EP1396640A2 - Screw compressor - Google Patents

Abstract

The compressor has two screw rotors arranged in rotor bores in a compressor casing (10), where the rotors compress a refrigerant. A refrigerant inlet in the casing receives the refrigerant from a supercooling circuit (30) and passes it to an inlet in a system of lines. The inlet opens out into compression spaces enclosed by the rotors and the bores. A damper channel precedes the inlet and associated with the system of lines.

Description

The invention relates to a screw compressor comprising two in one Compressor housing arranged in screw rotor bores screw rotor, which compress a refrigerant entering at a refrigerant inlet and leak at a refrigerant outlet, and one in the Compressor housing arranged inlet from a subcooling circuit coming, led via a line system to the inlet refrigerant, wherein the inlet is arranged such that it in from the screw rotors and Enclosed screw holes enclosed compression spaces opens.

In such screw compressors, the problem is that thereby, that which are enclosed by the screw and screw rotor bores Compaction spaces move past the inlet, pressure oscillations or pulsations occur in the piping system of the supercooling circuit and cause noise and, where appropriate, also lead to stability and leakage problems.

The invention is therefore based on the object to a screw compressor create, in which the pressure fluctuations occurring at the inlet or Pulsations in the least possible extent on the piping system of Propagate the subcooling circuit outside the compressor housing.

This object is achieved in a screw compressor of the beginning described type inventively achieved in that the inlet a the Line system associated damper channel upstream, in which There is refrigerant from the subcooling circuit.

By providing such a damper channel, it is possible to the occurring at the inlet pressure oscillations or pulsations to reduce.

In principle, it would be conceivable to use the damper channel in the piping system of the Provide subcooling.

However, to prevent from the outset that the pressure oscillations or pulsations of appreciable intensity into the piping system spreading and vibrating in this is preferable provided that the damper channel in the compressor housing is arranged.

With regard to the arrangement of the damper channel in the compressor housing are the most diverse possibilities conceivable.

So it would be conceivable, for example, the compressor housing of several Make housing sections and the damper channel in a housing section provided while the Schraubenläuferbohrungen in a other housing section are arranged.

It is particularly favorable, however, if the damper channel in a the Screw rotor bores receiving housing portion is formed, thus forms an integral unit, the forwarding of the pressure oscillations additionally reduced.

In principle, the damper channel can be used as a side arm of the pipe system trained and therefore not constantly flowed through.

In order to obtain a compact design arrangement of the damper channel is at an advantageous embodiment, a running through the compressor housing Intake passage provided as part of the conduit system, which of an outer, connected to the piping system of the subcooling circuit Connection to the compressor housing leads to the inlet, wherein the Damper channel is arranged in the inlet channel.

The realization of the damper channel in the compressor housing can also in done in a variety of ways.

For example, it would be conceivable, the damper channel in one piece in this mold in receiving compressor housing.

A particularly advantageous embodiment, however, provides that the Damper channel arranged in a usable in the compressor housing part is.

This part could be both the inlet channel and the damper channel include. It is particularly favorable, however, if that in the compressor housing usable part in the inlet channel in the compressor housing used is.

An expedient with regard to the constructive solution embodiment provides that the insertable part comprises a damper tube and a holder, with which the damper tube is fixable in the compressor housing.

This solution is structurally favorable insofar as the damper tube and The holder can be subsequently inserted into the inlet channel.

A particularly appropriate fixation of the damper tube and the holder in the inlet channel thereby provides a positive fixation of the holder in the Inlet channel.

With regard to the further design of the screw compressor were in Connection with the previous explanation of the individual embodiments no details provided. This is what a particularly favorable one looks like Embodiment before that the compressor housing includes a control slide, and that the inlet disposed in the control slide and slidable with this is.

In this solution of the screw compressor according to the invention this is in terms the available compression adjustable and simultaneously with the controllability It is also possible to use the subcooling circuit independently of the To operate the scheme effectively.

With regard to the formation of the connection between the inlet with the Inlet channel, the most diverse solutions are conceivable. For example It is conceivable in the control slide and in the compressor housing each other in all Provide positions of the control slide overlapping sections over which the inlet channel can be guided in the control slide. A structurally advantageous solution provides that the inlet in the control slide over a variable length portion of the intake port to the outer port connected is.

It is particularly advantageous if the variable-length section of the inlet channel is formed telescopically.

An expedient embodiment of such a variable-length section the inlet channel provides that the variable-length portion of the inlet channel is formed by an insertable into a receiving channel connecting tube.

Regarding the length of the damper channel were related to the previous explanation of the solution according to the invention no further details made. Thus, a particularly favorable solution that the damper channel has a length which is about one quarter of the wavelength of dampening pressure swing or an odd multiple of the same equivalent.

The wavelength of the pressure oscillations to be damped is thereby eliminated determine a fundamental frequency of the pressure oscillations, where the fundamental frequency the pressure oscillations the product of the speed of the Screw rotor and the number of screw combs same results.

The damper channel is particularly efficient if it is connected to a first Mouth opening in between the outer terminal and the first Mouth opening lying first volume opens, so that the first Mouth opening represents a so-called "open end" of the damper channel, on which a reflection of the pressure oscillations at the so-called "open end" takes place.

Furthermore, it is advantageously provided that the damper channel with a second orifice in a lying between this and the inlet second volume opens, so that a at the second mouth opening so-called open end exists.

To best possible conditions for a reflection on the so-called To obtain "open end" is preferably provided that the transition from one of the mouth openings in the respective volume a cross-sectional area jump is present. This cross-sectional area should be as large as possible his. It is preferably provided that the cross-sectional area jump at least a factor of 1.5.

To a propagation of pressure oscillations or pulsations in the piping system of the subcooling cycle or largely increased avoid, it is preferably provided that between the first Orifice and the outer terminal lying first volume in the Compressor housing is located.

Preferably, the first volume is in an inlet channel section of the through the compressor housing guided inlet channel.

Furthermore, it is also with regard to an optimal damping of the pressure oscillations or pulsations advantageous if that between the second Mouth opening and the inlet second volume also in the Compressor housing is located.

Conveniently, the second volume also extends in the Damper channel receiving inlet channel section.

In a further advantageous embodiment is in connection for the Subcooling cycle associated with an expansion volume.

This expansion volume can also still in the inlet channel and in the Be provided compressor housing.

For reasons of space, however, it has proven to be advantageous if the Expansion volume near the outer connection for the subcooling circuit is provided in the piping system of the subcooling circuit.

In connection with the previous explanation of the invention The solution was not discussed in more detail in that Damper duct oil can accumulate, reducing the effect of the damper channel is reduced.

Such oil accumulation in the damper channel can not be effective Undercooling, under certain circumstances but also effective Subcooling cycle done.

For this reason, a particularly advantageous solution provides that the Piping system is connected to an oil drain, which ensures that Oil, especially near the damper channel collecting oil from the Line system is removed.

It is particularly advantageous if the oil discharge in the inlet channel opens, in particular, if it is provided in this damper channel, there so that the possibility exists, as close as possible to the location of the damper channel To avoid oil accumulation.

A particularly favorable solution provides that the oil drain in the first Volume opens. With this arrangement of oil emptying there is the possibility especially in the area of the first volume avoid oil accumulation and thus to maintain the effect of the damper channel.

In particular, it is advantageous that the effect of the damper channel is ensured by facing the outer inlet thereof at the Mouth opening no oil accumulations form.

Further features and advantages of the invention are the subject of the following Description and the drawings of some embodiments.

Fig. 1

eine Anordnung eines erfindungsgemäßen Schraubenverdichters in einem Kühlkreislauf mit Unterkühlungskreislauf;

Fig. 2

einen Längsschnitt durch ein erstes Ausführungsbeispiels eines erfindungsgemäßen Schraubenverdichters;

Fig. 3

eine vergrößerte Darstellung des Längsschnitts gemäß Fig. 2 im Bereich eines Regelschiebers;

Fig. 4

eine vergrößerte ausschnittsweise Darstellung eines Schnitts durch das Verdichtergehäuse des ersten Ausführungsbeispiels im Bereich eines auf einen äußeren Anschluß folgenden Einlaßkanals und

Fig. 5

einen Schnitt ähnlich Fig. 4 bei einem zweiten Ausführungsbeispiel eines erfindungsgemäßen Schraubenverdichters.

In the drawing show:

Fig. 1

an arrangement of a screw compressor according to the invention in a cooling circuit with subcooling circuit;

Fig. 2

a longitudinal section through a first embodiment of a screw compressor according to the invention;

Fig. 3

an enlarged view of the longitudinal section of Figure 2 in the region of a control slide.

Fig. 4

an enlarged fragmentary view of a section through the compressor housing of the first embodiment in the region of an outer port following an inlet port and

Fig. 5

a section similar to FIG. 4 in a second embodiment of a screw compressor according to the invention.

A first embodiment of a screw compressor according to the invention, shown in Fig. 1 comprises a designated as a whole with / 10 Compressor housing, to which a suction port 12 and a pressure port 14 are provided, sucked at the suction port 12 refrigerant and on Pressure port 14 compressed refrigerant is discharged.

The discharged at the pressure port 14 compressed refrigerant is first fed to a condenser 16 and passes from the condenser 16 into a Latch 18 for liquid refrigerant. After the buffer 18 the liquefied refrigerant flows through a check valve 20 and a Branch 22, from which a cooling circuit 24 on to an expansion valve 26, and an evaporator 28 leads, and then back from the evaporator 28 to the suction port 12th

In addition, a subcooling circuit 30 is provided to the cooling circuit 24, which branches off from the cooling circuit 24 at the junction 22 and an expansion valve 32 through which a portion of the mass flow of the initially compressed by the screw compressor refrigerant the cooling circuit 24 is expanded and fed to a subcooler 34, flows through the subcooler 34 and then one on the compressor housing 10th provided connection 40 for the subcooling circuit 30 is supplied.

At the same time, the refrigerant circulated in the cooling circuit 24 flows through the branch 22 and the expansion valve 26 also the subcooler 34th and experiences in the subcooler 34 a further subcooling before its expansion in the expansion valve 26, which causes that with the additional subcooling circuit 30 in the cooling circuit 24, the cooling capacity and the coefficient of performance improved, with the power requirement of the screw compressor only slightly increased.

A first embodiment of a screw compressor according to the invention comprises, as shown in detail in FIGS. 2 and 3, in the compressor housing 10 provided screw rotor bores 48, in which intermeshing Screw rotor 50 are rotatably disposed, wherein the Schraubenläuferbohrungen 48 from a suction-side refrigerant inlet 52 to extend to a pressure-side refrigerant outlet 54 and the intermeshing Screw runner 50 the refrigerant in the area of the refrigerant inlet 52 suction, in the course of the way to the refrigerant outlet 54th compact and deliver as a compressed refrigerant at the refrigerant outlet 54. Further, a recess 56 is provided in the compressor housing 10, in which a control slide 58 is movable in a direction 60, which runs parallel to a rotation axis 62 of the screw rotor 50.

The control slide 58 forms with the screw rotors 50 facing Slider wall 64 a wall side of the Schraubenläuferbohrungen 48, which by the displacement in the direction 60 creates the possibility that by to regulate the screws runner 50 achievable compression. In the in Fig. 2 illustrated position, the entire slide wall 64 extends along the Screw rotor 50, and creates the possibility that the screw rotor 50th over its entire length in the direction of its axis of rotation 62 for compression Contribute the refrigerant while at the position shown in Fig. 3 of the Control slide 58 this is moved so far that only a portion the slider wall 64 is adjacent to the screw rotor 50 and thus the Screw rotor 50 only over a part of its length for compression of the Contribute refrigerant, namely with the part which on the slide wall 64th adjacent, while by the displacement of the control slide 58 in Connection to the refrigerant inlet 52 a space 66 between this and a suction-side edge 68 of the control slide 58 forms, which the to the Free space 66 adjacent region of the screw rotor 50 with respect to Compaction of the refrigerant makes ineffective.

The control slide 58 is actuatable by means of an adjusting device 70, which, for example, can be designed as in the European Patent Application 1,072,796.

The adjusting device 70 may also be designed differently and For example, be controlled externally continuously.

To the subcooling circuit 30 in all positions of the control slide 58th To operate effectively, it is necessary that in all positions of the Regulator 58 coming from the subcooling circuit 30 and by the screw compressor to be sucked refrigerant one of Screw rotors 50 and the screw rotor bores 48 and the Slider wall 64 limited compression space 72 is supplied, in which the refrigerant is at a pressure level higher than the pressure level in the refrigerant inlet 52 and lower than the pressure level in the refrigerant outlet 54th

For this reason, in the control slide 58, an inlet 80 is provided for to be sucked from the subcooling circuit 30 via a line system 78 refrigerant in the form of a slide wall 64 passing through hole, wherein an opening into the compression chamber 72 inlet opening 82 is always so that above this always an opposite to the refrigerant inlet 52 and the refrigerant outlet 54 closed compression chamber 72 is or the inlet port 82 is closed by a screw comb 84 _x .

As shown in Fig. 3, closes in the drawn in Fig. 3 position of the screw rotor 50 of the screw comb 84 _x just the inlet port 82, while an initially still open to the refrigerant inlet 52 future space 72 'forms, the further rotation of the screw rotor 50th is closed relative to the refrigerant inlet 50 by the next following screw comb 84 _x-1 and then comes to rest over the inlet port 82 so that then there is a connection between the inlet 80 and then closed compression space and can flow through the inlet 80 refrigerant in this compression space ,

Preferably, the inlet port 82 is located so that in the first of the Schraubenkämmen 84 opposite the refrigerant inlet 82 completed Compaction space 72 opens.

In the illustrated embodiment, the inlet 80 is in communication with a direction 60 in the control slide 58 extending central receiving channel 90, which has an opening 92 on one side, about which in this one held on the compressor housing 10 connecting pipe 94 protrudes, wherein between the central receiving channel 90th and the connecting pipe 94, a seal 96 is provided and the Connecting tube 94 has a length such that this in any position the control slide 58 sealed by the seal 96 in the central Receiving channel 90 protrudes, without the displaceability of the control slide 58 between the intended positions for regulation.

The connecting tube 94 is connected to a running in the compressor housing 10 Housing channel 98 is connected, which to the terminal 40 on the compressor housing 10 is guided.

A part of the conduit system 78 forming inlet channel 100 between the Terminal 40 and the inlet 80 in the compressor housing 10 is thus formed through the housing channel 98, a running in the connecting pipe 94 channel 102 and the central receiving channel 90 in the control slide 58, from which the inlet 80 branches off, wherein the connecting pipe 94 and the Receiving passage 90 a variable length portion 104 of the intake port 100th form.

Since - as already described - via the inlet opening 82 always the screw combs 84 of the screw rotor 52 run away and thus always again newly formed compression chamber 72 is connected to the inlet 80 arise in the inlet channel 100 pressure oscillations or pulsations with a Fundamental frequency, which is the speed of the driven by a motor 110 Screwdriver 50 multiplied by the number of screw combs 84 of the screw rotor 50 results.

To dampen such pressure oscillations or pulsations is in the inlet channel 100, preferably in a directly to the outer terminal 40, formed by a connecting flange 112 and a pipe connection 114, subsequent inlet channel section 116 of the inlet channel 100, in particular the housing channel 98, a damper channel 120 is provided, which is in a damper tube 122 which inserted into the inlet channel section 116 is.

The damper channel 120 in the damper tube 122 extends from a first orifice 124 to a second orifice 126 with a preferably uniform cross-section, wherein the mouth openings 124 and 126 have cross-sectional areas that are smaller than the Cross-sectional areas of the damper tube 122 surrounding the inlet channel section 116, so that starting at both mouth openings 124 and 126 from the damper channel 120 a jump in the cross section to a larger cross-sectional area by a factor of at least 1.5.

Preferably, the damper tube 122 has a smaller cross-section than the inlet channel section 116 and is provided with a holder 130 in the inlet channel section 116 held.

For example, the holder 130 is formed as a retaining ring, which with a External thread 127 is provided which in an internal thread 128 of the inlet channel section 116 engages, so that a positive connection between the holder 130 and the compressor housing 10 can be produced.

The holder 130 and the damper tube 122 thereby share the inlet channel section 116 in two out of the damper tube 122 volumes, namely a first volume 132 and a second volume 134.

The first volume 132 is between the port 40 and the first Orifice 124, wherein the first volume is still around the Damper tube 122 may extend around to the holder 130 around. The second Volume 134 is between the second orifice 126 and the inlet 80, wherein the second volume 134 is still around the damper tube 122nd can extend around to the holder 130.

In the solution according to the invention, the length of the damper channel is now 120 in the damper tube 122 dimensioned so that they are of the order of a Quarter or an integer multiple of a quarter, the wavelength of one at the fundamental frequency forming pressure oscillation or pulsation in the Refrigerant corresponds, so that in particular by the combination of Damper channel 120 with the first volume 132 and the second volume 134 the pressure oscillations or pulsations are damped.

For example, with such a solution, a reduction of the pressure differences between peaks of pulsations from 5 bar to pressure differences between peaks of pulsations of 1 bar possible.

With the solution according to the invention, there is the possibility of the pressure oscillations or pulsations already in the compressor housing 10 worth mentioning to reduce and thus avoid that this in the compressor housing 10 wegführend piping system of the subcooling circuit 30th reproduce and lead to unwanted vibrations in this.

The damper channel 120 is effective regardless of whether he subcooling circuit 30 is effective or not.

In particular, there is no effective subcooling circuit 30 due to the in the line system 78 standing refrigerant also in Increased extent, the tendency that pressure oscillations or pulsations in the outside of the compressor housing 10 extending piping system of the subcooling circuit 30, so that the damper channel 120 also when not effective subcooling circuit 30 for damping of pressure oscillations or pulsations contributes significantly.

In order to prevent that in the inlet channel 100 in not effective Subcooling circuit 30 oil accumulates and the effectiveness of the damper channel 120 is affected by this at least partially with oil vollläuft, the inlet channel 100 - as shown in Fig. 1 - an oil drain 136 assigned, which on the one hand via an oil drainage channel 137, shown in Fig. 4, in the inlet channel 100 in the region of the inlet channel section 116, preferably in the first volume 132 thereof, and on the other hand with the suction port 12, preferably with the suction end of the Cooling circuit 24, is connected.

Furthermore, the oil drainage 136 also includes a valve 138, which, for example can be activated at intervals when the subcooling circuit 30 is not active is at these intervals in the inlet channel 100, in particular in the first Volume 132 of the same, to dissipate collecting oil.

The oil discharge 136 does not necessarily have to be effective even with a subcooling cycle 30 work, since with effective subcooling circuit 30 in usually due to the refrigerant flowing through the inlet port 100 there collecting oil is supplied to the compression chambers 72.

But it is also possible during the effective Unterkühlungskreislaufs 30th To operate the oil drain 136, as a precaution, any type of oil accumulation in the inlet channel 100, in particular in the damper channel 120th receiving inlet portion 116 to avoid.

In a second embodiment shown in Fig. 5, in addition to the pressure channel 120, in a directly to the terminal 40 subsequent section 140 of a piping system of the subcooling circuit 30 nor an expansion volume 142 is provided which the Possibility, still out of the compressor housing 10 out in the Section 140 of the piping system propagating pressure swing or To further damp pulsations and thus their effect on the piping system continue to reduce.

Otherwise, the second embodiment is formed in the same way as the first embodiment, so that the comments on this is fully incorporated by reference.

Claims (25)

Comprising screw compressor
two screw rotors (50) arranged in a compressor housing (10) in screw rotor bores (48) which compress a refrigerant entering at a refrigerant inlet (52) and exit at a refrigerant outlet (54) and an inlet (10) provided in said compressor housing (10) 80) for refrigerant coming from a subcooling circuit (30), in a conduit system (78) to the inlet (80), the inlet (80) being arranged to be engaged by the screw rotors (50) and screw rotor bores (48). enclosed compaction spaces (72) opens,
characterized in that the damper duct (120), which is assigned to the inlet in the duct system (78), is provided upstream of which there is refrigerant from the supercooling circuit (30). Screw compressor according to Claim 1, characterized in that the damper channel (120) is arranged in the compressor housing (10). Screw compressor according to claim 2, characterized in that the damper channel (120) is formed in a housing section receiving the screw rotor bores (48). Screw compressor according to one of the preceding claims,
characterized in that an inlet passage (100) extending through the compressor housing (10) is provided as part of the conduit system (78) leading from an external port (40) connected to the subcooling circuit (30) to the compressor housing (10) to the inlet (80) leads, and that the damper channel (120) in the inlet channel (100) is arranged. Screw compressor according to one of the preceding claims,
characterized in that the damper channel (120) in a in the compressor housing (10) insertable part (122) is arranged. Screw compressor according to Claim 5, characterized in that the part (122) which can be inserted into the compressor housing (10) can be inserted into the inlet channel (100) in the compressor housing (10). Screw compressor according to claim 5 or 6, characterized in that the insertable part comprises a damper tube (122) and a holder (130) with which the damper tube (122) in the compressor housing (10) can be fixed. Screw compressor according to one of the preceding claims,
characterized in that the compressor housing (10) comprises a control slide (58), and that the inlet (80) in the control slide (58) is arranged and displaceable with this. Screw compressor according to Claim 8, characterized in that the inlet (80) in the control slide (58) is connected to the outer connection (40) via a variable-length section (104) of the inlet channel (100). Screw compressor according to claim 9, characterized in that the variable-length portion (104) of the inlet channel (100) is telescopic. Screw compressor according to Claim 9 or 10, characterized in that the variable-length section (104) of the inlet channel (100) is formed by a connecting tube (94) which can be inserted into a receiving channel (90). Screw compressor according to one of the preceding claims,
characterized in that the damper channel (120) has a length which corresponds to approximately one quarter of the wavelength of the pressure vibrations to be damped or an odd multiple thereof. Screw compressor according to one of the preceding claims,
characterized in that the damper channel (120) opens with a first orifice (124) in a between the outer terminal (40) and the first orifice (124) lying first volume (132). Screw compressor according to one of the preceding claims,
characterized in that the damper channel (120) opens with a second orifice (126) in a between this and the inlet (80) lying second volume (134). Screw compressor according to one of claims 13 or 14, characterized in that there is a cross-sectional gap in the transition from one of the mouth openings (124, 126) into the respective volume (132, 134). Screw compressor according to claim 15, characterized in that the cross-sectional area jump is at least a factor of 1.5. Screw compressor according to one of claims 13 to 16, characterized in that the first volume (132) lying between the first orifice (124) and the outer port (40) lies in the compressor housing (10). Screw compressor according to claim 17, characterized in that the first volume (132) lies in an inlet channel section (116). Screw compressor according to one of claims 14 to 18, characterized in that the second volume (134) lying between the second orifice (126) and the inlet (80) lies in the compressor casing (10). Screw compressor according to claim 19, characterized in that the second volume (134) lies in the inlet channel section (116). Screw compressor according to one of the preceding claims,
characterized in that the outer terminal (40) is associated with an expansion volume (142). Screw compressor according to one of the preceding claims,
characterized in that the conduit system (78) is connected to an oil drain (136). Screw compressor according to claim 22, characterized in that the oil discharge (136) opens into the inlet channel (100). Screw compressor according to claim 23, characterized in that the oil discharge (136) opens into the inlet channel section (116) receiving the damper channel (120). Screw compressor according to claim 24, characterized in that the oil discharge (136) opens into the first volume (132).

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