IMPROVED FRAME CONSTRUCTION AND METHOD IN A PAPER MACHINE PRESS SECTION FOR FACILITATING REPLACEMENT OF PRESS ROLLS AND FABRICS

Abstract: A frame construction and method in a paper machine press section having a compact press roll combination (13, 16, 21, 31) forming at least two press nips (NÉ, NÊ, NË) through which a paper web (W) runs, the frame construction and method facilitating the removal and replacement of the fabrics and/or press rolls. The frame construction includes a front frame (50) situated before the press roll combination and a rear frame (70) separate from the front frame situated after the roll combination. The space above the roll combination and between the front and rear frames is opened or openable by pivoting an intermediate frame (60) situated above the roll combination into an open position.The replacement of fabrics and press rolls are carried out by utilizing the open space obtained by pivoting the intermediate frame. The intermediate frame comprises two separate frame parts, namely, a front intermediate frame (60a) which is pivoted around horizontal articulated joints (62a) attached to the front frame (50), and a rear intermediate frame (60b) is pivoted around horizontal articulated joints (62b) attached to the rear frame (70). The intermediate frame is closed by coupling the outer parts thereof to a stationary intermediate frame (60c) part mounted, for example, on the bearing housings of the center roll (16) of the press.

Description: BACKGROUND OF THE INVENTION The present invention relates to a method for replacing one or more press rolls and/or press fabrics in a paper machine press section having a compact press roll combination including press rolls forming at least two press nips with each other between which a web is adapted to run in a longitudinal machine direction and press fabrics passing through the press nips, the press section further including a frame construction on which the press rolls are mounted including a front frame situated before the roll combination in the direction of the web run through the press section and a rear frame situated after the roll combination in the direction of web run through the press section, the frame construction having a service side and an operating side. The invention also relates to a frame construction of a paper machine press section having a compact press roll combination including press rolls forming at least two press nips with each other between which a web is adapted to run in a longitudinal machine direction and press fabrics passing through the press nips, the frame construction on which the press rolls are mounted comprising a front frame situated before the roll combination in the direction of web run through the press section; a rear frame separate from the front frame, situated after the roll combination in the direction of web run through the press section; and an intermediate frame arrangement situated above the roll combination interconnecting the front and rear frames, the intermediate frame arrangement being movable from a closed position to an open position by actuating means to create an open space above the roll combination so that at least one of the press rolls and press fabrics can be removed and replaced through the open space when the intermediate frame arrangement is in the open position. A method and a frame construction of this type are disclosed in an article "La moderna sezione presse per carta da stampa" published in the Italian magazine "Industria della Carta", November 1984, Vol. 22, n. 11. In this article the so-called "flip-top" concept of Beloit Corporation is presented. In the frame construction of conventional compact press sections of paper machines, such as in the SYM-PRESS paper machine press section available from Valmet Oy of Finland, front and rear frames are provided before and after the compact press roll combination which are permanently connected to each other by horizontal beams located at both the operating and service sides of the paper machine. As used herein, "front frame" means the frame part that is situated before the compact press roll combination in the direction of web run through the press section and on which the upper press roll, conventionally a suction roll, of the first press nip is usually mounted. Correspondingly, "rear frame" means the frame part which is situated after the press roll combination. Conventional frame constructions for compact paper machine press sections present difficulties in connection with the replacement of the press fabrics and press rolls. These problems have become more serious as the widths of the paper machines have increased since the press rolls are longer and heavier. Moreover, additional problems have been created by the increasing use of press fabrics formed of plastic materials. When formed of plastic, the press fabrics tend to be substantially rigid in the transverse direction which prevents the press fabrics from being compressed into a small volume, since this would cause the fabrics to become wrinkled and therefore not useable. In an attempt to overcome the problems described above, Beloit Corporation of Beloit, Wisconsin has suggested a frame construction, designated as its "flip-top" concept mentioned above, wherein either the top part of the front frame or the top part of the rear frame can be opened by rotating it about a pivot shaft whose axis is parallel to the transverse direction of the paper machine and which is situated above the press rolls. As a consequence of this construction, the two top parts of the frames cannot be opened at the same time. In order to replace the pick-up fabric of a press section incorporating a "flip-top" frame construction, which fabric usually functions as the press fabric in the first and second press nips, the top part of the front frame is opened. During this procedure, however, the top part of the rear frame must be locked since the top part of the front frame, when opened, is supported on the top part of the rear frame. In a corresponding manner, the top part of the rear frame can be opened, such as in connection with the replacement of the press fabric in the third press nip, only when the top part of the front frame is closed and locked in position. The lower fabric of the first nip, which runs mainly in the basement space, is replaced by means of conventional arrangements. The "flip-top" frame construction described above can be characterized as a type of "drawbridge" which is openable at an articulated joint which is situated in the middle of the drawbridge directly above the conpact roll combination and wherein only one-half of the bridge can be opened at any one time. In applicant's US-A-4 608,l25 a method and press section for applying the method are disclosed in which a space situated above the press roll combination and between the front and rear frames is opened or openable by pivoting an intermediate frame into an open position. The pivoting is performed around an articulated joint associated with the rear frame at the side of the roll combination and the open space is utilized, directly or indirectly, in the replacement of at least the pick-up fabric and the upper fabric of the press and/or in the re-placement of one or more press rolls of the roll combination. SUMMARY OF THE INVENTION An object of the present invention is to provide an improvement in the method and apparatus of the "flip-top" concept and to provide an alternative method and press section frame construction for applying the method. Another object of the present invention is to provide a frame construction of a press section which can be opened in a more simple and rapid manner than that of the "flip-top" construction. Briefly, in accordance with the present invention, these and other objects are attained by providing a method which is of the type mentioned by way of introduction and which is characterised in that it comprises in combination the steps of providing an openable space above the compact press roll combination by arranging an intermediate frame arrangement between the front and rear frames, the intermediate frame arrangement including a front intermediate frame having inner and outer ends and being pivotally mounted on the front frame at the inner end thereof by first pivot means having an axis extending transversely of the longitudinal machine direction, a rear intermediate frame having inner and outer ends and being pivotally mounted on the rear frame at the inner end thereof by second pivot means having an axis extending transversely of the longitudinal machine direction; and a stationary intermediate frame part to which the outer ends of the front and rear intermediate frames are attachable to close the space; the front and rear intermediate frames being pivotable to open positions separately to open the space; opening the space by pivoting at least one of the front and rear intermediate frames; and removing and replacing one or more press rolls and/or press fabrics through the open space above the roll combination. The frame construction of a press section in accordance with the invention is of the type described by way of introduction and is further characterised in that the intermediate frame arrangement comprises a front intermediate frame pivotally mount ed on the front frame by first pivot means having an axis extending transversely of the longitudinal machine direction; a rear intermediate frame pivotally mounted on the rear frame by second pivot means having an axis extending transversely of the longitudinal machine direction, a stationary intermediate frame part; means for attaching the front and rear intermediate frames to the intermediate frame part when the intermediate frame arrangement is in its closed position; first actuating means associated with the front intermediate frame for pivoting the same between closed and open positions; and second actuating means associated with the rear intermediate frame for pivoting the same between closed and open positions; whereby the front and rear intermediate frames are separately openable and closeable. Further features of the invention are stated in the appended claims. The present invention differs from the method and frame construction disclosed in applicant's US-patent 4 608 125 in that in accordance with the present invention, the intermediate frame comprises two pivoting parts, one of which is pivotally connected to the front frame and the other of which is pivotally connected to the rear frame, and wherein the intermediate frame can be locked in the closed position by means of locking members situated at the outer ends of the pivoting intermediate frame parts, the locking members being coupleable onto a suitable stationary frame part which preferably comprises components associated with the frames in which the journal bearings of the center roll of the press are mounted. Comparing the present invention to the "flip-top" construction of Beloit Corporation, the present invention can be characterized as a "drawbridge" construction which is openable about articulated joints placed at both ends of the drawbridge so that, if necessary, both halves of the drawbridge can be opened at the same time into the open position thereby rendering the construction simpler in construction and use and openable in a more rapid manner. DETAILED DESCRIPTION OF THE DRAWINGS A more complete appreciation of the present invention and many of the attendant advantages thereof will be readily understood by reference to the following detailed description when considered in connection with the accompanying drawings in which: FIG. 1 is a side elevation view of a press section of a paper machine in accordance with the invention and illustrating the intermediate frame arrangement in the closed position; FIG. 2 is a side elevation view of the press section illustrated in FIG. 1 illustrating the replacement of press rolls while the intermediate frame arrangement is in its open position; and FIG. 3 is a side elevation view of the press section illustrated in FIGS. 1 and 2 and illustrating the replacement of the pick-up and press felts of the press section. DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings wherein like reference characters designate identical or corresponding parts throughout the several views, the press section shown in FIGS. 1, 2 and 3 comprises a closed press roll combination including rolls 13, 16, 21 and 31 which together form three successive press nips N₁, N₂ and N₃ between them. The press section also includes a fourth, separate press nip N₄ formed between press rolls 33 and 43 (FIGS. 2 and 3). The press section includes first and second fabrics (usually felts) l0 and 20 which run through the first press nip N₁. The first fabric l0 acts as a pick-up fabric and also as a press fabric in the second press nip N₂. A third press fabric 30 runs through the third press nip N₃ and a fourth press fabric 40 comprises a lower press fabric and passes through the fourth press nip ₄. A pick-up roll ll is situated within the loop of the first fabric l0. Pick-up roll ll has a suction zone which acts to transfer the web from the forming fabric 27 onto the run between rolls ll and l3. Fabric l0 is guided by guide rolls l2. The run of second fabric 20 is guided by guide rolls 22 while the run of the third fabric 30 is guided by guide rolls 32. The fourth fabric 40 acts to shift the web W from the point facing the transfer roll l8 into the last press nip N₄ and is guided by suction-transfer rolls 4l and 42 as well as by guide rolls 42′. The run of the web W from the pick-up point P through the press section is as follows. The suction sector of the pick-up roll ll detaches the web W from the wire 27 and attaches it onto the bottom face of the fabric l0 on which the web W passes through the twin-fabric nip N.₁. The lower roll 2l of nip N₁ is provided with a hollow face 2l′. After the nip N₁. The web W follows the first fabric under the effect of suction sector l3a of suction roll l3. In the second nip N₂, the web W is transferred onto the smooth face l6′ of center roll l6 on which it is carried into the third nip N₃ after which the web W follows the center roll l6 and is then guided by transfer roll l8 onto the fabric 40 within the suction sector of the suction roll 4l and further onto the other suction roll 42. The web is supported by the fabric 40 as it enters the last nip N₄. The construction and operation of the press section described above are generally known and are described herein merely by way of background for the invention and as an example of one type of compact press section with which the present invention can be utilized. The method and frame construction of the invention can also be applied in a compact press section in which the web has open draws and it is understood that the press rolls can be mounted and installed in a manner different from that shown in the drawings. The frame construction of the press section includes a front frame 50 to the top portion of which an auxiliary frame 5l is pivotally mounted by means of articulated joints 52 having a horizontal pivot axis. The guide rolls of the first fabric l0 are mounted on the auxiliary frame 5l. One of the guide rolls is mounted on a tensioning device 54 in order to provide suitable tensioning of fabric l0. The front frame 50 is provided with intermediate pieces 35 and 55 which can be opened for replacing the first fabric l0. In accordance with the invention, the frame construction includes a rear frame 70 to the front side of which a rear intermediate frame 60b is pivotally connected by means of a projecting part 7l so as to pivot about horizontal pivot shafts 62b. The rear intermediate frame 60b is situated partly above the compact roll arrangement l3, l6, 2l and 3l. The center roll l6 of the press is journalled about a fixed axis of rotation on its own frame part l9. As seen in FIGS. 2 and 3, both the operation and service sides of the front frame 50, the auxiliary frame 5l, and the lower frame are interconnected by cantilever beams ll0, lll and ll4 which are supported at one end by traction members (not shown) on the lower beam. The plane of the floor of the paper machine building is designated 50l. As seen in FIG. l, the intermediate frame arrangement 60 comprises two parts, namely a front intermediate frame 60a and the rear intermediate frame 60b. The front intermediate frame 60a is pivotally linked to the front frame 50 by means of horizontal articulated joints 62a. The front intermediate frame 60a is pivoted around the horizontal shafts 62a by actuating means 64a′. The front intermediate frame 60a comprises substantially V- or L- shaped lateral parts which are attached by means of a connecting part 65a to an intermediate part 60c of the intermediate frame arrangement 60. The intermediate part 60c is itself attached to bearing housings l7 fixedly mounted to the frame part l9 of the center roll l6 of the press. Intermediate frame parts l4 are attached to the front intermediate frame 60a by means of horizontal articulated joints l5 and the suction roll l3 of the press is mounted on the intermediate frame parts l4. The intermediate frame parts l4 can be pivoted relative the front intermediate frame 60a by means of power units l4a which also serve to apply a load in nips N₁ and N₂. Still referring to FIG. l, the rear intermediate frame 60b of the intermediate frame 60 is pivotally linked to the projecting parts 7l of the rear frame 70 by means of horizontal articulated joints 62b and can be opened and closed by actuating means 64b. The press roll 3l is journalled on the rear intermediate frame 60b by means of the frame part 67b to form the third press nip N₃ with center roll l6. The press roll 3l can be shifted to the open position 3l′ relative to the rear intermediate frame 60b by power units 68b which also serve to apply a load in nip N₃. The side beams of the rear intermediate frame 60b are substantially U-shaped (when viewed from the side) and are attached to the stationary intermediate frame part 60c of the intermediate frame 60 at their ends opposite to the points of articulation 62b by means of a connecting part 65b when the intermediate frame 60 is in the closed position. The intermediate frame arrangement 60 described above and shown in FIG. l thus comprises two frame parts 60a and 60b in addition to a stationary part 60c which interconnects the same and can be opened and closed for the purposes described above. Replacement of the rolls of the press section in accordance with the method of the invention is illustrated in FIG. 2. The upper auxiliary frame 5l of the front frame 50 is pivoted around the pivot shafts 52 into the open position 5l′ by opening the joints 53a, 53b. The auxiliary frame 5l may also be stationary in which case it becomes cantilevered when the fabric l0 is replaced. In the case where the auxiliary frame 5l is pivotable as shown in FIG. 2, it does not have to be pivoted during replacement of a roll. Prior to replacing the roll, the fabric within the loop of which the roll to be replaced is situated is removed. As shown in FIG. 2, lifting ropes 95 are attached to the journals of the suction roll ll′ to enable the suction roll to be lifted on the hooks 90 of a traverse crane. The suction pick-up roll ll′ is then replaced in a conventional manner. Before press rolls l3, l6, 2l and 3l are lifted, the joints 65a and 65b of the intermediate frame 60a, 60b are opened and the intermediate frames 60a, 60b pivoted from the closed position shown in FIG. l to the vertical-open position 60a′ 60b′ shown schematically in FIGS. 2 and 3. In this manner a free space T having an open top is created through which the lifting of the press rolls l3, 2l, l6 and 3l can be accomplished. The suction roll l3 of the compact press section is suspended from lifting cables 96 which are attached to the lifting hook 9l. Suction roll l3 is lifted upwardly and shifted to the side of the press section while at the same time turning it in space T. Subsequently, the lower roll 2l of the first nip N₁ is lifted in the same way by means of lifting cables 96′. The suction roll l3 may be lifted either by its axle journals by means of a pair of lifting ropes or by a center-lifting technique by means of lifting lines. When intermediate frames 60a, 60b are in the open positions 60a′, 60b′, the press roll 3l of the third press nip N₃ can also be replaced, also by center-lifting, by means of lifting ropes or lines 98 attached to lifting hooks 93. Prior to replacing roll 3l, roll 32c is shifted along the path designated a₂ to a temporary holding site 32a′. After the third fabric 30 has been removed or the tensioning roll for fabric 30 shifted to the holding site 32a′, a free space T₁ is opened above the fourth press nip N₄. Space T₁ is opened at its upper end so that the press rolls 33 and 43 can be lifted by center-lifting. In accordance with FIG. 2, the press roll 33 is lifted by lifting lines 99 attached to lifting hooks 94 while the lower roll 43 is lifted by lifting lines 99′. The term "center-lifting" as used above means that the rolls are suspended from a single crane hook supported by lifting lines which support the roll in a downwardly opening inverted V-shape symmetrically at both sides of the vertical central plane. The centerlifting technique has the advantage that the roll can be pivoted in the horizontal plane around its vertical central axis which facilitates the shifting of the rolls even in crowded conditions.On the other hand, where a roll is lifted by its axle journals, the longitudinal direction of the roll usually remains fixed since the operation of two cranes in cooperation is a difficult and dangerous procedure. The replacement or servicing of rolls ll, l3, 2l, 3l, 33 and 43 has been described above in connection with FIG. 2. In practice, however, it is usually the case that only a single roll requires replacement or servicing at any one time in which case only the necessary fabrics are removed and the necessary frame parts opened. Referring to FIG. 3, the replacement of all of the fabrics l0, 20, 30 and 40, is illustrated. It is understood, however, that it is not always the case that all of the fabrics are replaced at the same time. In the replacement of the first fabric l0, the auxiliary frame 5l of the front frame 50 is pivoted about shaft 52 to the open position 5l′ or, in the case where the auxiliary frame 5l is stationary, it is cantilevered and the tensioning roll for fabric l0 supported on the part 54 of auxiliary frame 5l is shifted to the holding site l2a′ along the path designated by arrow a₁. In the replacement of the first fabric l0, the suction roll l3 is shifted to the side position l3′ by pivoting the intermediate frame 60a to the vertical-open position 60a′ and the intermediate pieces 35 and 55 of the front frame 50 at the service side of the machine are opened so that open gaps V are formed in the frame through which gaps the felt loop l0′ is passed. In the replacement of the second fabric 20, the suction roll l3 is shifted to the side position l3′, the press roll 2l is moved to the lower position, and the intermediate pieces 25 and the frame 26 are opened. In the replacement of the third fabric 30, the intermediate pieces 72 and 73 are opened and the tensioning roll for fabric 30 is shifted along the path a₃ to the holding site 32′ located above the rear frame 70. The intermediate frame 60b is pivoted into the open position 60b′ while at the same time the press roll 3l and the guide rolls 32c and 32d (FIG. 1) are also pivoted into the inner positions whereby the open space T is formed to facilitate replacement of fabric 30. In the replacement of lower fabric 40 of the fourth press nip N₄, the intermediate pieces 72, 74, 75 and 45 as well as nip N₄ are opened, whereby the replacement of the fourth fabric 40 may be accomplished through the open top space T₁. The roll of felt 400 is pushed along a rail (not shown) which is situated in the space between the intermediate pieces 72 and 74 of the machine. Referring to FIG. 3, the roll l00 of the first fabric which is supported on a pole carried by lifting wires l0l is carried to the service side of the paper machine. A loop l0′ is unwound from roll l00 which is then passed through the spaces V and through the open press nips N₁ and N₂ to its operating position around the cantilever beam lll whereupon the roll l2a′ is shifted to its operating position and the auxiliary frame 5l′ pivoted into the closed position with its joints 53a, 53b being fastened. In the replacement of the second fabric 20, the roll 200 of the second fabric wrapped around a pole carried by wires 20l is brought to the side of the paper machine whereupon a loop 20′ is unwound from roll 200 and passed through the open spaces V and through the opened first nip N₁ to its operating position around the cantilever beams. Preliminarily, the tensioning and alignment rolls of the fabric 20 which are situated in the basement space below the floor level 50l are shifted to the upper position below roll 2l to the level of the cantilever beams ll4, such as by means of apparatus of the type disclosed in Finnish Patent Application No. 80 3020. corresponding to EP-A-00 60877. At this point, the pole supporting the roll 200 is shifted on its carrying wires 20l towards the space T in the position shown in FIG. 3 whereby the second fabric 20 becomes positioned in its operating position around the cantilever beams ll4 when the nip N₂ is opened to a sufficient extent. In the replacement of the third fabric 30, a loop 30′ is unwound from a roll 300 wound around a pole carried by wires 30l. The loop 30′ is passed through the spaces V around the various rolls 3l, etc., situated around the cantilever beams ll3. In the replacement of the fourth fabric 40, a technique similar to the replacement of fabric 20 is utilized so that when the fourth nip N₄ is in the open position, a loop 40′ of fabric is passed from the roll 400 carried by wires 40l around the cantilever beams ll5 in the manner shown in FIG. 3. The operations carried out in connection with the replacement of the various felts and rolls are disclosed in applicant's US-A-4 608 125 filed April 25, l985, now allowed. In the manner described above, the fabrics l0, 20, 30 and 40 can be replaced by a procedure which is more advantageous than in the prior art so that during replacement of the fabrics, adequate space is available for the various operations, primarily as a result of the frame parts 60a and 60b being openable to a positon most favorable for replacement of fabrics. The frame parts 60a and 60b can be opened simultaneously or, alternatively, only one of them can be opened at any time, as required. It is seen from FIG. 3 that at least partly due to the method and frame construction of the present invention, the rolls to be situated inside the loops of the fabrics which are replaced can be situated in a very small space close to each other so that the free loop to be unwound from the fabric rolls and which is fitted around the various rolls and cantilever beams can be made relatively small and preferably substantially drop-shaped which facilitates the insertion of the fabrics. Regarding the replacement of fabrics, the method in accordance with the invention is advantageous where the fabrics are made of plastic which cannot be wrinkled to a bundle in the lateral direction. As noted above, the invention can also be applied to press sections of other configurations than that specifically shown and described herein. For example, the invention can be applied to press sections avialable from applicant's assignee, Valmet Oy of Finland, under the trademarks SYM-PRESS I and SYM-PRESS II, the former having only two press nips, i.e., press nips N₁ and N₂, and no separate nip N₄, the latter having three nips N₁, N₂ and N₃ without any separate nip N₄. In such cases, either the third and the fourth fabrics or the fourth fabric, respectively, are omitted.

Claims: A frame construction of a paper machine press section having a compact press roll combination including press rolls (13, 16, 31, 21) forming at least two press nips (N₁, N₂, N₃) with each other between which a web (W) is adapted to run in a longitudinal machine direction and press fabrics (10, 20, 30) passing through the press nips, the frame construction on which the press rolls are mounted comprising a front frame (50) situated before the roll combination in the direction of web (W) run through the press section; a rear frame (70) separate from the front frame (50), situated after the roll combination in the direction of web (W) run through the press section; and an intermediate frame arrangement (60) situated above the roll combination interconnecting the front and rear frames (50, 70), the intermediate frame arrangement being movable from a closed position to an open position by actuating means (64a', 64b) to create an open space (T) above the roll combination so that at least one of the press rolls (13, 16, 31, 21) and press fabrics (10, 20, 30) can be removed and replaced through the open space (T) when the intermediate frame arrangement (60) is in the open position, characterised in that the intermediate frame arrangement (60) comprises a front intermediate frame (60a) pivotally mounted on the front frame (50) by first pivot means (62a) having an axis extending transversely of the longitudinal machine direction; a rear intermediate frame (60b) pivotally mounted on the rear frame (70) by second pivot means (62b) having an axis extending transversely of the longitudinal machine direction, a stationary intermediate frame part (60c); means (65a, 65b) for attaching the front and rear intermediate frames (60a, 60b) to the intermediate frame part (60c) when the intermediate frame arrangement (60) is in its closed position; first actuating means (64a') associated with the front intermediate frame (60a) for pivoting the same between closed and open positions; and second actuating means (64b) associated with the rear intermediate frame (60b) for pivoting the same between closed and open positions; whereby the front and rear intermediate frames (60a, 60b) are separately openable and closeable. The frame construction of claim 1, wherein the compact press roll combination includes a central press roll (16) and means (17) for mounting the same and wherein the intermediate frame part is associated with the mounting means (17) for the central press roll (16). The frame construction of claim 1 or 2, wherein the attaching means include first locking means (65a, 65b) provided on outer ends of the front and rear intermediate frames (60a, 60b) and second locking means (65a, 65b) provided on the intermediate frame part (60c), the first and second locking means (65a, 65b) being adapted to lockingly engage when the intermediate frame arrangement (60) is in said closed position, wherein the intermediate frame arrangement (60) interconnects said front and rear frames to form a rigid frame unit. A method for replacing one or more press rolls and/or press fabrics (10, 20, 30) in a paper machine press section having a compact press roll combination including press rolls (13, 16, 31, 21) forming at least two press nips (N₁, N₂, N₃) with each other between which a web (W) is adapted to run in a longitudinal machine direction and press fabrics (10, 20, 30) passing through the press nips (N₁, N₂, N₃), the press section further including a frame construction on which the press rolls (13, 16, 31, 21) are mounted including a front frame (50) situated before the roll combination in the direction of web (W) run through the press section and a rear frame (70) situated after the roll combination in the direction of web (W) run through the press section, the frame construction having a service side and an operating side, characterised in that the method comprises in combination the steps of providing an openable space (T) above the compact press roll combination by arranging an intermediate frame arrangement (60) between the front and rear frames (50, 70), the intermediate frame arrangement (60) including a front intermediate frame (60a) having inner and outer ends and being pivotally mounted on the front frame (50) at the inner end thereof by first pivot means (62a) having an axis extending transversely of the longitudinal machine direction, a rear intermediate frame (60b) having inner and outer ends and being pivotally mounted on the rear frame (70) at the inner end thereof by second pivot means (62b) having an axis extending transversely of the longitudinal machine direction; and a stationary intermediate frame part (60c) to which the outer ends of the front and rear intermediate frames (60a, 60b) are attachable to close the space (T); the front and rear intermediate frames (60a, 60b) being pivotable to open positions separately to open the space (T); opening the space (T) by pivoting at least one of the front and rear intermediate frames (60a, 60b); and removing and replacing one or more press rolls (13, 16, 31, 21) and/or press fabrics (10, 20, 30) through the open space (T) above the roll combination. The method of claim 4, wherein the compact press roll combination includes a central press roll (16) and means (17) for mounting the same, the intermediate frame part (60c) being associated with the mounting means (17) for the central press roll (16); and further including locking means (65a, 65b) provided on the intermediate frame part (60c) for locking the outer ends of the front and rear intermediate frames (60a, 60b) thereto. The method of claim 4 or 5, wherein the compact press roll combination includes a suction roll (13) forming first and second press nips (N₁, N₂) with additional press rolls (21, 16), the suction roll (13) being mounted on a first frame component (14) articulated to the front intermediate frame (60a); and wherein first actuating means (14a) are provided for pivoting the first frame component (14) for loading at least one of the first and second press nips (N₁, N₂). The method of claim 4, 5 or 6, wherein the compact press roll combination comprises a center roll (16) and an additional press roll (31) forming a third press nip (N₃), the additional roll (31) being mounted on a second frame component (67b) articulated to the rear intermediate frame (60b); and wherein second actuating means (68b) are provided for pivoting the second frame component (67b) for loading the third nip (N₃). The method of claim 4, 5, 6 or 7, wherein the compact press roll combination comprises a suction roll (13) and a center roll (16) and wherein the step of removing the suction and/or center roll (13, 16) is performed by a center-lifting technique including initially shifting the roll (13, 16) towards a service side of the paper machine in the axial direction of the roll (13, 16) and then turning the roll (13, 16) about a vertical central axis thereof into the machine direction, said turning being accomplished with one end of the roll (13, 16) situated in the space (T).

Inventors: AUTIO, MARKKU
Applicants: VALMET PAPER MACHINERY INC.
Application year: 1986
Main classification: D21F3
IPC codes: D21F7, D21F3