Method and generator for generation of hydrogen peroxide

Abstract

A method and generator for generation of hydrogen peroxide which operate on the principle of conveying air-liquid or vapor flow through a corona discharge zone in air. Such devices can be used for disinfection of air and of various objects for industrial and home uses.

Claims

1. Device for generating hydrogen peroxide, the device comprising: a housing having inner walls containing an inlet for an air-liquid or a vapor and separate outlets for H.sub.2O.sub.2 and air outflow, first and second electrodes positioned within the housing so as to create a space within which the air-liquid or the vapor is able to flow, and a high AC voltage supply connected to the first and second electrode configured to generate between the electrodes a corona discharge having a straight segment; wherein: a hollow centrifugal fan rotor is mounted inside the housing and is operatively coupled to a motor for rotating about an axis; an open end of the hollow rotor faces the inlet so that incoming air-liquid or vapor flows into the hollow rotor; a corona discharge zone is formed between an inner wall of the rotor and an outer wall of the second electrode which is at least partially disposed within a cavity of the rotor; the air-liquid or vapor passing through the corona discharge zone is repelled radially by the rotor to the inner walls of the housing; and the rotor changes a direction of the air-liquid or vapor flow within the straight segment of the corona discharge.

2. The device according to claim 1, wherein at least part of the rotor is made from an electrically conducting material.

3. The device according to claim 1, wherein the high AC voltage supply is connected to the rotor via a capacitive coupling.

4. The device according to claim 1, wherein the second electrode is surrounded by an insulator and is disposed within a cavity of the centrifugal fan rotor.

5. The device according to claim 4, wherein an inner diameter of the rotor is displaced from an outer diameter of the insulator by a predetermined gap, a length of which is selected so as to derive a required corona discharge current at a preset magnitude of the high AC voltage supply.

6. The device according to claim 1, wherein the air outlet and the inlet are connected by a bypass channel.

7. The device according to claim 1, wherein the first electrode is an annular electrode rotatably attached to the rotor and is capacitively coupled to the high AC voltage supply via a static electrode fixed to the housing.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In order to understand the invention and to see how it may be carried out in practice, embodiments will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which:

(2) FIG. 1 is a schematic representation of a device for generating hydrogen peroxide according to the invention; and

(3) FIG. 2 is a partial cross-section through line A-A in FIG. 1.

DETAILED DESCRIPTION OF EMBODIMENTS

(4) Referring to FIG. 1 there is shown a device for generating hydrogen peroxide comprising a housing 1 toward an upper end of which there are mounted an electric motor 2 having power supply terminals 3 and an axis 4. An air capacitor is formed of an annular stator plate 5 which is supported toward the upper end of the housing and a rotor plate 6, (constituting a first electrode) which together with a hollow rotor 9 are attached to the motor axis 4. Also provided toward the upper end of the housing is an air outlet 7. An insulator 10 containing therein an electrode 11 constituting a second electrode is fixedly mounted inside the hollow rotor 9. A cold vapor inlet 12 and an H2O2 outlet 13 are formed in a lower part of the housing 1. The air outlet 7 is connected to the cold vapor inlet 12 via a bypass channel 8. A high voltage AC supply 14 fed by input terminals 15 has outputs connected to the stator plate 5 of the air capacitor (whereby it is capacitively coupled to the first electrode constituted by the rotor plate 6) and to the second electrode 11.

(5) The device operates as follows. As power is applied to the terminals 3 of the motor 2, the motor axis 4 rotates together with the rotor plate 6 of the air capacitor and the rotor 9, both of which are fastened to the motor axis 4. As power is applied to the terminals 15 of the high AC voltage supply 14, the stator plate 5 of the air capacitor and 25 the second electrode 11 are energized. In this way the high voltage AC is applied via the air capacitor to the rotor 9 and the second electrode 11 enclosed within the insulator 10.

(6) A barrier corona discharge zone shown as C in FIG. 2 is generated between the insulator 10 and the rotor 9 and is rotated together with the rotor 9 relative to the fixed insulator 10. At the same time, a low pressure zone created between the rotor 9 and the 30 insulator 10 sucks in the cold vapor from the vapor inlet 12 into the corona discharge zone C. The vapor that passes through the corona discharge zone turns to hydrogen peroxide (H.sub.2O.sub.2) and changes its initial flow direction in the zone by 90.

(7) Also referring to FIG. 2 it is seen that the corona discharge zone C is formed within the annular space between the inner diameter D1 of the rotor 9 and the outer diameter D2 of the insulator 10 surrounding the second electrode 11. The distance between D1 and D2 is determined from a consideration of the required corona discharge current produced at a preset magnitude of the high AC voltage.

(8) Since centrifugal force is generated during rotation of the rotor 9, large groups of liquid molecules composing the vapor are repelled to the cylindrical inner walls of the housing 1 forming drops of H.sub.2O.sub.2 which flow down along the inner walls and are removed from the device via the H.sub.2O.sub.2 outlet 13 in the lower part of the housing 1.

(9) As a result of the liquid separation process described above, air containing a certain amount of vaporous H.sub.2O.sub.2 and ozone O.sub.3 undissolved in the liquid remains in the device. Escape of air containing the above components from the device is undesirable. Therefore the air exiting the air outlet 7 is conveyed via the by-pass channel 8 to the cold vapor inlet 12 which allows for vapor injection into the device 10.

(10) By such means, recycled air circulates within in a closed space inside the device, thus obviating the need for an activated carbon filter and simplifying the design and maintenance of the device.

(11) A prototype of the device constructed using the proposed method has the following specification:

(12) TABLE-US-00001 Insulator material Glass Distance between the insulator of the first electrode and the 1 mm second electrode The rotor rotation velocity 6000 RPM The AC voltage source amplitude 7 kV The AC voltage source frequency 40 kHz Vapor consumption 300 mL/h H.sub.2O.sub.2 concentration at the generator outlet 100 ppm