公开(公告)号：US3581895A

公开(公告)日：1971-06-01

申请号：US3581895D

申请日：1969-02-28

Applicant: HERBERT H HOWARD ,  HENRY R YOUNG ,  JACK A BERG ,  BERNARD BELLINSON ,  MARINE SWIMMING POOL EQUIPMENT

Inventor： HOWARD HERBERT H ,  YOUNG HENRY R ,  BERG JACK A ,  BELLINSON BERNARD

IPC: B01D24/14 ,  B01D29/27 ,  B01D29/38

CPC classification number: B01D24/14 ,  B01D24/44 ,  B01D24/4642 ,  B01D24/4884 ,  B01D29/27

Abstract: A pressure-responsive switch senses the rising back pressure in a sand filter caused by debris collected in the filter, and at a predetermined pressure indicating the need for cleaning the filter, it triggers the reversal of valve means which reverses the flow in the filter and backwashes the debris into a separating tank where the debris is collected from the backwash flow which is then returned to the swimming pool. A timer controls the backwashing interval, at the end of which the valve is again reversed by a reversing mechanism, returning the system to normal filtering operation.