Login| Sign Up| Help| Contact|

Patent Searching and Data


Title:
CONTROLLER OF PUMP WATER SUPPLY DEVICE
Document Type and Number:
Japanese Patent JP2001165057
Kind Code:
A
Abstract:

To provide a controller capable of stopping a pump at a minimum flow rate without using a flow switch in a direct feed-type pump water supply device.

The relationship of f=aΔP2+bΔP+c is established between the differential pressure ΔP obtained by subtracting the suction pressure from the pump discharging pressure, and the frequency (f) of a variable speed gear. The frequency fmin in a minimum flow rate is determined by substituting ΔP, and the frequency of the pump is reduced for a predetermined time when the relationship with respect to the actual frequency (f) becomes f<fmin. The control device has a control means for increasing the frequency by the feedback control in a high flow rate as the pressure is lowered, and continuously decreasing the frequency in a low flow rate as the pressure is not lowered, and stopping a pump by making the frequency 0 at the frequency below a predetermined value.


Inventors:
MORIZUMI KOICHI
SHIMOKAWA SEIJI
YASUNAGA TAMIYOSHI
Application Number:
JP35295199A
Publication Date:
June 19, 2001
Filing Date:
December 13, 1999
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
MATSUSHITA ELECTRIC IND CO LTD
International Classes:
F04D15/00; F04B49/06; H02P3/18; (IPC1-7): F04B49/06; F04D15/00; H02P3/18
Attorney, Agent or Firm:
Fumio Iwahashi (2 others)