Compressor for r718 with adjustment of an internal volume ratio

Abstract

The invention relates to the compression of steam in the form of R718 with or without the addition of additives in the form of an aqueous solution in rotational displacement machines, in particular for refrigeration, air-conditioning, and heat pump technology. The aim of the invention is to prevent overcompression or undercompression, which impairs efficiency, as much as possible during operation by adapting the effective internal volume ratio, the so-called iV value, in the displacement machine as simply as possible. According to the invention, this is achieved in that for a rotor profile length LR, the compressor housing (1) has planar, i.e. flat, iV discs (3j) over a length LiV starting from the outlet side (1.2), having the index j for 1 ≤ j ≤ n, where n is the number of said iV discs (3j), wherein n ≥ 1, with a width bj for each iV disc (3j) and comprising planar surfaces PF preferably perpendicular to the neutral axis AN, each said iV disc (3j) being moved in a controlled manner by a respective distance si, where 0 < si ≤ sj, individually via respective movement controllers (5j) for each iV disc (3j) for the respective operating condition.

Description

State of the art

[0001] A screw compressor with variable volume and adjustable compression is known from US Pat. No. 3,151,806 A. The screw compressor comprises screws, volume control valves, and compression control valves that can be moved perpendicular to the rotational axes of the screws.

[0002] WO 2011 / 149444 A1 discloses an internal combustion engine coupled to a supercharger operable to supply varying amounts of air to the engine. The supercharger includes a pair of screw rotors driven by the engine to supply air to the engine, and a control device for varying the mass and pressure of the air supplied to the engine.

[0003] EP 0 775 826 A1 discloses a screw compressor for gas circuits comprising a compressor housing with an inlet and an outlet for the medium to be compressed, and with two screw bodies arranged in a screw chamber of the compressor housing and extending between the inlet and the outlet, which screw bodies engage with each other to form closed compression spaces located between the inlet and the outlet.In a wall region of the screw chamber which delimits compression chambers closed at maximum power, a plurality of power control openings are provided, each arranged at locations in this wall region corresponding to different compression ratios, each of which can be closed with one of a plurality of separately actuated control bodies either by the control body essentially filling the power control opening, or by being connectable to a return flow channel connected to the inlet by the control body being at a distance from the power control opening.

[0004] DE 195 19 262 A1 describes a screw compressor with an adjustable displacement, comprising at least one main rotor and at least one secondary rotor, which are arranged in a common housing, mesh with each other, and convey a medium to be compressed from an inlet channel to an outlet channel. The inlet channel is delimited by at least one housing segment slidably arranged in the housing, which, on its sealing side facing the rotors, follows the course of the rotor envelope. The at least one housing segment is guided slidably in a shaft transverse to the rotor axes.

[0005] From WO 2019 / 002363 A1, a displacement system for the refrigerant R718 with a compressor machine, an evaporator and a condenser is known, wherein the open compressor machine is designed as a spindle compressor in the form of a 2-shaft rotary displacement machine for conveying and compressing gaseous conveying media.

[0006] The refrigeration market is currently undergoing a transformation, and the so-called "F-Gas Regulation" pursuant to Regulation (EC) No. 842 / 2006 and No. 517 / 2014 on fluorinated greenhouse gases is being discussed as a challenge to phase out the prevalent fluorinated refrigerants (HFCs, HFOs) due to their harmful effects on the climate and the environment. Therefore, there is a strong desire in refrigeration technology for natural refrigerants, with water in particular being attractive due to its good thermodynamic properties.

[0007] However, the widespread implementation of water as a refrigerant R718 has so far stalled due to the fact that, for example, it requires a flow rate approximately 300 times greater than that of ammonia for the same function, while maintaining the same performance. At the same time, the pressure ratio is quite high, ideally above a factor of 10, which increases the demands on a compressor enormously. The compressor must also be oil-free and operate as efficiently as possible at negative pressures, namely between 6 mbar and 200 mbar, and possibly even higher.

[0008] The disruptive nature of water as a refrigerant R718 is undisputed and will abruptly end the intense global discussions on the known environmental and climate problems associated with today's refrigerants.

[0009] To date, attempts have been made to address this challenge using turbo compressors. Despite their two-stage design with intercooling, these machines only achieve lower pressure ratios of approximately 6, resulting in the insufficient heat transfer to the condenser (condenser) in the refrigeration circuit. Added to this is the serious disadvantage of turbomachines regarding their soft operating characteristics (i.e., pressure values ​​versus volume flow), which are essential for ensuring stable operating points for different operating points.

[0010] A positive displacement compressor for steam vapor compression is undoubtedly the better solution for overcoming these challenges in R718 refrigeration cycles. However, for this R718 application, some weaknesses of current positive displacement compressors must be addressed and the compressor's efficiency improved. Since these compressors are preferably twin-shaft rotary positive displacement compressors, for example, as described in DE 10 2018 001 519 A1, a key feature of these compressors is their so-called "internal volume ratio," hereinafter referred to as "iV." This iV value is the ratio between the working chamber volume on the inlet side and the working chamber volume on the outlet side, a dimensionless number, and is determined for the spindle rotor pair primarily by the intersection angle, diameter, and pitch.This iV value is essentially a fixed, unchangeable value for a manufactured spindle rotor pair, which for the R718 task is usually in the range between 3 and 20 in order to be able to fulfill a wide operating range. However, there are different and variable operating conditions in the application, for example, between hot and cold ambient temperatures, which fluctuate frequently. Therefore, it would be advantageous if the iV value of the R718 compressor could be adjusted in order to best avoid the efficiency-damaging over- or under-compression and to be able to set the optimal effective iV value at each operating point. Previous approaches, for example using control balls, are relatively unfavorable because both the required flow cross-sections and the pressure differences are quite small, so that the effective iV value can only inadequately prevent the harmful over- or under-compression.Accordingly, compared to the prior art, the object of the present invention can be described as follows. Notes

[0011] a) When reference is made here to the R718* compressor, this also includes the addition of, for example, ethanol, if the compressor is operated below 0°C and ice formation must be avoided. To include this admixture, the term R718* compressor will be used from now on in this text, with the asterisk * indicating the addition, preferably with an alcohol (such as ethanol) as an aqueous solution. b) When reference is made to "multi-stage" for the spindle rotor pair (2), this means that there are several enclosed spindle rotor pair working chambers between the inlet (1.1) and the outlet (1.2), in which the known profile wrap angle extends significantly beyond 360°. This multi-stage nature of the spindle rotor pair (2) can be a basic prerequisite for the implementation of this invention for preferred embodiments. Description of the invention: Task, solution Advantages:

[0012] Compared to the state of the art, an R718* positive displacement compressor must be designed in such a way that the effective iV value can be reliably adapted to different operating conditions as simply, safely and cost-effectively as possible over a wide operating range, as efficiently and quickly as possible, in order to avoid over- or under-compression, which is detrimental to efficiency, as far as possible during operation.

[0013] According to the invention, this object for iV adjustment in an R718* positive displacement compressor is achieved by a compressor according to claim 1.

[0014] The compressor comprises a pair of spindle rotors (2) in a compressor housing. The rotational axes AR of the spindle rotors of the spindle rotor pair (2) are aligned at an angle y > 0 to each other, with a neutral axis AN representing an angle bisector of the rotational axes AR. The compressor housing (1) has, starting from an outlet side (1.2), with a rotor profile length LR over a length L.iVj, flat (i.e. level) iV-disks (3.j) with index j for 1 ≤ j ≤ n with n as the number of these iV-disks (3.j) with n > 1 with a width bj per iV-disk (3.j) with flat surfaces PF perpendicular to the neutral axis AN, wherein over the length L.iV an inner contour of the compressor housing (1) is provided by the iV-disks (3.j), wherein the iV-disks (3.j) are individually moved by a distance si with 0 < si ≤ s for the respective operating conditions via movement control devices (5).j are specifically shifted parallel to the neutral axis AN and thus gas outlets G o1 between the iV discs (3.j), G o2 via spindle rotor heads and G oS via a gas conveying thread of the spindle rotor pair into a condensation chamber (1.2) are enabled in such a way that over- or under-compression is avoided as far as possible.

[0015] The number n and the widths bj per iV disc (3.j) depend on the pitch profile and the desired application range of the R718* positive displacement compressor and are therefore designed for each application. The travel distances s can be designed differently for each iV disc (3.j) and are then referred to as sj. It is particularly useful and advantageous that practically any intermediate position si with 0 < si ≤ sj on the travel length s can be set via the movement control devices (5), so that the gas outlet G o1 and G o2 can be specifically adjusted for the current operating conditions, while gas outlet as G oS continues to occur via the gas delivery thread of the spindle rotor pair (2).

[0016] Preferably, the precise positioning of each iV disc (3.j) is carried out via positioning pins (4) to the compressor housing (1) and to each other, so that in the closed state, as for example in Fig. 1shown when all iV discs lie on one another, preferably clearly defined by the positioning pins (4), the play values ​​between the spindle rotor pair (2) and the compressor housing (1) are always maintained, and preferably any contact between the spindle rotor pair (2) and the compressor housing (1) is reliably avoided, wherein more preferably in this state of the completely adjacent iV discs the manufacturing machining of the inner contour of the compressor housing (1) also takes place.

[0017] With the rotor profile length LR, the length L.iV can now be selected such that at least the first working chamber on the inlet side is closed. In the so-called "closed" state, i.e., when all iV discs are fully engaged, the maximum iV value is achieved.

[0018] When manufacturing the inner contour surrounding the spindle rotor pair (2) in the compressor housing (1), preferably all iV discs (3) can be pressed flat and firmly onto one another in accordance with the closed state and clearly fixed via the positioning pins (4), so that the entire inner contour for the compressor housing (1) and at the same time for all iV discs (3) can be manufactured simultaneously, so that the desired clearance values ​​for the spindle rotor pair (2) can be achieved consistently over the entire length LR.

[0019] Further preferably, guide support surfaces (FF) can be designed in such a way that when the respective iV discs (3.j) are displaced with appropriately suitable force exerted via the movement control devices (5.j) for displacing the respective iV discs (3.j), the circumferentially uniform movement of the respective iV discs (3.j) is ensured over corresponding guide lengths and guide accuracies and tilting of the iV discs (3.j) is avoided.

[0020] Even more preferably, the guide support surfaces (FF) can be related to the central guide diameter ØDF as well as the uniform application of force via the movement control devices (5.j) per iV disc (3.j).

[0021] To reliably prevent the respective iV discs from tilting when these iV discs move, guide support surfaces FF can be provided and the force for moving the iV discs via the movement control devices (5) is preferably applied uniformly over the entire circumference by reference to the support ØDF central to the neutral axis AN to prevent tilting or jamming of the iV disc movement.

[0022] The motion control devices (5) for each iV disc are preferably operated by R718* water hydraulics.

[0023] Furthermore, it can be provided that for each operating point any intermediate position si with 0 < si ≤ sj with sj as the maximum displacement path per iV disc (3.j) is made possible.

[0024] Just like the gas outlet G oS and G o2, the gas outlet G o1 also preferably occurs directly into the condensation chamber (1.2).

[0025] It is preferably provided that the flat surfaces (PF) of each iV disc (3.j) are designed with correspondingly smooth, bright and preferably ground surfaces for easy sealing to one another and to the compressor housing (1).

[0026] The sealing between adjacent iV discs is therefore preferably achieved via the flat plane surfaces PF with correspondingly bright or smooth contact / touch surfaces (preferably ground flat) and can, if necessary, be improved, for example, by means of inserted O-rings in corresponding grooves with a holding function.

[0027] Depending on the specific application, the operating conditions, and the selected pitch of the spindle rotor pair (2), the number n of iV discs (3.j) and their width bj can be determined in such a way that efficiency-damaging over- or under-compression is best avoided for each specific application. More precise instructions are not possible, as each compressor manufacturer implements this individually for its customer requirements.

[0028] Furthermore, it can be provided that the iV discs (3.j) are positioned for the respective working / operating point via the movement control devices (5.j) for each iV disc (3.j) in such a way that the R718* compressor is operated with the lowest energy consumption.

[0029] It is preferably provided that, with a rotor profile length LR, the length L.iV of the iV discs (3.j) is designed such that at least the first working chambers on the compressor inlet side (1.1) always remain closed.

[0030] In addition, it can be provided that the positioning pins (4) take over both the exact positioning of each iV disc (3.j) and the guidance and driving of the iV discs when they are moved via the movement control devices (5.j).

[0031] The greatest challenge in the most energy-efficient iV value adjustment is that sufficient flow cross-sections must be created for different operating points without significant pressure losses, because the absolute pressure differences are very small, for example, if the widest working range (for which the compressor iV value is preferably designed) of 10 mbar, corresponds to an evaporation temperature of about 7°C at 200 mbar for pure R718, corresponds to a condensation temperature of about 60°C for pure R718 is to be compressed (also referred to as temperature lift), but at the same time under different operating conditions with the same machine it must also be compressed from 25 mbar to 90 mbar, for example. In this case the outlet at the compressor must be much earlier (i.e. at a lower iV value). In order for the pumped medium R718* to then escape earlier, the pressure differences as flow resistances must not be so great at the available cross-sections so that the pumped medium can flow out earlier with the lowest possible resistance. In concrete terms, these must only be pressure differences of a few mbar, i.e. well below 10 mbar, whereby the simple statement applies: the lower the pressure losses at the earlier outlet for lower temperature lifts, the more efficient the iV adjustment is.

[0032] It is precisely in this requirement that the present invention is particularly advantageous, because the inventive displacement of the flat iV discs creates extremely large cross sections with minimal pressure losses through individual positioning at 3-fold conveying medium outlet flows, namely: 1) G o1 = Outlet between the iV discs 2) G o2 = Outlet via the spindle rotor heads 3) G oS = Outlet via the gas feed thread of the spindle rotor pair

[0033] Another particularly advantageous feature is the simple manufacture combined with the best possible fit accuracy, as the manufacturing of the inner contour of the working chamber surrounding the spindle rotor pair (2) on the compressor housing (1) can be carried out with the iV discs (3) fully in place, with the iV discs (3) being positioned precisely and reproducibly via positioning pins (4).

[0034] In addition, the actual effective iV value can be flexibly adjusted to any intermediate position by targeted positioning si with 0 ≤ si ≤ sj in order to achieve the most efficient actual effective iV value for the respective operating point. Fig. 3 to 6 the respective path length sj is simplified only as s, a differentiation per iV-disk (3.j) is of course feasible and depends on the respective requirements.

[0035] Advantageously, when each iV disc is closed, the exact situation as when the inner contour was manufactured is achieved again, and when removed, i.e. when the iV discs (3.j) are opened, the play values ​​are always uncritical due to the increase in the play values ​​between the iV discs (3.j) and the spindle rotor heads. Short description of the characters

[0036] The invention is explained in more detail below with reference to the accompanying figures. They show: Fig. 1 is a sectional view of an R718* compressor with all iV discs in place, Fig. 2 is a sectional view of an R718* compressor perpendicular to a neutral axis, Fig. 3 is a detailed enlargement of an R718* compressor, Fig. 4 is a sectional view of an R718* compressor with a first shifted iV disc, Fig. 5 is a sectional view of an R718* compressor with several shifted iV discs, and Fig. 6 is a sectional view of an R718* compressor with all iV discs shifted. Detailed description of the characters

[0037] The gas feed external thread of each spindle rotor (2) is shown as hatching under the designation "ANGLE" according to the drawing software AutoCAD (i.e. 2 lines at 45° each, perpendicular to each other, always aligned).

[0038] Fig. 1shows an example of a sectional view through the R718* compressor when all iV disks (3.j) for 1 ≤ j ≤ n with n as the number of these iV disks (3.j) with a width bj per iV disk (3.j) are fully applied, so that the maximum iV value for the respective compressor design is effective. As gas fluid flow (G) there is therefore only the outlet G oS via the gas delivery thread of the spindle rotor pair (2). The number n of iV disks (3.j) depends on the respective requirement profile when using the R718* compressor, whereby the following applies: the more iV disks (3.j) are implemented, the more finely the actually effective iV value can be graduated, whereby the width bj of the respective iV disks must be taken into account.

[0039] In addition, exemplary flat surfaces PF are shown as dashed lines, preferably perpendicular to the neutral axis AN. To prevent tilting as reliably as possible during movement of the iV pulleys (3), exemplary guide support surfaces FFz are also shown centrically to the neutral axis AN relative to ØDF.

[0040] Fig. 2 shows an example of a cross-hatched sectional view perpendicular to the neutral axis AN for a flat surface PF. Also shown are the preferably centric guide support surfaces FF for each iV disc with the ØDF specified, as well as the positioning pins (4) in pairs for each iV disc for the precise positioning of each iV disc relative to the spindle rotor pair (2).

[0041] Different positions of the iV discs (3.j) for the simple realization of different iV values ​​according to the invention are shown in the following illustrations of Fig. 3 to Fig. 6shown, whereby for better clarity only one side is shown, preferably mirrored to the neutral axis AN.

[0042] The exemplary sectional view of the Fig. 3 as a detailed enlargement to Fig. 1 The diagram titled "iV.m" shows the so-called "closed" position, when all iV discs (3) are fully engaged, with the motion control devices (5) set to B.Sg, thus allowing the maximum iV value to be applied. Thus, only the gas flow G oS leaves the R718* compressor via the gas delivery thread. The pressure ratio is then p 2.H at the compressor outlet (1.2) divided by p 1 * at the inlet (1.1).

[0043] The exemplary sectional view of the Fig. 4 as a continuation of Fig. 3under the title "iV.n1" shows a position when moving the first iV disc (3.1), in which the motion control B.Si on the control device (5) for this iV disc (3.1) specifically sets the displacement path si with 0 < si < s for a desired intermediate position of this iV disc and thus for the first time the maximum iV value from the Fig. 3 is exceeded, i.e., when the first iV disc (3.1) leaves the "closed" position. The first iV disc (3.1) is counted from the compressor outlet (1.2). In this position, the gas flows G o1 and G o2 as well as G oS leave the R718* compressor. Unlike in Fig. 3 the pressure ratio is then p 2.N1 at the compressor outlet (1.2) divided by p 1 *° at the inlet (1.1) at the corresponding evaporator or condenser temperatures.

[0044] The exemplary sectional view of the Fig. 5 as a continuation of Fig. 3 and 4under the title "iV.nj" shows any position when moving several iV discs (3.j*) with 1 ≤ j* ≤ n for n as the number of iV discs, in that the motion control B.Si on the control devices (5) for these iV discs (3.j) specifically sets the displacement path si with 0 < si < s for a desired intermediate position of these iV discs (the plural is important) and thus each application-specific desired intermediate value for the effectively effective iV value is achieved.

[0045] In this position, the gas flows G o1 and G o2 as well as G oS leave the R718* compressor. Unlike in Fig. 3 and Fig. 4 the pressure ratio is then p 2.NN at the compressor outlet (1.2) divided by p 1 ** at the inlet (1.1) at the corresponding evaporator or condenser temperatures.

[0046] The exemplary sectional view of the Fig. 6 as a continuation of Fig. 3 and 4 and 5under the title "iV.L" shows the position of the minimum effective iV value, in which all iV discs are moved by their full displacement path via motion control B.So for the open position.

[0047] In this position, the gas flows Go1 and Go2, as well as GoS, leave the R718* compressor. Unlike before, the pressure ratio is then p 2.L at the compressor outlet (1.2) divided by p 1 *'* at the inlet (1.1) at the corresponding evaporator and condenser temperatures. List of reference symbols

[0048] 1. Compressor housing with an inlet side (1.1) with pressure p 1 and an outlet side (1.2) with p 2 with a neutral axis AN as bisector to the axis AR as rotation axis 1.1 Compressor inlet side in operation with the pressure p 1 at an evaporation temperature t 0 and at the same time forming the evaporator chamber 1.2Compressor outlet side in operation with the pressure p 2 at a condensation temperature tc and at the same time forming the condensation space 2. Spindle rotor pair, preferably with 2-tooth mirror-image identical and multi-stage gas conveying external thread and each spindle rotor with a rotation axis AR , at the angle γ to each other and the neutral axis 3. iV-disks for a desired application area with the width bj per iV-disk (3.j) with index j at 1 ≤ j ≤ n and n as the number of iV-disks with n > 1 4. Position pins, preferably with guide length and driving function 5. Movement control devices per iV disc (3.j), preferably operated by water hydraulics List of markings

[0049] ØDF to the neutral axis AN central guide diameter for the iV discs (3) TOneutral axis as bisector of both rotor axes AR with the angle γ to each other for mirror-image identical spindle rotors AR Rotation axis per spindle rotor, or so-called center line FF Guide support surfaces to prevent tilting of the iV discs (3.j), preferably designed as circular segments (to save material) with FFz Guide support surfaces centric to the neutral axis AN with the ØDF PF Flat surfaces between the iV-disks, in case of flat installation thanks to a smooth contact surface (preferably ground) sealing to the adjacent iV-disk, in Fig. 1 shown as a dashed line G Gas fluid flow G in with index "in" at the inlet of the compressor G o with index "o" at the compressor outlet, divided by shifted iV discs into G o1 Leakage between the IV discs Go2 Exit via the spindle rotor heads G oS Exit via the gas delivery thread of the spindle rotor pair BS Movement representation as positioning arrows for the respective iV disc (3.j) on the respective movement control devices (5) shown as: B.Sg Motion control for the closed position of the respective iV disc B.Si Motion control for any intermediate position of the respective iV disc B.So Motion control for open position of the respective iV disc bj Width of the respective iV disc (3.j) si Displacement path length for the respective iV disc with 0 < si ≤ s LR Spindle rotor profile length L.i.V Length of all IV discs

Claims

1. Compressor as a 2-shaft rotary positive displacement machine for conveying and compressing water vapor as refrigerant R718 , also with the addition of an alcohol as an aqueous solution, with a pair of spindle rotors (2) in a compressor housing (1) at a pressure p1 at the compressor inlet (1.1) and in operation with a higher pressure p2 at the compressor outlet (1.2), wherein rotation axes AR of spindle rotors of the spindle rotor pair (2) are aligned at an angle γ > 0 to one another, wherein a neutral axis AN represents an angle bisector of the rotation axes AR, characterized in that for the respective adaptation of an internal volume ratio (as "iV value") of the compressor, the compressor housing (1) of which, starting from an outlet side (1.2) with a rotor profile length L.R over a length L.iV j, has plane iV disks (3.j) with index j for 1≤ j≤ n with n as the number of these iV disks (3.j) with n> 1 at a width b.j per iV disk (3.j) with end faces P.F perpendicular to the neutral axis AN, wherein an inner contour of the compressor housing (1) is provided by the iV disks (3.j) over the length L.iV, wherein the iV disks (3.j) can be individually displaced for respective operating conditions via movement control devices (5.j) per iV disk (3.j) by a distance s.i each with 0< s.i≤ s.j with s.j as maximum displacement path per iV disk (3.j) parallel to the neutral axis AN and thus gas outlets Go1 between the iV disks (3.j), Go2 via spindle rotor heads as well as GoS via a gas feed thread of the spindle rotor pair (2) into a condensation chamber (1.2) in such a way that over- or under-compression in the compressor that is detrimental to efficiency can be avoided as far as possible.

2. Compressor according to claim 1, characterized in that the precise positioning of each iV disk (3.j) to the compressor housing (1) and to one another takes place via positioning pins (4), so that in the closed state, when all iV disks (3.j) are in clearly defined contact with one another via the positioning pins (4), the clearance values between the spindle rotor pair (2) and the compressor housing (1) are always maintained, wherein the production machining of the inner contour of the compressor housing (1) also takes place in this state of the fully contacting iV disks.

3. Compressor according to claim 1 or 2, characterized in that movement control devices (5.j) for each iV disk (3.j) are operated with water hydraulics and any intermediate position s.i with 0< s.i≤ s.j with s.j as the maximum displacement path for each iV disk (3.j) is specifically enabled for each operating point.

4. Compressor according to one of the preceding claims, characterized in that the flat surfaces (P.F) of each iV disk (3.j) are designed with correspondingly smooth, bright and preferably ground surfaces for easy sealing to one another and to the compressor housing (1).

5. Compressor according to one of the preceding claims, characterized in that guide support surfaces (F.F) are configured in such a way that, when the respective iV-discs (3.j) are displaced, the circumferentially uniform movement of the respective iV-discs (3.j) over corresponding guide lengths and guide accuracies is ensured with correspondingly suitable exertion of force via the movement control devices (5.j) for displacing the respective iV-discs (3.j), and tilting of the iV-discs (3.j) is avoided.

6. Compressor according to claim 5, characterized in that the guide support surfaces (F.F) are related to the central guide diameter ØDF as well as the uniform exertion of force via the movement control devices (5.j) for each iV disk (3.j).

7. Compressor according to one of the preceding claims, characterized in that the iV-discs (3.j) are positioned for the respective working / operating point via the movement control devices (5.j) for each iV-disc (3.j) in such a way that the compressor is operated with the lowest energy input.

8. Compressor according to one of the preceding claims, characterized in that with a rotor profile length L.R, the length L.iV of the iV disks (3.j) is configured in such a way that at least first working chambers on the compressor inlet side (1.1) always remain closed.

9. Compressor according to one of claims 2 to 8, characterized in that the positioning pins (4) take over both the exact positioning of each iV disk (3.j) and, when the iV disks are displaced via the movement control devices (5.j), their guidance and their entrainment.

10. Compressor according to one of the preceding claims, characterized in that the iV disks (3.j) can be selectively displaced parallel to the neutral axis AN, while forming a gap between the iV disks (3.j) and a gap between the inner contour and the gas feed thread of the spindle rotor pair (2), and in that the gas outlet Go1between the iV disks (3.j) is a gas outlet through the gap between the iV disks (3.j), and in that the gas outlet Go2 via the spindle rotor heads is a gas outlet through the gap between the inner contour and the gas feed thread.

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