US 6,236,897 B1 · Calculation and precision processing of cardiocle and expanded cardioid casing curved surfaces for eccentric rotor vane pumps

Abstract

This invention includes the derivation of the exact mathematical expressions for the curvature, either cardiocle or expanded cardioid, of the casing of the springless eccentric rotor vane pump, thereby facilitating the precision manufacture of the curved surfaces of the casing using CNC techniques. As a result, the capacity and accuracy of the eccentric rotor vane pump is greatly improved. As the section manufacture and assembly of the casing becomes possible, the mass production of large-sized pumps of 1-meter or larger diameter is now attainable, hitherto regarded as almost impossible, and therefore production cost is also reduced. The unique design which positions the axis of eccentricity in the lower central part of the axis of rotor rotation results in increase in the rotation speed of the rotor, and leads to reduction of friction between the vane ends and the curved surface of the casing as the weight of the vane does not affect the movement of the rotor.

Claims5

Dependent claims

A method of manufacturing casing curved surfaces for eccentric rotor vane pumps, wherein the cardiocle curvature of the casing in a springless eccentric rotor vane pump can be represented over the range 0°≦θ≦180° as

X2+Y2={2{square root over (r+L (2R−r+L ))}+(R−r)sin θ−{square root over (R2+L −(R−r+L )2 +L cos2+L θ)}}2,
P=2{square root over (r+L (2R−r+L ))}+(R−r)sin θ−{square root over (R2+L −(R−r+L )2+L cos2+L θ)}
P = 2 ⁢ a ⁡ ( 1 + ( R - r ) ⁢ sin ⁢ ⁢ θ 2 ⁢ a - R 2 - ( R - r ) 2 ⁢ ⁢ cos 2 ⁢ θ 2 ⁢ a ) ,
and
X2+Y2=({square root over (R2+L −(R−r+L )2 +L cos2+L θ)}−(R−r)sin θ)2, or
P={square root over (R2+L −(R−r+L )2+L cos2+L θ)}−(R−r)sin θ,
where X and Y are Cartesian coordinates, r denoites the radius of the rotor, R denotes the radius of the basic circle, θ denotes the rotation angle of the rotor or vane, and P is a polar coordinate, whereby the above equations being implemented in the precision manufacture of the curved surface of the casing in the eccentric rotor vane pump using CNC techniques.

4 more elements

Dependencies are inferred from the claim text.

Calculation and precision processing of cardiocle and expanded cardioid casing curved surfaces for eccentric rotor vane pumps

Life of this patent

Calculation and precision processing of cardiocle and expanded cardioid casing curved surfaces for eccentric rotor vane pumps

Life of this patent

Abstract

Claims5