Scroll compressor

Abstract

Scroll compressor with a stationary, stator scroll and a movable rotor scroll and a drive to move the rotor, whereby in each position places are formed with an instantaneous minimum opening between the rotor scroll and the stator scroll whereby at each height in a minimum opening there is a local transverse internal clearance (S), whereby at least one of the stator flanks or rotor flanks comprises an adapted flank section with an initial local stator flank deviation (T.sub.0i, AT.sub.0u) or rotor flank deviation (R.sub.0i/AR.sub.0u) that is different to zero at each point when the rotor is stationary, and during nominal operation of the scroll compressor corresponding instantaneous final local stator flank deviations (T.sub.fi, T.sub.fu) or rotor flank deviations (R.sub.fi, R.sub.fU) whose absolute values are smaller.

Claims

1. A scroll compressor comprising a stationary stator scroll and a movable rotor scroll, each with a central axis, whereby said stator scroll and said rotor scroll are formed by a strip that is wound spirally along a length and which is affixed upright with a certain height on a stator plate or a rotor plate respectively, whereby each strip has two flanks, whereby intersecting lines of the flanks with the stator plate or the rotor plate concerned form spiral base edges, whereby a geometric location of points through which a perpendicular line on the stator plate intersects in an aforementioned spiral base edge determine ideal spiral flanks, whereby a radial distance between a point on the flank of the rotor scroll or the stator scroll and a closest ideal spiral flank defines a local flank deviation, respectively, a local stator flank deviation or a local rotor flank deviation, whereby the scroll compressor comprises a drive to move a rotor whereby a central axis of the rotor circles eccentrically around the central axis of the stator scroll without the rotor hereby undergoing a rotation around its central axis, whereby in each position of the rotor in a stator during this circling and eccentric movement of the rotor, places are formed to have either a maximum opening or a minimum opening between the rotor scroll and the stator scroll, whereby the places that have the maximum or the minimum opening are located in a facing plane; the facing plane comprises both aforementioned central axes, whereby in the places with the minimum opening at each local height with respect to the stator plate, the rotor flank and the stator flank concerned are located at a certain radial distance from one another, wherein the radial distances form local transverse internal clearances, whereby during a transition from an initial stationary state of the rotor to a final state in nominal service, pressures and temperatures in the scroll compressor change resulting in a deformation of the stator scroll and the rotor scroll and a change of the local stator flank deviations and the local rotor flank deviations, as well as the local transverse internal clearances, wherein at least one of the stator flanks or the rotor flanks comprises an adapted flank section whose form is initially adapted by having a local initial rotor flank deviation or a local initial stator deviation that is different to zero at each point of the adapted flank section concerned in the initial stationary state of the scroll compressor, whereby upon the transition of the scroll compressor from the initial stationary state to the final state in nominal service, the stator scroll and the rotor scroll deform such that during the movement of the rotor in nominal service there is an instantaneous final local stator flank deviation or an instantaneous final local rotor flank deviation at each point of the aforementioned adapted flank section concerned and in each position of the rotor, whose absolute value is less than the corresponding local initial stator flank deviation or the local initial rotor flank deviation at the same point when the rotor is stationary.

2. Scroll compressor according to claim 1, wherein at least one of the stator flanks or rotor flanks in its entirety forms an aforementioned adapted flank section.

3. Scroll compressor according to claim 1, wherein more than one of the stator flanks or rotor flanks in its entirety forms an aforementioned adapted flank section.

4. Scroll compressor according to claim 1, wherein the stator scroll and the rotor scroll are each provided with an aforementioned adapted flank section.

5. Scroll compressor according to claim 4, wherein the stator scroll and the rotor scroll have an inward stator flank or an inward rotor flank respectively that is turned towards the centre of the scroll compressor and an outward stator flank or an outward rotor flank respectively that is turned away from the centre of the scroll compressor and whereby the outward stator flank and the outward rotor flank are provided with the aforementioned adapted flank sections.

6. Scroll compressor according to claim 1, wherein for at least some of the positions occupied by the rotor during its movement, the local transverse internal clearances over the height of the stator flank concerned and rotor flank are constant during nominal service, so that these local transverse internal clearances over the height have a variation equal to zero in the positions concerned.

7. Scroll compressor according to claim 6, wherein for all positions occupied by the rotor during its movement, the local transverse internal clearances over the height of the stator flank and rotor flank concerned are constant during nominal service, so that the local transverse internal clearances over the height have a variation equal to zero in all positions occupied by the rotor.

8. Scroll compressor according to claim 1, wherein the stator scroll is profiled such that when the scroll compressor is stationary, an aforementioned adapted flank section of a stator flank presents a certain setback from the stator base formed by the edge of the stator strip at the stator plate up to the stator tip formed by a free edge of the stator strip or whereby this adapted flank section of the stator flank presents a certain inclination with respect to the stator plate, while an opposite flank section at the other flank of the stator scroll is made flat when stationary and is in a perpendicular position on the stator plate, so that the stator scroll has a thickness that is greater at the stator base than at the stator tip.

9. Scroll compressor according to claim 1, wherein the rotor scroll is profiled such that when the scroll compressor is stationary, an aforementioned adapted flank section of a rotor flank presents a certain setback from the rotor base formed by the edge of the rotor strip at the rotor plate up to the rotor tip formed by a free edge of the rotor strip, or whereby this adapted flank section of the rotor flank presents a certain inclination with respect to the rotor plate, while an opposite flank section at the other flank of the rotor scroll when stationary is made flat and is in a perpendicular position on the rotor plate, so that the rotor scroll has a thickness that is greater at the rotor base than at the rotor tip.

10. Scroll compressor according to claim 8, wherein the stator scroll and the rotor scroll have an inward stator flank or an inward rotor flank respectively that is turned towards the centre of the scroll compressor and an outward stator flank or an outward rotor flank respectively that is turned away from the centre of the scroll compressor, whereby the aforementioned adapted flank section of the stator flank with a setback or inclination forms part of the outward stator flank, and the aforementioned adapted section of the rotor flank with setback or inclination forms part of the outward rotor flank.

11. Scroll compressor according to claim 1, wherein the rotor scroll or the stator scroll is constructed with rotor flanks or stator flanks respectively that are both, when the scroll compressor is stationary, perpendicular on the rotor plate or the stator plate respectively.

12. Scroll compressor according to claim 1, wherein the rotor scroll or the stator scroll is constructed with rotor flanks or stator flanks respectively that, when the scroll compressor is stationary, both present a certain setback or inclination with respect to the rotor plate or the stator plate respectively, whereby the flanks concerned in their entirety form the aforementioned adapted flank sections.

13. Scroll compressor according to claim 1, wherein the adapted flank section of a stator flank or a rotor flank when stationary presents a certain setback or inclination, whereby this adapted flank section during nominal service is perpendicular to the stator plate concerned or the rotor plate concerned.

14. Scroll compressor according to claim 1, wherein the adapted flank section of a stator flank or a rotor flank presents a certain setback or inclination whereby the adapted flank section concerned has a continuous profile.

15. Scroll compressor according to claim 1, wherein the adapted flank section of a stator flank or a rotor flank presents a certain setback or inclination and the adapted flank section concerned has a discontinuous profile, whereby the thickness of the stator scroll or the thickness of the rotor scroll with the adapted flank section concerned decreases stepwise.

16. Scroll compressor according to claim 15, wherein in the adapted flank section of the stator flank or the rotor flank with a discontinuous profile, the thickness of the adapted flank section concerned of the stator scroll or the rotor scroll has one step change over its height.

17. Scroll compressor according to claim 15, wherein in the adapted flank section of the stator flank or the rotor flank with a discontinuous profile, the thickness of the adapted flank section concerned of the stator scroll or the rotor scroll has a number of step changes over its height.

18. Scroll compressor according to claim 1, wherein the scroll compressor is an oil-free scroll compressor.

19. Scroll compressor according to claim 2, wherein more than one of the stator flanks or rotor flanks in its entirety forms an aforementioned adapted flank section.

20. Scroll compressor according to claim 9, wherein the stator scroll and the rotor scroll have an inward stator flank or an inward rotor flank respectively that is turned towards the centre of the scroll compressor and an outward stator flank or an outward rotor flank respectively that is turned away from the centre of the scroll compressor, whereby the aforementioned adapted flank section of the stator flank with a setback or inclination forms part of the outward stator flank, and the aforementioned adapted section of the rotor flank with setback or inclination forms part of the outward rotor flank.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) With the intention of better showing the characteristics of the invention, a few preferred embodiments of a scroll compressor according to the invention are described hereinafter by way of an example, without any limiting nature, with reference to the accompanying drawings, wherein:

(2) FIGS. 1 and 2 shows an exploded view in perspective of a scroll compressor, respectively from two opposite points of view;

(3) FIG. 3 shows a cross-section through the scroll compressor of FIGS. 1 and 2 in an assembled state;

(4) FIGS. 4 to 7 schematically show a cross-section through an assembled scroll compressor, to illustrate the operation of a scroll compressor, parallel to the line XX in FIG. 3 corresponding to the stator plate, whereby the rotor scroll is in successive positions with respect to the stator scroll;

(5) FIGS. 8 to 11 schematically show cross-sections through a known scroll compressor, with some exaggeration of the internal clearances, according to the lines VIII-VIII to XI-XI designated in FIGS. 4 to 7;

(6) FIGS. 12 and 13 show an enlargement of the section designated by F12/F13 in FIG. 8, respectively of a stationary known scroll compressor and a known scroll compressor in nominal service;

(7) FIGS. 14 and 15 also show an enlargement of the section designated by F14/F15 in FIG. 10, respectively of a stationary known scroll compressor and a known scroll compressor in full service;

(8) FIGS. 16 to 19, analogous to FIGS. 12 to 15, illustrate the deformation of the stator scroll and rotor scroll in a transition from a stationary state to nominal service in a first embodiment of a scroll compressor according to the invention;

(9) FIGS. 20 to 23, FIGS. 24 to 27, FIGS. 28 to 31 and FIGS. 32 to 35, analogous to FIGS. 16 to 19, each time show the different respective states for other embodiments of a scroll compressor according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

(10) The elements shown in FIGS. 1 to 3 present an oil-free scroll compressor 1 in an expanded and assembled state and of a type to which the invention relates.

(11) This scroll compressor 1 has a housing 2, which in this case is essentially composed of two sections, more specifically section 3 and section 4, which in the assembled state enclose a space 5 in which a rotor 6 is affixed.

(12) Moreover, the section 3 forms a stator 7 that is affixed immovably in the housing 2 and which comprises a stationary stator scroll with a central stator axis AA.

(13) This stator scroll 8 is formed by a stator strip 9 with two stator flanks 10 and 11, respectively an outward stator flank 10 that is turned away from the centre or the central axis AA of the stator scroll 8, and an inward stator flank 11 that is turned towards the centre or towards the central axis AA of the stator scroll 8.

(14) Moreover, the stator strip 9 is wound spirally along its length and affixed upright with a certain height H on a first side 12 of a stator plate 13.

(15) Cooling fins 15 are provided on the other side 14 of the stator plate 13.

(16) The rotor 6 can be moved in the housing 2 and has a rotor scroll 16 with a central rotor axis BB, which extends parallel to the central axis AA of the stator 7, at a certain distance E from it.

(17) The rotor scroll 16 is formed by a rotor strip 17 with two rotor flanks 18 and 19, respectively an outward rotor flank 18 that is turned away from the centre or from the central axis BB of the rotor scroll 16, and an inward rotor flank 19 that is turned towards the centre or towards the central axis AA of the rotor scroll 16.

(18) Moreover, the rotor strip 17 is wound spirally along its length and affixed upright with a certain height H to a first side 20 of a rotor plate 21.

(19) Cooling fins 23 are also provided on the other side 22 of the rotor plate 21, just as with the stator 7.

(20) In the assembled state of the scroll compressor 1 the rotor scroll 16 and the stator scroll 8 are affixed in one another between the stator plate 13 and the rotor plate 21 in order to be able to work together to compress air or possibly another gas.

(21) The scroll compressor 1 is further provided with a low pressure inlet 24 on the outside 25 of the scroll compressor 1 to draw in ambient air or gas, as well as with a high pressure outlet 26 at the centre 27 of the scroll compressor 1 to remove compressed air or gas.

(22) In order to be able to drive the rotor 6 the scroll compressor 1 is further provided with a drive that is such that the rotor 6 can make a movement, whereby the central rotor axis BB circles eccentrically around the central stator axis AA, more specifically over a circle C with a radius R, which aside from a clearance, is practically equal to the distance E between the central rotor axis BB and the central stator axis AA, which is shown more clearly in FIGS. 4 to 11.

(23) As is known, during its motion the rotor 6 does not undergo a rotation around the central rotor axis BB.

(24) The movement of the rotor 6 in the stator 7 is illustrated in FIGS. 4 to 7, whereby in each subsequent drawing the central axis BB is moved a quarter stroke further over the circle C.

(25) This clearly shows that in each position of the rotor 6 in the stator 7 during this circling and eccentric movement of the rotor 6, places 28 are formed where there is a maximum opening 28 and places 29 where there is a minimum opening 29 between the rotor scroll 16 and the stator scroll 18.

(26) It is also clear that those places with a minimum opening and maximum opening 28 lie in the plane MM at all times, which comprises the parallel central axes AA and BB of the stator scroll 8 and the rotor scroll 16 respectively.

(27) As set out in the introduction, this plane MM is designated in this text by the name sealing plane MM.

(28) It can be seen from FIGS. 4 and 6 and the accompanying cross-sections shown in FIGS. 8 and 10 that in a complete circular movement of the central rotor axis BB around the central stator axis AA, there are two positions each time whereby the places with a minimum opening 29 and maximum opening 28 are in the same sealing plane MM.

(29) These two positions of the central rotor axis BB are more specifically a first position whereby the central rotor axis BB is in a first position with respect to the central stator axis AA, and a second position whereby the central rotor axis BB is in a second position with respect to the central stator axis AA that is diametrically opposite its first position.

(30) Similar diametrical positions of the central rotor axis BB are shown in FIGS. 5 and 7 and the accompanying cross-sections are also shown in FIGS. 8 and 10 respectively.

(31) Upon further examination it is also the case that in the one aforementioned position of the rotor 6 the minimum openings 29 are formed between an outward stator flank 10 and an inward rotor flank 19, as is the case for example in the positions of the rotor 6 in the stator 7, shown in FIGS. 4, 5 and 8, while in the second diametrical position of the rotor 6 in the stator 7, the minimum openings 29 are precisely reversed and are formed between an inward stator flank 11 and an outward rotor flank 18, such as is the case for example in the positions of the rotor 6 in the stator 7 shown in FIGS. 6, 7 and 10.

(32) Hereby it is indeed also the case that the same sections of the rotor scroll 16 or the stator scroll 8 concerned are those that determine the minimum openings 29 in both diametrical positions, so that each deformation of the stator scroll 8 or the rotor scroll 16 has increasing effects on the size of the minimum openings 29, whereby furthermore these deformations in the two diametrical positions of the rotor 6 in the stator 7 result in opposite local effects, as will be illustrated further.

(33) It is the places with a minimum opening 29 that define a compression chamber 30 in each case, whereby these compression chambers 30 decrease in volume towards the centre 27 of the scroll compressor 1.

(34) The size of these minimum openings 29 is thus of great importance, as on the one hand there always has to be a minimum clearance in the scroll compressor in order to prevent contact between the stator scroll 8 and the rotor scroll 16, and on the other hand too large an instantaneous minimum opening 29 is coupled with large compression losses and leakage rates between successive compression chambers 30.

(35) In such an instantaneous minimum opening at each local height Z with respect to the stator plate 13, the outward rotor flank 18 concerned and the inward stator flank 11 concerned, or the inward rotor flank 19 concerned and the outward stator flank 10 concerned are located at a certain radial distance S from one another.

(36) Radial here means that the distance in the instantaneous sealing plane MM is measured radially from one of the central axes AA or BB parallel to the stator plate 13 or the rotor plate 21.

(37) These radial distances S define instantaneous local transverse internal clearances S during the movement of the rotor 6 at each moment, i.e. at each instantaneous position of the rotor 6 in the stator 7, as well as at each height Z.

(38) In each position of the rotor 6 in the stator 7 there are different pairs of points on the flanks 10, 11, 18 and 19, of the stator scroll 8 and the rotor scroll 16 respectively, which in each case form an instantaneous local transverse internal clearance S in an instantaneous sealing plane MM.

(39) When going from an initial state of the stationary rotor 6 to a final state during nominal service of the scroll compressor 1, the pressures and temperatures in the scroll compressor 1 change significantly resulting in a deformation of the stator scroll 8 and the rotor scroll 16.

(40) It is clear that such deformations of the stator scroll 8 and the rotor scroll 16 have an enormous effect on the instantaneous local transverse clearances S in the instantaneous minimum openings 29 of the scroll compressor 1.

(41) According to the invention it is also the case that these deformations are best evaluated beforehand in order to give an initial form to the stator scroll 8 and/or the rotor scroll 16, which after deformation results in a desired or at least improved instantaneous final local transverse internal clearance S, compared to the situation in which no measure is taken, as is the case with the known scroll compressors 1.

(42) Ideally, as an alternative or additionally, measures can be taken in order to counteract the deformations that relate to a change of the instantaneous final local internal transverse clearances S in the scroll compressor 1, for example by using an adapted composition of materials.

(43) In order to clearly specify the initial forms when the scroll compressor 1 is stationary and the later deformations during the transition to the nominal operation of the scroll compressor 1, use will be made of terminology specified hereinafter, which moreover must be stripped of any possible intuitive or interpretive meanings.

(44) First and foremost, it is assumed that both with the known scroll compressors and the scroll compressors 1 according to the invention, the intersecting lines 31 of the flanks 10, 11, 18 and 19 of the stator scroll 8 and rotor scroll 16 respectively with the stator plate 13 or the rotor plate 21 concerned, form spiral-shaped base edges 31.

(45) These base edges 31 will be used as a reference to define the form of the stator scroll 8 and the rotor scroll 16, whereby it is pointed out that these base edges 31 are not static objects in practice.

(46) Indeed, the absolute position of these base edges 31 with respect to an ideal fixed axis system will change due to a change of temperature in the stator plate 13 and the rotor plate 21 during a transition from the stationary scroll compressor 1 to the nominal operation of the scroll compressor 1, whereby this change must be taken into account in the further considerations.

(47) Furthermore, the geometric location of the points through which a perpendicular line on the stator plate 13 intersects in an aforementioned spiral base edge 31 determines ideal spiral flanks 32.

(48) In brief, the ideal spiral flanks 32 are flanks of the stator scroll 8 and the rotor scroll 16 devoid of any physical reality, which in all circumstances are perpendicular to the stator plate 13 or rotor plate 21 starting from the base edges 31, and these spiral flanks 32 would be ideal in the sense that the local transverse internal clearances S at the very least do not present any variation over the height with respect to the stator plate 13 or rotor plate 21 in all circumstances.

(49) The radial distance R between a point on a flank 18 or 19 of the rotor scroll 16 at a height Z with respect to the stator plate 13 and the closest ideal spiral flank 32 determines a local form of the rotor scroll 16, which hereinafter will be designated as the local rotor flank deviation R.

(50) In the same way the radial distance T between a point on a flank 10 or 11 of the stator scroll 8 and the closest ideal spiral flank 32 at a height Z with respect to the stator plate 13 determines a local form of the stator scroll 8, which hereinafter will be designated as a local stator flank deviation T.

(51) FIG. 12 shows, with a certain exaggeration of the clearances concerned, an enlargement of a section through a known scroll compressor 1 in a sealing plane MM when the scroll compressor 1 is stationary, in a position of the rotor 6 in the stator 7, as shown for example in FIGS. 4 and 5.

(52) Completely analogously, with a certain exaggeration of the clearances concerned, FIG. 14 shows an enlargement of a section through a known scroll compressor 1 in the same sealing plane MM when the scroll compressor 1 is stationary, in the diametrically opposite position of the rotor 6 in the stator 7, as shown in FIGS. 6 and 7 for example.

(53) If the forms of the stator scroll 8 and the rotor scroll 16 when stationary are designated with the subscript 0 and at nominal operation with the subscript f, then the following can be said.

(54) With known scroll compressors 1 in the initial state when the scroll compressor 1 is stationary, irrespective of the position of the rotor 6 in the stator 7, or thus irrespective of the sealing plane MM, there is no local rotor flank deviation R.sub.0 and no local stator flank deviation T.sub.0, or there is thus a local rotor flank deviation R.sub.0 or a local stator flank deviation T.sub.0 equal to zero, and this at every height Z, Z, Z, etc, with respect to the stator plate 13.

(55) Indeed, the known scroll compressors 1 are constructed with a stator scroll 8 and rotor scroll 16 that initially, when the scroll compressor is stationary, at least approximately have ideal spiral flanks 32.

(56) A first consequence of this is that in principle there is no initial clearance deviation S.sub.0 in the known scroll compressors 1.

(57) A further consequence of this is also that the local transverse internal clearance S at each height Z, Z, Z, etc, in a sealing plane MM is initially constant in such known scroll compressors 1 and is equal to a basic clearance W, which is defined by the radial distance W in the instantaneous sealing plane MM concerned between the ideal spiral flanks 32, which are located closest to the flanks 11 and 18 or 10 and 19 concerned.

(58) Thus there is no initial variation of the initial clearance profile over the height Z in the known scroll compressors 1 in the instantaneous minimum openings 29 when the scroll compressor 1 is stationary.

(59) During a transition from this stationary state to the nominal operation of the known scroll compressor 1, deformations occur of which typical cases are shown in FIGS. 13 and 15 by way of illustration.

(60) As set out in the introduction, the rotor tips 33 and the stator tips 34 tend to deviate towards the outside 25 of the scroll compressor 1, because the pressures, as well as the temperatures, in the scroll compressor 1 increase towards the centre 27 and because a temperature gradient prevails in the height direction Z with an increasing temperature from a rotor base 35 to a rotor tip 33, as well as from a stator base 36 to a stator tip 34.

(61) Depending on the position of the rotor 6 in the stator 7 this leads to opposite phenomena with regard to the final profile of the local transverse internal clearance S.sub.f over the height Z of the scrolls 8 and 16.

(62) FIGS. 13 and 15 clearly show that at each height Z, Z, Z, etc, in an instantaneous sealing plane MM there is a different instantaneous local transverse internal clearance S that consists of the interjacent instantaneous basic clearance W and an instantaneous local clearance deviation S.

(63) In brief each local transverse internal clearance S can be described as the sum of a desired instantaneous ideal basic clearance W and a local clearance deviation S that is due to local deviations of the rotor scroll 16 and the stator scroll 8.

(64) At each height Z, Z, Z, etc, the instantaneous local clearance deviation S is the difference between a local instantaneous rotor flank deviation R and a local instantaneous stator flank deviation T, whereby the principle is that deviations of the stator scroll 8 and the rotor scroll 16 of the same orientation have the same sign, more specifically a positive or negative sign depending on whether the deviation (from a point on the ideal spiral flank to the spiral flank) is towards the outside 25 or towards the centre 27 of the scroll compressor 1, and as a result it does not yield any clearance deviation S if they are of the same magnitude.

(65) In FIGS. 12 to 15, the stator scroll 8 and the rotor scroll 16 are constructed with parallel flanks or with a constant thickness, such that a stator flank deviation Tu of the outward stator flank 10 is always coupled with a stator flank deviation Ti of the inward stator flank 11 of the same magnitude and such that a rotor flank deviation Ru of the outward rotor flank 18 is always coupled with a rotor flank deviation Ri of the inward rotor flank 19 of the same magnitude.

(66) In the case of FIG. 13 during nominal service of the scroll compressor, the instantaneous local transverse internal clearance S is formed by the distances concerned between the external rotor flank 18 and the internal stator flank 11.

(67) Hereby the rotor tips 33 bend in the instantaneous sealing plane MM concerned towards the opposite stator bases 36, such that the instantaneous local transverse internal clearance S at the rotor tips 33 decreases with respect to the basic clearance W, while the stator tips 34 bend away from the opposite rotor bases 35 such that the local internal clearance S at the stator tips 34 increases with respect to the basic clearance W.

(68) At each height Z the instantaneous local stator flank deviation T.sub.fi concerned makes an instantaneous final contribution to the instantaneous final clearance deviation S.sub.f that increases the instantaneous final clearance S.sub.f, while the instantaneous final local rotor flank deviation R.sub.fu makes a contribution to the instantaneous final clearance deviation S.sub.f that decreases the local transverse internal clearance S.sub.f.

(69) The instantaneous final local clearance deviation S.sub.f at a height Z is in this case is equal to the difference between the instantaneous final local stator flank deviation T.sub.fi and the instantaneous final local rotor flank deviation R.sub.fu at this height z.

(70) This already shows that the position of the rotor 6 in the stator 7 plays an important role in determining the instantaneous final local clearance deviation S.sub.f, because it is this position that determines which flanks 10 and 19 or 11 and 18 form the instantaneous final local clearance S.sub.f.

(71) Moreover, this position of the rotor 6 in the stator 7 determines which base edge 31 of a stator base 34, which in principle is immovable, is opposite a rotor tip 33, or which rotor base 35, which can also be considered as immovable, is opposite a stator tip 36.

(72) This is clarified on the basis of FIG. 15 for example, whereby the central axis BB of the rotor 6 is brought to a position that is diametrical with respect to its position shown in FIG. 13.

(73) In this position of the rotor 6 the instantaneous final local transverse internal clearance S.sub.f is formed by the distances concerned between the internal rotor flank 19 and the external stator flank 10.

(74) In this case of FIG. 15, the same deformation of the stator scroll 8 and the rotor scroll 16 as in the case of FIG. 13, more specifically a deformation whereby the rotor tips 33 and the stator tips 35 move towards the outside 25 of the scroll compressor 1, has the opposite effect on the instantaneous local transverse internal clearance S.sub.f.

(75) Indeed, in the instantaneous sealing plane MM concerned of FIG. 15, the rotor tips 33 bend away from the opposite stator bases 36, such that the local transverse internal clearance S.sub.f increases at a small height Z at the rotor tips 33 with respect to the basic clearance W, while the stator tips 34 bend towards the opposite rotor bases 35, such that the local internal clearance S.sub.f decreases at a large height Z at the stator tips 34 with respect to the basic clearance W, whereby the clearance S.sub.f thus increases from the rotor bases 35, while in FIG. 13 the clearance S decreased from the rotor bases 35.

(76) Hereby at each height Z the instantaneous local rotor flank deviation R.sub.fi concerned makes a contribution that increases the local transverse internal clearance S.sub.f, while the instantaneous local stator flank deviation T.sub.fu makes a contribution that decreases the local transverse internal clearance S.sub.f.

(77) In the situation of FIG. 15, the instantaneous local clearance deviation S.sub.f at a height Z is equal to the difference between the instantaneous local rotor flank deviation R.sub.fi concerned and the instantaneous local stator flank deviation T.sub.fu concerned, whereby the instantaneous local transverse clearance S.sub.f is always equal to the basic clearance W plus the instantaneous local clearance deviation S.sub.f.

(78) If the initial situation is now compared to the final situation, the following can be stated.

(79) When the known scroll compressor 1 is stationary, the form of the rotor flanks 18 and 19 and the stator flanks 10 and 11 initially do not present an initial local rotor flank deviation R.sub.0i or R.sub.0u and no initial local stator flank deviation T.sub.0i or T.sub.0u at any point.

(80) When the known scroll compressor 1 is operating in nominal service, the stator scroll 8 and the rotor scroll 16 are deformed into a form whereby there are instantaneous final local stator flank deviations T.sub.fi and T.sub.fu and instantaneous final local rotor flank deviations R.sub.fi and R.sub.fu that are different to zero.

(81) This means that over the entire surfaces of the spiral flanks 10, 11, 18 and 19, the stator flank deviations T.sub.fi and T.sub.fu and the rotor flank deviations R.sub.fi and R.sub.fu have increased after the scroll compressor 1 has been brought to nominal service compared to the form when stationary.

(82) In brief, during nominal operation of the known scroll compressors 1, the spiral flanks 10, 11, 18 and 19 deviate more from the ideal spiral flanks than when the known scroll compressors 1 are stationary, and this at each point of the flanks concerned.

(83) Moreover, as practically no deviation is possible at the stator bases 36 and the rotor bases 35, this yields a strong variation of the circulating clearance profile over the height Z, as demonstrated above.

(84) FIGS. 16 to 19 show, analogously to FIGS. 12 to 15 respectively, the corresponding situations in a scroll compressor 1 according to the invention.

(85) In the embodiment shown this scroll compressor 1 is provided with an adapted flank section 37, more specifically a section of the outward rotor flank 18 whose form is initially adapted at each point of the adapted flank section 37 concerned in an initial stationary state of the scroll compressor 1, shown in FIGS. 16 and 18 for diametrical positions of the rotor 6, by there being a local initial rotor flank deviation R.sub.0u that is different from zero, whereby in particular this R.sub.0u is less than zero.

(86) In other words it can be said that the adapted flank section 37 of the outward rotor flank 18 presents, as of a certain height Z, a certain setback F with respect to the ideal spiral flanks 23 in the direction of the central axis BB.

(87) The adapted flank section 37 concerned also has a discontinuous profile, whereby more specifically the thickness G of the rotor scroll 16 decreases stepwise in the direction from the rotor base 35 to the rotor tip 33, and in this case has one step change over the height Z.

(88) Moreover, the rotor scroll 16 is profiled such that the opposite flank section 38 of the inward flank 19 of the rotor scroll 16 is made flat when stationary and is in a perpendicular position on the rotor plate 21, so that the rotor scroll 16 has a thickness K that is greater at the stator base 35 than at the stator tip 33.

(89) In a completely similar way, in the embodiment shown the outward stator flank 10 is provided with an adapted flank section 39 whose form is initially adapted by there being, at each point of the adapted flank section 39 concerned in an initial stationary situation of the scroll compressor 1, a local initial stator flank deviation T.sub.0u that is different to zero, whereby in particular this T.sub.0u is less than zero.

(90) The adapted flank section 39 also has a discontinuous profile with the same setback F, whereby the thickness L of the stator scroll 8 over the height Z has one step change in the direction from the stator base 36 to the stator tip 34.

(91) At the other inward flank 11, the stator scroll 8 also has an opposite flank section 40, which is made flat when stationary and is in a perpendicular position on the stator plate 13, so that the stator scroll 8 has a thickness L that is greater at the stator base 36 than at the stator tip 34.

(92) In brief, with such a scroll compressor 1 according to the invention, at least certain flank sections 37 and 39 initially deviate from the ideal spiral flanks 32 when stationary.

(93) When the scroll compressor 1 according to the invention goes from the initial stationary state to a final state in nominal service, the stator scroll 8 and the rotor scroll 16 deform, as shown in more detail in FIGS. 17 and 19.

(94) According to the invention this deformation is such that during the movement of the rotor 6 in nominal service, at each point of an aforementioned adapted rotor flank section 37 and stator flank section 39, and in each position of the rotor 6, there is an instantaneous final local rotor flank deviation R.sub.fu and an instantaneous final local stator flank deviation T.sub.fu respectively, which in absolute value is less than the corresponding local initial rotor flank deviation R.sub.0u and the local initial stator flank deviation T.sub.0u respectively at the same point when the rotor 6 is stationary in the corresponding position.

(95) In brief, when operating the scroll compressor in nominal service, the adapted flank sections 37 and 39 concerned are deformed into a form that fits more closely to the ideal spiral flanks 32.

(96) It is felt intuitively here that such a deformation results in a less varying circulating clearance profile over the height Z in the scroll compressor 1.

(97) The adaptations of the aforementioned flank sections 37 and 39 and the local deformations following from this however are not so simply directly linked to their influence on the instantaneous final local internal clearances S.sub.f and accompanying instantaneous final clearance deviations S.sub.f.

(98) Indeed, when the rotor 6 for example is in a position corresponding to that shown in FIG. 17, the instantaneous final local internal clearance S.sub.f is determined by the radial distance S.sub.f between the outward rotor flank 18, that is provided with an adapted flank section 37 and the inward stator flank 11, which in this case is constructed like the known scroll compressors 1.

(99) Therefore, in the position of FIG. 17, between the rotor tip 33 and the opposite stator base 36 in every case there is an improvement of the instantaneous final local transverse clearance S.sub.f compared to the situation of FIG. 13 in the known scroll compressors 1, where no flank section has been initially adapted, as the opposite stator base 36 is barely deformed, while in this embodiment the rotor tip 33 is closer to the ideal spiral flanks 32 due to the deformation.

(100) Due to a good choice of the adaptations to the flank section 37 of the rotor scroll 16 it can be ensured that in the state concerned the instantaneous final local transverse clearance S.sub.f at the rotor tip 33 is equal to the basic clearance W and there is thus no local instantaneous final circulating clearance deviation S.sub.f.

(101) The instantaneous final local transverse clearance S.sub.f between the rotor base 35 and the opposite stator 34 in this position of the rotor 6 according to FIG. 17, is barely changed with respect to what was the case in the known scroll compressor 1 shown in FIG. 13, and the instantaneous final local transverse clearance S.sub.f at the height Z at the rotor base 35 is even possibly somewhat increased with respect to what was the case in the known scroll compressor 1 on account of the adaptations to the opposite stator scroll 6.

(102) Hereby an adapted flank section 39 is provided at the stator tip 34 where the thickness of the stator scroll 8 is reduced with respect to the thickness of the stator scroll 8 in a similar known scroll compressor 1, such that the stator tip 34 in the scroll compressor 1 according to the invention in the position of FIG. 17 possibly bends out even further to the outside 25 of the scroll compressor 1 than is the case with the known scroll compressor 1 shown in FIG. 13.

(103) In the other position of the rotor shown in FIG. 19, diametrically opposite the position of FIG. 17, a similar phenomenon occurs.

(104) More specifically, the instantaneous final local transverse clearance S.sub.f in this position of FIG. 19 is the difference in the radial distance S.sub.f at a certain height Z between the external stator flank 11 and the internal rotor flank 19.

(105) The adapted flank section 39 according to the invention of the stator flank 8 hereby takes on a form, in nominal service, at the stator tip 34 that is closer to an ideal flank section 32 compared to its initial form, whereby the opposite rotor base 35 is practically not deformed, so that the instantaneous final local transverse clearance S.sub.f at the stator tip 34 at a height Z is closer to the basic clearance W and there is a local circulating clearance deviation S.sub.f at this height Z that is practically zero.

(106) The stator base 36 practically does not deform during a transition from the stationary state to nominal service of the scroll compressor 1, while the opposite rotor tip 33 undergoes a deformation that is at least as large as in the known scroll compressors 1, as the internal rotor flank 19 is not provided with an adapted flank section while the rotor tip 33 is made narrower, such that the instantaneous final local transverse clearance S.sub.f in the case of FIG. 19 at the stator base 36 is at least as large locally as in the known scroll compressors, also with a relatively large clearance deviation S.sub.f at this height Z.

(107) In brief, in the one position of the rotor 6 according to FIGS. 16 and 17 the adapted flank section 37 of the outward rotor flank 18 makes a smaller contribution to the instantaneous final clearance deviation S.sub.f, while the other adapted flank section 39 of the inward stator flank 11 makes the same or a somewhat larger contribution to the instantaneous final clearance deviation S.sub.f in this position, compared to what happens in the known scroll compressors 1.

(108) In another position of the rotor 6, shown in FIGS. 18 and 19, it is precisely the reverse.

(109) Nevertheless, it turns out to be possible according to the invention, using computer calculations with finite element methods, to design adapted flank sections 37 or 39 with an additional deviant form and to make a prediction of the circulating clearance profile in an instantaneous sealing plane MM during nominal operation, whereby a generally better instantaneous final circulating clearance profile is obtained, whereby the instantaneous final local transverse clearance S.sub.f varies less over the height Z in an instantaneous sealing plane MM and in general approximates the basic clearance W more closely than is the case with the known scroll compressors 1.

(110) The positive effect of the adaptation of one or more flank sections of the rotor scroll 16 or the stator scroll 8 on the instantaneous final circulating clearance deviation S.sub.f is embodied in the contribution that the deformation of the flank section concerned makes to the total clearance deviation S.sub.f.

(111) In the case of FIG. 16 for example, the initial rotor flank deviation R.sub.0u in the flank section 37 at specific heights Z is less than zero, whereby the absolute value of this rotor flank deviation R.sub.0u makes a certain initial local contribution R.sub.0u to an instantaneous initial local clearance deviation S.sub.0 at the height Z concerned in the instantaneous sealing plane MM concerned.

(112) During the operation of the scroll compressor 1 in nominal service, the outward rotor flank 18 concerned is deformed, which results in a final local rotor flank deviation R.sub.fu in the flank section 37 at the different heights Z concerned that is always less than zero, but the absolute value of which makes a certain final local contribution R.sub.fu to an instantaneous final local clearance deviation S.sub.f at the height Z concerned in the instantaneous sealing plane MM concerned, which is less than the absolute value of the aforementioned initial local contribution R.sub.0u.

(113) This positive effect as a result of the adapted flank section 37 on the instantaneous final local internal clearance S is only present in certain positions of the rotor 6 in the stator 7, as shown in FIG. 19 for example, in which position of the rotor according to FIG. 19 the adapted flank section 39 yields a positive effect, as set out above.

(114) In the known scroll compressors 1, however, in no flank section of the rotor scroll 16 or the stator scroll 8 and in no position of the rotor 6 in the stator 8 is there such a positive effect on the final circulating clearance deviation S.sub.f, as the two flanks 10 and 19 or 11 and 18, which define a minimum opening 29 and between which there is an instantaneous final local transverse clearance S.sub.f, in all circumstances deviate more from the ideal spiral flanks 32 than in the initial state, whereby this initial state rather corresponds to the ideal.

(115) The embodiment of a scroll compressor 1 according to the invention discussed so far is of course only a simple example, whereby in adapted flank sections 37 and 39, the thickness K of the rotor scroll 16 concerned or the thickness L of the stator scroll 8 respectively has been initially reduced locally with a discontinuous step change F.

(116) According to the invention it is not excluded to adapt the flank sections of the rotor scroll 16 and the stator scroll in a different way, and preferably more sophisticated way, in order to give an adapted initial form.

(117) In general it is not excluded according to the invention that at least one of the stator flanks 10 and 11 or the rotor flanks 18 or in its entirety forms an aforementioned flank section 37 or 39 respectively, or that more than one of the stator flanks 10 and 11 or rotor flanks 18 and 19 in their entirety form an aforementioned adapted flank section 37 of 39.

(118) Preferably according to the invention, the initial form of the scroll compressor is designed such that for at least some of the positions, and ideally for all positions adopted by the rotor 6 during its movement, the local transverse internal clearances S over the height Z of the stator flank 10 or 11 and rotor flank 19 or 18 are constant in nominal service, so that these local transverse internal clearances S over the height Z present a final instantaneous profile without variation, or in other words with a variation equal to zero in the positions concerned.

(119) A few simple lines of thought are illustrated in the remaining FIGS. 20 to 35.

(120) In the example of FIGS. 20 to 23 the outward rotor flank 18 is provided with an adapted flank section 37 that also has a discontinuous profile, such as in the foregoing embodiment, but whereby the thickness K of the rotor scroll 16 at the flank section 37 has a number of step changes over the height Z, more specifically two in this case.

(121) Such step changes are preferably of the order of magnitude of 10 m and 300 m.

(122) In this way a more accurate fit can be obtained of the flank section 37 concerned of the rotor scroll 16 in the final situation during nominal operation of the scroll compressor, with a less varying instantaneous final local internal clearance S.sub.f and instantaneous final clearance deviation S.sub.f of the scroll compressor 1 at the location of the flank section 37, at least for certain positions of the rotor 6 in the stator 7.

(123) Analogously the outward stator flank 10 is also provided with an adapted flank section 39 that also has a discontinuous profile whereby the thickness L of the stator scroll 8 in the flank section 39 has two step changes over its height Z, with similar aforementioned effects on the instantaneous final clearance S.sub.f and instantaneous final clearance deviation S.sub.f.

(124) Of course by providing the adapted flank sections, whereby more and more discontinuous step changes are provided, the expected deformation is adapted in an increasingly detailed way.

(125) In extremis this leads to designs whereby an adapted flank section of a stator flank 10 or 11 or a rotor flank 18 has a continuous profile, as is the case for example in FIGS. 28 to 35, whereby in the case of these FIGS. 28 to 35 the outward rotor flank 18 and the outward stator flank 11 initially present a certain inclination, while the inward rotor flank 19 and the inward stator flank 10 are initially perpendicular with respect to the rotor plate 21 and stator plate 13 respectively.

(126) In the example of FIGS. 24 to 27 and of FIGS. 32 to 35, the stator scroll 8 is constructed with stator flanks 10 and 11 that are both perpendicular to the stator plate 13 when the scroll compressor 1 is stationary, while the rotor scroll 18 is constructed with rotor flanks 18 and 19 that both present a certain setback when the scroll compressor 1 is stationary in the case of FIGS. 24 to 27, more specifically they present a setback in a number of steps, or an inclination in the case of FIG. 32 or 35 with respect to the rotor plate 21, whereby the flanks 18 concerned and in their entirety form adapted flank sections 37 and 38.

(127) As is shown by the drawings, similar effects can thus be obtained as in the previous embodiments with regard to making the profile of the instantaneous final local clearance S in certain instantaneous minimum openings 29 more even, and to reducing the instantaneous final clearance deviations S.sub.f at certain heights Z with respect to the stator plate 13 and in certain positions of the rotor 6 in the stator 7, whereby this time an adapted section of a rotor flank 18 or 19 always ensures the intended effect.

(128) Preferably the adapted flank sections 37 and 38 in these embodiments which, when stationary, present a certain setback or inclination, will be perpendicular to the rotor plate 21 in nominal service.

(129) It is not excluded in an analogous way to construct the rotor flanks 18 and 19 so that they are initially perpendicular to the rotor plate 21, while both stator flanks 10 and 11 of adapted flank sections 39 and 40 are designed to influence the instantaneous final clearance S.sub.f and instantaneous final clearance deviation S.sub.f.

(130) Other embodiments, whereby adapted flank sections of the scroll compressor 1 have a profile that is a combination of discontinuous and continuous sections with more or less curved forms or otherwise, are not excluded according to the invention.

(131) The present invention is by no means limited to the embodiment of a scroll compressor 1 according to the invention, described as an example and illustrated in the drawings, but a scroll compressor 1 according to the invention can be realised in all kinds of forms and dimensions, without departing from the scope of the invention.