Background technology
In recent years, the high speed of paper machine obtains advancing, for to should the high speed process proposing a kind of paper machine of non-open draw, by the squeezing unit, the state that l Water Paper one is fixed on supported by press felt and waterproof conveyer belt and dry canvas (dry felt) etc. is walked down from forming unit.Owing to be not " open draw (オ one プ ソ De ロ one) ", promptly not " l Water Paper walks in airborne state under without any the free state that supports ", the suffered resistance from air of l Water Paper in the walking is suppressed to Min., even so when running up, also can fully suppress the generation of disconnected paper.
The paper machine of this non-open draw for example, has United States Patent (USP) 4,483, No. 745 communiques, 5,792, No. 320 communiques of United States Patent (USP), 5,951, No. 821 disclosed technology such as communique of United States Patent (USP).Fig. 3 be expression from above-mentioned U.S. Pat P5, the final side view that squeezes the formation pattern of first group of drying of 951, No. 821 communiques and 5,792, No. 320 disclosed paper machines of communique of United States Patent (USP).By the pressing device 101 pressurized and dehydration of the formed paper of not shown forming unit, be transported to final pressing device 102 then via upstream side.
Upside at final pressing device 102, for example, being wound on suction roll 102b and the upside pressure roller 102c by having the formed upside felt of absorptive felt 102a, downside at final pressing device 102, for example, being wound on by the formed impermeability conveyer belt of impermeability material 102d on downside roller 102e etc.
Like this, the l Water Paper 120 that transmits from upstream side pressing device 101 is attracted on suction roll 102b, and be attracted on the upside felt 102a, be transmitted and be directed to final pressing device 102 sides by this upside felt 102a, utilize the clamping of upside pressure roller 102c and downside pressure roller 102e to push the two sides and press water, this moisture is absorbed by upside felt 102a.
After final pressing device 102, be provided with drying device 103, be attracted on the suction roll 103b being placed on the l Water Paper 120 that sends on the impermeability conveyer belt 102d at drying device 103, and be adsorbed onto on the dry canvas 103a.The interior absorption box 104 of loop wire that utilization is arranged on canvas 103a makes absorption l Water Paper 120 by this canvas 103a, and is sent to first drying cylinder (De ラ イ ヤ シ リ ソ ダ) 103e simultaneously.Then, make l Water Paper 120 counter-rotating by reverse roll 103f after, send it to the second drying cylinder 103g, afterwards, be sent to same not shown reverse roll and drying cylinder again.In this transport process, by with dry canvas 103a l Water Paper 120 by being pressed in dry l Water Paper 120 on the drying cylinder.
L Water Paper 120 in the squeezing unit that comprises above-mentioned final pressing device 102 for dehydration when pressurized, its thickness will reduce, simultaneously (for example in the direction vertical with compression aspect, the direction of travel of l Water Paper 120) elongation slightly to some extent, this elongation all can produce when each pressurization, and produces accumulation on l Water Paper 120.So, more to the direction of travel downstream of l Water Paper 120, l Water Paper 120 extend just greatly more, cause tension force to reduce.
Therefore, the peripheral speed of suction roll 103b set the speed that sends from final pressing device 102 greater than l Water Paper 120, l Water Paper 120 is implemented so-called traction, to be absorbed in the elongation that final squeezing unit 102 is produced.
; above-mentioned paper machine as shown in Figure 3; the elongation (relaxing) that l Water Paper 120 on the dry canvas is produced; mainly contain following two kinds; the phase I elongation that dry canvas 103a produces when the first drying cylinder 103e peels off contacts the second stage elongation that drying cylinder (particularly second drying cylinder) produces when being heated with l Water Paper 120.Below, phase I elongation and second stage elongation are described respectively.
At first, about the phase I elongation, will mechanism that eliminate the moisture in the l Water Paper 120 at drying device 103 be described in the lump.
Stride the l Water Paper 120 that is placed on the suction roll 103b and sent to drying cylinder 103e, the 103g that is located at the downstream in proper order ..., and be pressed against these drying cylinders 103e, 103g respectively by dry canvas 103a ... outer peripheral face on.At this moment, each drying cylinder 103e, 103g ... periphery form very smoothly, so l Water Paper 120 is adhered to drying cylinder 103e, 103g by its surperficial moisture and paper powder and sticky object (below, moisture, paper powder and sticky object are referred to as " moisture etc. ") ... periphery on.
Like this, stick to l Water Paper 120 on the drying cylinder when the drying cylinder periphery is peeled off, the part of the moisture of wet paper surface etc. remains on the drying cylinder periphery.The part that is attached with water etc. of this drying cylinder, along with advancing of the running phase place of drying cylinder, before contacting l Water Paper 120, the water that this is accompanying etc. are scraped by wing etc. or are dried next time, and be eliminated from the periphery of drying cylinder, form and contact the preceding roughly the same surface state of l Water Paper.That is, the adhesion amount of water etc. and removing amount make the drying cylinder surface keep poised state about equally.Particularly, be attached with many water, paper powder and sticky object on the periphery of the first drying cylinder 103e, so l Water Paper 120 adheres to easily.
Therefore, at the first drying cylinder 103e, even l Water Paper 120 is through the pick-up point A of super-dry canvas 103a on the first drying cylinder 103e, be not dried canvas 103a by being pressed in the first drying cylinder 103e when going up, because this bonding force is greater than centrifugal force, so l Water Paper 120 still can move with the state on the periphery that sticks to the first drying cylinder 103e and this periphery one by shown in Fig. 3 dotted line.When the part of l Water Paper 120 moved with the state on the cylinder periphery of sticking to, the tension force of this part rose gradually, and soon, l Water Paper 120 is promptly peeled off from the first drying cylinder 103e, and this just forms above-mentioned phase I elongation.
As shown in Figure 3, near the above-mentioned pick-up point A of the first drying cylinder 103e, across dry canvas 103a, in the face of l Water Paper 120, be provided with pressure differential generation unit (for example drawing box) 105, by this pressure differential generation unit 105 l Water Paper 120 is adsorbed on the dry canvas 103a, suppresses l Water Paper 120 and adhere on the first drying cylinder 103e.
In addition, for auxiliary this pressure differential generation unit 105, at above-mentioned pick-up point A, in the face of the first drying cylinder 103e, be provided with stripping paper doctor unit 106 and air injection unit 106a, utilize the front end of stripping paper doctor unit 106 and the air that sprays from air injection unit 106a that the l Water Paper 120 that sticks on the cylinder periphery is peeled away.In addition, by making the periphery generation negative pressure that l Water Paper 120 is directed to the reverse roll 103f of the second drying cylinder 103g from the first drying cylinder 103e, make the l Water Paper 120 that is wound on the reverse roll 103f leave the roller periphery, thereby do not stick on the first drying cylinder 103e by centrifugal force.
But,, virtually completely can not suppress although this practice is to want to suppress the phase I elongation.
L Water Paper 120 is during through drying devices, and the intensification of l Water Paper 120 and degree of drying improve, and makes the viscosity of moisture of wet paper surface reduce thereupon, and the bur of wet paper surface is disappeared, and finally makes l Water Paper 120 reduce rapidly to the adhesion of drying cylinder periphery.Therefore, after second drying cylinder, sticking on the cylinder periphery with l Water Paper 120 is that the phase I elongation of cause is very little.
Below, the second stage elongation is described.L Water Paper 120 order sliding-contact drying cylinder 103e, 103g and walking, the temperature of l Water Paper 120 rises thereupon, because the expansion of the moisture that l Water Paper 120 is had makes l Water Paper 120 produce elongation.Generally, this elongation and the first drying cylinder 103e ratio take place greatlyyer later at the second drying cylinder 103g.This is because at the first drying cylinder 103e, l Water Paper 120 does not heat up as yet, and the moisture of l Water Paper 120 does not produce big expansion, and after the second drying cylinder 103g, l Water Paper 120 is heated up, due to contained moisture expands greatly in the l Water Paper 120.Like this, owing to the elongation that the expansion of original moisture produces l Water Paper 120, with respect to the above-mentioned phase I elongation that produces at the first drying cylinder 103e, the elongation that the second drying cylinder 103g in the downstream produces is many, so this elongation is called the second stage elongation.
Passing through the only moment of several drying cylinders, l Water Paper 120 produces above-mentioned phase I elongation and second stage elongation, and l Water Paper 120 presents relaxed state on dry canvas 103a.L Water Paper is pressed against on the drying cylinder in this state, and l Water Paper produces fold, and stress focuses on the chirring place of this fold, has strengthened the possibility that causes disconnected paper.
U.S. Pat P5,888, No. 354 communiques disclose the technology of the phase I elongation that suppresses above-mentioned drying unit.
What Fig. 4 represented is the part of this technology, this technology is not carried out open draw between the forming unit (omitting diagram) and the first drying cylinder 202a, draw l Water Paper 120 by setting speed difference in pressing device, thereby eliminate the elongation that adds the l Water Paper 120 that squeeze water produces owing to the pressing device that comprises final squeezing unit 201a etc.The felt 201c extension that final squeezing unit 201a adopts is set to the first drying cylinder 202a, is setting up dry canvas 202b at the second drying cylinder 202d and reverse roll 202c, can draw l Water Paper 120 thus between the first drying cylinder 202a and the second drying cylinder 202d.Therefore, can suppress the phase I elongation of the first drying cylinder 202a.
But in this technology, the elongation of l Water Paper 120 direction of travel that the maximum final squeezing unit 201 of dewatering pressure (clamp pressure) produces in constituting the squeezing unit of pressing device fails to decontrol in the downstream of retaining part.Therefore, on l Water Paper 120, produce trickle wrinkle, l Water Paper 120 is walked under the state of compression on the first drying cylinder 202a having.
Therefore, l Water Paper 120 in not by felt 201c and dry canvas 202b the either party by the some C, the D that are pressed on the first drying cylinder 202a between, particularly when paper machine fast turn-around, decontrol from l Water Paper 120 as the elongation that compression is pressed.As a result, as shown in phantom in Figure 4, l Water Paper 120 is peeled off from the periphery of the first drying cylinder 202a between above-mentioned some C, D, becomes lax greatly on the periphery of the first drying cylinder 202a.Between above-mentioned some C, D, l Water Paper 120 changes since position that the periphery of the first drying cylinder 202a is peeled off owing to the bonding force of the centrifugal force that acts on l Water Paper 120, l Water Paper 120 and all conditions such as clamp pressure of compress variation, the first drying cylinder 202a and niproll 201b, so the relaxation that is produced of peeling off of this l Water Paper 120 is unsettled, can become the reason of disconnected paper, making can not the fast and stable running.
In addition, can consider in order to following method, promptly by the peripheral speed of the first drying cylinder 202a being set (promptly greater than the speed of travel of the felt 201c of final squeezing unit 201a, traction l Water Paper 120), eliminate l Water Paper 120 in the compression of downstream generation of final squeezing unit and relaxing of between C, D, producing at above-mentioned.But, for the peripheral speed of the first drying cylinder 202a being set, need make niproll 201b leave the first drying cylinder 202a, thereby the clamping that makes the niproll 201b and the first drying cylinder 202a is separately, or reduces clamp pressure greater than the speed of travel of felt 201c.
During this occasion, because when pushing with felt 201c, l Water Paper 120 pushing on the first drying cylinder 202a is insufficient, makes l Water Paper 120 to the transmission of the first drying cylinder 202a instability that becomes.
Like this, even can make paper machine the structure of the fast turn-around of non-open draw, as mentioned above, with the elongation that produces in final squeezing unit, in phase I elongation and second stage elongation that drying unit produces is cause, cause producing disconnected paper, institute is so that running is unstable, and the result can not carry out fast turn-around.
The specific embodiment
Below, with reference to the description of drawings embodiments of the present invention.
Fig. 1 and Fig. 2 are the figure of the paper machine of expression an embodiment of the invention, and Fig. 1 represents the side view of the formation pattern of paper machine of the present invention, and Fig. 2 represents the side view of its local formation pattern.
The paper machine that the present invention relates to, its pith as shown in Figure 1, be provided with each equipment of wire netting unit (ply of paper formation operation) X, pressing device (dehydration procedure) Y, drying device (drying process) Z successively from upstream side, go out the structure that interruption-forming does not carry out open draw (l Water Paper is not subjected to the no supporting and space of any support) from wire netting unit X to pressing device Y.In addition, though not shown, in the downstream of drying device Z, be provided with gloss operation and coiling process successively from upstream side, its Surface Machining is level and smooth through pressing device Y and the dried cardboard of drying device press for extracting juice water at drying process, make the web-like paper product at coiling process.
In addition, wire netting unit X has: ejection is as the liquid stream box 1 of the pulp suspension (fiber+dispersion liquid) of paper material liquid; A pair of (2) ring networks (wire netting) 2,3 of synchronous walking; Being arranged on ply of paper forms the operation upstream, passes through net 2,3 mutual opposed attraction roller 4 and wire rolls 5; And be arranged on the Water Extraction Machinery 6,7 in its downstream by net 2,3, also be provided with by net 3 in its downstream and attract roller 8.
Net 2 is by attracting roller 4, wire roll 5, a plurality of guide roller 53 supporting, and driven guiding by these each rollers 4,51,53 and walk.Net 3 is being supported by wire roll 5, wire roll 52, a plurality of guide roller 54, and is driven guiding by these each rollers 5,52,54 and walk.
In this wire netting unit X, from the pulp suspension of liquid stream box 1 entered wire roll 5 by spraying to and attract between the roller 4 net 2,3 each other, and clipped transmission by two nets 2,3.When transmitting, pulp suspension makes fiber separate with dispersion liquid and forms l Water Paper by mesh in the operation that is sandwiched while dewatering through Water Extraction Machinery 6,7 between the net 2,3.
At pressing device Y thereafter, its upstream is provided with a pair of (2) annular felts (strip-shaped parts) 12,13, its downstream is provided with a pair of (2) annular felts (strip-shaped parts) 18,19.
The felt 12 that is arranged on the upstream side of pressing device Y attracts to be rolled into around shape on rollers 11, pressure roller 14, a plurality of guide roller 55 at two, in addition, be provided with motor (driver element) on any roller in attracting roller 11, pressure roller 14, be used for driving felt 12 with roller even l Water Paper one, felt 12 is driven guiding by these rollers 11,14,55 and walks.According to this formation, l Water Paper is being supported by felt 12 and is transmitting, and constitutes conveyer mechanism of the present invention by felt 12, each roller 11,14,55.
Felt 13 with felt 12 opposite disposed, on pressure roller 15, attraction roller 16, a plurality of guide roller 56, be rolled into around shape, in addition, on pressure roller 15 or attraction roller 16, be provided with CD-ROM drive motor (driver element), felt 13 is driven guiding by these rollers 15,16,56 and walks, and constitutes conveyer mechanism of the present invention by felt 13, each roller 15,16,56.
Be placed on the l Water Paper that is transmitted on the net 3 of wire netting unit X, be attracted and be sent on the felt 12, when being clipped transmission, through pressure roller 14,15 pressurized and dehydrations by the felt 12,13 of two walkings by attracting roller 11.Like this, utilize pressure roller 14,15 to constitute squeezing of the present invention unit.
Through leaving the part of felt 12,13 in the l Water Paper behind the pressure roller 14,15, be sent on the felt 13 by attracting roller 16.
The upside felt (strip-shaped parts) 18 that is arranged on pressing device Y downstream is rolled into around shape on attraction roller 17, pressure roller 20, a plurality of guide roller 57, in addition, attracting to be provided with CD-ROM drive motor (driver element) on roller 17 or the pressure roller 20, felt 18 is driven guiding by these rollers 17,20,57 and walks.Be rolled into around shape on pressure roller 21, a plurality of guide roller 58 with downside felt (strip-shaped parts) 19 of felt 18 opposite disposed, in addition, be provided with CD-ROM drive motor (driver element) on pressure roller 21, felt 19 is driven guiding by these rollers 21,58 and walks.
Like this, utilize above-mentioned felt 18 and each roller 17,20,57, and above-mentioned felt 19 and each roller 21,58 constitute conveyer mechanism of the present invention respectively.
Be placed on the l Water Paper that is transmitted on the felt 13, be attracted and be sent on the felt 18 by attracting roller 17, when being clipped transmission by the felt 18,19 of two walkings, the pressurized and dehydration through final squeezing unit (pressure roller 20,21).Like this, utilize pressure roller 20,21 to constitute squeezing of the present invention unit.Be sent on the felt 19 through the l Water Paper behind the pressure roller 20,21, and be sent to drying device Z by suction roll 23.
In final squeezing unit, if use shoe press (シ ユ one プ レ ス) to replace pressure roller 21,21, will be desirable more, in addition, the viewpoint of the most moistening from preventing (moisture of squeezing out from l Water Paper is absorbed by l Water Paper once more) is considered, then preferably uses fluid-tight transmission to bring and replaces downside felt 19.
As shown in Figure 1, be provided with annular canvas (strip-shaped parts) 22a~22c, l Water Paper reverse roll (below, be called for short reverse roll) 23a~23c, drying cylinder (drying unit) 25a~25d and suction box 27a~27d in the upstream of drying device Z.The never illustrated outside vapor source of each drying cylinder 25a~25d is to the internal feed steam, the l Water Paper 10 that transmits from pressing device Y by canvas 22a~22c by successively by on the periphery that is pressed in drying cylinder 25a~25d, and be heated drying.
The canvas 22a of upstream with as the upstream side cylinder of first drying unit (below, being called for short first drying cylinder) 25a is opposite disposed, this canvas 22a is set up around shape on suction roll 23 and a plurality of guide roller 59, is pressed against on the first drying cylinder 25a in the ring-type outside simultaneously.Canvas 22a is being supported by above-mentioned suction roll 23, drying cylinder 25a and guide roller 59, and is driven by suction roll 23 or drying cylinder 25a, is being guided by above-mentioned guide roller 59 simultaneously and is walking.
The canvas 22b that is positioned at canvas 22a downstream and upstream side as second drying unit play second cylinder (below, be called for short second drying cylinder) 25b and upstream side, and to play the 3rd cylinder (below, be called for short the 3rd drying cylinder) 25c be opposite disposed.This canvas 22b is being supported by above-mentioned cylinder 25b, 25c, reverse roll 23a, 23b and a plurality of guide roller 60, and is driven or is guiding and walk.
Like this, utilize canvas 22a, drying cylinder 25a and guide roller 59, and canvas 22b, cylinder 25b, 25c, reverse roll 23a, 23b and guide roller 60, respectively conveyer mechanism of the present invention and drying unit are constituted one.
Fig. 1 has only represented inlet portion, be positioned at canvas 22b more downstream canvas 22c with from l Water Paper direction of transfer upstream side the 4th cylinder (below, being called for short the 4th drying cylinder) 25d is opposite disposed, supporting by above-mentioned cylinder 25d and reverse roll 23c and a plurality of guide roller 61, and be driven or guiding and walk.
Below, further specify drying device Z with reference to Fig. 2.For convenience, in Fig. 2, dot l Water Paper 10.
L Water Paper 10 on the downside felt 19 of final squeezing unit is at first attracted by suction roll 23 with canvas 22a by the first drying cylinder 25a and has got, and then, is pressed against on the first drying cylinder 25a by canvas 22a.
In the loop wire of canvas 22a, between suction roll 23, the first drying cylinder 25a, be provided with l Water Paper adsorbent equipment (being to make the absorption box that produces negative pressure) 27a herein, 27a is adsorbed onto l Water Paper 10 on the canvas 22a by this absorption box, to prevent leaving canvas 22a during l Water Paper 10 is sent to the first drying cylinder 25a from suction roll 23.
In addition, canvas 22a l Water Paper 10 by being pressed in some H on the first drying cylinder 25a periphery to (canvas 22a is being pressed against a H between the some K by l Water Paper 10 on the first drying cylinder 25a periphery) between the some K.The canvas 22a that leaves behind the first drying cylinder 25a periphery enters the backhaul loop wire from guide roller 59a, returns above-mentioned suction roll 23 via other guide rollers and not shown stretching device and cleaning device etc.
Guide in the guide roller 60 of the 2nd canvas 22b walking, the guide roller 60a that is provided with near the first drying cylinder 25a has not shown travel mechanism, can move along advancing and retreat shown in Fig. 2 arrow relative to the first drying cylinder 25a.By adjusting the position of this guide roller 60a, can adjust the walking line of the 2nd canvas 22b, the walking line of the 2nd canvas 22b is configured to make it near to or in contact with the periphery of the first drying cylinder 25a at a L.In addition,, can adjust the gap of the 2nd canvas 22b and the first drying cylinder 25a, or adjust the exposure level (clamp pressure and the amount of contact) of the 2nd canvas 22b and the first drying cylinder 25a by adjusting the position of this guide roller 60a.Lax for l Water Paper 10 is produced, the position adjustment of guide roller 60a can be according to the setting that suit of various conditions such as the kind of l Water Paper 10 and running speed.
Here, above-mentioned some L be l Water Paper 10 not by the 2nd canvas 22b by being pressed in the first drying cylinder 25a when going up, leave the pick-up point of the first drying cylinder 25a.So-called contact is meant that the roughly approximate point of contacting of the 2nd canvas 22b and the first drying cylinder 25a contacts the contact condition the when clamp pressure of the 2nd canvas 22b and the first drying cylinder 25a is approximately zero approximately.
In addition, peel off easily in order to make the l Water Paper 10 after being pressed, the periphery of the first drying cylinder 25a is covered with pottery.In addition, on the first drying cylinder 25a, be not provided with wing 28,29 and air nozzle 35 herein by the periphery that is pressed with l Water Paper 10 (below referring to), the front end sliding-contact cylinder periphery of wing 28,29, air nozzle 35 is to cylinder periphery jet-stream wind.Even the wing 28 of cylinder rotation direction upstream side and exhaust nozzle 35 are used at l Water Paper 10 by above-mentioned some L but still when sticking on the cylinder periphery, this l Water Paper 10 is peeled away from the cylinder periphery.The wing 29 in cylinder rotation direction downstream is used to clear up the attachment on the cylinder periphery, makes this cylinder periphery keep clean.Like this, keep clean, can make l Water Paper 10 stably shift (for example, making l Water Paper 10 roughly keep certain) apart from the position of peeling off of cylinder periphery to next stage by making the cylinder periphery.
The second canvas 22b one is through above-mentioned some L, just the periphery by l Water Paper reverse roll 23a is pressed against on the periphery of the second drying cylinder 25b, then, as shown in Figure 1, after l Water Paper reverse roll 23b, the 3rd drying cylinder 25c, return guide roller 60a through guide roller 60 and not shown stretching device and cleaning device etc. again.
Be provided with l Water Paper adsorbent equipment (being to make the absorption box that produces negative pressure) 17b in the loop wire of the second canvas 22b herein, l Water Paper reverse roll 23a makes its periphery produce negative pressure, and l Water Paper 10 and canvas 22b are adsorbed on the above-mentioned periphery integratedly.Like this, can stably be delivered to l Water Paper 10 on the second canvas 22b from the first canvas 22a.
In order to make l Water Paper 10 stabilized walking between some K, the L on the periphery of drying cylinder 25a, it is 1000~4000cc/cm that the second canvas 22b preferably uses venting quality
2Min@1/2 " AQ[1000~4000cm
3/ cm
2Min@1/2 (differential pressure is 124.5Pa)] canvas.
As mentioned above, be respectively equipped with conveyer mechanism at the final squeezing unit of forming by pressure roller 20,21, the first drying cylinder 25a and the second drying cylinder 25b, can set the speed of the canvas 22b of the canvas 22a of canvas 18,19, the first drying cylinder 25a of final squeezing unit and the second drying cylinder 25b respectively.That is, can set the l Water Paper transfer rate respectively, can draw l Water Paper 10 each other at them at final squeezing unit, drying cylinder 25a, 25b.
Here, consider the elongation (about 3%) of the l Water Paper 10 that produces in final squeezing unit, in order to draw the speed of travel V of the canvas 22a of the first drying cylinder 25a to l Water Paper 10
1, for example, can be set at final press speed (that is the speed of travel of upside felt 18 and downside felt 19) V arbitrarily
0High-speed (the V below 1.04 times
0<V
1≤ 1.04V
0).That is, the driver element of driving canvas 22a (driving the motor of either party among the suction roll 23 or the first drying cylinder 25a) is used for the speed of travel of canvas 22a is set at the interior arbitrary speed of above-mentioned scope.V
1Surpass V
01.04 times the time, form hyper-traction, wet web strength reduces, the drying cylinder in the downstream produces disconnected paper, can not fast turn-around, so be preferably V
0Below 1.03 times.
Consider as the prior art problem illustrated at the elongation of phase I that the first drying cylinder 25a might produce (below 1.0%, common 0.5%), in order to draw to l Water Paper 10, the speed of travel of the canvas 22b of the second drying cylinder 25b and the 3rd drying cylinder 25c for example can be V
2Be set at V arbitrarily
1The speed (V below 1.01 times
1<V
2≤ 1.01V
1).That is, drive canvas 22b driver element (driver inversion roller 23a, 23 and or drying cylinder 25a, 25b in either party's motor) be used for the speed of travel of canvas 22a is set at the interior arbitrary speed of above-mentioned scope.
Here, as mentioned above, be respectively equipped with conveyer mechanism at drying cylinder 25b, 25c and the 4th drying cylinder 25d.Like this, can set the speed of the canvas 22c of the speed of canvas 22b of drying cylinder 25b, 25c and the 4th drying cylinder 25d respectively, and set the l Water Paper transfer rate of drying cylinder 25b, 25c and the l Water Paper transfer rate of the 4th drying cylinder 25d respectively.
Generally, in drying device, l Water Paper heats up rapidly by meeting in the process of several drying cylinders of upstream side, but normally reaches poised state about 80 ℃, and afterwards, the moisture in the l Water Paper evaporates at a certain temperature.Suppose that be 20 ℃ to the l Water Paper temperature of drying device porch, the coefficient of expansion of water when 20 ℃ are warmed up to 80 ℃ is about 2.7%.Because l Water Paper has fiber orientation, so its inflation status is also different because of direction, supposes that expansion in any direction all is impartial, is about 1% when the above-mentioned coefficient of expansion is scaled linear expansion coefficient.That is, the elongation of the second stage of l Water Paper 10 is about 1%.
Therefore, if the speed of travel V of the canvas 22c of the 4th drying cylinder 25d
3Be set at the speed of travel V of upstream side canvas 22b
2About 1.01 times, can absorb the second stage elongation of l Water Paper 10, drive that the drive source (for example, the motor of rotating drive drying cylinder) of canvas 22c is selected to be set at above-mentioned speed to the speed of travel of canvas 22c.
At drying device Z, before the temperature of l Water Paper 10 reaches about 80 ℃ of above-mentioned equilibrium temperature, l Water Paper 10 produces the second stage elongation, so be preferably in each drying cylinder canvas loop wire and the drive source of this canvas loop wire of speed drive (conveyer mechanism is set respectively) in accordance with regulations is set respectively.But, as mentioned above, the intensification of l Water Paper 10 (being the second stage elongation) becomes big near the inlet of drying device Z, in its downstream, l Water Paper 10 do not heat up substantially (be second stage elongation), result of the test according to inventor's experimental prototype can be distinguished, in order to absorb at least the elongation of the l Water Paper 10 that produces at the second drying cylinder 25b, if the drying cylinder in the downstream of the second drying cylinder 25b is provided with other conveyer mechanisms of at least one conveyer mechanism that is different from the second drying cylinder 25b, can fully suppress the lax of l Water Paper 10.
The paper machine of an embodiment of the invention adopts above-mentioned formation, by the speed V of the first canvas 22a
1Set greater than final press speed V
0(V
0<V
1), same as the prior art at the first drying cylinder 25a when absorbing the elongation of the l Water Paper 10 that produces when finally squeezing, l Water Paper 10 produces the phase I elongation, but passes through the speed V of the second canvas 22b
2Set greater than the speed V of the first canvas 22a
1(V
1<V
2), can absorb this elongation.
Therefore, can make l Water Paper 10 not have to be sent to the second drying cylinder 25b under the lax state on the second canvas 22b, l Water Paper 10 is in the state that is supported fully by the second canvas 22b and reverse roll 23a and the second drying cylinder 25b, can prevent fully that to produce owing to l Water Paper is lax that stress that wrinkle causes concentrates be the disconnected paper of cause.
At this moment,, set up the drying cylinder 25d of the 3rd canvas 22c, can set the speed of travel of the second canvas 22b and the 3rd canvas 22c respectively all having set up drying cylinder 25b, the 25c of the second canvas 22b.
So, pass through in the dry gradually process of drying device Z quilt at l Water Paper 10, particularly after the second drying cylinder 25b, l Water Paper 10 produces elongation, but,, can absorb above-mentioned elongation if must come the speed setting of the 3rd canvas 22c l Water Paper 10 is drawn greater than the speed of the second canvas 22b, it is lax to prevent that l Water Paper 10 from producing on the 3rd canvas 22c, and can prevent disconnected paper.
When even the speed of l Water Paper is fast, as mentioned above, also can make l Water Paper 10 drying device Z stabilized walking and in the past than, disconnected paper frequency significantly reduces, and can carry out papermaking under the quick l Water Paper speed of travel of 2000m/min.
Paper machine of the present invention is not limited to above-mentioned embodiment, and the various distortion that do not break away from the aim scope of the present invention all are feasible.
For example, in the above-mentioned embodiment, the second drying cylinder 25b and the 3rd drying cylinder 25c are shared conveyer mechanisms, but also can conveyer mechanism be set respectively at the second drying cylinder 25b and the 3rd drying cylinder 25c, between these drying cylinders 25b, 25c l Water Paper 10 are drawn.Stage absorbs the second stage elongation that l Water Paper 10 produces at the second drying cylinder 25b like this, in early days.
In addition, felt 18,19, each speed of travel V of canvas 22a, 22b, 22c
0, V
1, V
2, V
3, being not limited to the illustrated number range of embodiment, in order to absorb the elongation of l Water Paper 10, can suit to set.The invention effect
According to paper machine of the present invention, squeezing unit in the downstream of the l Water Paper direction of transfer that is positioned at pressing device, first drying unit from the l Water Paper direction of transfer upstream side of pressing device, be respectively equipped with this conveyer mechanism with second drying unit from the l Water Paper direction of transfer upstream side of pressing device, in the squeezing unit that is positioned at above-mentioned downstream, first drying unit and second drying unit, control the action of the driver element of conveyer mechanism respectively, set the transfer rate of l Water Paper respectively, thus, can set the l Water Paper transfer rate of first drying unit greater than the l Water Paper transfer rate of the squeezing unit in downstream, and, set the l Water Paper transfer rate of second drying unit greater than the l Water Paper transfer rate of first drying unit, like this, have and to prevent that l Water Paper from producing lax and disconnected paper before and after first drying unit, realize stablizing the advantage of quick papermaking.
At this moment, if the l Water Paper transfer rate of first drying unit is set at high-speed below 1.04 times of l Water Paper transfer rate of the squeezing unit in downstream, the l Water Paper transfer rate of second drying unit is set at high-speed below 1.01 times of the l Water Paper transfer rate of above-mentioned first drying unit, can effectively suppress the disconnected paper of l Water Paper, realize stablizing quick papermaking.
In this pressing device, if the walking line along l Water Paper is arranged three above drying units, at the 3rd any the later drying unit of l Water Paper direction of transfer upstream side and second drying unit conveyer mechanism is set respectively from drying device, and the l Water Paper transfer rate of the 3rd any later drying unit is set at high-speed below 1.01 times of the l Water Paper transfer rate of second drying unit, the elongation of the main l Water Paper that causes because of heating that can be absorbed in that second drying unit produces further effectively suppresses the lax of l Water Paper.