DE3214255C2 - Device for cleaning hollow filters for powder coating systems - Google Patents

Abstract

A device housing (1) is divided by partitions (2 + 3) into a nozzle chamber (4), a filter chamber (5) and a blower chamber (7). A hollow filter (12) with a cylindrical, zigzag-folded filter element (16) is mounted on the partition (3) by means of a clamping and holding device in the filter chamber (5) so that it can be rotated and rotated by an indexing mechanism (43). A blower nozzle head (34) is moved back and forth in the jacket direction by a compressed air cylinder (46) close to the circumference of the filter element (16) by a compressed air cylinder (46). In the end positions, the indexing mechanism (43) also briefly switches on a pressure pulse nozzle (29), which is closely assembled with a compressed air tank (30) and blows through a trumpet-shaped inlet pipe (26) into the clean gas interior (20) of the hollow filter. A fan (8) sucks air from the raw gas space (32) of the filter chamber through a Nachfil ter unit (51) and emits an exhaust air mostly through the nozzle chamber (4) and inlet pipe (26) into the clean gas space (20). A first portion of the completely cleaned powder is collected in a colourfast collecting vessel (47), a further powder portion in a collecting vessel (53) below the post-filter unit (59). Instead of the pressure pulse nozzle (29), a possibly movable blowing nozzle can also be attached to the clean gas side.

Description

The invention relates to a device for cleaning of hollow filters for powder coating systems,

especially feed candles made of thin surface filter material, with a blowing nozzle directed towards the wall of the filter and an adjusting arrangement /.um Kclniivvemcllcn of the blowing nozzle and filicrwandunK. whereby the killer wall from the clean gas side door periodically is cleaned by pressure changes.

Devices of this type are known from DE-OS 27 31 123. There are cylindrical Rlterkerzen with zigzag folded cylinder jacket made of thin-walled inexpensive material such as paper, which is only used for a single color and be replaced if there is a peeling on the outside applied powder layer with a single pressure pulse device that acts from the inside is no longer possible This is entirely justified in terms of the cost of the filter material, if only Only a few shades of color need to be processed, especially since one or two filters per system are expected will.

In the newer coating lines, on the other hand, several recovery units are used one after the other used, each about ten such filter elements exhibit. In addition, some companies work with up to twenty or more colors If you only use each filter for the specific color, the only storage costs for the filter elements would be quite considerably, quite apart from the fact that the individual color tones are then contaminated can not be ruled out In addition, the opinion has emerged that for rapid color change always the entire filter units should be replaced, which in modern coating lines means the investment outlay unusually increases

It is also known per se to clean filter bags made of textile fabric by washing processes, but This cleaning process is also relatively expensive and requires the numerous required Filter elements, in turn, increased investment costs

The invention is based on the device described above and has the object of providing this device to develop in such a way that a practically complete cleaning of at least the thin-walled and inexpensive hollow filter elements made of paper or comparable material and thus the The number of filter elements to be kept available and also filter units per coating system is reduced.

To achieve this object, according to the invention, a filter chamber is provided in a separate cleaning housing with a holding and clamping device for the sealing clamping of the open end of the hollow filter provided in the area of a chamber wall, and a blow nozzle arrangement is the raw gas side of the Associated hollow filter, while the clean gas side of a separate, periodically acting pressure change device is exposed.

The set-up times for the change process are relatively short and correspond to the times that you need to change a filter in a filter unit yourself. The separate handling This benefits from the fact that the filter elements are provided with edge reinforcements or in or on dimensionally stable Straps are attached and equipped with fasteners that allow quick and convenient removal and reinsertion. The same fasteners can easily be used with the Device according to the invention are used, which is normally for the same type of filter elements is used, but also used for the use of differently designed filter elements can be

For the cleaning process itself, no separate rules are even required, since almost all of the lies always a few colors are used very frequently and a larger number of color tones are only used periodically. If necessary, you can leave the filters for the main colors permanently installed in individual filter units for the special colors only have one or two such filter units ready and then design the work plan so, that the special colors are only used after a sufficient period of time.

Therefore, the surface part of the filter element can repeatedly be subjected to a very thorough cleaning process which can be achieved with the available means with thin-walled filters While with fabric filters, fleece filters, fabric filters and the like powder particles! deep into the layer material they can penetrate the surface of the filter material made of paper, for example, practically only on the surface knock down and there are no special adhesive forces to develop. The vast majority of the powder is therefore simply swept off again by intensive blowing, and only a few of the powder particles, which have become more stubborn, then have to go through the Changes in pressure are released from the clean gas side. In this way it is therefore very possible to thoroughly and completely free the entire filter element from the previous color shade and for other color shades to use.

In contrast to washing processes and dgL, the cleaned powder can in principle be recovered be, for example, in that at the bottom of the filter chamber below the hollow filter to be cleaned a particular exchangeable collecting vessel for the detached coating powder is arranged. This so obtained Powder can then be used again for coating immediately or after a preparation process will.

According to a further inventive proposal, the Rohgt., Space of the filter chamber on the way over a in particular a filter unit provided with its own cleaning device to a vacuum source connected. The detached powder, if it does not fall into the collecting vessel, is removed from the post-filter unit collected, for example by a second collecting vessel arranged under the post-filter unit, the powder particles from the underside of the filter chamber below the first collection vessel

so can be fed through an overhead guard.

In principle, it is of course possible to completely clean all powder-carrying parts of the device when the color is changed, so that the powder collected by the secondary filter unit in the second collecting vessel can be carried out again into the coating process. However, this effort would only be justified if the degree of recovery was otherwise unusually low
The vacuum source is expediently formed by a fan, in particular a circulating air fan, which is connected on the pressure side to the clean gas space of the filter chamber.Even if the pressure outlet of the fan and the inlet of the clean gas space are only arranged adjacent in the space, most of the air volume expelled is circulated , possibly also sucked in through an upstream filter.

A pressure change device attached to the clean gas side of the filter wall is expedient.

gerweise as a jerky acting pressure pulse device formed, the individual surface elements, because of the simpler execution but also at the same time can capture entire filter wall.

Preferably, the holding and clamping device an inlet device for the compressed air supplied to the inner clean gas side of the filter is assigned, the smallest cross-section of which is several times smaller than the irine cross-section of the filter. As a result, the Air from this smallest cross section expands into the interior of the hollow filter

The holding and clamping device is advantageously inserted centrally into the edge of the filter assigned trumpet-like expanded inlet tube, which is in particular in the manner of a Venturi tube to his The inlet end is widened like a funnel

Here, a pulse nozzle of the pressure pulse device can be centered through the inlet device in be directed into the clean gas space of the filter. In this way the trumpet reed acts like a Injector, accelerating the circulating air and thus increasing the pressure. So it is the permanently maintained slight internal pressure briefly in the entire interior sharply increased, which practically affects the whole The effect of the filter wall under elastic back and forth deformation The impact effect is all the greater, the shorter the flow losses between the overpressure source and the nozzle. It is therefore advisable to use the pulse nozzle the pressure pulse device with a pulse control valve a separate compressed air tank to be assigned in close proximity.

According to a further proposal of the invention, a blower nozzle part is between the hollow filter in the longitudinal direction its end positions moving back and forth automatically attached. In this way, for example When hiking up and down, a whole circumferential line must be cleaned off. As here, however, relatively large amounts of air would have to be circulated, is currently preferred a nozzle head along a To arrange the surface line of the hollow body movable and the filter by means of a rotatably mounted washer to guide the holding and clamping device rotatably and drivably in the circumferential direction. In this way although the treatment time is narrowed, since one almost cleaned off point by point Filter element and achieves a higher degree of recovery due to the lower air turbulence.

In principle, the filter can also be rotated uniformly. However, it has been shown that the Cleaning is improved if the washer has a is assigned in particular designed as a pawl switch gear indexing device. In this In this case, the action remains constant over the entire surface line during a stroke of the bias nozzle head

The indexing mechanism for the ring disk and / or the control valve of the pulse nozzle can or can be connected to the End position control of the movement drive, which is preferably designed as a compressed air cylinder, for the blow nozzle head connect. An impulse can be placed in either or only one of the two stroke ends, as required give.

Now there is not necessarily one on the clean gas side Pressure pulse device, i.e. a jerk operated Pulse nozzle may be provided, but it can on opposite sides of the feed wall at least one nozzle part be movably guided in such a way that the paths of the two nozzle parts Maintain a sufficient distance between them, in particular at least in the lateral or circumferential direction are offset from one another. As a rule, blow nozzle heads that act on narrowly limited areas will be used, on the clean gas side it is primarily a question of the greatest possible expulsion pressure from the inside to apply to the outside, while it is on the raw gas side to sweep away the knocked down there Layer of powder particles is driving and switching can basically the inside and outside be the same regardless of where the clean gas side and the raw gas side are now.

υ For filter candles folded in a zigzag shape expediently the switching step of the indexing device to the mean distance between adjacent ones Matched filter folds This can be done, for example, if the filter candle is sufficiently dimensionally stable. always be blown into a fold in the same way.

According to a preferred embodiment of the invention, the blow nozzle head has several, in particular different aligned air nozzles, which can be arranged in rows and rows, for example, each of several adjacent folds of the hollow filter at least * one row of nozzles is assigned the cleaning process is also improved when the air nozzles on the two outer rows are aligned with the filter axis of the the nozzle head used on the raw gas side are each set at an angle to the outside, so always one The air nozzle blows diagonally forward in the direction of movement on the other hand, the nozzle jet should hit the filter wall as perpendicularly as possible.

The drawing shows an embodiment of the invention schematically.
It shows

F i g. 1 shows a longitudinal section through a cleaning device according to the invention,

F i g. 2 shows a section along the line II-II in FIG. 1,
F i g. 3 shows an enlarged partial illustration from FIG. 1 with changed height of the air nozzle head and
F i g. 4 shows a section along the line IH-I f I in FIG. 2.
The device housing I is subdivided by a vertical partition 2 and a horizontal partition 3 into a nozzle chamber 4, a filter chamber 5, a refill chamber 6 and a blower chamber 7. Its blower 8 is on the pressure side through an opening 10 provided in the chamber ceiling 9 with the original air Link. However, since the nozzle chamber 4 has a suction opening 11 on the side just above the opening 10, possibly with a prefilter, the blower air is largely sucked in as circulating air from the nozzle chamber 4 through the filter chamber 5 and the post-filter chamber 6

The hollow filter 12 to be cleaned is, as shown in FIGS. 1 and 5 can be seen through an essentially cylindrical filter candle formed whose filter element is made of fine-pored paper or the like 16 is folded in a zigzag shape, seen from the outside with wedge ribs 13 with wedge gaps 14 below about Alternate the same angular distance and are supported on the inside by a cylindrical perforated plate 15. On the lower one At the end, the edge of the filter elements 16 is surrounded by a cup-shaped sheet metal base 17 and at the top End of a pot rim 18 on an annular disk 19, which is in an opening in the partition 3 around

7 8

a vertical axis is rotatably mounted. set up box or bowl-shaped collective

To attach the hollow filter 12 to the annular disk barrel 47 caught.

19 serve the same means as with the suspension in this collecting vessel 47 can just like the Hohlfil filter units, namely an axial threaded spindle ter 12 itself by means of a door 48 lock 21 with crank 22 and nut 23 for support on s ne opening in the outer wall of the filter chamber 5 a web of the annular disk 19. This firmly carries one to be exchanged and can be used as a pure color ratchet toothed ring 24 and the edge of a trumpet powder immediately or after a processing advantage extended inlet pipe 25, the inlet side a course of reuse respectively,
A slightly conical widening 26 forms in the post-filter chamber 6 below the fan 8

At a distance above this extension 26 is a post-filter unit 49 with individual filter elements in the io Nozzle chamber 4 has a pressure pulse device as elements 51 in the form of rectangular pockets. Pressure changing device 27 attached, which brought close. The post-filter unit can be

assembled its own, for example to a compressed air device 52 in a known manner, at least to a limited extent.

Line connected pressure vessel 30 and a pneumatic.

Malically controllable pulse valve 28 with pulse nozzle 29 is at a distance below the post-filter unit 49

having. This sends out along the filter axis 31 peri- is a second box-shaped collecting vessel 53 out-

odically controlled pressure impulses by the trumpet perceptibly attached. It is turned inwards on all sides.

len-shaped inlet pipe 25 through into the interior and protrudes through guide walls of a pyramid funnel 54, the

thus the rvcingasrauiü 20 of Filicrkarnmcr 5. If primarily a front bottom of the Füterkarnner 5 sjnter-

Pressure pulse surges in the axis of the trumpet tube 20 half of the collecting vessel 47 inclined wall 55

are attached, they tear air into the edge like an injector.

range with and thereby achieve a further sudden- Deviating from the execution shown must before the pressure increase in the clean gas space 20, as a result of which the pressure exerted from the clean gas side increases the arrows 33 instantly do not apply almost the same process to the entire inner bender at the same time Overpressure on the entire filter wall 16 25 area, but you can reach small areas empty is and thereby also powder particles a "f d" r elements successively through a single, close together Be detached on the outside, the nozzle that is not attached to the wall briefly and locally Rinse the res from the same side. load even more pressure. For example,

In the raw gas space 32, as also from FIG. 3, for example, a blow nozzle head 34 on the inside or on the

hen, close to the circumference of the filter element 16, a blown 30 clean gas side of the hollow filter, with all

düset.fCopf 34 attached

vertical heads are in four vertical rows and three horizontal to the greatest possible local deformation and one

fair parts blow nozzles 35 attached so that expulsion effect should be designed out. So it is

the nozzles of the individual rows in a wedge - not necessary that about nozzles of lines 37 and 38

Blow in gap 14, d. H. the circumferential distance of the Keilrip- 3s are directed obliquely up and down, but one

pen 13 is roughly equal to the horizontal distance that can possibly use a single nozzle there, which is a

Blow nozzles 35. generated the more powerful pressure hammer when they are from

The middle line 36 blows approximately perpendicular to the filter - a wedge gap 14 changes over to the following axis 31, the upper line 37 is inclined upwards, the two blow heads can also be fixed to one another, the lower line 38 obliquely downwards. Arrange the blow nozzle and move it on parallel paths. Better ersenkopf 34 is held on a slide 39, which, however, appears to retain the sweeping traction of a shield 40 on the vertical guide rods in the longitudinal direction on the raw gas side 41 and on the piston rod 42 of a print on the On the clean gas side, on the other hand, the rotary movement of the air cylinder 46 is fastened, which is to be allowed to prevail under the control in order to reinforce the impact effect. Limit switch, not shown, between the lower 45 ken. Of course, the end position in FIG. 1 and the paths of both blower nozzle heads indicated by 341 occur, but also moved to the upper end position. According to FIG. 2 is the blower - this can be avoided in terms of control,
nozzle head 34 slightly below its upper end position- A movable blower nozzle head or a movable position. Pressure pulse nozzle can also be used in addition to the stationary

The tooth pitch of the ratchet toothed ring 24 is to be provided as 50 arranged pressure pulse nozzle, as F i g. 3 shows, based on the circumferential division at all on both sides of the filter wall mehreder V-ribs 13. It will be attached to the impulse emitted by a re cleaning nozzles Ratchet mechanism 43 with compressed air cylinder 44 and Fe- act the same or different. To an overlap latch 45 advance the paths of nozzles acting against one another by switching step a switches which prevent the angular division between the wedge 55, it may be appropriate, for example, a ribs 13 corresponds to a jerk-like nozzle on the inside in!, longitudinal direction of the

The commands for the pulse nozzle 29 and the filter between two external sweeping nozzles Pneumatic cylinders 44 are simultaneously installed in one or, with the inner nozzle in addition one

overloaded both end positions of the compressed air cylinder 46 with its increased rotational movement about the filter axis.

Reversal triggered So that every KeUspalt 14 60 is turned off. If you then have all three groups of air nozzles

moves at least twice in the upward direction and twice over the entire length of the filter, results

in the downward direction through the four rows of blower nozzles 35 avoiding overlapping a special

rinsed with even and intensive cleaning during the switchover.

A pressure pulse pulse is triggered in the other wedge gap.

wsrd and the 65 gene that is not only lifted off by blowing is the cleaning of cylindrical, prismatic

Powder particles blown off or star-shaped hollow filters possible, on whose internal A significant proportion of the paint powder side detached in this way is deposited on the coating powder

vers is in a first, below the hollow filter 12. The filters themselves do not necessarily have to be attached to one

In the end it will be complete, but it is best to do this Completion of the cleaning process after removing it from the filter unit to produce the precipitate to prevent individual particles on the clean gas side.

For this purpose 3 sheets of drawings

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Claims (21)

Patent claims: 1. Device for cleaning hollow filters for powder coating systems, especially candle holders made of thin surface filter material, with a blowing nozzle directed towards the wall of the filter and an adjustment arrangement for relative adjustment of air nozzle and feed wall, the filter wall periodically from the clean gas side is cleaned by pressure changes, characterized in that in a separate Cleaning housing (1) a filter chamber (5) with a holding and clamping device (19, 21-23) for the sealing clamping of the or an open end of the hollow filter (12) in the area a chamber wall (3) and a blow nozzle arrangement (34) on the raw gas side of the hollow filter (12) zugeonijSt is, while the clean gas side (20) a separate, periodically acting pressure change device (27) is exposed 2. Device according to claim 1, characterized in that that at the bottom of the filter chamber (5) below the hollow filter (12) to be cleaned a particular exchangeable collecting vessel (47) for the detached coating powder is arranged 3. Device according to claim 2, characterized in that that the raw gas space (32) of the filter chamber on the way over one in particular with its own Abreinigu ?? 5vorrichuing (52) provided post-filter unit (49) is connected to a vacuum source (8) 4. Apparatus according to claim 3, characterized in that under the Nachfiltt, a unit (49) second collecting vessel (53) for coating powder to be collected there is arranged 5. Apparatus according to claim 4, characterized by one of the underside of the filter chamber (5) transfer element guided below the first collecting vessel (47) to over the second collecting vessel (53) 6. Apparatus according to claim 5, characterized in that the negative pressure source by a fan (8), in particular a circulating air fan is formed, which on the pressure side with the clean gas space (20) of the filter chamber (5) communicates 7. Apparatus according to claim 1 or 6, characterized in that the holding and clamping device (19,21-23) an inlet device for the inner clean gas side of the filter (12) fed Air is assigned whose smallest cross section is several times smaller than the internal cross section of the filter (12). 8. Apparatus according to claim 7, characterized in that the holding and clamping device (19) an inlet pipe (25) which is widened in the shape of a trumpet in the center of the edge of the hollow filter (12) assigned 9. Apparatus according to claim 8, characterized in that the inlet pipe (25) in the manner of an eo Venturi tube towards its inlet end a trichler-like Has extension (26) 10. Device according to one of claims 1 to 9, characterized in that a pressure changing device attached to the clean gas side (20) of the feed wall (16) is designed as an impact-like pressure pulse device (27). 11. The device according to claim 10, characterized in that that a pulse nozzle (29) of the pressure pulse device centrically through the inlet device is directed through into the clean gas space (20) of the filter (12) 12. Apparatus according to claim 1 or 11, characterized characterized in that the pulse nozzle (29) of the Druckimpulsvo.Tichtung (27) with a pulse control valve (28) a separate compressed air tank (3fc) narrow is assigned adjacent 13. Device according to one of claims 1 to 12, characterized in that at least one Blowing nozzle part reciprocating in the longitudinal direction of the hollow filter (12) between its end positions is attached automatically movable 14. The apparatus according to claim 13, characterized in that a blow nozzle head (34) along a The surface line of the hollow filter (12) is movably arranged and the filter is rotatably mounted by means of a Ring disk (19) of the holding and clamping device (iS, 21-23) rotatable in the circumferential direction and is driven 15. The device according to claim 13, characterized in that the annular disc (19) is one in particular is assigned as a pawl switching mechanism (43) designed indexing device 16. Apparatus according to claim 12 or 13, characterized in that the indexing mechanism (43) for the annular disc (19) and / or the control valve (28) of the pulse nozzle (29) to the end position control of the preferably designed as a compressed air cylinder (46) Movement drive for the blow nozzle head (34) is or are connected. 17. Device according to one of claims 13 to 16, characterized in that on opposite sides of the filter wall (16) in each case at least a nozzle part (34) is movably guided in such a way that the paths of the two nozzle parts are sufficient Keep a distance from each other, especially are offset from one another at least in the jacket or circumferential direction. 18. The apparatus of claim 16 or 17, for in Hollow filter (12) folded in a zigzag shape in the circumferential direction, characterized in that the switching step the indexing device (43) to the mean distance between adjacent filter folds (13, 14) is coordinated 19. Device according to one of claims 14 to 18, characterized in that the nozzle head (34) has several, in particular differently oriented Has blowing nozzles (35) 20. The device according to claim 19, characterized in that the blow nozzles (35) in series and Lines are ordered and each fold (13, 14) of the hollow filter (12) is assigned at least one row of nozzles is 21. The device according to claim 20, characterized in that the blow nozzles (35) of the two outer Rows of the nozzle head (34) used on the raw gas side to the filter axis (31) in each case are employed at an angle to the outside.