WO2002059045A2

WO2002059045A2 - Device for water activation in an electric non-self-maintained glow discharge

Info

Publication number: WO2002059045A2
Application number: PCT/US2002/002074
Authority: WO
Inventors: Olexandr B. Zayika; Vasily P. Bakhar; Edward Levin
Original assignee: WATER WORKS GLOBAL, INC. a Corporation of Delaware, US
Priority date: 2001-01-25
Filing date: 2002-01-25
Publication date: 2002-08-01
Also published as: WO2002059045A3; AU2002240059A1

Abstract

A device is provided for activation of water in a medium of an electric non-self-maintained glow discharge. The device includes a reaction chamber, which comprises a case (30) that serves as an outer electrode, and a plurality of coaxially arranged inner electrodes (31). A clearance is provided between the inner and outer electrodes for initiation of the glow discharge. A power supply (14) is provided for applying a voltage which comprises an operating impulse voltage and an ionization impulse voltage to the electrodes. A cooling jacket (7) is placed on the outer side of the reaction chamber. Holes (35) are formed in the inner electrodes to allow for the flow of coolant. Injectors (33) are provided for feeding the water to be activated into the reaction chamber so that it flows along the inner surface of the case (30). A means for developing a vacuum inside the reaction chamber is proveded.

Description

DEVICE FOR WATER ACTIVATION, PRINCIPALLY OF CHEMICALLY PURE AND POTABLE IN A MEDIUM OF ELECTRIC NON-SELF-MAINTAINED GLOW DISCHARGE

Field of the Invention

The proposed invention relates to the domain of water activation, principally of potable and chemically pure, by increase of its reactivity's worth. The water, received by this method, can be used in medicine, veterinary medicine, agriculture, food, mining and processing, as well as in chemical industry. The invention can also be used for activation of any water-based mediums.

Background of the Invention

There are known devices for water treatment, based on the use of plasma of an electric discharge.

There is a known device for water activation, based on the use of an electrical corona discharge (JP, PN: 03181393, JP), which comprises a reaction chamber with two flat electrodes installed horizontally in a case thereof so as to face each other, and connected to a source of high voltage. The device is provided with a means for feeding treated water into the reaction chamber. The electric discharge plasma is produced between two said electrodes, when a high voltage of at least 3000 V is supplied.

There is a known device for water treatment, based on the use of electric filamentary discharges (DE 4440813) which comprises a reaction chamber, two electrically isolated from each other electrodes, one of which, that belongs to a gaseous atmosphere, is made as a plate, is provided with a dielectric and a cooling system, and is connected to a source of high voltage (8-12 kV) with a frequency of 200 kHz, and the other one, that is covered by fluid in the course of the process, is grounded and presents the case. The device is provided with a means for feeding a treated fluid into the reaction chamber.

However, this device also contemplates operation with high voltages, and that is unsafe.

The closest prior art of the invention is a device, intended for accomplishment of a method of water treatment (with the purpose of purification) by an electrical glow discharge, produced above a thin sheet of fluid at a constant voltage of 0.5-2 kV and an operating current strength of 50^100 mA under vacuum conditions, and while a specific temperature is maintained (RU, 2043969).

The said device (RU, 2043969) comprises a reaction chamber with at least two annular electrodes, arranged in the case thereof coaxially (in alignment), one of which is an internal electrode in relation to the other, external. There is a clearance provided between the said electrodes for flow of a treated fluid and for an electrical glow discharge, produced between the said electrodes, one of which covered with the treated fluid in the course of the device operation. The device also comprises a means for applying an electric potential to the said electrodes, which incorporates a source of an operating constant voltage, electrically connected with the said electrodes, a cooling jacket placed on the outer side of the said reaction chamber, a means for feeding the treated fluid into the said reaction chamber, and a means of vacuum development inside the said reaction chamber.

Is has been established that the basic operating factor, affecting the degree of water activation is the amount of applied energy per unit of a treated water per unit of the time of treatment. Therefore, to increase the process efficiency, it is necessary to increase the strength of the operating current of the glow discharge and to carry out the process of water activation with the help of the non-self-maintained glow discharge. However, no known device allows to use a current having a strength in excess of 0.1 A, since it causes a strong heat-up of electrodes, formation of an arc discharge and evaporation of the treated fluid.

It is an object of the invention to provide a device allowing to carry out water activation in a medium of a non-self-maintained glow discharge.

Another object of the invention is to provide conditions for the ionization and regulation of the operating discharge with the aid of ionization (excitant) discharge, applied to the same pairs of the unlike electrodes.

One more object of the invention is to provide opportunity to regulate value of strength of the operating impulse current, its clock frequency and duty cycle in the medium of operating discharge, as well as value of impulse current strength, clock frequency and impulse duration in the medium of additional ionization discharge.

Summary of the Invention

These objects are accomplished by the provision of a known device for activation of water, principally of chemically pure and potable, in a medium of an electrical glow discharge comprising a reaction chamber, at least two annular electrodes (internal and external) arranged coaxially with a clearance for initiation of the said glow discharge, a means for applying an electric potential to the said electrodes, which incorporates a source of an operating voltage, electrically connected with the said electrodes, a cooling jacket placed on the outer side of the said reaction chamber, a means for feeding the said water into the said reaction chamber, and a means of vacuum development inside the said reaction chamber, according to the invention, is provided with a cooling system of internal electrodes, whereas an external electrode presents a case of the said chamber, and the means for applying an electric potential to the said electrodes comprises sources of an operating impulse voltage and ionization impulse voltage, having a split-type connection with each of the said electrodes with the provision made for simultaneous supply thereto of the operating impulse voltage and ionization impulse voltage.

The internal electrodes therewith are made with through holes, increasing a cooling area, which are connected with the said cooling system of the internal electrodes.

The internal electrodes cooling system is made as a tube, passing through the said electrodes, or as two, arranged in alignment tubes, passing through the said electrodes.

The clearance between the internal and external electrodes is 4-20 mm.

It is preferred, that there are at least two internal electrodes, electrically isolated from each other.

The number of the internal electrodes is determined by the volume of water, subject to activation per unit of time.

The provision is further made for magnets, installed on the outside of the said reaction chamber opposite the internal electrodes, with the provision for the removal thereof in the discharge zone.

The magnets therewith are made of an annular shape.

The said reaction chamber is made of a cylindrical shape, for example, with the inside diameter of 25-250 mm and the height of 150-1500 mm, and is installed upright.

The said means for water delivery into the said reaction chamber is made with a provision for feeding the said medium onto the internal surface of the external electrode in a turbulent flow, for example, as injectors having a tangential arrangement along a circle at an angle preferably of 5-30°, relative to the horizontal plane of the reactor.

The said sources of an operating impulse voltage and ionization impulse voltage have a split-type connection with each of the said electrodes, with the provision made for simultaneous supply thereto of the operating impulse voltage and ionization impulse voltage.

The internal electrodes are made of a metal, having a thermal conductivity factor of at least 100 W/(mK).

The outside surface of the internal electrodes is made of a refractory metal, for example, tungsten or nickel-chromium alloy.

The magnets are made so that to provide a magnetic field with a value of magnetic induction of at least 0.01 T (Tesla). Brief Description of the Drawings

The essence of the invention will now be illustrated by graphics, where Fig. 1 is a block diagram of the device for water activation;

Fig. 2 is a longitudinal sectional view of a reaction chamber, where proper water activation occurs;

Fig. 3 is a cross-sectional view of the said reaction chamber taken along line A^aA.

Detailed Description of the Invention

A device for water activation (Fig. 1) comprises a reaction chamber 1 (hereinafter referred to as the "reactor 1 ") where a non-self-maintained glow discharge is produced and proper water activation occurs, a reservoir 2 for accumulation of water, before it is fed to the reactor 1 provided with a float valve 3, a means 4 providing for vacuum development in the reactor 1, a unit 5 for monitoring selected vacuum parameters in the reactor 1, a unit 6 for feeding water from the reservoir 2 into the reactor 1, units 7 and 8 for cooling the reactor 1, a reservoir 9 for collection of activated water, a pump 10 for pumping out the activated water from the reservoir 9, a filter 11 con^ nected with the pump 10, a three-way valve 12 installed at the outlet of the filter 11, a pipeline 13 connecting the reservoir 2 with the valve 12, an electrical power supply source 14 for energizing the reactor 1 and a means 15 providing control over and monitoring of operation of the entire device.

The means 15 can be made, for example, as a processor.

A device as claimed in the invention, can be made with one reactor 1 or more.

The means 4 providing for vacuum development in the reactor 1 comprises a water-jet ejector 16, a pump 17 provided for operation of the ejector 16, a reservoir 18 for water provided for operation of the ejector 16 with a float valve 19 and a pipeline 20 connecting the pump 17 with the ejector 16.

The unit 5 for monitoring the selected vacuum parameters in the reactor 1 comprises a pressure transmitter 21 connected with the reactor 1 and a controller 22 of the pressure transmitter 21, and a solenoid^operated valve 23.

A pipeline 24 connects the ejector 16 to the reactor 1 and the reservoir 9 for vacuum development therein.

The unit 6 for feeding fluid from the reservoir 2 into the reactor 1 comprises a coarse filter 25, a solenoid-operated valve 26 and a pipeline 27 connecting the reservoir 2 with the reactor 1. The unit 7 for cooling the reactor 1 is essentially a jacket, placed around the reactor 1, connected with the means (not specified on the drawing) for pumping a liquid coolant through the jacket.

The unit 8 for cooling the reactor 1 comprises a heat exchanger 28, an oil pump 29 and means for cooling oil heat exchanger 28.

The means for cooling oil in the cooler 28 can be provided in form of a cooled water.

The pumps 10 and 17, the electric power supply source 14, the controller 22 of the pressure transmitter 21, and the solenoid-operated valve 23, the solenoid-operated valve 26, the oil pump

29 are connected with the control means 15 (the connection is not specified on the drawing).

The reactor 1 (Fig. 2) is made as a chamber and comprises a case 30 being an electrode that is covered during the operation with the treated fluid. There are electrodes 31 installed in the case

30 of the reciprocal, relative to the electrode 30, potential, whieh are in a gaseous atmosphere during operation of the reactor 1, and a system 32 for cooling the electrodes 31. The reactor 1 is equipped with the means for delivering and forming a stream of the treated fluid made, for example, as injectors 33. Magnets 34 are installed on the outer side of the case 30 opposite the electrodes 31 with the provision for the removal thereof.

The electrodes 31 (Fig. 3) are made of annular shape, with through holes 35 connected with the cooling system 32 made as two coaxial pipes, connected with the unit 8 (Fig. 1) for cooling the reactor 1 by the feed and lateral pipelines (not specified on the drawing).

The magnets 34 are the permanent magnets (it is also practicable to use electromagnets), made of annular shape and installed with the provision for the removal thereof near the unlike electrodes.

The jet injectors 33 have mainly a tangential arrangement at equal distance along a circle at an angle of 5-30° (at an angle of 15° in this device) relative to the horizontal plane of the reactor 1 , and are connected by the pipeline 27 to the reservoir 2.

The case 30 being an electrode and the electrodes 31 are electrically connected to the electric power supply source 14.

The electric power supply source 14 comprises sources of the operating impulse voltage and ionization impulse voltage each being individually connected to the electrodes 30 and 31.

The case- 30, being an electrode, of the reactor 1 is made-m-a form of a hollow cylinder (tube) with the inside diameter of 25-250 mm and the height of 150-1500 mm. The case 30 is made of a material, having no catalytic effect on the treated water, namely of titanium, and is installed spatially upright. The use can be also made of vanadium, zirconium, tin, tantalum. In a par- ticular embodiment, the reactor 1 is made with the inside diameter of 80 mm and the height of 900 mm..

The electrode 31 can comprise one or more electrode members. To activate large volumes of water, it is necessary to have a large surface area of the active electrode. Therefore, the elec- trode 31 can be a cluster electrode. The number of the members thereof is determined by the time, required for the treated fluid to stay in the reaction zone in order the selected degree of activation can be achieved.

In a particular embodiment of the invention the electrode 31 consists of 6 members.

A separate conductor 36 connects every electrode 31 to the power supply source 14. There is a galvanic isolation between the electrodes 31 and the case 30 (being an electrode) of the reactor 1 and between the electrodes proper provided by dielectric hollow inserts 37 made of ceramics.

In a particular embodiment of the invention, the electrodes 31 are installed so that they have a clearance of 8 mm relative to the electrode 30.

The electrodes 31 are made of a metal, having a thermal conductivity of at least 209 W/(mK) (in a particular embodiment of the invention is of aluminum). The outside surface of the electrodes 31 is covered with a refractory metal, for example, tungsten or nickel-chromium alloy.

The magnets 34 are made, so that to provide a magnetic field with a value of magnetic induction of at least 0.01 T in the zone of the discharge.

The device according to the invention functions in the following manner:

In response to control signals of the control means 15 (a processor ), a reduced atmospheric pressure from 30 up to 250 Torr (from 4_*10³ to 3.3*10⁴ Pa), i.e. vacuum, is developed in the case 30 of the reactor 1 with the aid of the water-jet ejector 16. In this case_s water to the ejector 16 is fed from the reservoir 18 with the use of the pump 17. The selected vacuum parameters are monitored with the aid of the pressure transmitter 21, the controller 22 of the pressure transmitter 21 and the solenoid-operated valve 23. In so doing, the controller 22 of the pressure transmitter 21 digitizes data received from the pressure transmitter 21 and feeds this information to the processor 15.

Simultaneously, the liquid coolant is pumped through the unit 7, i.e. the cooling jacket of the reactor 1, and the cooling transformer oil is pumped through the unit 8 connected with the cooling system 32, thus ensuring maintenance of the selected temperature in the reactor 1 below the natural boiling point of the treated water. After the selected vacuum value has been attained, the solenoid-operated valve 26 opens in response to a control signal of the processor 15, and water is fed for treatment in a turbulent flow 0.3-5 mm in depth from the inlet reservoir 2 through the pipeline 27 and the injectors 33 into the reactor 1. The filter 25 therewith allows to prevent suspension particles in the treated water from getting on the injectors 33. After that, the operating impulse voltage of no more than 500 V with the clock frequency of 0.1-100 kHz, and the ionization impulse voltage featuring the value of 2- 10 kV, the current strength of 30-5000 μA and the pulse duration of (K01-20 μs, are simultaneously applied to the electrodes 30 and 31, thus producing a non-self-maintained glow discharge with an adjustable operating current of 0.1-20 A on each pair of the unlike electrodes, the voltage of no more than 500 V, the clock frequency of 0.1-100 kHz and the duty cycle of at least 1.3.

Such conditions of producing the non-self-maintained glow-dtseharge, allow to implement the process at an average in time value of impulse current strength of up to 20 A and a voltage of no more than 500 V with the provision for adjustment of the eteek frequency and duty cycle of the current.

The water is treated in the medium (plasma) of the non-self-maintained glow discharge in presence or in absence of a magnetic field.

The water, treated in the medium of the non-self-maintained glow discharge, drains into the reservoir 9, wherefrom it is delivered to the filter 11 by the pump 10 for extraction of insoluble sludge, that coagulates during the water activation.

If it is necessary to obtain high activity parameters of a treated water, such water is subject to a multiple treatment in a cyclic duty, for which purpose the activated water is returned through the valve 12, the pipeline 13 into the receiving reservoir 2, and is delivered again into the reactor 1 through the pipeline 27.

The invention is further illustrated by the following embodiments of water activation process with the use of the device, according to the invention:

Embodiment 1. Subject to treatment was distilled water having pH=6.6, twice-distilled water having pH=6.15 and potable water having pH=7.7.

A degree of activation of distilled, twice-distilled and potable water was examined in relation to the average in time value of strength of the impulse operating current. Water was subject to treatment in the medium (plasma) of a non-self-maintained glow discharge, produced with the aid of the above-described device, and such treatment consisted in passing thereof in a turbulent flow 0.5mm in depth through the zone of the discharge in cyclic mode . To produce the discharge, the operating impulse voltage of 490V with the clock frequency of 2 kHz was applied to the electrodes 30 and 31. Simultaneously, the non-self-maintained glow discharge plasma was produced with the aid of ionization impulse voltage of 10 kV with the strength of impulse current of 5mA with the pulse duration of 1 Oμs, and clock frequency 40 kHz, which was also applied to the electrodes 30 and 31.

Water was treated by the non-self-maintained glow discharge, having the. value of impulse operating current strength 1 A, 2.5 A, 5 A, 7.5 A, 10 A and 12.5 A on four pairs of the unlike electrodes and the relative pulse duration of 2.

The distance from the water surface to the electrodes in gaseous atmosphere was 8 mm. The pressure in the reactor was maintained at the level of 50Torr, the inlet fluid temperature at the reactor was T=293 K.

Simultaneously, the non-self-maintained glow discharge plasma was further affected by a magnetic field with the value of magnetic induction being 0.02 T in the discharge zone.

The treatment results are presented in Table 1.

Table 1

As can be seen from Table 1, with increase of the strength of the operating impulse current, the concentration of hydrogen peroxide and super-oxide compounds increases, thus raising the degree of activation of aqueous mediums. Embodiment 2

Subject to treatment was distilled water having pH=6.5.

A degree of activation of distilled water was examined in relation to the average in time value of the operating impulse current strength, and the relative pulse duration of the non-self-maintained glow discharge.

Water was subject to treatment in the medium (plasma) of a non-self-maintained glow discharge, produced with the aid of the above-described device, and such treatment consisted in passing thereof in a turbulent flow 0.55 mm in depth through the zone of the discharge. The operating impulse voltage of 480V with the clock frequency of 1500Hz was applied to the electrodes 30and 31.

The non-self-maintained glow discharge plasma was produced with the aid of ionization impulse voltage of lOkV, with the impulse strength current of 3mA, with the pulse duration of 15μs and clock frequency of 40 kHz, which was also applied to the electrodes 30 and 31. Water was treated in the medium of the non-self-maintained glow discharge, having the impulse operating current of 1 A A and 10 A and the relative pulse duration of 2, 3, and 4. The pressure in the reactor was maintained at the level of 50Torr, the inlet fluid temperature at the reactor was T=293 K_;

Simultaneously, the non-self-maintained glow discharge plasma was further affected by a magnetic field with the value of magnetic induction being 0.02 T.

The treatment results are presented in Table 2.

Table 2.

The analysis of data presented in Table 2 shows, that the maximum degree of water activation (concentration of hydrogen peroxide and super-oxide compounds) was obtained at the relative pulse duration of 2, and the average in time value of strength of the operating impulse current of 10 A. Application of the operating current with the relative pulse duration more than 2, decreases the degree of activation.

Embodiment 3. Potable water with initial value pH=7.8 was subject to treatment by a non-self-maintained glow discharge, by passing thereof in a turbulent flow 0.55mm in depth through the zone of the discharge in cyclic .

A degree of activation of potable water was examined in relation to the value of the impulse operating current and frequency.

The treatment was carried out by plasma of a non-self-maintained glow discharge, produced with the aid of the above-described device.

The operating impulse voltage of 470 V with the clock frequency of 100 Hz and 400 Hz was applied to the electrodes 30 and 31.

The non-self-maintained glow discharge plasma was produced with the aid of ionization impulse voltage of 10 kV, with the impulse current strength of 4mA, with the pulse duration of 5 μs and clock frequency 20 kHz.

The distance from the water surface to the electrodes in gaseous atmosphere was 12mm. Water was treated by the non-self-maintained glow discharge, having the average in time value of strength of the impulse operating current of 2 A 6A, and 10A on two pairs of the unlike electrodes, and the relative pulse duration of 2.

The pressure in the reactor was maintained at the level of 50Torr, the inlet fluid temperature at the reactor was 1 T=293 K.

The results of potable water activation are presented in Table 3.

Table 3.

The analysis of data, presented in Table 3, proves that the degree of wafer activation depends on the average in time value of the operating impulse current strength and clock frequency. Thus, the degree of water activation increases with the increase of the average in time value of strength of the operating impulse current and clock frequency.

Thus, the device according to the invention allows to carry out water activation in the medium of a non-self-maintained glow discharge and to provide for adjustment of the value, clock frequency and relative pulse duration of the impulse operating current thereby allowing to select the most optimal conditions of water activation and to achieve required indicators of the pH-value and concentration of hydrogen peroxide and super-oxide compounds.

Claims

1. A device for water activation, principally of chemically pure and potable, in a medium of a glow discharge comprising a reaction chamber, at least two annular electrodes (internal and external) arranged coaxially with a clearance for initiation of said glow discharge, a means for applying an electric potential to said electrodes which incorporates a source of an operating voltage electrically connected with said eteetrodes, a cooling jacket placed on the outer side of said reaction chamber, a means for feeding said water into said reaction chamber, and a means of vacuum development inside said reaction chamber, wherein, said device is provided with a cooling system of internal electrodes, whereas an external electrode presents a case of said chamber, and the means for applying an electric potential to said electrodes comprises sources of an operating impulse voltage and ionization impulse voltage, having a split-type connection with each of said electrodes with the provision made for simultaneous supply thereto of the operating impulse voltage and ionization impulse voltage.

2. A device as claimed in claim 1, wherein the internal electrodes are made with through holes increasing a cooling area, which are connected with said cooling system of the internal electrodes.

3. A device as claimed in claim 1, wherein the internal electrodes cooling system is made as a tube, passing through said electrodes.

4. A device as claimed in claim 1, wherein the internal electrodes cooling system is made as two, arranged in alignment, tubes, passing through said electrodes.

5. A device as claimed in claim 1, wherein the clearance between the internal and external electrodes is 4-20 mm.

6. A device as claimed in claim 1, wherein it comprises at least two internal electrodes electrically isolated from each other.

7. A device as claimed in any of the foregoing claims 1 through 6, wherein it is equipped with magnets installed on the outside of said reaction chamber opposite the internal electrodes with the provision for the removal thereof in the discharge zone.

8. A device as claimed in claim 7, wherein the magnets are made of an annular shape.

9. A device as claimed in claim 1 , wherein said reaction chamber is made of a cylindrical shape.

10. A device as claimed in claim 9, wherein said reaction chamber is installed upright.

11. A device as claimed in claim 1, wherein said means for water delivery into said reaction chamber is made with a provision for feeding said medium onto the internal surface of the external electrode in a turbulent flow.

12. A device as claimed in claim 11, wherein said means for water delivery in a turbulent flow is made as injectors having a tangential arrangement along a circle at an angle to the direct axis of the reaction chamber.

13. A device as claimed in claim 6, wherein said sources of an operating impulse voltage and ionization impulse voltage have a split-type connection with each of said electrodes with the provision made for simultaneous supply thereto of the operating impulse voltage and ionization impulse voltage.

14. A device as claimed in claim 9, wherein said reaction chamber is made with the inside diameter of 25-250 mm and the height of 150-1500 mm.

15. A device as claimed in claim 12, wherein the injectors are arranged at an angle of 5-30° relative to the horizontal plane of the reactor.

16. A device as claimed in claim 1, wherein the internal electrodes are made of a metal, having a thermal conductivity factor of at least 100 W/(mK).

17. A device as claimed in claim 1, wherein the outside surface of the internal electrodes is made of a refractory metal, for example, tungsten or nickel-chromium alloy.

18. A device as claimed in claim 6, wherein the magnets are made so that to provide a magnetic field with a value of magnetic induction of at least 0.01 T.

19. A device for water activation, principally of chemically pure and potable, in a medium of a glow discharge, comprising a reaction chamber, at least two annular electrodes (internal and external) arranged coaxially with a clearance for initiation of said glow discharge, a means for applying an electric potential to said electrodes, which incorporates a source of an operating impulse voltage electrically connected with said electrodes, a cooling jacket placed on the outer side of said reaction chamber, a means for feeding said water into said reaction chamber, and a means of vacuum development inside said reaction chamber, wherein, said device is provided with a cooling system of internal electrodes, whereas an external electrode presents a case of said chamber, and the means for applying an electric potential to said electrodes comprises sources of an operating impulse voltage and ionization impulse voltage having a split- type connection with each of said electrodes with the provision made for simultaneous supply thereto of the operating impulse voltage and ionization impulse voltage, said reaction chamber therewith is made of a cylindrical shape with the inside diameter of 25-250 mm and the height of 150-1500 mm and is installed upright, the internal, at least two, electrodes are made of a metal having a thermal conductivity factor of at least 100 W/(mK), the outside surface of a refractory metal, for example, tungsten or nickel-chromium alloy , with through holes in- creasing a cooling area, which are connected with said cooling system of the internal electrodes, made, for example, as a tube passing through said electrodes, and are electrically isolated from each other, the clearance between the internal and external electrodes is 4=20 mm, and the means for said water delivery is made as injectors having a tangential arrangement along a circle at an angle of 5-30° relative to the horizontal plane of the reactor.

20. A device as claimed in claim 19, wherein it is equipped with magnets of an annular shape, providing a magnetic field with a value of magnetic induction of at least 0.01 T and installed on the outside of said reaction chamber, opposite the internal electrodes with the provision for the removal thereof.