EP3633192A1 - Coolant compressor - Google Patents

Abstract

Refrigerant compressor (1) comprising an electric drive unit (2), a piston-cylinder unit (3) which can be driven by means of the drive unit (2) for the cyclical compression of refrigerant and at least one soundproofing unit (4) through which refrigerant can flow and which has at least one damping chamber Made of a thermoplastic material, the at least one sound-absorbing unit (4) being connected to the piston-cylinder unit (3) in order to exchange refrigerant between the sound-absorbing unit (4) and the piston-cylinder unit (3) enable. It is proposed that the at least one sound absorbing unit (4) has a functional surface (11) at least in sections, the functional surface (11) being designed such that an emissivity of a section of the sound absorbing unit (4) having the functional surface (11) is smaller than 0.7, preferably less than 0.5, particularly preferably less than 0.1.

Description

FIELD OF THE INVENTION

The present invention relates to a refrigerant compressor comprising an electric drive unit, a piston-cylinder unit which can be driven by the drive unit for the cyclical compression of refrigerant and at least one refrigerant-permeable, at least one damping chamber having a silencer unit made of a thermoplastic, the at least one silencer -The unit is connected to the piston-cylinder unit in order to enable an exchange of refrigerant between the soundproofing unit and the piston-cylinder unit.

STATE OF THE ART

Hermetically sealed refrigerant compressors have been known for a long time and are mainly used in refrigerators or shelves. The refrigerant process as such has also been known for a long time. Refrigerant is heated by energy absorption from the room to be cooled in an evaporator and finally overheated and pumped to a higher pressure level by means of the refrigerant compressor with a piston-cylinder unit, where it emits heat via a condenser and a throttle, in which a pressure reduction and the cooling of the refrigerant takes place, is conveyed back into the evaporator.

The (gaseous) refrigerant is drawn in via a suction pipe coming directly from the evaporator during a suction stroke of the piston-cylinder unit. The suction pipe opens in known hermetically encapsulated refrigerant compressors, as a rule, into the hermetically encapsulated compressor housing - usually near an inlet of a suction muffler, from where the refrigerant flows into the suction muffler and through this to an intake valve of the piston-cylinder unit. This means that the suction muffler is located in front of the piston-cylinder unit when viewed in the direction of flow and serves primarily to keep the noise level of the refrigerant compressor as low as possible during the intake process.

Furthermore, there is usually a pressure silencer, seen in the direction of flow, behind the piston-cylinder unit, which serves to keep the noise level of the refrigerant compressor as low as possible when the compressed refrigerant flows out.

Opportunities for improving the efficiency of the refrigerant compressor are, in particular, lowering the temperature of the refrigerant at the start of the compression process. Every lowering of the intake temperature of the refrigerant into the cylinder of the piston-cylinder unit results in a reduction in the technical work required for the compression process.

In the case of known hermetically encapsulated refrigerant compressors, the refrigerant heats up considerably on its way through the suction muffler to the piston-cylinder unit. This is due to the heating of the interior of the compressor housing, which mainly takes place due to the compressed refrigerant discharged in the pressure silencer. The compressed refrigerant discharged in the pressure silencer has temperatures of up to 180 ° C and thus represents a significant heat source. This leads to heating of the interior of the compressor housing and more Follow to heat transfer to the refrigerant in the suction muffler.

With regard to the engine cooling, too, heating of the interior of the compressor housing is undesirable because of the compressed refrigerant in the pressure silencer.

OBJECT OF THE INVENTION

It is therefore an object of the invention to provide a refrigerant compressor which avoids the disadvantages mentioned above. Temperature increases inside the compressor housing should be reduced. In particular, the refrigerant temperature should be kept as low as possible at the beginning of the compression process in order to increase the efficiency.

PRESENTATION OF THE INVENTION

In a refrigerant compressor, the object stated at the outset is comprised of an electric drive unit, a piston-cylinder unit which can be driven by means of the drive unit for the cyclical compression of refrigerant and at least one soundproofing unit made of a thermoplastic material and having at least one damping chamber through which refrigerant can flow,
wherein the at least one silencing unit is connected to the piston-cylinder unit in order to enable an exchange of refrigerant between the silencing unit and the piston-cylinder unit, solved according to the invention in that the at least one silencing unit has a functional surface at least in sections has, wherein the functional surface is designed such that a The emissivity of a section of the sound damping unit having the functional surface is less than 0.7, preferably less than 0.5, particularly preferably less than 0.1.

The functional surface, which is present at least in sections, reduces the heat radiation and / or heat absorption by radiation on the at least one soundproofing unit. By using a functional surface, the at least one sound absorption unit has a reduced emissivity in those areas in which the functional surface is present.

The emissivity of the at least one sound absorption unit indicates how much radiation the at least one sound absorption unit emits in comparison to an ideal heat radiator, a black body. I.e. the at least one sound absorption unit has a reduced heat radiation and / or heat absorption by radiation in those areas in which the functional surface is present compared to surface sections without a functional surface. This reduces the temperature inside a compressor housing. This means that the refrigerant compressor according to the invention has a better efficiency.

The functional surface can either be formed on an outer surface of the at least one sound-absorbing unit, the outer surface facing the interior of the compressor housing, or on an inner surface of the at least one sound-absorbing unit, the inner surface on the inside of the at least one sound-absorbing unit , in particular facing the at least one damping chamber. Of course, radiation emission and absorption correspond to each other at a given wavelength. This means that the functional surface, in addition to reduced heat radiation, also leads to reduced heat absorption.

It would be conceivable that the at least one sound absorption unit is manufactured using an injection molding process. Such a manufacturing process is characterized by its particular economy.

Furthermore, it would be conceivable that the functional surface is polished in order to achieve a particularly low emissivity.

It is preferably provided in the refrigerant compressor according to the invention that the thermoplastic comprises additives, for example aluminum and / or chromium.

In complex tests, it was found that it may be sufficient to add additives to the thermoplastic in order to achieve the formation of a functional surface with a correspondingly low emission and absorption level of the at least one sound absorption unit. I.e. in such a case, the functional surface is at least partially formed by a surface section of a solid material of the at least one silencing unit, and no additional coating is necessary (although such is also not excluded). It would also be conceivable for the additives to be present only in areas of the solid material of the sound-absorbing unit that are close to the surface.

In other words, the task stated at the outset is achieved with a refrigerant compressor comprising an electric drive unit, one which can be driven by means of the drive unit Piston-cylinder unit for the cyclical compression of refrigerant and at least one sound-absorbing unit made of a thermoplastic material, through which refrigerant can flow and at least one damping chamber, wherein the at least one sound-absorbing unit is connected to the piston-cylinder unit in order to exchange To enable refrigerant between the soundproofing unit and the piston-cylinder unit, solved according to the invention in that the thermoplastic comprises additives, such as aluminum and / or chromium, the heat radiation of a soundproofing unit made of thermoplastic with additives compared to a soundproofing unit made of thermoplastic is reduced without additives.

The heat radiation or absorption can additionally be reduced if the surface of the solid material of the at least one soundproofing unit made of thermoplastic material is polished.

It would be conceivable that the functional surface is only formed by polishing. I.e. In this case, the functional surface is also formed when the thermoplastic does not have any additives.

It is preferably provided in the refrigerant compressor according to the invention that the functional surface is designed as a metallic layer. A metallic layer as a functional surface is characterized by a low emission coefficient, especially when the metallic layer is polished.

However, it would also be conceivable for the functional surface to be preferably a non-metallic layer is designed as a ceramic layer with a low emission coefficient.

In a preferred embodiment variant of the refrigerant compressor according to the invention, it is provided that the at least one soundproofing unit is completely encased in the metallic layer. As a result, the temperature within the compressor housing is significantly reduced, since the heat absorption or heat emission of the at least one soundproofing unit is reduced.

A sheathing of the at least one soundproofing unit by the metallic layer is particularly simple and inexpensive to manufacture.

Of course, the metallic layer can also be arranged on the inner surface facing the interior of the at least one sound absorption unit.

In a preferred embodiment variant of the refrigerant compressor according to the invention it is provided that the metallic layer contains chromium and / or aluminum. Both chrome and aluminum, especially with a polished surface, have low emissivity and absorption levels, which is why they are excellent components of the metallic layer.

It would be conceivable for the chromium and / or aluminum-containing layer to have an emissivity between 0.1 and 0.02 in the polished state.

It would also be conceivable for the metallic layer to comprise other constituents in addition to chrome and / or aluminum. It is preferably provided in the refrigerant compressor according to the invention that the metallic layer is designed as a metallic foil. The metallic layer in the form of a metallic foil is characterized by a particularly good reduction in heat radiation and heat absorption and is easy to apply.

It is preferably provided in the refrigerant compressor according to the invention that the at least one sound absorption unit can be obtained by back-injection of the metallic foil, i.e. the metallic foil is back-injected with the thermoplastic. First, the film is fed to an injection molding tool. The thermoplastic material is then injected into the injection mold, the thermoplastic material and the film joining together. It is advantageous that the back molding can be fully automated and that no adhesive is required for the connection between the thermoplastic and the film.

In a preferred embodiment variant of the refrigerant compressor according to the invention it is provided that the metallic layer is applied and / or varnished and / or glued and / or galvanized onto the at least one sound absorption unit. When applying and / or painting and / or gluing and / or electroplating, the metallic layer is applied in a simple manner on the at least one soundproofing unit. These types of applications are characterized by simple handling and good economy.

Electroplating in particular can be automated easily and the coating produced by means of electroplating is characterized by low costs and fast producibility.

It is preferably provided in the refrigerant compressor according to the invention that the at least one sound damping unit or one of the sound damping units is designed as a suction sound damper arranged in the flow direction upstream of the piston-cylinder unit.

Since the at least one suction muffler is arranged inside the compressor housing in the flow direction in front of the piston-cylinder unit, the functional surface must have a low degree of absorption. This is because otherwise the refrigerant inside the suction muffler due to the high temperatures inside the compressor housing - i.a. due to the compressed refrigerant discharged in the pressure pipe - is present. In this case, the functional surface is thus preferably formed on the outer surface of the suction muffler facing the interior of the compressor housing and leads to an improved efficiency of the refrigerant compressor according to the invention, since the temperature of the refrigerant inside the suction muffler is not increased by a higher temperature inside the compressor housing. because the heat radiation from the functional surface is essentially reflected back into the compressor housing.

Of course, in the case of the suction muffler, the functional surface can also be formed on the inner surface facing the interior of the suction muffler and thereby lead to an improved efficiency of the refrigerant compressor according to the invention.

In a preferred embodiment variant of the refrigerant compressor according to the invention, it is provided that the at least one silencing unit or at least one of the silencing units behind as in the flow direction the piston-cylinder unit arranged pressure silencer is formed.

Since the at least one pressure silencer, preferably inside the compressor housing, is arranged in the flow direction behind the piston-cylinder unit, the functional surface must have a low emissivity. This is because the refrigerant after the piston-cylinder unit enters the at least one pressure silencer due to the compression at a high temperature and heats it up accordingly. In this case, the functional surface is preferably formed on the inner surface facing the interior of the pressure muffler and leads to an improved efficiency of the refrigerant compressor according to the invention, since temperature increases inside the compressor housing are reduced because the heat radiation of the refrigerant from the functional surface essentially into the interior of the Pressure silencer is reflected back.

Of course, in the case of the pressure muffler, the functional surface can also be formed on the outer surface of the pressure muffler facing the interior of the compressor housing and thereby lead to an improved efficiency of the refrigerant compressor according to the invention.

It would be conceivable for other parts of the refrigerant compressor according to the invention, such as parts of the piston-cylinder unit, to be provided with a corresponding functional surface with a low emissivity.

BRIEF DESCRIPTION OF THE FIGURES

The invention will now be explained in more detail on the basis of exemplary embodiments. The drawings are exemplary and are intended to illustrate the inventive concept, but in no way to narrow it down or even reproduce it conclusively.

Fig. 1

eine Schnittansicht eines bekannten Kältemittelverdichters,

Fig. 2

eine Frontansicht eines mit einer Funktionsoberfläche versehenen Saugschalldämpfers,

Fig. 3

eine Schnittansicht des Saugschalldämpfers aus Fig. 2 gemäß der in Fig. 2 eingezeichneten Schnittlinie A-A,

Fig. 4

eine Frontansicht eines mit einer Funktionsoberfläche versehenen Druckschalldämpfers, und

Fig. 5

eine Schnittansicht des Druckschalldämpfers aus Fig. 4 gemäß der in Fig. 4 eingezeichneten Schnittlinie B-B.

It shows:

Fig. 1

1 shows a sectional view of a known refrigerant compressor,

Fig. 2

2 shows a front view of a suction muffler provided with a functional surface,

Fig. 3

a sectional view of the suction muffler Fig. 2 according to the in Fig. 2 drawn section line AA,

Fig. 4

a front view of a pressure muffler provided with a functional surface, and

Fig. 5

a sectional view of the pressure muffler Fig. 4 according to the in Fig. 4 drawn section line BB.

WAYS OF CARRYING OUT THE INVENTION

The Fig. 1 shows a sectional view of a known refrigerant compressor 1. The refrigerant compressor 1 comprises a compressor housing 8, a drive unit 2, a piston-cylinder unit 3, in which the cyclical compression of a refrigerant takes place, and at least one sound absorption unit 4.

The at least one silencing unit 4 can be a suction silencer 6 and / or one Act pressure silencer 7. The suction muffler 6 is arranged in front of the piston-cylinder unit 3 in the flow direction of the refrigerant, while the pressure muffler 7 is located behind the piston-cylinder unit 3 in the flow direction of the refrigerant.

On the way between the entry of the refrigerant into the compressor housing 8 and the intake valve of the piston-cylinder unit 3, as already mentioned, the refrigerant is heated undesirably. This is due to the heating of the interior of the compressor housing 8, which among other things. due to the compressed refrigerant discharged in the pressure silencer 7. The compressed refrigerant discharged in the pressure silencer 7 sometimes has temperatures of up to 180 ° C. and thus represents a significant heat source. This leads to heating of the interior of the compressor housing 8 and subsequently to heat transfer to the refrigerant located in the suction silencer 6 .

Therefore, both in 2 and 3 shown suction muffler 6 as well as in 4 and 5 shown pressure silencer 7 with a functional surface 11, which is preferably designed as a metallic layer 5, provided.

Fig. 2 shows a front view of the suction muffler 6 having the functional surface 11, while Fig. 3 a sectional view of the suction muffler 6 from Fig. 2 according to the in Fig. 2 drawn section line AA represents. The suction muffler 6 has at least one damping chamber 9, but preferably a plurality of damping chambers 9. In Fig. 3 it can be seen that the suction muffler 6 is completely covered with the metallic layer 5.

The metallic layer 5 preferably contains aluminum and is particularly preferably designed as a film which is applied to the suction muffler 6. The metallic layer 5 on the suction muffler 6 is polished in the exemplary embodiment shown, which is why it has a particularly well reflecting surface. The metallic layer 5 thus has a low degree of absorption, which is why the refrigerant inside the suction muffler 6 is hardly or not at all heated by the higher temperatures which can prevail inside the compressor housing 8.

Fig. 4 shows a front view of the pressure muffler 7 having the functional surface 11, while Fig. 5 a sectional view of the pressure muffler 7 from Fig. 4 according to the in Fig. 4 drawn section line BB represents. The pressure silencer 7 has at least one damping chamber 10, but preferably a plurality of damping chambers 10. In Fig. 5 it can be seen that the pressure silencer 7 is completely encased in the metallic layer 5.

The metallic layer 5 preferably contains aluminum and is particularly preferably in the form of a film which is applied to the pressure silencer 7. The metallic layer 5 on the pressure silencer 7 is polished in the exemplary embodiment shown, which is why it has a particularly well reflecting surface. The metallic layer 5 thus has a low emissivity, which is why the high temperature of the compressed refrigerant is hardly or not at all transferred to the interior of the compressor housing 8. I.e. the metallic layer 5 on the at least one pressure silencer 7 reduces or prevents heat radiation.

Of course, other parts of the refrigerant compressor 1 according to the invention, such as parts of the piston-cylinder unit 3 and various pipes, can also be provided with a functional surface 11, in particular with a metallic layer 5.

With the aid of the refrigerant compressor 1 according to the invention, temperature increases in the interior of the compressor housing 8 are thus reduced, as a result of which the refrigerant temperature in particular is kept as low as possible at the beginning of the compression process and thus necessarily also when the cylinder-piston unit 3 is drawn into the cylinder. The consequence of this is that the refrigerant compressor 1 according to the invention has a better efficiency than a known refrigerant compressor 1.

REFERENCE SIGN LIST

1

Refrigerant compressors

2nd

Drive unit

3rd

Piston-cylinder unit

4th

Sound absorption unit

5

Metallic layer

6

Suction silencer

7

Pressure silencer

8th

Compressor housing

9

Damping chamber of the suction muffler

10th

Damping chamber of the pressure silencer

11

Functional interface

Claims (10)

Refrigerant compressor (1) comprising an electric drive unit (2), a piston-cylinder unit (3) which can be driven by means of the drive unit (2) for the cyclical compression of refrigerant and at least one soundproofing unit (4) through which refrigerant can flow and which has at least one damping chamber from a thermoplastic,
wherein the at least one silencing unit (4) is connected to the piston-cylinder unit (3) in order to enable an exchange of refrigerant between the silencing unit (4) and the piston-cylinder unit (3),
characterized in that
the at least one sound damping unit (4) has a functional surface (11) at least in sections, the functional surface (11) being designed such that an emissivity of a section of the sound damping unit (4) having the functional surface (11) is less than 0.7, is preferably less than 0.5, particularly preferably less than 0.1. Refrigerant compressor according to claim 1, characterized in that the thermoplastic comprises additives, for example aluminum and / or chromium. Refrigerant compressor (1) according to one of claims 1 to 2, characterized in that the functional surface (11) is designed as a metallic layer (5). Refrigerant compressor (1) according to claim 3, characterized in that the at least one sound absorption unit (4) is completely encased by the metallic layer (5). Refrigerant compressor (1) according to one of claims 3 to 4, characterized in that the metallic layer (5) contains chromium and / or aluminum. Refrigerant compressor (1) according to one of claims 3 to 5, characterized in that the metallic layer (5) is designed as a metallic foil. Refrigerant compressor (1) according to claim 6, characterized in that the at least one sound absorption unit (4) can be obtained by back-injection of the metallic foil. Refrigerant compressor (1) according to one of claims 3 to 6, characterized in that the metallic layer (5) is applied and / or varnished and / or glued and / or galvanized onto the at least one sound-absorbing unit (4). Refrigerant compressor (1) according to one of claims 1 to 8, characterized in that the at least one sound damping unit (4) or one of the sound damping units (4) is arranged in the flow direction upstream of the piston-cylinder unit (3) suction silencer ( 6) is formed. Refrigerant compressor (1) according to one of claims 1 to 9, characterized in that the at least one sound damping unit (4) or at least one of the sound damping units (4) as a pressure silencer arranged behind the piston-cylinder unit (3) in the flow direction (7) is formed.

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