Patent Application
20060086812
The present invention is directed to a method for controlling a temperature, to a regulating device, as well as to a device for controlling a temperature.
A device and a method for the temperature control of a component of a printing press is known from DE 44 29 520 A1. The temperature of the component is controlled by use of an at least partially circulating fluid. An actuating member, by use of which a mixture ratio between two fluid flows at different temperatures can be adjusted at a feed-in point, is controlled via a temperature measuring point arranged between the feed-in point and the component.
EP 0 886 577 B1 discloses a device and a method for controlling the temperature of a component. A component temperature is monitored by sensors and the measured value is sent to a control unit. If the temperature measured at the component differs from a command variable, the control unit lowers or increases the temperature of a coolant in a cooling unit by a defined value, waits for a length of time and repeats the measurement and the mentioned steps until the control variable has again been attained.
A temperature control device for printing presses is known from EP 0 382 295 A2. A temperature of the fluid in an inflow section, and a surface temperature of the component whose temperature is to be controlled are detected and are supplied to a control device. A manipulated variable for regulating a mixing motor is determined on the basis of these temperatures, as well as possibly predetermined disturbance variables, such as the paper used, the percentage of dampening agent and target temperatures, which set the relationship between the fluid conducted in the circuit and freshly temperature-controlled fluid.
JP 60-161152 A discloses a cooling device for a roller whose temperature is to be controlled. A surface temperature of the roller, as well as a fluid temperature in the inflow path, are measured and are supplied to a regulating device for comparison with a command variable and for controlling a valve.
The object of the present invention is directed to providing a method for controlling a temperature, a regulating device, as well as a device for controlling a temperature.
In accordance with the present invention, this object is attained by measuring temperature values at several selected points. These values are provided to a regulating device that has at least two regulating circuits. These at least two regulating circuits are connected to each other in a cascade-like manner. The temperature measuring points are spaced apart from each other in a measuring section.
The advantages to be gained by the present invention lie, in particular, in that the regulating device operates very rapidly and dependably, even over existing extended conveying distances for the temperature control medium. The short reaction time allows its employment in applications and processes with large dynamic components. Thus, the instant temperature control is of great advantage even in cases where it is necessary to follow rapid changes of a temperature command variable and/or where external conditions, such as the energy yield, because of friction or external temperatures, change very rapidly.
The rapid regulation in spite of a possibly extended conveying distance for the fluid is achieved for one in that further regulating circuits, and, in particular, two regulating circuits, underlie a regulating circuit monitoring the temperature at the component. Also, in a simplified embodiment, the direct determination of the temperature can be omitted and a further regulating circuit can underlie a regulating circuit that is monitoring the temperature at the entry to the component. Thus, the regulating path from the location of the preparation of the temperature control medium (mixing, heating, cooling) to the destination, such as, for example, the component itself or the entry to the component, is therefore divided into several partial paths and partial running times.
It is of great advantage here that an innermost regulating circuit monitors the temperature of the temperature control medium during its preparation (mixing, heating, cooling) at a very close distance and regulates it, so that an error possibly occurring during processing is detected at the start of the conveying path and is removed by regulation, instead of the error not being detected and steps being taken only taken when it reaches the component.
Embodiments of the present invention are of particular advantage wherein a pre-regulation in regard to the heat flow (losses), in regard to the running times, and/or in regard to the number of revolutions of the machine takes place. A further acceleration of the regulating process can be achieved by a pre-regulation with regard to an amplitude excess and/or with regard to the inclusion of the return temperature.
Preferred embodiments of the present invention are represented in the drawings and will be described in greater detail in what follows.
Shown are in:
The temperature of a component 01 of a machine, such as, for example, a printing press, is to be controlled. The component 01 of the printing press is, for example, a part of a printing group, not represented, and in particular is an ink-conducting roller 01 of a printing group. This roller 01 can be embodied as a roller 01 of an inking system, such as, for example, as a screen roller 01, or as a cylinder 01 of the printing group, such as, for example, a forme cylinder 01. The device and the method for temperature control described in what follows can be particularly advantageously employed in connection with a printing group for waterless offset printing, such as in a printing group operating without the use of a dampening agent. In a printing group, and in particular in a printing group for waterless offset printing, the quality of the ink transfer depends particularly on the temperature of the ink and/or of the ink-conducting surfaces, such as, for example, the shell faces of rollers 01 or cylinders 01. Moreover, the quality of the ink transfer is also sensitive to a splitting speed, such as the number of revolutions of the machine.
Temperature control takes place via a temperature control medium, and in particular via a fluid, such as water, for example, which is brought into thermal interaction with the component 01 along a temperature control path 02. If the fluid is to flow against the component 01, the fluid can also be a gas or a gas mixture, such as air, for example. For temperature control, the fluid is provided to the component 01 in a first circuit 03, flows through or around the component 01, absorbs heat, for cooling or gives off heat, for heating and flows back again, respectively heated or cooled. A heating or cooling unit can be arranged in this first circuit 03, which can be used for providing the desired fluid temperature.
In an advantageous embodiment of the present invention, and in accordance with
The fluid, or a larger portion of the fluid, is circulated in the secondary circuit 03 by the use of a drive mechanism 11, for example by a pump 11, a turbine 11 or in another way, on an inflow path 12 through the component 01, on a return flow path 13 and on a partial path 14 between the inflow and the return flows paths 12, 13. Depending on the inflow via the valve 07, after passing through the component 01, an appropriate amount of fluid flows off via the connection 15 into the secondary circuit 04, or an appropriately reduced amount of fluid flows through the partial path 14. The portion of the fluid flowing back through the partial path 14 and the portion of the fluid which is freshly flowing in via the valve 17 at a feed-in or an injecting point 16 are mixed and now constitute the fluid which is specifically temperature-controlled for the temperature control process. To improve the intermixing, a swirling section 17, and in particular a swirling chamber 17, is arranged as closely as possible downstream of the injection point 16, and in particular between the injection point 16 and the pump 11.
In the above mentioned case, wherein temperature control is not performed bya primary circuit 04, but by a heating or cooling unit, the feed-in or the injection point 16 corresponds to the location of the energy exchange by the respective heating or cooling unit, and the actuating member 07, for example, to an output control or the like. The connecting point 10 in the circuit 03 is omitted, since the fluid circulates altogether in the circuit 03, and energy is supplied or removed, or heat or cold is “fed in” at the feed-in point 16. In this case, the heating or cooling unit corresponds to the actuating member 07, for example.
It is intended in the end, by use of the temperature control, to set or to maintain a defined temperature ⊖3 of the component 01, and in particular in the case of a cylinder 01, the surface temperature ⊖3 on the roller 01, to a defined command variable ⊖3,soll. This is achieved by measuring a statement-capable temperature on the one hand, and by a regulation of the supply of fluid from the primary circuit 04 to the secondary circuit 03 for creating an appropriate mix temperature on the other hand.
It is now important that at least two measuring points M1, M2, M3 with sensors S1, S2, S3 are provided in the instant device, or by the instant method, between the injection point 16 and an exit of the component 01 to be temperature-controlled. One of the measuring points M1 is arranged near the injection point 16, and at least one of the measuring points M2, M3 in an area which is close to the component of the inflow path 12 and/or in the area of the component 01 itself. As a rule, the valve 07, the pump 11, the injection point 16, as well as the connecting points 06, 08 are arranged spatially close to each other and are located, for example, in a temperature control cabinet 18, which is indicated by dashed lines. As a rule, the inflow and the return flow paths 12, 13 between the component 01 and the not explicitly represented exit from, or entry into the temperature-control cabinet 18 have a comparatively great length in regard to the other paths, which is indicated in
In the preferred embodiment of the present invention, in accordance with
Temperature control takes place by a regulating device 21, or a regulating process 21, which will be described in greater detail in what follows. The regulating device 21, as seen in
In a preferred embodiment of the present invention, the corrected command variable ⊖1,soll,k for the first regulator R1 is formed at a node K1′, for example by addition, or subtraction from the value d⊖1 and a theoretical command variable ⊖′1,soll. In turn, the theoretical command variable ⊖′1,soll is formed in a pre-regulation member in regard to the heat flow VWF. The pre-regulation member VWF, in this case V1,WF, subscript 1 for forming the command variable of the first regulating circuit, takes the heat exchange, such as losses etc., of the fluid on a partial path into consideration and is based on empirical values, such asexpert knowledge, calibration measurements, etc. In this way, the pre-regulation member V1,WF takes the heat or cooling losses along the partial path between the measuring points M1 and M2 into consideration in that it forms an appropriately raised or lowered theoretical command variable ⊖′1,soll, which is then processed, together with the value d⊖1, into the corrected command variable ⊖1,soll,k for the first regulator R1. A connection between the input value, i.e. the command variable ⊖3,soll or ⊖′2,soll or ⊖′2,soll,n, as discussed below, and a corrected output value, such as a modified command variable ⊖′2,soll or ⊖′2,soll,n, see below, or ⊖′1,soll,n, is fixedly stored in the pre-regulation member VWF, which can preferably be changed by parameters, or in another way, as needed.
In principle, a simple embodiment of the regulating device is possible, wherein only the two first mentioned regulating circuits form the cascade regulating device. In this case, the pre-regulation member V1,WF would be specified as the input value by a machine control device, or by a defined command variable ⊖2,soll manually. It would also be used for forming the above mentioned deviation Δ ⊖2 upstream of the second regulator R2.
However, in the embodiment of the invention which is represented in
The corrected command variable ⊖2,soll,k for the second regulator R2 is formed at a node K2′, by, for example addition, or subtraction from the value d⊖2 and a theoretical command variable ⊖′2,soll, or ⊖″2,soll, see below. In turn, the theoretical command variable ⊖′2 soll is formed in a pre-regulation member in regard to the heat flow V2WF. The pre-regulation member V2WF, for example takes the heat or cooling losses on the partial path between the measuring points M2 and M3 into consideration by forming an appropriately raised or lowered command variable ⊖′2,soll which then, together with the value d⊖2, is processed as the corrected command variable ⊖2,soll,k for the second regulator R2.
Thus, the above-described method is based, for one, on the measurement of the temperature directly downstream of the injection point 16, as well as on at least one measurement taken close to the component 01 whose temperature is to be controlled. Secondly, a particularly short reaction time of the regulation is achieved in that several regulating circuits interact in a cascade-like manner and that in the course of the command variable formation for the inner regulating circuit, a measured value ⊖2, ⊖3 is taken into consideration. Thirdly, a particularly short reaction time is achieved by pre-regulation, which provides empirical values for losses to be expected on the temperature control path 02. Thus, a regulation circuit, which is located closer to the actuating member 07, is already provided with a command variable that is appropriately raised or lowered by an empirical value in expectation of losses.
In an advantageous embodiment of the present invention, in accordance with
As can be seen in
Based on the idle time, which corresponds to running time TL2 or T′L3 and the time constant Te2 or T′e3, the path reactions to the activities of the innermost regulator R1, toward the level of the two outer regulators R2, R3, do not become immediately visible. In order to avoid, or to prevent, a double reaction of these regulators caused by this, which would be exaggeratedly wrong and which could not be recovered, a pre-regulation member, in regard to the running time and/or to the time constant VLZ and in the form of a path model member, is provided in one or in several of the control circuits in the course of forming the command variable, by the use of which the expected “natural” delay in the result of a change at the actuating member 07 is taken into consideration. The running time actually required by the fluid, determined, on the basis of empirical values or preferably by measured value recordation, or by calculated estimates is simulated in the regulation by the pre-regulation member in regard to the running time and/or to the time constant VLZ. Now, the outer regulators M2, M3 only react to those deviations which, taking into consideration the modeled path properties, are not expected and which therefore actually require repair. The outer regulators R2, R3 are “blinded” by this symmetrization to the regulation deviations which are expected anyway and which are physically unavoidable, and of which deviations the innermost regulator R1 already takes care of “locally”. In this way, the “pre-regulation member” VLZ acts in the manner of a “running time and delay member” VLZ. The above-mentioned dynamic property, running time and delay is mapped in the pre-regulation member VLZ and is permanently stored, but can preferably be changed, as needed, by parameters or in another way. To this end, appropriate parameters T*L2, T*e2, T*L3, T*e3, which are intended to simulate and to represent, for example the actual running time TL2, T′L3 and/or the replacement constant Te2, Te3, can be adjusted at the pre-regulation member VLZ. The adjustment should take place in such a way that, with this, a virtual dynamic course of the command variable created by calculation, for example the command variable ⊖″2,soll or ⊖″3,soll, is compared, substantially synchronously in time, with the corresponding course of the measured value ⊖2 or ⊖3 of the temperature at the associated sensor S2 or S3 and the node K2 or K3.
For the outer regulating circuit, the virtual changed command variable ⊖″3,soll corresponds to the command variable ⊖3,soll,k which is to be compared with the measured value, since it is not corrected by a further regulating circuit. In the preferred embodiment, no pre-regulating member VLZ besides it is provided in the innermost regulating circuit, having very short paths or running time. In a unification of the nomenclature, here the command variable ⊖′3,soll therefore represents the command variable ⊖″3,soll without any further changes.
Such a pre-regulation member VLZ, which represents the path model, is provided at least for forming the command variable for the regulating circuit or the regulating circuits assigned to the sensor S2, or to the sensors S2, S3 close to the component. In the example, the two outer regulating circuits have such a pre-regulating member VLZ,2, VLZ,3 in their command variable formation process. If the path between the valve 07 and the sensor S1 should also prove to be too long and too interfering, it is also possible to provide an appropriate pre-regulation member VLZ,1 in the command value formation process for the inner regulating circuit.
A further improvement of the regulating dynamics can be achieved with the further development of the above-mentioned regulating device, in accordance with
To prevent any stability problems, this step preferably takes place only in the portion of the command variable not affected by actual values, i.e. ahead of the respective node K1, K2′, addition or subtraction point depending on the mathematical sign. To maintain this symmetrization at the outer regulators R2, R3, this dynamic step then must be compensated there by use of appropriate derivative members VVH,2 or VVH,3, which act, in addition to the mentioned pre-regulations VWF, in regard to the heat flow and VLZ, in regard to the running time and/or the time constants during the formation of the command variable of the subsequent regulating circuit.
The property of the course of the mentioned excess increase, in relation to the input signal is mapped in the pre-regulating member VVH,1 and is permanently stored, but its size or course can be changed as needed, preferably by parameters or in other ways. In accordance with the physical sequence, the derivative member VVH,1, in regard to the signal path, is preferably arranged ahead of the pre-regulating member VLZ, if provided, and behind the pre-regulating member VWF, if provided. The pre-regulation member VVH, in accordance with one of the embodiments of FIGS. 1 to 4, can also be used independently of, or in addition to, the presence of the pre-regulation members VLZ, VDZ or VAB, see below.
In a further development of the regulating devices of the present invention, and in accordance with
In order to further increase the dynamics of the regulating device 21, in particular under changing operating conditions, such as during a start-up phase, during a change in the number of revolutions, or the like, the pre-regulating member VDZ in regard to the number of revolutions is provided, which can basically be superimposed on all lower-order command valuable formations, which therefore have an actuating value character, i.e. the formation of the command variables ⊖′1,soll, ⊖″2,soll, ⊖″3,soll. However, a superimposition of the outer regulating circuit does not make sense as long as the value measured at the sensor S3 represents the technologically final valid actual value, for example the temperature on the effective surface, i.e. on the shell face itself. In the preferred embodiment, the pre-regulating member VDZ only acts on the formation of the command variables ⊖″1,soll, ⊖″2,soll, namely in that a correction value d⊖n is superimposed on the theoretical command variable ⊖′2,soll created in the pre-regulating member V2,WF, which is arranged upstream of the second regulating circuit. The command variable ⊖′2,soll,n, which is created from this, is used directly, or via appropriate pre-regulation members VVH,1 and/or VLZ,1, for forming the command variable of the second regulating circuit R2, and simultaneously via pre-regulating member VWF,1, and possibly the pre-regulating member VVH,I for forming the command variable of the first regulating circuit (R1). A connection between the number n of revolutions of the machine and a suitable correction is permanently stored in the pre-regulating member VDZ, which can preferably be changed, as needed, via parameters or in other ways. The pre-regulating member VDZ can also be used in one of the embodiments in accordance with FIGS. 1 to 4 independently of the presence of the pre-regulating members VLZ, VVH or VAB, or in addition.
However, if the sensor S3 does not measure the shell face, but measures a temperature further inside of the component which technologically is not the final valid temperature, it can also be useful to let the pre-regulation member VDZ also act on the outer regulating circuit, R3. The same applies to an outer regulating circuit which obtains the measured value not directly from the component 01, but from a sensor S4, S5, see
In a further development, as depicted in
The functional progress, and the amplification of the pre-regulating member VNU regarding this return flow pre-regulation are permanently stored and can preferably be changed by parameters.
The regulators R1, R2, R3 from the preferred embodiments in accordance with FIGS. 1 to 4 are embodied in a simple design as PI regulators R1, R2, R3.
However, in an advantageous embodiment of the present invention, at least the regulators R2 and R3 are designed as so-called “running time-based regulators” or “Smith regulators”. The running time-based regulators R2 and R3, in particular running time-based PI regulators R2 and R3 are represented in
The running time or the idle time of the regulating path, as well as its time constant, is mapped in the running time-based PI regulator R2, R3 and is permanently stored, but can preferably be changed via parameters or in other ways, as needed. For this purpose, appropriate parameters T**L2, T**e2, T**L3, T**e2, which, for example, are intended to represent the actual running time TL2 or TL3, and/or the time constant Te2, Te3, can be set at the PI regulator R2 and R3. With a correct setting and reproduction of the regulating path, the values of the parameters T**L2, T**e2, T**L3, T**e3, and the values of the parameters T*L2, T*e2, T*L3, T*e3 from the pre-regulating members VLZ,1, in regard to the running time and the time constant, should substantially agree, since the respective regulating path is described by them in the regulator R2, R3, as well as in the pre-regulation member VLZ. Accordingly it is possible to use running time-based PI regulators R2, R3, as well as pre-regulating members VLZ in the regulating device, and the same parameter sets, once determined, should be used for both.
The first section 12.1 extends from the injection point 16 as far as the first measuring point M1 with the first sensor S1 and has a path length X1, as well as a first average running time TL1. The second section 12.2 extends from the first measuring point M1 up to a measuring point M2 “near the component”, with the sensor S2. It has a second path length X2, as well as a second average running time TL2. The third section 12.3 with a third path length X3, as well as a third average running time TL3, adjoins the measuring point M2 and extends to the destination 22 (here the first contact of the fluid in the area of the extended shell face). A total running time T of the fluid from the injection point 16 to the destination therefore results from TL1+TL2+TL3.
The first measuring point M1 has been selected “close to the feed-in point”, i.e. at a short distance from the feed-in point 16, here the injection point 16. Thus, a measuring point M1 close to the feed-in point, or a sensor S1 close to the actuating means is understood to be a location in the area of the inflow path 12, which is located in regard to the running time TL of the fluid less than one tenth, in particular one-twentieth, of the distance from the feed-in point 16 to the first contact with the destination 22 (here the first contact of the fluid in the area of the extended shell face), i.e. TL1<0.1 T, in particular TLI<0.5 T applies. For a high degree of regulation dynamics, the measuring point M1 is located in respect to the running time TL1 of the fluid maximally 2 seconds, in particular maximally 1 second, distant from the injection point 16. As already mentioned in connection with
As a rule, the component 01 and the temperature-control cabinet are not arranged directly adjoining each other in the machine, so that a line 26, for example pipes 26 or a hose 26, from the temperature-control cabinet 18 to an entry 27 into the component 01, for example to a lead-through 27, in particular a rotary lead-through 27, has a length of appropriate size. The lead-through into the roller 01 or the cylinder 01 is only schematically indicated in
The third measuring point M3, if provided, is also arranged at least “close to the component”, but in particular “close to the destination”. This means that it is located in close vicinity to the destination 22 of the fluid, or directly detects the surface to be temperature-controlled (in this case the shell face of the roller 01). In an advantageous manner the measuring point M3 does not detect the fluid temperature, such as is the case with the measuring points M1 and M2, for example, but the area to be temperature controlled of the component 01 itself. The direct vicinity of the destination 22 is here understood to mean that the sensor S3 is located between the fluid circulating in the component 01 and the shell face, or detects the temperature ⊖3 on the shall face in a contactless manner.
In another embodiment of the temperature-control device it is possible to do without the measuring point S3. It is possible to draw conclusions regarding the temperature ⊖3 from empirical values by means of the measured values of the measuring point M2, for example by means of a stored connection, an offset, a functional interrelationship. Then, for a desired temperature ⊖3 a regulation to a desired temperature ⊖2 is performed, taking into consideration the machine or production parameters (inter alia the number of revolutions of the machine, ambient temperature and/or fluid throughput, (doctor blade) coefficient of friction, heat progress resistance).
In a further embodiment the measuring point 3 is again omitted, but conclusions regarding the temperature ⊖3 are drawn from empirical values by means of the measured values at the measuring point M2 and the measuring point M4, for example again from a stored connection, an offset, a functional interrelationship and/or by forming an average value from the two measured values. Then for a desired temperature ⊖3, a regulation to a desired temperature ⊖2 as the command variable is performed again, either by taking into consideration the machine or production parameters (inter alia the. number of revolutions of the machine, ambient temperature and/or fluid throughput), or to the temperature ⊖3 indirectly determined by means of the two measured values. In
In the advantageous embodiment of the temperature-control device, it has a swirling section 17, in particular a specially designed swirling chamber 17, in the section 12.1 between the feed-in point 16 and the first measuring point M1. As already mentioned above, the measuring point M1 should be arranged close to the feed-in point, so that as rapid as possible reaction times can be realized in the respective regulation circuit with the measuring point M1 and the actuating member 07. However, on the other hand a homogeneous mixture between the fed-in and the returning fluid (or the heated/cooled fluid) has not yet been achieved closely downstream of the feed-in point, so that errors in the measured values make regulation difficult, and possibly considerably delay reaching of the desired temperature ⊖3 at the component 01.
The employment of the swirling section 17, in particular of the specially designed swirling chamber 17, in accordance with
Initially, a first cross-sectional change takes place in the smallest structural space, wherein a first cross-sectional surface A1 is suddenly increased by a factor f1=2 to a second cross-sectional surface A2. Directly adjoining a change in direction of 70° to 110° takes place, in particular abruptly by approximately 90°, which is followed by a second cross-sectional change, namely a reduction from the cross-sectional surface A2 to the cross-sectional surface A3 by a factor f2 (f2<1). The factor f2 is advantageously selected as f2<0.5 and has been selected complementary to the factor f1 in such a way that the two cross-sectional surfaces A1, A3 upstream and downstream of the swirling chamber 17 are substantially of the same size.
While preferred embodiments of a temperature control method, a regulating device, and a temperature control device, in accordance with the present invention have been set forth fully and completely hereinabove, it will be apparent to one of skill in the art that various changes in, for example, the source of supply of the temperature control fluid, the specific structure of the printing press, and the like could be made without departing from the true spirit and scope of the present invention which is accordingly to be limited only by the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10258927.5 | Dec 2002 | DE | national |
| 10328234.3 | Jun 2003 | DE | national |
This patent application is the U.S. national phase, under 35 USC 371, of PCT/DE2003/004098, filed Dec. 11, 2003; published as WO 2004/054805 A1 on Jul. 1, 2004; and claiming priority to DE 102 58 927.5, filed Dec. 17, 2002 and to DE 103 28 234.3, filed Jun. 24, 2003, the disclosures of which are expressly incorporated herein by reference.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/DE03/04098 | 12/11/2003 | WO | 6/17/2005 |
