|Title of Invention||
PROCESS FOR SETTING THE LINE STRENGTH IN A WORKING GAP OF A ROLLER PAIR AS WELL AS A DEVICE FOR CONDITIONING A WEB OF MATERIAL
|Abstract||In a method for setting the linear force in the working gap of a pair of rollers which comprises at least one roller that can be hydraulically controlled in terms of its deflection and a pneumatically actuated device for adjusting the rollers, in which method the setting of the linear force is performed by presetting a pneumatic actuating pressure and adapting the hydraulic pressure in the sense of minimizing the linear force error, the hydraulic pressure values that are assigned to the pneumatic pressure values for the entire working spectrum of the pair of rollers (3) are stored in a data memory (15) and are used for activating at least one electro-pneumatic proportional valve (19, 19') to actuate the device for adjusting the rollers (L 2) and for activating a hydraulic source (34) providing the hydraulic actuating pressure for the at least one roller that can be controlled in terms of its deflection.|
PROCESS FOR SETTING THE LINE STRENGTH IN A HEAD GAP OF A ROLLER PAIR AS WELL AS A DEVICE FOR CONDITIONING A GOODS
The invention is with regard to a process for setting the line strength in a head gap of a roller pair that comprises at least one hydraulic sag-controllable roller and one pneumatically operated device for employment of the rollers in the case of which, setting the line strength takes place by specifying a pneumatic operating pressure and aligning the hydraulic pressure in the sense of minimising the line strength error, as well as a device for conditioning a goods track with a roller pair that forms a head gap of which at least one roller is designed as a hydraulic sag-controllable roller and with one pneumatically operable device for employment of rollers, whereby setting the line strength in a head gap takes place by specifying a pneumatic operating pressure and aligning the hydraulic pressure in the sense of minimising the line strength error.
This type of device serves, for example, for wet processing of a goods track and is established in EP-A-1 256 650, for example, in the form of a padding machine. This comprises a trough in which a goods track coming from a guide roller is inserted from top to bottom whereupon a deflection roller circles the floor of the trough and is guided vertically upwards out of the trough in order to run through the roller pair after passing a spreader roller located above, the head gap of the roller pair serving to squeeze off excess processing fluids.
In the case of this roller pair, one of the two rollers is located in the chassis of the device to be movable in the sense of opening and closing the head gap, A pneumatically operable device is provided to close the head gap, whereby the
squeeze force required for the respective application is set by specifying the pneumatic operating pressure.
In order to achieve a uniform squeeze result along the goods track, a line strength error that is caused by sagging of the rollers has to be corrected. As is known, at least one of the two rollers is designed as a hydraulic sag-controllable roller in which a rotating roller shell is supported on a crosshead that penetrates the roller shell. If a so-called "fish belly" profile forms as a result of reaction forces acting upon the rollers in the roller clearance due to which the gap width is larger in the central region than the edges when seen in a direction axial to the rollers, then this fish belly profile can be at least partially counterbalanced by loading the at least hydraulic sag-controllable roller with hydraulic pressure to such an extent that the same results in a sag-correction of the roller shell in the sense of an essentially constant roller clearance and therewith to an essentially constant squeeze effect along the entire breadth of the goods track.
Since the hydraulic pressure required for line strength correction is definitely subject to the extent of line strength pre-determined by the pneumatic pressure, it is established that a pneumaticaliy/hydraulically acting ratio controller be inserted, said controller controlling the hydraulic pressure with which the at least one sag-controllable roller is impacted, subject to the pneumatic pressure that sets the rollers and, therewith, essentially determines the extent of the line strength.
A device belonging to prior art and that is structured in this manner is presented schematically in Figure 2.
The disadvantage in this type of a device is that the operating capacities of the pneumatically/hydraulically acting ratio controller are restricted so that the device cannot be operated in the entire line strength region that would have been covered by the rollers adjacent to the head gap.
The objective forming the basis of the invention is, therefore, to create a process for setting the line strength in the head gap of a roller pair and a device respectively for conditioning a goods track, particularly for wet processing of a goods track of the type mentioned initially, said device permitting conditioning of the goods tracks in a greater line strength range in a roller clearance formed between two rollers.
This objective Is met by the process reproduced in Claim 1.
Since hydraulic pressures allocated to the pneumatic pressures are stored in a data memory for the entire operating spectrum of the roller pair and since this data can be used to control at least one electro-pneumatic proportional valve for operation of the device with which to set the rollers and can be used to control hydraulic operating pressure for the at least one sag-controllable roller, the pneumatically/hydraulically acting ratio controller can be omitted. The line strength range in which the goods track conditioning can take place is thus only limited by the rollers adjoining the roller clearance. Over and above this, a significantly improved correction of the line strength error can take place, compared to prior art, by selecting the function according to which the hydraulic pressures are allocated to the pre-determined, pneumatic pressures.
Using the corresponding data, it is basically possible to, on the one hand, control electro-pneumatic proportional valves for operating the device to set the
rollers that comprise, for example, pneumatically operable pistons/cylinder units or inflatable bellows and, on the other hand, to control an electro-hydraulic proportional valve to control the operating pressure for the at least one sag-controllable roller.
It has, however, been demonstrated that with regard to controlling a device that influences hydraulic pressure, the type most suited is the one that is operated pneumatically at the primary side. Accordingly, an electro-pneumatic proportional valve is preferably controlled using data for the hydraulic pressures and the pneumatically operated device that influences hydraulic pressure controlled by means of the resulting pneumatic pressure.
It is, thus, especially preferred that the device be designed as a pneumatic-hydraulic proportional valve.
In order to improve line strength correction further, it is preferred that the pneumatic and hydraulic pressures be measured and the metered values be used to compare default/actual values.
These could then, as is particularly preferred, be supplied to a regulating device that influences the pneumatic and hydraulic pressures in the sense of minimising the difference between the default and actual values. Constructively, this can take place by feeding the difference values to an electronic device that corrects data taken from the data memory by the registered difference value.
The device for conditioning the goods track according to the invention reproduced in Claim 6 thus comprises a data memory in which hydraulic pressures allocated to the pneumatic pressures for the entire operating spectrum of the roller pair are stored. A data memory is designed in a programmable control system that comprises signal outputs which are adjacent to electrical signals correlating to the pneumatic and hydraulic pressures, whereby signal outputs are effectively connected to the device influencing pneumatic and/or hydraulic pressures.
The devices that influences pneumatic pressure preferably comprise an electro-pneumatically acting proportional valve.
The device influencing hydraulic pressure also comprises an electro-pneumatically acting proportional valve that is especially preferred and that is effectively connected at the pneumatic side to a device to influence hydraulic pressure that can be designed as, for example, a pneumatically operable hydraulic overflow valve.
It is particularly preferred that the device comprise pneumatically/electrically and/or hydraulically/electrically acting metering devices for registration of the pneumatic and hydraulic operating pressures since values registered by means of these metering devices could then be used to correct signals giving the pneumatic and/or hydraulic pressures, whereby regulating these pressures is possible in the narrow sense of the word.
The invention will now be explained further by means of the enclosed drawing that is a schematic presentation of block diagrams of the invention (Figure 1) and a device (Figure 2) belonging to prior art.
A device according to the invention comprises a squeeze roller pair 3 made up of an upper roller 1 and a lower roller 2, whereby rollers 1, 2 form a head gap between them through which a goods track is guided when both rollers 1, 2 are in use.
The rollers are designed as hydraulic, sag-controllable rollers with an established design, that comprise a roller shell pivoting on a crosshead, that can be impacted by a hydraulic force via hydraulically acting devices from the inside in the direction of the head gap 6.
In the embodiment presented in Figure 1, the rollers are designed as so-called S-rollers in which the region within the roller shell, facing the roller clearance and the region facing away from the roller clearance can be loaded with varying high hydraulic pressures. For this purpose, rollers 1, 2, have feed pipes 7, 8 for pressurised hydraulic fluids that act together with pressure chambers up to the head gap 6, said chambers not being illustrated in the drawing.
Hydraulic fluids are fed via throttles 9, 10 to one of the pressure chambers respectively acting in an opposite direction so that roller shells 4, 5, are supported in a swimming manner on respectively associated crossheads under a resulting force that is effective up to the head gap 6. Hydraulic fluid is discharged via discharge pipes 11,12 after passing through rollers 1, 2.
Lower roller 2 is supported in such a manner in the chassis, which is not illustrated in the drawing, that it can be moved to open and close the head gap 2, Pneumatically operable bellows 13, 14 act respectively at both ends of its crosshead as is indicated by line L in Figure 1 The lower roller 2 is employed
against the upper roller 1 when compressed air impacts bellows 13, 14 and, in fact, with a line strength that is subject to the extent of the pneumatic pressure that impacts upon bellows 13, 14.
The greater the pressure in the bellows 13, 14 and therewith the line strength in the head gap 6, the stronger the tendency of the roller shells 4, 5 to sag in the central region in their axial direction in the sense of increasing the head gap 6. In order to counteract this tendency, roller shells 4, 5 are impacted upon from the inside by hydraulic pressure in the regions that face the head gap 6, the extent of this pressure having to be higher than the pneumatic pressure employed.
In order to execute this increase in hydraulic pressure, subject to the pneumatic pressure employed across at least almost the entire operating range of rollers 4, 5, the device according to the invention has a data memory 15 designed as a programmable control system in which hydraulic pressure values allocated to pneumatic pressure values are stored for correction of the line strength error for the entire operating spectrum of roller pair 4, 5.
Data memory 15 is connected to analogous outputs 16, 17 at which an electrical signal characterising a pressure value respectively is present.
Output 16 is connected to an electro-pneumatic proportional valve 19 that reduces the pneumatic pressure provided by a compressed air source 20 to a desired value, subject to the electrical input signal. The pneumatic output of proportional valve 19 is connected by a pressure pipe 21 to the input of the volume amplifier 22 that, subject to the pressure present at the primary side through pipe 21, permits streaming in of a compressed air volume through pipe
23 to bellows 13 till the required pneumatic pressure has built up in the same for achievement of the desired line strength in head gap 6. The latter is facilitated by coupling a measurement connection 24 to pipe 23, the former's end being connected to the pressure-voltage converter 25 that allocates the registered pressure value in the electrical signal and feeds input 27 of the programmable control system 30 comprising the data memory 15 through an electrical line 26. The signal at output 16 is corrected with the thus registered difference between the actual and default values till the desired pneumatic pressure is present in the pressure-voltage convertor 25.
Output 18 of the programmable control system 30 is connected to bellows 14 through an interconnection of the same components that are thus indicated by the same reference signs which are, however, augmented by a '. Metering of the pneumatic actual value in bellows 14 again takes place by coupling a pressure-voltage convertor 25' via line 24', whereby the electrical output of pressure-voltage convertor 25' is connected by electrical line 26' to input 28 for the purpose of default-actual value compensation.
Electrical output 17 of the programmable control system 30 is, likewise, connected to an electro-pneumatic proportional valve 29 at whose output pneumatic pressure made available by the compressed air source 20 is present reduced by a pre-determined reduced amount by the electrical signal present at output 17. This reduced, pneumatic pressure lies above a pressure pipe 31 at the control input of a pneumatic-hydraulically acting overflow valve 32.
Overflow valve 32 is connected through a hydraulic feed pipe 33 to a hydraulic source 34, hydraulic fluid being available under a required pressure in a required quantity. Hydraulic fluid is fed through feed pipes 7 and 8 to rollers 1,
2, subject to the pneumatic control pressure present through the pressure pipe
A pressure-voltage convertor 36 is connected to hydraulic pipe 35 via a measurement connection 38 for the purpose of default-actual value comparison. Its output is connected to an electrical line 39 with input 40 of the programmable control system 30 so that influencing the signal present at output 17 again by means of the same can be undertaken in the sense of a default-actual value comparison.
In contrast to this, in the device belonging to prior art that is illustrated in Figure 2, only control of the hydraulic pressure subject to the pneumatic pressure takes place mechanically through a pneumatic, arithmetic and logic unit 37 encompassing a ratio regulator, whereby due to the limited operating capacities of the pneumatically/hydraulically acting ratio regulator, the operating capacity of the roller pair 1, 2, cannot be utilised.
LIST OF REFERENCE SIGNS
1. Upper roller
2. Lower roller
3. Squeeze roller pair
4. Roller shell
5. Roller shell
6. Head gap
7. Feed pipe
8. Feed pipe
11. Discharge pipe
12. Discharge pipe
15. Data memory
19. Proportional valve
20. Compressed air source
21. Pressure pipe
22. Volume amplifier
24. Measurement connection
25. Pressure-voltage convertor
26. Electrical line
29. Pressure-voltage convertor
30. Programmable control system
31. Pressure pipe
32. Overflow valve
33. Hydraulic feed pipe
34. Hydraulic source
35. Hydraulic feed pipe
36. Pressure-voltage convertor
37. Arithmetic and logic unit
38. Measurement connection
39. Electrical line
1. Process for setting the line strength in a head gap of a roller pair that comprises at least one hydraulic, sag-controllable roller and a pneumatically operable device for engaging the rollers in which setting of line strength takes place by pre-determining a pneumatic operating pressure and aligning the hydraulic pressure in the sense of minimising the line strength error, characterised in that, hydraulic pressure values allocated to the pneumatic pressure values are stored for the entire operating spectrum of the roller pair (3) and that this data can be used to control at least one electro-pneumatic proportional valve (19, 19') to operate the device for engaging rollers (1, 2) and to control hydraulic source (34) provided for the hydraulic operating pressure for the at least one sag-controllable roller.
2. Process according to Claim 1, characterised in that, an electro-pneumatic proportional valve (29) can be controlled using data for the hydraulic pressure and that the pneumatically-operated device influencing hydraulic pressure can be controlled by means of the resulting pneumatic pressure.
3. Process according to Claim 2, characterised in that, the device comprises a pneumatically-hydraulically acting overflow valve.
4. Process according to one of Claims 1 to 3, characterised in that, the pneumatic and hydraulic pressures are metered and the metered values are used to compare the default-actual value.
5. Process according to Claim 4, characterised in that, the default-actual values are fed to a regulating device that influences pneumatic and
hydraulic pressures in the sense of minimising the difference between the default and actual values.
6. Device for conditioning a goods track with a roller pair (3) that forms a head gap (6) of which at least one roller (1, 2) is designed as a hydraulic, sag-controllable roller and with a pneumatically operable device for engaging the rollers, whereby setting the line strength in the head gap (6) takes place by providing a pneumatic operating pressure and alignment of the hydraulic pressure in the sense of minimising the line strength error, characterised in that, the device is a data memory (15) in which hydraulic pressure values allocated to pneumatic pressure values for the entire operating spectrum of the roller pair (3) are stored and that the data memory (15) is provided in a programmable control system (30) comprising signal outputs (16, 17, 18) at which electrical signals that correlate to the pneumatic and hydraulic pressures lie, whereby the signal outputs (16, 17, 18) are effectively connected to the devices (19, 19', 29) influencing pneumatic and/or hydraulic pressure.
7. Device according to Claim 6, characterised in that, the device (19, 19', 29) influencing pneumatic pressure comprises an electro-pneumatically acting proportional valve (19, 19', 29).
8. Device according to Claim 6 or 7, characterised in that, the device influencing hydraulic pressure comprises an electro-pneumatic acting proportional valve (29) that is effectively connected on the primary side to a device with which to influence hydraulic pressures.
9. Device according to Claim 8, characterised in that, the device with which to influence hydraulic pressure comprises a pneumatically operable, hydraulic overflow valve (32).
10. Device according to Claim 9, characterised in that, the pneumatically/electrically and/or hydraulically/electrically acting metering
devices (25, 25', 36) are provided to register pneumatic and hydraulic operating pressures.
|Indian Patent Application Number||1731/CHENP/2008|
|PG Journal Number||10/2013|
|Date of Filing||04-Apr-2008|
|Name of Patentee||Kusters Textile GmbH|
|Applicant Address||GERHART-HAUPTMANN-STRASSE 15 02763 ZITTAU|
|PCT International Classification Number||D06B 15/02|
|PCT International Application Number||PCT/EP06/08233|
|PCT International Filing date||2006-08-22|