied, and the operation command switch is set to O.
A water hammer prevention device for an electric pump, wherein the electric pump is gradually decelerated and stopped by a slow stop function of an inverter according to a preset deceleration rate.