Patent Application
20160175803
This invention relates to methods and devices for the generation of hydrogen peroxide operating on the principle of conveying air-liquid or vapor flow through a corona discharge zone in air.
CN 1011569515 discloses a non-equilibrated plasma type spray sterilization disinfectant generating device, consisting of a main unit and a plasma spray head. A high voltage potential difference between metal electrodes in the plasma spray head is utilized to form a corona discharge where the distance between the metal electrodes is minimal. The corona discharge is driven by an air-water mixture generated by an atomization nozzle, so as to quickly slide downstream along an electrode surface and form a pulse type sliding arc discharging non-equilibrated plasma on the electrode surface. An air-water mixture containing hydrogen peroxide, ozone, oxyhydrogen free radical, oxygen free radical, and other oxidizable particles is produced and sprayed from the insulator casing to form air-water spray sterilization disinfectant.
It is also known to produce the air-liquid spray using an air compressor which conveys air at a high speed (50-100 m/sec) through a corona discharge zone.
The flow conveyed through the corona discharge zone contains hydrogen peroxide (H2O2) and ozone (O3) which are delivered to the object being disinfected. A drawback of such a method is that part of the ozone is dissolved in the liquid, while the remainder is present in the airflow.
Also known is an approach in which the air-liquid spray is again produced by means of an air compressor and conveyed through a corona discharge zone, but is thereafter separated into liquid hydrogen peroxide and air which contains undissolved ozone in the liquid.
In order to remove the ozone, the air may be conveyed through an activated carbon filter.
A common disadvantage of the previous state of the art is its limited field of application which stems from the need for an air compressor.
An object of the present invention is therefore to provide a method and device for generating hydrogen peroxide which address disadvantages of the prior art.
This object is in the first place achieved by generating cold vapor, which is used as an air-liquid flow, using the well-known method of ultrasonic generation in water, thus avoiding use of the costly compressor.
Unlike the air-liquid flow generation by means of an air compressor which is related to jet technologies, cold vapor generation can be related to “cloud technologies”, since the cloud vapor is generated under normal pressure when the vapor “cloud” remains immobile unless an external source is used to generate a pressure fall. A fan is generally used as such a source.
The proposed method is based on the use of a hollow rotor which performs three functions simultaneously.
The rotor or at least a part of it is made of a conducting material.
The other electrode which is coated with insulation is mounded inside the rotor cavity.
Power from a high voltage AC source is applied to the rotor from one of the terminals via capacitive coupling while the second terminal is directly connected to the second electrode. In this way a straight segment of corona discharge is generated between the rotor and the second electrode insulator.
The distance between the inner diameter of the rotor and the outer diameter of the second electrode insulator is determined from a consideration of the required corona discharge current produced at a preset magnitude of the high AC voltage.
The rotor shaped as a centrifugal fan rotor is rotated around the second electrode. The corona discharge zone is rotated too.
As mentioned before the cold vapor is drawn into and rotates within the corona discharge zone.
The rotational velocity of the rotor and the corona discharge zone is much higher than that of the cold vapor because of the strong impact of the corona discharge on the vapor. It is subjected to a strong influence of the corona discharge.
Vapor separation to liquid and air using centrifugal force produced by the rotor is attained by changing by 90° the direction of the cold vapor transmission through the straight segment of corona discharge between the electrodes. The above angle may change slightly depending on the electrodes configuration.
One of the advantages of the proposed method of H2O2 generation is the increase of the H2O2 concentration when hydrogen peroxide produced at the generator outlet in a liquid form is used to generate the vapor entering the generator. To do this the generator outlet is connected to a reservoir of liquid that is intended to be converted into vapor.
Actually the concentration is increased due to the proportional increase of the generator operation time.
A device according to the invention for generating hydrogen peroxide (H2O2) comprises:
A cylindrical body with a cold vapor inlet and an air and H2O2 outlets from the body, a bypass air channel, stator and rotor plates of air capacitor, a motor with a rotor plate of the air capacitor fastened to its axis and a rotor which together with the motor and the body form a centrifugal fan, an insulator with an electrode mounted inside the rotor cavity and a high AC voltage supply.
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:
Referring to
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.
A barrier corona discharge zone shown as C in
Also referring to
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 H2O2 which flow down along the inner walls and are removed from the device via the H2O2 outlet 13 in the lower part of the housing 1.
As a result of the liquid separation process described above, air containing a certain amount of vaporous H2O2 and ozone O3 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.
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.
A prototype of the device constructed using the proposed method has the following specification:
