Carrier Corporation

Shahrokh Etemad

Donald Yannascoli

Howard H Fraser, Jr

Michael Hatzikazakis

William R Lane

Thomas L Kassouf

William J Boonzha

The crankshaft and orbiting scroll of a scroll compressor are drivingly connected through a bearing. The bearing is made up of a plurality of roller elements of varying diameters in line contact with both the crankshaft and the orbiting scroll and serving to locate the crankshaft and orbiting scroll eccentrically with respect to each other and thereby provide radial compliancy.

Rolling element radial compliancy mechanism

The scroll elements of a scroll-type compressor are treated employing a lapping tool to achieve increased flatness of the base surface and increased smoothness of the side walls of the involute wrap. This reduces flank leakage, tip leakage, and thrust friction losses. The lapping device that is placed against the scroll element has a radially extending base and a generally spiral wrap, the wrap generally matching that of the scroll element workpiece. The lapping device wrap has axially erect walls and a radially flat tip surface. After engaging the scroll element work piece, the lapping device is moved relative to the scroll element in an orbiting motion. A suitable lapping compound is introduced at least between the lapping device wrap tip surface and the base surface of the scroll element, and, if desired, also between the side walls of the lapping device wrap and the side walls of the scroll element wrap. The lapping compound can be introduced directly or in a gas flow.

Lapping of involute spiral scroll element

Leakage in a scroll wrap compressor is reduced by providing a roughened scroll wrap tip surface at the gap between the tip and the cooperating base so as to increase the frictional resistance to flow of fluid through the gap and to cause turbulence within the gap to further increase the resistance to the flow of fluid from the high pressure to the low pressure side across a scroll wrap tip. Various types of surfaces are shown for increasing the frictional resistance to flow such as knurling, grooving, cast cavities, metal particles and fibers and the like.

Method and apparatus for reducing scroll compressor tip leakage

A scroll compressor has a pair of mating scrolls that are disposed on parallel, eccentric axes, and each of these scrolls has a scroll plate and a spiral, involute wrap. The scrolls are driven so that one of them orbits about the axis of the other scroll while maintaining a fixed azimuthal relationship to it. The orbital motion causes a compressible fluid to enter at the periphery of the scrolls, and be carried and compressed by pockets formed between the mating wraps of these scrolls. The compressed gas is discharged out a discharge port at the center of one of the scrolls. The discharge port is bored diagonally into the scroll plate of the one scroll so that it has an elongated elliptical aperture at the center of the scroll plate. The port is machined into the scroll from the wrap side of the scroll. The enlarged size of the port aperture reduces the resistance to fluid flow and hence reduces the back pressure, thereby increasing the compressor efficiency.

Scroll compressor with enhanced discharge port

The orientation of the elements of a slider block radial compliance mechanism for a scroll compressor is such that the point of application of the actuating force is shifted from a first line extending through the center of gravity of the counterweight and the axis of the crankshaft to a second line parallel to said first line and extending through the axis of the orbiting scroll. The result of the changed orientation is an increase in the magnitude of both the sealing force between the scroll elements and the actuating force to move the mechanism.

Slider block radial compliance mechanism

Axial compliancy is achieved in a scroll compressor by providing a fluid pressure bias to the back of the orbiting scroll. The fluid pressure bias is supplied by one or more pockets configured to combine the efficient use of the available area with ease of manufacture.

Scroll compressor with axial compliancy

A multi-functional, single member serves as a muffler to attenuate noise, as a separator plate between the suction and discharge gases/pressures, and to carry check valve structure to avoid reverse rotation and for efficiency enhancement at off-design conditions.

Muffler/check valve assembly for scroll compressor

A high side hermetic scroll compressor passes the discharge gas along the interior of the shell and is thereby cooled prior to being subjected to a centrifugal separation to remove the oil before being discharged from the compressor. The separated oil is returned to the sump via a fluid path isolated from the discharge gas.

Scroll compressor with plural discharge flow paths

A scroll compressor can be provided with different wrap thicknesses to compensate for the different material properties of the orbiting and fixed scroll elements. The concept of different wrap thicknesses also aids in the select-fitting of parts and in the provision of and adjustment of a clearance or spacing between the wrap elements. Additionally, in the manufacture of a scroll compressor, the total wrap thickness of the two wraps is kept constant within narrow tolerances while the individual wrap thicknesses are allowed to vary over a predetermined range. The cutting tools used are sized such that even if they differ in their cutting diameters, the combined cutting diameters, and therefore the total wrap thicknesses, are constant within narrow tolerances. This permits the tools to be used and resharpened until their cutting diameters fall below the minimum acceptable diameter.

Scroll machine with wraps of different thicknesses

An orientation insensitive scroll compressor is assembled by assembling the internal compressor as on an assembly which is inserted into a middle shell. The tubes are inserted and then the top and bottom shells are partially inserted into the middle shell and secured in place.

Method of assembling scroll compressors

A scroll compressor is run with a clearance between the wraps and oil is injected between the wraps for sealing. In addition to providing a sealing function, the oil also provides a lubrication function prior to injection.

Method of lubricating a scroll compressor

Lubrication oil is supplied to provide a thrust force tending to keep the fixed and orbiting scroll means together in opposition to the forces acting thereon due to compressing gas between the wraps.

Scroll compressor with oil thrust force on orbiting scroll

In a high side scroll compressor, the motor is located above the scrolls and the oil sump and discharge gas are isolated from each other. The compressor can be used in an orientation that can range between vertical and at least 20.degree. of horizontal.

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Stratford, CT, United States of America

Shahrokh Etemad