Patent Description:
A scroll compressor is a certain type of compressor that is used to compress refrigerant for such applications as refrigeration, air conditioning, industrial cooling and freezer applications, and/or other applications where compressed fluid may be used. Such prior scroll compressors are known, for example, as exemplified in <CIT>; <CIT>; <CIT>; <CIT> and <CIT>, all of which are assigned to a Bitzer entity closely related to the present assignee. The present disclosure pertains to improvements that can be implemented in these or other scroll compressor designs.

Additionally, particular embodiments of scroll compressors are disclosed in <CIT>, <CIT>. , and <CIT>, <CIT> discloses a compressor and is directed to an oil separator through which refrigerant flows after flowing around the drive motor with a motor housing and before entering a scroll compressor and the refrigerant is supplied via a suction line which guides the refrigerant through the motor housing. <CIT> discloses a compressor and is directed to the flow of the refrigerant around the motor and refrigerant flows through a coupling directly to a housing of the motor. <CIT> discloses a hermetic compressor unit. <CIT> discloses a scroll compressor and is directed to a suction screen member at the inlet of the scroll compressor. <CIT> relates to a scroll type compressor having a structure that a lower end portion of a suction pipe is joint to a suction opening of a fixed scroll through an O-ring. <CIT> relates to an economizer tube assembly as part of an economizer cycle to increase the efficiency of a cooling cycle, the economizer tube assembly includes an economizer fitting connected to an economizer fitting extension.

As is exemplified by these patents, scroll compressors conventionally include an outer housing having a scroll compressor contained therein. A scroll compressor includes first and second scroll compressor members. A first compressor member is typically arranged stationary and fixed in the outer housing. A second scroll compressor member is moveable relative to the first scroll compressor member in order to compress refrigerant between respective scroll ribs which rise above the respective bases and engage in one another. Conventionally the moveable scroll compressor member is driven about an orbital path about a central axis for the purposes of compressing refrigerant. An appropriate drive unit, typically an electric motor, is provided usually within the same housing to drive the movable scroll member.

The present invention pertains to improvements in the state of the art.

The present invention is directed toward a scroll compressor with a suction fitting member, that may be used to bridge the distance between an inlet fitting and an internal suction duct within a scroll compressor housing.

The scroll compressor includes an outer housing having an inside diameter and a suction port defined in a wall of the outer housing. A suction duct is disposed inside the outer housing a spaced distance from the wall of the outer housing with the suction duct defining an entrance port aligned with the suction port.

The suction fitting includes a first member and a second member with the second member configured to slide through the first member to engage the suction duct disposed in the outer housing.

The first member is generally cylindrical and has a body portion with a second inside diameter and a nose portion with a first inside diameter. The second inside diameter is larger than the first inside diameter and the nose portion is disposed in the suction port defined in the outer housing.

The second member is generally cylindrical and has a body portion with a second outside diameter and a nose portion with a first outside diameter. The second outside diameter is larger than the first outside diameter with the second member disposed inside the first member with the nose portion of the second member extending into the outer housing through the suction port and spanning the spaced distance to the suction duct. The nose portion of the second member couples with the entrance port of the suction duct. Neither the first member nor the second member includes a suction screen for filtering out solid contaminants in a flow of refrigerant.

In one embodiment, an annular land is defined inside the first member by a change of inside diameter from the second inside diameter to the first inside diameter. The annular land is configured to butt against the body portion of the second member creating an annular seal of the second member to the first member. With second member sealed against the first member and with the nose portion of the second member engaged with the suction duct, substantially all of the fluid flow into the compressor housing does not bypass the suction duct since the nose portion bridges the spaced distance between the inside wall of the outer housing and the suction duct.

In another embodiment, the change of inside diameter is defined by a curve from the second inside diameter to the first inside diameter of the first member. In another embodiment, a series of annular steps may define the change of inside diameter of the first member.

With the second member installed in the first member and engaged with the entrance port, an unimpeded fluid flow path from a distal end of the first member to the suction duct is established. With the fluid flow not impeded through the suction fitting, a reduction of pressure drop along the flow path results in an increase in compressor efficiency.

In an embodiment, the suction fitting second member is composed of sheet metal, and the suction fitting first member is a turned steel component. In certain embodiments, the first member defines a first inner-most diameter, and the second member defines a second inner-most diameter, and, to reduce a flow restriction through the suction fitting. The second inner-most diameter is at least <NUM>% of the diameter of the first inner-most diameter.

In at least one embodiment, the flow of refrigerant is directed through an opening of the second member, the opening having a cross-sectional area of at least <NUM> sq.

In more particular embodiments, the second member provides a limiting flow restriction, wherein, by being free of a suction screen, the limiting flow restriction is no greater than <NUM> psi, corresponding to about <NUM>,<NUM> bar, gage at a flow rate of <NUM> cubic feet per minute (cfm), corresponding to about <NUM>,<NUM><NUM> per min, through the suction fitting. The scroll compressor may include a suction duct screen disposed in the suction duct, the suction duct screen having no contact with the suction fitting.

There is also disclosed a method for installing a suction fitting in a scroll compressor. The scroll compressor includes an outer housing having an inside diameter and a suction port defined in a wall of the outer housing. A suction duct is disposed in the outer housing a spaced distance from the wall of the outer housing. The suction duct defines an entrance port aligned with the suction port.

The method includes installing a first member of the suction fitting into the suction port. The first member is generally cylindrical and has a body portion with a second inside diameter and a nose portion with a first inside diameter. The second inside diameter is larger than the first inside diameter and the nose portion is disposed in the suction port. The nose portion extends into the wall defining the suction port.

A second member of the suction fitting is inserted into the first member with the second member being generally cylindrical and having a body portion with a second outside diameter and a nose portion with a first outside diameter. The second outside diameter is larger than the first outside diameter with the second member disposed inside the first member with the nose portion of the second member extending through the wall of the outer housing through the suction port. The nose portion is spanning the spaced distance to the suction duct and coupling with the entrance port of the suction duct. In this method, neither the first member nor the second member includes a suction screen for filtering out solid contaminants in a flow of refrigerant.

The method includes butting the body portion of the second member against an annular land defined by a change of inside diameter of the first member from the second inside diameter to the first inside diameter. In one embodiment, the change of inside diameter is defined by a curve from the second inside diameter to the first inside diameter. With the second member inserted into the first member and engaging the suction duct an unimpeded fluid flow path is established from a distal end of the first member to the suction duct with the second member installed in the first member and engaged with the entrance port.

On the contrary, the intent is to cover all modifications as included within the scope of the invention as defined by the appended claims.

A prior art embodiment of a scroll compressor is illustrated in <FIG>. An embodiment of the present invention is illustrated in <FIG> as a scroll compressor assembly <NUM> generally including an outer housing <NUM> in which a scroll compressor <NUM> can be driven by a drive unit <NUM>. The scroll compressor assembly <NUM> may be arranged in a refrigerant circuit for refrigeration, industrial cooling, freezing, air conditioning or other appropriate applications where compressed fluid is desired. Appropriate connection ports provide for connection to a refrigeration circuit and include a refrigerant inlet port, also referred to as a suction port <NUM>, and a refrigerant outlet port <NUM> extending through the outer housing <NUM>. The scroll compressor assembly <NUM> is operable through operation of the drive unit <NUM> to operate the scroll compressor <NUM> and thereby compress an appropriate refrigerant or other fluid that enters the refrigerant inlet port <NUM> and exits the refrigerant outlet port <NUM> in a compressed high-pressure state.

A scroll compressor assembly with an inlet fitting and suction screen member is disclosed in <CIT>. The suction screen disclosed in the '<NUM> patent, like that shown in <FIG>, is configured to screen out solid contaminants in the flow of refrigerant. However, the suction screen does interfere, at least to some degree, with the flow of refrigerant, which results in a pressure drop which could adversely affect the efficiency of the compressor. In some scroll compressors, a larger screen may be placed in the suction duct <NUM>. <CIT> discloses scroll compressors having screens in the suction duct for filtering out solid contaminants from refrigerant gas.

In particular embodiments, the larger screen results in a lower pressure drop and increased efficiency due to a decreased interference with the flow of refrigerant. As will be shown below, the present invention relates to suction fittings first and second members of which do not include a suction screen. It is envisioned that these screenless suction fittings may be used in conjunction with larger screens located either in the suction duct or elsewhere within the compressor housing. This configuration typically allows for greater flow of refrigerant flow than in conventional scroll compressors having suction screens designed to fit through the inlet fitting.

The outer housing <NUM> may take many forms. In the preferred embodiment, the outer housing includes multiple shell sections and preferably three shell sections to include a central cylindrical housing section <NUM>, a top end housing section <NUM> and a bottom end housing section <NUM>. Preferably, the housing sections <NUM>, <NUM>, <NUM> are formed of appropriate sheet steel and welded together to make a permanent outer housing <NUM> enclosure. However, if disassembly of the housing is desired, other housing provisions can be made that can include metal castings or machined components.

The central housing section <NUM> is preferably cylindrical and telescopically interfits with the top and bottom end housing sections <NUM>, <NUM>. This forms an enclosed chamber <NUM> for housing the scroll compressor <NUM> and drive unit <NUM>. Each of the top and bottom end housing sections <NUM>, <NUM> are generally dome shaped and include respective cylindrical side wall regions <NUM>, <NUM> to mate with the center section <NUM> and provide for closing off the top and bottom ends of the outer housing <NUM>. As can be seen in <FIG>, the top side wall region <NUM> telescopically overlaps the central housing section <NUM> and is exteriorly welded along a circular welded region to the top end of the central housing section <NUM>. Similarly the bottom side wall region <NUM> of the bottom end housing section <NUM> telescopically interfits with the central housing section <NUM> (but is shown as being installed into the interior rather than the exterior of the central housing section <NUM>) and is exteriorly welded by a circular weld region.

The drive unit <NUM> may preferably take the form of an electrical motor assembly <NUM>, which is supported by upper and lower bearing members <NUM>, <NUM>. The motor assembly <NUM> operably rotates and drives a shaft <NUM>. The electrical motor assembly <NUM> generally includes an outer annular motor housing, a stator comprising electrical coils and a rotor that is coupled to the drive shaft <NUM> for rotation together. Energizing the stator is operative to rotatably drive the rotor and thereby rotate the drive shaft <NUM> about a central axis.

During operation, the scroll compressor assembly <NUM> is operable to receive low-pressure refrigerant at the housing inlet port <NUM> and compress the refrigerant for delivery to the high-pressure chamber, where it can be output through the housing outlet port <NUM>. As shown in <FIG>, a suction duct <NUM> is connected internally of the housing <NUM> to guide the lower-pressure refrigerant from the inlet port <NUM> into housing and beneath the motor housing. This allows the low-pressure refrigerant to flow through and across the motor and thereby cool and carry heat away from the motor which can be caused by operation of the motor. Low-pressure refrigerant can then pass longitudinally through the motor housing and around through void spaces therein toward the top end where it can exit through a plurality of motor housing outlets that are equally angularly spaced about the central axis. The motor housing outlets may be defined either in the motor housing, the upper bearing member or by a combination of the motor housing and upper bearing member.

Upon exiting the motor housing outlet, the low-pressure refrigerant enters an annular chamber <NUM> formed between the motor housing and the outer housing. From there, the low-pressure refrigerant can pass through the upper bearing member through a pair of opposed outer peripheral through ports that are defined by recesses on opposed sides of the upper bearing member <NUM> to create gaps between the bearing member <NUM> and housing <NUM>. Upon passing through the upper bearing member <NUM> the low-pressure refrigerant finally enters the intake area of the scroll compressor bodies. From the intake area, the lower-pressure refrigerant finally enters the scroll ribs on opposite sides and is progressively compressed through chambers to where it reaches it maximum compressed state at the compression outlet where it subsequently passes through the check valve and into the high-pressure chamber. From there, high-pressure, compressed refrigerant may then pass from the scroll compressor assembly <NUM> through the refrigerant housing outlet port <NUM>.

Referring to <FIG>, it is seen that a screenless suction duct <NUM> is preferably employed to direct incoming fluid flow (e.g. refrigerant) from the housing inlet <NUM> to the stator housing. To provide for the inlet port <NUM>, the housing includes an inlet opening <NUM> in which a suction fitting <NUM> is provided that may include a connector such as threads or other such connection means such as a barb or quick connect coupler, for example. The suction fitting <NUM> is welded to the housing shell in engagement with the inlet opening <NUM>. The inlet opening <NUM> and the suction fitting <NUM> are thereby provided for communicating the refrigerant into the housing.

The suction fitting is provided to form a common bridge and thereby communicate refrigerant from the inlet <NUM> through the entrance opening and port <NUM> formed in the suction duct <NUM>. Substantially all (in other words - all or most) of the incoming refrigerant is thereby directed through the suction fitting <NUM>. Once passing through the suction fitting, refrigerant is then directed by the suction duct <NUM> to a location upstream and at the entrance of the motor housing.

Turning in greater detail to the suction duct <NUM>, and referring to <FIG>, it is seen that the suction duct comprises a stamped sheet steel metal body having a wall thickness with an outer generally rectangular and arcuate mounting flange which surrounds a duct channel that extends between a top end and a bottom end. The entrance opening and port is formed through a channel bottom proximate the top end. This opening and port provide means for communicating and receiving fluid from the inlet <NUM> via a suction fitting <NUM> which is received through the outer compressor housing wall <NUM> and into duct channel of the suction duct <NUM>.

Preferably, the suction duct <NUM> is a metal stamping of sheet metal to provide the body and wall structure of the suction duct <NUM> as a unitary member. The rectangular and arcuate mounting flange and the duct channel can readily be stamped into the sheet metal to provide an elongated duct channel and bottom grooves as well as the fastener holes. The entrance port <NUM> is also formed by stamping and punching out the generally circular opening from the sheet metal. Material stamp forming of the punched out area creates an annular opening flange <NUM> defining the entrance port <NUM>, which projects from the channel bottom toward the mounting flange. The annular opening flange <NUM> tapers as it extends radially inward and away from the channel bottom of the suction duct so as to provide a tapered guide surface that facilitates insertion and assembly of the suction fitting into engagement and received within the suction duct <NUM>.

Turning in greater detail to the suction fitting <NUM> with additional reference to <FIG>, the suction fitting as shown in <FIG>, bridges the gap or spaced distance, between the inlet <NUM> and the internal suction duct <NUM>. As shown, the entrance port <NUM> of the suction duct <NUM> is aligned with the inlet port <NUM> formed by the inlet opening <NUM> for the compressor housing. Preferably these openings are diametrically and concentrically aligned. The suction fitting acts as a bridging function bridging the spaced distance between the suction inlet <NUM> and the suction duct <NUM>.

This disclosure describes a suction fitting <NUM> coupled to a scroll compressor <NUM>. The scroll compressor <NUM> includes an outer housing <NUM> having an inside diameter and a suction port <NUM> defined in a wall <NUM> of the outer housing <NUM>. A suction duct <NUM> is disposed inside the outer housing <NUM> a spaced distance from the wall <NUM> of the outer housing <NUM> with the suction duct <NUM> defining an entrance port <NUM> aligned with the suction port <NUM>.

The suction fitting <NUM> includes a first member <NUM> and a second member <NUM> with the second member <NUM> configured to slide through the first member <NUM> to engage the suction duct <NUM> disposed in the outer housing <NUM>.

The first member <NUM> is generally cylindrical and has a body portion <NUM> with a second inside diameter <NUM> and a nose portion <NUM> with a first inside diameter <NUM>. The second inside diameter <NUM> is larger than the first inside diameter <NUM> and the nose portion <NUM> is disposed in the suction port <NUM> defined in the outer housing <NUM>.

The second member <NUM> is generally cylindrical and has a body portion <NUM> with a second outside diameter <NUM> and a nose portion <NUM> with a first outside diameter <NUM>. The second outside diameter <NUM> is larger than the first outside <NUM> diameter with the second member <NUM> disposed inside the first member <NUM> with the nose portion <NUM> of the second member <NUM> extending into the outer housing <NUM> through the suction port <NUM> and spanning the spaced distance to the suction duct <NUM>. The nose portion <NUM> of the second member <NUM> couples with the entrance port <NUM> of the suction duct <NUM>.

In another embodiment, an annular land <NUM> is defined inside the first member <NUM> by a change of inside diameter from the second inside diameter <NUM> to the first inside diameter <NUM>. The annular land <NUM> is configured to butt against the body portion <NUM> of the second member <NUM> creating an annular seal <NUM> of the second member <NUM> to the first member <NUM>. The second member <NUM> sealed against the first member <NUM> and with the nose portion <NUM> of the second member <NUM> engaged with the suction duct <NUM>, substantially all of the fluid flow into the compressor housing <NUM> does not bypass the suction duct <NUM> since the nose portion <NUM> bridges the spaced distance between the inside face of the wall <NUM> of the outer housing <NUM> and the suction duct <NUM>.

In an embodiment, the change of inside diameter is defined by a curve <NUM> from the second inside diameter <NUM> to the first inside diameter <NUM> of the first member <NUM>. A series of annular steps may also alternatively define the change of inside diameter of the first member.

With the second member <NUM> installed in the first member <NUM> and engaged with the entrance port <NUM>, and by omitting any type of suction screen on the suction fitting <NUM>, an unimpeded fluid flow path from a distal end <NUM> of the first member <NUM> to the suction duct <NUM> is established. With the fluid flow not impeded through the suction fitting <NUM>, a reduction of the pressure drop, normally associated with conventional fittings having a suction screen, along the flow path results in an increase in compressor efficiency.

In an embodiment, the suction fitting second member <NUM> is composed of sheet metal, and the first member <NUM> is composed of turned steel.

There is also disclosed a method for installing a suction fitting <NUM> in a scroll compressor assembly <NUM>. The scroll compressor assembly <NUM> includes an outer housing <NUM> having an inside diameter and a suction port <NUM> defined in a wall <NUM> of the outer housing <NUM>. A suction duct <NUM> is disposed in the outer housing <NUM> a spaced distance from the wall <NUM> of the outer housing <NUM>. The suction duct <NUM> defines an entrance port <NUM> aligned with the suction port <NUM>.

The method includes installing a first member <NUM> of the suction fitting <NUM> into the suction port <NUM>. The first member <NUM> is generally cylindrical and has a body portion <NUM> with a second inside diameter <NUM> and a nose portion <NUM> with a first inside diameter <NUM>. The second inside diameter <NUM> is larger than the first inside diameter and the nose portion <NUM> is disposed in the suction port <NUM>. The nose portion <NUM> extends into the wall <NUM> defining the suction port <NUM>.

A second member <NUM> of the suction fitting <NUM> is inserted into the first member <NUM> with the second member <NUM> being generally cylindrical and having a body portion <NUM> with a second outside diameter <NUM> and a nose portion <NUM> with a first outside diameter <NUM>. The second outside diameter <NUM> is larger than the first outside diameter <NUM> with the second member <NUM> disposed inside the first member <NUM> with the nose portion <NUM> of the second member <NUM> extending through the wall <NUM> of the outer housing <NUM> through the suction port <NUM>. The nose portion <NUM> spans the spaced distance to the suction duct <NUM> and couples with the entrance port <NUM> of the suction duct <NUM>.

The method includes butting the body portion <NUM> of the second member <NUM> against an annular land <NUM> defined by a change of inside diameter of the first member <NUM> from the second inside diameter <NUM> to the first inside diameter <NUM>. In one embodiment, the change of inside diameter is defined by a curve <NUM> from the second inside diameter <NUM> to the first inside diameter <NUM>. With the second member <NUM> inserted into the first member <NUM> and engaging the suction duct <NUM> an unimpeded fluid flow path is established from a distal end <NUM> of the first member <NUM> to the suction duct <NUM> with the second member <NUM> installed in the first member <NUM> and engaged with the entrance port <NUM> forming an annular seal <NUM>.

As explained above, in certain embodiments, the first member <NUM> has second inside diameter <NUM>, while the second member <NUM> has first inside diameter <NUM>. To reduce a flow restriction through the suction fitting <NUM>, the first inside diameter <NUM> is at least <NUM>% of the diameter of the second inside diameter <NUM>.

In at least one embodiment, the flow of refrigerant is directed through an opening of the second member <NUM>, the opening having a minimum cross-sectional area of at least <NUM> sq.

In more particular embodiments, the second member <NUM> provides a limiting flow restriction, wherein, by being free of a suction screen, the limiting flow restriction is no greater than <NUM> psi, corresponding to about <NUM>,<NUM> bar, gage at a flow rate of <NUM> cubic feet per minute (cfm), corresponding to about <NUM>,<NUM><NUM> per min, through the suction fitting <NUM>. The scroll compressor <NUM> may include a suction duct screen disposed in the suction duct <NUM>, the suction duct screen having no contact with the suction fitting <NUM>.

Recognizing that there can be tolerance issues and/or assembly inaccuracies that result in slight misalignments between the suction duct and the inlet fitting in their respective openings, different means are contemplated for accommodating misalignment. For example, in the present embodiment, the second member <NUM> provides a surface of the nose portion <NUM> that helps to self locate during installation, as it can co-act with a tapered guide surface on the suction duct <NUM> to guide insertion. The second member <NUM> is configured to be closely received into complete or almost complete circular engagement with the opening flange <NUM> of the suction duct <NUM>.

For purposes of this disclosure, the term "coupled" means the joining of two components (electrical or mechanical) directly or indirectly to one another. Such joining may be stationary in nature or moveable in nature. Such joining may be achieved with the two components (electrical or mechanical) and any additional intermediate members being integrally formed as a single unitary body with one another or the two components and any additional member being attached to one another. Such adjoining may be permanent in nature or alternatively be removable or releasable in nature.

Claim 1:
A scroll compressor (<NUM>) with a suction fitting (<NUM>) coupled to the scroll compressor (<NUM>), the scroll compressor (<NUM>) including an outer housing (<NUM>) having an inside diameter and a suction port (<NUM>) defined in a wall (<NUM>) of the outer housing (<NUM>), and a suction duct (<NUM>) disposed inside the outer housing (<NUM>) a spaced distance from the wall (<NUM>) of the outer housing (<NUM>), with the suction duct (<NUM>) defining an entrance port (<NUM>) aligned with the suction port (<NUM>), characterized in that the suction fitting (<NUM>) comprising:
a first member (<NUM>) being generally cylindrical and
a second member (<NUM>) being generally cylindrical, with the second member (<NUM>) disposed inside the first member (<NUM>) with a portion of the second member (<NUM>) extending into the outer housing (<NUM>) through the suction port (<NUM>) and spanning the spaced distance to the suction duct (<NUM>) and coupling with the entrance port (<NUM>) of the suction duct (<NUM>);
wherein neither the first member (<NUM>) nor the second member (<NUM>) includes a suction screen for filtering out solid contaminants in a flow of refrigerant.