CN103261516B - For being dried the drying baker including at least two district of cellulose pulp mesh sheet - Google Patents

Abstract

One is used for being dried the arrangement of a cellulose pulp mesh sheet (18), including a drying baker (1), this drying baker (1) includes multiple blow box (26,32), these blow boxs (26,32) can operate and blow air for towards this cellulose pulp mesh sheet (18), thus are dried paper pulp according to unsettled mesh sheet principle.This drying baker (1) includes first dry section (4) and second dry section (6), this first dry section includes the multiple first bottom blow boxs (26) being arranged to for supporting this mesh sheet (18), this second dry section includes the multiple second bottom blow boxs (32) being arranged to for supporting this mesh sheet (18), and wherein these first bottoms blow box (26) are different from these the second bottoms blow box (32).

Description

For being dried the drying baker including at least two district of cellulose pulp mesh sheet

Invention field

The present invention relates to a kind of arrangement for being dried cellulose pulp mesh sheet (web) in drying baker, these dry case and bag Including multiple blow box, these blow boxs can operate and blow air for towards cellulose pulp mesh sheet, thus according to unsettled net Sheet principle is dried paper pulp.

The invention further relates to a kind of method for being dried cellulose pulp mesh sheet, be by by means of multiple blowings Case blows air towards cellulose pulp mesh sheet thus is dried paper pulp according to unsettled mesh sheet principle.

Background of invention

In the convection type drier run according to unsettled mesh sheet principle, generally it is dried cellulose pulp.WO2009/ The example of this exsiccator is described in 154549.By means of multiple tops blow box and bottom blow box, blowing hot air is arrived In cellulose pulp mesh sheet.The air blowed by blow box transfers heat to mesh sheet and makes mesh sheet be dried, and also keeps net Sheet floats on the top of bottom blow box.By means of a circulation air system, hot-air being fed to blow box, this circulation is empty Gas system includes multiple fan and the multiple steam radiators heating dry air.

Along with the demand increasing pulp production in pulp mill increases day by day, need to increase the dry energy of pulp dryer Power, and do not increase its size or only somewhat increase its size.

Summary of the invention

It is an object of the invention to provide a kind of arrangement for being dried cellulose pulp mesh sheet, this arrangement ratio is existing The arrangement of technology more has space efficiency.

This purpose is by mean of a kind of arrangement for being dried a cellulose pulp mesh sheet in a drying baker and comes Realizing, this drying baker includes multiple blow box, and these blow boxs can operate and blow sky for towards this cellulose pulp mesh sheet Gas, thus be dried paper pulp according to unsettled mesh sheet principle, wherein this drying baker include first dry section and one second dry Dry district, this first dry section includes the multiple first bottom blow boxs being arranged to for supporting this mesh sheet, this second dry section Including the multiple second bottom blow boxs being arranged to for supporting this mesh sheet, wherein these the first bottom blow boxs are different from this A little second bottom blow boxs.

This advantage arranged is can to optimize to be dried paper pulp mesh sheet in each dry section, in order to adapt to In this given zone about drying condition, paper pulp mesh sheet intensity etc. in terms of account for leading condition.And then can use and prior art Compare less exsiccator to realize enough drying capacities.

According to an embodiment, this first dry section is arranged at the upstream of this second dry section, as at this cellulose paper Finding on the direction that slurry mesh sheet is advanced.In the case of dry section is with this sequencing, these dry sections can be for multifrequency nature Carrying out adaptation, such as mesh sheet intensity, mesh sheet aridity etc., these characteristics advance through drying baker along with mesh sheet and change.

According to an embodiment, flow down at every square metre of horizontal net sheet area and a certain air of unit interval, the most right For a distance between corresponding bottom blow box and this cellulose pulp mesh sheet, the phase of these the second bottom blow boxs The power of lifting is higher than the power of relatively lifting of these the first bottom blow boxs.One advantage of this embodiment is, the second bottom blowing Mesh sheet can be dried by case with higher efficiency, this higher efficiency bigger distance often and between mesh sheet with corresponding blow box Relevant.

According to an embodiment, each dry section includes at least four continuous print bottom blow box.

According to an embodiment, as long as the distance between bottom blow box and this cellulose pulp mesh sheet of at least correspondence is 2 to 8 millimeters, the power of relatively lifting of these the second bottom blow boxs is just higher than the power of relatively lifting of these the first bottom blow boxs. One advantage of this embodiment is: in the range of this of the distance between mesh sheet and bottom blow box, the second bottom blow box Power of relatively lifting higher than the power of relatively lifting of the first bottom blow box, be dried the most most effective in the case.

According to an embodiment, these the first bottom blow boxs possess multiple apsacline opening, these apsacline opening quilts It is adapted to a upper side with corresponding blow box at an angle by the air being fed to these the first bottom blow boxs At least some of ejection.One advantage of this embodiment is: the first bottom blow box can apply a bed knife to mesh sheet, Thus contribute to making mesh sheet stable in the first dry section.

According to an embodiment, this drying baker includes several dry platens, and each dry platen includes multiple bottom Blow box and be adapted for advancing along horizontal route at a certain height of this drying baker in this mesh sheet Time this mesh sheet is dried, wherein this first dry section include this drying baker dry platen sum 10%-70%.This implements One advantage of example is: the first dry section has suitable length, so that mesh sheet is dried to a certain degree and obtains increase Intensity, so that the increase that contingent mesh sheet in the second dry section is stretched by mesh sheet is less sensitive.

According to an embodiment, this first bottom blow box possesses multiple apsacline opening, and these apsacline openings are fitted It is made at least 30% ejection in the air being fed to these the first bottom blow boxs, and wherein this second bottom blow box Possessing multiple non-inclined type opening, these non-inclined type openings are adapted to the air by being fed to these the second bottom blow boxs In at least 75% ejection.One advantage of this embodiment is: the first bottom blow box provides a bed knife to mesh sheet, and the Two bottom blow boxs are efficient to the dry of mesh sheet.

According to an embodiment, at least the 75% of these bottom blow boxs of this first dry section is that described first bottom is blown Bellows, and at least the 75% of these bottom blow boxs of this second dry section is described second bottom blow box.This embodiment One advantage is: the first dry section makes mesh sheet advance along stabilizing path effectively, and mesh sheet is entered by the second dry section effectively Row is dried.

It is yet another object of the invention to provide a kind of with the method more efficient way than prior art to cellulose pulp The method that mesh sheet is dried.

This purpose is by mean of a kind of method for being dried cellulose pulp mesh sheet and realizes, the method by by Blow air in multiple blow boxs towards cellulose pulp mesh sheet, thus be dried paper pulp, the method according to unsettled mesh sheet principle Including: making this mesh sheet advance through first dry section, this first dry section includes multiple first bottoms supporting this mesh sheet Blow box；And then making this mesh sheet advance through second dry section, it is many that this second dry section includes supporting this mesh sheet Individual second bottom blow box, these the second bottom blow boxs are different from these the first bottom blow boxs.

One advantage of the method is so that be dried more effectively, and can make to be dried this mesh sheet of adaptation along net Different mechanical strengths in the diverse location on path that sheet advances.

According to an embodiment, the average distance between this mesh sheet and these the second bottom blow boxs more than this mesh sheet and this Average distance between a little first bottom blow boxs.One advantage of this embodiment is: bigger average distance improves heat biography Pass.

According to an embodiment, be fed in total air mass flow of these the first bottom blow boxs at least 30% is and that The corresponding upper side of a little first bottom blow boxs becomes the angle less than 60 ° to blow out from these the first bottom blow boxs, and Wherein be fed in total air mass flow of these the second bottom blow boxs at least 75% is right with those the second bottom blow boxs Upper side is answered to become the angle of at least 75 ° to blow out from these the second bottom blow boxs.One advantage of this embodiment is: One dry section obtains effectively fixing mesh sheet, and obtains efficient heat transfer in the second dry section.

According to an embodiment, this mesh sheet is above these the first bottom blow boxs at the average distance of 0.2 to 3 millimeters Advance and advance at the average distance of 4 to 15 millimeters above these the second bottom blow boxs.One advantage of this embodiment It is the first bottom blow box to the most stable of mesh sheet and the second bottom blow box to effective heat transfer of mesh sheet.

The other objects and features of the invention will be apparent from from explanation and claims.

Brief Description Of Drawings

It is more fully described the present invention, in the accompanying drawings referring now to the following drawings:

Fig. 1 is schematic side elevation, and illustrates the drying baker of mesh sheet for being dried cellulose pulp.

Fig. 2 is schematic side elevation, and illustrates the region II of Fig. 1.

Fig. 3 describes schematic plan and sectional view, and illustrates institute on the direction such as the arrow III-III of Fig. 2 The the first bottom blow box seen.

Fig. 4 is schematic side elevation, and illustrates the region IV of Fig. 1.

Fig. 5 is schematic plan, and illustrates the second bottom seen on the direction such as the arrow V-V of Fig. 4 Blow box.

Fig. 6 is a chart, and illustrates by the first and second bottom blow box in the vertical directions in paper pulp mesh sheet The power of upper applying.

Fig. 7 is a chart and the heat transfer illustrating the first and second bottom blow boxs.

The explanation of preferred implementation

Fig. 1 illustrates the drying baker 1 for being dried cellulose pulp according to the first embodiment of the present invention.Drying baker 1 Including shell 2.In shell 2, arrange to have the first dry section the 4, second dry section 6 and optional cooling zone 8, wherein first be dried District 4 is arranged in the upper area of shell 2, and cooling zone 8 is arranged in the lower area of shell 2, and the second dry section 6 arranges Between the first dry section 4 and cooling zone 8.

At the first end 10 of shell 2, it is scheduled that multiple revolving rolls 12 of first row, and at the second end 14 of shell 2 Place, is scheduled that multiple revolving rolls 16 of secondary series.Moistening paper pulp mesh sheet 18 enters dry via the entrance 20 being arranged in shell 2 Dry case 1.In the embodiment in figure 1, entrance 20 is arranged in the top of shell 2, but in alternative embodiments, this entrance is permissible It is arranged in the bottom of shell.Mesh sheet 18 is flatly advanced towards the right in drying baker 1 as shown in fig. 1, until mesh sheet 18 Till arriving a revolving roll.In drying baker 1 shown in FIG, mesh sheet 18 will arrive first in the multiple revolving roll of secondary series A revolving roll 16.Mesh sheet 18 is turned around revolving roll 16, and then in drying baker 1 as shown in fig. 1 towards the left side Flatly advancing, until mesh sheet 18 arrives a revolving roll 12 in the multiple revolving roll of first row, mesh sheet 18 is more in this place Secondary turning.In this way, mesh sheet 18 enters bottom from the top row of drying baker 1 in a zigzag manner, as indicated by the arrowp.? After being dried in the first and second dry sections 4,6 and cooling down in cooling zone 8, mesh sheet 18 is via being arranged in shell 2 In outlet 22 leave drying baker 1.In the embodiment in figure 1, outlet 22 is arranged in the bottom of shell 2, but real substituting Executing in example, this outlet can be arranged in the top of shell.

Typically, dry run is used the air of the temperature of 80 ° of C to 250 ° of C.From a upstream mesh sheet forming station (Fig. 1 Not shown) the cellulose pulp mesh sheet 18 that enters drying baker 1 typically has the dry solids content of 40%-60% weight, and The cellulose pulp mesh sheet 18 leaving drying baker 1 typically has the dry solids content of 85%-95% weight.When doing at every kilogram When dry material is to measure under the moisture content of 0.11 kg water and the thickness of 0.8 to 3 millimeters, leave the cellulose of drying baker 1 Paper pulp mesh sheet 18 typically has 800 to 1500g/m²Basis weight.

First dry section 4 includes that at least one first is dried platen 24, and typically 3 to 15 first are dried platen 24. In the embodiment in figure 1, the first dry section 4 includes that 8 first are dried platen 24.Each this first is dried platen 24 and includes Some blow boxs, as described in more detail below, and can operate in mesh sheet 18 from a revolving roll 12,16 water Level land advances to be dried this mesh sheet 18 during next revolving roll 16,12.Each first is dried platen 24 and includes some first time Portion's blow box 26 and some first top blow boxs 28, these blow boxs are arranged to for blowing towards cellulose pulp mesh sheet 18 Send the dry gas of heat.Typically, each first is dried platen 24 and includes that 20 to 300 the first bottom blow boxs 26 are with identical First top blow box 28 of number, but in FIG in order to keep the clear of diagram, illustrate only several blow box.First time Portion's blow box 26 can operate for mesh sheet 18 being maintained under " floating " and fixing state, so makes mesh sheet 18 be dried It is unsettled during process and the first bottom blow box 26 has certain distance, as described in more detail below.

Second dry section 6 includes that at least one second is dried platen 30, and typically 5 to 40 second are dried platen 30. In the embodiment in figure 1, the second dry section 6 includes that 11 second are dried platen 30.Each this second is dried platen 30 and wraps Include some blow boxs, as described in more detail below, and can operate in mesh sheet 18 from a revolving roll 12,16 water Level land advances to be dried this mesh sheet 18 during next revolving roll 16,12.Each second is dried platen 30 and includes some second time Portion's blow box 32 and some second top blow boxs 34, these blow boxs are arranged to for blowing towards cellulose pulp mesh sheet 18 Send the dry gas of heat.Typically, each second is dried platen 30 and includes that 20 to 300 the second bottom blow boxs 32 are with identical Second top blow box 34 of number, but in FIG in order to keep the clear of diagram, illustrate only several blow box.Second time Portion's blow box 32 can operate and be maintained under " floating " state for by mesh sheet 18 so that mesh sheet 18 becomes during dry run Unsettled and the second bottom blow box 32 has certain distance, as described in more detail below.

The first of first dry section 4 is dried platen 24 and is dried platen 30 from the second of the second dry section 6 and has different machines Tool designs, as described in more detail below.First the first bottom blow box 26 and second being dried platen 24 is dried platen 30 The second bottom blow box 32 often there is different Machine Designs, as illustrated below.Each dry section 4,6 is typically At least four continuous print correspondence blow box 26,32 will be included.So that it takes up a position, for example, the first dry section 4 will typically comprise at least Four continuous print the first bottom blow boxs 26, and the second dry section 6 will typically comprise at least four continuous print the second bottom Blow box 32.Each dry section 4,6 typically will include the dry platen 24,30 that at least one is complete, be included in corresponding dry Blow box 26,28,32,34 included in dry platen 24,30.

Cooling zone 8 includes at least one cooling slab 36, illustrates two this cooling slabs 36 in FIG, each This platen 36 includes some 3rd bottom blow box 38 and the 3rd top blow boxs 40, and these blow boxs are arranged to for court Cooling gas is blowed to cellulose pulp mesh sheet 18.Bottom blow box 38 can operate for mesh sheet 18 is maintained at " floating " shape Under state so that mesh sheet 18 becomes unsettled during cooling procedure.Typically, cooling procedure is used the temperature of 15 ° of C to 40 ° of C Air as cooling gas.Second dry section 6 is separated by one dividing wall 42 with cooling zone 8.

Fig. 2 is the enlarged side view of the region II of Fig. 1, and illustrates in Fig. 1 the first dry section 4 first dry of diagram A part for dry platen 24.First be dried platen 24 include being arranged in the multiple first bottom blow boxs 26 below mesh sheet 18, with And it is arranged in the multiple first top blow boxs 28 above mesh sheet 18.As in Fig. 2 illustrate, first be dried platen 24 can include to Few four continuous print the first bottom blow boxs 26.Therefore, in Fig. 1, the first dry section 4 of diagram can include that at least four is continuous The first bottom blow box 26.These the first bottom blow boxs 26 such as arrow VU in Fig. 2 diagram vertically upright towards net Sheet 18 and angle the doing heat in an inclined manner typically becoming 5 to 60 ° with horizontal plane illustrated such as the arrow IU in Fig. 2 Dry air blows to mesh sheet 18.The example of the blow box that can serve as the first bottom blow box 26 is described in WO97/16594, For example, see Fig. 2 of the document and 3.Return to Fig. 2 of subject application, blow the first bottom blow box 26 and horizontal plane Dry air creates and forces mesh sheet 18 be upwardly away from the power of blow box 26 and force mesh sheet 18 downwardly blow box 26 Power.This will cause blow box 26 to apply bed knife in mesh sheet 18, thus mesh sheet is maintained at blow box 26 at a distance of a phase When the distance well defined.Typically, at the run duration of drying baker 1, the downside of mesh sheet 18 and the first bottom blow box 26 Upper surface between average distance or height H1 be 0.2 to 3 millimeters.If mesh sheet 18 will tend to moving up, then blowing The bed knife of case 26 will drag down mesh sheet 18, and if mesh sheet 18 will tend to moving down, then blow box 26 blows Air will force mesh sheet 18 upwards.Therefore, mesh sheet 18 is dried platen 24 in relatively-stationary mode along first and is horizontally transported, In the vertical direction has minimum movement, it is meant that mesh sheet 18 stands limited tensile force.The top blow box 28 of the first kind Towards mesh sheet 18, the dry air of heat is blowed to mesh sheet 18 vertically downwardly, as the arrow VD in Fig. 2 illustrates.Typically, mesh sheet Average distance or height H2 between upside and the lower surface of the first top blow box 28 of 18 are 10 to 80 millimeters.Blow box 26, the dry air of 28 heat blowed is via the multiple gaps formed between the most neighbouring blow box 26,28 S and discharge.In Fig. 1, the first dry section 4 of diagram often will include at least four continuous print arranged in the way of diagram in Fig. 2 First bottom blow box 26.Additionally, what the first dry section 4 illustrated in Fig. 1 will arrange in the way of often including illustrating in Fig. 2 At least four continuous print the first top blow box 28.

Fig. 3 is schematic plan, and illustrates first seen on the direction such as the arrow III-III of Fig. 2 Bottom blow box 26.Arrow P illustrates mesh sheet (not shown in Fig. 3) and will extend over the upper side 44 time institute of the first bottom blow box 26 Along given route.Upper side 44 includes multiple openings 46 of the first kind at the center that is arranged in, and these openings 46 are sometimes Time is referred to as " apsacline " opening of the type of " eyelid perforation "." apsacline " opening means the sky blowed from those openings 46 At least the 25% of gas is that the upper side 44 with the first bottom blow box 26 becomes the angle [alpha] less than 60 ° to blow, such as the cross section of Fig. 3 Illustrated best in B-B.In the first bottom blow box 26, the total flow of the air being fed in the first bottom blow box is at least 30%, often at least 40% such as blow from these " apsacline " openings via eyelid perforation 46.Via eyelid perforation 46 A part for the air stream blowed can be blowed by the angle more than 60 °, as indicated by the arrow U in the cross section B-B of Fig. 3. In the total air stream being fed to bottom blow box 26, at least 30% is that the upper side 44 with the first bottom blow box 26 becomes to be less than The angle [alpha] of 60 ° blows.

Eyelid perforation 46 can have and be referred to as with WO97/16594 the design that the opening of " eyelid perforation 6 " is similar, and And the Fig. 2 and 3 seeing WO97/16594 describes, these eyelids perforation 46 provides and is blown through the dry of heat therein obliquely Dry air so that create the inclination stream IU of diagram in Fig. 2 of subject application.As in the present application can be seen in Figure 3, these are worn Hole 46 is arranged on face 44 in an alternating manner so that will be directed into the left side every a stream IU, as illustrated in Fig. 3, and often The right will be directed into every a stream IU.

Continuing the description of Fig. 3 of subject application, upper side 44 possesses multiple openings 48 of Second Type, and these openings 48 are pacified Line up the side 50,52 near blow box 26." the non-inclined type " that the opening 48 of Second Type is distributed across in upper side 44 Opening." non-inclined type " means that at least 80% from the air that those openings 48 blow is to become at least 70 ° with upper face 44 Angle blow.Typically, the most whole air stream all blows nearly vertical from the opening 48 of non-inclined type, i.e. The angle close to 90 ° is become with upper face 44.Opening 48 can be circular port, and diameter is typically 1 to 10 millimeters.Second Type Opening 48 be blown up heat dry air and form air-flow VU, this is to be directed vertically upwards reader in the figure 3 representation 's.

By number and the size of the opening 48 of the number of opening 46 and size and Second Type that change the first kind, The suitable pressure drop relation between the opening 46,48 of first and second type can be realized so that be such as blown into the first bottom and blow The 65% of total air stream of bellows 26 sprays via the opening 46 of the first kind, and is blown into the total of the first bottom blow box 26 The 35% of air stream sprays via the opening 48 of Second Type.

Can by by total aperture area of the opening 46,48 of one of upper side 44 representative part divided by this upper side The horizontal projected area of this representativeness part of 44 calculates the degree of perforation of blow box 26." representative part " refers to upper side 44, relative to a part representational for the blow air of mesh sheet, i.e. the air ignoring such as blow box enters Oral area divides.Degree of perforation can for example, 1.5%.Degree of perforation can be changed to adapt to the weight of mesh sheet 18 to be dried, to be dried Property etc..The degree of perforation of the first bottom blow box 26 is often 0.5% to 3.0%.

Fig. 4 is the enlarged side view of the region IV of Fig. 1, and illustrates in Fig. 1 the second dry section 6 second dry of diagram A part for dry platen 30.Second is dried the second bottom blow box 32, Yi Jian that platen 30 includes being arranged in below mesh sheet 18 Come the second top blow box 34 above mesh sheet 18.As illustrated in Fig. 4, second is dried platen 30 can include that at least four is even The second continuous bottom blow box 32.Therefore, in Fig. 1, the second dry section 6 of diagram can include at least four continuous print second time Portion's blow box 32.The dry air of heat is vertically upright blowed to mesh sheet 18, such as Fig. 4 towards mesh sheet 18 by the second bottom blow box 32 In arrow VU diagram.Compared with the first bottom blow box 26 that first as illustrated in Fig. 2 and 3 is dried platen 24, second is dry Second bottom blow box 32 of dry platen 30 applies less bed knife in mesh sheet 18.Second bottom blow box 32 is in mesh sheet 18 The bed knife of upper applying is typically at a fairly low or does not even exist.Return to Fig. 4, supply from the second bottom blow box 32 The dry air of heat mesh sheet is risen to the weight making mesh sheet 18 and the hot dry sky supplied by the second bottom blow box 32 The height that the power of lifting of gas balances each other.Typically, between downside and the upper face of the second bottom blow box 32 of mesh sheet 18 Average distance or height H3 are 4 to 15 millimeters.The bed knife applied in mesh sheet 18 due to the second bottom blow box 32 is limited Or even do not exist, therefore the vertical position of mesh sheet 18 will tend to fluctuation at the run duration of drying baker 1, when dry through second During dry platen 30, than when first is dried platen 24, degree of fluctuation is bigger.Therefore, mesh sheet 18 with mode relatively the most freely along Second is dried platen 30 is horizontally transported, and in the vertical direction has some to move, it is meant that mesh sheet 18 stands some and draws Stretch.The dry air of heat is blowed to mesh sheet 18, such as Fig. 4 towards mesh sheet 18 by the top blow box 34 of Second Type vertically downwardly In arrow VD diagram.Typically, average distance between upside and the lower surface of the second top blow box 34 of mesh sheet 18 or Highly H4 is 5 to 80 millimeters.The dry air of the heat that blow box 32,34 blows is via the most neighbouring blow box 32, multiple gap S of being formed between 34 and discharge.In Fig. 1, the second dry section 6 of diagram often includes with diagram in Fig. 4 At least four continuous print the second bottom blow box 32 that mode arranges.Additionally, the second dry section 6 of diagram often includes in Fig. 1 At least four continuous print the second top blow box 34 arranged in the way of diagram in Fig. 4.

Fig. 5 is schematic plan, and illustrates the second bottom seen on the direction such as the arrow V-V of Fig. 4 Blow box 32.Arrow P illustrates mesh sheet (not shown in Fig. 5) and will extend over during the upper side 54 of the second bottom blow box 32 along which Given route.Upper side 54 extends between the side 56,58 of blow box 32, and includes being distributed in upper side 54 Multiple openings 60 of " non-inclined type ".According to previous definition, " non-inclined type " means the air blowed from those openings 60 In at least 80% be to become the angle of at least 70 ° to blow with upper face 54.Typically, the most whole air stream all will be from non- The opening 60 of apsacline blows nearly vertically, i.e. become the angle close to 90 ° with upper side 54.At the second bottom blow box 32 In, the total flow being fed to the air in this second bottom blow box at least 75% is that the opening from these non-inclined types blows 's.In the embodiment illustrated in Figure 5, the total flow being fed to air therein 100% is the opening from these non-inclined types 60 blow.These openings 60 can be distributed evenly on face 54, but can also be distributed by uneven mode.As from figure 5 is visible, and the closeness (opening number of every square centimeter of upper side 54) of opening 60 is being adjacent at side 56,58 the most more High.The opening 60 of blow box 32 can be circular port, and diameter is typically 1 to 10 millimeters.Opening 60 blows heat straight up Dry air and form air-flow VU, this is directed vertically upwards reader in the diagram of Fig. 5.

Degree of perforation refers to the gross area gross area divided by upper side 54 of opening 60, can for example, 1.5%.Can change Become degree of perforation to adapt to the weight of mesh sheet 18 to be dried, drying property etc..The degree of perforation warp of the second bottom blow box 32 To be often 0.5% to 3.0%.

In Fig. 2, the first of diagram is dried in the first top blow box 28 and Fig. 4 of platen 24 second drying table of diagram Second top blow box 34 of plate 30 can typically have and the second identical being typically designed of lower tank 32 of diagram in Fig. 5, As indicated by the dotted arrow in Fig. 5.Therefore, the first top blow box 28 and the second top blow box 34 can typically possess Can be multiple openings of circular port, a diameter of 1 to 10 millimeters of these openings.

Illustrate in Fig. 5 additionally, the 3rd bottom blow box 38 of cooling zone 8 and the 3rd top blow box 40 can also have The similar design of the second bottom blow box 32, as dotted arrow illustrates.According to an alternate embodiment, the 3rd bottom blow box 38 can have the design similar with the first bottom blow box 26 of diagram in Fig. 3, as dotted arrow illustrates.

Average distance H1, H2, H3, H4 mentioned above all refer to the face 44,54 of corresponding blow box 26,28,32,34 with Beeline between mesh sheet 18.

Fig. 6 be a chart and schematically illustrate by the first the first bottom blow box 26 being dried platen 24 and The example of the power that the second the second bottom blow box 32 in the vertical direction being dried platen 30 applies in mesh sheet 18.In Fig. 2 and 4 The average distance between the downside of mesh sheet 18 with the upper side 44,54 of corresponding blow box 26,32 of diagram or height H1 and H3 Depend on the basis weight of mesh sheet 18 and the balance lifting between power applied in mesh sheet 18 by corresponding blow box 26,32.Should The power of lifting depends on the average distance between the downside of mesh sheet 18 and the upper side 44,54 of corresponding blow box 26,32.In the power of lifting At the average distance during basis weight of mesh sheet, blow box 26,32 power of lifting produced by the air blowed will supporting This mesh sheet, wherein this mesh sheet is with stationary mode " floating ".Therefore, when with stationary mode " floating " downside of mesh sheet 18 with corresponding Basis weight along with mesh sheet is changed by the average distance between the upper side 44,54 of blow box 26,32.

Looked into the model mesh sheet can with various dry solids content by sight, can show that basis weight is with mesh sheet 18 The relation between average distance or height H1 and H3 between downside and the upper side 44,54 of corresponding blow box 26,32.This model Mesh sheet has the relatively basic weight of 1.0 under the dry solids content of 100% weight.This model mesh sheet is when entering exsiccator To there is the dry solids content of only 50% weight, it is meant that this model mesh sheet relatively basic weight when entering exsiccator will Be 2.0 because this mesh sheet in addition to dry solids content possibly together with water.Therefore, water is the most, model mesh sheet relatively basic heavy Measure the biggest.The power of lifting relatively of 1.0 is defined as dry solids content drag mesh sheet relatively basic heavy in 100% weight This model mesh sheet is kept to float on the first and second bottom blow boxs 26,32 respectively with stationary mode when amount is 1.0 needed above Lift power.

In figure 6, power is lifted in Y-axis instruction relatively, and the downside of X-axis instruction mesh sheet 18 respectively with corresponding blow box 26, Average distance between the upper side 44,54 of 32 or height H1 and H3.Curve " 26 " indicates the relative of the first bottom blow box 26 Lift the relation between power and average distance H1, and curve " 32 " indicates the power of relatively lifting of the second bottom blow box 32 with flat All relations between H3.Returning to relatively lift the definition of power, from curve " 26 ", the power of relatively lifting of 1.0 is by right The average distance H1 of Ying Yuyue 1.3 millimeters.Therefore, if having the relative base of 1.0 under the dry solids content of 100% weight The above-mentioned model mesh sheet of this weight is exposed to the power of relatively lifting of 1.0, then it will be with stationary mode " floating " in first time Above portion's blow box 26 at the average distance H1 of 1.3 millimeters.This model mesh sheet has under the dry solids content of 50% weight The relatively basic weight of 2.0.In order to make this mesh sheet with stationary mode " floating ", it would be desirable to the power of relatively lifting of 2.0.Again observe Curve " 26 ", it appeared that the average distance H1 of about 0.8 millimeter is corresponding to the power of relatively lifting of 2.0.Typically, by blow box 26, every square metre of horizontal net sheet area and the air mass flow in the unit interval of 32 supplies would correspond to 500 to 2000m³/(m², h).This flow is the actual flow advanced towards mesh sheet 18.The gap S formed between blow box is contained in the meter of mesh sheet area In calculation, it is meant that the flow from the face of each blow box will typically exceed 10% in the case of not ligament S and arrive 25%。

According to an example, when by the first dry section 4, the dry solids content of model mesh sheet will be typically from correspondence Initial 50% weight in relatively basic weight 2.0 increases in the end of the first dry section 4 corresponding to relatively basic weight About 70% weight of 1.4, this is owing to moisture is by the effect from mesh sheet 18 dry out.Observe the first bottom blow box 26 of Fig. 6 Curve " 26 ", it is clear that the power of lifting relatively of 2.0 would correspond to the height H1 of about 0.8 millimeter.Therefore, the first dry section 4 it is adjacent to Starting point model mesh sheet 18 and the first bottom blow box 26 between equilibrium distance H1 be about 0.8 millimeter, because in this distance At H1, the relatively basic weight of mesh sheet 18 balances each other with the relative power of lifting of bottom blow box 26.If mesh sheet 18 will be the most remote Move from the first bottom blow box 26, such as, move to distance H1 of 2 millimeters, then the first bottom blow box 26 by applying about- The negative power of relatively lifting of 0.5, i.e. relative fixation, this will drag down mesh sheet 18.If mesh sheet 18 will the most downwardly First bottom blow box 26 moves, such as, move to distance H1 of 0.5 millimeter, then the first bottom blow box 26 is by applying about The positive power of relatively lifting of 3.5, this will force mesh sheet 18 upwards.Therefore, mesh sheet 18 is fixed at equilibrium distance H1, and cannot Move, because lifting force or bed knife will bring back to equilibrium distance mesh sheet away from this equilibrium distance easily.It is dried first The end in district 4, the relatively basic weight of 1.4 will be would be about 1.1 by equilibrium distance H1 when relatively lifting dynamic balance of 1.4 Millimeter.

Additionally, continuation above example, when by the second dry section 6, the dry solids content of mesh sheet 18 will typically from Initial 70% weight corresponding to relatively basic weight 1.4 increases in the end of the second dry section 6 corresponding to relatively basic heavy About 90% weight of amount 1.1, this is owing to moisture is by the effect of dry out from mesh sheet 18.Observe the second bottom blow box of Fig. 6 The curve " 32 " of 32, it is clear that by with 1.4 relatively basic balanced 1.4 the relative power of lifting would correspond to about 4.5 milli The height H3 of rice.Therefore, the balance being adjacent between starting point mesh sheet 18 and the second bottom blow box 32 of the second dry section 6 away from It is about 4.5 millimeters from H3.If mesh sheet 18 moves being upwardly and away from the second bottom blow box 32 temporarily, such as, move to 6.5 Distance H3 of millimeter, then will cause relatively lifting power and be reduced to about 1.0 the most smaller, it is meant that make mesh sheet 18 decline downwards directly Reach till relatively lifting power corresponding to relatively basic weight enough.If mesh sheet 18 will the most downwardly second time Portion's blow box 32 moves, such as, move to distance H3 of 3 millimeters, then the second bottom blow box 32 will apply one corresponding to about The positive power of relatively lifting of 2.5, this will force mesh sheet 18 upwards.Therefore, mesh sheet 18 by " floating " at equilibrium distance H3, but from The equilibrium distance H3 that the minor fluctuations occurred at equilibrium distance will cause quite appropriate power that mesh sheet 18 brings back to it.Second The end of dry section 6, the relatively basic weight of 1.1 be would be about 6.0 by equilibrium distance H3 when relatively lifting dynamic balance of 1.1 Millimeter.

Fig. 7 be a chart and illustrate mesh sheet 18 be dried with first respectively the first bottom blow box 26 of platen 24 with And the second relative thermal transmission being dried between the second bottom blow box 32 of platen 30.In trunnion axis X-axis, there is shown mesh sheet The downside of 18 average distance respectively and between the upper side 44,54 of corresponding blow box 26,32 or height H1 and H3.In vertical axes In Y-axis, there is shown transmit from the relative thermal of corresponding blow box 26,32 to mesh sheet 18.Relative thermal is delivered in the second bottom blowing The average distance H3 of case 32 is when 5 millimeters to be 1.0, and every other relative thermal delivery value is to calculate relative to this heat transfer 's.

The example be given continuing with Fig. 6, can wander back to, mesh sheet 18 and the first bottom blow box of the first dry section 4 The equilibrium distance H1 between 26 starting point in this district 4 is about 0.8 millimeter and is about 1.1 millimeters in the end in this district 4. Observe the curve " 26 " of the first bottom blow box 26 of Fig. 7, it is clear that the relative thermal transmission of about 0.63 would correspond to 0.8 to 1.1 millis The height H1 of rice.Additionally, can wander back to from combining the example that Fig. 6 provides, mesh sheet 18 and the second bottom of the second dry section 6 The equilibrium distance H3 between blow box 32 starting point in this district 6 is about 4.5 millimeters, and is about 6.0 in the end in this district 6 Millimeter.Observe the curve " 32 " of the second bottom blow box 32 of Fig. 7, it is clear that the relative thermal transmission of about 0.98 would correspond to about 4.5 The height H3 of millimeter, this is the typicalness of the starting point at the second dry section 6, and the relative thermal of about 1.01 transmits correspondence In the height H3 of about 6.0 millimeters, this is the typicalness of the end at the second dry section 6.

According to Fig. 7 and above example, it is clear that the heat transfer of the second dry section 6 is more much higher than the heat transfer of the first dry section 4. In the case of without being bound by any theory, it will be seen that, it appears that the preferable heat transfer of the second dry section 6 is attributed to following two The individual fact: the relatively long distance between mesh sheet 18 with corresponding blow box 26,32 is of value to heat transfer, this distance at least up to about 10 milli Rice；And in the case of the dry air of heat mainly blows upwardly toward mesh sheet 18 on vertical direction VU, the second bottom is blown Bellows 32 seem therefore more effective than the first bottom blow box 26 of the dry air blowing some heat in an inclined manner.Another Aspect, the first dry section 4 provides the more stable control of the advance to mesh sheet 18, thus causes less tensile force to be applied to In mesh sheet 18.The hot strength of mesh sheet 18 tends to the reduction of moisture and increases.Therefore, mesh sheet 18 is being adjacent to Fig. 1 At the entrance 20 of the drying baker 1 of middle diagram the most weak, and be adjacent at the outlet 22 of drying baker 1 the strongest.Therefore In the first dry section 4, mesh sheet is dried under low extended state in the case of the path of the quite stable of mesh sheet, until Till mesh sheet has been dried to the dry solids content of e.g., from about 55% to 80%.Subsequently, higher stretching has been obtained in mesh sheet 18 strong In the case of degree, mesh sheet 18 in the second dry section 6 stretching increase but also in the case of high heat transfer It is dried, so that it is effective for being dried.

See Fig. 1 to describe drying baker 1 and include the first dry section the 4, second dry section 6 and cooling zone 8.Will Solving, many alternate embodiments are possible.For example, it is also possible in the case of need not cooling, design has first Dry section 4 and the second dry section 6 still do not have the drying baker of cooling zone.

As described above, the 3rd bottom blow box 38 of cooling zone 8 can have with Fig. 3 in diagram the first bottom blow What bellows 26 were identical be typically designed or with the second identical being typically designed of bottom blow box 32 of diagram in Fig. 5.

Use and there is the threeth bottom blow box 38 that be typically designed identical with the second bottom blow box 32 of diagram in Fig. 5 There is the advantage that heat transfer is high, be similarly to combine depicted and described in Fig. 7 for illustrated by the second bottom blow box 32 Heat transfer.Therefore, the cooling in cooling zone 8 becomes the most effective.

Use and there is the threeth bottom blow box 38 that be typically designed identical with the first bottom blow box 26 of diagram in Fig. 3 Have the advantage that the mesh sheet 18 leaving drying baker 1 via outlet 22 is stablized, there is minimum vertically moving.This for The upstream device being disposed the drying mesh sheet 18 leaving drying baker 1 can be favourable, this equipment for example, mesh sheet position Put control unit, mesh sheet sickle etc..

Therefore, if heat transfer has limit priority in cooling zone 8, then use the general type disclosed in Fig. 5 The 3rd bottom blow box 38 that is configured as will be suitable.On the other hand, if mesh sheet stability has in cooling zone 8 High priority, then the 3rd bottom blow box 38 that is configured as using the general type disclosed in Fig. 3 will be suitable.Another Individual selection is to arrange have the cold of one or more cooling slab 36 with the bottom blow box 38 of design as illustrated in Figure 5 But district 8 is to obtain effectively cooling, the upstream of last lucky outlet 22 at drying baker 1 of cooling slab 36 of this cooling zone 8, This last cooling slab possesses the 3rd bottom blow box 38 of the design of the general type disclosed in Fig. 3, thus just exists Mesh sheet 18 obtains good mesh sheet stability before leaving drying baker 1.If mesh sheet stability has limit priority, but is dried Case does not have cooling zone, then can be at arranged downstream the 3rd dry section of the second dry section.This 3rd dry section will typically Have and be similar to the first of the first dry section 4 and be dried the multiple dry platen of platen 24 and have high for generation mesh sheet stable First bottom blow box 26 of property.This 3rd dry section will typically have the dry platen of only one to four.

It will be appreciated that many variants of examples described above are possible within the scope of the appended claims 's.

Drying baker 1 is had been described there are 19 dry platens altogether.In these dry platens, 8 (are dried The 42% of platen sum) belong to the first dry section 4, and 11 (being dried the 58% of platen sum) belong to the second dry section 6.At tool Having in the drying baker of two dry sections 4,6, typically, the 10%-70% being dried platen sum will belong to the first dry section 4 and have First bottom blow box 26 of type shown in standby Fig. 3, and correspondingly, typically, the 30%-90% being dried platen sum will belong to In the second dry section 6 and the second bottom blow box 32 of possessing type shown in Fig. 5.Normally, the first dry section 4 will only have Have to make mesh sheet 18 obtain the dry platen of the number required for hot strength enough for the second dry section 6.? In the case of there is the 3rd dry section, the even the 4th dry section, those dry sections normally can reduce being dried of the second dry section The number of platen.Typically, the first dry section 4 will include that at least two first is dried platen 24.

" eyelid perforation " class that first bottom blow box 26 will be provided with in WO97/16594 disclose is had been described The apsacline opening 46 of type.It will be appreciated that apsacline opening 46 can also have the design of replacement.US5,471,766 drapes over one's shoulders Reveal the example of this alternate design.In Fig. 6 of US5,471,766, disclose that to have a center V-arrangement in upper side recessed The blow box of groove.Defining multiple hole on multiple sidewalls of this groove, this some holes tilts relative to the upper side of blow box.This The apsacline opening planting " groove walls perforation " type can be as apsacline opening for the first bottom blow box.

It will be appreciated that different types of fixed pattern blow box can be used in drying baker.Therefore, the first dry section can To possess the first bottom blow box 26 of type shown in Fig. 3.Therefore, in the first dry section, will appear from relatively large fixing Power.Second dry section can possess and is similar to type shown in Fig. 3 but has the first bottom blow box of relatively low bed knife.This Relatively low bed knife can such as by increasing the diameter of opening 48 of Second Type and/or number so that less dry sky Gas is realized by eyelid perforation 46.This will produce relatively low bed knife, and this may remain acceptable, because mesh sheet is The hot strength of increase is obtained in the first dry section.Then the 3rd dry section starts, this 3rd dry section have Fig. 4 and The dry platen of type shown in 5 and the second bottom blow box.Therefore, it can arrange different types of blowing in various manners Case, in order to obtain the appropraite condition relevant to the bed knife of the specific mesh sheet 18 being dried in drying baker 1 and heat transfer.Cause This, drying baker will be provided with two or more dry section, typically 2 to 10 dry sections.

Having illustrated each top blow box 34 is vertically to be arranged on the bottom blow box 32 of correspondence Side.It will be appreciated that, it is also possible to use other arrangements of upper and lower blow box.This example arranged that substitutes is institute The alternate arrangement of meaning, above each of which top blow box 34 gap S between two neighbouring bottom blow boxs 32 Between two parties.

Being hereinbefore described opening 48,60 is circular port.It will be appreciated that other shapes in addition to circular port are also Possibly serve for opening.For example, opening 48,60 can be square, rectangle, triangle, ellipse, pentagon, hexagon Etc. shape.

It is hereinbefore described the first dry section 4 and includes the first bottom blow box 26, and the second dry section 6 includes second Bottom blow box 32.It will be appreciated that it is possible for mixing multiple blow box in corresponding dry section.So that it takes up a position, for example, the One dry section 4 can include the second bottom blow box 32 of up to 25%, and the second dry section 6 can include up to 25% One bottom blow box 26.And, the first and second dry sections can include other kinds of bottom blow box.Preferably, In the first dry section 4, the bottom blow box of at least 75% should be the first bottom blow box 26, in the second dry section 6, extremely The bottom blow box of few 75% should be the second bottom blow box 32.According to an embodiment, dry platen can include only a kind of The corresponding bottom blow box of type and top blow box.So that it takes up a position, for example, at least one of the first dry section 4 is first dry Dry platen 24 can only include the first bottom blow box 26 and the first top blow box 28, and at least the one of the second dry section 6 Individual second is dried platen 30 can only include the second bottom blow box 32 and the second top blow box 34.It is still possible that citing For, the Part I being dried platen includes the first bottom blow box 26, and the Part II bag subsequently of this dry platen Include the second bottom blow box 32.In this case, this Part I being dried platen may belong to the first dry section 4, and And dry platen this subsequently Part II may belong to the second dry section 6.

Claims (11)

1., for being dried a device for a cellulose pulp mesh sheet (18) in a drying baker (1), this drying baker includes Multiple blow boxs (26,32), these blow boxs (26,32) can operate and blow sky for towards this cellulose pulp mesh sheet (18) Gas, thus it is dried paper pulp according to unsettled mesh sheet principle,

It is characterized in that, this drying baker (1) includes first dry section (4) and second dry section (6), this first be dried District includes the multiple first bottom blow boxs (26) being arranged to for supporting this mesh sheet (18), and this second dry section includes being pacified Lining up the multiple second bottom blow boxs (32) for supporting this mesh sheet (18), wherein these first bottoms blow box (26) are different In these the second bottoms blow box (32), wherein these first bottoms blow box (26) possess multiple apsacline opening (46), this A little apsacline openings are adapted at least 30% ejection of the air by being fed to these the first bottoms blow box (26), and its In these second bottoms blow box (32) possess multiple non-inclined type opening (60), these non-inclined type openings are adapted to supply Should arrive at least 75% ejection of the air of these the second bottoms blow box (32), wherein said apsacline opening refers to open from those At least the 25% of the air that mouth blows is that the upper side with described first bottom blow box becomes the angle less than 60 ° to blow, and And described non-inclined type opening refers to that at least 80% from the air that those openings blow is and described second bottom blow box Upper face become the angle of at least 70 ° to blow.

2. device as claimed in claim 1, wherein this first dry section (4) is arranged at the upstream of this second dry section (6).

3. device as claimed in claim 1, at least a part of which is for corresponding bottom blow box and this cellulose pulp mesh sheet (18) for the certain distance (H3, H1) between, the power of relatively lifting of these the second bottoms blow box (32) higher than these first The power of relatively lifting of bottom blow box (26).

4. device as claimed in claim 3, if the bottom blow box of at least a part of which correspondence (32,26) and this cellulose pulp Distance (H3, H1) between mesh sheet (18) is 2 to 8 millimeters, and the power of relatively lifting of these the second bottoms blow box (32) is just higher than The power of relatively lifting of these the first bottoms blow box (26).

5. the device as described in any one in claim 1-4, wherein this drying baker (1) include several dry platens (24, 30), each dry platen includes multiple bottoms blow box (26,32) and is adapted for doing at this in this mesh sheet (18) When advancing along horizontal route at one certain height of dry case (1) being dried this mesh sheet, wherein this first is dried District (4) includes the 10%-70% of the sum of the dry platen (24,30) of this drying baker (1).

6. the device as described in any one in claim 1-4, wherein this drying baker (1) farther include to be arranged in this second One cooling zone (8) in the downstream of dry section (6), this cooling zone (8) include described first bottom blow box (26).

7., for the method that a cellulose pulp mesh sheet (18) is dried, it is by by means of multiple blow box courts Blowing air to this cellulose pulp mesh sheet (18) thus be dried paper pulp according to unsettled mesh sheet principle, the feature of the method exists In:

Making this mesh sheet (18) advance through first dry section (4), it is many that this first dry section includes supporting this mesh sheet (18) Individual first bottom blow box (26), and then

Making this mesh sheet (18) advance through second dry section (6), it is many that this second dry section includes supporting this mesh sheet (18) Individual second bottom blow box (32), these second bottoms blow box (32) are different from these the first bottoms blow box (26), wherein These first bottoms blow box (26) possess multiple apsacline opening (46), and these apsacline openings are adapted to be fed to this At least 30% ejection of the air of a little first bottom blow boxs (26), and wherein these second bottoms blow box (32) possess many Individual non-inclined type opening (60), these non-inclined type openings are adapted to the sky by being fed to these the second bottoms blow box (32) At least 75% ejection of gas, wherein said apsacline opening refers to that at least the 25% of the air blowed from those openings is with described The upper side of the first bottom blow box becomes the angle less than 60 ° to blow, and described non-inclined type opening refers to open from those In the air that mouth blows at least 80% is that the upper face with described second bottom blow box becomes the angle of at least 70 ° to blow 's.

8. method as claimed in claim 7, wherein average between this mesh sheet (18) and these the second bottoms blow box (32) Distance (H3) is more than the average distance (H1) between this mesh sheet (18) and these the first bottoms blow box (26).

9. method as claimed in claim 7, wherein these second bottoms blow box (32) and these the first bottom blow boxs (26) compare and be applied with higher heat transfer to this mesh sheet (18).

10. the method as according to any one of claim 7 to 9, is wherein fed to the total of these the first bottoms blow box (26) At least the 30% of air mass flow is that the corresponding upper side (44) with those the first bottom blow boxs (26) becomes the angle less than 60 ° (α) and from these first bottoms blow box (26) blow out, and be wherein fed to the total of these the second bottoms blow box (32) At least the 75% of air mass flow be corresponding upper side (54) with those the second bottom blow boxs (32) become at least 75 ° angle and Blow out from these second bottoms blow box (32).

11. methods as according to any one of claim 7 to 9, wherein this mesh sheet (18) is at these the first bottom blow boxs (26) average distance (H1) place of 0.2 to 3 millimeters, top advances, and makes this mesh sheet (18) at these the second bottom blow boxs (32) average distance (H3) place of 4 to 15 millimeters, top advances.