Presses – Plural presses – Stacked boxes or plates
Reexamination Certificate
2002-04-19
2003-09-30
Ostrager, Allen (Department: 3725)
Presses
Plural presses
Stacked boxes or plates
C100S204000, C210S230000
Reexamination Certificate
active
06626094
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to a filter press with a stack of vertically oriented or aligned, horizontally displaceable filter plates. Adjacent one of the filter plates are mutually coupled via at least one connecting element each. A respective filter chamber is defined between adjacent ones of the filter plates. The filter plates lie against one another with sealing edges in a pressing position of the stack of filter plates, and are displaceable successively to a discharge position by the horizontal displacement of at least one filter plate, in which discharge position the horizontal distance of adjacent filter plates is limited by the action of a coupling element of a filter plate on a stop surface of the connecting element of an adjacent filter plate.
BACKGROUND INFORMATION AND RELATED ART
Such a filter plate is known from DE 44 28 963 C1 for example. The connecting elements are arranged as levers which are swivelably held on laterally projecting projections of the filter plates. The levers are provided with two arms each, namely an arm with a holding hook which with respect to the opening direction is at the rear and is latched behind the projection of the next filter plate at the rear in the pressing or filtering position. Moreover, the levers comprise a front arm which is provided with a control surface which during the movement away of the next filter plate at the front, once the same has moved away over a predetermined path, produces a swiveling movement of the lever by cooperating with its projection and during which its holding hook detaches from the projection of the next filter plate at the rear. In this process the control surface encloses a recess in the hook-like front arm of the lever in which the projection of the next filter plate at the front is continually received and is provided at its base with the stop surface for fixing, i.e. limiting the plate distance in the discharge position.
The levers thus fulfill a double function by mutually locking the adjacent filter plates based on the pressing position on the one hand and thus preventing that swelling filter cake will lead to the expulsion of such filter plates which should not yet be emptied, and by acting as connecting elements on the other hand which in the discharge position of the filter plates define their maximum distance with respect to one another.
A typical aspect for the known filter press is the sequential emptying of only one filter chamber successively, with the as yet unemptied filter chambers remaining mutually locked until immediately before the discharging process. The known filter press is not suitable for discharging principles in which a section of the stack consisting of a plurality of filter plates is to be unlocked simultaneously, since the unlatching of the filter plates can always only occur successively.
From DE 43 25 055 A1 a filter press is known whose filter plates are mutually chained together by brackets and connecting links. Whereas the brackets are swivelably held on a filter plate, the connecting brackets connect one each of the brackets with an adjacent filter plate in a flexible way. A hook is each arranged on the brackets which latches into projections on the filter plates when the filter plates are pushed together into a stack. The joints between the brackets and the connecting links are disposed in such a way that when two adjacent filter plates are pulled apart the hook which is latched into the projection of the next following filter plate will detach from this projection to the amount to which the bracket which belongs to said hook with the connecting link pulling the same assumes a stretched position. It is to be prevented in this way that intermediate spaces will open prematurely between the filter plates during the opening of the filter press in which emerging filter cakes could get stuck.
If the plate stacks were opened in sections in this known filter plate it is also not ensured in this case that the discharge distance between adjacent plates in all sections would be of the same size because a relief of the sealing edges decreases continually with rising distance of the filter plate from the movable head plate prior to the pulling apart of the stack of plates after the relief, i.e. removal of the locking pressure.
SUMMARY OF THE INVENTION
The invention is based on the object of further developing a filter press in such a way that during a sequential discharge of complete sections of the stack of plates, always the same discharge distance of adjacent filter plates can be achieved during the discharge of all sections. The connecting elements should simultaneously comprise a latching function for the filter plates of the sections not yet designated for discharge and a connecting function for maintaining the discharge distance.
Based on a filter press of the kind described above, this object is achieved in accordance with the invention in such a way that the filter plates, based on the pressing position, can be displaced to a relief position by displacing a filter plate in which the sealing edges of the filter plates are detached from the associated sealing surfaces and in which the coupling elements rest on a blocking surface of the connecting elements which prevents the further horizontal spacing of adjacent filter plates, with the contact of the coupling elements on the blocking surfaces being removable by unlatching the associated connecting elements, so that a further displacement of adjacent filter plates to the discharge position is possible.
After ending the actual filtration process, the opening and discharging process occurs as follows in the press in accordance with the invention:
At first, a relief of all filter plates is achieved by the displacement of the first filter plate (as seen from the pressing plate) and subsequently all further filter plates in such a way that the connecting elements allow an only very small distance of adjacent filter plates, so that a transmission of the tensile force from one filter plate to the next occurs once its distance is merely a few millimeters. This small distance of adjacent filter plates from one another is necessary, however, in order to achieve a relief of the sealing edges of the filter plates which are under a pretension in the pressing position. In the relieved state the sealing edges typically project a few millimeters above the surface of the filter plates in order to achieve the required sealing of the filter chambers in the pressing position of the packet due to the elastic deformation. The transfer of all filter plates from the pressing position to the relief position occurs appropriately for the entire stack of plates in one job step, namely preferably by using the closing cylinder in that the same is moved back by the sum total of the individual relief distances.
The advantage of the solution in accordance with the invention is that with the help of the connecting elements in accordance with the application it is possible to produce an active relief of the sealing edges of the entire stack of plates before the plates of the first section are brought to the discharge distance. This active relief ensures that the filter plates will all have the same distance with respect to each other as defined by the connecting brackets and that in this position the sealing edges of the filter plates are completely relieved. Only in this way is it possible to prevent that during a “migration” of the discharge section from the first to the last section of the stack of plates an even discharge distance is maintained.
In apparatuses according to the state of the art the discharge distance of the sections emptied at a later time is decreased more and more in such a way that the sealing edges of the associated plates have become relieved less and less by their own power in the case of missing preceding active relief. This relief occurs in apparatuses according to the state of the art at the time at which plates are actually pulled apart to the discharge distance, as a result of which, especially when a
Fasse W. F.
Fasse W. G.
Nguyen Jimmy
Ostrager Allen
Outokumpu Oyj
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