DE102016201208A1 - Piston compressor with ventilation device - Google Patents

Abstract

Piston compressor for compressing a gas, which is optionally separable by means of a coupling of a drive device. The reciprocating compressor has an intake valve disposed between a gas to be compressed inlet line and a compression space of the reciprocating compressor, and an exhaust valve disposed between the compression space of the reciprocating compressor and a compressed gas discharge line. Furthermore, the reciprocating compressor has a venting device, through which compressed gas from the compression space can be discharged.

Description

The invention relates to a piston compressor for compressing a gas, which is optionally separable by means of a coupling of a drive device, with an inlet valve which is arranged between an inlet line for gas to be compressed and a compression chamber of the piston compressor and an outlet valve, which between the compression chamber of the piston compressor and a compressed gas outlet pipe.

Such compressors are used for example for the compressed air supply of commercial vehicles, in particular for the compressed air supply of the brake system. The drive of the compressor is carried out via the drive train of the internal combustion engine. There are known applications in which between the compressor and the drive connection, a clutch is arranged to separate the compressor from the drive when the compressed air system of the commercial vehicle is filled with compressed air. In known embodiments, the discharge line of the compressor is emptied simultaneously with the opening of the clutch. When restarting the compressor, the pressure in the then pressure-free outlet line must first be rebuilt before compressed air can be supplied to the compressed air system. To avoid such efficiency losses, solutions are also known in which the outlet line is not switched pressure-free, while the reciprocating compressor is not driven.

In reciprocating compressors of the type mentioned there is the danger that an exhaust valve is leaking due to contamination such as deposits by lubricating oil residues or in particular of such dissolved particles. In this case, the exhaust valves often have a valve tongue, between which and the valve seat such contaminants can get there and prevent the complete closing of the valve. For example, in the event of a leakage of an exhaust valve resulting therefrom in conjunction with a pressurized exhaust line during separation of the compressor from the engine, compressed air may return to the compression space of the compressor. The pressure in the compression chamber of a reciprocating compressor in a 12.5 bar system can then rise to up to 6 bar. When restarting the reciprocating compressor with such a high pressure in the compression chamber results in the first compression stroke of the piston, a compression of the gas in the compression chamber to about 60 bar. The torque occurring here is far too high for the clutch, which slips in this case, overheated and excessively excessive wear. In addition, such a high pressure in the compression chamber can also lead to damage to the compressor itself.

The invention is therefore based on the object to provide an improved reciprocating compressor, which avoids the aforementioned disadvantages and the resulting undesirable effects.

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

To solve the problem, a piston compressor for compressing a gas is proposed, which is optionally separable by means of a coupling of a drive device, with an inlet valve which is arranged between an inlet line for gas to be compressed and a compression chamber of the reciprocating compressor and an outlet valve, which between the Compression space of the reciprocating compressor and a discharge line for compressed gas is arranged. The reciprocating compressor has a venting device, through which compressed gas can be discharged from the compression space, which passes from the outlet line back into the compression space during the separation of the reciprocating compressor from the drive device.

Such a reciprocating compressor has an inlet line, which is in particular part of an inlet system and through which a gas to be compressed is guided to a compression space of the reciprocating compressor. In this case, an inlet valve is arranged between the inlet line and the compression space, which is open during the intake of gas to be compressed into the compression space (the pressure in the compression space is lower than the pressure in the inlet line). During the compression of the gas in the compression space (the pressure in the compression space is higher than the pressure in the intake pipe), the intake valve closes the compression space opposite to the intake pipe.

Between the compression space and the outlet conduit, an outlet valve is arranged which is open when the compressed gas is expelled from the compression space (the pressure in the compression space is higher than the pressure in the outlet conduit), thus defining a connection between the compression space and the outlet conduit. The outlet valve closes the connection between the compression chamber and the outlet line during the suction of gas to be compressed into the compression chamber (the pressure in the compression chamber is lower than the pressure in the outlet line), and a return flow of compressed gas from the outlet pipe into the compression space to prevent.

Both intake and exhaust valves of reciprocating compressors often employ valves with a closing body that is forced onto the valve seat depending on the pressure difference on either side of the valve and thereby closes or lifts off the valve seat, thereby opening the valve. A common type of such valves has a serving as a closing body valve tongue.

The piston compressor according to the invention has a venting device, through which compressed gas from the compression chamber can be discharged in order to lower the pressure therein. In this case, in particular compressed gas is discharged, which passes during a separation of the reciprocating compressor of the drive means in particular by a not completely closing exhaust valve from the pressurized outlet line back into the compression space and there causes an increase in pressure.

In one embodiment of the reciprocating compressor, the compressed gas is discharged by means of the venting device from the compression chamber in a region of lower pressure, in particular ambient pressure. Thus, the compressed gas can escape into a region which has a lower pressure than the compression space, in which compressed gas has penetrated from the outlet line. As a result of the discharge of the compressed gas, the pressure in the compression chamber decreases.

In one embodiment of the reciprocating compressor, the region is formed with the ambient pressure from the environment itself, a gas space connected to the inlet system or the inlet line or the interior of the crankcase of the reciprocating compressor. An area with ambient pressure in the inlet system can be, for example, the inlet line or a gas space connected to it, which is formed, for example, in the cylinder head of the piston compressor and thus also forms part of the inlet line. In one embodiment, in which the area is formed with the ambient pressure from the interior of the crankcase of the reciprocating compressor, the gas flowing through the venting device from the compression chamber of the reciprocating compressor gas is guided into the crankcase, where in particular first a pressure equalization in the crankcase and then via the venting system with the environment takes place.

In this case, pressure fluctuations can occur both in a gas chamber connected to the intake system and in the crankcase of the reciprocating compressor: in the intake system, in particular depending on the Frischgasansaugung - for example, if the intake system in conjunction with the intake system of a correspondingly large-sized engine - or due in particular previous crank drive movements in the crankcase , However, since both the intake system and the crankcase are in communication with the environment and there is usually a constant balance of pressure fluctuations with the environment, the pressure prevailing in a gas space connected to the intake system or in the crankcase in the context of this invention is considered as ambient pressure ,

In one embodiment of the reciprocating compressor, a switchable valve device forms the venting device, by means of which compressed gas from the compression space can be discharged by a connection of the compression chamber with a region of lower pressure, in particular ambient pressure can be produced.

This can be a switchable valve device, by means of which, via an example arranged in the valve plate or in the cylinder wall vent opening of the compression chamber of the reciprocating compressor is optionally connectable to a region of lower pressure, in particular ambient pressure. For this purpose, in particular a 2/2-way valve can be used which, for example, is so switchable that it opens and closes in particular parallel or offset with the actuation of the clutch and thus enables a pressure equalization in the compression chamber by the discharge of compressed gas, as long as the Piston compressor is not driven. However, it can also be provided to also switch such a valve device as a function of other parameters, such as, for example, the pressure actually prevailing in the compression space, which pressure is detected by pressure sensors connected thereto or in another suitable manner.

Another embodiment of the reciprocating compressor has a pilot-operated check valve, which also assumes the function of the intake valve. Such a pilot-operated check valve represents a switchable valve device which is arranged between the inlet line and the compression space of the compressor and in particular automatically opens and closes the connection between the inlet line and the compression space in accordance with the function of an inlet valve. In addition, such a pilot-operated check valve is a switchable valve device, by means of which the connection between the inlet line and the compression chamber optionally open and is closable to allow a pressure reduction by a discharge of compressed gas from the compression space.

For example, such a releasable check valve as well as the previously described switching valve in parallel or offset from the clutch operation switchable or in response to other, in particular with the pressure in the compression chamber related parameters, which are detected for example by means of sensors. With an opening of the inlet valve in the form of a pilot-operated check valve during a standstill of the compressor, a pressure equalization between the compression chamber and the inlet system take place, so that no significant pressure build-up can take place in the compression chamber.

In a further embodiment of the reciprocating compressor forms a non-return valve, the venting device, by means of which compressed gas from the compression space can be discharged. Such a check valve is in particular designed so that it then opens and connects the compression chamber with a region of lower pressure, in particular ambient pressure, when the pressure in the compression chamber due to a compressed during a separation of the piston compressor from the drive line from the discharge line back into the compression chamber arrived compressed Gas during a first compression stroke increases so much that threatens damage to the reciprocating compressor or a device connected to the reciprocating compressor. In this case, the check valve establishes a connection of the compression space with a region of lower pressure, in particular ambient pressure, whereby the compressed gas, which has passed from the outlet line back into the compression space during a separation of the piston compressor from the drive device, can be discharged. Thus, the pressure in the compression chamber during the first compression stroke of the reciprocating compressor after closing the clutch despite an increased pressure in the compression chamber by a compressed gas penetrated there does not rise above a set by the check valve maximum value.

In a further embodiment, the inlet valve forms the venting device. The inlet valve is designed such that a connection between the inlet line and the compression chamber can be closed only from a pressure in the compression chamber, which is at least 0.1 bar, preferably at least 0.2 bar and in particular at least 0.5 bar higher than that Pressure in the inlet pipe, which corresponds substantially to the ambient pressure. In this case, at a pressure in the compression chamber, which is below the limit of at least 0.1 bar, preferably at least 0.2 bar and in particular at least 0.5 bar overpressure, there is a continuing connection between the inlet line and the compression space. Thus, a compressed gas that enters the compression chamber during a separation of the piston compressor from the drive device, ie at standstill of the piston compressor, through this opening of the inlet valve in the inlet line can be discharged without a pressure build-up in the compression chamber of the compressor.

In one embodiment of the reciprocating compressor, in which the inlet valve is closed only from a predetermined pressure in the compression chamber, the inlet valve has a concave valve seat in particular on the valve plate and a substantially planar formed valve tongue, so that the valve tongue only after one by a pressure caused in the compression space elastic deformation sealingly against the valve seat. In such an embodiment, the inlet valve closes only when a sufficiently high pressure acts in the compression space during the compression stroke, which deforms the valve tongue so that it bears sealingly against the concave valve seat. As long as the pressure in the compression chamber is lower than the pressure that causes the inlet valve to close, the inlet valve is open. Thus, by compressed gas, which passes during the separation of the reciprocating compressor from the drive means from the outlet line back into the compression space, no pressure build-up in the compression chamber can be effected.

In another embodiment of the reciprocating compressor, in which the inlet valve can be closed only from a predetermined pressure in the compression chamber, the inlet valve has a flat valve seat and a bent valve tongue. Consequently, the valve tongue is sealingly attached to the valve seat only after an elastic deformation caused by the pressure in the compression space. Also in this embodiment, the inlet valve closes only when during a compression stroke, a sufficiently high pressure acts in the compression space, which deforms the bent valve tongue designed such that it rests sealingly against the flat valve seat. Again, the inlet valve remains open as long as the pressure in the compression chamber has a lower value than the pressure, which leads in particular during a compression stroke to close the inlet valve. Thus, even in this embodiment, a compressed gas that passes from the outlet line back into the compression chamber during the separation of the piston compressor from the drive means, leading to any pressure build-up in the compression chamber.

In another embodiment of the reciprocating compressor, a venting channel forms the venting device. By such a vent channel, which in particular produces a permanent connection to an area with respect to the compression space lower pressure, in particular ambient pressure, gas from one end of the vent passage in the compression space, which is at a higher pressure, through the vent passage in a region with less Pressure, in particular ambient pressure to be dissipated at the other end of the vent channel. As a result, a pressure equalization takes place with the compression chamber. If, therefore, during a separation of the piston compressor from the drive device gas from the pressurized outlet line passes back into the compression space, there can be no increased pressure build up because the gas is discharged through the vent channel.

In one embodiment, at least one end of the vent passage is disposed in the valve plate and in particular establishes a connection of the compression space to the surroundings of the reciprocating compressor or to its inlet system. A disadvantage of a permanently open venting channel is that it also allows for escape of the gas from the compression chamber during a compression stroke, whereby the efficiency of the compressor is reduced. In one embodiment, however, the vent channel has such a small cross-section that a pressure equalization through the vent channel is possible, the throttling action of the small cross-section of the vent passage but prevents the pressure flow of a larger volume flow during a compression stroke.

An alternative design which restricts escape of the gas from the compression space during a compression stroke has a suitable check valve in the vent passage, which closes it from a predetermined overpressure. A suitable check valve is for example a gravity ball valve. Advantageously, such a check valve is robust against contamination by lubricating oil contaminants.

In another embodiment, at least one end of the venting channel is arranged in the cylinder wall, which establishes, for example, a connection with the surroundings of the reciprocating compressor. Starting from the outside of the cylinder wall, the venting channel may have a connecting device in the form of a line which serves as an extension of the venting channel and connects it in particular to the inlet system or to the interior of the crankcase of the reciprocating compressor. Such a venting channel also forms an opening in the compression chamber, through which gas can escape from the compression chamber even during the compression stroke, with the result that the efficiency of the piston compressor drops. The venting channel is therefore designed, in particular, large enough to ensure pressure equalization, so that gas volume flow, which can thereby be removed from the compression space by the drive device during a separation of the compressor, is at least as great as that from the outlet line in this time period the compression space reached gas volume flow of compressed gas from the outlet.

In one embodiment, the venting channel is arranged in the cylinder wall so that one end passes from the piston during the compression stroke from a certain piston position and thus is closed. This is the case in particular when the venting channel is arranged between an average stroke position of the piston and its top dead center. By virtue of this arrangement of the venting channel, gas which has returned from the outlet channel back into the compression chamber during a standstill of the piston compressor can be discharged in order to prevent pressure build-up in the compression chamber. At the same time, escape of gas from the compression space is prevented as soon as a piston ring has passed through the opening of the ventilation channel during the movement towards top dead center.

In one embodiment of the reciprocating compressor, a check valve or a check valve is arranged in the venting channel or in a connecting device connected thereto. On the one hand, such a check valve can prevent the escape of gas during a compression stroke of the piston compressor from the compression chamber, and on the other hand, such a check valve can also serve to prevent the intake of potentially contaminated gas, in particular from the crankcase, into the compression chamber.

Although the piston, the cylinder, the cylinder head, etc. have been previously addressed in connection with the components of the reciprocating compressor, the characteristics described herein apply to a reciprocating compressor having two or more of these elements, since the present invention is not limited to single-stage reciprocating compressors but also for multi-stage reciprocating compressors can be used.

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

In the figures show:

1 a schematic representation of an exemplary piston compressor of the prior art;

2 a representation of an exemplary exhaust valve as used in piston compressors in the prior art;

3 a schematic representation of a first exemplary embodiment of a piston compressor according to the invention, in which the venting device comprises a switchable valve device;

4 a schematic representation of a second exemplary embodiment of a piston compressor according to the invention, in which the venting device comprises a switchable valve device;

5 a schematic representation of a third exemplary embodiment of a piston compressor according to the invention, in which the venting device comprises a check valve;

6 a schematic representation of a fourth exemplary embodiment of a piston compressor according to the invention, in which the venting device has a vent channel;

7 a schematic representation of a fifth exemplary embodiment of a piston compressor according to the invention, in which the venting device comprises a vent channel with check valve;

8th a schematic representation of a sixth exemplary embodiment of a piston compressor according to the invention, in which the venting device comprises a venting channel;

9 a schematic representation of a seventh exemplary embodiment of a piston compressor according to the invention, in which the venting device comprises a venting channel;

10 a schematic representation of an eighth exemplary embodiment of a piston compressor according to the invention in which the venting device comprises a venting channel; and

11 a representation of a detail of a ninth exemplary embodiment of a piston compressor according to the invention, in which the inlet valve forms the venting device.

1 shows a schematic representation of an exemplary reciprocating compressor 10 as known as the prior art. The crankshaft 11 of the reciprocating compressor 10 is about a clutch 3 with a drive device (not shown, here an internal combustion engine) connected and by means of the coupling 3 optionally separable from this drive device. With the clutch open 3 Thus, no torque is applied to the crankshaft 11 of the reciprocating compressor 10 transferred so that the crankshaft 11 during the separation of the reciprocating compressor 10 from the drive device stands still.

The crankshaft 11 is with an eccentrically mounted connecting rod 12 connected to which a piston 13 is stored. The piston 13 is axially movable in a cylinder 14 of the reciprocating compressor 10 stored. The at least one crankshaft 11 , a connecting rod 12 and a piston 13 having crank mechanism 15 is in a crankcase 16 arranged, which firmly with the cylinder 14 connected is. By a rotary motion of the crankshaft 11 becomes the piston 13 from the connecting rod 12 so in the cylinder 14 moves that it performs a lifting movement.

Above the piston 13 is the cylinder 14 through a valve plate 20 locked. This defines the cylinder 14 , The piston 13 and the valve plate 20 the compression space 17 in the cylinder 14 , At the valve plate 20 is an inlet valve 21 arranged between an inlet pipe 22 and the compression room 17 is arranged. The inlet pipe 22 is part of an intake system 23 , the fresh air from the environment through a filter (not shown) sucks and the inlet line 22 through the cylinder head (not shown) the compression space 17 supplies. The cylinder head is above the valve plate 20 arranged and has a cylinder head volume 24 on, which via the inlet valve 21 with the compression space 17 communicates. The inlet valve 21 is designed as a check valve, which is a suction of fresh air in the compression chamber 17 allows, but a back flow over the inlet line 22 in the compression room 17 sucked air prevented.

At the valve plate 20 is also an exhaust valve 26 arranged between the compression space 17 and an outlet conduit 27 is arranged. Via the outlet pipe 27 is compressed gas, here air, fed to a compressed air storage, not shown here. The outlet valve prevents this 26 , which is also designed as a check valve, a back flow of compressed air from the outlet pipe 27 in the compression room 17 ,

2 shows a representation of an exemplary exhaust valve 26 as in piston compressors 10 is commonly used in the art. The outlet valve 26 is on the valve plate 20 of the reciprocating compressor 10 above the compression chamber 17 arranged. The valve plate 20 has an outlet opening 28 on which the compression space 17 with one in valve plate 20 and cylinder head of the reciprocating compressor 10 arranged cylinder head volume 27a connects, which forms part of the outlet pipe 27 forms.

The outlet valve 26 has a valve tongue as a valve body 26a which, starting from a predetermined pressure difference between the compression space 17 and the outlet pipe 27 from the valve seat 26b releases and a flow of air from the compression chamber 17 in the outlet pipe 27 allows. The outlet valve 26 also has a above the outlet opening 28 arranged investment element 26c on, on which the valve tongue 26a in the open state is present. As soon as the valve tongue 26a from the valve seat 26b releases the pressurized air from the compression chamber 17 through the lateral open areas on the valve tongue 26a and the contact element 26c past the outlet pipe 27 stream.

Get impurities out of the compression chamber 17 or from the cylinder head volume 27a , for example, of forming deposits by residues in the air flowing through the hot top of the piston 13 , the valve plate 20 or the cylinder head volume 27a release, between the valve tongue 26a and the valve seat 26b , there is a risk that the exhaust valve 26 no longer completely closes. In this case, compressed air may be discharged from the outlet pipe 27 in the compression room 17 flow back as soon as the pressure in the compression chamber 17 under the pressure in the outlet pipe 27 sinks. In a 12.5 bar compressed air system of a commercial vehicle, the compression chamber 17 of the reciprocating compressor 10 For example, be acted upon by the back-flowing air at a pressure of up to 6 bar. Will the piston compressor 10 then reconnected to the drive means, the piston compressor generates 10 at the first stroke an internal pressure of about 60 bar. Unless the compression space 17 this enormous internal pressure is the case on the crankshaft 11 resulting torque for the clutch 3 usually much too high, so that it slips, overheats and excessively fast wears.

3 shows a schematic representation of a first exemplary embodiment of a piston compressor according to the invention 10 , The construction of the reciprocating compressor 10 in 3 corresponds largely to the structure of 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. Below are just the differences of the reciprocating compressor 10 out 3 opposite the piston compressor 10 out 1 explained.

The in 3 illustrated piston compressor 10 has a venting device in the form of a 2/2-way valve 31 on that between the compression space 17 and the intake system 23 is arranged. The 2/2-way valve is a switchable valve device. In the embodiment in 3 is the control line 31a of the 2/2-way valve 31 with the control of the clutch 3 signal-connected. Will the clutch 3 opened and the piston compressor 10 so that no longer driven, the 2/2-way valve 31 switched from the illustrated closed position to an open position to an air-flow-through connection between the compression space 17 and the intake system 23 manufacture.

Now arrives during the standstill of the reciprocating compressor 10 For example, in the case of a no longer tightly closing exhaust valve 26 compressed air in the compression chamber 17 , so can through the open 2/2-way valve 31 a pressure equalization with the inlet pipe 22 occur. Thus, no pressure build-up in the compression chamber 17 take place, in particular during the first compression stroke of the reciprocating compressor 10 when it is restarted to damage the piston compressor 10 and / or the clutch 3 could lead.

4 shows a schematic representation of a second exemplary embodiment of a piston compressor according to the invention 10 , Also the construction of the piston compressor 10 in 4 corresponds largely to the structure of 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. Below are just the differences of the reciprocating compressor 10 out 4 opposite the piston compressor 10 out 1 explained.

The in 4 illustrated piston compressor 10 has a venting device in the form of a pilot-operated check valve 32 on, which also serves as an inlet valve. This is the unlockable check valve 32 between the compression space 17 and the intake system 23 arranged. During the intake of fresh air from the inlet pipe 22 in the compression room 17 opens the pilot operated check valve 32 due to the applied pressure difference automatically. In the pilot operated check valve 32 it is also one switchable valve device, which in addition to the automatic opening during the intake of fresh air and by means of a control signal in an open position is switchable. In the embodiment in 4 is the control line 32a the pilot operated check valve 32 signal-connected with a control device, not shown. Depending on at least one predetermined parameter, such as the pressure in the compression space 17 , so that the unlockable check valve 32 opened to a connection between the compression space 17 and the inlet pipe 22 manufacture.

Now arrives during the standstill of the reciprocating compressor 10 For example, in the case of a no longer tightly closing exhaust valve 26 compressed air in the compression chamber 17 , so the pilot-operated check valve 32 be opened to pressure equalization with the inlet pipe 22 to enable. Thus, no pressure buildup in the compression chamber 17 take place, in particular during the first compression stroke of the reciprocating compressor 10 when it is restarted to damage the piston compressor 10 and / or the clutch 3 could lead.

When restarting the reciprocating compressor 10 becomes the pilot operated check valve 32 switched back by the control device in the working position, in which it is in the intake of fresh air from the inlet pipe 22 in the compression room 17 opens automatically due to the applied pressure difference.

5 shows a schematic representation of a third exemplary embodiment of a piston compressor according to the invention 10 , Also the construction of the piston compressor 10 in 5 corresponds largely to the structure of 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. Below are just the differences of the reciprocating compressor 10 out 5 opposite the piston compressor 10 out 1 explained.

The in 5 illustrated piston compressor 10 has a venting device in the form of a check valve 33 on that between the compression space 17 and the intake system 23 is arranged. That in addition to the inlet valve 21 between the compression space 17 and the intake system 23 arranged check valve 33 locks in to the inlet valve 21 opposite direction, so that this during the intake of fresh air into the compression chamber 17 as well as during compression in normal operation of the reciprocating compressor 10 closed is.

If at the in 5 shown embodiment during standstill of the reciprocating compressor 10 For example, in the case of a no longer tightly closing exhaust valve 26 compressed air in the compression chamber 17 first finds a pressure build-up in the compression chamber 17 instead of. The resulting pressure does not reach a higher value than during a compression stroke, so that initially no venting of the compression chamber 17 is required. Only at the first compression stroke of the reciprocating compressor 10 after its re-commissioning arises due to the pre-compressed air in the compression chamber 17 a significantly increased pressure, resulting in damage to the reciprocating compressor 10 and / or the clutch 3 can lead. The check valve 33 is therefore designed so that there is a connection between the compression space 17 and the inlet pipe 21 with a sufficiently large cross-section opens to air from the compression chamber 17 as soon as the pressure in the compression chamber 17 exceeds a critical value. In the exemplary reciprocating compressor 10 for a commercial vehicle, the peak pressure in the compression chamber during normal operation is between about 16 and 19 bar. An exemplary check valve 33 is therefore designed so that, for example, at a pressure of 20 bar in the compression chamber 17 opens and so compressed air from the compression chamber 17 dissipates.

6 shows a schematic representation of a fourth exemplary embodiment of a piston compressor according to the invention 10 , Also the construction of the piston compressor 10 in 6 corresponds largely to the structure of 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. Below are just the differences of the reciprocating compressor 10 out 6 opposite the piston compressor 10 out 1 explained.

The in 6 illustrated piston compressor 10 has a venting device in the form of a venting channel 34 on that between the compression space 17 and the intake system 23 is arranged. The ventilation duct 34 provides an air-flowable connection between the compression space 17 and the intake system 23 so that during a standstill of the reciprocating compressor no pressure in the compression chamber 17 can build, which is significantly above the ambient pressure.

In the in 6 embodiment shown is the vent channel 34 in the area of the valve plate 20 at the top of the cylinder 14 arranged so that through the venting channel 34 a constant pressure equalization with the inlet line 32 of the reciprocating compressor 10 he follows. If during a standstill of the reciprocating compressor 10 compressed air from the outlet pipe 27 in the compression room 17 passes through the venting channel 34 a pressure equalization with the inlet pipe 22 instead, whereby no pressure build-up in the compression chamber 17 can be done. A disadvantage of such a venting channel 34 however, this is also during a compression stroke of the reciprocating compressor 10 is open and in this phase to be compressed air from the compression chamber 17 escapes. This lowers the efficiency of the reciprocating compressor 10 , The ventilation duct 34 is therefore designed so that it has only a small cross-section to ensure adequate pressure compensation during standstill of the reciprocating compressor 10 with the intake system 23 on the other hand, however, has a throttling effect at high pressures in order to limit the volume flow of the discharged air.

7 shows a schematic representation of a sixth exemplary embodiment of a piston compressor according to the invention 10 , The construction of the reciprocating compressor 10 in 7 corresponds largely to the structure of in 6 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. Below are just the differences of the reciprocating compressor 10 out 7 opposite the piston compressor 10 out 6 explained.

In 7 is a piston compressor 10 also shown a venting device in the form of a vent channel 39 that is between the compression space 17 and the intake system 23 is arranged. In the ventilation duct 39 is a check valve in the form of a gravity ball valve 40 arranged, which the venting channel 39 then closes when the pressure in the compression chamber 17 exceeds a predetermined value which the ball of the gravity ball valve 40 against their gravity at a top of the gravity ball valve 40 arranged valve seat presses. By the check valve is thus an escape of compressed air from the compression chamber 17 restricted during a compression stroke.

8th shows a schematic representation of a sixth exemplary embodiment of a piston compressor according to the invention 10 , The construction of the reciprocating compressor 10 in 8th corresponds largely to the structure of in 6 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. Below are just the differences of the reciprocating compressor 10 out 8th opposite the piston compressor 10 out 6 explained.

Also the in 8th illustrated piston compressor 10 has a venting device in the form of a venting channel 35 on that between the compression space 17 and the intake system 23 is arranged. In contrast to the reciprocating compressor 10 out 6 is the venting channel 35 in the upper part of the wall of the cylinder 14 arranged. Also the venting channel 35 provides an air-flowable connection between the compression space 17 and the cylinder head volume 24 ago, the pressure equalization between the compression chamber 17 and the intake system 23 allows.

As in 8th is shown, the vent channel 35 be arranged approximately in the region which the upper piston ring about 60 ° before the top dead center of the piston 13 sweeps. This will be during the stoppage of the reciprocating compressor 10 a discharge of compressed air from the compression space 17 reached, coming out of the outlet 27 get there while the piston compressor 10 is separated from the drive device. At the same time, however, prevents the air in the compression chamber 17 escapes during the final phase of the compression stroke.

9 shows a schematic representation of a seventh exemplary embodiment of a piston compressor according to the invention 10 , The construction of the reciprocating compressor 10 in 9 corresponds largely to the structure of in 8th 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. Below are just the differences of the reciprocating compressor 10 out 9 opposite the piston compressor 10 out 8th explained.

The in 9 illustrated piston compressor 10 has a venting device in the form of a venting channel 36 on that between the compression space 17 and the interior of the crankcase 16 is arranged. As with the piston compressor 10 out 8th is the venting channel 36 in the upper part of the wall of the cylinder 14 arranged. This provides an air-flowable connection between the compression space 17 and the crankcase 16 ago. Because the crankcase 16 of the reciprocating compressor 10 allows pressure equalization relative to the environment prevails in the interior of substantially ambient pressure. This can be done via the venting channel 36 a pressure equalization between the compression chamber 17 and the crankcase 16 respectively.

10 shows a schematic representation of an eighth exemplary embodiment of a piston compressor according to the invention 10 , The construction of the reciprocating compressor 10 in 10 corresponds largely to the structure of in 9 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. Below are just the differences of the reciprocating compressor 10 out 10 opposite the piston compressor 10 out 9 explained.

The in 10 illustrated piston compressor 10 has a venting device in the form of a venting channel 37 on, according to the ventilation duct 36 out 9 between the compression space 17 and the interior of the crankcase 16 is arranged. Opposite the ventilation channel 36 out 9 is in the venting channel 37 a check valve 38 arranged, which provides a return flow of air from the crankcase 16 in the compression room 17 prevented. The check valve 38 can be designed so that it already at a low pressure difference between the pressure in the compression chamber 17 and the pressure in the crankcase 16 opens to build up pressure in the compression chamber 17 during a service life of the reciprocating compressor 10 to prevent.

11 shows a representation of a detail of a ninth exemplary embodiment of a piston compressor according to the invention 10 in which the inlet valve 21 forms the venting device. The elements of the inlet valve 21 are in 11 shown in exploded view. The inlet valve 21 forms the upper end of the compression space 17 in the cylinder 14 , The valve tongue 21a is integral with a first element of the inlet valve 21 executed, which between the cylinder 14 and an investment element 21b of the inlet valve 21 is arranged. The exemplified investment element 21b has two valve openings 21c which depends on the pressure difference between the compression space 17 in the cylinder 14 and the pressure in the inlet system 23 from the valve tongue 21a be closed.

The valve tongue 21a has a curvature that is designed such that the valve tongue 21a from a pressure in the compression chamber 22 on the contact element 21b abuts (dashed line of the valve tongue 21a ) which in the exemplary embodiment is 0.4 bar higher than the pressure in the inlet system 23 (Ambient pressure) and thereby the valve openings 21c closes. At a pressure difference of less than 0.4 bar, the valve tongue 21a always make a curvature on that connection between the inlet system 23 and the compression room 17 consists. So is a compressed gas that enters the compression chamber 17 has passed through the valve openings 21c of the inlet valve 21 in the inlet pipe 22 removable, without any pressure build-up in the compression chamber 17 of the compressor 10 he follows.

In another, not shown but acting in the same way embodiment of the reciprocating compressor 10 can the inlet valve 21 also an investment element 21b in the area of the valve openings 21c having a recess, so that the valve tongue 21a also in this embodiment only from a predetermined pressure in the compression chamber 17 sealing on the contact element 21b is applied.

LIST OF REFERENCE NUMBERS

3

clutch

10

piston compressor

11

crankshaft

12

pleuel

13

piston

14

cylinder

15

crankshaft

16

crankcase

17

compression chamber

20

valve plate

21

intake valve

21a

valve tongue

21b

contact element

21c

valve opening

22

inlet line

23

intake system

24

Cylinder head volume (inlet)

26

outlet valve

26a

valve tongue

26b

valve seat

26c

contact element

27

outlet pipe

27a

Cylinder Head Volume (Outlet)

28

outlet

31

2/2 way valve

31a

control line

32

check valve

32a

control line

33

check valve

34

vent channel

35

vent channel

36

vent channel

37

vent channel

38

check valve

39

check valve

40

Gravity ball valve

Claims (10)

Piston compressor for compressing a gas, optionally by means of a coupling ( 3 ) is separable from a drive device, with an inlet valve ( 21 ), which between an inlet line ( 22 ) for gas to be compressed and a compression chamber ( 17 ) of the reciprocating compressor ( 10 ) is arranged and an exhaust valve ( 26 ), which between the compression space ( 17 ) of the reciprocating compressor ( 10 ) and an outlet line ( 27 ) is arranged for compressed gas, characterized characterized in that the reciprocating compressor ( 10 ) a venting device ( 31 . 32 . 33 . 34 . 35 . 36 . 37 . 39 ), through which compressed gas, during the separation of the reciprocating compressor ( 10 ) from the drive device from the outlet line ( 27 ) back into the compression chamber ( 17 ), from the compression chamber ( 17 ) is dissipatable. Piston compressor according to claim 1, characterized in that the compressed gas from the compression chamber ( 17 ) can be diverted into an area with ambient pressure which is from the environment itself, one with the inlet system ( 23 ) connected gas space ( 22 . 24 ) or the interior of the crankcase ( 16 ) is formed. Piston compressor according to one of the preceding claims, characterized in that a switchable valve device ( 31 . 32 ) forms the venting device. Piston compressor according to one of claims 1 or 2, characterized in that a check valve ( 33 ) forms the venting device. Piston compressor according to one of claims 1 or 2, characterized in that the inlet valve ( 21 ) forms the venting device, wherein the inlet valve ( 21 ) is formed so that with it a connection between the inlet line ( 22 ) and the compression space ( 17 ) only from a predetermined pressure in the compression chamber ( 17 ), wherein the predetermined pressure is at least 0.1 bar, preferably at least 0.2 bar and in particular at least 0.5 bar higher than the pressure in the inlet line ( 22 ). Piston compressor according to claim 5, characterized in that the inlet valve ( 21 ) has a concave valve seat and a substantially flat formed valve tongue, so that the valve tongue only after a by the pressure in the compression chamber ( 17 ) caused elastic deformation sealingly against the valve seat. Piston compressor according to claim 5, characterized in that the inlet valve ( 21 ) has a newly formed valve seat and a bent valve tongue, so that the valve tongue only after a by the pressure in the compression chamber ( 17 ) caused elastic deformation sealingly against the valve seat. Piston compressor according to one of claims 1 or 2, characterized in that a venting channel ( 34 . 35 . 36 . 39 ) forms the venting device. Piston compressor according to claim 8, characterized in that at least one end of the venting channel ( 34 . 35 . 36 . 39 ) in the valve plate ( 20 ) or in the cylinder wall ( 14 ) is arranged. Piston compressor according to one of claims 8 or 9, characterized in that in the venting channel ( 34 . 35 . 36 . 39 ) a check valve ( 38 ) or a check valve ( 40 ) is arranged.

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