Impeller for circumferential current pump and method of forming the same

An impeller for a circumferential current pump which is provided with a plurality of vane grooves in an outer peripheral side of a synthetic resin disc-like member rotated by a motor and is rotatably received within a substantially disc-like space formed between a pump casing and a pump cover, wherein a recess portion having a predetermined radius around a center of rotation is formed on at least one of one side surface opposing to said pump casing of said disc-like member and another side surface opposing to said pump cover, and a plurality of grooves each extending in a radial direction are radially formed within the recess portion.

A method of forming an impeller for a circumferential current pump in which a plurality of vane grooves are formed in an outer peripheral side of a synthetic resin disc-like member and a recess portion having a predetermined radius around a center of rotation is formed on at least one of one side surface of the disc-like member and another side surface thereof, wherein a ring gate for an injection molding is arranged at a position corresponding to said recess portion and a synthetic resin is injected into a cavity from the ring gate.

An impeller for a circumferential current pump which is provided with a plurality of vane grooves in an outer peripheral side of a synthetic resin disc-like member rotated by a motor and is rotatably received within a substantially disc-like space formed between a pump casing and a pump cover, wherein a recess portion having a predetermined radius around a center of rotation is formed on at least one of one side surface opposing to said pump casing of said disc-like member and another side surface opposing to said pump cover,

• wherein a ratio (L/2t) between the sum (t1+t2=2t) of a gap (t1) between said one side surface and said pump casing and a gap (t2) between said another side surface and said pump cover, and a size (L=R0−H−R1) obtained by subtracting a radial groove length (H) of said vane groove and a radial size (R1) of said recess portion from a radial size (R0) of said disc-like member satisfies a relation 66≦(L/2t), and
• wherein a shape of said vane groove on a side surface of said disc-like member is formed in such a manner as to expand a groove width from an inner portion in a radial direction toward an outer portion, and a shape between the vane grooves is formed in a substantially trapezoidal shape in which a width is reduced from the inner portion in the radial direction toward the outer portion.

An impeller for a circumferential current pump which is provided with a plurality of vane grooves in an outer peripheral side of a synthetic resin disc-like member rotated by a motor and is rotatably received within a substantially disc-like space formed between a pump casing and a pump cover, wherein a recess portion having a predetermined radius around a center of rotation is formed on at least one of one side surface opposing to said pump casing of said disc-like member and another side surface opposing to said pump cover, and a plurality of grooves extending in a radial direction within the recess portion are formed in a radial shape, and wherein a shape of said vane groove on a side surface of said disc-like member is formed in such a manner as to expand a groove width from an inner portion in a radial direction toward an outer portion, and a shape between the vane grooves is formed in a substantially trapezoidal shape in which a width is reduced from the inner portion in the radial direction toward the outer portion.

An impeller for a circumferential current pump which is provided with a plurality of vane grooves in an outer peripheral side of a synthetic resin disc-like member rotated by a motor and is rotatably received within a substantially disc-like space formed between a pump casing and a pump cover, wherein a recess portion having a predetermined radius around a center of rotation is formed on at least one of one side surface opposing to said pump casing of said disc-like member and another side surface opposing to said pump cover,

• wherein a ratio (L/2t) between the sum (t1+t2=2t) of a gap (t1) between said one side surface and said pump casing and a gap (t2) between said another side surface and said pump cover, and a size (L=R0−H−R1) obtained by subtracting a radial groove length (H) of said vane groove and a radial size (R1) of said recess portion from a radial size (R0) of said disc-like member satisfies a relation 66≦(L/2t), and
• wherein a corner portion in a bottom portion of said vane groove is beveled.

An impeller for a circumferential current pump which is provided with a plurality of vane grooves in an outer peripheral side of a synthetic resin disc-like member rotated by a motor and is rotatably received within a substantially disc-like space formed between a pump casing and a pump cover, wherein a recess portion having a predetermined radius around a center of rotation is formed on at least one of one side surface opposing to said pump casing of said disc-like member and another side surface opposing to said pump cover, and a plurality of grooves extending in a radial direction within the recess portion are formed in a radial shape, and wherein a corner portion in a bottom portion of said vane groove is beveled.