ROLL IN A PAPER MACHINE OR PAPER FINISHING MACHINE AND COUPLING ARRANGEMENT FOR THE TENDING-SIDE END OF THE ROLL

Abstract: The invention concerns a roll in a paper machine, such as a suction roll (10) or a variable-crown roll, and a roll in a paper finishing machine, such as a variable-crown roll or a heated roll in a calender for paper, and a coupling arrangement for the tending-side end of the roll. Through the coupling arrangement, energy media are passed into the roll (10), such as pressure fluid and/or compressed air, lubricating media, such as lubrication oil and/or water, and cleaning media, such as hot water. The coupling arrangement comprises an openable shield casing (20), which is connected with the tending-side end of a roll sufficiently tightly. The coupling arrangement comprises a coupling flange (30; 35) or coupling flanges (30, 35), to which the various pipes (15, 16) and/or hoses have been attached. In the interior of the shield casing (20) there are connecting pipes (15a, 15c, 15d, 16a, 16c, 16d) and/or hoses, which connect the pipe parts (15a, 15b) of the roll end with the hose and/or pipe parts (15f, 16f) departing from the coupling arrangement.

Description: Roll in a paper machine or paper finishing machine and coupling arrangement for the tending-side end of the roll The present invention concerns a roll in a paper machine, in particular a suction roll, a variable-crown roll, or a roll in a paper finishing machine, such as a variable- crown roll or a heated roll in a calender for paper. The invention also concerns a coupling arrangement for the tending-side end of a roll in a paper machine, in particular a suction roll or a variable-crown roll, or of a roll in a paper finishing machine, such as a variable-crown roll or a heated roll in a calender for paper, through which coupling arrangement energy media are passed into said roll, such as pressure fluid and/or compressed air, lubricating media, such as lubrication oil and/or water, and cleaning media, such as hot water. The present invention is related to rolls in a paper machine or paper finishing machine and to the coupling arrangements at an end of different process rolls in a paper machine or paper finishing machine. Applications of the invention include at least the following rolls: suction rolls in the former and in the press in a paper machine, SymZL™ rolls in the press, SymBelt™ rolls in the press, and SymBelt™ rolls in on-line or off-line calenders, as well as heated rolls of soft calenders. Through the couplings at the tending-side end of said different rolls in a paper machine, such as suction rolls and variable-crown rolls, and in paper finishing machines, such as variable-crown rolls or heated rolls in calenders, various media are passed into the rolls. These media include, for example, energy media, such as pressurized hydraulic fluid or compressed air, lubricating media, such as lubrication oil or water, and cleaning media, such as pressurized water. Further, in connection with the tending-side end of a roll, there may be various other couplings, such as a pressure equalizing pipe and lubricant exhaust pipe, setting and measurement 2 apparatuses for pressure and for positions of various members fitted inside the roll. For example, in the tending-side end of the forming suction rolls in the former of a paper machine, there are typically 6 large-diameter (e.g., φ = 60 mm) wash water couplings, 10 hydraulic couplings, an exhaust pipe for lubrication fluid at the tending side, display of the meter for the vacuum level in the suction chamber, and devices for indication of the position of the vacuum box, as well as screws for regulation of the positions of the edge seals of the suction chamber. Depending on the extent of equipment, a suction roll in a paper machine includes, for example, the following couplings for the pipe system: at the tending side of the suction roll, a wash water coupling for the roll mantle, a wash water coupling for the suction box, a wash water coupling, 4 loading-air couplings, 3 locking-air couplings, input and outlet couplings for circulation lubrication of the bearing housings, and 2 grease lubrication couplings, and further, at the driving side, there are 2 grease lubrication couplings and input and outlet couplings for circulation lubrication of the bearing housings at the driving side. In the prior- art suction rolls, the vacuum connection for the suction chamber has been arranged through the tubular shaft at the driving side. In the way known from the prior art, said couplings for media placed at the tending side of said rolls communicate with the supply pipes of the various media through flexible metal-fabric reinforced hoses. The hoses have a length of about 1...3 metres, and they are freely suspended. A problem is damaging of the hoses in particular at the wet end of the paper machine. The hoses are curved, and chemicals adhere to the hose faces and harden the face of the hose. As a result of that, the face of the hose cracks, and the metal fabric in the interior of the hose is exposed. The metal fabric corrodes by the effect of the process waters, and there is an obvious risk of failure of the hoses. A damaged hose may cause dangerous situations, and the substance discharged from a hose has usually direct access to the wire circulation and causes even extensive disturbance in production and operation. 3 Failure of said hoses causes a considerable risk for safety at work, in particular so if a high-pressure hydraulic hose or hot-water hose is broken. Owing to this risk of damage, in many paper mills said hoses are replaced, on the average, once in a year for the sake of security. This causes a considerable expense both in the form of the installation work, the material, and in the form of standstills in operation. Said long hoses often extend to the tending platforms and, thus, cause a risk of tumbling and deteriorate the visual contact and the access to the servicing points. Also, damaged oil hoses cause a considerable risk for the environment, because oil that enters into the wire circulation is likely to end up in a waterway. Attempts have been made to counteract damage to the various hoses by means of various fixing means and connecting pieces which keep the hoses apart from one another and, thus, reduce the risk of damage arising from rubbing of the hoses against one another. In the prior-art coupling arrangements for the tending-side ends of the rolls in paper machines, the confusion of the couplings is also a drawback, which confusion is an obvious drawback both in view of the operation and from an aesthetic point of view. A further drawback is the differences between different couplings and the resulting complication and high cost of the spare parts system and of the maintenance. In the way known from the prior art, in calenders for paper, on the cylindrical coupling part at the tending-side end of the calender rolls, a hood-like shield casing has been used, but this casing has not been sealed in any way, nor have the various problems mentioned above and related to the coupling hoses been solved by means of said protective casing. The object of the present invention is to provide overall solutions for the problems and drawbacks dealt with above. It is a particular object of the invention to provide such a coupling for the end of a roll as protects the hoses of transfer of energy and instrumentation from contaminations, such as stock and lye. 4 It is a particular object of the invention to provide such a coupling of the sort concerned by whose means it is possible to increase the service life of the coupling parts and to make the couplings stronger and more solid. It is a further particular object of the invention to improve the visual appearance of the paper machine and to facilitate and to clarify the maintenance operations. It is a non-indispensable further object of the invention to provide such a coupling for the rolls concerned as can be used as an almost standard solution throughout the entire machine, which increases the uniformity of the visual appearance of the machine and facilitates the maintenance and lowers the costs of spare parts. It is a non-indispensable further object of the invention to provide such a coupling of the sort concerned by whose means it is possible to reduce the noise level at least to some extent, for, as is well known, for example, suction rolls are considerable sources of noise. The advantages of the present invention come out with particular emphasis expressly at a suction roll and in the wet end of a paper machine, where the process conditions are highly demanding. However, it should be emphasized that the invention also provides solutions and advantages over the entire length of the paper machine and in paper finishing machines, such as calenders. It is a particular object of the invention to provide such a coupling arrangement of the sort concerned in connection with which it is possible to apply a more concentrated and more protected energy transfer chain. In view of achieving the objectives stated above and those that will come out later, the roll in accordance with the invention is mainly characterized in that the roll is provided with an openable shield casing tightly connected with the tending-side end of the roll. 5 The coupling arrangement in accordance with the invention is mainly characterized in that the coupling arrangement comprises an openable shield casing, which is tightly connected with the tending-side end of the roll. The coupling arrangement further comprises a coupling flange or coupling flanges, to which the various pipes and/or hoses have been attached, and in the interior of said shield casing there are connecting pipes and/or hoses, which connect said pipe parts or equivalent of the roll end with the hose and/or pipe parts departing from the coupling arrangement. In the following, the outlines of the constructional features, advantages and properties of a particularly advantageous embodiment of the invention will be described. In accordance with the invention, a shield casing that can be opened and closed is fitted to the end of the roll, and the lengths of the connecting hoses and pipes of the roll are minimized. To the end of the roll, a connecting plate is attached preferably perpendicularly to the roll end or, alternatively, as parallel to the roll end directly onto the roll end. This plate operates as a multiple terminal coupling for all of the pipes passing into the roll. The passing from the connection plate into the roll takes place by means of fixed hard pipes, which make an elbow of about 90° . The multiple terminal coupling accomplished by means of the connection plate minimizes any errors in the attaching of the hoses. Correspondingly, on the frame, the pipes are passed with optimal concentration to the vicinity of the suction roll. In the hoses, a slack extra length is provided just as needed for turning the suction roll, for example about +7°. The hoses and/or pipes passing to the roll are preferably bundled together by means of a plastic piece, which prevents rubbing of the hoses against one another. Around the hoses, a shield casing is fitted, which can be opened and closed and which prevents access of stock and waters directly onto the faces of the hoses. The shield casing is an integrated part of the suction roll, and in the overall solution of the machine the shield casing may indicate the type of the roll. In such a case, it is 6 possible to see the type of a roll from far apart. The code may be a shield dome of different colour and/or a visible symbol on the casing. An end casing for a roll can be provided in new machines and also in renewals as well as when a new process roll is supplied separately. Longer service life of hoses, improved security, and clarity of layout at the machine are additional values provided by the present invention, which additional values are valuable for a paper mill. The material of the shield casing employed in the present invention must endure the environment in the wet end. The material is, for example, a plastic grade that endures lye and oils very well. The shield casing is manufactured, for example, of a through-coloured plastic by means of a vacuum moulding process or, alternatively, by laminating out of fibreglass. The shield casing must not constitute an obstacle for maintenance operations, and it must not slow down the replacement of a roll, at least not to a substantial extent. Maintenance operations include turning of the interior part ("soul") in a suction roll (there must be visual contact with the scale indicating the position of the inner parts), reading of meters, and lubrication from grease nipples. In connection with the invention, it is possible to employ a support piece which keeps the hoses/pipes tightly in a bundle and prevents their rubbing against one another. The material of the support piece must endure oils and lye, and the bundle arrangement must permit turning of the roll. For a bundle of hoses, a so-called energy transfer chain is a typical shield. If the hoses are not protected, damaging takes place in the same way as earlier and, moreover, replacement of the hoses is more difficult. In the following, the invention will be described in detail with reference to different exemplifying embodiments of the invention illustrated in the figures in the accompanying drawing, the invention being in no way strictly confined to the details of said embodiments. 7 Figure 1 is a sectional view of the end of a suction roll and of a coupling arrangement in accordance with the invention fitted in connection with said roll end, taken along the plane passing through the central axis of the suction roll. Figure 2 shows a coupling arrangement similar to that shown in Fig. 1, wherein the end casing of the suction roll has been pivoted into the open position. Figure 3 shows a second embodiment of the invention in a way corresponding to Figs. 1 and 2, in which embodiment the end casing has been omitted for the sake of clarity of illustration, even though the end casing is an essential part also included in the coupling arrangement shown in Fig. 3. Figure 4 is an axonometric view of a binding piece for hoses and pipes for use in connection with a coupling arrangement in accordance with the invention. Figure 5 is a schematic side view of a typical environment of application of a coupling arrangement in accordance with the invention, i.e. a forming suction roll in a twin-wire former and the further connecting of the coupling arrangement with other connections. Figure 6 is a so-called exploded view of a coupling arrangement in accordance with the invention. Fig. 1 shows a typical construction of the tending-side end of a suction roll 10 and, in its connection, a coupling arrangement in accordance with the invention of the different connecting pipes and hoses. The roll 10 shown in Fig. 1 is, for example, the upper forming suction roll 10, shown in Fig. 5, in the area of the forming gap G in a twin- wire former of a paper machine, but equally well it can be some other roll mentioned above in a paper machine or paper finishing machine, for which roll said hose and pipe couplings are needed for passing of different media and for coupling of other connections. 8 In Figs. 1, 2 and 3, the outer annular frame part 11 and the inner annular frame part 12 of the stationary end of the suction roll 10 are seen, and in Figs. 1 and 2, additionally the vertical end plate 13 is seen, through which the leading-in of the pipes 15,16 takes place. Figs. 1...3 show just two pipe connections passing into the interior of the suction roll 10, but in practice the number of said pipes, hoses and other connections is considerably higher, but in Figs. 1...3 many of them have not been shown, because of clarity of illustration. As is shown in Figs. 1...3, axial fixed pipe portions 15a, 16a enter into the suction rolls 10, which pipe portions have been connected by means of fittings 15b, 16b, through 90° elbow pieces 15c, 16c, to vertical fixed pipe portions 15d,16d. The latter pipe portions 15d,16d have been connected by means of fittings 15e,16e to hose parts 15f, 16f, which are parts of the hose bundle 17 shown in Fig. 5. This hose bundle 17 is connected through a valve plate 18a and related valves 18b with a pipe cassette 18c, from which the different ducts pass further through a lead-in to sources and equivalent of different media and equivalent. As is shown in Figs. 1 and 2, a coupling flange 30 has been fixed by means of an intermediate part 31 in connection with the annular frame part 11 of the suction roll 10. In connection with this coupling flange 30, by means of a connection plate 32 and screws 33, the pipe portions 15d,16d and their fittings 15e,16e have been mounted fixedly and solidly. After the fixed pipe portions 15d,16d and the coupling flange 30, the ducts go on as hoses 15f,16f. In addition to, or in stead of, the coupling 30,31,32,33 shown in Fig. 1, it is possible to use a plate-like coupling flange 35 shown in Fig. 3 and fitted in connection with the inner annular part 12 of the suction roll, to which flange 35 the axial pipe portions 15a, 16a and their fittings 15b, 16b have been fixed by means of the connection plate 36 and the screws 37. The coupling arrangement in accordance with the invention includes a shield casing 20 as an essential part, which casing 20 is fitted in connection with the end of the roll 10 to cover and to protect the various couplings described above and further couplings. The shield casing 20 is connected with the frame part 11 of the roll 10 by 9 means of a hinge joint 23. In Fig. 1, the shield casing 20 is shown in the closed position, in which the inner edge of the shield casing is, at point 24, sufficiently tight in order to prevent access of contaminations into the interior of the shield casing 20. In Fig. 3, the shield casing has been omitted in view of clarity of illustration, even though the casing belongs to the construction shown in Fig. 3 as an essential part. In Fig. 2, the shield casing 20 is shown in the position 20' in which it has been pivoted down around the hinge joint 23, in which case free access is provided to the various couplings and ducts of the roll end for maintenance and installation work etc. As is shown in Figs. 1 and 2, the shield casing 20 consists of a mantle part 21 shaped as a truncated cone and of a dome part 22 connected with it tightly, which dome part has preferably been made transparent so that the connections and possible meters and regulation apparatuses placed inside the shield casing 21 can be examined through the dome part 22 when the shield casing 20 is in the closed position as shown in Fig. 1. In connection with the outer edge of the annular part 11 and/ or with the inner edge of the mantle part 21 placed against said annular part, if necessary, there are appropriate sealing arrangements, which make the shield casing 20 sufficiently tight in its closed position. If necessary, the shield casing 20 is supported in the closed position by means of fastening devices, which are not shown. The mantle part 21 and/or the dome part 22 of the shield casing 20 can be provided with symbols and/ or identification colours, which are distinguished clearly and directly so that the shield casing 20 fitted at the end of the roll 10 concerned clearly identifies the nature of the roll 10 concerned. The dome part 22 does not necessarily have to be transparent, and it can be marked with a identification colour and/or with an identification symbol that is readily distinguishable. Fig. 4 is an axonometric view of a support piece 38, by whose means the different pipes and hoses 17 can be bound together inside or outside the shield casing 20. The support piece 38 consists of parts 38a, 38b, 38c, whose opposite sides are provided with holes 39 for the pipes and/or hoses 17 and/or equivalent connecting parts. From 10 one end, the parts 38a, 38b, 38c are interconnected by means of fastening screws 38d so that the pipes and/ or hoses 17 or equivalent are connected tightly with the holes 39 and, thereby, with the support piece 38. If necessary, the support piece 38 can be connected to some stationary frame part directly or through some intermediate part. Fig. 5 shows a typical environment of application of a coupling arrangement in accordance with the invention, to which environment the invention is, however, by no means confined. A coupling part in accordance with the invention is used, in the way shown in Fig. 5, in connection with the forming suction roll 10 of a twin-wire former in a paper machine. In a way in itself known, the former comprises a headbox 40, and a stock suspension jet J is discharged from the slice gap of the slice part 41 of said headbox 40 into the forming gap G between the forming wires 44 and 45, which gap is defined between the forming suction roll 10 and the breast roll 43. From the shield casing 20 in accordance with the invention for the coupling arrange- ment for the end of the forming roll 10, a protected lead-in 24 departs, through which a bundle of hoses 17 passes, which is, if necessary, joined together by means of a support piece 38 as shown in Fig. 4, and the bundle of hoses is passed to the valve plate 18a and through the valves 18b placed at said plate into a box-like pipe cassette 18c. From here the necessary pipes and couplings are passed further through the lead-in 19 placed in connection with the frame part 50 of the former. In connection with the lead-in 24, on the bundle of hoses 17, there is a shield casing 17a, which is composed of U-section or O-section parts linked together with each other, out of which parts it is possible to assemble curved box parts. In this way a so-called energy transfer chain is formed, which protects the bundle of hoses 17. Above the forming suction roll 10, inside the loop of the carrying wire 45, there is a second upper forming suction roll 42, of which just a part is shown and in whose connection there can also be a coupling arrangement in accordance with the invention with its shield casing 20. Fig. 6 is a so-called exploded view of a variation of the coupling arrangement in accordance with the invention. Fig. 6 shows the roll 10, its bearing support 10A, and the end part 11A of the roll shaped as a truncated cone. Differing from Figs. 11 1...3, the coupling arrangement comprises an annular intermediate part 25 substantially shaped as a truncated cone, which part 25 is attached onto the frame part 11A. To the annular part 25, a coupling casing part 26 is attached, from which a shield casing 27 for the different hoses departs. The shield part 27 is composed, for example, of interlinked mantle portions, which form a so-called energy transfer chain. To the annular part 25 and/or to the coupling casing part 26, one hinge blade of the hinge part 23 is attached so that the connecting part 24 of the shield casing 20 is placed on the coupling casing part 26 when the shield casing 20 is in the closed position. In the other respects, the shield casing 20 is similar to that described above. In the following, the patent claims will be given, and the different details of the invention may show variation within the scope of the inventive idea defined in the patent claims and differ from what has been stated above by way of example only.

Claims: 12 Claims 1. A roll in a paper machine, in particular a suction roll, a variable-crown roll, or a roll in a paper finishing machine, such as a variable-crown roll or a heated roll in a calender for paper, characterized in that the roll (10) is provided with an openable shield casing (20) tightly connected with the tending-side end of the roll. 2. A roll as claimed in claim 1, characterized in that the shield casing (20) comprises a mantle part (21) connected to the roll (10) end, the outer end of said mantle part in the axial direction being provided with a closed end (22). 3. A roll as claimed in claim 2, characterized in that the mantle part (21) of the shield casing (20) is substantially shaped as a truncated cone and becomes narrower outwards from the end of the roll (10). 4. A roll as claimed in claim 2 or 3, characterized in that the closed end of the shield casing (20) comprises a transparent dome part (22). 5. A roll as claimed in any of the preceding claims, characterized in that the mantle part (21) of the shield casing (20) is substantially coaxial with the axis of rotation of the roll (10) connected with said mantle part. 6. A roll as claimed in any of the preceding claims, characterized in that the shield casing (20) has been arranged pivotal substantially around a hinge shaft (23) in view of opening and closing of the shield casing (20) . 7. A roll as claimed in any of the preceding claims, characterized in that the shield casing (20) is provided with a colour and/or a symbol of identification characteristic of each type of roll in view of quick identification of roll types of different natures. 13 8. A roll as claimed in claim 7, characterized in that the shield casings (20) intended for each type of roll have outer appearances similar to one another in view of improving the visual image of the machine. 9. A coupling arrangement for the tending-side end of a roll in a paper machine, in particular a suction roll (10) or a variable-crown roll, or of a roll in a paper finishing machine, such as a variable-crown roll or a heated roll in a calender for paper, through which coupling arrangement energy media are passed into the roll (10), such as pressure fluid and/or compressed air, lubricating media, such as lubrication oil and/or water, and cleaning media, such as hot water, characterized in that the coupling arrangement comprises an openable shield casing (20) tightly connected with the tending-side end of the roll. 10. A coupling arrangement as claimed in claim 9, characterized in that the coupling arrangement also comprises a coupling flange (30;35) or flanges (30,35), to which the various pipes (15, 16) and/ or hoses have been attached, and that in the interior of said shield casing (20) there are connecting pipes (15a, 15c, 15d, 16a, 16c, 16d) and/ or hoses, which connect said pipe parts (15a, 15b) or equivalent of the roll end with the hose and/or pipe parts (15f,16f) departing from the coupling arrangement. 11. A coupling arrangement as claimed in claim 10, characterized in that the connecting pipes placed in the interior of the shield casing (20) are fixed and comprise about 90° elbow parts (15c, 16c), by whose means the axial and substan- tially horizontal pipe parts (15a, 16a) coming from the interior of the roll (10) are turned into fixed, substantially vertical pipe parts (15d, 16d). 12. A coupling arrangement as claimed in any of the claims 9 to 11, characterized in that the shield casing (20) includes an annular part (25), to which a coupling casing part (26) has been attached fixedly, that the annular part (25) is attached fixedly into connection with the end (11 A) of the roll (10), and that, when the shield 14 casing (20) is in the closed position, the mantle part (21) of the shield casing (20) is fitted on the annular part (25) and closes the shield casing (20) tightly. 13. A coupling arrangement as claimed in any of the claims 9 to 12, characterized in that in the shield casing (20), on its outer part in the axial direction, there is a transparent dome part (22), through which the meters and position indicators or equivalent placed inside the shield casing (20) can be read and through which the different parts can be inspected. 14. A coupling arrangement as claimed in any of the claims 9 to 12, characterized in that the coupling flange (30) is attached to the frame of the roll (10) and/or to an intermediate part attached to the side frame of the paper machine. 15. A coupling arrangement as claimed in any of the claims 9 to 14, characterized in that the shield casing (20) comprises a mantle part (21) shaped substantially as a truncated cone, whereas the narrower outer part of the mantle part (21) is provided with a closed end and while the mantle part (21) is provided with a connecting part, in whose connection there is said coupling flange. 16. A coupling arrangement as claimed in claim 15, characterized in that the mantle part (21) shaped as a truncated cone is substantially coaxial with the axis of rotation of the roll (10) connected with said mantle part (21). 17. A coupling arrangement as claimed in any of the claims 9 to 14, characterized in that the shield casing (20) has been arranged pivotal substantially around a hinge shaft (23) in view of opening (Fig. 2) and closing (Fig. 1) of the shield casing (20). 18. A coupling arrangement as claimed in claim 17, characterized in that the hinge shaft (23) is placed in the vicinity of the coupling flange (30). 19. A coupling arrangement as claimed in any of the claims 9 to 16, characterized in that said shield casing (20) is attached to the annular part (11) or equivalent 15 placed in connection with the roll (10) end by means of a bayonet mount or equivalent. 20. A coupling arrangement as claimed in any of the claims 9 to 19, characterized in that several connections in the coupling flange (30;35) have been attached to the coupling flange (30;35) by means of the same locking and tightening flange (32;36). 21. A coupling arrangement as claimed in any of the claims 9 to 20, characterized in that the shield casing (20) includes a connecting part (24), through which the pipe connections have been arranged to pass into the interior of the shield casing. 22. A coupling arrangement as claimed in any of the claims 9 to 21, characterized in that the shield casings (20) of the coupling arrangements at the ends of the different rolls in a paper and/or paper finishing machine have outer appearances similar to one another in view of improving the visual image of the machine. 23. A coupling arrangement as claimed in any of the claims 9 to 22, characterized in that, in view of quick identification of rolls (10) of different natures, each different type of roll has a shield casing of different colour and/ or is provided with a different symbol of identification. 24. A coupling arrangement as claimed in any of the claims 9 to 23, characterized in that the shield casing (20) is provided with a lead-in part (24) protected by an outside mantle, through which lead-in part the bundle of hoses and/or pipes is passed further, being fitted together and protected from outside, preferably to a valve plate (18a) and from it further into a pipe cassette (18c) or equivalent (Fig. 5). 25. A coupling arrangement as claimed in any of the claims 9 to 24, characterized in that, inside and/or outside the shield casing (20), the pipes and/or hoses (17) in the coupling arrangement have been attached and supported together by means of a coupling piece (38), in which the pipes and/or hoses (17) can be tightened together in connection with the holes (39) provided in said coupling piece (Fig. 4).

Inventors: HYVOENEN HANNU, KETTUNEN MIIKKA, SUOMALAINEN JYRI, HYVOENEN, HANNU, KETTUNEN, MIIKKA, SUOMALAINEN, JYRI
Applicants: VALMET CORP, VALMET CORPORATION
Application year: 1999
Main classification: D21G9
IPC codes: D21F3, D21F5, D21G1