Presses – Automatic or material triggered control – Of material addition – deposition – or discharging
Reexamination Certificate
1995-07-28
2001-05-29
Gerrity, Stephen F. (Department: 3721)
Presses
Automatic or material triggered control
Of material addition, deposition, or discharging
C015S340100, C100S090000, C100S100000, C100S192000, C100S215000, C100S250000
Reexamination Certificate
active
06237480
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a method for the dustfree discharge of fine dusts from a dust collector of a cleaning vehicle, in particular a dry sweeping machine, in which the fine dusts collected in the dust collector are removed therefrom by means of a conveyor device, subsequently compacted under the action of mechanical compression, and discharged in the form of compacted cylindrical chunks or pellets. The invention further relates to an apparatus for carrying out the method.
BACKGROUND OF THE INVENTION
Such methods and likewise the associated apparatus for carrying out the method are known in particular from dry sweeping machines, in which the sweepings, and in particular the portion of fine dusts in the sweepings are not absorbed by water during the sweeping. Instead, the fine dust is separated in the dust collector on filter elements, after the coarse sweepings have previously settled, under the action of gravity and with the cooperation of an impingement hood, in the receptacle for coarse sweepings.
The problem underlying the present invention consists in that the fine dusts accumulated in the dust collector of a dry sweeping machine are liable to penetrate the lungs due their particle size and, possibly, contain health damaging substances, and that they cannot be easily added in untreated form to the receptacle for coarse sweepings. Moreover, because of the suction air current within the receptacle for coarse sweepings, it is problematic to return the fine dusts in the form of dust to the receptacle for coarse sweepings. This would lead to an endless maintenance or concentration of the dust circulation.
The present invention is based on the further development of the method described in DE 4 94 211 and the apparatus disclosed therein for a gastight discharge of the dust separated in the collection chamber of gas-cleaning installations by its removal therefrom. The further development of this known method from the year 1930 has become necessary due to the fact that the compressing of the dust into an open pipe does not permit a continuous process and, thus, is unsuitable for cleaning the dust filter of a dry sweeping machine, as is described below in more detail with reference to FIG.
1
.
Shown in
FIG. 1
is a compression tube
8
with a plug
18
(dust in compressed form) and with a compression chamber
12
filled with dust. Assuming a hydrostatic state of stress and a Coulomb state of friction on the tube wall, the mathematical model for the compacted mass being formed results in an exponential increase of pressure in direction toward a piston ram
17
with an exponent of 4 &mgr;l : D, where &mgr; is the coefficient of friction,
1
the length of the compression tube or the compression chamber, and D the diameter of the compression tube. In a continuous compacting process with an alternating piston ram
17
, a new compact is produced in compression chamber
12
, the plug
18
is pushed up, and the compact is moved to this position. This means that the plug
18
is brought from the state of static friction to the state of sliding friction. Since the coefficient of static friction is always greater than the coefficient of sliding friction, the compacted mass is further compressed during each stroke of the piston ram due the exponential increase in pressure. After few strokes of piston ram
17
, this results in that the plug
18
is no longer pushed out. A conceivable shortening of the length
1
of plug
18
itself would result in that the gas contained in the fluidized bed of dust diffuses into the plug
18
, destroys the compressed structure and, thus, allows the compacts to become softer and softer. Thus, the known method as well as the known apparatus are unsuitable for a continuous operation.
BACKGROUND AND SUMMARY OF THE INVENTION
It is therefore the object of the present invention to describe a method and an apparatus for the dustfree discharge of fine dusts from a dust collector of a cleaning vehicle of above-described kind, which permit the fine dusts to be returned into the receptacle for coarse sweepings.
In addition to the above-described characteristics of the known method, the method of the present invention provides that the counteracting force necessary to compact the fine dusts is applied in counterpressure-controlled manner substantially at the discharge end. To this end, the apparatus for carrying out the method in accordance with the present invention is provided with a compression device, which consists of a compression tube with a compression chamber, a blocking chamber, and a controlled shutoff flap closing the compression tube at its discharge end.
In accordance with the invention, the solution to eliminating the deficiencies of the known method and of the known apparatus consists in the cooperation of the tube friction and shutoff flap. In comparison with the compacted mass that forms in the compression chamber, the blocking plug becomes much smaller. The shutoff flap is kept closed for generating the counterpressure, until the desired compaction is reached. Then, the shutoff flap is opened as a result of the pressure, under which the piston ram is operated in the compacting phase, thereby reducing the resistance to ejection and permitting a movement of the compacted mass. The pressure control of the flap by the pressure of the piston ram of the compression device allows the formation of continuously compacted cylindrical chunks in any desired degree of compaction. Thus, the fine dusts are brought, under the action of mechanical compression, from their air-laden, fluidized-bed-type state to a dust-binding state of a solid mass, so as to be discharged as compacted cylindrical chunks or pellets.
More specifically, the advantages of the solution achieved by the present invention consist in that the fine dusts are present in a considerably reduced volume as a result of being compacted in dust-binding form to cylindrical chunks or pellets. From this, two alternate possibilities of further processing the pelletized or cylindrically compacted fine dusts result. First, it is possible to collect same, separately from the coarse sweepings, in their own smaller container. In this kind of further treatment, the solution of the present invention proves to be advantageous, since the consolidated fine dusts are collected at a substantially reduced volume, and that they accumulate only at this reduced volume. This brings enormous savings for communities or the operators of the cleaning vehicles, since a manual removal of dust is problematic. Second, the pelletized or cylindrically compacted fine dusts can again be mixed with the coarse sweepings. Finally, only as a result of the solution of the present invention, is it actually possible to return in a practical and continuous manner the fine dusts to the receptacle for coarse sweepings. In the known methods and apparatus, the aforesaid concentration of the dust circulation leads in many corners and niches to a “growth” of the fine dusts, which is highly undesirable. This concentration is prevented by the pelletized or cylindrically compacted fine dusts, since same are thus present in a bound, solid form. Furthermore, a continuous feed of dust from the dust bunker of the filter into the receptacle for coarse sweepings would be feasible only via bucket-wheel-type gates or other vacuum-resistant conveying devices, which would be accompanied by increased construction cost and expenditure.
For a further development of the compression device it is provided that same includes a piston-cylinder unit, the piston of which extends into a compression tube for displacement in axial direction, that the compression tube can be filled in a retracted position of the piston, and that the fine dusts are compacted by the forward movement of the piston in the blocking chamber under a simultaneous counterpressure exerted by the controlled shutoff flap. The result of the compression changes exponentially to the length of the compression tube and to the static friction, and inversely proportionally to the
Alston & Bird LLP
Gerrity Stephen F.
HET HALLER Entwicklungs- und Technologiegesellschaft mbH & Co
LandOfFree
Apparatus for the dustfree discharge of fine dust from a... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Apparatus for the dustfree discharge of fine dust from a..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Apparatus for the dustfree discharge of fine dust from a... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2506898