The present invention relates to filter presses and, more particularly, to apparatus in a filter press for automatically moving filter plates to an open position toward a movable head plate so that the material retained within the filter press may be discharged.
Filter presses of the general type to which the present invention is applicable comprise a plurality of movable filter plates which are supported in horizontally stacked relation. The filter plates are held in place under pressure during operation of the filter press to provide a plurality of parallel connected filtering chambers. Materials which are supported within a liquid are retained within the chambers while filtered liquid is passed from the filter press. Such presses are useful in a wide spectrum of applications varying from sludge treatment and scrap recovery to food processing and wine making.
Due to the nature of the filtration performed by filter presses, the size and number of filter plates can be large with each of the filter plates being large and of considerable weight. Accordingly, mechanical apparatus is normally provided for moving the individual filter plates to an open position toward the movable head plate once the head plate has been retracted to permit opening and discharging of the filter press. Due to the size and potentially large number of the filter plates, the opening/discharging of the filter plates can be a time consuming operation and, hence, it is preferably performed automatically by the plate moving apparatus.
In accordance with one prior art arrangement disclosed in U.S. Pat. No. 3,251,472, filter plates are automatically moved toward the retracted movable head plate by means of reciprocating members which are mounted on screw shafts with the reciprocating members including pushers adapted to catch the filter plates by arms extending from either side thereof. The movement of the reciprocating members is controlled by electrical limit switches which are mounted upon the reciprocating members. While this arrangement provides automatic movement of the filter plates in a filter press, problems can be encountered due to the electrical connections which must be made with the switches which are mounted upon and move with the reciprocating members.
It is, therefore, apparent that the need exists for improved automatic filter plate moving apparatus for use in filter presses which provides automatic movement of the individual filter plates to an opened position yet does not require electrical interconnections to moving portions of the apparatus which interconnections can cause maintenance problems and failures.