WO2021160797A1

WO2021160797A1 - A flow guide for a reciprocating-type compressor of a cooling system and a reciprocating-type compressor for a cooling system comprising said flow guide

Info

Publication number: WO2021160797A1
Application number: PCT/EP2021/053448
Authority: WO
Inventors: Poul Kim Madsen; Niels Nielsen Poulsen
Original assignee: Maersk Container Industry A/S
Priority date: 2020-02-12
Filing date: 2021-02-12
Publication date: 2021-08-19
Also published as: DK181078B1; DK202070082A1; EP4103839A1

Abstract

The disclosure relates to a flow guide (1) for a reciprocating-type compressor of a cooling system, the compressor comprising a pressure chamber (2), a suction chamber (3) formed by a valve plate (4) and a cylinder head (5), a cylinder chamber (6) placed on a side of the valve plate (4) opposite the cylinder head (5) wherein the flow guide (1) is formed directly in the cylinder head (5) by drilling, milling or molding of the cylinder head (5), providing the cylinder head (5) with one or more channels (7), guiding intake refrigerant from an inlet opening (8) of the cylinder head (5) to one or more suction openings (9) leading from the suction chamber (3) into the cylinder chamber (6). The disclosure further relates to a flow guide (1) for a reciprocating-type compressor of a cooling system, a reciprocating-type compressor for a cooling system, a reciprocating-type compressor for a cooling system, a use of a flow guide (1), a method of optimizing a reciprocating-type compressor of a cooling system and a method of optimizing a reciprocating-type compressor of a cooling system.

Description

A FLOW GUIDE FOR A RECIPROCATING-TYPE COMPRESSOR OF A COOLING SYSTEM AND A RECIPROCATING-TYPE COMPRESSOR FOR A COOLING SYSTEM COMPRISING SAID FLOW GUID

Technical field

The present disclosure relates to a flow guide for a reciprocating-type compressor of a cooling system, the compressor comprising a pressure chamber, a suction chamber formed by a valve plate and a cylinder head, a cylinder chamber placed on a side of the valve plate opposite the cylinder head.

The present disclosure also relates to a reciprocating-type compressor for a cooling system, the compressor comprising a pressure chamber, a suction chamber formed by a valve plate and a cylinder head, a cylinder chamber placed on a side of the valve plate opposite the cylinder head.

The present disclosure further relates to use of a flow guide in a reciprocating- type compressor for optimizing performance of the compressor.

Finally, the present disclosure finally relates to a method of optimizing a reciprocating-type compressor of a cooling system, the compressor comprising a pressure chamber, a suction chamber formed by a valve plate and a cylinder head, a cylinder chamber placed on a side of the valve plate opposite the cylinder head.

Background art

In general, compressors of a reciprocating-type used in cooling systems have a simple inflow arrangement, where intake refrigerant from an evaporator is led through an inlet opening of the compressor into a suction chamber and further through a suction opening in a valve plate into a cylinder chamber for compression of the refrigerant. The compressed refrigerant it then led back into the cooling circuit to the evaporator via a condenser. In some solutions, an economizer is placed in the cooling circuit between the condenser and the evaporator. The reciprocating compressor can be of a single stage type or a multiple stage type. US 2015/0361972 A1 discloses a refrigerant compressor system, comprising at least one low-pressure stage and at least one high-pressure stage, a suction duct leading from a suction connection for the refrigerant to the low-pressure stage, an intermediate-pressure duct leading from the low- pressure stage to the high-pressure stage, a high-pressure connection connected to the high-pressure stage, and a lubricant bath to which the intermediate pressure in the intermediate pressure duct is applied. Here the low-pressure stage and the high-pressure stage comprises a first cylinder bank to form the low-pressure stage and a second cylinder bank to form the high- pressure stage, thus allowing both the low-pressure stage and the high- pressure stage to be separated in a simple manner by the fact that they are formed by different cylinder banks of a compressor.

Such compressors normally discloses a suction chamber formed as a hollow cylinder head showing a relatively large empty space or volume within the cylinder head as illustrated in Figure 1.

A problem with the solutions of the prior art is that when operating the compressor, the refrigerant passing through the suction chamber and through one or more suction openings in the valve plate will swirl around in the suction chamber when entering a cylinder chamber through the one or more suction openings in the valve plate.

Further the suction openings in the valve plate are holes forming sharp edges, causing more flow resistance to the refrigerant when entering the cylinder chamber. There is thus a need for improved arrangements for optimizing of inflow performance of the compressor.

Summary It is an object of the present disclosure to mitigate, alleviate or eliminate one or more of the above-identified deficiencies and disadvantages in the prior art and solve at least the above mentioned problem.

According to a first aspect there is provided a flow guide for a reciprocating- type compressor of a cooling system, the compressor comprising a pressure chamber, a suction chamber formed by a valve plate and a cylinder head, a cylinder chamber placed on a side of the valve plate opposite the cylinder head, wherein the flow guide is formed directly in the cylinder head by drilling, milling or molding of the cylinder head, providing the cylinder head with one or more channels, guiding intake refrigerant from an inlet opening of the cylinder head to one or more suction openings leading from the suction chamber into the cylinder chamber.

The reciprocating compressor in the cooling system can be of a single stage type or a multiple stage type. For example in a two stage type compressor, a first stage compresses refrigerant from an evaporator in the cooling system to a first compression level and a second stage compresses the refrigerant to a second compression level, the first and second stages being fluidly connected by piping or channels in a housing of the compressor, which piping or channels are separated from pressure chamber and cylinder chamber of the first and second stage by valves.

Hereby is achieved, that the refrigerant flow is divided, introducing a minimum of turbulence.

According to a second aspect there is provided a flow guide for a reciprocating- type compressor of a cooling system, the compressor comprising a pressure chamber, a suction chamber formed by a valve plate and a cylinder head, a cylinder chamber placed on a side of the valve plate opposite the cylinder head, wherein the flow guide is formed in the cylinder head by an insert, which insert is provided with one or more channels, the insert guiding intake refrigerant from an inlet opening of the cylinder head to one or more suction openings leading from the suction chamber into the cylinder chamber.

Hereby is achieved that the flow guide easily can be changed without need to change the whole cylinder head. Also giving an opportunity to adapt the flow guide to different flow characteristics, for example for different refrigerants or mixtures of refrigerants.

According to some embodiments, each channel is formed internally in the insert.

Hereby it is possible to manufacture the insert by molding, injection molding or forging.

According to some embodiments, each channel is formed as a groove on an outer side of the insert.

Hereby it is possible to manufacture the insert by molding, injection molding or forging or to manufacture the insert by processing or machining a massive or solid block.

According to some embodiments, each channel at an end abutting the inlet opening has an opening diameter corresponding to a diameter of the inlet opening. Hereby is achieved a smooth flow through the inlet opening. According to some embodiments, each channel at an end abutting a suction opening has an opening diameter corresponding to a diameter of the suction opening. Hereby is achieved a smooth flow through the suction opening.

According to some embodiments, the number of channels is joined in a mutual inlet end and in the opposite end of the channels, abutting the one or more suction openings in the valve plate.

Hereby is achieved a smooth flow through a number of inlet channels, joined in an inlet and in the opposite end of the channels, abutting the suction opening of the valve plate. According to some embodiments, the flow guide at least partly comprises a material having a thermal conductivity being lower than a thermal conductivity of a material of which a cylinder and/or a cylinder head is made of.

According to some embodiments, the flow guide at least partly comprises a ceramic material and/or a plastic material and/or a composite material including carbon fibers.

Hereby is achieved a reduction of thermal shortcut, reducing heat exchange in the cylinder head.

According to a third aspect there is provided a reciprocating-type compressor for a cooling system, the compressor comprising a pressure chamber, a suction chamber formed by a valve plate and a cylinder head, a cylinder chamber placed on a side of the valve plate opposite the cylinder head, wherein a flow guide is formed directly in the cylinder head by drilling, milling or molding of the cylinder head, providing the cylinder head with one or more channels, guiding intake refrigerant from an inlet opening of the cylinder head to one or more suction openings leading from the suction chamber into the cylinder chamber.

Hereby is achieved, that flow through the cylinder head is enhanced and that performance of the compressor in the refrigerating circuit is improved.

According to a fourth aspect there is provided a reciprocating-type compressor for a cooling system, the compressor comprising a pressure chamber, a suction chamber formed by a valve plate and a cylinder head, a cylinder chamber placed on a side of the valve plate opposite the cylinder head, wherein a flow guide is formed in the cylinder head by an insert, which insert is provided with one or more channels, the insert guiding intake refrigerant from an inlet opening of the cylinder head to one or more suction openings leading from the suction chamber into the cylinder chamber.

Hereby is achieved that the compressor can be improved in that the flow guide easily can be changed without need to change the whole cylinder head. Also giving an opportunity to adapt the flow guide to different flow characteristics, for example for different refrigerants or mixtures of refrigerants.

According to some embodiments, each channel is formed internally in the insert.

According to some embodiments, each channel is formed as a groove on an outer side of the insert. Hereby it is possible to manufacture the insert by molding, injection molding or forging or to manufacture the insert by processing or machining a massive or solid block. According to some embodiments, each channel at an end abutting the inlet opening has an opening diameter corresponding to a diameter of the inlet opening. Hereby is achieved a smooth flow through the inlet opening.

According to some embodiments, each channel at an end abutting a suction opening has an opening diameter corresponding to a diameter of the suction opening.

Hereby is achieved a smooth flow through the suction opening.

Hereby is achieved a smooth flow through a number of inlet channels, joined in an inlet and in the opposite end of the channels, abutting the suction opening of the valve plate.

According to some embodiments, the flow guide at least partly comprises a material having a thermal conductivity being lower than a thermal conductivity of a material of which a cylinder and/or a cylinder head is made of. According to some embodiments, the flow guide at least partly comprises a ceramic material and/or a plastic material and/or a composite material including carbon fibers.

Hereby is achieved a reduction of thermal shortcut, reducing heat exchange in the cylinder head. According to a fifth aspect there is provided a use of a flow guide according to any of the embodiments of the first and second aspects in a reciprocating-type compressor for optimizing performance of the compressor. According to a sixth aspect there is provided a method of optimizing a reciprocating-type compressor of a cooling system, the compressor comprising a pressure chamber, a suction chamber formed by a valve plate and a cylinder head, a cylinder chamber placed on a side of the valve plate opposite the cylinder head, wherein the method comprises forming a flow guide in the cylinder head by drilling, milling or molding of the cylinder head, providing the cylinder head with one or more channels, guiding intake refrigerant from an inlet opening of the cylinder head to one or more suction openings leading from the suction chamber into the cylinder chamber. Hereby is achieved, a method of optimizing the flow through the cylinder head and improving the performance of the compressor in the refrigerating circuit.

According to a seventh aspect there is provided a method of optimizing a reciprocating-type compressor of a cooling system, the compressor comprising a pressure chamber, a suction chamber formed by a valve plate and a cylinder head, a cylinder chamber placed on a side of the valve plate opposite the cylinder head, wherein the method comprises placing a flow guide, formed by an insert, in the suction chamber, which insert is provided with one or more channels, guiding intake refrigerant from an inlet opening of the cylinder head to one or more suction openings leading from the suction chamber into the cylinder chamber.

Hereby is achieved, a method of optimizing the flow through the cylinder head and improving the performance of the compressor in the refrigerating circuit. According to some embodiments, the method comprises replacing the cylinder head with a cylinder head the method comprises one or more channels, guiding intake refrigerant from an inlet opening of the cylinder head to one or more suction openings leading from the suction chamber into the cylinder chamber.

Hereby is achieved a method of improving the performance of the compressor in the refrigerating circuit by replacing the original cylinder head with a cylinder head with optimized flow.

Effects and features of the second through seventh aspects are to a large extent analogous to those described above in connection with the first aspect. Embodiments mentioned in relation to the first aspect are largely compatible with the second through seventh aspects.

The present disclosure will become apparent from the detailed description given below. The detailed description and specific examples disclose preferred embodiments of the disclosure by way of illustration only. Those skilled in the art understand from guidance in the detailed description that changes and modifications may be made within the scope of the disclosure.

Hence, it is to be understood that the herein disclosed disclosure is not limited to the particular component parts of the device described or steps of the methods described since such device and method may vary. It is also to be understood that the terminology used herein is for purpose of describing particular embodiments only, and is not intended to be limiting. It should be noted that, as used in the specification and the appended claim, the articles "a", "an", "the", and "said" are intended to mean that there are one or more of the elements unless the context explicitly dictates otherwise. Thus, for example, reference to "a unit" or "the unit" may include several devices, and the like. Furthermore, the words "comprising", "including", "containing" and similar wordings does not exclude other elements or steps. Brief descriptions of the drawings

The above objects, as well as additional objects, features and advantages of the present disclosure, will be more fully appreciated by reference to the following illustrative and non-limiting detailed description of example embodiments of the present disclosure, when taken in conjunction with the accompanying drawings.

Figure 1 shows an example of a known cylinder head on top of a pair of cylinders (prior art);

Figure 2 shows a 1st stage cylinder head, according to an embodiment of the present disclosure with a part of the cylinder head cut away, showing a suction channel; Figure 3 shows an embodiment of a 1 st stage cylinder head, with another part of the cylinder head cut away, showing a different view of the suction channels;

Figure 4 shows a cross section of an embodiment of a 2^nd stage cylinder head on top of a pair of cylinders;

Figure 5 shows a cross section of a 2nd stage cylinder head seen from the valve plate side;

Figure 6 shows a 2^nd stage cylinder head with an insert seen from the valve plate side;

Figure 7 shows the insert, and

Figure 8 shows the cylinder head of figure 6 without the insert. Detailed description

The present disclosure will now be described with reference to the accompanying drawings, in which preferred example embodiments of the disclosure are shown. The disclosure may, however, be embodied in other forms and should not be construed as limited to the herein disclosed embodiments. The disclosed embodiments are provided to fully convey the scope of the disclosure to the skilled person.

A cross section of a cylinder bank 13 where a prior art cylinder head 5 is placed on top of a pair of cylinder chambers 6 is shown in Figure 1.

The cylinder head 5 is mounted to a cylinder body by screws or bolts through mounting holes 10 in the cylinder head 5. The cylinder banks 13 comprises one or more cylinders having a cylinder space or chamber 6 in which a piston can be moved to compress a refrigerant media, a cylinder head 5 and a valve plate 4. The cylinder head 5 forms a suction chamber 3 and a pressure chamber 2 (not shown in figure 1). The suction chamber 3 and the pressure chamber 2 is separated from each other by a separating wall in the cylinder head 5 and from the cylinder chamber 6 by the valve plate 4. The valve plate 4 is provided with a one way valve (not shown), which valve can be in a simple form, where valves are formed by resilient thin plate-shaped elements called valve tongues. Valve seats are formed by a plane valve plate 4 with inlet and/or outlet holes 9. The valve tongue is fastened in one end and can in its free end bend in relation to the valve plate 4. The valve tongue is placed on a pressure side of the valve plate 4. When a piston (not shown) moves in the cylinder chamber 6 in an intake stroke, the valve tongue will bend slightly and let in refrigerant through the suction opening 9 into the cylinder chamber 6. When the piston has moved into a bottom position and changes to move into an upward direction and into a compression stroke, the valve tongue will return to its unloaded position and will be pressed against the valve plate 4, closing the suction opening 9. In case the valve plate 4 is provided with more than one suction opening 9, a corresponding number of tongue valves are used. In an embodiment one or more tongue valves is configured to cover more than one suction opening 9. In the pressure chamber 2, a similar valve arrangement can be placed. Here the tongue valve or valves are located on a side of the valve plate 4 opposite to the cylinder chamber 6. When the piston starts a compression stroke, the valve will open for exhausting refrigerant as long as the pressure in the cylinder chamber 6 is higher than the pressure in the pressure chamber 2 of the cylinder head 5.

When the pressure in the cylinder chamber 6 is lower than the pressure in the pressure chamber 2, the tongue valve will be pressed against the valve plate

4, closing the exhaust opening.

In prior art the suction chamber 3 is formed as a hollow cylinder head 5 showing a relatively large empty space or volume within the cylinder head 5.

Generally, the purpose with the flow guide is to divide the flow with a minimum of changes of direction, and if possible having largest possible bending radiuses.

The first aspect of this disclosure shows a flow guide 1 for a reciprocating-type compressor of a cooling system, the compressor comprising a pressure chamber 2 , a suction chamber 3 formed by a valve plate 4 and a cylinder head

5, a cylinder chamber 6 placed on a side of the valve plate 4 opposite the cylinder head 5 wherein the flow guide 1 is formed directly in the cylinder head 5 by drilling, milling or molding of the cylinder head 5, providing the cylinder head 5 with one or more suction channels 7, guiding intake refrigerant from an inlet opening 8 of the cylinder head 5 to one or more suction openings 9 leading from the suction chamber 3 into the cylinder chamber 6. Here the suction chamber 3 is formed by the one or more channels 7.

The second aspect of this disclosure shows a flow guide 1 for a reciprocating- type compressor of a cooling system, the compressor comprising a pressure chamber 2 , a suction chamber 3 formed by a valve plate 4 and a cylinder head

5, a cylinder chamber 6 placed on a side of the valve plate 4 opposite the cylinder head 5, wherein the flow guide 1 is formed in the cylinder head 5 by an insert 11 , which insert 11 is provided with one or more channels 7, the insert 11 guiding intake refrigerant from an inlet opening 8 of the cylinder head 5 to one or more suction openings 9 leading from the suction chamber 3 into the cylinder chamber 6.

Here the suction chamber 3 is formed by channels 7 in the insert 11. The insert 11 is placed in a groove or space 12 formed in the cylinder head 5.

Figures 5 to 8 shows the cylinder head 5 with the insert 11 and the cylinder head 5 with the insert 11 removed, showing the space 12 for the insert 11 , as well as the insert 11 alone.

The cylinder head 5 is mounted to the compressor (not shown) by screws or bolts, through mounting holes 10 in the cylinder head 5.

When mounting the cylinder head 5 to the compressor, a gasket 14 or another kind of sealing means can be placed between the cylinder head 5 and the valve plate 4. A gasket can also be placed between the cylinders and the valve plate 4.

Forming the suction chamber 3 by channels 7, the volume and cross section of the suction chamber 3 is reduced and flow through the suction chamber 3 is optimized. In one embodiment, each channel 7 is formed internally in the insert 11.

In another embodiment, each channel 7 is formed as a groove on an outer side of the insert 11.

This is a convenient way to reduce internal volume in the suction chamber 3 or suction channel 7 and to provide a guided flow for the refrigerant on its way through the cylinder head 5 and into the cylinder chamber 6 through the suction opening 9.

Providing the flow guide 1 as an insert 11, makes it possible to manufacture different configurations of the suction channels 7 in a cheap and easy way.

In an embodiment, the cylinder head 5 is configured in such a way that each channel 7, at an end abutting the inlet opening 8, has an opening diameter corresponding to a diameter of the inlet opening 8.

In an embodiment, the cylinder head 5 is configured in such a way that each channel 7 at an end abutting a suction opening 9 has an opening diameter corresponding to a diameter of the suction opening 9.

Hereby the refrigerant flow is strained and guided, with a minimum of changes of fluid velocity (caused by changes in section area) leading to small changes in static pressure combined with a smooth geometry reducing flow related pressure drops.

In an embodiment, the cylinder head 5 is configured in such a way that the number of channels 7 is joined with or in a mutual intake end or inlet opening 8 and at the opposite end of the channels 7, abutting the one or more suction openings 9 in the valve plate 4. Here the joining channels 7 can meet in a mutual spot, forming an intake or inlet 8 common for the channels 7 or the channels can all be connected to a space forming part of the suction chamber fluidly connected to the one or more suction openings 9 in the valve plate 4 through the channels 7.

In an embodiment, the flow guide 1 at least partly comprises a material having a thermal conductivity being lower than a thermal conductivity of a material of which a cylinder 13 and/or a cylinder head 5 is made of.

In an embodiment, the flow guide 1 at least partly comprises a ceramic material and/or a plastic material and/or a composite material including carbon fibers.

The third aspect of this disclosure shows a reciprocating-type compressor for a cooling system, the compressor comprising a pressure chamber 2 , a suction chamber 3 formed by a valve plate 4 and a cylinder head 5, a cylinder chamber 6 placed on a side of the valve plate 4 opposite the cylinder head 5, wherein a flow guide 1 is formed directly in the cylinder head 5 by drilling, milling or molding of the cylinder head 5, providing the cylinder head 5 with one or more channels 7, guiding intake refrigerant from an inlet opening 8 of the cylinder head 5 to one or more suction openings 9 leading from the suction chamber 3 into the cylinder chamber 6.

The fourth aspect of this disclosure shows a reciprocating-type compressor for a cooling system, the compressor comprising a pressure chamber 2, a suction chamber 3 formed by a valve plate 4 and a cylinder head 5, a cylinder chamber 6 placed on a side of the valve plate 4 opposite the cylinder head 5, wherein a flow guide 1 is formed in the cylinder head 5 by an insert 11 , which insert 11 is provided with one or more channels 7, the insert 11 guiding intake refrigerant from an inlet opening 8 of the cylinder head 5 to one or more suction openings 9 leading from the suction chamber 3 into the cylinder chamber 6. In an embodiment, each channel 7 is formed internally in the insert 11. In an embodiment, each channel 7 is formed as a groove on an outer side of the insert 11.

In an embodiment, each channel 7 at an end abutting the inlet opening 8 has an opening diameter corresponding to a diameter of the inlet opening 8.

In an embodiment, each channel 7 at an end abutting a suction opening 9 has an opening diameter corresponding to a diameter of the suction opening 9. In an embodiment, the number of channels 7 is joined in a mutual inlet end 8 and in the opposite end of the channels 7, abutting the one or more suction openings 9 in the valve plate 4.

The fifth aspect of this disclosure shows use of a flow guide according to any of its embodiments in a reciprocating-type compressor for optimizing performance of the compressor. The sixth aspect of this disclosure shows a method of optimizing a reciprocating-type compressor of a cooling system, the compressor comprising a pressure chamber 2, a suction chamber 3 formed by a valve plate 4 and a cylinder head 5, a cylinder chamber 6 placed on a side of the valve plate 4 opposite the cylinder head 5, wherein the method comprises forming a flow guide 1 in the cylinder head 5 by drilling, milling or molding of the cylinder head 5, providing the cylinder head 5 with one or more channels 7, guiding intake refrigerant from an inlet opening 8 of the cylinder head 5 to one or more suction openings 9 leading from the suction chamber 3 into the cylinder chamber 6.

The seventh aspect of this disclosure shows a method of optimizing a reciprocating-type compressor of a cooling system, the compressor comprising a valve plate 4, a cylinder head 5, a pressure chamber 2 and a suction chamber 3 formed by the valve plate 4 and the cylinder head 5, and a cylinder chamber 6 placed on a side of the valve plate 4, opposite the cylinder head 5, wherein the method comprises placing a flow guide 1 , formed by an insert 11, in the suction chamber 3, which insert 11 is provided with one or more channels 7, guiding intake refrigerant from an inlet opening 8 of the cylinder head 5 to one or more suction openings 9 leading from the suction chamber 3 into the cylinder chamber 6. In an embodiment, the method comprises replacing the cylinder head 5 with a cylinder head 5 the method comprises one or more channels 7, guiding intake refrigerant from an inlet opening 8 of the cylinder head 5 to one or more suction openings 9 leading from the suction chamber 3 into the cylinder chamber 6. The person skilled in the art realizes that the present disclosure is not limited to the preferred embodiments described above. The person skilled in the art further realizes that modifications and variations are possible within the scope of the appended claims. Additionally, variations to the disclosed embodiments can be understood and effected by the skilled person in practicing the claimed disclosure, from a study of the drawings, the disclosure, and the appended claims.

Claims

1. A flow guide (1) for a reciprocating-type compressor of a cooling system, the compressor comprising a pressure chamber (2), a suction chamber (3) formed by a valve plate (4) and a cylinder head (5), a cylinder chamber (6) placed on a side of the valve plate (4) opposite the cylinder head (5), wherein the flow guide (1 ) is formed directly in the cylinder head (5) by drilling, milling or molding of the cylinder head (5), providing the cylinder head (5) with one or more channels (7), guiding intake refrigerant from an inlet opening (8) of the cylinder head (5) to one or more suction openings (9) leading from the suction chamber (3) into the cylinder chamber (6).

2. A flow guide (1) for a reciprocating-type compressor of a cooling system, the compressor comprising a pressure chamber (2), a suction chamber (3) formed by a valve plate (4) and a cylinder head (5), a cylinder chamber (6) placed on a side of the valve plate (4) opposite the cylinder head (5), wherein the flow guide (1) is formed in the cylinder head (5) by an insert (11), which insert (11) is provided with one or more channels (7), the insert (11) guiding intake refrigerant from an inlet opening (8) of the cylinder head (5) to one or more suction openings (9) leading from the suction chamber (3) into the cylinder chamber (6).

3. The flow guide (1 ) according to claim 2, wherein each channel (7) is formed internally in the insert (11 ).

4. The flow guide (1) according to claim 2, wherein each channel (7) is formed as a groove on an outer side of the insert (11 ).

5. The flow guide (1) according to any of claims 1 - 4, wherein each suction channel (7) at an end abutting the inlet opening (8) has an opening diameter corresponding to a diameter of the inlet opening (8).

6. The flow guide (1) according to any of claims 1 - 5, wherein each suction channel (7) at an end abutting a suction opening (9) has an opening diameter corresponding to a diameter of the suction opening (9).

7. The flow guide (1 ) according to any of the claims 1 - 6, wherein the number of suction channels (7) is joined in a mutual inlet end (8) and in the opposite end of the channels (7), abutting the one or more suction openings (9) in the valve plate (4).

8. The flow guide (1 ) according to any of claims 1 - 7, wherein the flow guide

(1) at least partly comprises a material having a thermal conductivity being lower than a thermal conductivity of a material of which a cylinder (13) and/or a cylinder head (5) is made of.

9. The flow guide (1 ) according to any of claims 1 - 7, wherein the flow guide

(1 ) at least partly comprises a ceramic material and/or a plastic material and/or a composite material including carbon fibers.

10. A reciprocating-type compressor for a cooling system, the compressor comprising a pressure chamber (2), a suction chamber (3) formed by a valve plate (4) and a cylinder head (5), a cylinder chamber (6) placed on a side of the valve plate (4) opposite the cylinder head (5), wherein a flow guide (1) is formed directly in the cylinder head (5) by drilling, milling or molding of the cylinder head (5), providing the cylinder head (5) with one or more channels (7), guiding intake refrigerant from an inlet opening (8) of the cylinder head (5) to one or more suction openings (9) leading from the suction chamber (3) into the cylinder chamber (6).