Food centrifugal pump formed by stamping and welding having a seal arrangement between the impeller and casing

A food centrifugal pump comprising:

• a single-piece pump casing having a first inlet pipe opening along an axis of the casing, an outlet pipe opening, and a cover opening, the casing also including an annular inclined wall adjacent to the first inlet pipe opening and extending to the first inlet pipe opening obliquely at an angle β;
• a cover mounted in the cover opening;
• a single-piece bracket having a second inlet pipe opening along an axis of the bracket, the bracket being secured to the casing outside of the first inlet pipe opening, the second inlet pipe opening aligned with the first inlet pipe opening;
• a separate inlet pipe secured to the first inlet pipe opening, the inlet pipe extending through and secured to the second inlet pipe opening;
• a separate outlet pipe secured to the outlet pipe opening;
• a motor and a shaft extending from the motor through the cover and into the casing;
• and
• an impeller supported for rotation in the casing on the shaft, the impeller having a back plate and a plurality of single-piece blades, each blade having a U-shaped cross section defining a yoke and a pair of spaced-apart legs, the yoke being secured to the back plate and the legs extending perpendicular to the yoke so as to form an open channel, wherein the legs extend radially outward along circular arc paths from an interior portion of the back plate towards an outer circumference of the back plate, the spacing between the pair of legs on each blade being greatest near the outer edge, and wherein an outer edge of each leg slopes obliquely at an angle α equal to the angle β, the legs being in close proximity to the annular wall to define an end surface seal between the impeller and the annular inclined wall.

A method of making a food centrifugal pump comprising:

• forming a casing by stamping a single metal plate so as to have a first inlet pipe opening along an axis of the casing, an outlet pipe opening, a cover opening, and an annular wall adjacent to the first pipe opening, the annular wall extending to the first inlet pipe opening obliquely at an angle β;
• welding an inlet pipe to the first inlet pipe opening;
• welding an outlet pipe to the outlet pipe opening;
• forming a bracket by stamping a single metal plate so as to have a second inlet pipe opening along an axis of the bracket;
• mounting the bracket to the casing with the inlet pipe extending through the second inlet pipe opening;
• welding one end of the bracket to the casing outside of the first inlet pipe opening;
• welding the second inlet pipe opening to the inlet pipe;
• forming a plurality of blades by stamping a plurality of single metal plates, each blade having a U-shaped cross section defining a yoke and a pair of spaced-apart legs, each leg extending from one end of the blade and extending along a circular arc path towards an opposite end, the spacing between the leg pair on each blade being greatest at the opposite end, and wherein an outer edge of each leg slopes obliquely at an angle α equal to the angle β;
• welding the yoke of each blade to an impeller back plate with the legs extending perpendicular to the yoke so as to form an open channel;
• mounting the impeller back plate to a shaft of a motor;
• and
• mounting the motor with the casing with the outer edge of each leg in close proximity to the annular wall to define an end surface seal between each leg and the annular wall.