U.S. patent application number 16/136908 was filed with the patent office on 2019-01-17 for piston compressor with a closing device for the outlet line.
The applicant listed for this patent is KNORR-BREMSE Systeme fuer Nutzfahrzeuge GmbH. Invention is credited to Gilles HEBRARD, Wolfgang KIENER, Jean-Baptiste MARESCOT, Joerg MELLAR, Michel SAINTIVE, Thomas WEINHOLD.
Application Number | 20190017498 16/136908 |
Document ID | / |
Family ID | 58401583 |
Filed Date | 2019-01-17 |
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United States Patent
Application |
20190017498 |
Kind Code |
A1 |
HEBRARD; Gilles ; et
al. |
January 17, 2019 |
Piston Compressor with a Closing Device for the Outlet Line
Abstract
A piston compressor for compressing a gas, which optionally can
be disconnected from a drive device by a clutch, has 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 is arranged between the compression chamber
of the piston compressor and an outlet line for compressed gas. The
piston compressor includes a closing device which closes the outlet
line with respect to the compression chamber.
Inventors: |
HEBRARD; Gilles; (Lisieux,
FR) ; KIENER; Wolfgang; (Muenchen, DE) ;
MARESCOT; Jean-Baptiste; (Manerbe, FR) ; MELLAR;
Joerg; (Pliening, DE) ; SAINTIVE; Michel; (Le
Pre d'Auge, FR) ; WEINHOLD; Thomas; (Muenchen,
DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
KNORR-BREMSE Systeme fuer Nutzfahrzeuge GmbH |
Muenchen |
|
DE |
|
|
Family ID: |
58401583 |
Appl. No.: |
16/136908 |
Filed: |
September 20, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/EP2017/056910 |
Mar 23, 2017 |
|
|
|
16136908 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F04B 49/03 20130101;
F04B 39/123 20130101; F04B 41/02 20130101; F04B 2201/124 20130101;
F04B 39/08 20130101; F04B 2201/1241 20130101; F04B 49/225
20130101 |
International
Class: |
F04B 39/08 20060101
F04B039/08; F04B 39/12 20060101 F04B039/12; F04B 41/02 20060101
F04B041/02; F04B 49/03 20060101 F04B049/03; F04B 49/22 20060101
F04B049/22 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 21, 2016 |
DE |
10 2016 105 148.9 |
Claims
1. A piston compressor for compressing a gas, comprising: an inlet
valve, which is arranged between an inlet line for gas for
compression and a compression chamber of the piston compressor; an
outlet valve, which is arranged between the compression chamber of
the piston compressor and an outlet line for compressed gas; a
separate closing device, which is arranged downstream of the outlet
valve in a flow direction of the gas by which the outlet line is
closable with respect to the compression chamber; a clutch by which
the piston compressor is separable from a drive device; and a
control device which has a signal connection both to the clutch and
to the separate closing device; wherein a switchable valve device
forms the closing device, and the control device is configured to
switch the switchable valve device into a closed position when the
clutch between the piston compressor and the drive device is
open.
2. The piston compressor as claimed in claim 1, wherein the
switchable valve device closes the outlet line in a manner
dependent on the pressure difference prevailing at the two sides of
the switchable valve device.
3. The piston compressor as claimed in claim 2, wherein the
switchable valve device is configured so as to switch into a closed
position simultaneously with the opening of the clutch.
4. The piston compressor as claimed in claim 1, wherein a 2/2-way
valve forms the switchable valve device.
5. The piston compressor as claimed in claim 1, wherein the
switchable valve device is configured so as to switch into a closed
position simultaneously with the opening of the clutch.
6. A method for operating a piston compressor for compressing a
gas, the piston compressor having an inlet valve arranged between
an inlet line for gas for compression and a compression chamber,
and having an outlet valve arranged between the compression chamber
and an outlet line for compressed gas, the method comprising the
acts of: determining when a clutch arranged between the piston
compressor and a drive device is open; and switching, via a control
device having a signal connection both to the clutch and to a
switchable valve device arranged downstream of the outlet valve in
a flow direction of the gas, the switchable valve device into a
closed position when the clutch between the piston compressor and
the drive device is open.
7. The method for operating a piston compressor as claimed in claim
6, wherein the control device switches the switchable valve device
into an open position when the clutch between the piston compressor
and the drive device is closed.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of PCT International
Application No. PCT/EP2017/056910, filed Mar. 23, 2017, which
claims priority under 35 U.S.C. .sctn. 119 from German Patent
Application No. 10 2016 105 148.9, filed Mar. 21, 2016, the entire
disclosures of which are herein expressly incorporated by
reference.
BACKGROUND AND SUMMARY OF THE INVENTION
[0002] The invention relates to a piston compressor for compressing
a gas, which piston compressor is optionally separable from a drive
device by means of a clutch, having an inlet valve, which is
arranged between an inlet line for gas for compression and a
compression chamber of the piston compressor, and having an outlet
valve, which is arranged between the compression chamber of the
piston compressor and an outlet line for compressed gas.
[0003] 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. Here, the compressor is driven by the
drivetrain of the internal combustion engine. Applications are
known in which a clutch is arranged between the compressor and the
drive connection in order to separate the compressor from the drive
when the compressed-air system of the commercial vehicle has been
charged with compressed air. In the case of known embodiments, the
outlet line of the compressor is evacuated simultaneously with the
opening of the clutch. Upon the resumption of operation of the
compressor, it is firstly necessary for the pressure in the then
unpressurized outlet line to be built up again before compressed
air can be delivered into the compressed-air system. To avoid such
efficiency losses, solutions are also known in which the outlet
line is not placed into an unpressurized state while the piston
compressor is not being driven.
[0004] In the case of piston compressors of the stated type, there
is the risk of an outlet valve developing leaks as a result of
contaminants such as coatings formed by lubricating oil residues
or, in particular, by particles dissolved in the same. Here, the
outlet valves commonly have a valve tongue, between which and the
valve seat thereof such contaminants can pass and, there, prevent
the complete closure of the valve. In the case of a resulting leak
of an outlet valve for example, in conjunction with a pressurized
outlet line, compressed air can pass back into the compression
chamber of the compressor during the separation of the compressor
from the drive. The pressure in the compression chamber of a piston
compressor in a 12.5 bar system may then rise up to 6 bar. Upon the
resumption of operation of the piston compressor with such a high
pressure in the compression chamber, a compression of the gas in
the compression chamber up to approximately 60 bar occurs as a
result during the first compression stroke of the piston. The
torque that arises here is far too high for the clutch, which in
this situation slips, overheats and is subject to excessively
intense wear. Furthermore, such a high pressure in the compression
chamber can also lead to damage to the compressor itself.
[0005] The invention is therefore based on the object of providing
an improved piston compressor which avoids the abovementioned
disadvantages and the undesired effects resulting therefrom.
[0006] To achieve said object, a piston compressor and a method for
operating a piston compressor are provided in accordance with
embodiments of the invention.
[0007] To achieve the object, a piston compressor for compressing a
gas is provided, which piston compressor is optionally separable
from a drive device by way of a clutch, having an inlet valve,
which is arranged between an inlet line for gas for compression and
a compression chamber of the piston compressor, and having an
outlet valve, which is arranged between the compression chamber of
the piston compressor and an outlet line for compressed gas. The
piston compressor has a separate closing device which is arranged
downstream of the outlet valve in a flow direction of the gas and
by which the outlet line can be closed off with respect to the
compression chamber during the time in which the piston compressor
is separated from the drive device.
[0008] A piston compressor of said type has an inlet line which is,
in particular, part of an inlet system and by which a gas for
compression is conducted to a compression chamber of the piston
compressor. Here, between the inlet line and the compression
chamber, there is arranged an inlet valve which is open while gas
for compression is being drawn into the compression chamber (the
pressure in the compression chamber is lower than the pressure in
the inlet line). During the compression of the gas in the
compression chamber (the pressure in the compression chamber is
higher than the pressure in the inlet line), the inlet valve closes
off the compression chamber with respect to the inlet line.
[0009] Between the compression chamber and the outlet line, there
is arranged an outlet valve which is open while the compressed gas
is being discharged from the compression chamber (the pressure in
the compression chamber is higher than the pressure in the outlet
line) and which thus defines a connection between the compression
chamber and the outlet line. The outlet valve closes the connection
between compression chamber and outlet line while gas for
compression is being drawn into the compression chamber (the
pressure in the compression chamber is lower than the pressure in
the outlet line), in order to prevent a backflow of compressed gas
from the outlet line into the compression chamber.
[0010] Both for inlet valves and for outlet valves of piston
compressors, use is commonly made of valves which have a closing
body which, in a manner dependent on the pressure difference on the
two sides of the valve, is pushed against the valve seat and thus
closes the valve or is lifted off the valve seat, whereby the valve
opens. A conventional type of construction of such valves has a
valve tongue which serves as closing body. It is however also known
for piston compressors to use inlet and outlet valves which have
switched valve bodies.
[0011] The piston compressor according to the invention has a
separate closing device arranged downstream of the outlet valve in
a flow direction of the gas. Said closing device is designed so as
to be suitable for closing off the outlet line in the direction of
the outlet valve in particular in gas-tight fashion. A backflow of
compressed gas from the outlet line back into the compression
chamber through an outlet valve that is possibly not reliably
closed can thus be prevented by means of the closed closing device.
The closing device is a device which is separate from the outlet
valve and which is arranged independently of the outlet valve and
which is not operatively connected thereto. The closing device is
in particular arranged adjacent to the outlet valve at the start,
pointing toward the compression chamber, of the outlet line. A risk
of a backflow of pressurized, compressed gas from the outlet line
back into the compression chamber exists in particular during a
separation of the piston compressor from the drive device, and in
particular in the case of a charged outlet line. Therefore, the
outlet line can be closed off with respect to the compression
chamber by means of the closing device in particular during the
separation of the piston compressor from the drive device. Thus,
the possibility of pressurized, compressed gas passing out of the
outlet line back into the compression chamber, and causing a
pressure increase there with the consequences described in the
introduction, in particular owing to an incompletely closed outlet
valve, during a separation of the piston compressor from the drive
device is prevented.
[0012] In one embodiment of the piston compressor, the closing
device closes the outlet line in a manner dependent on the pressure
difference prevailing at the two sides of the closing device. Here,
the closing device is designed so as to close when the pressure in
the outlet line downstream of the closing device in the flow
direction of the gas is higher than the pressure in the outlet line
upstream of the closing device, that is to say in the direction of
the compression chamber of the piston compressor. This is the case
in particular if the outlet valve does not reliably close, such
that compressed gas can flow out of the outlet line back into the
compression chamber. Here, a pressure drop occurs on that side of
the closing device which faces toward the compression chamber,
which pressure drop then leads to the closure of the closing
device.
[0013] In one embodiment of the piston compressor, a shut-off valve
forms the closing device. Shut-off valves also switch in a manner
dependent on the pressure difference prevailing at the two sides of
the shut-off valve. In the case of shut-off valves, the closing
element is normally preloaded, such that, in the case of an
identical pressure on both sides of the valve, or up to a pressure
difference that can be compensated by the preload, the valve
remains closed. Therefore, a pressure difference between the two
sides of the valve such as prevails in particular during the
compression operation of the piston compressor is necessary to open
a shut-off valve. As soon as the piston compressor is no longer
being driven--in particular during a separation of the piston
compressor from the drive device--there is no longer an adequate
pressure difference across the shut-off valve, such that the
shut-off valve closes off the outlet line with respect to the
compression chamber. A suitable type of construction of a shut-off
valve suitable for the present purpose is a check valve.
[0014] In one embodiment of the piston compressor, a switchable
valve device forms the closing device. In this embodiment, the
switching position of the closing device is freely controllable, in
particular in a manner dependent on various parameters, for example
in a manner dependent on the switching state of the clutch between
the drive device and the piston compressor, or in a manner
dependent on the pressure difference between the pressurized gas
system and the compression chamber.
[0015] In one embodiment of said piston compressor, the switchable
closing device is designed such that it is switchable into a closed
position simultaneously with the opening of the clutch. Switching
of the closing device into a closed position simultaneously with
the opening of the clutch offers the advantage that the outlet line
is always closed off with respect to the compression chamber as
soon as the piston compressor is not being driven. In this way, the
risk of an undetected leak of compressed gas back into the
compression chamber when the piston compressor is not being driven,
with the adverse effects described above, can be prevented, because
in this embodiment the outlet line is closed off when the clutch is
open, irrespective of a leak of the outlet valve.
[0016] In one embodiment of said piston compressor, a 2/2-way valve
forms the switchable valve device. Such a valve constitutes an
expedient and reliable embodiment of a switchable closing
device.
[0017] One embodiment of the piston compressor has a control device
which has a signal connection both to the clutch and to the
switchable valve device. Such a control device may be formed by the
control device of the pressurized gas system, which jointly
performs the control of the switchable valve device. It is however
alternatively also possible for the piston compressor to have, for
this purpose, a control device which is separate from the control
device of the pressurized gas system and which serves for switching
the closing device.
[0018] To achieve the object, a method for operating a piston
compressor for compressing a gas is also provided. Here, the piston
compressor is optionally separable from a drive device by way of a
clutch, and has an inlet valve, which is arranged between an inlet
line for gas for compression and a compression chamber of the
piston compressor, and has an outlet valve, which is arranged
between the compression chamber of the piston compressor and an
outlet line for compressed gas. Furthermore, the piston compressor
has a separate switchable closing device which is arranged
downstream of the outlet valve in a flow direction of the gas and
by which the outlet line can be closed off with respect to the
compression chamber during the time in which the piston compressor
is separated from the drive device, and a control device, which has
a signal connection both to the clutch and to the switchable valve
device. In the method for operating the piston compressor, the
control device switches the switchable valve device into a closed
position when the clutch between the piston compressor and the
drive device is open.
[0019] By virtue of the fact that the closing device is switched
into a closed position when the clutch between the piston
compressor and the drive device is open, the outlet line is always
closed off with respect to the compression chamber when the piston
compressor is not being driven. In this way, even in the case of an
outlet valve which is not reliably closed, no compressed gas can
pass back into the compression chamber, and give rise to the
adverse effects described above, when the piston compressor is not
being driven.
[0020] In one embodiment of the method for operating a piston
compressor, the control device switches the switchable valve device
into an open position when the clutch between the piston compressor
and the drive device is in a closed state. By means of this method
step, it is achieved that the outlet line is always open with
respect to the compression chamber of the piston compressor as soon
as the piston compressor is being driven, in order to prevent the
build-up of a back pressure at the outlet relative to the
compression chamber, which back pressure could have an adverse
effect on the compression power of the piston compressor or even
lead to damage to the piston compressor and/or to the clutch.
[0021] In one embodiment of the piston compressor that is operated
with the proposed method, the closing device is designed such that
it is switchable into a closed position simultaneously with the
opening of the clutch. The switchable closing device may in this
case be formed for example by a 2/2-way valve.
[0022] Other objects, advantages and novel features of the present
invention will become apparent from the following detailed
description of one or more preferred embodiments when considered in
conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] FIG. 1 is a schematic illustration of an exemplary piston
compressor of the prior art.
[0024] FIG. 2 is an illustration of an exemplary outlet valve as it
is used in piston compressors in the prior art.
[0025] FIG. 3 is a schematic illustration of a first exemplary
embodiment of a piston compressor according to the invention, in
which a shut-off valve forms the closing device.
[0026] FIG. 4 is a schematic illustration of a second exemplary
embodiment of a piston compressor according to the invention, in
which a switchable valve device forms the closing device.
DETAILED DESCRIPTION OF THE DRAWINGS
[0027] FIG. 1 is a schematic illustration of an exemplary piston
compressor 10 such as is known in the prior art. The crankshaft 11
of the piston compressor 10 is connected via a clutch 3 to a drive
device (not illustrated, in this case an internal combustion
engine) and is selectively separable from said drive device by way
of the clutch 3. When the clutch 3 is open, it is thus the case
that no torque is transmitted to the crankshaft 11 of the piston
compressor 10, such that the crankshaft 11 is stationary during the
separation of the piston compressor 10 from the drive device.
[0028] The crankshaft 11 is connected to a connecting rod 12 which
is mounted eccentrically on said crankshaft, on which connecting
rod there is mounted a piston 13. The piston 13 is mounted in
axially movable fashion in a cylinder 14 of the piston compressor
10. The crank drive 15, which has at least one crankshaft 11, a
connecting rod 12 and a piston 13, is arranged in a crankcase 16,
which is fixedly connected to the cylinder 14. By means of a
rotational movement of the crankshaft 11, the piston 13 is moved by
the connecting rod 12 in the cylinder 14 so as to perform a
reciprocating movement.
[0029] Above the piston 13, the cylinder 14 is closed off by a
valve plate 20. Thus, the cylinder 14, the piston 13 and the valve
plate 20 define the compression chamber 17 in the cylinder 14. On
the valve plate 20, there is arranged an inlet valve 21 which is
arranged between an inlet line 22 and the compression chamber 17.
The inlet line 22 is part of an inlet system 23 which draws fresh
air from the surroundings through a filter (not illustrated) and
supplies said fresh air via the inlet line 22 through the cylinder
head (not illustrated) to the compression chamber 17. The cylinder
head is arranged above the valve plate 20 and has a cylinder head
volume 24 which is connected via the inlet valve 21 to the
compression chamber 17. Here, the inlet valve 21 is designed as a
shut-off valve which allows fresh air to be drawn into the
compression chamber 17 but prevents a backflow of the air that has
been drawn into the compression chamber 17 via the inlet line
22.
[0030] Also arranged on the valve plate 20 is an outlet valve 26,
which is arranged between the compression chamber 17 and an outlet
line 27. Via the outlet line 27, compressed gas, in this case air,
is supplied to a compressed-air accumulator (not illustrated here).
Here, the outlet valve 26, which is likewise designed as a shut-off
valve, prevents a backflow of compressed air from the outlet line
27 into the compression chamber 17.
[0031] FIG. 2 is an illustration of an exemplary outlet valve 26
such as is commonly used in piston compressors 10 in the prior art.
The outlet valve 26 is arranged on the valve plate 20 of the piston
compressor 10 above the compression chamber 17. The valve plate 20
has an outlet opening 28 which connects the compression chamber 17
to a cylinder head volume 27a arranged in the valve plate 20 and
cylinder head of the piston compressor 10, which cylinder head
volume is connected to the outlet line 27.
[0032] The outlet valve 26 has, as a valve body, a valve tongue 26a
which, above a predetermined pressure difference between the
compression chamber 17 and the outlet line 27, lifts off from the
valve seat 26b and permits a throughflow of air from the
compression chamber 17 into the outlet line 27. The outlet valve 26
furthermore has an abutment element 26c which is arranged above the
outlet opening 28 and against which the valve tongue 26a bears in
the open state. As soon as the valve tongue 26a lifts off from the
valve seat 26b, the pressurized air can flow from the compression
chamber 17 through the lateral open regions past the valve tongue
26a and the abutment element 26c into the outlet line 27.
[0033] If contaminants from the compression chamber 17 or from the
cylinder head volume 27a, which contaminants detach for example
from coatings that are formed by residues in the throughflowing air
from the hot top side of the piston 13, from the valve plate 20 or
from the cylinder head volume 27a, pass between the valve tongue
26a and the valve seat 26b, there is the risk that the outlet valve
26 no longer completely closes. In this case, compressed air can
flow from the outlet line 27 back into the compression chamber 17
as soon as the pressure in the compression chamber 17 is lower than
the pressure in the outlet line 27. In the case of a 12.5 bar
compressed-air system of a commercial vehicle, the compression
chamber 17 of the piston compressor 10 may for example be charged
with a pressure of up to 6 bar by the air flowing back into it. If
the piston compressor 10 is then connected to the drive device
again, the piston compressor 10 generates an internal pressure of
up to 60 bar during the first stroke. If the compression chamber 17
withstands this enormous internal pressure, the torque that is
generated here at the crankshaft 11 is normally far too high for
the clutch 3, such that the latter slips, overheats, and is subject
to excessively rapid wear.
[0034] FIG. 3 is a schematic illustration of a first exemplary
embodiment of a piston compressor 10 according to the invention.
The construction of the piston compressor 10 in FIG. 3 corresponds
substantially to the construction of the piston compressor 10
illustrated in FIG. 1 and described with regard thereto, such that
identical elements of the piston compressors 10 are denoted by the
same reference designations. Below, only the differences between
the piston compressor 10 from FIG. 3 and the piston compressor 10
from FIG. 1 will be discussed.
[0035] The piston compressor 10 illustrated in FIG. 3 has a closing
device in the form of a shut-off valve, which is arranged
separately downstream of the outlet valve 26 in the flow direction.
The shut-off valve is designed as a check valve 31 with preloaded
valve body. This check valve 31 opens when the pressure of the air
which is discharged by the piston compressor 10, and which flows
out of the compression chamber 17 through the outlet valve 26, is
higher, by a magnitude, than the pressure of the air that is
situated in the outlet line 27. The magnitude of the pressure
difference is at least so great that the preload of the check valve
31 is overcome, in order that the check valve 31 opens.
[0036] While the piston compressor 10 is at a standstill, no
compressed air is situated in the compression chamber 17. Even if
the outlet valve 26 does not reliably close, no compressed air can
flow from the pressurized outlet line 27 back into the compression
chamber 17, because the outlet line is closed off with respect to
the compression chamber 17 by the check valve 31. During
compression operation of the piston compressor 10, compressed air,
which is at a higher pressure than the compressed air in the outlet
line 27, is conveyed through the outlet valve 26. Owing to the
pressure difference between the air discharged from the compression
chamber 17 and the pressure in the outlet line 27, the check valve
31 opens, and the compressed air is supplied to the outlet line 27
and thus to the compressed-air system.
[0037] FIG. 4 is a schematic illustration of a second exemplary
embodiment of a piston compressor 10 according to the invention.
The construction of the piston compressor 10 in FIG. 4 also
substantially corresponds to the construction of the piston
compressor 10 illustrated in FIG. 1 and described with regard
thereto, such that identical elements of the piston compressors 10
are denoted by the same reference designations. Only the
differences between the piston compressor 10 from FIG. 4 and the
piston compressor 10 from FIG. 1 will be discussed below.
[0038] The piston compressor 10 illustrated in FIG. 4 has a closing
device in the form of a switchable valve device 32 which is
arranged separately downstream of the outlet valve 26 in the flow
direction. The switchable valve device 32 is, in the exemplary
embodiment, designed as a 2/2-way valve, which is switchable from a
closed position into the illustrated open position. The switchable
valve device 32 is connected via a control line 32a to a control
device 33, which opens and closes the switchable valve device 32 by
means of switching signals transmitted via the control line 32a. In
the exemplary embodiment, the control device 33 is furthermore
connected via a control line 3a to the clutch 3, wherein signals
regarding the switching position of the clutch 3 are transmitted by
the control line 3a to the control device 33. The control device 33
is optionally connected via a control line 33a to the controller of
the compressed-air system.
[0039] While the piston compressor 10 is at a standstill--the
clutch between the drive device and the piston compressor 10 is
open--the switchable valve device 32 is switched into the closed
position. Even if the outlet valve 26 does not reliably close, no
compressed air can flow from the pressurized outlet line 27 back
into the compression chamber 17, because the outlet line 27 is
closed off with respect to the compression chamber 17 when the
switchable valve device 32 is in the closed position. Upon the
closure of the clutch 3 at the start of compression operation of
the piston compressor 10, the switchable valve device 32 is
switched into the open position shown in FIG. 4. In this way,
compressed air which is at a higher pressure than the compressed
air in the outlet line 27 can be conveyed through the outlet valve
26, and through the switchable valve device 32 which is situated in
the open position, into the outlet line 27, and supplied to the
compressed-air system. Optionally, in a variant in which the
control device 33 is connected to the controller of the
compressed-air system, the opening of the clutch 3 may take place
simultaneously with the switching of the switchable valve device 32
into the closed position, and the closing of the clutch 3 may take
place simultaneously with the switching of the switchable valve
device 32 into the open position.
LIST OF REFERENCE DESIGNATIONS
[0040] 3 Clutch [0041] 3a Control line [0042] 10 Piston compressor
[0043] 11 Crankshaft [0044] 12 Connecting rod [0045] 13 Piston
[0046] 14 Cylinder [0047] 15 Crank drive [0048] 16 Crankcase [0049]
17 Compression chamber [0050] 20 Valve plate [0051] 21 Inlet valve
[0052] 22 Inlet line [0053] 23 Inlet system [0054] 24 Cylinder head
volume (inlet) [0055] 26 Outlet valve [0056] 26a Valve tongue
[0057] 26b Valve seat [0058] 26c Abutment element [0059] 27 Outlet
line [0060] 28 Outlet opening [0061] 31 Shut-off valve [0062] 32
Switchable valve device [0063] 32a Control line [0064] 33 Control
device [0065] 33a Control line
[0066] The foregoing disclosure has been set forth merely to
illustrate the invention and is not intended to be limiting. Since
modifications of the disclosed embodiments incorporating the spirit
and substance of the invention may occur to persons skilled in the
art, the invention should be construed to include everything within
the scope of the appended claims and equivalents thereof.
* * * * *