GB2431152A

GB2431152A - An ozone generator

Info

Publication number: GB2431152A
Application number: GB0614756A
Authority: GB
Inventors: Andrew Young
Original assignee: Ozone Industries Ltd
Current assignee: Ozone Industries Ltd
Priority date: 2003-06-14
Filing date: 2003-06-14
Publication date: 2007-04-18
Anticipated expiration: 2023-06-14
Also published as: GB2431152B8; GB2431152B; GB0614756D0

Abstract

An ozone generator system for treating a volume of air comprising a power supply, an ozone generator 12, and a control means, the control means causing the ozone generator to automatically operate at a first production rate for a first time period, and operate at a second different production rate for a second different time period, said production rates and time periods being predetermined. The user may enter or vary the length of the first time period and the second time period. The use may also enter or vary at least one of the production rates.

Description

OZONE GENERATOR CONTROL

Description

The invention relates to the control of ozone production from ozone generators using a timer.

Ozone is a molecular fonn of oxygen containing three oxygen atoms.

Ozone can be generated using several methods, the most common of which is corona discharge. In a corona discharge generator, a high * voltage AC source is connected to two electrodes separated by a dielectric material. The electrodcs and dielectric are arranged in such a way as to create an air boundary at which a corona occurs. When a gas containing oxygen is passed through the corona, ozone is formed from the oxygen. The ozone output from a corona discharge generator can be *:. varied using several methods that are well known in the art, including, duty cycling the power supply or changing the power supply voltage :: : : : and/or frequency.

Ozone is a powerful oxidising agent and this property has led to its use as a disinfectant and deodorising agent. At high concentrations ozone gas is an irritant and occupational exposure standards have been set to limit human exposure. In Europe this limit is generally set at 0. lppm (8 hour time weighted average). Low concentrations of ozone gas (less

I

than 0. lppm) are commonly used to control odours in environments where problem smells can occur, such as washrooms. In order to achieve disinfection of an area, levels of ozone that are much higher than those that can be used safely in the presence of people are required (eg. 2ppm).

In applications where room disinfection is required, for example, a food processing factory, an ozone generator may be operated using an on/off timer. The timer turns the ozone generator on at a time when no people will be present and then turns the generator off several hours before the room is to be occupied in order to allow sufficient time for the ozone to revert back to oxygen. Ozone generators using this type of timer control cannot be used to supply low levels of ozone to the room when people :.:::. are present. * .

:1. An object of this invention is to provide an effective ozone generator * *: system that can be used in a safe manner. S.

According to the present invention, there is provided an ozone generator system for treating a volume of air comprising a power supply, an ozone generator, and a control means, the control means causing the ozone generator to automatically operate at a first production rate for a first time period, and operate at a second different production rate for a second different time period, said production rates and time periods being predetermined.

Preferably a user may enter or vary the length of the first time period and the second time period. Preferably, a user may enter or vary at least one of the production rates.

According to another aspect of the present invention, there is provided a method of treating a volume of air comprising generating ozone at a first production rate for a first time period, and subsequent generating ozone at a second different production rate for a different second period, said production rates and time periods being predetermined.

The timer controls the output of the ozone generator at a low value, or high value, depending on times which are pre-set by the user. The generator can therefore be used to run in a deodorising mode when S...

people are present and a disinfection mode in their absence. S. * S * ...

Preferably the timer is an electronic 24 hour, 7 day timer with its control.

function linked to the power supply circuitry of a corona discharge ozone generator. Preferably, the ozone generator output levels can be mdependently varied.

A preferred embodiment of the invention will now be described with reference to the accompanying drawings in which: Figure 1 is a schematic of the timer and ozone generator.

Figure 2 is a plan view of the exterior of an ozone generator incorporating a timer and two ozone output control knobs.

The mains power supply 1, operating at 23OVAC and 50 Hz, supplies a variable transformer 2. Output voltage from the variable transformer can be tapped from either of two pick-ups 7 or 8. The voltage tapped by pickups can be independently varied by the user from 0 V, corresponding to zero ozone output, to the maximum voltage corresponding to a maximum ozone output, by using control knobs 13 and 14 positioned on the outside of the ozone generator 12. The output from the variable transformer 2 supplies a high voltage step-up transformer 5. The high voltage transformer has a maximum output voltage of approximately 10 000V and this is connected to the ozone generator cell 6. The ozone output from the generator cell is : .*** proportional to the voltage applied to the high voltage transformer 5 from the variable transformer 2.

In a more specific embodiment, the generator cell 6 consists of a sheet * of ceramic dielectric with stainless steel electrodes on opposing faces.

One of the electrodes is connected to the high voltage step-up transformer 5 and the other electrode is connected to ground. Ozone is generated on the edges of the electrodes. A fan is used to pass ambient air over the generator cell and transfer it into the room that is being treated.

The timer 4 is of the type commonly available which allows several "on" and "off' time periods per day to be programmed in by the user. A suitable timer is manufactured by Timeguard Ltd, namely the EMU56.

The timer "on" and "off' periods correspond, respectively, to "high" and "low" output control voltages. The timer can be set by using the function buttons 11 in conjunction with the display screen 10. The "on" and "off' output signals from the timer pass to a switch 3 via a control wire 9. The switch is designed such that the "on" control signal from the tinier causes the circuitry associated with variable transformer 2 pick-up 8 to be enabled. An "off' control signal from the timer causes the switch to enable circuitry associated with the variable transformer pick-up 7.

Hence, the ozone output from the generator 12 changes over time according to whether the timer 4 control signal is "on" or "off'. The ozone production rates during the timer "on" and "off' periods are independently set by using the output knobs 13 and 14 respectively. In an application where the ozone generator is operated in a washroom, the user sets the "on" period of the timer to be when people would not be using the room, for example, from 20-00 hours until 08-00 hours on * each day of the week. The control knob 13 is then adjusted to give a suitable ozone concentration in the room to provide disinfection, for example, 2ppm. The "off' time period on the timer is by default 08-00 hours until 20-00 hours. Ozone output control knob 14 is adjusted to give an ozone output that results in an ozone concentration of less than 0.1 ppm in the room.

The invention claimed herein has been described with respect to a specific embodiment illustrated in the drawings. Many variations on the main embodiment will be obvious to anyone skilled in the art. Ozone can be generated using any of the known methods. Different power supplies can be used, for example 11 OVAC or batteries. The control of the ozone generator output can be achieved by several methods including varying the frequency of the power supply or duty cycling the ozone generator. The ozone output from the generator can be fixed at a maximum value during one time period and be user variable at the other time period. The ozone output can also be adjusted at a fixed ratio between the "high" and "low" settings. * .* * * S **** p... * . S... S. * . * *..

S S.. S. * . * ... p. * * . . * S*

Claims

Claims 1. An ozone generator system for treating a volume of air

comprising a power supply, an ozone generator, and a control means, the control means causing the ozone generator to automatically operate at a first production rate for a first time period, and operate at a second different production rate for a second different time period, said production rates and time periods being predetermined.
2. A system according to claim 1 wherein a user may enter or vary the length of the first time period and the second time period.
3. A system according to either claim 1 or 2 wherein a user may enter or :.:::. vary at least one of the production rates. * *

* ** S
4. A system according to any previous claim wherein the first ozone *:. production rate is such that the concentration of ozone in the volume of air to be treated remains below approximately 0.3 parts per million.

*
5. A system according to any previous claim wherein the first ozone production rate is such that the concentration of ozone in the volume of air to be treated remains below approximately 0.1 parts per million.
6. A system according to any of claims 1 to 3 and claim 5 wherein the second ozone production rate is such that the concentration of ozone in the volume of air to be treated rises to a maximum of approximately 0.2 parts per million.
7. A system according to any previous claim wherein the second ozone production rate is such that the concentration of ozone in the volume of air to be treated rises to a maximum of approximately 1 part per million.
8. A system according to any previous claim wherein further time periods and ozone production rates may be set by the control means.
9. A system according to any previous claim wherein the first ozone production rate and the second ozone production rate can be simultaneously varied in a fixed ratio by the user when setting the ::::. control means. * * **..
10. A system according to any previous claim wherein the first and * second ozone production rates are produced by tapping different voltages from a transformer connected to the power supply.

*
11. A system according to any of claims 1 to 9 wherein the first and second ozone production rates are produced by applying a first and second duty cycle to the ozone generator.
12. A method of treating a volume of air comprising generating ozone at a first production rate for a first time period, and subsequent generating ozone at a second different production rate for a different second period, said production rates and time periods being predetermined.
13. A method according to claim 12 wherein the first ozone production rate is such that the concentration of ozone in the volume of air to be treated remains below approximately 0.3 part per million.
14. A method according to either claim 12 or 13 wherein the first ozone production rate is such that the concentration of ozone in the volume of air to be treated remains below approximately 0.1 part per million.
15. A method according to any of claims 12 or 13 wherein the second ozone production rate is such that the concentration of ozone in the a...

* volume of air to be treated rises to a maximum of approximately 0.2 parts per million.

S a..
16. A method according to any of claims 12 to 15 wherein the second * : : ; ozone production rate is such that the concentration of ozone in the volume of air to be treated rises to a maximum of approximately 1 part per million.
17. An ozone generator system and method substantially as herein described and illustrated.