Corrosion-resistant magnet pump

A corrosion-resistant magnet pump comprising a front casing, a rear casing provided behind the front casing with a partition wall interposed therebetween, a rotary shaft extending from the front casing into the rear casing and supported by a bearing provided at least in the partition wall, an impeller fixed to the rotary shaft within the front casing, a driven magnet drivingly connected to the rotary shaft within the rear casing, and a drive magnet provided outside the rear casing and drivingly rotatable by a motor, the portions of the pump to be exposed to a liquid being made of a corrosion-resistant material, the magnet pump being characterized in that the impeller is fixedly fastened to the rotary shaft by an impeller nut screwed on the front end of the rotary shaft and comprises a ceramic insert in the center of the impeller and the remaining portion of corrosion-resistant synthetic resin around the insert, the insert having a rear end face projecting rearward and serving as a thrust bearing face, the partition wall have a thrust bearing face opposed to the rear end face of the insert, the rotary shaft the impeller not being made of a corrosion-resistant synthetic resin lower in hardness than the material of being made of a corrosion-resistant material, the impeller insert, the impeller insert having a front end face projecting forward and formed with a multiplicity of nut engaging projections in a radial arrangement, the nut engaging projectings gradually projecting toward the impeller nut in the direction of tightening rotation of the impeller nut and subsequently recessed in a direction away from the impeller nut, the bearing bearing formed at an intermediate portion thereof with lubricant supply channels, the partition wall having bores opposed to the rear plate of the impeller for guiding the liquid within the front casing into the rear casing therethrough, the rear casing having a supply bore for supplying a lubricant from outside into the rear casing therethrough, guide blades for guiding the liquid from the rear casing into the bearing channels being provided on at least one of the surface of the partition wall and the surface of the rear casing defining the interior space of the rear casing.