Liquid purification or separation – Structural installation – Flume stream type
Reexamination Certificate
2000-05-18
2001-06-12
Lithgow, Thomas M. (Department: 1724)
Liquid purification or separation
Structural installation
Flume stream type
C210S155000, C210S159000, C210S162000
Reexamination Certificate
active
06245225
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a staged filter apparatus for mechanically separating solids from liquids flowing in channels, gutters or conduits, which has a multiplicity of stage screen bars connected to form a stationary grating, and a multiplicity of stage screen bars connected to form a movable grating, the gratings being arranged inclined in the direction of flow inside the flowing liquid starting from a level situated below the surface, and the stage screen bars being constructed in a stepped fashion in the direction facing the incoming flow, and in which the movable grating can be actuated by means of a drive device on a track which, starting from a zero position which is identical in the vertical and horizontal directions to the stationary grating, permits a stroke movement which rises over the stages of the stage screen bars connected to form the stationary grating and against the direction facing the incoming flow, and which reaches at least to a position identical in the vertical direction and in the horizontal direction to the next higher stage of the stationary grating, and subsequently guides the stage screen bars of the movable grating below the stationary grating back into the zero position, the stationary grating being surrounded at least laterally by frame parts.
PRIOR ART
Such apparatuses are known as stage screens and serve the purpose inside sewage or separation plants of removing solids present in sewage.
EP 0 098 820 has disclosed a stage filter in which the drive device is present on the top side of the gratings, the movement of the movable grating being transmitted via an eccentric wheel and a support device which is connected to said eccentric wheel and embraces the stationary grating from above and outside.
The customary designs of such devices have the disadvantage that a relatively large overall height is provided in each case. Given a relatively large stroke of such screens, which reaches over a plurality of stages, the drive elements are fitted far above the gratings so that sufficient headroom is still available for the passage even of relatively large solid bodies between the drive element and the moving gratings. However, such a construction also entails corresponding dimensioning of the channel cross-sections and the intakes, which in turn substantially increases the outlay and the costs for setting up the intake structures for, for example, sewage plants.
DE 40 01 859 C2 has disclosed a filter screen for removing solid constituents from flowing liquids, in which there is arranged below the grating bars a crank drive which controls the movement of the movable grating bars. The selected lever arrangement is supported in this case on skids which are mounted in guide sections of the supporting structure.
WO 94/24373 has disclosed a staged filter screen in which the movable grating is connected eccentrically on the top side to a wheel, there being connected to said wheel, likewise eccentrically, a long thin rod which, in turn, is mounted on the frame at the other end region via chains, and thereby transmits a type of elliptical rotary movement onto the movable grating in this region. Since an essentially circular movement of the individual stages proceeds in the region of the upper eccentric connection of the movable grating and an elliptical movement proceeds in the lower region, the course of the stage screen bars in the longitudinal direction necessitates different section designs in order to ensure reliable removal. Furthermore, the chain bearing of the connecting rod is not optimum in the lower region as regards permanently reliable functioning.
SUMMARY OF THE INVENTION
Proceeding from said prior art, the invention is based on the object or the technical problem of proposing a stage screen in which the space requirement necessary for reliable operation is minimized and, at the same time, the passage of even relatively large solid bodies is rendered possible without any problem in conjunction with an arbitrarily steep inclination in the direction of flow. In this case, the construction is intended to be of simple, robust and low-maintenance design.
The staged filter apparatus according to the invention is given by the features of the independent claim
1
. Advantageous refinements and developments are covered by the dependent claims.
The device according to the invention for mechanically separating solids from liquids is therefore distinguished in that all the drive elements of the movable grating are essentially arranged in the common plane formed by the stationary grating and the movable grating in the zero position.
The result of such a construction of the apparatus is a modular design in which the entire apparatus including the drive can be installed and operated as components which are immediately ready to function inside channel cross-sections which are bounded only by the simplest lateral structures or lateral holding constructions, without the need to set up complicated structures or gutter guides, machine boxes or housings, controls or gear internals or devices for accessory parts.
The modular design likewise permits easy installation in already existing systems, for example when wear in the old plant necessitates replacement of the screen devices, and is therefore eminently suitable for adapting gutter cleaning systems to sewage fractions which have changed in the course of recent decades, for example, but also to new statutory regulations regarding the further disposal of the treated waters.
Moreover, owing to the arrangement of the drive elements of the movable grating essentially in the common plane formed by the stationary grating and the movable grating in the zero position, it is possible to realize any desired angular positions of the apparatus, so that it is possible to provide a withdrawal stroke adapted more or less steeply to the expected size of the solid fraction. Since all the drive elements are accommodated inside the module, sufficient space to pass remains as headroom above the screen bars despite a serious reduction in installation space and outlay on construction.
It is advantageous for the drive elements to include driven wheels mounted in a frame of the stationary grating, the movable grating being pivoted at the wheels in an eccentric fashion and radially relative to the wheel axle.
Such a construction permits minimization and the encapsulation and integration of the drive elements inside supporting, in particular hollow frame parts, with the result that such drive elements can also be arranged below the water level and only rotary bushings which are easy to seal need be provided.
A virtually maintenance-free design can be achieved by virtue of the fact that the drive elements include driven lateral cheeks mounted in a frame of the stationary grating, the movable grating being pivoted in an eccentric fashion at the cheeks at a point spaced apart from the bearing. Such a drive can be produced in a very simple way and requires to be monitored only visually. The work of repair and/or replacement can be carried out in a simple way.
In a further advantageous design, the drive is performed via chain drives or cardan shafts acting on the wheels/cheek(s) . Such a construction lends support to the compact design and permits large forces to be reliably transmitted, as a result of which it is also possible to manage bulky and heavy removals without any problem.
A further design measure, which is effective with a view to a compact modular design and is advantageous in the apparatus consists in that at its outermost positions, the movement track from the zero position to the higher stage and back leaves the plane defined by the stationary grating by no more than double the stage height. The required moving members and moving guides can then be designed in cooperation with the chain drives or cardan shafts already mentioned to be of relatively small construction.
Further embodiments and advantages of the invention follow from the features further set forth in the claims, as well as from the exemplary embo
Egner Umwelttechnologie GmbH
Kasper Horst M.
Lithgow Thomas M.
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