DE102016105144B4 - Dry running piston compressor with crank mechanism cooling - Google Patents

Abstract

There has been proposed a dry-running reciprocating compressor having at least one cylinder for compressing air by means of a piston movably disposed therein. The compressor further comprises a crankcase, in which a crankshaft is rotatably mounted, on which at least one connecting rod connected to a piston is rotatably mounted. The intake air of the at least one cylinder is guided through the crankcase for cooling the crank drive. The piston compressor further comprises a cooling device, by means of which the at least one cylinder supplied intake air is cooled after flowing through the crankcase.

Description

The invention relates to a dry running piston compressor with at least one cylinder for compressing air by means of a piston movably arranged therein and with a crankcase, in which a crankshaft is rotatably mounted, on which at least one connecting rod connected to a piston is rotatably mounted, wherein the intake air of at least one cylinder for cooling the crank mechanism is guided by the crankcase.

For modern dry-running and thus in particular oil-free air-cooled piston compressors, a high power density and efficiency is sought. In order to avoid overheating of the crank mechanism, which is usually arranged in a crankcase, to provide sufficient cooling. However, such compressors have no cooling oil or other cooling medium available for this purpose.

A dry running piston compressor, for example, from the German patent application DE 41 10 912 A1 known, in which the cool intake air flows through the crankcase coming from the intake system on the way to the first stage of the compressor and thereby cools the crank mechanism, the same sogo for a good mixing of the air in the crankcase. The cooling air is the output air, which is subsequently fed into the cylinder for compression. Thus, the volume flow of the cooling air corresponds to the delivery performance of the compressor. A disadvantage of this compressor is that although a reduction in the crankcase temperature can be achieved, but the temperature of the intake air as it flows through the crankcase and thus increased before entering the cylinder, whereby the delivery performance of the compressor decreases.

Furthermore, from the published patent application US 5 957 667 A a dry running compressor known in piston construction, in which the intake air also flows through the crankcase of the reciprocating compressor and is previously passed through the same for cooling the drive motor. In addition, a cooling device in the form of a blower is disclosed here, which is placed outside the compressor or crankcase and which allows air to flow along the suction line of the piston compressor and the surface of the compressor or crankcase for cooling. Again, it must be assumed that the supply of air through the heating of the intake air in the crankcase, whereby the heating is reduced by the cooling of the fan again.

The invention is therefore based on the object to provide an improved dry-running piston compressor with sufficient cooling of the crank mechanism, which allows high efficiency and power density.

To solve this problem, a dry-running piston compressor is proposed according to claim 1. Further developments of the reciprocating compressor are the subject of the dependent claims.

To achieve the object, a dry-running piston compressor is proposed which has at least one cylinder for compressing air by means of a piston arranged movably therein. The compressor further comprises a crankcase, in which a crankshaft is rotatably mounted, on which at least one connecting rod connected to a piston is rotatably mounted. The intake air of the at least one cylinder is guided through the crankcase for cooling the crank drive. The piston compressor according to the invention further comprises a cooling device, by means of which the at least one cylinder supplied intake air after the flow through the crankcase is cooled.

The inventive dry-running piston compressor has at least one cylinder for compressing air by means of a piston arranged movably therein. According to the invention, the reciprocating compressor may also comprise two or more cylinders arranged in succession or in parallel, which are provided for compressing air by means of a respective piston arranged movably therein. A piston compressor according to the invention can consequently be designed in one or more stages.

The reciprocating compressor is driven by a crankshaft, which is rotatably mounted in a crankcase. Each connecting rod connected to a piston are rotatably supported at an eccentric position of the crankshaft so that its rotational movement is transmitted as a lifting movement to the piston which moves axially in a cylinder.

The intake air of the at least one cylinder is guided through the crankcase for cooling the crank drive. The intake air is essentially the air which is later sucked into the at least one cylinder of the reciprocating compressor and compressed there, that is to say compressed. The air guided through the crankcase flows over the elements of the crank mechanism, absorbs heat energy and heats up at the same time. As a crank mechanism here are meant to drive the reciprocating compressor parts, so that at least the crankshaft, connected to this to drive the piston connecting rod and arranged at this and between these bearings.

The piston compressor according to the invention further comprises a cooling device, by means of which the at least one cylinder supplied intake air is cooled after flowing through the crankcase. As the intake air heats up as it flows through the crankcase, its density is reduced, so that the volume of the intake air quantity that can be absorbed into the cylinder in one operating stroke decreases in terms of temperature. As a result of the cooling of the intake air by the cooling device, the intake air quantity which can be absorbed in the cylinder in one working stroke increases. The power density and the efficiency of the reciprocating compressor thus increase by cooling the intake air by means of a cooling device, whereby a larger amount of intake air can be supplied to the at least one cylinder per power stroke.

As a cooling device for cooling the intake air of the dry-running piston compressor, the known embodiments of air cooling means, which are provided for transmitting heat energy of an air stream to another medium such as ambient air or a liquid cooling medium.

In the dry-running piston compressor, the intake air of the at least one cylinder for cooling the crank mechanism by means of a blower through the crankcase feasible. By a fan, the guided through the crankcase air flow can be increased. The fact that the volume flow in this solution is not exclusively due to the intake of air through the cylinder, for example, a favorable for the cooling of the crank mechanism or parts thereof air flow through the crankcase can be selected. Furthermore, the use of a blower makes it possible to increase the volume flow of the air, since more air can be passed into and through the crankcase for cooling. In addition, the use of a blower with the volume flow also increases the pressure of the intake air in front of the cylinder. As a result, the amount of intake air that can be received in the cylinder in one working cycle increases, in particular in conjunction with cooling of the intake air by the cooling device before the intake air is taken into the cylinder. In addition to the reduced intake temperature of the reciprocating compressor according to the invention, the power density and thus also the delivery performance of the compressor are further increased by the increased intake pressure with the aid of the fan, with simultaneously improved cooling of the crank drive.

In one embodiment of the dry-running piston compressor, the fan is designed as a rotationally fixed to the crankshaft connected fan. This solution requires no additional drive a fan, since this is connected as connected to the crankshaft fan directly from the crankshaft. As soon as the crankshaft drives the piston compressor, air is supplied to the crankcase by the action of the fan to cool the crank mechanism and, depending on its design and arrangement, also through the entire crankcase. The volume flow guided by the fan through the crankcase and its cooling effect are determined by the arrangement of the fan (in the region of an air inlet opening or an air outlet opening, in the air flow before or after the crank drive, etc.), by the design of the fan (outer diameter, number of wings, blade geometry, etc.). ) and the guidance of the air flow in the crankcase (louver (s), inlet opening (s), outlet opening (s), etc.) adaptable.

In one embodiment of the dry running piston compressor, the fan is designed as a radial fan, which may be rotatably connected to the crankshaft, or may be driven in another suitable manner. The choice of fan geometry is dependent on the desired guidance of the air through the crankcase.

In another embodiment of the dry-running reciprocating compressor, the fan is disposed outside of the crankcase and is also driven by a drive source outside the crankcase. The drive source used in this embodiment, for example, a specially provided for this purpose engine, or a transmission of torque from another available in the range of the piston compressor drive, for example by means of a belt, chain or wheel drive. Characterized in that the drive of such an external blower is operated independently of the speed of the reciprocating compressor, a largely arbitrary fan action and thus a largely arbitrary air flow can be provided. As a result, sufficient cooling of the crank mechanism can be ensured and the intake pressure in front of the at least one cylinder can be significantly increased, as a result of which the efficiency and power density of the piston compressor can be further increased.

In one embodiment of the dry running reciprocating compressor, the cooling means is formed by the conduit which guides the intake air from the crankcase to the at least one cylinder. The line has suitable means for heat dissipation to the environment. For example, the line may be formed significantly longer than is required to guide the air from the crankcase to the at least one cylinder. Thus, the line has a large outer surface over which a heat exchange with the environment is possible. Furthermore, the conduit can be suitable heat removal devices such Having ribs or other projections which increase the heat dissipating outer surface of the conduit. Also, the line may be at least partially made of a particularly good heat conducting material that allows cooling of the line flowing through the air, heated in the crankcase. The line between the crankcase and the at least one cylinder may also have any other suitable for heat dissipation design.

An embodiment of the dry-running reciprocating compressor has a hot air discharge device for discharging at least a portion of the air guided and thereby heated by the blower through the crankcase to the environment. This embodiment makes it possible to guide more air through the crankcase than can later be added as intake air in the at least one cylinder of the reciprocating compressor and compressed there. So can be maintained in the crankcase by the use of a Warmluftabführeinrichtung sufficient cooling air flow. By this design, the cooling of the crank mechanism can be improved and also the heating of the guided through the crankcase airflow can be reduced. By arranging the Warmluftabführeinrichtung before the cooling device, the excess cooling air can be dissipated in the heated state to the environment without cooling energy is required for their cooling.

The hot air discharge device can be designed, for example, in the form of a check valve or overpressure valve, which opens from a predetermined air pressure in the line between the crankcase and the cooling device. However, the hot air discharge device can also be designed so that it can be opened and closed depending on other parameter values, in particular by a control device. In another hot air discharge device, a predetermined proportion of the volume flow is removed from the crankcase in each case.

By using a Warmluftabführeinrichtung a largely arbitrarily large cooling air volume flow can be realized without a larger dimensioning of the cooling device is required.

An embodiment of the dry running reciprocating compressor includes a cold air diverter for diverting at least a portion of the intake air cooled by the radiator into the crankcase. This embodiment, in conjunction with the use of a blower, in addition to or as an alternative to the use of a Warmluftabführeinrichtung, to lead a larger volume flow through the crankcase, as later as intake air in the at least one cylinder of the reciprocating compressor and can be compressed there. Thus, the Kaltluftumleiteinrichtung also allows each sufficient cooling air flow in the crankcase. Thus, by means of a Kaltluftumleiteinrichtung the cooling air flow rate increased and the heating of the guided through the crankcase air can be reduced. Thus, the cooling of the crank mechanism is improved, wherein cooling energy is required for the cooling of the bypassed before the at least one cylinder intake air. In an embodiment in which the intake air is cooled to a lower temperature than the ambient temperature, the use of a Kaltluftumleiteinrichtung the cooling of the crank mechanism can be further improved.

The Kaltluftumleiteinrichtung can be formed, for example in the form of a check valve or pressure relief valve, which opens from a predetermined air pressure in the line between the cooling device and the at least one cylinder of the reciprocating compressor. However, the cold air diverter can also be designed so that it can be opened and closed depending on other parameter values, in particular by a control device. In another Kaltluftumleiteinrichtung each a predetermined proportion of the cooled volume flow of the intake air is fed back into the crankcase.

By means of a Warmluftabführeinrichtung a largely arbitrarily large cooling air volume flow can be realized, but a larger dimensions of the cooling device may be required.

In one embodiment of the dry-running piston compressor, the piston compressor has at least one second cylinder, to which the air compressed in the first cylinder can be supplied. In a second cylinder, which is already supplied with compressed air, this air is compressed even more. While a reciprocating compressor, which compresses the air only once, is referred to as "one-stage", a reciprocating compressor in which the air is recompressed in a second cylinder ("second stage") is referred to as a "two-stage" compressor. Compressors with further compression stages are referred to as "three-stage", "four-stage", etc. or "multi-stage" according to the successively arranged number of stages. In order to allow a greater compression of the air, cooling devices can be provided between the individual cylinders ("stages") of the compressor, which lower the temperature increase of the air resulting from the compression again. Likewise, two or more cylinders may be arranged in parallel, each representing a first stage of a multi-stage compressor.

An embodiment of the dry running reciprocating compressor includes a post-cooler for cooling the compressed air after passing through the at least one cylinder of the reciprocating compressor. By compressing the air in the cylinder heats up, so that the compressed air has an elevated temperature. Cooling of the compressed air by means of a post-cooling device arranged after passing through the at least one cylinder simplifies, for example, subsequent storage of the air or further processing, such as, for example, dehumidification of the air. In one embodiment of the reciprocating compressor, the post-cooler is formed by a partition of the cooler.

Further advantages, features and applications of the present invention will become apparent from the following description taken in conjunction with the figures.

1 shows a schematic representation of a first embodiment of an exemplary dry running reciprocating compressor according to the invention;

2 shows a schematic representation of a second embodiment of an exemplary dry running reciprocating compressor according to the invention;

3 shows a schematic representation of a third embodiment of an exemplary dry running reciprocating compressor according to the invention;

4 shows a schematic representation of a fourth embodiment of an exemplary dry running reciprocating compressor according to the invention; and

5 shows a schematic representation of a fifth embodiment of an exemplary dry-running piston compressor according to the invention.

1 shows a schematic representation of a first embodiment of an exemplary dry-running piston compressor according to the invention 10 with a crankcase 20 and one in the crankcase 20 arranged crankshaft 21 , which with a drive motor 22 connected and driven by this. The single-stage piston compressor shown in the embodiment 10 also has a cylinder 11 for compressing air by means of a piston arranged therein 12 on which one on the crankshaft 21 rotatably mounted connecting rod 13 is driven.

The crankshaft 21 forms with the connecting rod 13 and the bearings arranged on these and between these bearings the crank mechanism 15 which is in operation of the reciprocating compressor 10 inside the crankcase 20 heated and therefore requires sufficient cooling.

The crankcase 20 is also via an air supply line 25 with an air filter 26 connected, sucked over which cool ambient air and the air supply line 25 in the crankcase 20 to be led. For sucking the ambient air into the crankcase 20 and for forming an airflow through the crankcase 20 is on the crankshaft 21 a wave-proof fan in the form of a fan 27 arranged, which can also be designed as a radial fan. The air flow formed by this fan flows over the elements of the crank mechanism 15 while taking on simultaneous cooling of the crank mechanism 15 Heat energy up.

Using the fan 27 will be in the crankcase 20 heated air in a the crankcase 20 with the cylinder 11 connecting line 31 guided, which the cylinder 11 feeds the intake air. In or on the line 31 is a cooling device 32 arranged, by means of which the intake air is cooled, before this by the lifting movement of the piston 12 in the cylinder 11 is sucked. After compressing the air in the cylinder 11 this is through a discharge line 34 guided in a memory device, not shown. In or on the discharge line 34 is a post-cooling device 35 arranged in which the compressed air after heating during compression in the cylinder 11 of the reciprocating compressor 10 is cooled again.

At this in 1 shown exemplary embodiment, the cooling air volume flow of the increased delivery performance of the reciprocating compressor 10 , The delivery performance increases due to the additional cooling in the cylinder 11 injectable intake air, further due to the fan 27 additionally the crankcase 20 flows through and under increased pressure in the pipe 31 pending.

2 shows a schematic representation of a second embodiment of an exemplary dry-running piston compressor according to the invention 10 , The piston compressor 10 out 2 is largely the same as in 1 shown and described for this purpose piston compressor 10 , so that same elements of the reciprocating compressors 10 be denoted by the same reference numerals. The following are just the differences between the two reciprocating compressors 10 explained.

The in 2 shown piston compressor 10 points opposite to the piston compressor 1 a cold air diverter 36 in the form of a pressure relief valve. In the embodiment shown, the pressure relief valve of the cold air guide opens 36 as soon as the pressure in the pipe 31 after the cooling device 32 exceeds a predetermined value. The cold air diverter 36 then directs a portion of the after flowing through the crankcase 20 through the cooling device 32 cooled intake air with newly sucked in ambient air from the air filter 26 back to the crankcase 20 , In this way, the volume flow of air through the crankcase 20 to its cooling be greater than the delivery of the reciprocating compressor 10 because the air after flowing through the crankcase 20 and after cooling back into the crankcase 20 is guided to the crank mechanism 15 continue to cool. At the same time, less new air from the environment through the air filter 26 sucked.

In this exemplary embodiment, an arbitrarily large flow of cooling air can be realized, wherein the cooling device 20 opposite the piston compressor 10 out 1 adapted for the increased volume flow. When compared with the piston compressor off 1 the same delivery performance is also the amount of through the air filter 26 sucked air quantity equal.

3 shows a schematic representation of a third embodiment of an exemplary dry-running piston compressor according to the invention 10 , The piston compressor 10 out 3 is largely the same as in 1 shown and described for this purpose piston compressor 10 , so that same elements of the reciprocating compressors 10 be denoted by the same reference numerals. The following are just the differences between the two reciprocating compressors 10 explained.

The in 3 shown piston compressor 10 points opposite to the piston compressor 1 a hot air discharge device 37 in the form of a pressure relief valve. The hot air discharge device 37 is in the lead 31 even before the cooling device 32 arranged and performs at least part of the fan 27 through the crankcase 20 guided air to the environment. In the embodiment shown, the pressure relief valve of the hot air discharge opens 37 as soon as the pressure in the pipe 31 after exiting the crankcase 32 rises above a predetermined value. This allows a desired flow in the crankcase 20 be maintained. The hot air discharge device 37 then directs a portion of the heated air to the crankcase 20 flows through it while the crank mechanism 15 Chilled, to the environment. Also in this way, the volume flow of air through the crankcase 20 for cooling the crank mechanism 15 be greater than the delivery of the reciprocating compressor 10 because the air after flowing through the crankcase 20 partially dissipated to the environment.

In this exemplary embodiment, an arbitrarily large flow of cooling air can be realized, wherein the cooling device 32 this is unaffected. When compared with the piston compressor off 1 same delivery performance, however, increases the amount of the air filter 26 sucked air, which is why the air filter 26 opposite the air filter 26 out 1 may be interpreted as correspondingly larger.

4 shows a schematic representation of a fourth embodiment of an exemplary dry-running piston compressor according to the invention 10 , The piston compressor 10 out 4 is largely the same as in 1 shown and described for this purpose piston compressor 10 , so that same elements of the reciprocating compressors 10 be denoted by the same reference numerals. The following are just the differences between the two reciprocating compressors 10 explained.

At the in 4 shown piston compressor 10 becomes the cooling device 32 from the line 31 formed, which the intake air from the crankcase 20 to the cylinder 11 leads. The administration 31 has one opposite the line 31 of the reciprocating compressor 10 out 1 significantly increased length. This additional line length represents a suitable means for heat dissipation through the enlarged outer surface, via which heat energy is released to the environment 4 schematically illustrated embodiment of the reciprocating compressor 10 So it is a simplified and inexpensive design compared to the reciprocating compressor 10 out 1 , The in 4 illustrated piston compressor 10 indicates due to the opposite to the reciprocating compressor 10 out 1 lower cooling capacity of the additional line length of the line 31 realized cooling device 32 a slightly lower efficiency.

5 shows a schematic representation of a fifth embodiment of an exemplary dry-running piston compressor according to the invention 10 , The piston compressor 10 out 5 is largely the same as in 1 shown and described for this purpose piston compressor 10 , so that same elements of the reciprocating compressors 10 be denoted by the same reference numerals. The following are just the differences between the two reciprocating compressors 10 explained.

The in 5 shown piston compressor 10 points opposite the piston compressor 10 out 1 no fan in the form of a shaft-fixed fan 27 on, but outside the crankcase 20 arranged fan 28 that from an external fan drive 29 is driven. The fan 28 is within the crankcase 20 with the cylinder 11 connecting line 31 arranged. By the effect of the blower 28 Ambient air is passed through the air filter 26 in the crankcase 20 sucked where it is above the elements of the crank mechanism 15 flows and thereby extracts heat energy. Furthermore, the fan sucks 28 the heated air after flowing through the crankcase 20 into the pipe 31 and leads these on to the cooling device 32 and by the one in the line 31 built up pressure finally to the cylinder 11 ,

Unlike one through the crankshaft 21 powered blowers, like the one in the 1 to 4 shown fan 27 , can be an externally powered blower 28 be operated at any fan speed, whereby the flow through the crankcase 20 and the intake pressure in front of the cylinder 11 can be further increased. So can the power density of the reciprocating compressor 10 be further increased.

In the 2 to 5 are different embodiments of the reciprocating compressor 10 shown, which each have a modified or additional component relative to the embodiment of the reciprocating compressor 10 out 1 exhibit. Of course, there are also embodiments of the reciprocating compressor 10 possible, which compared to the embodiment of 1 have two or more of the modifications shown in the other exemplary embodiments and described herein.

Thus, for example, in a modification of the in 5 illustrated embodiment of the reciprocating compressor 10 with a hot air discharge device 37 even then a cooling air flow are generated when the crankshaft 21 not driven.

The features of the invention disclosed in the foregoing description, in the drawings and in the claims may be essential to the realization of the invention both individually and in any combination.

LIST OF REFERENCE NUMBERS

10

piston compressor

11

cylinder

12

piston

13

pleuel

15

crankshaft

20

crankcase

21

crankshaft

22

drive motor

25

Air supply line

26

air filter

27

Fan

28

fan

29

fan drive

31

management

32

cooling device

34

discharge line

35

after-cooling

36

Kaltluftumleiteinrichtung

37

Warmluftabführeinrichtung

Claims (9)

Dry-running piston compressor with at least one cylinder ( 11 ) for compressing air by means of a piston arranged movably therein ( 12 ) and with a crankcase ( 20 ), in which a crankshaft ( 21 ) is rotatably mounted on which at least one with a piston ( 12 ) connected connecting rod ( 13 ) is rotatably mounted, wherein the intake air of the at least one cylinder ( 11 ) for cooling the crank mechanism ( 15 ) through the crankcase ( 20 ), wherein the reciprocating compressor ( 10 ) a cooling device ( 32 ), by means of which the at least one cylinder ( 11 ) supplied intake air after flowing through the crankcase ( 20 ) is cooled, characterized in that the intake air of the at least one cylinder ( 11 ) for cooling the crank mechanism ( 15 ) using a blower ( 27 . 28 ) through the crankcase ( 20 ) is feasible. Dry-running piston compressor according to claim 1, characterized in that the fan rotatably with the crankshaft ( 21 ) connected fan ( 27 ) is trained. Dry-running piston compressor according to claim 1 or 2, characterized in that the fan as a radial fan ( 27 ) is trained. Dry-running piston compressor according to claim 1, characterized in that the blower ( 28 ) outside the crankcase ( 20 ) is arranged. Dry-running piston compressor according to one of the preceding claims, characterized in that the cooling device ( 32 ) through the line ( 31 ) is formed, which the intake air from the crankcase ( 20 ) to at least one cylinder ( 11 ), whereby the line ( 31 ) has suitable means for heat dissipation to the environment. Dry-running piston compressor according to one of claims 1 to 5, characterized by a hot air discharge device ( 37 ), for discharging at least a part of the blower ( 27 . 28 ) through the crankcase ( 20 ) guided air to the environment. Dry running piston compressor according to one of claims 1 to 6, characterized by a cold air diverter ( 36 ) for diverting at least a portion of the heat exchangers ( 32 ) cooled intake air into the crankcase ( 20 ). Dry-running piston compressor according to one of the preceding claims, characterized by at least one second cylinder to which the one in the first cylinder ( 11 ) compressed air can be supplied. Dry-running piston compressor according to one of the preceding claims, characterized by a post-cooling device ( 35 ) for cooling the compressed air after passing through the at least one cylinder ( 11 ) of the reciprocating compressor ( 10 ).

Images