Submersible pump

Claim 1

A submersible pump comprising: (a) a motor section having a motor encased within a motor frame; (b) a pump section having a pump casing and a semi-open type impeller including a shroud mounted on the distal end of a motor shaft extending from said motor into said pump casing; (c) an intermediate casing fastened to said motor frame by a plurality of bolts the heads of which bear against the side of said intermediate casing opposite said motor frame, said pump casing being mounted on the side of said intermediate casing opposite said motor frame and having a hole therethrough which permits said motor shaft to extend therethrough from said motor to the interior of said pump casing; and (d) a protecting member disposed between said intermediate casing and said pump casing, said protecting member having a surface which opposes the backside of the shroud of said impeller, said protecting member being made of wear-resistant material and being sized, shaped, and positioned to surround the heads of said bolts, the surface of said shroud which opposes the backside of the shroud of said impeller being canted relative to said protecting member so that the radial outer edge of said shroud is spaced from said protecting member by a larger distance than is the radial inner edge of said shroud, said protecting member comprising: (i) a radially inner portion including the surface of said protecting member which opposes the backside of the shroud of said impeller, the surface of said protecting member which opposes the backside of the shroud being recessed to form a concave flat surface, and (ii) an annular flange which extends radially outwardly from said radially inner portion, said annular flange in turn being divided into a radially outer portion and a radially inner portion, the radially outer portion of said annular flange serving as a seal packing between said pump casing and said intermediate casing and the radially inner portion containing a plurality of holes each one of which surrounds the head of one of said bolts, said annular flange, said intermediate casing, and said pump casing being sized and shaped so that said pump casing sealingly closes said plurality of holes, preventing liquid from entering said holes during use of the submersible pump.