Motor driven pump

A motor driven pump which;

• includes an impeller housing having inlet and delivery connections and having an impeller chamber with an impeller therein, an outer cylindrical casing connected to said impeller housing, and having end plates, one of which is a cylindrical sleeve extending between said end plates and providing therewith and with said outer casing an isolated motor stator chamber, a motor stator in said stator chamber, the interior of said sleeve providing a motor rotor chamber, the improvement which comprises
• first and second adaptors removably mounted within said sleeve at opposite ends thereof,
• said first adaptor being mounted adjacent said impeller and said second adaptor being mounted at the end opposite thereto,
• said adaptors being provided with O-ring means to permit limited axial alignment,
• said connecting end plate having a metering closure plate thereon,
• said metering closure plate having at least one variable orifice therein,
• said first adaptor having at least one passageway therealong connecting the interior of said sleeve to said impeller chamber through said variable orifice permitting controlled cooling fluid flow therethrough,
• a hollow shaft having sleeve bearings secured thereton, carried in said first and second adaptors, and extending into said impeller chamber, said impeller being mounted to said shaft in said impeller chamber,
• a motor rotor on said shaft between said bearings in said motor rotor chamber,
• said first and second adaptors have sleeves therein engaged with said bearings carried by said shaft,
• automatic thrust balancing means for balancing the axial forces on said shaft which includes,
• first magnetic ring means mounted on said adaptors facing said rotor and second magnetic ring means mounted on the ends of said rotor facing said adaptor ring means,
• said first and second magnetic ring means being arranged so that they repel each other whereby said rotor is automatically maintained in a thrust balanced condition.