CA1307688C - Method in the press section of a paper machine for the replacement of fabrics and/or rolls as well as a frame contruction of the press section for the application of the method - Google Patents

Abstract

Abstract of the Disclosure Method and frame construction for the press section of a paper machine, in particular for a so-called compact press section, which comprises a compact press roll combination These rolls form two or more press nips with each other, and the paper web runs between the said nips. By means of the method, the fabrics and/or the said press rolls are replaced.
The press section comprises, in the direction of running of the paper web , a front frame placed before the said press roll combination and a rear frame placed after the said roll combination.
The space placed above the said roll combination and between the said front frame and rear frame is arranged open or, alternatively, as openable by pivoting a particular intermediate frame or frames into an open position. The said pivoting is performed around an articulated joint or joints transverse to the longitudinal direction of the paper machine and placed at the side of the said roll combination . By making use of the said open space directly or in-directly, the replacement of at least the pick-up fabric and of the upper fabric , if any, of the press and/or the replacement of one or several rolls of the said press roll combination are carried out.

Description

I ~7688 This invention relates to the press sections of a paper machine, and in particular ln a so-called compact press section, which comprises a compact press roll combination whose rolls form two or more press nips with each other, the web running between the said nips. More particularly the invention relates to a method and frame construction which permits the fabrics in the press section and/or the press rolls can be conveniently replacPd .

In prior-art compact press sections of a paper machine, lu such as the applicant~s so-called Sym-Press~TM) press section, above the press rolls, both at the service side and at the operating side of the paper machine, there have been horizontal beams which connect the front frame and the rear frame of the press section permanently together. In this connection, and so 1'; also in the following description, the front frame means the frame part that is placed, in the direction of running of the web, before the compact press roll combination, to which said front frame, e.g.

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l 307688 the suction roll of the press is fixed. In a corres-ponding way, the rear frame means the frame part placed after the press roll combination.
In connection with the prior-art frame parts of the said press sections, difficulties have occurred in relation to t~e ~eplacement both of the press fabrics and o the press rolls. These problems have increased with the increase in the widths of the paper machines, in particular owing to the fact that the press rolls 1 o have become ever longer and heavier. ~ problems a~rava fe,l have~_~3~-~t6_paL~_ also been L~e~er~ by the fact that press abrics,which are made of plastic materials and which are rigid in the transverse direction,have started being used ever inc~easingly, which said press sq~e~3~ ~
abrics cannot be ~ed into a bundle, because they would be thereby wrinkled and become unusable.
Beloit Corporation has attempted to solve the problems described above by means oE a so-called "Elip-top" ~trade mark oE Beloit Corporation) frame construc-~ion. In this prior-art ~rame solution ~or a press section, such a -top frame is used as is provided wlth a pivot shaEt parallel to the transverse direction of the paper machine and placed above the press rolls, whereby ei~her the top part of the ront frame or the top part of the rear Erame can be opened around the said pivot shaft. The said two top parts of the Erame cannot be opened at the same time. By opening the said top part of the front frame, it is possible to faci-litate the replacement of the pick-up fabric o the press section and the replacement of the fabric that usually acts as the press fabric in the irst nip and in the second nip. Thereat, the top part of the rear frame is locked as a rame part on wllose support the opening-du~ping of the top part of the front frame takes place. Correspondingly, when the top part of the front frame is in the closed-locked position, the ' top part of the rear frame c~n be dumped so that the t 3~7688 press Eabric of the third press nip can be replaced.
The lower fabric of the first nip, which runs mainly in the basement space, is replaced by means of arrange-ments in themselves known.
The above "Flip-top" solution can be charac-te~iæed as a ~ort of a "drawbridge" which is opened around an ar-ticulated joint placed at the middle of the bridge, and only one half of the bridge at a time.
It is a drawback of the "Flip-top" solution 10 that, as -the ~aid articulated joint is placed right above the compact press roll arrangement, the solution hardly facilitates the replacement of the press rolls, but the rolls must be replaced in the prior-art way by shiting them to the side in the axial direction and by 15 from time to time changing the grasping point of the supporting hooks oE the crane, which is usually the traverse crane of the paper machine hall. By "edging"
in this prior-~rt way, the press rolls must be shifted over their entire length aside ~o the service side of 20 the paper machine, whicl1 also results in the drawback that the width o the aisle at the service side must be at least equal to the length oE the rolls of the paper mach:LIle, i.e. a total of a~out 8 to 10 metres, even though such a wide space at the service side would not ZS be necessary otherwise. In view of reducing the cost of construction of a paper machine hall, it would be highly valuable if the width dimension of the hall required by the paper machine could be reduced.
It is a further drawback of the "Flip-top"
30 solution referred to above, in view of the replacement of felts or equivalent, that, by means of one opening of the Erame, only one felt can be replaced at a time, J whereupon the said top part of the ~rame part must be locked into the closed position, and the other top part 35 of the Erame part can be dumped into the open position only thereinafter. The consequence is that, by means of the prior-art solution, tl1e replacement of the felts .

-:, - : ' -` 1 3076~8 and so also the replacement of the rolls takes a relatively long time, which lncreases the l~ngth of the standstills of the paper machine and, thus~ reduces the effective production time of the machine~

In connection with the replacement of felts and rolls, IJ with the prior art solutions, the standstill times have also been increased by the fact that it has been necessary to change the grasping point of the crane several times in connection with the replacement of a fabric or roll.

:I.u In the prior art methods and in connection with the prior-art frame constructions, the replacement of felts and rolls has been made difficult and slow by the circumstance that a 1~; "

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`` I 3Q76~8 sufficiently large free space has not been available for the r0placement operatlons. In particular above the rolls in the press section, whereby it has been necessary to work in very scarcP space, which increases the working time and reduces the safety at work.

It is an ob;ect of the present 1nvention to alleviate the above drawbacks and to provide such improvements in the prior-art frame construction of press sections and in the methods for the re.placement of fabrics and press rolls so that the replacement of fabrics and, above all, -the replacement of press rolls is more rapid and easier that in prior art.

According to the present invention there is provided a method for replacing one or more rolls and/or press fabrics in a paper machine press section, in particular in a so-called compact J press section, which comprises a compact press roll combination which rolls form two or more press nips with each other, the upper web running between the said nips, and which said press section comprises, in the direction of running of the paper web, a front frame placed before the said roll combination and a rear frame placed after the said roll combination, sald method comprising: providing an open space abova the said roll 2~

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combination between the front frame and rear frames by pivoting, relative to the front and rear frames, at leas-t two intermediate frame arrangements from a closed position into an open position;
and replacing a fabric and/or one or more rolls of the press roll combination through said open space~

The invention also provides in a compact press section of a paper machine, which said press section comprises a compact press roll arrangement whose press rolls form at least two press nips for a paper web~ the improvement wherein the press section comprises, in the direction of running of the web, a front frame :I.u placed ahead of said roll arranyement and a rear frame separate from said front frame, and at least two intermediate frame arrangements abcve said roll arrangement, and said intermediate frame arrangements being pivotally mounted relative to said front and/or rear frames between a closed positlon and an open position l~; to open a space above sald press roll arrangement through which the press rolls and/or press fabrics can be replaced.

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In a preferred embodiment of the frame con-struction in accordance with the invent~on, an auxiliary frame is used at -the top portion of the front frame, which au~iliary frame is permanently fixed or, preferably at its middle, linked by means of a pivot shaft transverse to the paper machine so as to be dumped into the open position, as a rule, in the opposite direction as com-pared with the said inter~lediate frame, in particular in order to facilitate the replacement of the pick-up felt. In -this embodiment of the invention, the top portion of the frame construction resembles a "draw-bridge construction" which is opened around pivot shafts placed at opposite sides of the "bridge flaps", as compared with each other, so that a larger free space is obtained above the frame construction of the press SeCtiGn in view of replacement of the press rolls and possibly also of the pick-up roll and of the fabrics.
In the following, the invention will be described in detail with reference to certain ex~mpli-fying embodiments of the invention, illustrated in the figures of the drawing, the invention being not con-fined to the details of the said embodiments.
Figure 1 is a schematical side vlew of the press section of a paper machine making use of the method in accordance with the invention, whlch said press section is provided with a frame constructlon in accordance with the invention.
Figure 2 shows a section at A-A in Fig. 1.
Figure 3 shows a section at s-B in Fig. 1.
Figure 4 illustrates the replacement of rolls, in particular of press rolls, in a press section in accordance with Figures 1, 2 and 3.
Figure 5 illustrates the replacement o pick-up and press L lts in the press section in a way correspol1dinc3 to Fig. 4.

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8 1 3()7688 Figure 6 shows such a front frame as is pro-vided with pivoting levers and actuating means by which the tensionlng roll for the pic~-up roll can be shifted in connection with the replacement of the felt to its parking site.
Figure 7 shows such an embodiment of the invention in which the intermediate frame conslsts of two parts, namely intermediate front frame and lnter-mediate rear frame.
The press section shown in Fig. 1 as a schematical side view comprises a closed press roll combinatiol1 13,16,21,31, which said press rolls form tl1ree subsequel1t nips N1,N2 and N3 between the rolls.
Moreover, the press section includes a fourth, separate 15 nip N~, wl1icl1 is formed between the press rolls 33 and 43. The press section comprises a first fabric 10 and a second fabric 20 ~usually felts), which two fabrics run through the first nip N1 and oE which the first Eabric 10 acts as a pick-up fabric and, moreover, as a 20 press Eabric in t~e second nip N2. The third press ~abric 30 runs through the third nip N3, and the fourth press ~abric 40, whic11 is a lower press fabric, acts as a press abric in the fourth nip N4.
Inside the loop o the first fabric 10, there 25 is a pick-up roll 11 provided with a suction zone 11a, which said roll transfers the web from the forming fabric 27 onto the run between the rolls 11 and 13. The fabric 10 i5 guidecl by guide rolls 12, of which the roll 12a is a tensioning roll. The second fabric 20 30 runs as guided by guide rolls 22. Correspondlngly, the third fabric 30 is guided b~ guide rolls 32, of which the roll 32a is a tensioning roll, and the roll 32b is J attached to the frame portion 80, and the guide rolls 32c and 32d are attached to a pivotable intermediate 35 frame G0, to be described in mor~ detail later. The fourth fabric 40, which shifts the web W from the polnt facing the transfer roll 18 into the last nip N~, runs .~

as guided by suction-transfer rolls 41 and 42 as well as by guide rolls 42'.

The passage of the web W beginning from the piclc-up point P is the following. The suction s2ctor 5 11a of the pick-up roll 11 detaches the web W from the wire 27 and ~ttaches it onto the bottom face of the fabric 1~, where the web W passes through the twin-fabric nip N1. The lower roll 21 of the nip N1 is pro-vided with a hollow face 21'. After the nip N1, the web W follows the first fabric, by the effect of the suction sector 13a of the suction roll 13. In the second nip N2, the web W is transferred onto the face of the smooth-faced 16' centre roll 16 and further into the tl1irc1 nip N3, after which the web W follows along with the centre roll 16 and, ~eing suided by the trans-fer roll 18, passes onto the Eabric 40 within the sucti.on sector o tl1e suction roll 41 and Eurther onto the other suction roll ~2 as well as further, being suppoxtecl by ~he fabric ~0, into the last nip N~.

~fter the n:Lp N~, ~he web W Eollows alorlg with the smootl1-Eaced press xoll 33, Erom which it is trans-Eerred on~o tl-e guic1e roll 46 and onto the single-draw abric ~ oE the drying sec~ion, which is guided by guide rolls ~9. The web W is shifted as a single-fabric draw into tl1e dryincJ section, o which twoupper cylinders 47 and two lower cylinders 48 are seen in Fig. 1.

The construction and operation of the press : section described above are primarily known in prior art, and they are described in this connection only in order to provlde background information and to faclll-~ tate the understanding of the invention.

~ ~ The method and the frame portion in accorance wlth the invention can also be used ln such a press section in which, in connectlon with a compact pressroll arrangement, the web also has open draws. The ~ different press rolls may also be att~ched and fitted .~ :

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~o 1 3076~8 in a way different from that shown in the figures.
The frame construction of a press section in accordance with the invention includes a front frame 50, onto whose top portion an auxiliary frame 51 pivotable by means of horizontal articulated joints 52 is linked, the guide rolls 12a and 12b of the flrst fabric 10 being mounted on the said auxiliary frame 51, of which rolls the roll 12a is attached to a tensioning device 54 for the purpose of tensioning the fabric 10. The tensioning movement of the tensioning roll 12a takes place towards the forming section. The front frame 50 is provided with openable intermediate pieces 55 for the replacement of the first fabric 10. In Fig. 1, tlle auxiLiary rame 51 is shown in the normal operating position, in which the frame part 51 is downwardly slant-ing in the direction of running of the web W, or hori-zontal, and the frame part 51 is, at one end, attached to the front frame 50 by means of a joint 53. In the way seen in Fi~ e joint S3 consists of 1anges 53a and 53b placed one against the other and attached to each other, e~g., ~y means oE eyebolts.
The suction roll 13 ol: the press is attached to the ront Erame 50 by means o horizontal pivot shaEts S by ~he interlllediate oE an intermediate rame 14. The lower roll 21 o the Eirst nip N1 is attac~ed to an intermediate frame 23, which is attached to the lower frame 26 by means of pivot shafts 25. The first nip N1 can be loaded by means of power units 24 fitted between the intermediate frame 23 and the lower rame 26. The second nip N2 is loaded by means of power units fitted between the intermediate frame 14 and the front frame 50.
The frame part in accordance with the in-vention lncludes a rear frame 70, whose front side ls provided with projecting parts 71, to whlch an lnter-mediate frame 60 is attached by means of horlzontal pivot shafts 62, which said intermediate frame 60 is .

076~8 placed above the compact roll arrangement 13,16,21,31.
By means oE the intermediate frame 60, the front frame 50 and the rear frame 70 are connected to each other so as to make a sufficiently rigid unit, e.g., in view of vibxation phenomena. ~t the front end oE the inter-mediate frame 60, there is an intermediate piece 65, which can be attached,at one of its ends, to the front frame 50, e.g., by means of eyebolts and, at the other end, to the end of the intermediate frame 60, e.g., by means of eyebolts, both of which said bolt joints can be opened relatively rapidly.
The centre roll 16 of the press is journalled stationarily on a frame part 19 oE its own, which is placed between the Erame part 26 of the roll 21 and the rear frame 70. The hollow-faced 31' press roll 31 of the third nip N3 is journalled on the loading arms 67, wllich are seen in Fig. 1 as illustrated by means of brolcen lines. ~rhe intermecliate frame 67 is, by means of pivo~ sha~ts 69, attached to the inter-medlate rame 60, whose pivot shafts 62 are, e.~., at the same posltion as ~he said pivot shafts 69 oE the intermediate Erame 67 of the roll 31. The intermediate Er~me 67 of the roll 31 can be pivoted relati~e the intermediate Er~me 60 by means of power units 6U, by means of which the nip N3 between the rolls 31 ~nd 16 can also be loaded.
For the purpose of opening of the inter-mediate frame 60, taking place around the pivot shafts 62, the side beams 61 of the lntermediate frame 60 are connected with arms 64, which are again connected with actuating means 64a related to the rear frame 70.
After the rear side of the rear frame 70, there ~s a frame part 38, to which the transfer suction roll 42 as well as the lower roll 43 of -the fourth press nip N4 are attached. The press roll 43 is fitted to an intermediate Erame 35, which is pivotable around a pivot shaft 36 by means of power units 37. The upper -roll 33 of the fourth nip N4 is journalled stationarlly onto the frame part 39, in whose connection the guide rolls 46 and 49 as well as the irst drying cylinder s 47 or the corresponding so-called lead-in cylinder are also jo~rnalled. ~bove the frame part 39, there is an upper frame 80, on which the guide roll 32b of the third fabric 30 as well as the tensioning roll 32a of the fabric 30, supported on a tensioning device 81 that can be displaced, are mounted stationarily. Moreover, in connection with the top side of the frame part 80, there are reconditioning devices (not shownl for the fabric 30.
~s is shown in Figures 1 and 2, the operation-sicle and service-side sides of the front frame 50, of the aux.iliary frame 51, and o~ the lower frame are con-nected together by cantilever beams 110, 111 and 114, which are at one end supported by means of traction members l20 on the lower beam 112. Fig. 2 shows the horlzontal pivot shats S2 o the auxiliary frame 51 20 above the Exont ~rame 50 as well as the journalling ~langes SG o the said pivot sha~ts 52. The foundation of the paper machine building is denoted with reference numeral 500 and the floor plane with reference numeral `S01. In Figures 2 and 3, the operating side of the 25 paper macl1ine is denoted witl1 reference letter K and the service side with reference letter 1l.
Fig. 4 illustrates the replacemen-t of rolls taking place in accordance with the method of the in-vention. In accordance with Fig. 4, the auxiliary frame 51 above the front frame 50 has been plvoted around the pivot shafts 52 into the open position 51' by opening the jolnt 53. Before a roll or rolls are J replaced, the fabric inside whlch the roll concerned is has been removed. In accordance with Fig. 4, lifting 35 ropes 95 have been attached to the axle journals of the suction roll 11', which said lifting ropes 9S are also attached to the lifting hooks 90 of the traverse crane.

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The pick~up roll is replaced in the ways known in prior art.
Before the press rolls 13, 16 and 21 a.re lifted, the intermediate pieces 65 of the intermediate frame 60 o~ the press have been detached and the inter-mediate frame 60 has been pivoted to the vertical open position 60', in which position the side beams 61 of the intermediate frame are in the position 61'. The pivoting of ~he intermediate frame 60 takes place by means of the rods 64 and the scxew motors 64a around the pivot shafts 62. Thereby, a space T open at the top is opened, th~ough which space the lifting of the said press rolls 13, 21 and 16 can be performed.
The suction roll 13 of the compact press section is suspended on liting lines 96, which are attached to the lifting hook 91. The suction roll 13 is lifted straight upwards as so-called centre lifting and shiE~ed to the side oE the press section while at the satne time t~rning it in the space. After this, in the same way, the lower roll 23 of ~he first nip N1 caIl be liÇted by means of li.Eting lines 96'. The suction roll 13 may be liEted either by its axle jour-nals by means of two liEtiIlg ropes or AS so-called centre lifting by means oE lifting lines.
When the intermediate frame 60 is in the opened position 60', the press roll 31 oE the third nip N3 can also be replaced as centre lifting by means of lifting ropes or lines 98 by uslng a lifting hook or hooks 93. ~efore this, if necessary, the roll 32a can be shifted to the parking site 32a'.
~ ter the third fabric 30 has been removed or the roll 32a has been shifted to the position 32a', a fre0 space T1 is opened above the fourth nip N4, which space is open from above so that the pr~ss rolls 33 and 43 can also be lifted as centre lifting. In accordance with Fig. 4, the press roll 33 is lifted by means of lifting lines 99 attached to the lifting hooks 94, and `' '' ' ` ' ', ,' .

, the lower roll 43 by means o lifting lines 99'.
By the centre lifting described above, it is meant that the roll is suspended on one crane hook only as supported by li~ting lines, which lines support the roll in a downwardly open V-~orm syn~netrically at both sides oE their vertical centre plane. This centre lifting has the advantage that the roll can be pivoted in the horizontal plane around its vertical centre axis, which usually facilitates the shifting of the rolls even in more congested premises. In the case of lifting of the roll by the axle journals, the roll can usually be shifted only so that it maintains its longitudinal direction, because the operation o two cranes in cooperation is difficult and dangerous in view of the saEety at work.
Above, in Fi~. 4, the operations for replace-ment or servicing have been described in respect of ; all oE the r.olls l1,l3,21,3l,33,~3. In practice, how-ever, as a rule, only one roll requiring replacement or servicing is liEted at a ti.me, whereby only the necessary number oE fabr:Lcs are removed and the neces-sary Erame par~s are opened.
Fig. S ill~strates the replacement of all of the di~erent fabrics 10,20,30 and 40, which is not always per~ormed at one time. For the replacement of ~he irst fabric 10, the auxiliary frame 51 of the front frame S0 has been pivoted around the pivot shaft 52 to the open position 51', or, if the auxiliary frame S1 i.s permanently fixed, it is only cantilevered, and the tensioning roll 1~a, placed as supported on the parts 54 of the auxiliary frame S1, has been shifted to the parking site 12a' along the route indicated by the `~ ~ arrow a1. In connection with the replacement of the fabrlc 30, the intermediate frame 60 I~ pivoted to the opened posltion 60', whereby the open space T descrlbed above is formed so as to facilitate the replacement of the fabric as well.

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1 ~07688 In connection with the replacement of the ~irst fabric 10, the intermediate pieces 55 at the service side o the front frame 50 are opened so that open gaps V are formed in the frame, through which gaps the felt loop 10' can be passed. The suction roll is shifted into the posit~on 13' and the press roll 21 into the lower position 21', and the intermediate pieces 25 of tlle frame 26 are opened in connection with the replacement of the second fabric 20.
In connection with the replacement of the third fabric 30, the intermediate pieces 72 and 73 are opened and the tensioning roll 32a is shifted along the route a2 to the parking site 32a' located above the rear frame 70. The intermediate frame 60 has been pivoted into the inner position 60', whereby, along with it, the press roll 31 and the guide rolls 32c and 32d are also pivoted into the inner positions 32c' and 32d'.
~n connection with the replacement o the lower fabric ~0 of the ourth nip N4, the intermediate pleces 72,7~,75 and 45 as well ~s the nip N4 are opened, whereby the replacement o the ~ourth abric 40 may possibly take place through the space ~r1 open at the top.
The roll oE felt ~00 ls pushed along a rail ; 25 (not shown) placed in the space between the int~r-mediate pieces 72 and 74 of the machlne.
As ls shown in ~'ig. S, the roll 100 of the first fabric, supported on a pole carried by lifting wires 10l has been brought to the side of the service side of the paper machine, and from the roll 100 a loop 10' has been unwound, wl1ich loop is passed through the spaces V and through the opened nips N1 and N2 to its operating position around the cantilever beam 111, whereupon the roll 12a' is shifted to its operating position and the auxiliary frame 51' is pivoted into the closed position and its joints ~3 are fastened.

-When the second fabric 20 is being replaced, the roll 200 of the second fabric is brought, by means of a pole carrled by wires 201, to the side of the paper machiner whereupon the loop 20' unwound from the roll 200 is passed through the opened spaces V and through the opened first nip ~1 to its operating posi-tion around the cantilever beams. Before this, those tensioning and guide rolls of the fabric 20 that are placed in the basement space below the loor level 501 have ~een shif~ed to the upper position below ~he roll 21 up to the level of the cantilever beams 114, e.g~, by means of arrangements and devices similar to those described in the applicant's Finnish Patent ~pplication No. 803020. Ilereupon, the pole supporting the roll 200 is shiEted on its carrying wires 201 towards the space T in the position shown in Fig. 5, whereby the second Eabric 20 becomes positioned in its operatlng position around the cantilever beams 114 when the nip N2 is opened to a suEficient extent.
The replacement oE the third fabric 30 is carried ou~ by unwlnding a loop 30' from the roll 300 placed on a pole carried by wires 301 and by passiny the said loop through the spaces V to around the various rolls 31,32c',32d',32a' placed around the cantilever beams 113.
The replacement of the fourth fabric 40 is carried out in a way similar to the replacement of the fabric 20 so that, when the fourth nip N4 is in the opened position, a loop 40' of abric 15 passed from the roll 400 ca~rled by wires 401 to around the cantl-lever beams 11S in the way sho~n in Fig. S.
In the ollowing, the operations to be carried out in connection with the replacement of different felts and different rolls will be listed in detail.

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Operations for the replacement of felt:

Pick~up felt 10 - the press section and the wire part are stopped;
the rolls 11, 13 ~nd 2 1 are lockcd ~n the open p~sition, - the old felt 10 is removed by means of a pin roll : and a hydraulic motor, - the tensioning roll 12a is shifted to its parking site (position 12a'), - the eyebolts of the auxiliary frame are opened at the service side and operating side, i.e. the joints 53 are opened, - the auxiliary rame 51 is pivoted to the upper position 51' by me~ns oE actuating means ~not shown), - the eyebolts of the intermediate pieces 55 are opened at the service side, and the group is canti-levered by mearls of hydraulic cylinders and the intermediate yieces ~5,6S are removed, whereby the spaces V Eor the insertion of tlle felt 10 are made i free, - the eyebolts o the 2nd press and of the pick-up frame are opened and the frame is cantilevered by mean9 oE the hydraulic cylinders.of the service side, and ~he intermediate pieces S5 are removed, - the felt roll 100 is suspended on the crane 101, and a necessary felt loop 101 is unwound for insertion, - the felt loop 101 is driven in wlthout cllanging the grasping points, - the intermediate pieces 55 are installed into their positions, - the auxiliary Erame 5 is pivoted down and locked, - the tensioning roll 12a' ls lifted back onto the 35 - tensioner 54.

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Felt 30 of the 3rd press - the press section and the irst drying group are stopped, 5 - the Sym-roll 31 of the 3rd press i~ raised to the upper position by pivotiny the intermediate frame 60 to the open and upper position 60', - the old felt is removed, - the tensioning roll 32a is shifted to the parking position 32a', - the eyebolts of the press frame are opened from the service side and operating side, - the frame is cantilevered by means of hydraulic cylinders, and the intermediate pieces 72 and 73 are removed, - paths of passage are opened for the felt through the service bridges, - the new elt roll 300 is suspended on the crane 301, and a necessary Eelt loop 301 is unwound for insertion, - the felt loop 301 is driven in without changing the gxasping points oE the crane, - the intermediate pieces 72 and 73 are installed in their positions, the intermediate frame 60 is pivoted down, - the tensioning roll 32A I iS lifted back onto the - ten~ioner 81.

Operations for the replacement of rolls:
- the machine is stopped and the roll and/or rolls 11,13,~1,31,33 are locked in the open position, - the intermediate frame 60 is pivoted up into the position 60' for ttie replacement o~f the Sym-roll 31, : 35 - the rock roll 16 can be replaced by centre lifting through the top, ` `~

- the suction roll 13 of the 2nd press is replaced, after opening of the intermediate frame 60, by floating and by, at the same time, turning it straight ~o the service side without changing the grasp point;
- the Sym-roll 21 of tl1e 1st press and the pick-up roll 11 are replaced in a way known ln prior art. If the suction roll can be pivoted out of the way, the Sym-roll 21 can be lifted straight upwards.

In the way described above, the fabrics 10,20, 30 and 40 can be replaced more advantageously than in prior art so that, in connection with the replacement of the fabrics, there is an adequate space available for tlle various operations, above all because the frame parts in accordance with the invention can be opened to a position also favourable for replacement of fabrics.
As comes out from Fig. 5, it is partly owing to the metllQd and the frame part in accordance with the invention that the rolls to be placed inside the Eabrics ~o be replacecl can be placed in a very small space and close to each other, whereby the free loop to be ùnwound o~ th~ roll o~ fabric and to be itted around the various rolls and cantilever beams can be made relatively little and preferably substantially drop-shaped, which ~acilitates and simplifies the work of insertion. In respeot of the replacement of the ~abrics, the method in accordance with the invention is also excellently suitable in the case of fabrics made of plastic, which cannot be wrinkled to a bundle in the lateral direction.
Fig. 6 shows such a front frame in accordance with the invention as is provided with pivot lavers and actuating means, by means of which the tensioning ro1l of the plck-up felt can be shifted to lts parking site.
Fig. 6 shows such a preferred variatlon of the inventlon disclosed in the present application in which the front frame 50 is provlded witl1 an auxlliary frame 51 slmllar ..

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to that described in the application, which said auxiliary rame 51 is attached to the front frame 50 by means of hori.zontal pivot shafts 52. According to Fig. 6, the equlpment of replacement of the pick-up felt 10 has been modified, relative that described above, so that, as the means o replacement of the tensioning roll 12 for the pick-up felt 10, it is not necessary to use the cranes of the hall, but the front frame 50 is provided with particular replacement devices of its own. These replacement devices inclufle a pair of pivot levers 150, which said levers are placed at both sides of the front frame 50. The pivot levers 150 are linked to the front frame 50 by means of horizontal shafts 151. The pivot levers 150 consist of angular levers, whose arm portions 150a areconnected to actua-ting means. The said actuatlng means consist of hydraulic cylinders 152, which are, at the lower end, connected to the fro.nt frame 50 by means oE pivot shafts 153 and whose piston rods 154, or extension parts connected to same, are connected to the arm portions 150a oE the pivot levers 150 by means of articulated joints 155. At the top ends of the pivot levers 150, there are devices b~ means oE which the tens.ioning rol.l 12a to be replaced cnn be attached onto the pivot levers 150. rhese attaching devlces include l.ocking jaws 156, which are attached to the top ends o the pivot lcvers 150 by means of arti-culated joints 157.
In Fig. 6, when the tensioning roll l2a is to be replaced, having been detached from its bearing blocks, it is attached, by means o the locking jaws 157, to the top ends of the pivot levers 150 and, by means of the hydraulic cylinders 152, the levers 150 are pivoted to the lower positlonO ~hereby, the tensloning roll 12a is shifted along ~he route L to its parking site 12a' placed in connection with the top side of the frame 50, with the purpose explained -, .

above. When, after replacement of the pick-up felt 10, the tensioning roll 12a is shifted from its parking site back onto the tensionlng means 54 placed in con-nection with the auxiliary frame 51, the said pivot S levers 150 are used in the reversed sequence, as COIII-pared with the above description. When the pivot levers 150 axe not needed, they are pivoted into such an inwardly position in which they do not obstruct other devices or operations. Fig. 6 shows the actuating means 59 by which the auxiliary frame 51 can be pivoted in the way described above. Fig. 6 also shows the extreme upper position 12a" of the tensioning roll 12a.
Fig. 7 shows a preferred embodiment of the invention in WlliCIl the intermediate frame 60 CollSiSts of two parts, viz. an intermediate front frame 60a, which is linked to the front frame 50 by means of hori-zontal articulated joints 62a. The intermediate front frame 60a can be pivoted around the said horiæontal shafts 62a by means o~ actuatin~ means 64a'. The inter-mediate front Erame 60a consists of substantially V- or L-shaped side components, which are attached to the intexmediat~ par~ 60c oE the lntermediate frame 60 by their ~nd opposite to th~ir linkage 62a by means of a connecting part 65a, the said intermediate part 60c 2S being again attached to the bearing housings 17 of the centre roll 16 of the press. The intermediate-frame parts 14, to whicll the suction roll 13 of the press is journalled, are attached to the intermediate ~ront frame 60a by means of horizontal articulated joints 15.
The intermediate frame parts 14 can be plvoted relative the intermediate front frame 60a by means of power units 14a, by means of which the nips N1 and N2 can be loaded, at least partly.
As is shown in Fig. 7, the intermedlate frame 60 includes a second intermediate frame component, namely the intermediate rear frame 60b, whlch ls attached to the rear Erame 70 by means of horizontal joints 62b :

22 1 3~ 1 688 so as to be opened and closed by means of actuating means 64b, for the purposes explained above. The press roll 31, which forms the third pxess nlp N3 with the centre roll 16, is journalled on the intermediate rear frame 60b by the intermediate of the frame part 67b.
The press roll 31 can be shift~d to tl1e open position 31' relative the intermediate rear frame 60b by using power units 68b, by means of which said power units the nip N3 can also be loaded. Viewed from the side, the side beams of the intermediate rear frame 60b are substantially U-shaped, and they are, by their ends opposite to their linkage 62b, attached to the said stationary intermediate part 60c of the inter-mediate frame 60 by means of the connecting part 65b when the intermediate frame 6Oa, 6Ob is in the closed positio~1.
The intermediate rame described above and illustrated in Fig. 7, which con~ists of two frame parts 60a and 60b as well as of a statlonary part 60c connect-ing them, is opened and çlosed for the purpose describedabove. In other re~pects, the construction shown i ~ig. 7 i8 ~qual to t;he above .
Above, the invention has been described wlth re~erence to the construction of such a press section in which the biggest problems are experienced in the reylacement o~ rolls and in particular of fabrics, i.e.
the press section has a maximum number oE press rolls and a maximum number of abrics. The solution of the invention can also be applied to press sections of other sorts, e.g. to the applicant's Sym-Press I and Sym-Press II (trade marks~ press sections, of which the former has only two nips, i.e. the nips N1 and N2, ` ~ and no separate nip N4 at all, and the latter has ; three nips N1, N2 and N3 and no separate nip N4. In such a case, either the third and the iourth fabric or the Eourth fabric are omitted.
The scope of the invention also includes such em~c-~liments in which, e.~3., the suction roll 13 .

1 30768~

is arranged on stat.ionary bearing supports and tlle centre roll 1G is fitted on support arms for the p~lrpose of loading and/or opening of the nips.
In tlle case oE low-speed paper machines, in which no particularly high requiremel1ts are imposed on the ri~idity of the ~rame o~ the press section, such a frame part is possible in wi1ich the openable lnter-mediate part 65 has been omitted entirely, whereby the press section is naturally open at the top at the first, second, and third, if any, nips, which ln itselE faci-litates the replacement o the press rolls and press fabrics. Such a construction is, however, not possible in the case of high-speed paper machines, in which the problems of vibration and the rigidity of the frame require a connection between the front frame 50 and the rear frame 70, which has, in prior art, taken place by means of permanently ixecl horizontal frame beams, to which the upper press roll of the third nip is usually attached.
~l~erna~ive:Ly, tlle auxiliary frame 51 may a.lso be incLined, by means of a canti.lever beam 110, in the tral1svers~ direction o~ the machlne ~by r~ising the service side upwards~ as supported on articulated joints placed nt the opel.atlllg side, whereby the posi-tion S1' is not required in order to produce tl1e space V at the service side between the frame 50 and the auxlliary frame 51.
Many other varlations are also possible within the scope of the inventive idea.
In the ollowing, the patent claims will be given, whereat the various details oE the invention may show variation within the scope of the inventive ldea defined in the said claims.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A method for replacing one or more rolls and/or press fabrics in a paper machine press section, in particular in a so-called compact press section, which comprises a compact press roll combination whose rolls form two or more press nips with each other, the paper web running between the said nips, and which said press section comprises, in the direction of running of the paper web, a front frame placed before the said roll combination and a rear frame placed after the said roll combination, said method comprising:
providing an open space above the said roll combination between the front frame and rear frames by pivoting, relative to the front and rear frames, at least two intermediate frame arrangements from a closed position into an open position;
and replacing a fabric and/or one or more rolls of the press roll combination through said open space.

2. A method as claimed in claim 1, wherein said front and rear frames are rigidly connected together at least in part by said intermediate frame arrangements when they are in the closed position.

3. A method as claimed in claim 1, wherein said intermediate frame arrangements have respective press rolls carried thereby, and when said intermediate frame arrangements are in the closed position, said front and rear frames are bridged by said intermediate frame arrangements, the press rolls carried thereby, and a centre roll which forms press nips with said press rolls.

4. A method as claimed in claim 2, wherein said intermediate frame arrangements are connected together through a fixed intermediate part.

5. A method as claimed in claim 1, wherein said fabric is a pick-up press fabric and/or an upper fabric.

6. A method as claimed in claim 1, wherein said intermediate frame arrangements are articulated respectively to said front and rear frames.

7. A method as claimed in claim 1, wherein said intermediate frame arrangements are horizontally articulated to said front and rear frames.

8. A method as claimed in claim 1, wherein at least one of a centre roll and suction roll in said press roll combination is replaced by means of so-called centre lifting by first shifting the roll towards the service side of the paper machine in the axial direction of the roll and, making use of the said open space, by gradually turning the roll to be replaced so that it becomes parallel to the machine, which operation takes place while one end of the roll is inside the open space in the frame of the press section.

9. A method as claimed in anyone of claims 1 to 8, wherein, in order to replace an upper press fabric, the roll of a said press nip associated with said upper press fabric is pivoted to its retracted position, guide rolls for the fabric loop to be replaced are pivoted to their retracted positions, a tensioning roll associated with said upper press fabric is shifted to a temporary parking site on the associated front or rear frame, the press fabric is laterally withdrawn through gaps opened in the side of the associated front or rear frame, a new fabric loop is unwound from a roll of new fabric, which is placed on a pole suspended on a crane, by one grasp of the crane and inserted into the press section, said gaps are closed, said tensioning roll is returned to its normal position, and said intermediate frame arrangements are closed.

10. A method as claimed in anyone of claims 1 to 8, wherein, in order to replace a lower press fabric, the roll of a said press nip associated with said lower press fabric is pivoted to its retracted position, a tensioning roll and guide rolls for the fabric loop to be replaced are pivoted to their retracted positions, the press fabric is laterally withdrawn through gaps opened in the side of the associated front or rear frame, a new fabric loop is unwound from a roll of new fabric, which is placed on a pole suspended on a crane, by one grasp of the crane and inserted into the press section, said gaps are closed, and said tensioning roll is returned to its normal position.

11. In a compact press section of a paper machine, which said press section comprises a compact press roll arrangement whose press rolls form at least two press nips for a paper web, the improvement wherein the press section comprises, in the direction of running of the web, a front frame placed ahead of said roll arrangement and a rear frame separate from said front frame, and at least two intermediate frame arrangements above said roll arrangement, and said intermediate frame arrangements being pivotally mounted relative to said front and/or rear frames between a closed position and an open position to open a space above said press roll arrangement through which the press rolls and/or press fabrics can be replaced.

12. A compact press section as claimed in claim 11, further comprising actuating means for pivoting said intermediate frame arrangements into the open position.

13. A compact press section as claimed in claim 11 or 12, wherein, in the closed position, the free ends of said intermediate frame arrangements are rigidly interconnected by a fixed intermediate part.

14. A compact press section as claimed in claim 11 or 12, wherein said intermediate frame arrangements have respective press rolls carried thereby, a centre roll is mounted between said front and rear frames, and said respective press rolls carried by said intermediate frame arrangements form press nips with said centre roll when said intermediate frames are in the closed position, said intermediate frame arrangements, the press rolls carried thereby, and said centre roll bridging the gap between said front and rear frames.

15. A compact press section as claimed in claim 11, wherein the upper roll of the first nip in the press section is provided on a further frame, which is pivotable about a pivot shaft transverse to the paper machine, the centre roll of the paper machine is journalled on a stationary frame part, and the press roll in the third nip of the paper machine, which roll is placed inside the loop of the third fabric, is carried by a said intermediate frame arrangement so as to be shifted to the open position therewith.

16. A compact press section as claimed in claim 15, wherein said stationary frame part is connected to said rear frame.

17. A compact press section as claimed in claim 11 or 12, wherein two or more guide rolls of the third fabric are journalled on said intermediate frame arrangement carrying said press roll, which said guide rolls can be shifted into their retracted positions as said intermediate frame is pivoted into its open position for the purpose of facilitating the replacement of the third fabric.

18. A compact press section as claimed in claim 11 or 12, wherein the press roll of the last nip in the compact press roll arrangement is journalled on a further intermediate frame arrangement that is pivoted to said intermediate frame arrangement mounted on said rear frame, and actuators are provided to shift said press roll relative to said intermediate frame mounted on said rear frame, said actuators also serving to load said press roll in the normal operating position.

19. A compact press section as claimed in claim 11, wherein an auxiliary frame is attached to the top portion of the front frame, which said auxiliary frame is linked by means of a pivot shaft transverse to the paper machine to the front frame so as to be pivoted to the upper position during replacement of the first fabric, a tensioning device for the first fabric is provided in association with said auxiliary frame, a tensioning roll supported on said tensioning device has a parking site on the front frame, and said auxiliary frame is, at its end next to the press section, lockable to the front frame in the normal operating position.

20. A compact press section as claimed in claim 19, wherein said front frame is provided with shifting means, by which the tensioning roll for the pick-up felt can be shifted from its normal operating position to its parking site to facilitate the replacement of the pick-up felt or the like.

21. A compact press section as claimed in claim 20, wherein said shifting means for the tensioning roll of the pick-up felt comprise pivot levers linked to said front frame, actuating means are provided to act on said pivot levers, and said pivot levers are provided with grasping means by means of which the tensioning roll can be attached to the pivot levers when the tensioning roll is shifted onto its parking site and from there back into its operating position.

22. A compact press section as claimed in claim 11, wherein each said intermediate frame arrangement has a press roll journalled thereto such that as said intermediate frame arrangements are pivoted to the open position their associated press rolls are moved out of their normal operating position and into their retracted positions.

23. A compact press section as claimed in claim 22, wherein in the normal operating position said press rolls journalled to the intermediate frame arrangements define press nips with a common central roll.

24. A compact press section as claimed in claim 23, wherein said common central roll is journalled on a stationary intermediate part.
25. A compact press section as claimed in anyone of claims 22 to 24, wherein said intermediate frame arrangements are interconnected in the normal operating position by rigid connecting means.