PatentDe  


Dokumentenidentifikation EP1082175 26.10.2006
EP-Veröffentlichungsnummer 0001082175
Titel VERFAHREN UND EINRICHTUNG ZUM TRENNEN VON TEILCHEN AUS EINEM LUFTSTROM
Anmelder Metso Paper, Inc., Helsinki, FI
Erfinder LEIMU, Juha, FIN-20810 Turku, FI;
NORRI, Petri, FIN-20250 Turku, FI
Vertreter derzeit kein Vertreter bestellt
DE-Aktenzeichen 69933211
Vertragsstaaten AT, DE, ES, FR, GB, IT, SE
Sprache des Dokument EN
EP-Anmeldetag 25.05.1999
EP-Aktenzeichen 999265358
WO-Anmeldetag 25.05.1999
PCT-Aktenzeichen PCT/FI99/00446
WO-Veröffentlichungsnummer 1999061160
WO-Veröffentlichungsdatum 02.12.1999
EP-Offenlegungsdatum 14.03.2001
EP date of grant 13.09.2006
Veröffentlichungstag im Patentblatt 26.10.2006
IPC-Hauptklasse B03C 3/15(2006.01)A, F, I, 20051017, B, H, EP

Beschreibung[en]

The object of the present invention is a method and an apparatus according to the introductory parts of the independent claims presented below for separating solid or drop-like particles from air flows to be purified.

Then the invention relates particularly to a method and an apparatus where particles are separated from an air flow or a corresponding gas flow in a separator chamber or similar, by electrically charging the particles to be separated, e.g. by conventional high voltage techniques or ionisation, and by separating these electrically charged particles with the aid of a grounded collector surface or similar. Typically the separation occurs in an elongated cylindrical chamber, where at one end there is formed an air flow inlet and at the other end there is formed an outlet for the purified air flow which is separated from the particles. The electrode, ion generating means or similar which charges the particles is typically arranged in the central part of the separator chamber, so that it extends generally from the air flow inlet end to the purified air flow outlet end.

In conventional separators based on the electrical charge of the particles, as well as in electrical filters, the aim has been to obtain as low air flow velocities and as little turbulence as possible, so that the dust particles can be separated from the air flow in a smooth and controlled manner, and so that they are prevented from re-mixing with the air flow. The air flow is typically directed to the separator chamber via an inlet opening at the centre at one end of the chamber, and then the air flow is allowed to pass smoothly in the axial direction through the separator chamber, whereby the air flow and the separated particles uniformly fill the whole chamber, both at the centre and in the peripheral regions. Such conventional purification equipment must be made relatively large in order to provide the desired purification effect.

In conventional separators particles are separated from the air to be purified on all separator surfaces being in the way of the flow, both on the electrodes, on the structures supporting the electrodes and on the isolators arranged between the electrodes and the grounded collector surfaces. The particles accumulated on the surfaces will easily cause blockages which interfere with the free air flow through the separator chamber. On the other hand, piles of dry particles accumulated on the surfaces may from time to time begin to move again, as dust clouds, and form dusty air mixtures which impair the desired purification result. Further, layers accumulated particularly on the isolators may cause a short circuit between the electrodes and the grounded collector surfaces, which interferes with the operation of the isolator. Thus, due to the particles accumulated on the surfaces, the manageability and control of conventional purification equipment has often been difficult.

In addition to the small dust particles the air flow to be purified which flows through the separator chamber can sometimes also contain large particles or bodies which, when they hit the electrodes and stick to the electrode support structures, can both damage the structures and cause blockage.

Previously it has been proposed to use water spraying to wet the dust particles and bind them to each other in order to provide a better separation. However, the water will evaporate relatively rapidly from the moistened dust fog, and thus this wetting has not provided the desired result.

The german document DE 533 036 C describes a method and apparatus where the air flow to be purified is directed along a spiral path is a separator chamber so that particles in the air flow are separated due to the centrifugal force.

The American patent publication US 4,388,089 presents an improved separator into which the gas to be purified is supplied in the tangential direction from above, so that the gas is made to pass through the separator in a generally spiral path around a smooth and simple wire electrode on the central axis of the separator whereby the centrifugal force automatically directs a part of the particles toward the grounded walls of the separator. There is further arranged a water film on the separator walls which flows from the top downwards, and with this film the aim is to lead in a controlled manner the particles which have separated on the separator walls away from the separator, and an another aim is to prevent the particles from being remixed with the gas flow.

The capacity of a separator provided with a simple wire electrode is relatively low. In the above described case the use of other more efficient electrodes is limited i.a. by the fact that particles are more easily accumulated on their surfaces, which causes above mentioned blockage problems, or that the electrical field in their central part can be so low that the dust containing air flowing downwards in the central part will pass through without being purified. Particularly when the gas flow to be purified is large it may be difficult to prevent the particles in the central part of the separator, and at a distance from the water film to follow the gas downwards into the purified gas discharge at the bottom of the separator. Already due to the gravity force the particles tend to propagate directly downwards.

The objective of the present invention is thus to provide a new method and apparatus which are better than the previously known, in order to separate particles from an air flow.

The objective is to provide a method and an apparatus, where particularly the above mentioned drawbacks are minimised. Then an objective is particularly to provide a method and apparatus which minimise the accumulation of particles separated from the air flow on the electrodes, on the structures supporting the electrodes and on the insulators, and which minimise the problems caused by the accumulation.

An objective is to provide a method and an apparatus which enable the use of effective electrodes for charging the particles in the separator.

In order to achieve the above mentioned objectives the method and the apparatus according to the present invention are characterised in what is presented below in the characterising clauses of the independent claims.

The invention is particularly well suited for separating solid and drop-like particles from air flows to be purified in connection with the manufacturing of paper, paperboard, pulp or similar.

In a typical solution according to the invention the air flow to be purified is arranged to travel along a spiral path through an elongated vertical separator chamber, from an inlet at its bottom end to an outlet at its upper end, whereby the separator chamber acts as a separator where both electrical forces and the centrifugal force act on the particles and direct the particles toward a grounded collector surface at the periphery of the chamber. The collector surface is typically formed by the wall of the separator chamber, and the wall is grounded.

A typical separator according to the invention comprises a vertical cylindrical separator chamber, into whose central part an elongated electrode, ionising means or similar means with an open structure is arranged axially, which means can electrically charge the particles to be separated. The most different such electrodes can come into question where the electrode's horizontal open section has a large area, preferably over 90 %. The electrode can be formed for instance of vertical wire electrodes or similar which are placed adjacent each other at short mutual distances in the form of a circle, of a net formed by wire electrodes which is bent into the shape of a cylinder, or of a smooth narrow cylinder, which is provided with sharp points or pins which initiate the discharge.

According to the invention the air flow to be purified is arranged to travel around an electrode or similar along a spiral path directed upward from the bottom. Then particles are separated from the air flow when they are exposed to the action of the centrifugal force and/or when they are electrically charged and directed toward the walls of the separator chamber. In a preferred solution according to the invention the air flow is arranged to pass spirally upwards along the walls of the separator chamber, so that the particles or bodies in the air flow will pass over the electrodes, the structures supporting the electrodes and the isolators, mainly without touching them.

Further, a continuous water film or water skin is preferably arranged in the separator chamber so that it flows along the walls of the chamber and immediately binds the dust particles or other particles when they contact the water. The turbulence occurring in the spirally upwards flowing air flow furthers the particles coming into contact with the water film, whereby even a minor water film flowing along the walls is enough to bind the dust. The particles brought into contact with the water film are wetted and bound to the water film, and cannot again mix with the air flow and form harmful dust-air mixtures. The water film flows downwards and moves the impurities stuck to it into the lower part of the separator chamber and discharges them from the separator.

The rotary motion of the air flow in the separator chamber results in that the main part of that air flow which is brought into contact with the electrodes, with the structures supporting the electrodes and with the isolators, is relatively clean and will not cause substantial accumulation of dirt on the structures. With the solution according to the invention it is possible to ensure that the electrodes and other surfaces at the centre of the separator chamber will be kept clean by creating conditions in the central part of the separator chamber around the electrode surfaces or similar for a downward directed flow of clean gas which washes the electrodes. The electrodes or electrode surfaces are designed with such a structure that they do not substantially hinder the gas flow at the region of the electrodes, but enable the clean gas to flow in the central part of the separator from the top of the separator chamber downwards. The clean gas can flow almost straight downwards, or in a small spiral downwards. In the solution according to the invention we have surprisingly realised to utilise the fact that in a separator where the supplied gas is brought to flow spirally upwards there is formed at the centre of the spiral flow a downward directed flow of clean gas, as far as there is arranged an open space for the clean gas flow in the central part of the separator. In the solution according to the invention the open space is arranged in the central part of the separator by arranging at the central part of the separator such electrodes which have a cross-section which is as open as possible, which in other words causes as little hindrance to the flow as possible. In the case according to the invention the open area of the electrode area is preferably over 90 %.

Thus in the solution according to the invention it is ensured that the electrodes are kept clean by arranging an air flow in the separator chamber so that at the centre of the spirally upward flowing air flow between the electrode or similar and the wall of the separator chamber we allow the generation of a smaller downward directed flow of clean air. The downward flowing clean air washes the surfaces of the electrodes arranged in the central part of the separator chamber and removes any particles accumulated on them, and directs these particles downward to the particle discharge and/or directs them outward toward the spiral air flow where the particles will be subject to a new separating process. The flow of clean air is less than 30 % of the air flow to be purified. Often a substantially smaller clean air flow is sufficient to keep the electrode surfaces clean.

In order to ensure the open area the electrodes can preferably be made of wire electrodes by arranging them at short mutual distances, or by bending them into electrode assemblies with a desired form, for instance a net form, however, leaving space between the electrode surfaces for the gas flow, or by forming sharp points or pins of the electrodes which are fastened to the support structure at the centre of the isolator.

The spiral flow of the air to be purified is provided for instance by supplying the air flow in a tangential direction into the separator chamber from an inlet at the bottom part of the chamber. On the other hand the air flow can also be supplied axially from an inlet opening or channel arranged at the centre of the chamber when one or more blades or similar are arranged in the opening or channel, whereby these blades bring the air flow to pass along a spiral path in the chamber around the imaginary axis of the chamber.

The air flow is supplied into the separator from its lower part so that the air flow rotates against the internal surface of the cylinder. The air travels in a screw motion from the inlet toward the outlet. The rotational motion ensures a stable flow and ensures the same retention time in the separator for the whole air flow. Any large bodies in the air flow will hit and stick to the wall of the cylinder acting as a collector surface immediately when they come into the separator, without causing any harm.

Due to the rotational motion of the air flow the distance which the air flow travels in the separator chamber is many-fold, typically 3 to 6 times, compared to the length of the separator chamber, or compared to the distance which the air flow travels in conventional separators operating with an axial flow.

The invention is described in more detail below with reference to the enclosed drawings where

Figure 1
shows as an example a diagram of a purification apparatus using a separator according to the invention;
Figure 2
shows schematically and partly opened an exemplary separator according to the invention;
Figure 3
shows schematically a cross-section of another exemplary separator according to the invention;
Figure 4
shows schematically a modification of the separator according to figure 3; and
Figures 5 to 7
show schematically electrodes which are suitable for a separator according to the invention.

Figure 1 shows an air purification apparatus 10 arranged in connection with a paper machine, where dust particles are separated from the air by charging the particles electrically, by conventional high voltage techniques, by electrical ionising techniques, or some other corresponding technique. The air purification apparatus comprises a separator 12, inlet piping 14 for the air to be purified, discharge piping 16 for the purified air, discharge piping 18 for the separated particles, a power source 20, and spray water piping 22.

The separator 12, i.e. the actual air purifier, comprises a vertical cylindrical separator chamber 24, which has an inlet 26 for the air to be purified, an outlet 28 for the purified air, and a discharge opening 30 for the separated particles. The separator chamber has typically a height of 2 to 9 m, suitably 3 - 7 m, and a diameter of 0.5 to 3 m, suitably 1 to 2 m, and is generally a chamber made of stainless steel, with a maximal flow-through of about 0.3 to 10 m3/s, typically 1 to 5 m3/s.

In the central part of the separator there is arranged an electrode or ion generating means 32, which comprises several consecutive sections 34, to each of which there is attached a plurality of points for generating a corona discharge. The electrode is connected to a power source 20 by a conductor 36, whereby the voltage of the power source is for instance 100 to 150 kV. The wall 38 of the separator is grounded, whereby an electrical field is generated between the electrode and the grounded wall, which field will charge the particles moving in the electrical field and bring the particles to move toward the wall.

Air to be purified is supplied to the separator from different locations 40, 40', for instance in a paper machine, such as from the wire section, from the drying section, from the slitter-winder and from the coating machine, so that the air is purified from i.a. water drops, fibrous pulp, additives and other dust. It is often necessary to remove dust, as well as water drops, from the air before it is reused or discharged to the environment. Also so called clean external air can be purified in a separator according to the invention. The air to be purified is conveyed through the separator with the aid of a blower 42 arranged in the discharge piping 16 for the purified air.

In the separator according to the invention shown in figure 1 the air to be purified is supplied in the tangential direction into the separator so that the air flows along a spiral path in the separator chamber 24 along its walls 38 from the inlet 26 at its lower part to the outlet 28 at its upper part. The air flow can be directed to the separator at a high velocity 10 to 20 m/s, typically 15 m/s, whereby the velocity of the air flow is substantially higher than the air flow velocity in conventional corresponding separators, where it is maximally 3 to 4 m/s, even less than 1 m/s. On the other hand the retention time of the air flow in the separator is generally as long as in the conventional separators.

Due to the tangential inlet, large particles in the air flow will hit the separator wall immediately at the lower part of the separator where they are separated from the air flow. Air and any smaller particles left in it will flow forward close to the wall 38 in the electrical field between the electrode 32 and the grounded wall 38. The particles in the air flow are charged in the electrical field, whereby the combination of the centrifugal force and the electrical field causes the particles to be separated from the air flow and their transport toward the grounded outer periphery of the separator, in other words its wall, and to stick to the wall. Because the air flow is directed to travel along the grounded wall, and because there are no other structures between the wall and the air flow, the particles separated from the air flow can very easily travel, either due to the centrifugal force or to the electrical forces or to their combined effect, so that they contact the grounded wall and stick to it. The purified air which is free of particles is discharged from the outlet 28.

The particles stuck on the wall 38 are removed by washing water jets 44 connected to the water piping 22, whereby the jets form a continuous water film flowing downward along the walls 38 and ensure that the particles are separated from the air flow. In the solution according to the invention it is not generally necessary that the air which contains particles and flows in the separator chamber is wetted with water jets or a water spray. The water is sprayed mainly directly toward the walls of the separator chamber where the water forms a water film which binds the particles to the wall. The water film and the particles in it are discharged from the separator through the opening 30 formed at the centre of the bottom 46 in the separator. The discharge of the particles from the bottom 46 of the separator can be made more effective by spraying from time to time water on the bottom, for instance during about 30 seconds in intervals of about 20 minutes, from spraying nozzles 48 which are located at the bottom and also connected to the water piping 22. In many cases it is possible to use white water as washing water.

Figure 2 which uses the same reference numerals as figure 1 where applicable shows a typical separator according to the invention which is partly opened. Five electrode sections 34 are axially mounted in the separator, whereby the sections are formed by annular support structures mounted coaxially on the axis of the separator, and by a plurality of, for instance 4 to 20, radially arranged pin electrodes 50. Via a conductor 36 the electrode is connected to the power source 20 and a controller, not shown in more detail. The conductor is protected from the grounded wall structure 38 by an isolator 52.

The inlet 26 of the air to be purified is arranged on the periphery of the separator to direct the air to be purified in a tangential direction into the separator. In the inlet the air flow to be purified is brought into a spiral motion, whereby the particles in the air flow are directed toward the walls 38 of the separator and do not in any particular amount come into contact with the sections 34 of the electrode, which thus will stay clean and intact. Also the isolator 52 is kept free of particles, and there is no risk of sparking from the electrodes 50 via the isolator 52 to the grounded wall 38.

Washing water is sprayed on the separator walls from an annular water pipe 54 provided with spray nozzles 44 and arranged coaxially with the separator in the upper part of the separator. At the bottom of the separator there is also arranged an angular water pipe 56 from which washing water can be sprayed from time to time in order to direct the particles accumulated on the bottom 46 toward the particle discharge opening 30. In order to discharge the particles there is not necessarily required an angular water pipe at the bottom, but there may be arranged a required number of, for instance 3, separate water nozzles for the spraying of washing water.

Figure 3 shows another typical separator according to the invention for removing particles from an air flow. The same reference numerals as in the figures 1 and 2 are used where applicable also in figure 3. In the separator chamber 24 of figure 3 the air inlet opening 26' is arranged axially at the centre of the bottom 46 of the separator. In order to bring the air flow into a spiral motion blades 58 are arranged in a channel 26" arranged in the inlet opening 26', whereby these blades bring the air flow into a rotary motion. Due to the blades the air flow in this separator will have a spiral form as in the separators presented in the figures 1 and 2. In the separator 12 the air flow will move around the electrode 32 so that the particles will not generally come into contact with the electrode or with the structures supporting the electrode. In the solution according to figure 3 the particle discharge opening 30' is formed in the lower part of the separator wall 38 or in the bottom 46, i.a. adjacent the inlet opening 26' for the air flow.

Figure 3 shows also the air flow 57 to be purified which is upwardly directed in a spiral flow, and from which particles are separated and transported toward the wall 38, due to the effect of either the centrifugal force or the electrical force. The figure 3 further shows, at the centre of the spirally upwardly flowing air flow which is to be purified, another substantially smaller clean air flow 59 which travels downward in a spiral flow, whereby this clean air flow washes the electrode 32 in order to keep it clean. The washing clean air flow is substantially smaller than the air flow to be purified, i.e. typically its volume is less than 30 % of the air flow to be purified. The use of a washing air flow enables the use of many different effective electrode constructions as the air washing prevents dust accumulations on their surfaces. A similar electrode washing is advantageously arranged also in the apparatuses according to the invention shown in the figures 1 and 2.

Figure 4 shows a separator 12 according to figure 3, however, now the separator has two sections 60, 62, so that the electrode 32 is mounted only in the upper section 60 of the separator, whereby the lower section 62 of the separator only operates as a centrifugal separator. Blades 58 are mounted in the inlet opening formed in the lower part of the separator, whereby the blades bring the air flow supplied to the separator into a spiral motion. Then in the lower section 62 of the separator particles which can be separated from the air flow by the centrifugal force are separated, and the smaller particles follow the air flow into the upper section 60 of the separator. In the upper section of the separator the smaller particles are separated electrostatically, as the air flow travels between the electrode 32 and the grounded wall 38, as was described in connection with figures 1 to 3.

In this case it is possible to arrange a separate outlet 64 for coarse particles in the lower section 62 and an outlet 66 for fine particles in the upper section 60 of the separator, whereby particles of different type can be separated from each other, which in some cases may be useful.

Figures 5 to 7 show different electrodes which conceivably can be used in a solution according to the invention. The cylindrical electrode of figure 5 is formed by a cylindrical surface 70, in which there are formed points 72 in order to create a corona discharge. The electrode 74 of figure 6 is formed of thin wire electrodes 76 combined into a net form. The net is bent into the form of a cylinder. The electrode 78 of figure 7 is formed by a number of vertical wire electrodes 80, which are connected adjacent each other on a cylindrical periphery so that they are axially directed. The electrodes have an open structure, so that they enable the use of a vertical washing air flow at the centre of the separator in order to keep the electrodes clean.

The advantage of the separator solution according to the invention compared to what is previously known can be seen i.a. in that

  • a re-mixing of purified air and separated particles can be avoided when the inlet of the air to be purified is arranged at the lower part of the separator and the outlet of the purified air at the upper part of the separator;
  • when the air inlet is arranged at the lower part of the separator the air to be purified and the water film flowing along the walls of the separator can be arranged to flow in opposite directions, so that the air which contains impurities in the lower part of the separator meets water which contains most impurities, and so that the purified air in the upper part of the separator meets clean water;
  • more effective electrode solutions than simple wire electrodes can be used as electrodes when the air flow is arranged so that a small part of clean air flows axially downward in the central part of the separator and washes the electrodes, considering also that the capacity of the wire electrodes is relatively low; and that
  • the use of larger electrodes enables the use of separators having a larger size.

The air flow purifiers according to the invention shown in figures 1 to 4 operate effectively because they utilise a top-separator based on mass forces in combination with electrical separation. A separator according to the invention can provide a separation which is even higher than 99 %, which enables the purified air to be utilised also in demanding applications. A top-separator can by itself separate water drops having a size over about 100 microns. On the other hand, the separating capacity of a separator based on electrical separation reaches particles well below 1 micron. Thus an apparatus according to the invention is intended to purify the most different impurities from the air flow or corresponding gas flow, including liquid drops and solid particles, with a wide particle size distribution range.

Due to the low pressure difference of the separator the energy consumption of the blower in an apparatus according to the invention is low compared to previous solutions. The energy consumption required for the electrical charging or ionisation in a typical separator according to the invention is maintained at a level of about 1 to 3 kW. In a solution according to the invention the water consumption is also low, typically about 25 to 30 litres/minute, because water is not required per se for separating dust from the air, but only for removing the particles from the separator.

The invention is not intended to be limited to the exemplary embodiments presented above, but on the contrary, the intention is to apply it widely within the inventive idea defined in the enclosed claims.


Anspruch[de]
Verfahren zum Trennen von festen oder tropfenartigen Partikeln aus einer Luftströmung oder dergleichen, die zu reinigen ist, wobei bei dem Verfahren - die zu reinigende Luftströmung zu einer Separatorkammer (24) geliefert wird und so gerichtet wird, dass sie entlang einer spiralartigen Bahn zumindest durch einen Teil der Separatorkammer so läuft, dass ein Teil von den Partikeln in der Luftströmung aufgrund der Zentrifugalkraft abgetrennt wird; - die Luftströmung so eingerichtet ist, dass sie durch die Separatorkammer (24) zwischen einerseits zumindest einer Elektrode, einer Ionenerzeugungseinrichtung oder dergleichen (32) und andererseits einer geerdeten Kollektorfläche (38), die zwischen dem Einlassende von der Separatorkammer und ihrem Auslassende angeordnet sind, so strömt, dass Partikel aufgeladen werden, von der Luftströmung abgetrennt werden und an der Kollektorfläche angesammelt werden, - die zu reinigende Luftströmung so eingerichtet ist, dass sie entlang einer nach oben gerichteten Spiralbahn um die Elektrode, die Ionenerzeugungseinrichtung oder dergleichen (32) in zumindest einem Teil der Separatorkammer strömt, gekennzeichnet durch - in der Separatorkammer erfolgendes Nutzen einer Elektrode, einer Ionenerzeugungseinrichtung oder dergleichen mit einem offen Aufbau, wobei ermöglicht wird, dass eine geringfügige gereinigte Luftströmung nach unten in dem mittleren Teil der Spiralbahn von der zu reinigenden Luftströmung läuft, wodurch die geringfügige Luftströmung die Elektrode, die Ionenerzeugungseinrichtung oder dergleichen wäscht. Verfahren gemäß Anspruch 1,

dadurch gekennzeichnet, dass

die zu reinigende Luftströmung in einer tangentialen Richtung in die Separatorkammer von einem Einlass (26) an ihrem Bodenteil geliefert wird, - eine gereinigte Luftströmung, die weniger als 30 % der zu reinigenden Luftströmung beträgt, so eingerichtet ist, dass sie in dem mittleren Teil von der Separatorkammer in einer Spiralbahn nach unten läuft, wodurch sie die Elektrode, die Ionenerzeugungseinrichtung oder dergleichen wäscht.
Verfahren gemäß Anspruch 1,

dadurch gekennzeichnet, dass

die zu reinigende Luftströmung in die Separatorkammer durch einen Luftströmungseinlasskanal (26") oder dergleichen geliefert wird, der hauptsächlich axial in der Separatorkammer angeordnet ist, wobei ein oder mehrere Flügel (58) oder dergleichen in dem Kanal oder dergleichen angeordnet sind, um die Luftströmung dazu zu bringen, dass sie entlang einer Spiralbahn läuft.
Verfahren gemäß Anspruch 1,

dadurch gekennzeichnet, dass

die zu reinigende Luftströmung so gerichtet wird, dass sie durch die Separatorkammer entlang einer Spiralbahn hauptsächlich von dem Einlass (26, 26') an einem Ende von der Separatorkammer zu einem Auslass (28) an ihrem anderen Ende und zwischen einerseits der Elektrode, der Ionenerzeugungseinrichtung oder dergleichen (32), die axial in der Separatorkammer angeordnet ist, und andererseits die zylindrische Wand von der Separatorkammer, die die geerdete Kollektorfläche (38) ausbildet, so läuft, dass die Entfernung, die von der Luftströmung in der Separatorkammer zurückgelegt wird, ein Vielfaches im Vergleich zu der Länge der Separatorkammer ist.
Verfahren gemäß Anspruch 1,

dadurch gekennzeichnet, dass

die Kollektorfläche kontinuierlich mit Wasserstrahlen (44) benetzt wird, um die Partikel, die sich an der Kollektorfläche angesammelt haben, zu benetzen, und dass der Boden von der Separatorkammer zumindest von Zeit zu Zeit mit einem Wasserstrahl (48) besprüht wird, um die Partikel, die sich an dem Boden angesammelt haben, zu einer Abgabeöffnung in dem Boden zu richten.
Gerät zum Trennen von festen oder tropfenartigen Partikeln von einer zu reinigenden Luftströmung in Verbindung mit einer Papierherstellung oder Pulpenherstellung, wobei das Gerät eine Separatorkammer (24) aufweist, die folgendes hat: - zumindest eine Elektrode, eine Ionenerzeugungseinrichtung oder dergleichen (32), die hauptsächlich axial in der Separatorkammer angeordnet ist für ein elektrisches Aufladen von Partikeln in der Luftströmung, - zumindest eine geerdete Kollektorfläche (38) für ein Sammeln der Partikeln, die sich von der Luftströmung abgetrennt haben und die elektrisch aufgeladen worden sind, und - an einem Ende einen Einlass (26, 26') für die zu reinigende Luftströmung und einen Auslass (28) an dem andere Ende für die gereinigte Luftströmung, wobei der Einlass an dem unteren Teil der Separatorkammer angeordnet ist und eine Einrichtung hat für ein Richtung der Luftströmung in derartiger Weise, dass sie von dem Einlass zu dem Auslass entlang einer Spiralbahn um die Elektrode, die Ionenerzeugungseinrichtung oder dergleichen herum läuft, - wobei die zumindest eine Elektrode axial in dem mittleren Teil der Separatorkammer angeordnet ist, dadurch gekennzeichnet, dass - die zumindest eine Elektrode, Ionenerzeugungseinrichtung oder dergleichen einen offen Aufbau hat, so dass sie im Wesentlichen eine Gasströmung an dem mittleren Teil von dem Separator von der Oberseite der Separatorkammer nach unten nicht behindert, und so dass sie ermöglicht, dass eine Waschluftströmung in den mittleren Teil des Separators verwendet wird, um die Elektrode, die Ionenerzeugungseinrichtung oder dergleichen sauber zu halten, - wobei die Elektrode, die Ionenerzeugungseinrichtung oder dergleichen dann beispielsweise ausgebildet ist durch: vertikale Drahtelektroden, die zu einer Kreis- oder Netzform angeordnet sind; einen schmalen Zylinder, der mit Punkten oder Zapfen versehen ist, die die Entladung initiieren; oder durch Nadelelektroden, die radial an dem Stützaufbau angeordnet sind. Gerät gemäß Anspruch 6,

dadurch gekennzeichnet, dass

die Einrichtung zum Richten der Luftströmung einen Einlass (26) für die Luftströmung aufweist, der an dem Umfang der Separatorkammer angeordnet ist, um die Luftströmung in einer tangentialen Richtung in die Separatorkammer zu richten.
Gerät gemäß Anspruch 6,

dadurch gekennzeichnet, dass

die Einrichtung zum Richten der Luftströmung einen Einlasskanal (26") oder dergleichen aufweist, der hauptsächlich axial an einem Ende von der Separatorkammer angeordnet ist und mit zumindest einem Flügel (58) versehen ist, der die Luftströmung dazu bringt, dass sie entlang einer Spiralbahn um die imaginäre Achse der Separatorkammer läuft.
Gerät gemäß Anspruch 6,

dadurch gekennzeichnet, dass

die Wände (38) von der Separatorkammer geerdet sind und dass die Einrichtung zum Richten der Luftströmung eine Einrichtung (26, 58) zum Richten der Luftströmung in derartiger Weise aufweist, dass sie entlang einer Spiralbahn entlang den Wänden (38) der Separatorkammer von einem Einlass (26) an einem Ende der Separatorkammer zu einem Auslass (28) an ihrem anderen Ende läuft.
Gerät gemäß Anspruch 6,

dadurch gekennzeichnet, dass

die Separatorkammer eine vertikale zylindrische Kammer ist, an deren Mitte eine Elektrode, eine Ionenerzeugungseinrichtung oder dergleichen (32) axial angeordnet ist, wobei ein Luftströmungeinlass (26) an dem Bodenteil der Separatorkammer angeordnet ist und ein Luftströmungsauslass (28) an ihrem oberen Teil angeordnet ist.
Gerät gemäß Anspruch 6,

dadurch gekennzeichnet, dass

die Separatorkammer eine vertikale Kammer ist und dass eine Abgabeöffnung (30) für ein Material, das aus der Luftströmung abgetrennt wird, an dem mittleren Teil des Bodens von der Separatorkammer angeordnet ist.
Gerät gemäß Anspruch 6,

dadurch gekennzeichnet, dass

die Separatorkammer einen vertikale Kammer mit einer Höhe zwischen 2 und 9 m, wobei 3 bis 7 m am besten geeignet sind, und mit einem Durchmesser zwischen 0,5 und 3 m ist, wobei 1 bis 2 m am besten geeignet sind.
Anspruch[en]
A method for separating solid or drop-like particles from an air flow or similar to be purified, in which method - the air flow to be purified is supplied to a separator chamber (24) and directed to travel along a spiral path at least through a part of the separator chamber so that a portion of the particles in the air flow are separated due to the centrifugal force; - the air flow is arranged to flow through the separator chamber (24) between on one hand at least an electrode, ion generating means or similar (32) and on the other hand a grounded collector surface (38) arranged between the inlet end of the separator chamber and its outlet end, so that particles are charged, separated from the air flow and accumulated on the collector surface, - the air flow to be purified is arranged to flow along an upwardly directed spiral path around the electrode, ion generating means or similar (32) in at least a part of the separator chamber, characterised by - utilizing in the separator chamber an electrode, ion generating means or similar with an open structure, allowing a small purified air flow to travel downward in the central part of the spiral path of the air flow to be purified, whereby the small air flow washes the electrode , ion generating means or similar. A method according to claim 1, characterised in that - the air flow to be purified is supplied in a tangential direction into the separator chamber from an inlet (26) in its bottom part, and that - a purified air flow, which is less than 30 % of the air flow to be purified, is arranged to travel downward in the central part of the separator chamber in a spiral path, whereby it washes the electrode, ion generating means or similar. A method according to claim 1, characterised in that the air flow to be purified is supplied into the separator chamber through an air flow inlet channel (26") or similar arranged mainly axially in the separator chamber, whereby one or more blades (58) or similar are arranged in the channel or similar for bringing the air flow to travel along a spiral path. A method according to claim 1, characterised in that the air flow to be purified is directed to travel through the separator chamber along a spiral path, mainly from the inlet (26, 26') at one end of the separator chamber to an outlet (28) at its other end, and between on one hand the electrode, ion generating means or similar (32) arranged axially in the separator chamber and on the other hand the cylindrical wall of the separator chamber forming the grounded collector surface (38), so that the distance travelled by the air flow in the separator chamber is many-fold compared to the length of the separator chamber. A method according to claim 1, characterised in that the collector surface is continuously wetted with water jets (44) in order to wet the particles accumulated on the collector surface, and that the bottom of the separator chamber is sprayed at least from time to time with a water jet (48) in order to direct the particles accumulated on the bottom into a discharge opening in the bottom. An apparatus for separating solid or drop-like particles from an air flow to be purified in connection with paper or pulp manufacturing, the apparatus comprising a separator chamber (24) having - at least one electrode, ion generating means or similar (32) arranged mainly axially in the separator chamber for electrically charging particles in the air flow, - at least one grounded collector surface (38) for collecting the particles which are separated from the air flow and electrically charged, and - at one end an inlet (26, 26') for the air flow to be purified, and an outlet (28) at the other end for the purified air flow, the inlet being arranged at the lower part of the separator chamber and having means for directing the air flow to travel from the inlet to the outlet along a spiral path around the electrode, ion generating means or similar, - said at least one electrode is arranged axially in the central part of the separator chamber, characterised in that - said at least one electrode, ion generating means or similar has an open structure, so that it does not substantially hinder a gas flow at the central part of the separator from top of the separator chamber downwards, and so that it enables a washing air flow to be used in the central part of the separator in order to keep the electrode, ion generating means or similar clean, - whereby the electrode, ion generating means or similar is then formed for instance by: vertical wire electrodes arranged into a circle or net form; a narrow cylinder provided with points or pins which initiate the discharge; or by pin electrodes arranged radially on the support structure. An apparatus according to claim 6, characterised in that the means for directing the air flow comprise an inlet (26) for the air flow which is arranged at the periphery of the separator chamber in order to direct the air flow in a tangential direction into the separator chamber. An apparatus according to claim 6, characterised in that the means for directing the air flow comprise an inlet channel (26") or similar arranged mainly axially at one end of the separator chamber and provided with at least one blade (58) which brings the air flow to travel along a spiral path around the imaginary axis of the separator chamber. An apparatus according to claim 6, characterised in that the walls (38) of the separator chamber are grounded, and that the means for directing the air flow comprise means (26, 58) for directing the air flow to travel along a spiral path along the walls (38) of the separator chamber, from an inlet (26) at one end of the separator chamber to an outlet (28) at its other end. An apparatus according to claim 6, characterised in that the separator chamber is a vertical cylindrical chamber, at the centre of which an electrode, ion generating means or similar (32) is axially arranged, whereby an air flow inlet (26) is arranged at the bottom part of the separator chamber and an air flow outlet (28) is arranged at its upper part. An apparatus according to claim 6, characterised in that the separator chamber is a vertical chamber, and that a discharge opening (30) for material separated from the air flow is arranged in the central part of the bottom of the separator chamber. An apparatus according to claim 6, characterised in that the separator chamber is a vertical chamber with a height between 2 and 9 m, most suitably 3 to 7 m, and with a diameter between 0.5 and 3 m, most suitably 1 to 2 m.
Anspruch[fr]
Procédé d'extraction de particules solides ou sous forme de gouttelettes d'un écoulement d'air ou analogue à purifier, dans lequel : - l'écoulement d'air à purifier est amené à une chambre d'extraction (24) et dirigé pour circuler le long d'une voie hélicoïdale au moins à travers une partie de la chambre d'extraction de façon à ce qu'une partie des particules présentes dans l'écoulement d'air soient séparées en raison de la force centrifuge ; - l'écoulement d'air est conçu pour circuler à travers la chambre d'extraction (24) entre d'une part au moins une électrode, un dispositif générateur d'ions ou analogue (32) et d'autre part une surface collectrice reliée à la terre (38) agencée entre l'extrémité d'entrée de la chambre d'extraction et son extrémité de sortie, de sorte que les particules soient chargées, extraites de l'écoulement d'air et s'accumulent sur la surface collectrice, - l'écoulement d'air à purifier est conçu pour s'écouler le long d'une voie hélicoïdale dirigée vers le haut autour de l'électrode, le dispositif générateur d'ions ou analogue (32) dans au moins une partie de la chambre d'extraction, caractérisé par - l'utilisation dans la chambre d'extraction d'une électrode, d'un dispositif générateur d'ions ou analogue avec une structure ouverte, permettant à un faible écoulement d'air purifié de circuler vers le bas dans la partie centrale de la voie hélicoïdale de l'écoulement d'air à purifier, moyennant quoi le faible écoulement d'air nettoie l'électrode, le dispositif générateur d'ions ou analogue. Procédé selon la revendication 1, caractérisé en ce que : - l'écoulement d'air à purifier est amené dans une direction tangentielle dans la chambre d'extraction depuis une entrée (26) dans sa partie inférieure, et en ce que - un écoulement d'air purifié, qui représente moins de 30 % d'écoulement d'air à purifier, est conçu pour circuler vers le bas dans la partie centrale de la chambre d'extraction dans une voie hélicoïdale, moyennant quoi il nettoie l'électrode, le dispositif générateur d'ions ou analogue. Procédé selon la revendication 1, caractérisé en ce que l'écoulement d'air à purifier est amené dans la chambre d'extraction à travers une voie d'entrée d'écoulement d'air (26") ou analogue agencée principalement axialement dans la chambre d'extraction, moyennant quoi une ou plusieurs aubes (58) ou analogues sont agencées dans la voie ou analogue pour amener l'écoulement d'air à circuler le long d'une voie hélicoïdale. Procédé selon la revendication 1, caractérisé en ce que l'écoulement d'air à purifier circule à travers la chambre d'extraction le long d'une voie hélicoïdale principalement depuis l'entrée (26, 26') à une extrémité de la chambre d'extraction vers une sortie (28) à son autre extrémité, et entre d'une part l'électrode, le dispositif générateur d'ions ou analogue (32) agencés axialement dans la chambre d'extraction et d'autre part la paroi cylindrique de la chambre d'extraction formant la surface collectrice reliée à la terre (38) de sorte que la distance parcourue par l'écoulement d'air dans la chambre d'extraction soit multiple comparé à la longueur de la chambre d'extraction. Procédé selon la revendication 1, caractérisé en ce que la surface collectrice est en permanence humidifiée avec des jets d'eau (44) afin d'humidifier les particules accumulées sur la surface collectrice, et en ce que le fond de la chambre d'extraction soit aspergé au moins de temps en temps avec un jet d'eau (48) afin de diriger les particules accumulées sur le fond dans une ouverture d'évacuation dans le fond. Appareil pour extraire les particules solides ou sous forme de gouttelettes d'un écoulement d'air à purifier en relation avec une fabrication de papier ou pâte à papier, l'appareil comprenant une chambre d'extraction (24) ayant - au moins une électrode, un dispositif générateur d'ions ou analogue (32) agencé principalement axialement dans la chambre d'extraction pour charger électriquement les particules dans l'écoulement d'air, - au moins une surface collectrice reliée à la terre (38) pour collecter les particules extraites de l'écoulement d'air et électriquement chargées, et - à une extrémité une entrée (26, 26') pour l'écoulement d'air à purifier, et une sortie (28) à l'autre extrémité pour l'écoulement d'air purifié, l'entrée étant agencée à la partie inférieure de la chambre d'extraction et dotée d'un dispositif pour amener l'écoulement d'air à circuler de l'entrée à la sortie le long d'une voie hélicoïdale autour de l'électrode, du dispositif générateur d'ions ou analogue. - ladite au moins une électrode est agencée axialement dans la partie centrale de la chambre d'extraction, caractérisé en ce que - ladite au moins une électrode, le dispositif générateur d'ions ou analogue ont une structure ouverte, de façon à ne pas entraver sensiblement un écoulement de gaz à la partie centrale de l'extracteur depuis la partie supérieure de la chambre d'extraction vers le bas, et de façon à permettre d'utiliser un écoulement d'air de nettoyage dans la partie centrale de l'extracteur afin de maintenir propres l'électrode, le dispositif générateur d'ions ou analogue, - moyennant quoi l'électrode, le dispositif générateur d'ions ou analogue sont ensuite formés par exemple par : des électrodes en fil verticales agencées sous forme d'un cercle ou sous forme de filet ; un cylindre étroit doté de points ou de broches qui initient la décharge : ou des électrodes à broches agencées radialement sur la structure du support. Appareil selon la revendication 6, caractérisé en ce que le dispositif pour diriger l'écoulement d'air comprend une entrée (26) pour l'écoulement d'air qui est agencée à la périphérie de la chambre d'extraction afin de diriger l'écoulement d'air dans une direction tangentielle dans la chambre d'extraction. Appareil selon la revendication 6, caractérisé en ce que le dispositif pour diriger l'écoulement d'air comprend une voie d'entrée (26") ou analogue agencée principalement axialement à une extrémité de la chambre d'extraction et dotée d'au moins une aube (58) qui amène l'écoulement d'air à circuler le long d'une voie hélicoïdale autour de l'axe imaginaire de la chambre d'extraction. Appareil selon la revendication 6, caractérisé en ce que les parois (38) de la chambre d'extraction sont reliées à la terre, et que le dispositif pour diriger l'écoulement d'air comprend un dispositif (26, 58) pour amener l'écoulement d'air à circuler le long d'une voie hélicoïdale le long des parois (38) de la chambre d'extraction, depuis une entrée (26) à une extrémité de la chambre d'extraction vers une sortie (28) à son autre extrémité. Appareil selon la revendication 6, caractérisé en ce que la chambre d'extraction est une chambre cylindrique verticale, au centre de laquelle une électrode, un dispositif générateur d'ions ou analogue (32) est agencé axialement, moyennant quoi une entrée d'écoulement d'air (26) est agencée à la partie de fond de la chambre d'extraction et une sortie d'écoulement d'air (28) est agencée à sa partie supérieure. Appareil selon la revendication 6, caractérisé en ce que la chambre d'extraction est une chambre verticale, et qu'une ouverture d'évacuation (30) pour la matière séparée de l'écoulement d'air est agencée dans la partie centrale du fond de la chambre d'extraction. Appareil selon la revendication 6, caractérisé en ce que la chambre d'extraction est une chambre verticale d'une hauteur comprise entre 2 et 9 mètres, de façon préférée entre 3 et 7 mètres, et d'un diamètre entre 0,5 et 3 mètres, de façon préférée entre 1 et 2 mètres.






IPC
A Täglicher Lebensbedarf
B Arbeitsverfahren; Transportieren
C Chemie; Hüttenwesen
D Textilien; Papier
E Bauwesen; Erdbohren; Bergbau
F Maschinenbau; Beleuchtung; Heizung; Waffen; Sprengen
G Physik
H Elektrotechnik

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