US20060120898A1 - Starting method for a piston compressor and piston compressor - Google Patents
Starting method for a piston compressor and piston compressor Download PDFInfo
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- US20060120898A1 US20060120898A1 US11/289,144 US28914405A US2006120898A1 US 20060120898 A1 US20060120898 A1 US 20060120898A1 US 28914405 A US28914405 A US 28914405A US 2006120898 A1 US2006120898 A1 US 2006120898A1
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- Prior art keywords
- piston
- resetting
- starting
- drive moment
- piston compressor
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B49/00—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00
- F04B49/02—Stopping, starting, unloading or idling control
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B2201/00—Pump parameters
- F04B2201/02—Piston parameters
- F04B2201/0201—Position of the piston
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B2201/00—Pump parameters
- F04B2201/12—Parameters of driving or driven means
- F04B2201/1208—Angular position of the shaft
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B2203/00—Motor parameters
- F04B2203/02—Motor parameters of rotating electric motors
- F04B2203/0207—Torque
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B2203/00—Motor parameters
- F04B2203/02—Motor parameters of rotating electric motors
- F04B2203/0209—Rotational speed
Definitions
- the invention relates to a method for starting a piston compressor.
- the invention relates, furthermore, to a piston compressor operating according to the method.
- a piston compressor conventionally has at least one piston which can be moved in a pressure cylinder by a motor in such a way that the volume of a compression space formed between the pressure cylinder and the piston is periodically expanded and compressed in the course of the piston movement.
- a compressible fluid in particular a refrigerant such as R600a, for example, is sucked into the compression space through an inlet valve provided in the pressure cylinder.
- the sucked-in fluid is compressed and expelled under increased pressure through an outlet valve of the pressure cylinder.
- the piston position which identifies the transition from a compression phase into a subsequent expansion phase is designated below as the compression point.
- that piston position which identifies the transition between an expansion phase and a subsequent compression phase is designated as the expansion point.
- the designation “piston compressor” relates both to a reciprocating-piston compressor and to a rotary-piston or rolling-piston compressor.
- a reciprocating-piston compressor is concerned, a piston is movable linearly in the pressure cylinder.
- the piston of such a reciprocating-piston compressor is conventionally driven by a rotating eccentric.
- a rotary-piston cylinder is concerned, the piston, by contrast, is driven in rotation directly via a drive shaft and rotates with respect to the pressure cylinder.
- the rotary position of the drive shaft or of the eccentric is adopted below as a measure of the piston position, so that reference to a specific piston position of a reciprocating-piston compressor is also in the form of a given angle value.
- the sequence of an expansion phase and of a subsequent compression phase, to which, as a rule, a full rotation of the drive shaft or of the eccentric through 360° corresponds, is designated as the work cycle of the piston compressor.
- a load moment occurs which fluctuates periodically with the work cycle and which, as a rule, passes through a pronounced maximum (designated below as the load peak) in the course of the compression phase. It is customary to configure an electronically regulated piston compressor in such a way that the maximum drive moment of the motor undershoots the maximum value of the load moment occurring during the load peak.
- the load peak is overcome by the inertia of the piston compressor, that is to say by the kinetic energy stored in a flywheel mass.
- the piston position is designated below as the steady-state point.
- a method for starting a piston compressor which includes during a resetting phase, driving a piston of the piston compressor in a direction of a compression point of a piston position by applying a resetting drive moment. Maintaining the resetting drive moment until the piston reaches a starting position by overstepping a steady-state point as a result of displacement of fluid out of a compression space, formed between the piston and a corresponding pressure cylinder, through at least one leakage point.
- an acceleration phase accelerating the piston out of the starting position into an operational direction of rotation with a starting drive moment.
- a resetting phase for driving the piston of the piston compressor in the direction of a compression point of the piston position by the application of a resetting drive moment, and for maintaining the resetting drive moment until, by overshooting a steady-state point, the piston has reached a starting position.
- an acceleration phase following the reaching of the starting position the piston is then accelerated out of the starting position in an operational direction of rotation by a starting drive moment.
- the outlet point which is used is, in particular, the piston/cylinder play always present as a consequence of construction in a piston compressor.
- the resetting drive moment is preferably directed opposite to the operational direction of rotation, so that, during the resetting phase, the piston compressor is rotated backwards opposite to the operational direction of rotation.
- This is expedient particularly when, as a result of the type of construction of the piston compressor, a lower load moment and/or a higher leakage rate occur(s) during backward rotation than during corresponding forward rotation.
- the output or leakage rate and the profile of the load moment behaves, as a rule, symmetrically with respect to a reversal in the direction of rotation.
- the piston may also be driven equivalently in the operational direction of rotation.
- the starting position is preferably selected such that it lies in the vicinity of the compression point or slightly precedes the latter, as seen in the operational direction of rotation. Expediently, the starting position lies, in particular, in an angular range of +/ ⁇ 30° about the compression point.
- the piston compressor contains a piston movable in a pressure cylinder by a drive system.
- the drive system contains an electric motor active on the piston via a drive shaft and an electronic control unit activating the motor.
- the control unit is in this case configured for activating the motor according to the method described above.
- the control unit is in this case configured, in particular, for activating the motor during the resetting phase in such a way that the piston is driven in the direction of the compression point under the action of the resetting drive moment, and for maintaining the resetting drive moment until the piston has reached a starting position.
- the control unit is configured, furthermore, to activate the motor during the acceleration phase in such a way that the piston is accelerated out of the starting position into the operational direction of rotation under the action of the starting drive moment.
- FIGS. 1 to 4 are diagrammatic, sectional views of a piston compressor in four successive piston positions during the starting operation of the piston compressor according to the invention
- FIG. 5 is a graph of a characteristic profile of a load moment occurring during the operation of the piston compressor according to FIG. 1 , as a function of the piston position;
- FIG. 6 is a graph according to FIG. 5 showing the profile of the load moment during the starting operation.
- FIGS. 1-4 there is shown a piston compressor 1 illustrated diagrammatically as a reciprocating-piston compressor.
- the piston compressor 1 contains a piston 2 which is displaceable linearly (in a vertical direction according to FIG. 1 ) in a pressure cylinder 3 .
- an electric motor 4 is provided, which, in particular, is configured as a permanent-magnet synchronous motor and is activated by an electronic control unit 5 .
- the motor 4 acts via a drive shaft 6 , merely indicated, on a drive eccentric 7 which, in turn, is connected in an articulated manner to the piston 2 via a connecting rod 8 , so that the rotational movement of the drive eccentric 7 is converted into a linear oscillating movement of the piston 2 in a known way.
- the pressure cylinder 3 and the piston 2 delimit the compression space 9 , into which an inlet 11 and an outlet 12 for a fluid F to be compressed issue on a cylinder bottom 10 , facing away from the piston 2 , of the pressure cylinder 3 .
- the fluid F is preferably a refrigerant, for example R600a.
- an inlet valve 13 and outlet valve 14 are provided, which respectively shut off in a fluid-tight manner or release the inlet 11 and the outlet 12 , depending on the valve position.
- Each valve 13 or 14 is configured as a flap which is prestressed into a closed position of rest by an elastic force, in particular a spring, or due to the elastic configuration of the flap itself.
- Each valve 13 or 14 opens and closes automatically, in the manner of a non-return valve, under the action of a corresponding pressure gradient of the fluid F.
- the inlet valve 13 in this case opens when a sufficient under pressure prevails in the compression space 9 with respect to the inlet 11 .
- the outlet valve 14 opens when a sufficient over pressure prevails in the compression space 9 with respect to the outlet 12 .
- the volume of the compression space 9 varies as a function of piston position S.
- the rotary or annular position of the drive shaft 6 and of the drive eccentric 7 connected fixedly in terms of rotation to the latter is adopted as a measure of the piston position S.
- a change in the piston position S from 0° to 180° corresponds to an expansion phase E ( FIG.
- a full rotation of the drive eccentric 7 that is to say a change in the piston position S from 0° to 360°, is designated as the work cycle of the piston compressor 1 .
- the work cycle thus contains the expansion phase E and the subsequent compression phase K.
- the load moment L varies periodically as a function of the piston position S.
- the amount of the load moment L occurring during the expansion phase E is small, whereas, in the course of the compression phase K, the load moment L passes through a pronounced maximum which is designated below as the load peak P.
- a maximum load moment L max is reached in the region of the load peak P, for example, in a piston position S ⁇ 270°.
- the motor 4 is configured in such a way that a maximum drive moment A max capable of being exerted on the drive eccentric 7 is lower than the maximum load moment L max . Consequently, there is a piston position S, in which the load moment L just overshoots the maximum drive moment A max , so that the motor power is no longer sufficient for further compression.
- the steady-state point S b occurs in the vicinity of the load peak P, that is to say, when the piston 2 is driven in the operational direction B, in a piston position S which slightly undershoots 270°.
- the starting operation of the piston compressor 1 is accordingly divided into a resetting phase 15 ( FIG. 6 ) and a subsequent acceleration phase 16 ( FIG. 6 ).
- the piston 2 is rotated backwards out of the initial piston position S I , opposite to the operational direction of rotation B, with a low drive moment, until, with regard to the piston position S, a starting position S IV ( FIG. 4 ) is reached.
- the piston compressor 1 in this case passes through the piston positions S II and S III illustrated in FIGS. 2 and 3 .
- the starting position S IV is selected in the vicinity of the compression point S k and in this case, in particular, between the steady-state points S b and S′ b , so that, during the resetting phase 15 , the steady-state point S′ b has to be overcome when the piston 2 is rotated backwards. Likewise, if the piston 2 were to be moved into the starting position S IV by forward rotation, the steady-state point S b would have to be overcome.
- the steady-state point S′ b is overcome in that, during the resetting phase 15 , the motor 4 exerts a resetting drive moment A R which is also maintained precisely when the steady-state point S′ b is reached or overshot.
- This is implemented in technical terms in that the stator field of the motor 4 is rotated backwards at a low angular speed for a predetermined time span.
- output points of the compression space 9 which, as a consequence of construction, are formed, in particular, by the piston/cylinder play always present to some extent, are utilized in a controlled way.
- fluid F FIG. 3
- the volume of the compression space 9 is further reduced and the piston position S thereby approaches the compression point S k beyond the steady-state point S′ b .
- the load peak P′ is virtually “tunneled through” in this way.
- a leakage point which, if appropriate, connects the compression space 9 to the inlet 11 may also be utilized additionally or alternatively to the leakage or output points 17 formed by the piston/cylinder play. Additionally or alternatively to leakage points 17 obtained as a consequence of construction, an artificial leakage point, for example in the form of a thin bypass line circumventing the inlet valve 13 , may also be provided. This is expedient particularly when an escape of the fluid F into the environment is to be avoided.
- the exact site of the starting position S IV depends slightly on the initial piston position S I .
- Motor activation during the resetting phase 15 is in this case configured in such a way that the starting position S IV always lies in an angular range of +/ ⁇ 30° about the compression point S k and, in an initial piston position S I of approximately 180°, coincides substantially with the compression point S k .
- the piston position S passes through an acceleration range 18 of more than 240°, in the course of which no increased load moment L occurs, with the result that the piston compressor 1 can absorb sufficient momentum to overcome the load peak P.
- the long acceleration range 18 thus makes it possible for the motor 4 to be configured with a particularly low maximum drive moment A max , without the starting behavior of the piston compressor 1 being impaired.
- the resetting phase 15 and the acceleration phase 16 may be executed directly one after the other in time. However, the resetting phase 15 and the acceleration phase 16 may also be executed separately from one another in time. In particular, there is optionally provision for carrying out the resetting phase 15 at the end of an operating phase of the piston compressor 1 , so that, during a subsequent operating phase, the piston compressor 1 is already in the starting position S IV from the outset and can be started immediately by the execution of the acceleration phase 16 . Alternatively to this, there is optionally provision for the method described above to be carried out only when a previously conducted attempt at immediate starting has failed because of an unfavorable initial piston position S I .
- a resetting drive moment A R acting in the operational direction of rotation B may also be exerted.
- the starting method described can also be applied equivalently to a rotary-piston compressor.
- the method described can also be used equivalently in a piston compressor with a different type of electronically regulated motor, in particular a brushless direct-current motor (BLDC), an asynchronous motor, a reluctance motor, etc.
- BLDC brushless direct-current motor
- asynchronous motor a reluctance motor, etc.
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Abstract
In an effective method for starting a piston compressor which is easy to implement, and a piston compressor suitable for carrying out the method, there is provision, in a resetting phase, for driving a piston of the piston compressor in the direction of a compression point of the piston position by the application of a resetting drive moment. The resetting drive moment being maintained until the piston has reached a starting position by overstepping a steady-state point as a result of displacement of fluid out of the compression space, formed between the piston and a corresponding pressure cylinder, through at least one leakage point. In a subsequent acceleration phase, the piston is then accelerated out of the starting position into an operational direction of rotation with a starting drive moment.
Description
- The invention relates to a method for starting a piston compressor. The invention relates, furthermore, to a piston compressor operating according to the method.
- A piston compressor conventionally has at least one piston which can be moved in a pressure cylinder by a motor in such a way that the volume of a compression space formed between the pressure cylinder and the piston is periodically expanded and compressed in the course of the piston movement. During the expansion phase, in this case a compressible fluid, in particular a refrigerant such as R600a, for example, is sucked into the compression space through an inlet valve provided in the pressure cylinder. During the subsequent compression phase, the sucked-in fluid is compressed and expelled under increased pressure through an outlet valve of the pressure cylinder. The piston position which identifies the transition from a compression phase into a subsequent expansion phase is designated below as the compression point. In a similar way to this, that piston position which identifies the transition between an expansion phase and a subsequent compression phase is designated as the expansion point.
- The designation “piston compressor” relates both to a reciprocating-piston compressor and to a rotary-piston or rolling-piston compressor. Where a reciprocating-piston compressor is concerned, a piston is movable linearly in the pressure cylinder. The piston of such a reciprocating-piston compressor is conventionally driven by a rotating eccentric. Where a rotary-piston cylinder is concerned, the piston, by contrast, is driven in rotation directly via a drive shaft and rotates with respect to the pressure cylinder. Without restriction to one of these two forms of construction, the rotary position of the drive shaft or of the eccentric is adopted below as a measure of the piston position, so that reference to a specific piston position of a reciprocating-piston compressor is also in the form of a given angle value. The sequence of an expansion phase and of a subsequent compression phase, to which, as a rule, a full rotation of the drive shaft or of the eccentric through 360° corresponds, is designated as the work cycle of the piston compressor.
- When a piston compressor is in operation, a load moment occurs which fluctuates periodically with the work cycle and which, as a rule, passes through a pronounced maximum (designated below as the load peak) in the course of the compression phase. It is customary to configure an electronically regulated piston compressor in such a way that the maximum drive moment of the motor undershoots the maximum value of the load moment occurring during the load peak. In operation, the load peak is overcome by the inertia of the piston compressor, that is to say by the kinetic energy stored in a flywheel mass.
- When a piston compressor is started, the momentum required for this purpose is not available, so that a usual piston compressor often cannot be started by its inherent force, or at least not from every piston position. In order to increase the momentum travel and thus make self-starting easier, the piston of the piston compressor is sometimes rotated backwards, opposite to an operational direction of rotation, before the actual starting operation. In a conventional piston compressor, the backward rotation of the piston is terminated at the latest in a piston position in which the maximum drive torque of the motor corresponds to the load moment opposing a further compression.
- It is accordingly an object of the invention to provide a starting method for a piston compressor and a piston compressor which overcomes the above-mentioned disadvantages of the prior art devices and methods of this general type, by which an improved starting behavior is achieved in a simple way in a piston compressor. The piston position is designated below as the steady-state point.
- With the foregoing and other objects in view there is provided, in accordance with the invention, a method for starting a piston compressor, which includes during a resetting phase, driving a piston of the piston compressor in a direction of a compression point of a piston position by applying a resetting drive moment. Maintaining the resetting drive moment until the piston reaches a starting position by overstepping a steady-state point as a result of displacement of fluid out of a compression space, formed between the piston and a corresponding pressure cylinder, through at least one leakage point. During an acceleration phase, accelerating the piston out of the starting position into an operational direction of rotation with a starting drive moment.
- Accordingly, there is provision, first, in a resetting phase, for driving the piston of the piston compressor in the direction of a compression point of the piston position by the application of a resetting drive moment, and for maintaining the resetting drive moment until, by overshooting a steady-state point, the piston has reached a starting position. In this case, use is made in a controlled way of at least one leakage point (outlet) of the piston compressor, through which the fluid compressed in the course of the resetting phase escapes from the compression space, so that the piston position successively approaches the starting position beyond the steady-state point. In an acceleration phase following the reaching of the starting position, the piston is then accelerated out of the starting position in an operational direction of rotation by a starting drive moment. The outlet point which is used is, in particular, the piston/cylinder play always present as a consequence of construction in a piston compressor.
- By the method described above, a particularly long acceleration travel for absorbing the kinetic energy required for overcoming the load peak is achieved in a simple way in a piston compressor. The drive system of the piston compressor operating by the method according to the invention can thereby be configured for a comparatively low maximum drive torque. As a result, production costs are saved to a decisive extent.
- The resetting drive moment is preferably directed opposite to the operational direction of rotation, so that, during the resetting phase, the piston compressor is rotated backwards opposite to the operational direction of rotation. This is expedient particularly when, as a result of the type of construction of the piston compressor, a lower load moment and/or a higher leakage rate occur(s) during backward rotation than during corresponding forward rotation. Particularly where a reciprocating-piston compressor is concerned, the output or leakage rate and the profile of the load moment behaves, as a rule, symmetrically with respect to a reversal in the direction of rotation. In this case, during the resetting phase, the piston may also be driven equivalently in the operational direction of rotation.
- In order to achieve as long an acceleration travel as possible during the acceleration phase, the starting position is preferably selected such that it lies in the vicinity of the compression point or slightly precedes the latter, as seen in the operational direction of rotation. Expediently, the starting position lies, in particular, in an angular range of +/−30° about the compression point.
- Accordingly, the piston compressor contains a piston movable in a pressure cylinder by a drive system. The drive system contains an electric motor active on the piston via a drive shaft and an electronic control unit activating the motor. The control unit is in this case configured for activating the motor according to the method described above. The control unit is in this case configured, in particular, for activating the motor during the resetting phase in such a way that the piston is driven in the direction of the compression point under the action of the resetting drive moment, and for maintaining the resetting drive moment until the piston has reached a starting position. The control unit is configured, furthermore, to activate the motor during the acceleration phase in such a way that the piston is accelerated out of the starting position into the operational direction of rotation under the action of the starting drive moment.
- Other features which are considered as characteristic for the invention are set forth in the appended claims.
- Although the invention is illustrated and described herein as embodied in a starting method for a piston compressor and a piston compressor, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
- The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.
- FIGS. 1 to 4 are diagrammatic, sectional views of a piston compressor in four successive piston positions during the starting operation of the piston compressor according to the invention;
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FIG. 5 is a graph of a characteristic profile of a load moment occurring during the operation of the piston compressor according toFIG. 1 , as a function of the piston position; and -
FIG. 6 is a graph according toFIG. 5 showing the profile of the load moment during the starting operation. - In all the figures of the drawing, sub-features and integral parts that correspond to one another bear the same reference symbol in each case. Referring now to the figures of the drawing in detail and first, particularly, to
FIGS. 1-4 thereof, there is shown apiston compressor 1 illustrated diagrammatically as a reciprocating-piston compressor. Thepiston compressor 1 contains apiston 2 which is displaceable linearly (in a vertical direction according toFIG. 1 ) in apressure cylinder 3. For driving thepiston 2, anelectric motor 4 is provided, which, in particular, is configured as a permanent-magnet synchronous motor and is activated by an electronic control unit 5. Themotor 4 acts via adrive shaft 6, merely indicated, on a drive eccentric 7 which, in turn, is connected in an articulated manner to thepiston 2 via a connectingrod 8, so that the rotational movement of the drive eccentric 7 is converted into a linear oscillating movement of thepiston 2 in a known way. - The
pressure cylinder 3 and thepiston 2 delimit thecompression space 9, into which aninlet 11 and anoutlet 12 for a fluid F to be compressed issue on acylinder bottom 10, facing away from thepiston 2, of thepressure cylinder 3. The fluid F is preferably a refrigerant, for example R600a. - At the respective issue of the
inlet 11 andoutlet 12 into thecompression space 9, aninlet valve 13 andoutlet valve 14 are provided, which respectively shut off in a fluid-tight manner or release theinlet 11 and theoutlet 12, depending on the valve position. Eachvalve valve inlet valve 13 in this case opens when a sufficient under pressure prevails in thecompression space 9 with respect to theinlet 11. Similarly, theoutlet valve 14 opens when a sufficient over pressure prevails in thecompression space 9 with respect to theoutlet 12. - The volume of the
compression space 9 varies as a function of piston position S. In this case, the rotary or annular position of thedrive shaft 6 and of the drive eccentric 7 connected fixedly in terms of rotation to the latter is adopted as a measure of the piston position S. In a piston position S=0°, thepiston 2 is moved into thepressure cylinder 3 to a maximum extent, and the volume of thepressure space 9 is thus minimized. In a piston position S=180°, thepiston 2 is correspondingly drawn out of thepressure cylinder 3 to a maximum extent, and the volume of thecompression space 9 is thus maximized. Given rotation of the drive eccentric 7 in an operational direction of rotation B indicated inFIG. 1 , a change in the piston position S from 0° to 180° corresponds to an expansion phase E (FIG. 5 ), in the course of which thecompression space 9 expands, and therefore fluid is sucked in from theinlet 11. A change in the piston position S from 180° to 360°=0° corresponds to a compression phase K (FIG. 5 ), during which the fluid F contained in thecompression space 9 is compressed and is expelled through theoutlet 12. The commencement of the expansion phase E corresponding to a piston position S=0° is designated as the compression point Sk, and the commencement of the compression phase K corresponding to a piston position S=180° is designated as the expansion point Se. A full rotation of the drive eccentric 7, that is to say a change in the piston position S from 0° to 360°, is designated as the work cycle of thepiston compressor 1. The work cycle thus contains the expansion phase E and the subsequent compression phase K. - During the operation of the
piston compressor 1, there arises—essentially due to the variable fluid pressure in thecompression space 9—a load torque (designated below in brief as the load moment L) which is exerted on the drive eccentric 7 by thepiston 2 and which counteracts a drive torque (designated below in brief as the drive moment A) which is exerted on the drive eccentric 7 by themotor 4. - As illustrated by way of example in
FIG. 5 , the load moment L varies periodically as a function of the piston position S. Under usual operating conditions, the amount of the load moment L occurring during the expansion phase E is small, whereas, in the course of the compression phase K, the load moment L passes through a pronounced maximum which is designated below as the load peak P. A maximum load moment Lmax is reached in the region of the load peak P, for example, in a piston position S≈270°. - The
motor 4 is configured in such a way that a maximum drive moment Amax capable of being exerted on the drive eccentric 7 is lower than the maximum load moment Lmax. Consequently, there is a piston position S, in which the load moment L just overshoots the maximum drive moment Amax, so that the motor power is no longer sufficient for further compression. The steady-state point Sb, as it may be referred to, occurs in the vicinity of the load peak P, that is to say, when thepiston 2 is driven in the operational direction B, in a piston position S which slightly undershoots 270°. - When the
piston 2 is driven opposite to the operational direction of rotation B, a load moment L′ (indicated inFIG. 3 as a dotted line) substantially mirror-symmetric with respect to the compression point Sk and having an associated load peak P′ occurs in the piston compressor. During backward rotation, a corresponding steady-state point S′b is reached in a piston position S slightly overshooting 90°. - When the
piston compressor 1 is in operation, the steady-state point Sb and consequently the load peak P are overcome by the kinetic energy of thepiston compressor 1 being utilized. However, the kinetic energy is not yet available during the starting of thepiston compressor 1, so that thepiston compressor 1 cannot be started directly by its inherent force from an initial piston position SI illustrated by way of example inFIG. 1 . The method described in more detail below with reference to FIGS. 2 to 4 and 6 serves for improving the starting behavior of thepiston compressor 1. - The starting operation of the
piston compressor 1 is accordingly divided into a resetting phase 15 (FIG. 6 ) and a subsequent acceleration phase 16 (FIG. 6 ). During theresetting phase 15, thepiston 2 is rotated backwards out of the initial piston position SI, opposite to the operational direction of rotation B, with a low drive moment, until, with regard to the piston position S, a starting position SIV (FIG. 4 ) is reached. Thepiston compressor 1 in this case passes through the piston positions SII and SIII illustrated inFIGS. 2 and 3 . - What is characteristic of the method according to the invention is that the starting position SIV is selected in the vicinity of the compression point Sk and in this case, in particular, between the steady-state points Sb and S′b, so that, during the
resetting phase 15, the steady-state point S′b has to be overcome when thepiston 2 is rotated backwards. Likewise, if thepiston 2 were to be moved into the starting position SIV by forward rotation, the steady-state point Sb would have to be overcome. - The steady-state point S′b is overcome in that, during the
resetting phase 15, themotor 4 exerts a resetting drive moment AR which is also maintained precisely when the steady-state point S′b is reached or overshot. This is implemented in technical terms in that the stator field of themotor 4 is rotated backwards at a low angular speed for a predetermined time span. - In this case, output points of the
compression space 9, which, as a consequence of construction, are formed, in particular, by the piston/cylinder play always present to some extent, are utilized in a controlled way. With the resetting drive moment AR being maintained, fluid F (FIG. 3 ) escapes through the output points 17 to an appreciable extent, contrary to the usual operating behavior of thepiston compressor 1, so that, under stationary load conditions, the volume of thecompression space 9 is further reduced and the piston position S thereby approaches the compression point Sk beyond the steady-state point S′b. The load peak P′ is virtually “tunneled through” in this way. - Depending on the type of construction of the
piston compressor 1, a leakage point which, if appropriate, connects thecompression space 9 to theinlet 11 may also be utilized additionally or alternatively to the leakage oroutput points 17 formed by the piston/cylinder play. Additionally or alternatively toleakage points 17 obtained as a consequence of construction, an artificial leakage point, for example in the form of a thin bypass line circumventing theinlet valve 13, may also be provided. This is expedient particularly when an escape of the fluid F into the environment is to be avoided. - The exact site of the starting position SIV depends slightly on the initial piston position SI. Motor activation during the
resetting phase 15 is in this case configured in such a way that the starting position SIV always lies in an angular range of +/−30° about the compression point Sk and, in an initial piston position SI of approximately 180°, coincides substantially with the compression point Sk. It has proved expedient, for the suitable dimensioning of the resetting drive moment AR, to have a motor activation in which the stator field of themotor 4 is rotated backwards at an angular speed of between 1 and 10 revolutions per minute for a predetermined time span of between 3 and 30 seconds, in particular at approximately 4 revolutions per minute for approximately 20 seconds. - After the starting position SIV is reached, in the course of the acceleration phase 16 a starting drive moment AS is exerted on the drive eccentric 7, and therefore on the
piston 2, the starting drive moment acting in the operational direction of rotation B and corresponding in terms of its amount to the maximum drive moment Amax. - As can be seen particularly from
FIG. 6 , during theacceleration phase 16 the piston position S passes through anacceleration range 18 of more than 240°, in the course of which no increased load moment L occurs, with the result that thepiston compressor 1 can absorb sufficient momentum to overcome the load peak P. Thelong acceleration range 18 thus makes it possible for themotor 4 to be configured with a particularly low maximum drive moment Amax, without the starting behavior of thepiston compressor 1 being impaired. - The resetting
phase 15 and theacceleration phase 16 may be executed directly one after the other in time. However, the resettingphase 15 and theacceleration phase 16 may also be executed separately from one another in time. In particular, there is optionally provision for carrying out the resettingphase 15 at the end of an operating phase of thepiston compressor 1, so that, during a subsequent operating phase, thepiston compressor 1 is already in the starting position SIV from the outset and can be started immediately by the execution of theacceleration phase 16. Alternatively to this, there is optionally provision for the method described above to be carried out only when a previously conducted attempt at immediate starting has failed because of an unfavorable initial piston position SI. - Where the piston compressor illustration in FIGS. 1 to 4 is concerned, furthermore, in a variant of the starting method described, a resetting drive moment AR acting in the operational direction of rotation B may also be exerted. Furthermore, the starting method described can also be applied equivalently to a rotary-piston compressor.
- The method described can also be used equivalently in a piston compressor with a different type of electronically regulated motor, in particular a brushless direct-current motor (BLDC), an asynchronous motor, a reluctance motor, etc.
- This application also claims the priority, under 35 U.S.C. §119, of German patent application No. 10 2004 057 467.7, filed Nov. 29, 2004; the entire disclosure of the prior application is herewith incorporated by reference.
Claims (6)
1. A method for starting a piston compressor, which comprises the steps of:
during a resetting phase, driving a piston of the piston compressor in a direction of a compression point of a piston position by applying a resetting drive moment;
maintaining the resetting drive moment until the piston reaches a starting position by overstepping a steady-state point as a result of displacement of fluid out of a compression space, formed between the piston and a corresponding pressure cylinder, through at least one leakage point; and
during an acceleration phase, accelerating the piston out of the starting position into an operational direction of rotation with a starting drive moment.
2. The method according to claim 1 , which further comprises directing the resetting drive moment opposite to the operational direction of rotation.
3. The method according to claim 1 , which further comprises selecting the starting position in an angular range of the piston position of +/−30° with respect to the compression point.
4. The method according to claim 1 , which further comprises exciting a stator field of a motor driving the piston compressor at a predetermined angular speed of between 1 and 10 revolutions per minute for a predetermined time span of between 3 and 30 seconds for generating the resetting drive moment.
5. The method according to claim 1 , which further comprises setting said starting drive moment to correspond to a predetermined maximum drive moment.
6. A piston compressor, comprising:
a pressure cylinder;
a drive shaft;
a motor driving said drive shaft;
a piston being moved in said pressure cylinder by said drive shaft being driven by said motor; and
a control unit for activating said motor, said control unit being configured to:
in a resetting phase, predetermine a resetting drive moment, by which said piston being driven in a direction of a compression point of a piston position;
maintain the resetting drive moment until said piston reaches a starting position by overstepping a steady-state point as a result of displacement of fluid out of a compression space, formed between said piston and said pressure cylinder, through a leakage point; and
in an acceleration phase, predetermine a starting drive moment, by which said piston is accelerated out of the starting position into an operational direction of rotation.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE102004057467A DE102004057467B3 (en) | 2004-11-29 | 2004-11-29 | Starting process for a reciprocating compressor |
DE102004057467.7 | 2004-11-29 |
Publications (1)
Publication Number | Publication Date |
---|---|
US20060120898A1 true US20060120898A1 (en) | 2006-06-08 |
Family
ID=35953870
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US11/289,144 Abandoned US20060120898A1 (en) | 2004-11-29 | 2005-11-29 | Starting method for a piston compressor and piston compressor |
Country Status (7)
Country | Link |
---|---|
US (1) | US20060120898A1 (en) |
EP (1) | EP1662143B1 (en) |
CN (1) | CN1782387B (en) |
AT (1) | ATE434727T1 (en) |
DE (2) | DE102004057467B3 (en) |
ES (1) | ES2327133T3 (en) |
PL (1) | PL1662143T3 (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20070085501A1 (en) * | 2005-10-14 | 2007-04-19 | Samsung Electronics Co., Ltd. | Compressor and a driving method thereof |
US20080031747A1 (en) * | 2004-05-17 | 2008-02-07 | Koninklijke Philips Electronics N.V. | Reciprocating Pump With Reduced Noise Level |
US20150048109A1 (en) * | 2012-03-22 | 2015-02-19 | Wuxi Little Swan Co., Ltd. | Dosing Device Overcoming Change In Viscidity Of Detergent And Method For Controlling Same |
WO2022109700A1 (en) | 2020-11-25 | 2022-06-02 | Embraco Indústria De Compressores E Soluções Em Refrigeração Ltda. | Piston positioning processes of a reciprocating compressor |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE102012006495A1 (en) * | 2011-04-01 | 2013-01-24 | Secop Gmbh | Method for starting a pump with non-constant torque curve |
CN106089668A (en) * | 2016-08-15 | 2016-11-09 | 无锡惠山泵业有限公司 | A kind of high efficiency energy saving pump |
Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4401419A (en) * | 1979-09-21 | 1983-08-30 | Electrolux Siegen Gmbh | Motor-compressor |
US4656376A (en) * | 1985-06-15 | 1987-04-07 | Danfoss A/S | Motor-compressor unit with offset starting torque |
US4726738A (en) * | 1985-01-16 | 1988-02-23 | Hitachi, Ltd. | Motor-driven compressor provided with torque control device |
US5388967A (en) * | 1993-03-10 | 1995-02-14 | Sullair Corporation | Compressor start control and air inlet valve therefor |
US5801500A (en) * | 1995-03-18 | 1998-09-01 | Danfoss A/S | Motor/compressor combination having a control arrangement for starting the motor with asynchronous and then synchronous commutation |
US5988994A (en) * | 1997-10-21 | 1999-11-23 | Global Cooling Manufacturing Company | Angularly oscillating, variable displacement compressor |
US6648604B1 (en) * | 1998-06-05 | 2003-11-18 | Carrier Corporation | Short reverse rotation of scroll compressor at startup |
US6781342B2 (en) * | 2002-05-29 | 2004-08-24 | Bristol Compressors, Inc. | System and method for soft starting a three phase motor |
Family Cites Families (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE843135C (en) * | 1950-01-25 | 1952-07-07 | Mannesmann Fa A | Starting device for piston compressor |
DE2502158A1 (en) * | 1975-01-21 | 1976-07-22 | Stiebel Eltron Gmbh & Co Kg | Compressor for encapsulated refrigerators - fitted with pressure balancing valve operated by a control unit |
DE8702221U1 (de) * | 1987-02-13 | 1987-04-09 | Becker, Erich, 7812 Bad Krozingen | Pumpe mit vom Fördermedium gesteuerten Ventilen |
CN2143685Y (en) * | 1992-12-10 | 1993-10-13 | 郝雷 | Conveniently starting less oil low noise air pump |
US6085533A (en) * | 1999-03-15 | 2000-07-11 | Carrier Corporation | Method and apparatus for torque control to regulate power requirement at start up |
DE10023523C1 (en) * | 2000-05-13 | 2001-12-13 | Vacuubrand Gmbh & Co Kg | Run-up control for membrane and/or piston vacuum pump uses short-term reversal of pump when initial maximum torque in forwards rotation direction is not overcome |
DE10133861B4 (en) * | 2001-07-12 | 2007-06-06 | Netzsch-Mohnopumpen Gmbh | Drive system for pumps |
CN1201082C (en) * | 2001-12-18 | 2005-05-11 | 乐金电子(天津)电器有限公司 | Starting control method of variable volume compressor |
CN2606201Y (en) * | 2003-02-19 | 2004-03-10 | 吴体胜 | Compressor starter without load |
-
2004
- 2004-11-29 DE DE102004057467A patent/DE102004057467B3/en not_active Expired - Fee Related
-
2005
- 2005-10-21 CN CN2005101163647A patent/CN1782387B/en not_active Expired - Fee Related
- 2005-11-19 PL PL05025299T patent/PL1662143T3/en unknown
- 2005-11-19 EP EP05025299A patent/EP1662143B1/en not_active Not-in-force
- 2005-11-19 AT AT05025299T patent/ATE434727T1/en not_active IP Right Cessation
- 2005-11-19 DE DE502005007559T patent/DE502005007559D1/en active Active
- 2005-11-19 ES ES05025299T patent/ES2327133T3/en active Active
- 2005-11-29 US US11/289,144 patent/US20060120898A1/en not_active Abandoned
Patent Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4401419A (en) * | 1979-09-21 | 1983-08-30 | Electrolux Siegen Gmbh | Motor-compressor |
US4726738A (en) * | 1985-01-16 | 1988-02-23 | Hitachi, Ltd. | Motor-driven compressor provided with torque control device |
US4656376A (en) * | 1985-06-15 | 1987-04-07 | Danfoss A/S | Motor-compressor unit with offset starting torque |
US5388967A (en) * | 1993-03-10 | 1995-02-14 | Sullair Corporation | Compressor start control and air inlet valve therefor |
US5801500A (en) * | 1995-03-18 | 1998-09-01 | Danfoss A/S | Motor/compressor combination having a control arrangement for starting the motor with asynchronous and then synchronous commutation |
US5988994A (en) * | 1997-10-21 | 1999-11-23 | Global Cooling Manufacturing Company | Angularly oscillating, variable displacement compressor |
US6648604B1 (en) * | 1998-06-05 | 2003-11-18 | Carrier Corporation | Short reverse rotation of scroll compressor at startup |
US6781342B2 (en) * | 2002-05-29 | 2004-08-24 | Bristol Compressors, Inc. | System and method for soft starting a three phase motor |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20080031747A1 (en) * | 2004-05-17 | 2008-02-07 | Koninklijke Philips Electronics N.V. | Reciprocating Pump With Reduced Noise Level |
US8523015B2 (en) * | 2004-05-17 | 2013-09-03 | Koninklijke Philips N.V. | Reciprocating pump with reduced noise level |
US20070085501A1 (en) * | 2005-10-14 | 2007-04-19 | Samsung Electronics Co., Ltd. | Compressor and a driving method thereof |
US7477032B2 (en) * | 2005-10-14 | 2009-01-13 | Samsung Electronics Co., Ltd. | Compressor and a driving method thereof |
US20150048109A1 (en) * | 2012-03-22 | 2015-02-19 | Wuxi Little Swan Co., Ltd. | Dosing Device Overcoming Change In Viscidity Of Detergent And Method For Controlling Same |
US9783921B2 (en) * | 2012-03-22 | 2017-10-10 | Wuxi Little Swan Co., Ltd. | Dosing device overcoming change in viscidity of detergent and method for controlling same |
WO2022109700A1 (en) | 2020-11-25 | 2022-06-02 | Embraco Indústria De Compressores E Soluções Em Refrigeração Ltda. | Piston positioning processes of a reciprocating compressor |
Also Published As
Publication number | Publication date |
---|---|
EP1662143A2 (en) | 2006-05-31 |
CN1782387A (en) | 2006-06-07 |
CN1782387B (en) | 2010-05-12 |
DE502005007559D1 (en) | 2009-08-06 |
ES2327133T3 (en) | 2009-10-26 |
EP1662143B1 (en) | 2009-06-24 |
PL1662143T3 (en) | 2010-01-29 |
DE102004057467B3 (en) | 2006-08-24 |
EP1662143A3 (en) | 2008-11-19 |
ATE434727T1 (en) | 2009-07-15 |
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