Sifter frame for powder particle sifter

A sifter frame for a powder particle sifter comprising:

• a pair of frame elements including an outer frame and an inner frame, the outer frame being formed to have an outer block of a rectangular four-sided shape by the combination of outer block frame members each having the same height and a receiving plate to include in the inner side of the outer block each of a pair of fine powder dropping ports opened in an upward/downward direction along both inner sides of a pair of the confronting sides of the rectangular four sides, a rough powder dropping port opened in an upward/downward direction along the inner side of one of the other pair of the confronting sides, outer block frame members constituting sides opposite to the other pair of the confronting sides, a rectangular fine powder receiving plate horizontally disposed at a position of intermediate height in the region surrounded by the rough powder dropping port and the fine powder dropping ports, and an inner frame fitting portion above the receiving plate and the rough powder dropping port;
• and
• the inner frame being formed to a rectangular shape to be fitted with the inner frame fitting portion formed to said outer frame without producing substantially any gap therebetween and including each of a rectangular sifter net portion having a sifter net stretched over the ceiling surface of the inner frame to sift fine powder from rough powder and drop the sifted fine powder onto the receiving plate and a rough powder dropping port formed to a shape in coincidence with that of the rough powder dropping port of the outer frame along a side of the sifter net portion, wherein:
• when a plurality of sifter frames each assembled by fitting said inner frame with the inner frame fitting portion of said outer frame are stacked in multi-stages so that the positions of said rough powder dropping ports are alternately disposed, a closed annular seal surface formed to said outer frame is air-tightly engaged with the closed annular seal surface formed by the inner frame and the outer frame of said sifter frame stacked to the lower stage to thereby seal the rough powder region and the fine powder region of each sifter net.

A sifter frame for a powder particle sifter comprising:

• a pair of frame elements inducting a lower frame and an upper frame, the lower frame being formed to have an outer block of a rectangular four-sided shape by the combination of outer block frame members each having the same height and a receiving plate to include in the inner side of the outer block each of a pair of fine powder dropping ports opened in an upward/downward direction along both inner sides of a pair of the confronting sides of the rectangular four sides, a rough powder dropping port opened in an upward/downward direction along the inner side of one of the other pair of the confronting sides, outer block frame members constituting sides opposite to the other pair of the confronting sides, a rectangular fine powder receiving plate horizontally disposed at a position of intermediate height in the region surrounded by the rough powder dropping port and the fine powder dropping ports, and an inner frame fitting portion above the receiving plate and the rough powder dropping port;
• and
• the upper frame including each of a rectangular sifter net portion having a sifter net stretched over the ceiling surface of a region confronting the upper portion of the receiving plate of the lower frame to sift fine powder from rough powder, a pair of fine powder dropping ports and a rough powder dropping port disposed so that the positions and the shapes thereof coincide with those of a pair of the fine powder dropping ports and the rough powder dropping port of the lower frame, with the outside shape of the upper frame being formed to coincide with that of the lower frame by the combination of frame members and the sifter net, wherein:
• when a plurality of sifter frames each assembled by combining said lower frame and said upper frame are stacked in multi-stages so that the positions of said rough powder dropping ports are alternately disposed, a closed annular seal surface formed to said lower surface of said lower frame is air-tightly engaged with the upper surface of said sifter frame stacked to the lower stage to thereby seal the rough powder region and the fine powder region of each sifter frame.