Apparatus for Displacing the Roll Mantle End Pieces of a Shoe Press
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Europäisches Patentamt *EP001273699A1* (19) European Patent Office Office européen des brevets (11) EP 1 273 699 A1 (12) EUROPEAN PATENT APPLICATION (43) Date of publication: (51) Int Cl.7: D21F 3/02 08.01.2003 Bulletin 2003/02 (21) Application number: 02077507.8 (22) Date of filing: 01.07.2002 (84) Designated Contracting States: (72) Inventor: Aho, Erkki AT BE BG CH CY CZ DE DK EE ES FI FR GB GR 47200 Elimäki (FI) IE IT LI LU MC NL PT SE SK TR Designated Extension States: (74) Representative: AL LT LV MK RO SI Järveläinen, Pertti Tauno Juhani et al Heinänen Oy (30) Priority: 05.07.2001 FI 20011476 Annankatu 31-33 C 00100 Helsinki (FI) (71) Applicant: Vaahto OY 15860 Hollola (FI) (54) Apparatus for displacing the roll mantle end pieces of a shoe press (57) An apparatus for displacing the roll mantle end the roll mantle so that the mantle together with the back- pieces of shoe press, said shoe press comprising a ing roll can form a pressing zone, two roll mantle end press roll (1) and a backing roll, said press roll (1) com- pieces (6, 7) axially movable on each stub shaft, fasten- prising a rotating, liquid-impermeable roll mantle (2), a ing elements for fastening the axial ends of the roll man- solid and preferably non-rotatable support beam (3) go- tle to each roll mantle end piece. The apparatus com- ing axially through the roll mantle and having a stub shaft prises a multi-chamber cylinder unit (8) functionally con- (4, 5) at each end of it, at least one press shoe supported nected to both roll mantle end pieces, said cylinder unit by the support beam and having a concave surface part, being disposed inside the support beam (3) and used to elements for pressing the concave surface part against move both roll mantle end pieces (6, 7). EP 1 273 699 A1 Printed by Jouve, 75001 PARIS (FR) 1 EP 1 273 699 A1 2 Description is locked in place and the roll mantle is stretched in the opposite direction. The stretching direction is changed [0001] The present invention relates to an apparatus automatically after a given elongation or period of time. as defined in the preamble of the independent claim 1 The apparatus presented in this specification comprises presented below for displacing the roll mantle end piec- 5 actuators at each end of the roll mantle, which are used es of a shoe press. to stretch the roll mantle alternately in opposite direc- [0002] A typical shoe press comprises a press roll and tions. a backing roll, and the press roll comprises a flexible [0006] In the apparatuses described above, the hy- rotating roll mantle impermeable to liquid, a fixed and draulic actuators used to stress the roll mantle are preferably non-rotatable support beam going axially 10 mounted on the surface of the support beam, and in or- through the roll mantle and having a stub shaft at each der to achieve a uniform stress, probably at least three end of it, at least one press shoe supported by the sup- actuators are needed for each end. The use of a plurality port beam and having a concave surface part, elements of separate actuators increases the space requirement for pressing the concave surface part against the elastic and need for maintenance of the system, resulting in a roll mantle so that the mantle together with the backing 15 complicated system. roll can form a pressing zone, two roll mantle end pieces [0007] The object of the method and apparatus of the axially movable on each stub shaft, fastening elements present invention is to eliminate or at least to reduce the for fastening the axial ends of the roll mantle to each roll problems associated with the above-described prior-art mantle end piece, and at least one element for tighten- solutions. ing the elastic roll mantle and/or moving it axially on 20 [0008] A further object of the invention is to achieve a each respective stub shaft. The elastic roll mantle may method and an apparatus for tightening the roll mantle have properties permitting stretching in the widthways of a shoe press and/or reducing its wear, which can be direction of the machine during operation or the roll man- used with both stretchable and non-stretchable roll man- tle may be of substantially constant width. tles. An additional object is to achieve an apparatus that [0003] It is generally known that the roll mantle of a 25 is simple and reliable in respect of operation as well as shoe press as described above has to be tightened dur- control. ing operation. Another known problem with a long nip [0009] To implement the aforesaid objects, among type press as described above is wear of the roll mantle other things, the method and apparatus of the invention in the region of the axial ends of the press shoe, which for tightening a shoe press roll mantle and/or reducing is a consequence of the large local stresses that the roll 30 its wear are mainly characterized by what is said in the mantle under-goes as it passes through the press zone. characterization parts of the independent claims pre- Therefore, the useful life of the roll mantle is short and sented below. the mantle has to be replaced at regular intervals, lead- [0010] A feature typical of the method of the invention ing to interruptions and reduction of production. is that, as a means for tightening and/or displacing the [0004] An example of solutions designed to eliminate 35 roll mantle axially on the respective stub shaft, at least the above-described problem is that presented in patent one actuator disposed inside the support beam and specification FI 100012. This specification discloses an functionally connected to both roll mantle end pieces is apparatus in which the roll mantle is moved manually in used to move both roll mantle end pieces simultaneous- the axial direction by means of mechanical retainers ly relative to each other. The actuator disposed inside about once a week. The tightening of the roll mantle is 40 the support beam and functionally connected to the roll performed using hydraulic cylinders. The hydraulic cyl- mantle end pieces consists of a three-chamber pres- inders are so fitted that they only act on one end of the sure-medium operated cylinder, the pressure ratios be- roll mantle while its other end remains locked in place. tween the chambers of which are varied. In the method When the roll mantle has been stretched by a certain of the invention, instead of a three-chamber cylinder, it length, it is moved into a new position while the tighten- 45 is also possible to use a cylinder with more than three ing is active all the time. A mantle stretching mechanism chambers or a number of two-chamber cylinders con- is used for functional reasons to keep the roll mantle in nected in series. 'Three-chamber cylinder' in the present shape. In the apparatus described in the specification, context refers e.g. to a cylinder comprising two movable the elongation of the roll mantle is not utilized in any way, pistons and three pressure medium spaces, the pistons but the mantle stretching apparatus is only used to keep 50 being moved by varying the pressure in each chamber. the roll mantle functional as it tends to stretch during The cylinder, preferably a hydraulic cylinder, is immov- operation. ably locked in place on the center line of the machine. [0005] Patent specification FI 101319 discloses a [0011] The main advantage afforded by the method method and apparatus designed to eliminate the prob- of the invention is that, by placing the actuator moving lems associated with the apparatus of the above-de- 55 the roll mantle end pieces inside the support beam, the scribed specification, in which method one end of the displacement of the roll mantle end pieces can be ad- roll mantle is first locked in place and the second end is vantageously implemented using a single actuator. This acted on by a an actuator, whereupon the second end allows cost and space savings to be achieved. 2 3 EP 1 273 699 A1 4 [0012] In a preferred method according to the present both roll mantle end pieces simultaneously. In addition, invention, the tightening of the roll mantle is performed by implementing the displacement of the roll mantle in by controlling the pressure in the middle chamber of a the above-described manner, a substantially constant three-chamber cylinder. Controlling the pressure in a roll mantle tightness is maintained both during the dis- chamber here means that the chamber is supplied with 5 placement and during the change of direction of dis- a pressure medium in such manner that a desired pres- placement. sure is maintained in the chamber. The middle chamber [0015] When the roll mantle is of a type that stretches is set to a higher pressure than the outer chambers. The during operation of the shoe press, it does not neces- pistons of the actuator are forced to move simultane- sarily have to be moved to reduce wear of the roll man- ously in opposite directions, and correspondingly the roll 10 tle. By virtue of the fact that the roll mantle is tightened mantle end pieces are moved in opposite directions and simultaneously in opposite directions according to the the roll mantle is tightened. By reducing the pressure present invention and because the roll mantle stretches, prevailing in the middle chamber, the roll mantle be- those areas of the roll mantle that are subjected to great- comes slacker or its slackening becomes possible.