Belt filter medium

A belt filter medium for use with a filter apparatus for pressure filtering fluid slurry materials containing liquid and solid materials in a filter chamber and for creating a substantially dry filter cake of said solid materials, said apparatus having mechanical means for opening and closing said filter chamber and for maintaining said chamber closed and under pressure during filtering operations and for opening said chamber after filtering has been completed, belt drive means for positioning said belt filter medium within said filter chamber when said chamber is opened and pressure sealed within said chamber when said chamber is closed, said belt drive means including sensing means positioned with respect to said filter chamber for sensing the position of said belt filter medium with respect to said upper and lower plate members and for controlling operation of said belt drive means, said belt filter medium characterized by:

• a continuous belt,
• said continuous belt filter medium including a plurality of detectable marking means along the length of said belt, said plurality of marking means being separated by a distance larger than the largest lateral dimension of said filter chamber, and said marking means being adapted to cooperate with sensing means of said belt drive means for controlling operation of said belt drive means to position said detectable marking means and for controlling operation of said belt drive means.