DUST SEPARATOR WITH CLEAN BLOWING DEVICE FOR FILTER OR FILTERS

The present invention relates to a dust separator, preferably intended for cleaning air from dust during rock drilling and the like activity, and comprising a cyclone, which supports at least one fan, by means of which dust-mixed air is sucked into the cyclone through at least one suction opening and is brought to pass one or more shell-shaped filters before the cleaned air is blown out through at least one exhaust opening, the cyclone being divided into an upper room and a lower room by a partition wall, in which the respective filter is arranged, projecting down into the lower room, at least one clean blowing device being arranged to blow compressed air from behind through the respective filter when this has become clogged by dust.

Prior Art

A dust separator of the kind mentioned above is known by the European patent specification 0841095, in which a dust separator is disclosed, which is intended to be used, e.g., in a box for handling radioactive material in the manufacture of fuel pellets for nuclear reactors The dust separator is intended to be connected to a freestanding extraction device, such as, e.g., a freestanding fan, and has devices for clean blowing the filters that are included in the dust separator. The dust separator comprises a cyclone, which has an upper room and a lower room separated by a partition wall. A number of filters are arranged hanging in the partition wall and lowered in the lower room. The upper room has a lid, in which a clean blowing nozzle for each filter is arranged. Thereby, the construction gets a relatively great building height and entails difficulties if it is desired to build it together with an extraction fan

Summary of the Invention

The object of the present invention is to provide a more compact dust separator and which also comprises a fan. Thus, the invention comprises a dust separator, comprising a cyclone, which supports at least one

fan, by means of which dust-mixed air is sucked into the cyclone through at least one suction opening and is brought to pass one or more shell-shaped filters before the cleaned air is blown out through at least one exhaust opening, the cyclone being divided into an upper room and a lower room by a par- tition wall, in which the respective filter is arranged, projecting down into the lower room, at least one clean blowing device being arranged to blow compressed air from behind through the respective filter when this has become clogged by dust The filters are covered by at least one lid, which has at least one opening for the respective filter, in which at least one valve device for cleaned air is arranged. Said at least one lid supports at least one clean blowing nozzle, which mouths on the underside of the lid The clean blowing nozzle stands in communication with at least one source of compressed air via at least one pilot valve

The respective valve device may comprise a valve disc, which via a bar stands in communication with a power-generating device, which is arranged projecting down in the respective filter of the lower room The power-generating device may consist of a compressed-air cylinder Said at least one suction opening may stand in communication with at least one outlet expander arranged in the lower room. At least one safety wall, open at the bottom, may be arranged in such a way that it surrounds the filters and said at least one outlet expander may be arranged between the safety wall and the jacket of the cyclone

Said at least one fan may consist of a centrifugal blower having a vertical rotation axis and the fan may be contained in a fan housing, which is arranged to cover an upper opening of the upper room of the cyclone and the fan housing may have at least one suction opening, which stands in communication with the upper room, and said at least one exhaust opening. The filters may be covered by a lid for one or more filters Preferably, the respective filter is covered by a lid, the lid having an opening, in which a valve device for cleaned air is arranged. The lid furthermore supports a clean blowing nozzle, which mouths on the underside of the lid and stands in communication with a source of compressed air via a pilot valve.

The compressed-air cylinder may be controlled by a pilot valve, by means of which the valve disc can be opened or closed. When the valve disc is open, air is sucked through the filter in question and is cleaned from dust By arranging the compressed-air cylinder projecting down in the filter, a smaller building height of the dust separator is obtained in comparison with similar known dust separators

The suction opening may be arranged so that the air flows in tan- gentially into the cyclone and stands in communication with an outlet expander arranged in the lower room At least one safety wall, open at the bottom, may advantageously be arranged so that it surrounds the filters and protects them from being worn by the dust of the air current The outlet expander is in this case arranged between the safety wall and the jacket of the cyclone

The fan housing may be arranged to cover an upper opening of the upper room of the cyclone and the same upper opening may essentially correspond to the cross-section of the cyclone and enable that the subjacent valve device and the filters easily are accessible when the fan housing is lifted off the cyclone. The fan housing has in this case a suction opening, which stands in communication with the upper room, and an exhaust opening at the edge thereof

List of Drawings

Figure 1 shows, in a side view partly sectioned along the line l-l in figure 2, a dust separator according to the invention Figure 2 shows, in a top view sectioned along the line H-Il in figure 1 , the dust separator according to figure 1.

Description of Embodiments

The dust separator, which is shown in the figures, comprises a cyclone 1 , which has an upper, essentially cylindrical part 1.1 and a lower essentially cone-shaped part 1 2, which in turn has a lower opening 1.3. Furthermore, the cyclone 1 has a horizontal partition wall 1 4, arranged

somewhat lowered in the essentially cylindrical part 1.1 , whereby an upper room 1.5 and a lower room 1 6 are formed in the cyclone 1

Two cone-shaped filters 2 are arranged in each an opening of the partition wall 1 4 and are held therein by means of each a lid 3 The respective lid 3 has in turn an opening 3.1 , which can be closed or opened by means of a valve disc 3.2, which via a bar 3.3 stands in communication with a compressed-air cylinder 3 4, which is arranged lowered in the respective filter 2 In figure 1 , the left valve disc 3.2 is shown in a closed state and the right valve disc 3 2 in an open state. The left valve disc 3 2 is also shown by dashed lines in an open state and the right valve disc 3.2 is also shown by dashed lines in a closed state

The essentially cylindrical part 1 1 of the cyclone 1 has a border 1.7 running around the upper room 1.5, which border supports a centrifugal blower 5, which is contained in a fan housing 5 1 The fan 5 is driven by a hydraulic motor 5 2, the drive shaft of which extends vertically down into the fan housing 5 1 The fan 5 is connected with a suction opening 5 3 of the fan housing 5 1

The respective lid 3 of the respective filter 2 supports a clean blowing nozzle 6, which via a pipe 6.1 is connected to a compressed-air system, which, e.g , may be included in a machine on which the dust separator is mounted. Clean blowing pulses of compressed air through the nozzle 6 are controlled by means of a valve 6 2 of the pipe 6 1 to the nozzle 6.

During operation, air is sucked into the dust separator through an inlet pipe 7, which extends tangentially into the upper part of the lower room 1.6 and mouths through an outlet expander 7 1 , in which the air speed is reduced in a controlled way, which gives the dust separator a higher power, which consumes less energy than what is the case in dust separators having conventional cyclones. Heavier dust, which accompanies the sucked-in, dust- mixed air, falls down through the lower opening 1.3 of the cyclone, while lighter dust is sucked further through the filters 2 and get caught on the outside of the same The cleaned air is sucked further up through the opening 3.1 of the respective lid 3, which also supports the filter 2, and is blown out

from the fan 5 through a peripherally arranged opening 5.4 of the fan housing 5.1.

The filters 2 may be protected against mechanical wear from the incoming dust by being surrounded by a preferably essentially cylindrical protection wall 8, which is shown by dashed lines in figure 1 , or separate protection walls for the respective filters 2. In this case, the outlet expander 7.1 is arranged between the protection wall 8 and the jacket 1.1 of the cyclone 1.

During full operation, the valve discs 3.2 are held in a raised position from the openings 3.1 of the filters 2 by means of the air cylinders 3.4. Upon cleaning the filters 2 during operation, one of the openings 3.1 is closed, the left one in figure 1 , by means of the appurtenant air cylinder 3.4, after which air pressure shocks are emitted from the appurtenant clean blowing nozzle 6 by means of the valve 6.2 of the clean blowing pipe 6.1. When this filter 2 is clean blown from dust, the opening 3.1 in question of the filter 2 is opened, after which the opening 3.1 of the second filter 2 is closed and clean blowing is carried out in the same way as in the first filter 2. Upon cleaning the filters 2 when the dust separator is not in operation, both the openings 3.1 are closed, after which the same clean blowing procedure takes place. The released dust falls down through the lower opening 1.3 of the cyclone 1.

Replacement of the filters 2 is carried out by the fan housing being lifted off the cyclone 1 , after which the lids 3 are loosened and are lifted up from the partition wall 1.4 of the cyclone 1. After that, the filters 2 are lifted up from the openings of the partition wall 1.4 and are replaced by new filters 2. The pipes 6.1 of the clean blowing nozzles 6 may advantageously consist of bendable hoses, whereby these do not need to be loosened from the clean blowing nozzles 6 upon exchange of the filters 2 but can be bent up from the partition wall 1.4. The invention is not limited to the embodiments shown here but may be varied within the scope of the subsequent claims.