Safety circuitry for ion generator

• US 6,088,211 A
• Filed: 06/24/1998
• Issued: 07/11/2000
• Est. Priority Date: 11/10/1997
• Status: Expired due to Fees

• Current Assignee: Illinois Tool Works Inc.
• Original Assignee: Illinois Tool Works Inc.
• Inventors: Pitel, Ira J.
• Primary Examiner(s): FLEMING, FRITZ M
• Application Number:
  US09/103,796
• Time in Patent Office: 748 Days
• Field of Search: 361/212, 361/213, 361/225, 361/229, 361/230, 361/231, 361/235, 250/324-326
• US Class Current: 361/212
• CPC Class Codes: H01T 23/00 Apparatus for generating ions to be introduced into non-enclosed gases, e.g. into the atmosphere
• CPC Class Codes: H05F 3/04 by means of spark gaps or other discharge devices devices providing for corona discharge per se H01T19/00

Abstract

A capacitor is serially-connected to apply alternating line signal to ion generators that are normally operable on alternate half cycles of line signal for safely inhibiting further operation of a generator of air ions of one polarity in the event a generator of air ions of opposite polarity incurs circuit malfunction. In an alternative embodiment, serially-connected capacitor are shunted by serially-connected diodes poled for unidirectional conduction in opposite directions, with junctions of capacitors and diodes connected together. Conduction of alternate half cycles of AC line signal conducted through such diode-capacitor network during circuit failure of one of the air ion generators to operate properly on the respective alternate half cycle of the AC line signal causes build up of accumulated charge and voltage across one capacitor with a polarity that significantly reduces the average voltage applied to the other, operational air ion generator during each respective alternate half cycle of AC line signal.

Claims

1. A method for providing fail-safe operation of an air ionizer operable to produce positive and negative air ions on respective alternate half cycles of alternating power-line signal, the method comprising:

serially connecting a capacitive element to conduct alternating power-line current therethrough to the air ionizer during normal operation of the air ionizer on respective alternate half cycles, and for storing charge therein of one polarity under conditions of circuit malfunction of the air ionizer to produce one of positive and negative air ions, said one polarity being opposed to polarity of an alternate half cycle of power-line signal during which the air ionizer produces the other of positive and negative air ions for inhibiting production of said other positive and negative air ions.

2. The method according to claim 1 wherein connecting the capacitive element includes serially connecting a pair of capacitors, and shunting the serially-connected pair of capacitors with serially-connected diodes poled in opposite directions of conductivity with common connections of serially-connected diodes and serially-connected capacitors connected together.

3. Apparatus for controlling operation of a pair of circuits which produce a combined utilizable output having selected electrical parameters under normal operation on an alternating signal applied thereto, the apparatus comprising

a first circuit in the pair of circuits which operates on a positive half-cycle of the alternating signal applied thereto in order to produce a portion of the combined utilizable output;

a second circuit in the pair of circuits which operates on a second and opposite half-cycle of the alternating signal applied thereto in order to produce another portion of the combined utilizable output; and

circuitry including a pair of serially coupled capacitors and a pair of diodes serially connected in polarity opposition in parallel with the serially coupled pair of capacitors, with junctions of the serially coupled capacitors and the serially connected diodes coupled together for providing the alternating signal to the pair of circuits to operate the first circuit normally on current drawn thereby during the positive half-cycle of the alternating signal and to operate the second circuit normally on current drawn thereby during the second and opposite half-cycle of the alternating signal, said circuitry inhibiting the drawing of current by either one of the first and second circuits in response to failure of the other of the first and second circuits to draw current during abnormal operation.

4. Apparatus according to claim 3 wherein the first circuit is a generator of air ions of one polarity, and the second circuit is a generator of air ions of opposite polarity.