Device for cleaning of gases from dust particles with or without ionisation Wn lfh dry, wet or both dry and wet catching.

Preface Electro-filters and cyclones are often used for cleaning of dust from gases. In electro-filters the particles must be ionised before they can be collected in some type of collector. According to known technology the ionisation is done by charging a sender electrode with high voltage and connecting a receiving electrode to another polarity and placing it in the neighbourhood of the sending electrode. Between these two electrodes a so-called Corona effect occurs which ionises the particles.

For being able to manage the ionisation the distance between the sending electrodes and receiving electrodes must be shorter than a certain limit value, which among others is depending on the voltage of the sending electrode and the composition of the gas. By using a part of this innovation the ionisation can be made in any channel wideness.

After the particles are ionised they are collected in some type of collector. It has been shown that wet collectors often give the best cleaning. But one problem is that if the particle concentration is high the water will be so dirty that it is difficult to clean the water properly.

Consequently sludge in the water creates problems. This innovation gives an opportunity to collect part of the particles in dry form, which reduces the problems with the sludge. The main part of the remaining particles is then collected in the water.

Components list On this list of the components the name of all the components is given. Only a smaller part of the names of the components are used in the following descriptions. To get the names of the other components, see this list.

Central electrode rod 01, isolator ring 02, gas inlet with a rotation device 04, outer casing 05, drop collector 06, water distributor 07, collector/condenser 08, water magazine 09, water distributor 10, collector 11, dust outlet 13, scaling ring 14, water magazine 15, water pipe 16, pump 17, receiving electrode 18, receiving electrode 19, receiving electrode 20, pump 21, heat exchanger 22, receiving electrode 23, water pipe 24, gas outlet 25, channel 26, electrode ring 27, water inlet 28, support 29, electrode carrier 30, electrode tip 31, protecting pipe 32, electrode 33, hole 34"guiding plate 35, roof 36, outer casing 37, guiding ring 38, pipe 39, dust layer 40, dust connection 41, guiding plate 42, hole 43, guiding casing 44, pipe 45, dust connection 46, bottom 47, dust layer 48, outer casing 49, roof 50, gas channel 61, gas with dust content 62, cleaned gas 63, central pipe 64, inlet 65, outlet 66, isolator ring 67, gas inlet with a rotation device 68, electrode 69, inlet 70, dust outlet 71, cone 72, outer wall 73, roof 74, outer casing 75, guiding casing 76, gas outlet 77, roof 78, receiving electrode 79, support 80, electrode ring 81, support 82, stack 101, drop collector 102, water distributor 103, collector/condenser 104, water magazine 105, water distributor 106, collector 107, water magazine 108, gas inlet 109, outer casing 110, dust collector 111, support leg 112, fundament 113, feeding out valve 114, cyclone element 115, diffuser plate 116, hat 117, pump 118, water pipe 119, pump 120, heat exchanger 121, return water pipe 122, water pipe 123, outer casing 124, outer casing 125, dust collector 126, hat 127, gas channel 128, receiving electrode 129, receiving electrode 130, electrode ring 131, support 132, electrode ring 133, gas inlet 134, gas chamber 135, support 136, support 137, electrode rod 138, receiving electrode 139, support 140, support 141, support 142, outer casing 143, guiding mantle 144, gas channel 145, roof 146, water magazine 147, electrode ring 148, support 149, gas channel 150, outer casing 151, push electrode 152, electrode 153, electrode 154, receiving electrode 155, electrode 156, gas channel 157, system for ionisation 158, supporting ring 159, frame 160, fundament 161, push electrode 162, outer casing 163, cone 164, dust collector 165, feeding out valve 166, feeding out valve 167, separating wall 168, dust collector 169, dust channel 170, push electrode 171, central pipe 172, gas inlet 173, support 174, receiving electrode 175, electrode ring 176, support 177, adapter to isolator 179, push electrode 180, channel 181, roof 182, guiding mantel 183, outer mantel 184, adapter 185, outer casing 186, bottom 187, gas ring 188, diffuser 189, outer guiding 190, throttle ring 191, rotation bearing 192, ionisation 193, isolator 194, push electrode 195, central electrode 196, separating mantle 197, dust pipe 198, pipe opening 199, outer casing 200, cone 201, feeding out valve 202, central pipe 203, guiding plate 204, scaling ring 205, scaling ring 206, gas channel 207, push electrode 208, electrode wire 209, electrode ring 210, tip electrode 211, electrode ring 212.

All the electrodes and the push electrodes are isolated from the rest of the equipment even if it is said in the following text.

Function description The function of one part of the innovation is shown in the Fig. 1 for a system where the surface of the first collector is dry and the surfaces of the two additional collectors are wet. In the Fig. 4 a totally dry system is shown. Figures 2 and 3 show details for this type of ionisation. Figures 5-32 show alternative solutions.

Devise according to the Fig. 1.

A cyclone function is included in this design why the gas as put in rotation before it enters a circular heat insulated channel (26). In the Fig. 1. an alternative way is shown how the rotation is created. The gas is entering through a gas inlet (04) that is tangentially connected to a circular outer casing (05). It is also possible to create the rotation through guiding vanes at the inlet to the circular channel (26). The channel (26) is divided in two or more circular part channels with cylindrical mantles, receiving electrodes (18), (19), (20) and (23) in the example according to the Fig. 1. The mantles are connected in to the mantle (26) with radial rods. All the mantles are earthed. The mantles are working as receiving electrodes for a number of sending electrodes, which are carried by a central electrode carrier (01). An isolator (02) is separating the sender electrode from the roof of the devise.

An example of a suitable sending electrode is the following: The sending electrode consists of a central rod (01) on which a number of electrode rings (27) are attached according to the Fig.

2. In the rings (27) there are according to the Figure 3. protecting pipes (32) inside which the sending electrodes (33) are located. The sending electrodes (33) have a tip (31) which is inside the protecting pipe for protecting it from dirt. The corona effect occurs between the tip and the mantle that is located outside the actual electrode. In the example according to Fig. 1. there are five electrode rings located inside every mantle. As an alternative it is possible to build together the rings inside one mantle to a single broad electrode ring. The rings are located so that the electrodes are not on the same vertical line. The gap between the tips (31) and the mantle is selected so narrow that the Corona effect certainly occurs at the voltage used. In the device according to the Figure 1 five gaps are used for the ionisation. The outer casing (26) is used as the receiving electrode. The sending electrodes for the lowest gap are placed inside the central rod (01).

To use protected electrodes with a tip is only one alternative to concentrate the Corona effect on the tip. Other types of electrodes, for example plain rings or rings with notches can also be used in the device.

In all the circular mantles there is a tangentially placed nozzle (28) according to the Fig. 2. If the device is working with wet collectors it its possible to continuously inject water through the nozzle (28) and the water forms then a water film on the inside wall of the mantle. This film works as a collector and cleans the surface of the wall. In this case water is injected already before, at or after the inlet (04) to form a water film on the inner surface of the circular channel (26). By injecting water early enough before the inlet (04) it is also possible to decrease the gas temperature before the ionisation that results in a lower pressure loss, lower gas speed and increases the ionisation.

If the goal is to collect part of the dust in dry form the water is injected only intermittent through the nozzles (28) and on the inner surface of the outer casing (26) ~ for cleaning the inner surfaces of the mantles. During the main part of the time the ionisation is then working in dry form. If there is no need of cleaning or if the cleaning is done on a conventional way, for example by hammering or by ultra sound no water is injected and this part of the device is working completely dry. Compressed air can as an alternative be used for the cleaning through the nozzles (28). Several nozzles are then needed in every ring.

When running the device dry a gas layer with increased dust content is build nearest the inner wall of the mantle (26). A scaling ring (14) with a smaller diameter than the inner diameter of the outer casing is placed near the lower end of the mantle (26) so that there is a gap, which lets that gas flow through which contains an increased content of dust. This flow is directed through a dust outlet (13) to a conventional cleaner, for example a cyclone or filter, from which the cleaned gas is directed back to the main flow for example through a channel inside the scaling ring (14). In that case the velocity of the gas is carefully decreased so that the static pressure of the gas that is returned inside the ring (14) increases to a higher level than the pressure inside the ring (14). This fact is valid for all the alternative solutions for cyclones in this innovation.

The partly cleaned gas flows through the scaling ring (14) against a water surface (15) that additionally collects part of the particles. After that the gas turns into the up going direction and flows through a bed (11) of filling pieces. Water is poured according a known technology on the filling pieces from a water distributor (10) that gets its water from a water magazine (15) through a pump (17) and a pipe (16). After that part of the condensation heat is recovered in a condenser (08) with its water system inclusive a heat exchanger (22) into the plants return water system. This cleaning system is in more detail described in the patent application 9803695-7, especially in the Fig. 4. After that the cooled and cleaned gas goes through a drop collector (06) out through an outlet (25) into the surrounding air or into a stack. A certain after heating can be arranged by letting be to heat insulate that part of the mantle (26) that is on the upside of the water distributor (07). If still higher after heating is needed an after heater is build in the outlet (25) or warm gas is blended in the gas.

Device according to the Fig. 4.

In this alternative the ionisation is done as in the Fig. l., but the device is run only dry with exception of eventual short cleaning periods when water is injected through the nozzles (28) and through the nozzles which inject water on the inner wall of the outer casing (26). The device is shown in the Fig. 4. with a vertical flow direction, but the direction can be at any chosen angle from the vertical line. The dust outlet (13) is depending of the angle placed so that the dust can be taken out downwards.

The outer mantle (26) is lengthened so that the dust particles get a longer time to travel to the inner wall of the mantle (26). The cleaned gas in the centre of he mantle is taken out through a pipe that is an extension of the scaling ring (14). The gas with a high dust content near the inner wall of the mantle (26) is directed through the gap between (26) and (14) out through the dust outlet (13) where it is taken care on the same way as in the Fig. 1.

Device according to the Fig. 5.

In this alternative the-ionisation is done as-in the Fig. 4. A cyclone is build into the outlet for being able to collect the dust there why no extra cleaner is needed.

The cleaned gas in the centre of the mantle (26) is directed out through the pipe (39). The gas with extra high dust content near the inner wall of the mantle (26) is directed to a channel between the roof (36) of the outer casing (37) and a guiding plate (35). A certain form is shown in the Fig. 5, but (35) and (36) can also be horizontal and (37) cylindrical. The gas flow with dust particles is rotating in a downward direction and part of he dust particles are thrown against the outer wall (37) and fall then down into the dust layer (40). A connection (41) is connected to a feeding out valve for emptying the dust layer between certain intervals.

The cross sections between (38) and (37) and (38) and (39) have such dimensions that the gas velocity goes down and the static pressure of the gas increases when the gas flows into the space around the pipe (39). The gas near the centre of this space is cleaner and returns into the system through the gap between the pipe (39) and the guiding ring (38) and further into the inside of the pipe (39) through the pipes (34) because the static pressure is lower inside the pipe than in the gap between (38) and (39). The fact that the velocity of the gas is decreased is valid for all the alternative solutions for cyclones in this innovation.

If the ionisation results in unwanted dust layers it is possible to clean them by cutting of the high voltage during a short period. The gas velocities in the system are so high that the surfaces will be blown clean when the high voltage disappears. This comment is valid for all shown devises with ionisation.

Device according to the Fig. 6.

This device is like the device according to the Fig. 1. in other ways but a cyclone similar to the cyclone in Fig. 5. is build in the outlet of the channel (26). The cleaned flow with dust is directed by the guiding mantle (44) to a hole through the pipe (45) and into the pipe (45). The cross sections outside (45) are so large that the velocity of the gas decreases why the static pressure before the hole in the pipe (45) is higher than inside the pipe (45 and the cleaned gas can flow into the inside of the pipe (45). The cleaned main flow comes out through the pipe (45) in the direction to the water magazine (15) and turns then upwards and flows through the gap between the outer casing (05) and the outer wall of the cyclone (49) into the space over the roof (50) of the cyclone and from there further upwards according to the Fig. 1.

Device according to the Fig. 7. and 8.

This device is a two stage electro-filter cyclone which can be run both dry and wet. The gas enters the cyclone through the gas inlet (68) which has a device to set the gas in rotation. As examples of the way to set the gas in rotation are a tangential inlet or guiding vanes at the inlet. The gas flows then rotating downwards through a gap between the outer casing (73) and a cylindrical electrode (69). The electrode is connected into a high voltage unit and can have a smooth surface or tips as in the Fig. 1. or any other form, for example tips near the inlet for ionisation and then smooth surfaces for pushing charged particles away from them. The distance between (73) and (69) is chosen so small that a sure Corona effect occurs between them. When the gas has reached the lower end (70) of the electrode the gas in the outer sphere to rotate downwards at the same time as successively part of the gas turns upwards inside a <BR> <BR> cone (72).-The dust falls down through the outlet (71) of the cone and the gas enters a central<BR> pipe (64) through an opening (70). The pipe (64) is connected in the earth and isolated from the electrode (69) by an isolating ring (67). The gas rotates in the inner pipe (64) and the dust particles that have earlier been electrically charged by the electrode (69) are drawn against the pipe (64). The particles are affected both by the centrifugal and by the electrical forces. Over the upper end of the pipe (64) there is a gas outlet (77) which has a smaller diameter than the inner diameter of the pipe (64). The gas flow with the high dust content nearest the inner surface of the pipe turns outwards after the outlet opening of the pipe (64) and the cleaner gas flow from the central part of the pipe (64) continues upwards through the gas outlet (77). The dirty flow goes on rotating and is forced to change the direction downwards from the roof (78). The gas flows through the gap between the outer casing (75) and the guiding mantle (76). The dust is collected against the outer wall and falls downwards against the roof (74) of the lower cyclone part. The gas channels are so dimensioned that the velocity of the gas is decreasing outside the pipe (64). The static pressure of he gas is increasing because the velocity is decreasing. The gas turns success fully upwards in the space between (75) and (64) and starts flowing upwards near the outer wall of the pipe (64). The gas flows then between the guiding mantle (76) and the outer wall of the pip (64) to some gas channels (61) which guide the gas into the gas outlet (77).

The dust that has fallen over the roof (74) is emptied through the outlet (66) either through a feeding out valve or is sucked into a separator and the cleaned gas is directed back into the system through the inlet (65).

If the device is run wet water is injected in the gas in or before the inlet (68). If the device is run dry it is possible, if do decired, clean it by intermittent water injection before or in the inlet. In that case the outlet (71) and the pipe which is connected to (66) are closed by valves.

Other valves which are connected to these are opened and let the water be emptied to a water cleaning system.

Device according to the Fig. 9. and 10.

This device is a two-stage cyclone without the electro-filter function, but otherwise as the device according to Fig. 7 and 8.

Device according to the Fig. IL and 12.

This device is like the device according to Fig. 7 and 8, but it has electrodes as in the Fig. 1.

An electrode ring (81) is connected with a support (82) into the electrode (69). The outer wall (73) functions as a receiving electrode to the electrode ring (81) and ionises the gas that flows through the gap between the electrode ring (81) and the outer wall (73). A ring, receiving electrode (79), is connected with the support (80) into the outer wall under the electrode ring (81). The gas that flows through the gap between the electrode (69) and the receiving electrode (79) is ionised during this step. The rest of the function is then as in the device according to Fig. 7. and 8. For larger plants several electrodes and receiving electrodes are used for dividing the gas flow into several part flows where every part flow is ionised between its electrode ring and receiving electrode. With this type of electrodes the channel between (69) and (73) can be as large as asked and a sure Corona-effect can be created. This type of design can therefore be used in any size of cyclones without being forced to use a too high voltage for the electrical charging.

Device according to Fig. 13. and 14 This device consists of several cyclones according to the Fig. 7 and 8 or Fig. 9 and 10 or the Fig. 11 and 12. The gas enters through an inlet (109) into a space that is in contact with the inlet openings of the cyclone. A gas tight roof over and a floor under the inlet openings separate this space from the rest of the system. The cyclone elements (115) deliver dry dust.

This part of the device according to the Fig. 13 and 14 gives often an adequate cleaning because of the two stage cyclones and especially if the electro-filter part is build in the system. The ionisation of the gas can as an alternative be done in an ionisator before or at the inlet (109).

The dry dust is collected in the dust collector (111) from where it lets go out through the feeding out valve (114).

The dry multi-cyclone can be connected to a wet cleaning-and heat recovery unit as shown in the Fig. 13 and 14. The gas from the multi-cyclone is then directed through gas channels to a space under a collector (107) on which water I poured. Over the gas outlet of every channel there is a hat (117) which protects the gas channels against in falling water droplets. A diffuser plate (116) is placed around the outlet opening and forms together with the plane part of the hat a diffuser in which the rotation velocity of the gas is decreased and the static pressure is increased which means a certain reduction of the pressure drop in the cyclone.

In the upper part of the device the particles are collected and heat recovered on the same way as in the device according to the Fig. 1. A stack (101) is preferably placed on the top of the device. The whole device stays on support legs (112) on a fundament (113).

In this design the cyclone elements are placed inside a round outer casing (110) which can have the same, smaller or larger diameter than the diameter of the upper outer casing (124).

Device according to the Fig. 15 and 16.

This device is otherwise like the device according to the Fig. 13 and 14, but the cyclone elements are placed in an outer casing that is square, rectangular or have another not circular form. Over the cyclone elements there is an extra space where the gas is collected and from where it is directed through gas channels into the space under the collector (107). The diffuser ring (116) forms a diffuser between itself and the roof of the cyclone compartment.

Device according to the Fig. 17 and 18.

The incoming gas is ionised in this device with a device according to the Fig. 4 or 5. The ionisator can be placed horizontally as shown in the Fig. 17. or vertically or in any possible angle compared with the vertical direction. The rest of the device is like in the devises according to the fig. 13 and 14 or Fig. 15 and 16. If there are electrodes in the cyclones the dry cleaning is done in three stages that gives a high cleaning performance Device according to the Fig. 19 and 20.

This device has a similar system for ionisation as the device according to the Fig. 1, but the gas flows direction is upwards. The dry dust is collected in a ring formed channel around the outer casing of the gas channel (143). A wet cleaning stage can be connected after the dry stage for additional cleaning and heat recovery The gas is directed through the inlet (134) so that the gas rotates in the gas chamber (135). In this example the gas flows tangentially in, but the rotation can also be arranged with other helping means, for example with guiding vanes. The gas flows further upwards through a outer casing (143) which has the same as or smaller diameter than the diameter of the gas chamber (135). Inside this outer casing there is an electrode system that is isolated from the outer casing and is similar as described for the device according to the Fig. 1. The rings (131), (133), (148) and the rod (138) work as electrodes and can have tips in the electrodes with protecting pipes or other type of tips or be smooth rings. The supports (132), (136) and (149) keep the rings on correct position and charge them with high voltage from the central electrode rod (138). The rings (129), (130) and (139) work as receiving electrodes and are hold on place by supports (140), (141) and (142) which at the same time connect these rings to the earth via the outer casing (143) which works as a receiving electrode for the electrode ring (148). The gas is in this example ionised in four part flows, but the number of part flows can be chosen freely by dividing the channel to any number of part-channels with sufficient number of electrode rings and receiving electrodes.

When the gas has gone through the ionisation it goes on rotating through a strait part of the channel (143). Because the strait part of the channel in this example is a part of the stack it can be chosen long so that the particles get long time to be driven against the wall of the channel (143). After the strait part of the channel the gas flow is divided in two parts. The cleanest gas nearest the centre of the channel continues through the gas channel (150) and that part of the gas into which a part of the particles have been driven by centrifugal and electro- forces is directed in a gap between the outer casing (143) and the gas channel (150). From there the gas is pressed out through a number of gas channels (128) or a ring formed gap to a ring formed space between the outer casing (151) and the inner outer casing (143). The gas flows there rotating downwards and flows then through a gap between the guiding mantle (144) and the outer casing (151). The dust is pushed against the wall and falls down to the bottom of the ring formed channel. The gas changes direction upwards and flows through the gap between the guiding mantle (144) and the outer wall of the inner casing (143) into a number of gas channels (145) which are in connection with the inside of the gas channel (150). The static pressure inside the guiding mantle (144) is higher than on the inside of the gas channel (150) because the gas velocity inside the guiding mantle (144) has been reduced and the static pressure therefore has increased.

Device according to the Fig. 21.

This device is similar to the device according to the Fig. 11 and 12, but an electrode (152) is placed inside the central pipe (64) where it is working as a pushing electrode in the inner channel. This electrode can also be used for a second ionisation of the gas if electrode rings and receiving electrodes are used the same way as for example in the device according to the Fig. 1. or details (79) - (82) in the Fig. 11.

Device according to the Fig. 22.

This device is similar to the device according to the Fig. 19 and 20, but the outer casing (151) is lengthened and pushing electrodes (154) and (153) are placed in the centre of the outer <BR> <BR> casing (143). This gives the dust particles whichhave been ionised a longer time to be drawn<BR> to the inner surface of the outer casing (143) and they are also pushed by the electrodes (154) and (153) in that direction.

Device according to the Fig. 23.

This device is similar to the device according to the Fig. 22, but has additional ionisation rings inside the gas channel (150) similar to those shown in the Fig. 1. In this example a second high voltage unit is used for this ionisation, why the pushing electrode (153) is separated from the pushing electrode (154). Alternatively the same high voltage unit can be used for both systems for ionisation.

Device according to the Fig. 24.

This device is similar to the device according to the Fig. 15, but the gas is ionised a second time when it goes into the wet stage through the gas channel (157). The ionisation is done by an ionisator (158) which is similar to that one shown in the Fig 19. This type of ionisator can also be used in those cases where the rotation of the gas is not needed. In the case according to the Fig. 24 no separation of the dust particles is done through rotation in the wet part of the device why no device to get rotation for the gas is needed before the gas channel (157).

Device according to the Fig. 25-29.

This device is integrated in the stack and uses part or all of the total height of the stack for the cyclone function in two cyclones in series. The function is in principal the same as in the devises 9,11 and 21 with or without ionisation and pushing electrodes.

The whole device is shown in the Fig. 25. with a frame that is connected in a fundament (161) by a supporting ring (159) and a certain number of supports (160). If necessary the device is installed inside an outer casing where a ladder is available.

In the Fig. 26 the lower part of the device is shown with dust collectors (165) and (169) where dust from the cone (164) of the lower cyclone and from the dust channel (170) of the over cyclone are collected. Because the gas pressure in the collectors is different they are parted from each other through a wall (168) and the dust is emptied from the collectors through the feeding out valves (166) and (167).

In the Fig. 27. the principal design of the lower cyclone is shown in that case when ionisation and pushing electrodes are used to improve the particle collection. The device is working on the same way as in the Fig. 21.

In the Fig. 28. the principal design of the over cyclone is shown. The design is working on the same way as in the Fig. 21. The rotation velocity of the gas is decreased in the diffuser (189) for increasing the static pressure and for decreasing the pressure drop before the gas exits from the top of the stack. If the total height of the stack is not used for the cyclone a separate stack channel (190) is connected to direct the gas into the top of the stack.

-In the Fig. 29. the design for the gas inlet is shown for that case when the gas is entering tangentially through a slot. This design can be used in all devises with a cyclone. When the cyclone is used with reduced gas flow the entering velocity is reduced if the cross section of the slot is kept constant. Consequently the cleaning efficiency of the cyclone is then reduced.

In the design according to the Fig. 29. the width of the slot is reduced during part load by turning the throttle ring (191) round in the rotation bearing (192) so that it comes closer the outer wall of the inlet opening. The cross section of the inlet opening is then reduced and partly compensates the reduced performance of the cyclone at part load.

The same result is reached if a guiding ring is used to get the rotation for the gas. The guiding vanes are then supported so that they can be turned on same way as in the Fig. 29. so hat the width of the inlet opening can be reduced.

An alternative solution to reduce the inlet opening is to use a throttle vane which reduces the height of the opening at part load.

The size of the inlet opening can be automatically controlled by the following means : The opening is controlled so that the capacity of the blower is used, that means that the desired gas flow is created with full load for the blower.

'The dust emission is measured and the position of the throttle is controlled so that the desired emission is reached by the lowest use of electricity.

Device according to the Fig. 30.

In this device the gas flow is divided in two or more part-flows by one or more separating mantles (197). The inside surface of every separating mantle works as a collector for the dust particles. The particles are collected in scaling rings (205) which catches the gas flow near the inner surface of the mantle. A scaling ring (206) is also used for the surface inside the outer periphery (207). The gas with high dust content is directed from the scaling rings through pipes (198) to a separate space at the bottom of the devise with works as a cyclone. The cross section of the pipes is preferably increasing in the flow direction, but they can also have the same cross section all the way. The pipes are bended so that the outlets for the gas are directed tangentially in the same direction for all of them. The dust is pressed against the inner side of the outer wall of the space and falls down. The gas is then directed upwards through a central pipe (203). A guiding plate (204) is placed over this pipe and forms together with the top of the central pipe (203) a diffuser and increases the static pressure of the up going gas. Because the gas velocity in the small gas flow going upwards is low and the rotation velocity in the to the side turning down going gas flow is high the combination of (203) and (204) works as an ejector and sucks the up going gas flow out from the central pipe (203).

The cleaned gas can either be cleaned in one or several wet stages for example as in the device according to the Fig. 1, or let out further through an opening in the outer casing (200).

Electrodes and receiving electrodes (193) and pushing electrodes (195) and (208) can also be used in the device to additionally improve the cleaning performance for example on the same principal way as in the Fig. 21.

Device according to the Fig. 31.

In the Fig. 31 shows an alternative for the electrode ring in which the electrode is a thin thread (209) which is placed in a slot in the electrode ring (210). The electrode lies there protected against erosion and dirt. One or several slots are in the electrode ring. The slots can be separate, circular or in right angle against the flow direction as shown in the Fig. 31. They can also be placed with any desired angle compared with the flow direction, for example short separate slots in the flow direction. The slot can also build as a spiral which runs around the electro ring starting on the inlets side of the gas and stopping at the outlet side of the gas. The thread can have any desired cross section and have also spikes which help the discharging effect through the tips of the tags.

Device according to the Fig. 32.

In the Fig. 32 an alternative is shown where the electrodes (211) are placed outside the electrode ring (212) as one or several pointed rings. Instead of the rings the electrodes can also consist of rods connected to the electrode ring with any desired angle against the flow direction. A pointed sphere ring that runs as a spiral around the electrode ring starting on the inlet side of the gas and stopping at the outlet side of the gas is also a possibility. The pointed rings can also have broken point sphere with for example notches bended in an angle to the side to help the discharging through extra tips.

The devices described above are to be considered as examples over the possibilities the innovation gives why also other combinations than described here are possible. Parts of the system solutions are intended to be used as independent products. This concerns especially the ionisation and the different cyclone alternatives.

The cyclone designs without electrodes are intended to be used for fluid cleaning too.