Air purifier

• US 6,660,070 B2
• Filed: 11/30/2001
• Issued: 12/09/2003
• Est. Priority Date: 05/04/1999
• Status: Expired due to Fees

• Current Assignee: Simatelex Manufactory Company Limited
• Original Assignee: Simatelex Manufactory Company Limited
• Inventors: Chan, Stephen Wai-Kin, Li, Wing-Chung, Chung, Chi Cheung
• Primary Examiner(s): Copenheaver, Blaine
• Assistant Examiner(s): PHAM, MINH CHAU THI
• Application Number:
  US09/998,146
• Publication Number:
  US 20020078830A1
• Time in Patent Office: 739 Days
• Field of Search: 554/67, 554/72, 554/73, 553/852, 55D/IG.34, 95/25, 95/26, 964/17, 964/24, 963/97, 964/21, 964/22
• US Class Current: 96/424
• CPC Class Codes: B01D 46/0086 Filter condition indicators
• CPC Class Codes: B01D 46/442 by measuring the concentration of particles
• CPC Class Codes: B01D 46/46 automatic
• CPC Class Codes: B01D 46/88 Replacing filter elements
• CPC Class Codes: F24F 11/30 for purposes related to the operation of the system, e.g. for safety or monitoring
• CPC Class Codes: F24F 11/39 Monitoring filter performance
• CPC Class Codes: F24F 11/74 for controlling air flow rate or air velocity
• CPC Class Codes: F24F 11/77 by controlling the speed of ventilators
• CPC Class Codes: F24F 2110/50 Air quality properties
• CPC Class Codes: Y02B 30/70 Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating
• CPC Class Codes: Y10S 55/34 Indicator and controllers

Abstract

An air purifier includes a cabinet, an electrically driven fan, a replaceable filter element, and an air quality sensor. A display provides a visual indication of the air quality condition. A microprocessor is programmed to control the speed of the fan automatically according to the air quality condition. The microprocessor also computes when the filter element must be changed by totalling the time of operation and its speed (which equals air quality) so that for example the filter element will be changed more often (used for less aggregate time) when the air purifier is operated in a poor quality environment.

Claims

1. An air purifier comprising:

a cabinet,

a replaceable filter mounted in the cabinet,

an electrically driven fan arranged to draw air through the filter,

an air quality sensor arranged to detect particles in the air, and

a programmed microcomputer arranged to alter the speed of the fan in accordance with signals generated by the air quality sensor in a manner such that the fan speed is increased when the air quality condition is poor or deteriorates, the fan speed is decreased when the air quality condition is good or improves, and the fan is automatically turned off whenever the number of particles per cubic foot of air is in the range 0 to 2200.

2. An air purifier as claimed in claim 1 wherein the air quality sensor is arranged to detect particles equal to or larger than one micrometer in size, and the microcomputer is arranged to turn off the fan automatically whenever the number of said particles per cubic foot of air is in the range of 0 to 2200.

3. An air purifier comprising:

a cabinet,

a replaceable filter mounted in the cabinet,

an electrically driven fan arranged to draw air through the filter,

an air quality sensor arranged to detect particles in the air,

a visual display arranged to provide a visual display indicative of air quality, and

a programmed microcomputer responsive to signals from the air quality sensor to cause the visual display to indicate air quality, and to alter the speed of the fan in accordance with the indicated air quality in a manner such that the fan speed is increased when the air quality condition is poor or deteriorates, the fan speed is decreased when the air quality condition is good or improves, and the fan is automatically turned off whenever the number of particles per cubic foot of air is in the range of 0 to 2200.

4. An air purifier comprising:

a cabinet,

a replaceable filter mounted in the cabinet,

an electrically driven fan arranged to draw air through the filter,

an air quality sensor arranged to detect particles in the air,

a visual display arranged to provide a visual indication when the filter should be replaced, and

a programmed microcomputer arranged to alter the speed of the fan in accordance with signals generated by the air quality sensor and to cause the visual display to indicate that the filter should be replaced, said indication being caused when a fan total running time value equals or exceeds a predetermined value, the fan total running time value being incremented according to the formula Tn+1=Tn+a X t, wherein Tn is the fan total running time, a is a fan speed factor and t is the fan operating time at speed factor a.

5. An air purifier as claimed in claim 4 wherein the fan total running time value is incremented each time the microcomputer changes the fan speed.