Filter plate subframe
A filter plate subframe for a filter plate frame assembly having a filter plate frame and a filter plate subframe slidably receivable therein. The subframe comprises separate periphery segments attached to each other so as to form a continuous, generally rectangular periphery region with flank sides and end sides. The flank sides have a linear density lower than that of the end sides, and the end sides have a bending stiffness higher than that of the end flank, while either or both of the first end side and the second end side are provided with a reinforcement bar for increasing the bending stiffness said end sides. A supporting surface is provided on a first planar side of periphery segments forming the flank sides the supporting surface.
1. A filter plate subframe for a filter plate frame assembly having a filter plate frame and a filter plate subframe receivable therein,
wherein the subframe comprises separate periphery segments attached to each other so as to form a continuous periphery region of the subframe, such that the periphery region surrounds and delimits an open region of the subframe,
wherein the periphery region is of a generally rectangular shape having:
a first flank side and an opposite second flank side parallel with the first flank side, the flank sides running along a longitudinal direction of the subframe, and
a first end side and an opposite second end side parallel with the first end side, the end sides being transverse to the flank sides,
wherein the flank sides have a linear density lower than that of the end sides, and the end sides have a bending stiffness higher than that of the flank sides,
wherein either or both of the first end side and the second end side are provided with a reinforcement bar for increasing the bending stiffness said end sides,
wherein the subframe is configured to be slidably receivable within a filter plate frame along the longitudinal direction of the subframe, and
wherein a supporting surface is provided on a first planar side of periphery segments forming the flank sides the supporting surface being configured to support the filter plate subframe on a corresponding receiving surface of an associated filter plate frame.
2. The filter plate subframe according to claim 1 , wherein the supporting surfaces are arranged to have a dry kinetic friction coefficient with steel of no more than 0.3, as defined in accordance with ASTM D1894.
3. The filter plate subframe according to claim 1 , wherein the reinforcement bar extends up to, or over, corners between an end side and flank sides adjacent to the end side associated to the reinforcement bar.
4. The filter plate subframe according to claim 1 , wherein the reinforcement bar is of a different material than the periphery segments, the material of the reinforcement bar having an elastic modulus higher than that of the periphery segments.
5. The filter plate subframe according to claim 4 , wherein the reinforcement bar is made from steel or a composite material, and wherein the periphery segments are made from a plastics material.
6. The filter plate subframe according to claim 1 , wherein each corner between adjacent end sides and flank sides is provided with an identical corner periphery segment.
7. The filter plate subframe according to claim 1 , wherein at least one of the periphery segments is a feed segment comprising one or more feed openings for feeding slurry to be filtered into the open region, when in use, and
wherein the feed segment is removably attached to adjacent periphery segments.
8. The filter plate subframe according to claim 7 , wherein the feed segment is removable from adjacent periphery segments in a direction away from the open region.
9. The filter plate subframe according to claim 7 , wherein the feed segment is provided at either or both of the first flank side and the second flank side.
10. The filter plate subframe according to claim 7 , wherein identical feed segments are provided at both the first flank side and the second flank side.
11. The filter plate subframe according to claim 1 , wherein a diaphragm groove being provided on a second planar side of the periphery region, opposite to the first planar side, for receiving and attaching with a corresponding bead of a filter diaphragm,
wherein the diaphragm groove runs along the periphery region and is formed on separate periphery segments attached to each other so as to form a continuous annular groove.
12. The filter plate subframe according to claim 1 , wherein a sealing strip groove being provided on the first planar side of the periphery region, for receiving and attaching with a corresponding sealing strip of a filter plate,
wherein the sealing strip groove runs along the periphery region and is formed on separate periphery segments attached to each other so as to form a continuous annular groove.
13. The filter plate subframe according to claim 1 , wherein a segment seal is provided in a joint between adjacent periphery segments.
14. The filter plate subframe according to claim 11 , wherein the segment seal is provided at a portion of the joint coinciding with the diaphragm groove and the sealing strip groove, the segment seal being provided as a cylindrical peg extending between a bottom of the diaphragm.