Filter life indicator for water purification system using magnetically actuated switch

• US 5,236,578 A
• Filed: 07/07/1992
• Issued: 08/17/1993
• Est. Priority Date: 07/07/1992
• Status: Expired due to Fees

• Current Assignee: American Home Products Corporation (Pfizer Inc.)
• Original Assignee: American Home Products Corporation (Pfizer Inc.)
• Inventors: Meyer, James D., Browne, Evan P., Oleskow, Brett J.
• Primary Examiner(s): Drodge, Joseph W.
• Application Number:
  US07/909,608
• Time in Patent Office: 406 Days
• Field of Search: 210/85, 210/87, 210/88, 210/89, 210/138, 210/143, 210/192, 210/259, 340/606, 340/609, 340/611, 340/825.65, 73/861.63, 73/861.08, 200/81.9 M, 200/82 E
• US Class Current: 210/87
• CPC Class Codes: B01D 61/08 Apparatus therefor
• CPC Class Codes: B01D 61/081 used at home, e.g. kitchen
• CPC Class Codes: B01D 61/12 Controlling or regulating
• CPC Class Codes: C02F 2209/445 Filter life
• CPC Class Codes: G01F 1/24 with magnetic or electric coupling to the indicating device
• CPC Class Codes: G01P 13/002 with electrical coupling to the indicating devices

Abstract

A filter life indicator is described herein utilizing a constant flow channel and a flow actuated switch incorporating a reciprocating magnetic member to start a timer. Circuitry monitors this timer and actuates a visual or audible indicator when the filter needs to be replaced. The timer consists of a pulse generator, a scaling circuit, a counter, and a comparator. During flow pulses are counted and compared to a preset limit. And to accommodate filters having differing life expectancy, modules corresponding to each filter are installed to change the scaling circuit.

Claims

1. In a water filtering system connected to a water line having means to selectively control the flow of water through a defined channel of flow, the improvement comprising:

switch means actuated by said flow for detecting said flow, said switch means comprising a magnetic member restrained in the channel of flow for reciprocal motion responsive to said flow and a magnetically operated switch positioned proximate said magnetic member for actuation thereby, wherein said magnetic member is constrained for reciprocal motion within said channel of flow; and

circuit means coupled to said switch means for timing the duration of said water flow and providing an indicator signal when a predetermined amount of flow has occurred, said circuit means including pulse generation means, counter means coupled to said pulse generation means for accumulating the count of generated pulses in response to activation by said switch, and comparator means for comparing said count against a predetermined maximum count,

wherein said counter means includes "divide by N" circuitry and a separably replaceable module means for selecting the "N" factor and for selectively scaling said generated pulses.

2. The water filtering system of claim 1 wherein said replaceable module means comprises predetermined jumper connections.

3. In a water filtering system connected to a water line having means to selectively control the flow of water through a defined channel of flow, the improvement comprising:

switch means actuated by said flow for detecting said flow, said switch means comprising a magnetic member restrained in the channel of flow for reciprocal motion responsive to said flow and a magnetically operated switch positioned proximate said magnetic member for actuation thereby, wherein said magnetic member is constrained between a constriction in said channel of flow and a fixed repelling magnet positioned within said channel of flow; and

circuit means coupled to said switch means for timing the duration of said water flow and providing an indicator signal when a predetermined amount of flow has occurred, said circuit means including pulse generation means, counter means coupled to said pulse generation means for accumulating the count of generated pulses in response to activation by said switch, and comparator means for comparing said count against a predetermined maximum count.

4. The water filtering system of claim 3 wherein said counter means includes "divide by N" circuitry and a replaceable module for selecting the "N" factor, for selectively scaling said generated pulses.