Centrifugal pumps composed primarily of plastic components

Claim 1

In a centrifugal pump which is adapted to be used for circulating water in a swimming pool and which is composed primarily of plastic components, a housing having a wall formed with an inlet through which liquid is sucked into the pump, rotary impeller means coaxial with said inlet and located immediately adjacent said wall, the latter carrying a wearresistant disc of substantial rigidity which has an exposed surface directed toward said rotary impeller means and defining a narrow gap therewith, said housing wall being made of plastic molded directly onto said disc to be bonded therewith and said disc having a portion embedded in the plastic of said wall, as a result of the molding of the latter onto said disc, with a part of the plastic of said wall situated between said portion of said disc and a plane which contains said exposed surface of said disc, so that said disc is reliably fixed to said wall, said portion of said disc being formed by a peripheral edge region of said disc which forms part of a cone whose apex is situated in the common axis of said impeller means and inlet at the side of said impeller means opposite from said inlet, so that said disc has directed away from said impeller means a surface of a greater diameter than said exposed surface and concentric therewith, said surface of said disc which is of said greater diameter being completely covered by the plastic of said wall and the plastic of said wall also covering the tapered periphery of said disc which is at the side thereof opposite from said surface of greater diameter.