TW201814163A - Compressor arrangement with integrated motor - Google Patents

Abstract

The invention refers to a rotary compressor arrangement (100) comprising a stationary member (40) centered at a shaft axis (X) and a rotary member (90) rotating around the stationary member (40); the stationary member (40) and the rotary member (90) being inside a hermetically sealed inner volume within the compressor arrangement (100); the compressor arrangement (100) comprising a stator (210) with a winding arrangement (211) generating an electromagnetic force inside the stator (210), the stator (210) being arranged outside the hermetically sealed inner volume; the compressor arrangement (100) further comprising a plurality of magnets (221) directly attached to the rotary member (90) and facing the winding arrangement (211) in the stator (210) such that the rotary member (90) is entrained in rotation by a rotating electromagnetic field from the stator (210). The invention further refers to a cooling/refrigerating system comprising such a rotary compressor arrangement (100).

Description

   Compressor configuration with integrated motor   

The present invention relates to a compressor configuration including an integrated motor, and more particularly to a vane-type rotary compressor configuration preferably used in a cooling or freezing system.

Currently, different types of compressors are used in cooling or freezing systems. A gas compressor is a mechanical device that increases the pressure of a gas by reducing the volume of the gas. Reducing the volume of the gas is by changing the state of the gas, and the temperature of the gas is also changed. Therefore, when the gas passes through a condenser, it can be used as a refrigerant in a refrigeration compressor.

For domestic applications, vane rotary compressors are often used as refrigeration compressors due to their reduced size. Generally, a vane rotary compressor includes a circular rotor that rotates inside a larger circular cavity configured on the inner wall of the compressor casing. The center of the rotor is offset from the center of the cavity, causing eccentricity. The blade is arranged in the rotor, and generally slides in and out of the rotor, and is stretched to seal on the inner wall of the cavity to establish a blade in which a working fluid (generally a refrigerant gas) is compressed. room. During the suction portion of the cycle, the refrigerant gas enters a compression chamber through an inlet port, where the volume is reduced by the eccentric motion of the rotor, and then the compressed fluid is discharged through an outlet port.

Despite the advantages of small size vane rotary compressors, the leakage of refrigerant through the inner wall surface of the compressor casing is a disadvantage. This is why these compressors also use lubricating oil. Lubricating oil has two main functions: one is to lubricate moving parts, and the other is to seal the clearance between these moving parts, which can cause compressor efficiency. Adversely affected gas leakage is minimized.

There are different types of refrigeration compressors, which vary depending on their configuration. Generally speaking, refrigeration compressors can be open, semi-hermetic, or hermetic. In a hermetically sealed compressor, the compressor and its drive motor are coupled to the same shaft and enclosed in a rigid, hermetically sealed housing. This type of hermetically sealed compressor is hermetically sealed and ensures that the working fluid does not leak to the outside. For example, they are generally used in a domestic refrigerator in a home, in a freezer, or in an air conditioner. The inside of the semi-hermetic compressor also contains a housing of the compressor and its drive motor; however, this housing can be opened to access both the motor and the compressor itself when repairs are needed. On the other hand, open compressors are configured without a compressor or motor housing, so they are non-leak-proof and easy to leak. They rely on shaft seals that require lubrication to prevent leakage of working fluid and maintain internal pressure. .

One of the main advantages of a hermetic compressor is that it is configured as a single unit and therefore can be easily transported due to its miniaturization. In addition, it is less noisy and its installation is very easy. However, repairs to this compressor are generally not expected, so when a problem occurs, the entire unit is replaced with a new compressor.

Compared with hermetic compressors, semi-hermetic compressors are easier to repair due to their accessibility. However, the occurrence of certain leaks results in some loss of compressor performance.

In both hermetic and semi-hermetic compressors, the electronics and wiring inside the housing are subject to very high temperatures due to being configured inside this hermetic housing, making these types of compressors expensive. In addition, if the windings are burnt, they may contaminate the entire system.

On the other hand, in an open configuration, in the event of a compressor or motor failure, it is easily accessible for repair, and maintenance is cheap and easy. Since the motors outside the enclosure operate under ambient conditions, it allows for a wider variety of motor choices and use of cheaper motor types. The disadvantage of this type of configuration is that these compressor types are noisy, not small, and there is a degree of gas leakage at the motor / chamber connection, which results in loss of motor performance. In addition, lubricating oil is required in the shaft seal so that the shaft seal maintains its sealing properties.

It would therefore be desirable to provide a compressor that has the advantages of open, hermetic, and semi-hermetic compressors while avoiding their disadvantages.

In the best current technology (eg document EP 2307734 B1), a rotary compressor arrangement with a rotating shaft is known, in which the motor structure is integrated inside the compressor arrangement. The overall structure is covered by an outer casing which hermetically seals both the motor and the compressor to form a hermetic compressor. This structure is small in size, but has the disadvantage that it cannot reach a high temperature inside the electronic component and cannot be properly cooled.

The compressor configuration according to the present invention provides a small, closed, quiet, and cost-effective solution: the compression chamber is in a sealed internal volume; the electronic components work externally and under ambient conditions, and more There is no direct physical connection between them, thus preventing any leakage.

According to a first aspect, the present invention relates to a rotary compressor arrangement 100, which includes a fixed member 40 and a rotary member 90, the fixed member is centered on an axis X, and the rotary member rotates around the fixed member 40 ; The fixed member 40 and the rotating member 90 are in one of the hermetically sealed internal volumes in the compressor configuration 100; the compressor configuration 100 includes a stator 210 having a winding configuration 211, and the winding configuration generates a With electromagnetic force, the stator 210 is arranged outside the sealed internal volume. The compressor configuration of the present invention further includes a plurality of magnets 221, which are directly attached to the rotating member 90 and face the winding configuration 211 in the stator 210, so that the rotating member 90 is warped by a rotating electromagnetic field from the stator 210. Belt rotation.

According to a preferred embodiment, the rotary compressor configuration 100 of the present invention further includes a rolling member 10 configured in an eccentric manner with respect to the fixed member 40 such that a chamber is established between the fixed member and the fixed member; the configuration 100 further Contains at least one satellite element 50, which is rotated by the belt through the rotating member 90; at least one satellite element 50 orbits at an offset axis Y and the belt rolling member 10 rotates and secures the fixed member 40 and the rolling member 10 contacts.

Preferably, the configuration of the rotary compressor of the present invention further includes an upper plate and a lower plate, and the upper plate and the lower plate are configured to be closed in a tight manner at a height and established between the fixed member 40 and the rolling member 10 At least one compression chamber 110.

Generally speaking, the rotary compressor configuration further includes at least one segment element disposed between the upper plate and / or the lower plate to allow the tight seal of the at least one compression chamber 110 and the movement of the rolling member 10. The at least one segment element 80 preferably includes a low-friction material.

In the rotary compressor configuration of the present invention, it is preferred that at least one pair of satellite elements 50, 50 'is arranged in the rotary member (90) in a height such that the magnet 221 is positioned between them.

Generally speaking, in the configuration of the rotary compressor of the present invention, the rotating member 90 is configured as a cylinder, and the magnet 221 is directly attached to an outer diameter circle of the rotating member.

Generally, these satellite components are mounted above a bearing 300 (preferably a ball bearing).

In the configuration of the rotary compressor of the present invention, the stator 210 generally includes a laminated magnetic core embedded in a resin material, and the stator 210 is an integral part of the motor housing 230.

According to a preferred embodiment, in the rotary compressor configuration of the present invention, the separation distance between the winding configuration 211 and the magnet 221 is as small as possible, generally less than about 1 mm.

The configuration of the rotary compressor of the present invention preferably further includes at least one sealed piston 30 that can slide inside the fixed member 40 during the rotation of the rolling member 10, thereby establishing at least one compression chamber 110 whose volume is borrowed It is reduced by the rotation of the rolling member 10 so that a compressible fluid, preferably a refrigerant gas, is compressed before being discharged.

Generally, in the rotary compressor configuration of the present invention, lubricating oil is also provided with the compressible fluid, which is compatible with the compressible fluid.

According to a second aspect, the invention relates to a cooling / freezing system comprising a rotary compressor arrangement 100 as previously described.

10‧‧‧Rotating member

30‧‧‧Sealed Piston

31‧‧‧Slot

40‧‧‧Fixed components

50‧‧‧ satellite components

50'‧‧‧ satellite element

50 "‧‧‧ satellite components

50 '' '‧‧‧Satellite element

90‧‧‧ rotating member

100‧‧‧ Rotary Compressor Configuration

110‧‧‧Sealed compression chamber

130‧‧‧fluid inlet

140‧‧‧fluid outlet

210‧‧‧ Stator

211‧‧‧winding configuration

221‧‧‧Magnet

230‧‧‧Motor housing

300‧‧‧bearing

Those skilled in the art will appreciate the further features, advantages, and objectives of the present invention when reading the following detailed description of the embodiments of the present invention in conjunction with the accompanying drawings.

FIG. 1 shows a schematic diagram of the main components in a compressor configuration with an integrated motor according to the present invention.

FIG. 2 shows an external view of a compressor configuration with an integrated motor according to the present invention as shown in FIG. 1. FIG.

FIG. 3 shows a schematic diagram of a motor stator and a motor magnet in a compressor configuration with an integrated motor according to the present invention.

FIG. 4 is a schematic diagram showing the arrangement of the stator, windings and rotating elements in a compressor configuration with an integrated motor according to the present invention.

FIG. 5 shows a cross-sectional view of a compressor configuration with an integrated motor according to the present invention.

Figure 6 shows a top view of a compressor arrangement with an integrated motor according to the present invention.

7a, 7b, and 7c respectively show an external configuration, a rotating element including a magnet, and a stator including a winding in a compressor configuration with an integrated motor according to the present invention.

8a, 8b, 8c, and 8d respectively show external configurations in a compressor configuration with an integrated motor according to the present invention; a rotating element including a magnet; a rolling element, a blade, and a fixed body; and a winding including Exploded view of the stator.

For example, as shown in FIG. 6, the present invention relates to a one-blade rotary compressor arrangement, which is hereinafter referred to as a rotary compressor arrangement 100 or simply a rotary compressor 100. The rotary compressor 100 of the present invention is preferably used in a cooling or freezing system, and the working fluid is generally any compressible gas, preferably a refrigerant gas or a mixture containing a refrigerant gas.

The rotary compressor 100 includes an inlet 130 and an outlet 140 through which working fluid enters the compressor, and once the fluid is compressed, it exits the mentioned compressor through the outlet.

In a preferred embodiment of the present invention, as can be seen in, for example, FIG. 8c, the compressor further includes a rolling member 10 with a fixed body 40 centered on an axis x. The compressor also includes a vane or sealed piston 30 that can slide into a slot 31 so as to contact the inner wall of the rolling member 10 and build a sealed compression chamber in which the compressed fluid is compressed, as will be described in more detail. Explainer. As shown in FIG. 8c, the fixed body 40 is disposed inside the rolling member 10 in an eccentric manner. Referring back to FIG. 6, the inlet 130 and the outlet 140 for the working fluid are disposed in the fixed body 40, and are preferably disposed adjacent to the sealing piston 30.

The configuration of the present invention is made so that the shaft (and the axis X) and the fixed body 40 are a single piece within the rotary compressor 100 and are static. However, rotating around the main body 40 is a rolling member 10 which, in fact, rolls over the outer surface of the fixed main body 40 which is belt-rotated via at least one satellite element 50, as will be explained further.

The sealing piston 30 is slidable in a slot 31 configured in the main body 40: during the entire rolling of the rolling member 10 around the fixed body 40, pressure is maintained in this slot 31 so that the sealing piston 30 contacts the rolling member 10. Inner wall. To achieve this, there is a tensioning device in the slot 31 that applies pressure above the sealing piston 30 so that the sealing piston contacts the inner wall of the rolling member 10: any kind of tensioning device (generally providing such functionality) can be used A spring), but a pneumatic device is also possible. In the configuration of the present invention, as shown in FIG. 6, the sealed piston 30 establishes a compression chamber 110 having a variable volume. More than one sealed piston may be used in different embodiments of the invention, thereby creating more than one compression chamber.

In the configuration of the rotary compressor of the present invention, the reference system is actually reversed: the main body 40 is fixed, and the rolling member 10 is at a pressure applied by the at least one satellite element 50 while rotating above it. Scroll above it.

The configuration of the present invention also includes at least one satellite element 50, which is mounted on a rotating member 90: by the rotation of the rotating member 90, the satellite element 50 is pushed above the rolling member 10 and rolls around the rolling member , Push the rolling member toward the fixed body 40. Therefore, when the rotating member rotates around the rolling member 10, there is always a contact between the rolling member 10 and the main body 40 (in general, when the fixed main body 40 and the rolling member 10 have a cylindrical shape, there is a longitudinal contact line ). It is also obvious that this contact is aligned with the position of the satellite element 50. A sealed compression chamber 110 having a variable volume (decreased with time) is established by the sealing piston 30 contacting the inner wall of the rolling member 10, and the working fluid is compressed therein before being discharged.

The satellite element is configured to be offset from the axis X, and is located at, for example, one axis Y shown in FIG. 5, and the satellite element is orbited about 40 rows of the fixed body. The satellite element 50 contacts the outer wall of the rolling member 10 under a certain pressure or force (that is, the distance between the axis X and the axis Y such that this force is applied and maintained during the entire orbital motion of the satellite element): as explained previously The contact between the satellite element 50 and the outer wall of the rolling member 10 under pressure causes the satellite element 50 to rotate with the rolling member 10 above the fixed body 40 (actually rolling), similar to a gear configuration.

When, for example, FIG. 7b or FIG. 8b is viewed, a pair of satellite elements 50 and 50 'are (for example) arranged at a certain height, pressed against the outer wall of the rolling member 10, and fixed to one of the fixed body 40 and the rolling member 10. Internal contact alignment. These drawings also represent, for example, another pair of satellite elements 50 "and 50 '", which are arranged in height and also press above the outer wall of the rolling member 10: In this configuration, within the rolling member 10 The wall contacts the fixed body 40 at an intermediate point between the external contacts of the paired satellite elements 50, 50 'and 50 ", 50'".

The satellite element is generally mounted above a bearing 300 (preferably a ball bearing), as shown in, for example, FIG. 1 or FIG. 4.

Generally speaking, the compressor of the present invention is configured to work with a refrigerant gas as a working fluid, and the oil is also taken into the compressor together with the refrigerant to lubricate the moving parts and seal the parts between the parts. Clearance or clearance. It is preferred to introduce the oil into the compressor by an oil pump (not shown), and generally a device (not shown) is also provided to collect the oil and return the oil to the oil pump, so that once again with refrigeration Pump together with the pump oil. Lubricating oil can be any oil compatible with the refrigerant used as the working fluid in the compressor. The refrigerant may be any suitable refrigerant effective over a given temperature range of interest.

Generally speaking, the compressor configuration of the present invention also includes an upper plate and a lower plate, which close the upper and lower portions of the compressor, thereby sealing the compression chamber 110 established with the sealing piston 30. The distance between the two plates and the height of the main body configuring the rolling member 10 must be accurate in order to properly seal and establish the compression chamber 110, but certain clearance adjustments or compensations can be implemented to act on the satellite (s). Component. However, other components that configure the compressor configuration of the present invention need not be completed with exact tolerances as known in the prior art, which makes this configuration easier to manufacture and therefore less expensive. Generally speaking, at least one segment element is further disposed between the upper plate and / or the lower plate to allow a tight seal of the compression chamber 110 while allowing the rolling member 10 to move. This configuration is made so that the movement of the rolling member 10 relative to the fixed body 40 and the plates has low friction. Preferably, the material for configuring the segment element is a low-friction material, typically Teflon ^® .

These low-friction materials generally allow long-lasting solutions in applications that require sliding action of parts but still have low maintenance requirements. The friction characteristics of a material are generally given by the coefficient of friction, which is given a value that shows that when an object moves across a surface made of such a material, it makes the object between the object and the surface. There is a relative motion of the force exerted by the surface. Generally speaking, for Teflon, this friction coefficient is included between 0.04 and 0.2. The low friction material has a coefficient of friction below 0.4, more preferably below 0.3, and even more preferably below 0.2.

The object of the present invention is to integrate the drive motor structure into the configuration of a rotary vane compressor itself. This motor integration according to the present invention can be accomplished in a compressor configuration having a fixed axis (or the fixed body 40 connected to the same axis X) and an external rotating member (in this case, an external rotating member 90). In a preferred embodiment of the present invention, the configuration of the compressor configuration 100 includes satellite elements, which are mounted in the rotating member 90 and push the rolling member 10 on the fixed body 40, as discussed. The winding 211 is mounted on an external stator 210, and the magnet 221 is directly attached to the outer surface of the rotating member 90, directly facing these windings 211, and no metal element is arranged between the magnet and the winding. The distance between the magnet and the winding should be free and as small as possible, generally less than about 1mm; otherwise the efficiency will drop and it will not be possible to rotate the rotor.

When a current is circulated through the winding 211, an electromagnetic force or an electromagnetic field is generated in the stator 210: these windings work as electromagnets and therefore have poles, the opposite of which are in the magnet 221 directly attached to the rotating member 90. The magnetic field generated between these poles is designed to orient and generate a force to provide a torque in the rotating member 90 to cause it to rotate.

It is obvious that in conventional rotary compressors, this type of configuration for windings and magnets would not be feasible, as there are no attachable magnets and direct windings in the rotor (without any metal components inserted ) External rotating element. The configuration of the present invention is particularly advantageous because it integrates the rotor of the compressor (the rotating part of the compressor configuration, the rotating member 90) and the rotor of the motor (that is, where the permanent magnet is located) into a single element, thereby Provide a small closed solution. In addition, the stator windings are arranged externally, and the windings can be advantageously cooled compared to a closed solution in which the windings are inside a closed room. The hermetically sealed chamber in the configuration 100 of the present invention groups the main body 40, the rolling member 10, the rotating element 90, and the magnet 221 therein, as shown, for example, in FIG. The stator 210 together with the windings 211 can thus be arranged outside this enclosed room and can be easily cooled, as shown in, for example, any one of FIG. 1 or FIG. 2.

The stator 210 in the configuration of the present invention generally includes a laminated magnetic core embedded in a resin, which is configured as an integral part of the motor housing (the stator 210 constitutes a vertical part of the motor housing). Laminated magnetic cores generally include a plurality of thin metal sheets, which are substantially parallel to the flux line, so that the magnetic core is equivalent to many individual magnetic circuits, each of which receives a small portion of the magnetic flux, thereby greatly limiting most Vortex flow.

In general, the configuration of the present invention proposes to use the rotating parts of the compressor to be used and the motor rotor. This allows the rotating component to be driven directly, which greatly reduces the number of components and noise. The final configuration of the compressor configuration is very robust and small, and can withstand a pressure of 20 bar, maintaining a seal against the refrigerant gas used. Furthermore, this arrangement is extremely small by using a bearing on which a rotating member is mounted. Also, since the stator is in direct contact with the outside air, heat dissipation from the stator is improved. The rigid structure of the magnetic circuit integrated in the compressor configuration thus contributes to the mechanical resistance of the motor housing.

Referring now to the attached drawings, FIG. 1 shows the configuration of the fixed body 40 surrounded by the rolling member 10 in an eccentric manner, and the rolling member is rolled on the outer wall of the main body 40 via the rotating member 90 mounted on the bearing 300. The magnet 221 is directly attached to the outer wall of the rotating member 90 and faces the corresponding winding 211 in the stator 210. However, the general laminated structure of the stator is not depicted in this figure.

FIG. 2 shows the entire compressor configuration 100 as seen from the outside as a complete small structure with a motor housing 230 on the outside, showing the stator 210 with the windings 211 hidden therein. FIG. 3 shows where the windings are located inside the stator 210 and how they face the (floating view) magnet 221.

FIG. 4 shows where the satellite element will be arranged in the compressor and mounted on the rotating member 90.

FIG. 5 shows a cross-sectional view of a compressor configuration according to a preferred embodiment of the present invention, which shows a grouping magnet 221, a rotating member 90, a rolling member 10, and a fixed body 40 inside an enclosed room. The stator 210 with the windings 211 is arranged outside the closed room.

FIG. 6 shows the structure of a rotary vane compressor having a fluid inlet 130 and a fluid outlet 140 for the fluid once the fluid has been compressed. It shows a sealing piston 30 which can be slid into a slot 31 to contact the inner wall of the rolling member 10 and a sealed compression chamber 110 established in which the fluid is compressed before the fluid is discharged through the outlet 140. Shown are two satellite elements 50 and 50 ", which push the rolling member 10 on the fixed body 40 to change the volume of the chamber 110. Here it can be seen how the inner wall of the rolling member 10 contacts the outer wall of the fixed body 40 Occurs at an intermediate angular position between the satellite elements 50 and 50 "and the external contact of the rolling member 10.

7a, 7b, and 7c show a motor housing 230 (FIG. 7a) having a stator 210; a rotating member 90 having an externally attached magnet 221, and a pair of satellite elements 50, 50 'and another pair of satellite elements How to arrange 50 ", 50 '" in this member 90 according to height so that rolling member 10 is pushed and rolled (Figure 7b); stator configuration 210 with windings 211, which windings will face magnet 221 (Figure 7c) .

8a, 8b, 8c, and 8d show a motor housing 230 (FIG. 8a) with a stator 210; a rotating member 90 with a magnet 221 attached to the outside, and a pair of satellite elements 50, 50 'and another How to arrange the satellite elements 50 ", 50 '" in height in this member 90 so that the rolling member 10 is pushed and rolled and the magnet 221 is arranged between these satellite elements (Fig. 8b); The rolling member 10 on the main body 30 and the sealed piston 30 (FIG. 8c) contacting its inner wall; a stator configuration 210 with windings 211, which windings will face the magnet 221 (FIG. 8d).

Although the present invention has been described with reference to preferred embodiments, those skilled in the art can implement many modifications and changes without departing from the scope of the present invention as defined by the scope of the appended patents.

Claims (12)

    A rotary compressor arrangement (100) includes a fixed member (40) and a rotary member (90), the fixed member (40) is centered on an axis (X), and the rotary member (90) surrounds the The fixed member (40) rotates; the fixed member (40) and the rotating member (90) are inside a sealed internal volume of the compressor configuration (100); the compressor configuration (100) includes a One of the stators (210) of the winding arrangement (211), the winding arrangement (211) generates an electromagnetic force inside the stator (210), the stator (210) is arranged outside the sealed internal volume; the compression The machine configuration (100) further includes a plurality of magnets (221), which are directly attached to the rotating member (90) and face the winding configuration (211) in the stator (210) such that the The rotating member (90) is rotated through the reel by a rotating electromagnetic field from the stator (210).         For example, the rotary compressor configuration (100) of claim 1, further comprising a rolling member (10), the rolling member (10) is arranged in an eccentric manner with respect to the fixed member (40), so that the rolling member ( 10) A chamber is established between the fixed member (40); the configuration (100) further includes at least one satellite element (50), and the at least one satellite element (50) is warped by the rotating member (90) Belt rotation; the at least one satellite element (50) orbits at an offset axis (Y), and the belt rotates the rolling member (10) and ensures that the fixed member (40) and the rolling member (10) One touch.         The rotary compressor configuration (100) according to any one of the preceding claims, further comprising an upper plate and a lower plate, the upper plate and the lower plate being configured to be closed to the fixed member in a tight manner and at a height. (40) At least one compression chamber (110) established between the rolling member (10).         The rotary compressor arrangement (100) of claim 3, further comprising at least one segment element disposed between the upper plate and / or the lower plate to allow one of the at least one compression chamber (110) to be tightly sealed and The movement of the rolling member (10).         For example, the rotary compressor configuration (100) of any one of claims 2 to 4, wherein at least a pair of satellite elements (50, 50 ') are arranged in the rotary member (90) in a height, so that the magnets (221 ) Is positioned between the at least one pair of satellite elements (50, 50 ').         If the rotary compressor configuration (100) of claim 5, wherein the rotary member (90) is configured as a cylinder, the magnets (221) are directly attached to an outer diameter circle of the rotary member (90) in.         The rotary compressor configuration (100) according to any one of claims 2 to 6, wherein the satellite elements are mounted on a bearing (300), preferably a ball bearing.         The rotary compressor configuration (100) according to any one of the preceding claims, wherein the stator (210) includes a laminated magnetic core embedded in a resin material, and the stator (210) is the motor housing (230) An integral part of it.         The rotary compressor configuration (100) as in any one of the preceding claims, wherein the distance separating the winding configuration (211) from the magnets (221) is as small as possible, generally less than about 1 mm.         The rotary compressor arrangement (100) according to any one of the preceding claims, further comprising at least one sealing piston (30), the sealing piston (30) being accessible to the fixed member during rotation of the rolling member (10) (40) slides inside to establish at least one compression chamber (110), the volume of which is reduced by the rotation of the rolling member (10), so that a compressible fluid is preferably A refrigerant gas is compressed before being discharged.         The rotary compressor configuration (100) of claim 10, wherein a lubricating oil is also provided with the compressible fluid, and the lubricating oil is compatible with the compressible fluid.         A cooling / freezing system comprising a rotary compressor arrangement (100) as claimed in any one of claims 1 to 11.