WO2019016721A1

WO2019016721A1 - Fluid purification

Info

Publication number: WO2019016721A1
Application number: PCT/IB2018/055333
Authority: WO
Inventors: Jacobus Frederik ELS; Wolfgang Hunck
Original assignee: Els Jacobus Frederik
Priority date: 2017-07-19
Filing date: 2018-07-18
Publication date: 2019-01-24

Abstract

The invention provides a sterilizer, which includes a gas discharge lamp arranged to produce radiation in the ultra violet frequency range of between 100nm and 280nm, a conductive terminal spaced from the gas discharge lamp, and a translucent fluid conduit disposed at least partially between the gas discharge lamp and the conductive terminal, the conduit permitting a fluid to flow between the gas discharge lamp and the conductive terminal. The sterilizer further includes a high voltage source which has a high voltage pulsed output and a high voltage direct current output. Two terminals of the gas discharge lamp are connected to the high voltage pulsed output to create a pulsed signal at the terminals of the gas discharge lamp. The conductive terminal is connected to the high voltage direct current output of the high voltage source such that a high voltage electrical field is created over the isolated fluid conduit.

Description

Fluid Purification

FIELD OF THE INVENTION

The present invention relates to fluid purification. In particular, the invention relates to a sterilizer.

BACKGROUND OF THE INVENTION

Generally, water purification techniques comprise the passing of water through a multitude of filters. Different filters are available in the market, including those to remove particulate or macromolecule matter, charcoal-based chlorine filters, and the like. Moreover, it is known that ultraviolet (UV) radiation plays a dual role in the advanced oxidative process of water purification. Firstly, UV light can split water (H2O) to produce hydroxyl radicals (OH), a highly reactive species which causes the oxidation of other species, thereby decomposing them. Secondly, UV light causes, the creation of thymine dimers in the nuclear material of living organisms, preventing DNA replication. For these reasons, UV often forms an integral part of water purification systems relying on advanced oxidative processes.

One disadvantage of existing mechanical water purification systems is that filters rely on hardware which can get clogged up by particulate matter and the like. This negatively impacts the efficacy of the filter, especially with regards to destroying living contaminants, which may escape the oxidative process and be ingested by a consumer. This problem may be addressed by regular replacement of filters - a process which is often expensive and delayed or forgotten by the consumer.

The inventors are aware of current water purification systems and have identified a means of overcoming the shortcomings they present. The invention aims to provide an improved design for a water sterilizer which enhances the oxidation process and effectively destroys all living contaminants, producing drinking water safe for human consumption. Moreover, the invention does not include any replaceable parts, minimizing the expense and effort required by the consumer.

SUMMARY OF THE INVENTION

According to a first aspect of the invention, there is provided a sterilizer, which includes

a gas discharge lamp arranged to produce radiation in the ultra violet frequency range of between 100nm and 280nm;

a conductive terminal spaced from the gas discharge lamp;

a translucent fluid conduit disposed at least partially between the gas discharge lamp and the conductive terminal permitting a fluid to flow between the gas discharge lamp and the conductive terminal;

a high voltage source having a high voltage pulsed output and a high voltage direct current output, two terminals of the gas discharge lamp connected to the high voltage pulsed output to create a pulsed signal at the terminals of the gas discharge lamp, and the conductive terminal connected to the high voltage direct current output of the high voltage source such that a high voltage electrical field is created over the isolated fluid conduit.

The gas discharge lamp may be a fluorescent lamp. The fluorescent lamp may be selected from any one of a low pressure lamp and a high pressure lamp. The conductive terminal may be in the form of a sheath disposed at least partially around the gas discharge lamp. The sheath may define at least a partial Faraday cage around the gas discharge lamp.

The translucent fluid conduit may define a di-electric between the gas discharge lamp and the conductive terminal.

In one embodiment of the sterilizer the translucent fluid conduit may e a cylindrical fluid conduit, the gas discharge lamp may be a low pressure tubular lamp disposed co-axially in the cylindrical fluid conduit, and the conductive terminal may be a metal sheath around the cylindrical conduit.

In one embodiment the high voltage source may comprise an alternatively pulsed MOSFET driving circuit connected to a centre-tap, push-pull, step-up transformer, the high voltage pulsed output of the high voltage source being the output of the step-up transformer.

The high voltage source may further include a voltage multiplier arranged in a Cockroft-Walton arrangement of diodes and capacitors, the high voltage direct current output of the high voltage source being the output of the voltage mulitplier.

The high voltage pulsed output and the high voltage direct current output of the high voltage source may share a common terminal. One terminal of the gas discharge lamp may be connected to the common terminal.

The high voltage source may include a resonant circuit. The resonant circuit may be an LC resonant circuit at the input of the step-up transformer. The step-up transformer, the gas discharge lamp, the conductive terminal and a fluid within the translucent fluid conduit may form part of the resonant circuit.

The resonant circuit may include capacitors at the high voltage pulsed output of the high voltage source.

The alternatively pulsed MOSFET driving circuit may be frequency adjustable. The alternatively pulsed MOSFET driving circuit may be frequency adjustable between 68KHz and 82KHz. The output voltage of the centre-tap, push-pull, step-up transformer may be about 900V.

The output voltage of the voltage multiplier may preferably exceed

10KV. The in-circuit rise-time of the alternatively pulsed MOSFET driving circuit may preferably be less than 5nS 200ns. The invention is now described, by way of non-limiting example, with reference to the accompanying figures.

FIGURES In the figures:

Figure 1 shows a water sterilizer in accordance with one aspect of the invention; and

Figure 2 shows one embodiment of the water sterilizer of Figure 1 with a high voltage source connected to the high voltage sheath; and

Figure 3 shows an improved high voltage source which is connectable to the water sterilizer of Figure 1 .

In the figures, like reference numerals denote like parts of the invention unless otherwise indicated.

EMBODIMENT OF THE INVENTION

In the figures, reference numeral (10) refers to a water sterilizer. The water sterilizer (10) has a tubular water conduit (12) which is closed at both ends (12.1 , 12.2) with a water inlet (12.3) and a water outlet (12.4). The water conduit (12) is manufactured from an electrical insulator material, such as glass, Perspex™ or the like.

An ultraviolet (UV) lamp (14) is located centrally on the longitudinal axis of the tubular water conduit (12), such that water (not shown) in the conduit is exposed to radiation from the UV lamp (14) in use. Electrical connections (14.1 to 14.4) are provided on the electrical terminals of the UV lamp (14). The UV lamp (14) is selected to emit ultraviolet radiation with a wavelength of between 100nm and 400nm. In this example, the UV lamp (14) is selected to emit UVC light with a wavelength of between 100nm and 280nm.

A tubular, high voltage sheath (16) is provided around the tubular water conduit (12). The high voltage sheath (16) is in the form of a metallic sheath. As can be seen in Figure 1 , the UV lamp (14), the tubular water conduit (12) and the metallic sheath (16) are arranged co-axially to each other.

In this example, an electrically conductive coil (18) is arranged in a helix around the metallic sheath (16). As can be seen, the electrically conductive coil (18) is connected to a high voltage source (50) (see Figure 2).

In use, the metallic sheath (16) induces a high voltage electrical field over the water conduit (12). In this example, the high voltage electrical field is approximately 10kV.

The tubular water conduit (12) includes an air intake (12.4) proximate the water inlet (12.3) for receiving air into the water at the inlet (12.3) before passing through the conduit (12) around the UV lamp (14). In this example, in use, the water sterilizer (10) generates ozone inside the water because of the high electric field, as well which helps with the sterilisation of the water.

The water sterilizer (10) includes a water pump (not shown) arranged at any one of the inlet (12.3) or the outlet (12.4) of the tubular water conduit (12) for pumping water through the tubular water conduit (12).

Figure 2 shows another arrangement of the water sterilizer (10) in which the water sterilizer (10) is connected to a high voltage source (50). The high voltage source (50) is connected to the coil (18) of the high voltage sheath (16).

The high voltage source (50) comprises four Power MOSFET transistors (52) arranged in a high frequency oscillation circuit (68) with diodes (54), Zener diodes (56), capacitors (58), resistors (60) and capacitors (62, 64, 66). The high frequency oscillation circuit (68) is connected to an input of a voltage step up transformer (70). An output of the high voltage step up transformer (70) is connected to a voltage multiplier (72) arranged in a Cockroft-Walton arrangement of diodes (74) and capacitors (76). An output of the voltage multiplier (72) is connected to the high voltage sheath (16) around the tubular water conduit (12).

As can be seen, terminals of the UV lamp (14) is connected to a transformer (78) and a capacitor (80).

In use, the high voltage source (50) is operable to generate a direct current at the high voltage sheath (16), thereby creating an electric field over the water in the tubular conduit (12).

In this embodiment, the high voltage sheath (16) is manufactured from aluminium.

Figure 3 shows another embodiment of a high voltage source (100) which is connectable to a water sterilizer (10).

In this embodiment, the conductors 14.1 and 14.2 are connected together and 14.3 and 14.4 are connected together, respectively.

The high voltage source (100) includes a microprocessor (102), which controls the switching sequence of the high voltage source (100). The microprocessor (102) checks if there is water flow through the water sterilizer (10). If there is sufficient water flow, the MOSFET driver circuit (104) is switched on via a relay switching circuit (110) controlled by the microprocessor (102). The current consumption is then continuously measured in the current sensing circuit (106). If the current is below a predefined maximum of 2-4 Amperes, and the water continues to flow through the sterilizer (10), the MOSFET driver circuit is retained on. If the current exceeds a predefined maximum of 3-7 Amperes, or the water stops to flow through the sterilizer (10), the MOSFET driver circuit is switched off. A 12V direct current supply is connected to the connector (108). The voltage regulator (113) regulates the 5V voltage to the microprocessor.

The MOSFET driving circuit (104) generates a high frequency square wave that alternatively switches on the two MOSFET transistors (1 12.1 ) and (112.2). The two MOSFET transistors (112.1 ) and (112.2) are connected to two halves of a centre-tap, push-pull, step-up transformer (114). The switching frequency of the two MOSFET transistors (112.1 ) and (112.2) are 68KHz to 82KHz. The transformer (114) together with the inductor (116) and capacitor (118) defines an LC resonant circuit. The transformer (114) steps up the voltage from 12V to about 900V at its output.

The transformer (114) output is connected to a voltage multiplier (72) arranged in a Cockroft-Walton arrangement of diodes (74) and capacitors (76). The output (120) of the voltage multiplier 72 is connected to the sheath (16) of the water sterilizer (10) of Figure 1. In this embodiment, the sheath is of a conductive metal.

The output of the transformer (114) (before the voltage multiplier (72), is connected to the contacts of the UV lamp (14.2 and 14.2) and (14.3 and 14.4) respectively.

In operation, a high frequency switched voltage is provided on the UV lamp terminals via (122), and a direct current offset is provided over the UV lamp (14) terminals (14.2 and 14.2) and (14.3 and 14.4) and the sheath (16) by the voltage multiplier (72). The switching frequency of the MOSFET driving circuit (104) is tuned to resonate with the water sterilizer (10) setup.

In use, the gas in the UV lamp is ionized causing the gas to emit the UV light. The ionized gas plasma in use defines one terminal of a complex capacitor, while the combination of the glass tube of the UV lamp (14), the glass tube of the tubular water conduit (12) and the water in the water conduit (12) defines a di-electric medium of the capacitor and the metal sheath (16), connected to the connector (120) defines the other terminal of the capacitor. The inventor found that radiation of bacteria with normal Ultra Violet light does not provide the required sterilisation results.

However, the inventor found that the present arrangement of the water sterilizer (10) as depicted in Figure 1 connected to the high voltage circuit (100) shown in Figure 3 provides an improved arrangement to sterilize water.

The invention, as described, provides a new water sterilizer which enhances the oxidation process and effectively destroys all living contaminants, producing drinking water safe for human consumption. Moreover, the invention does not include any replaceable parts, minimizing the expense and effort required by the consumer.

Claims

CLAIMS:

1. A sterilizer, which includes

a conductive terminal spaced from the gas discharge lamp;

2. A sterilizer as claimed in claim 1 , in which the gas discharge lamp is a fluorescent lamp.

3. A sterilizer as claimed in claim 2, in which the fluorescent lamp is selected from any one of a low pressure lamp and a high pressure lamp.

4. A sterilizer as claimed in claim 1 , in which the conductive terminal is in the form of a sheath disposed at least partially around the gas discharge lamp.

5. A sterilizer as claimed in claim 5, in which the sheath defines at least a partial Faraday cage around the gas discharge lamp.

6. A sterilizer as claimed in claim 1 , in which the translucent fluid conduit defines a di-electric between the gas discharge lamp and the conductive terminal.

7. A sterilizer as claimed in claim 1 , in which

the translucent fluid conduit is a cylindrical fluid conduit, the gas discharge lamp is a low pressure tubular lamp disposed co-axially in the cylindrical fluid conduit, and

the conductive terminal is a metal sheath around the cylindrical conduit.

8. A sterilizer as claimed in claim 1 , in which the high voltage source comprises an alternatively pulsed MOSFET driving circuit connected to a centre-tap, push-pull, step-up transformer, the high voltage pulsed output of the high voltage source being the output of the step-up transformer.

9. A sterilizer as claimed in claim 8, in which the high voltage source further includes a voltage multiplier arranged in a Cockroft- Walton arrangement of diodes and capacitors, the high voltage direct current output of the high voltage source being the output of the voltage mulitplier.

10. A sterilizer as claimed in claim 9, in which the high voltage pulsed output and the high voltage direct current output of the high voltage source share a common terminal.

11. A sterilizer as claimed in claim 10, in which one terminal of the gas discharge lamp is connected to the common terminal.

12. A sterilizer as claimed in claim 8, in which the high voltage source includes a resonant circuit.

13. A sterilizer as claimed in claim 8, in which the resonant circuit is an LC resonant circuit at the input of the step-up transformer.

14. A sterilizer as claimed in claim 13, in which the step-up transformer, the gas discharge lamp, the conductive terminal and a fluid within the translucent fluid conduit forms part of the resonant circuit.

15. A sterilizer as claimed in claim 14, in which the resonant circuit includes capacitors at the high voltage pulsed output of the high voltage source.

16. A sterilizer as claimed in claim 15, in which the alternatively pulsed MOSFET driving circuit is frequency adjustable.

17. A sterilizer as claimed in claim 16, in which the alternatively pulsed MOSFET driving circuit is frequency adjustable between 68KHz and 82KHz.

18. A sterilizer as claimed in claim 8, in which the output voltage of the centre-tap, push-pull, step-up transformer is about 900V. 19. A sterilizer as claimed in claim 8, in which the output voltage of the voltage multiplier exceeds 10KV.

19. A sterilizer as claimed in claim 8, in which the in-circuit rise-time of the alternatively pulsed MOSFET driving circuit is less than 200ns.

20. A sterilizer as claimed in claim 1 , substantially as herein described and illustrated.

21. A new sterilizer, substantially as herein described.