Volumetric compressor of the roots type

• US 4,455,132 A
• Filed: 02/23/1983
• Issued: 06/19/1984
• Est. Priority Date: 02/23/1982
• Status: Expired due to Term

• Current Assignee: FIAT OTTO Company Limited
• Original Assignee: Fiat Auto S.p.A.
• Inventors: Messori, Pier P.
• Primary Examiner(s): Smith, Leonard E.
• Assistant Examiner(s): Obee, Jane E.
• Application Number:
  US06/468,839
• Time in Patent Office: 482 Days
• Field of Search: 418/150, 418/191, 418/206, 418/201
• US Class Current: 418/206.5
• CPC Class Codes: F04C 18/126 with radially from the rotor body extending elements, not necessarily co-operating with corresponding recesses in the other rotor, e.g. lobes, Roots type

Abstract

A Roots-type rotary volumetric compressor with two double-lobed rotors in which, for each of the four quadrants defined by the major and minor axes of the rotor, each rotor has a particular profile constituted by seven arcs of circles which extend from the point of intersection with the minor axis to the point of intersection with the major axis. The coordinates of the respective centers of curvature (C₁ to C₇) of the arcs in a frame of reference having its origin at the center of the rotor and its axes of the asbcissae (X) and ordinates (Y) coincident with the minor and major axes of the rotor, and the values of the respective radii of curvature (R₁ to R₇), are given. The arcs have respective angular extents (A₁ to A₇) of substantially 12°, 40°, 1°, 29°, 88°, 13° and 6°.

Claims

1. A rotary volumetric compressor of the Roots type, including two double-lobed rotors with respective axes of rotation and respective major and minor axes, wherein each rotor has a profile which, for each of the four quadrants defined by the major and minor axes of the rotor, is constituted by seven arcs of circles extending from the point of intersection with the minor axis to the point of intersection with the major axis, and wherein the coordinates (XC₁ to XC₇ ;

YC₁ to YC₇) of the respective centres of curvature (C₁ to C₇) of the arcs in a frame of reference having its origin at the centre of the rotor, its axis of the abscissae (X) coincident with a minor semi-axis of the rotor, and its axis of the ordinates (Y) coincident with a major semi-axis of the rotor, and the values of the respective radii of curvature (R₁ to R₇) of the arcs, are as follows;

XC₁ =0.538972 d;

YC₁ =0;

R₁ =0.354967 d;

XC₂ =0.581260 d;

YC₂ =-0.005147 d;

R₂ =0.397564 d;

YC₃ =-0.671833

YC₃ =1.311256 d;

R₃ =1.419868 d;

XC₄ =0.239369 d;

YC₄ =0.379889 d;

R₄ =0.116903 d;

XC₅ =0;

YC₅ =0.449147 d;

R₅ =0.366084 d;

XC₆ =0.070711 d;

YC₆ =0.661797 d;

R₆ =0.141988 d;

XC₇ =0;

YC₇ =0;

R₇ =0.807550 d;

where d is the distance between the axes of rotation of the two rotors.

2. A compressor as defined in claim 1, wherein the respective angular extents (A₁ to A₇) of the seven arcs have substantially the following values:

A₁ =12°

;

A₂ =40°

;

A₃ =1°

;

A₄ =29°

;

A₅ =88°

;

A₆ =13°

;

A₇ =6°

.