Electrical ionizer

Abstract

An electrical ionizer comprising a fan (5) for producing a laminar flow of air; a positive ion emitter (6b) for ejecting positive ions into the flow of air; a negative ion emitter (6a) for ejecting negative ions into the flow of air; a positive voltage supply (27) to the positive ion emitter; a negative voltage supply (28) to the negative ion emitter; and a microprocessor (30) for controlling the positive and negative voltages to obtain a desired ion balance in the flow of air. The fan (5) is a crossflow fan, resulting in a highly uniform and laminar beam of air along the entire length of the fan, with reduced gaps in the air flow and consistent velocity of air, improving ion balance. The use of a crossflow fan also enables the operating mechanism to be contained within a simple 'teardrop' profile, and for operative parts of the device, for example the motor, the bearings, and electronics such as printed circuit boards to be housed outside the air flow, thereby eliminating a possible source of contamination of the air flow. For a comparable size of ionizer enclosure, approximately twice the mass flow, at higher velocities, can be generated as a similar conventional device using axial fans, and at reduced noise levels.

Description

technical field [0001] This invention relates to electrical ionisers, and more particularly to ionisers used in "clean rooms" for sensitive electronic equipment components (such as semiconductor equipment, computer components, hard disks, LCDs, etc.). Background technique [0002] Ionizers are commonly used in environments where ions are generated in the air and thereby neutralize surface charges. In most applications, the static charge is reduced to a few hundred volts, which is nominally sufficient to eliminate dust pickup. However, in the electronics industry, especially in clean rooms, electrostatic charges of several hundred volts have a devastating effect on semiconductor devices such as microprocessor chips. In these cases, it is important to ensure that the ionization delivered by the neutralization system is balanced and specifically targeted to the area requiring neutralization. In many applications, static charge growth must be limited to a few volts, possibly +...

AI Technical Summary

Problems solved by technology

This has some benefits for ion balance, but presents problems with control circuitry and additional cost in the overall assembly to achieve balance

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