EP4343060A2 - Stud for a doctor blade holder in a fiber web machine and doctor blade holder assembly for a fiber web machine - Google Patents
Stud for a doctor blade holder in a fiber web machine and doctor blade holder assembly for a fiber web machine Download PDFInfo
- Publication number
- EP4343060A2 EP4343060A2 EP23198694.4A EP23198694A EP4343060A2 EP 4343060 A2 EP4343060 A2 EP 4343060A2 EP 23198694 A EP23198694 A EP 23198694A EP 4343060 A2 EP4343060 A2 EP 4343060A2
- Authority
- EP
- European Patent Office
- Prior art keywords
- rail structure
- doctor blade
- blade holder
- stud
- assembly according
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
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- 239000000835 fiber Substances 0.000 title claims abstract description 15
- KJLPSBMDOIVXSN-UHFFFAOYSA-N 4-[4-[2-[4-(3,4-dicarboxyphenoxy)phenyl]propan-2-yl]phenoxy]phthalic acid Chemical compound C=1C=C(OC=2C=C(C(C(O)=O)=CC=2)C(O)=O)C=CC=1C(C)(C)C(C=C1)=CC=C1OC1=CC=C(C(O)=O)C(C(O)=O)=C1 KJLPSBMDOIVXSN-UHFFFAOYSA-N 0.000 claims description 5
- 229910000906 Bronze Inorganic materials 0.000 claims description 4
- 239000010974 bronze Substances 0.000 claims description 4
- KUNSUQLRTQLHQQ-UHFFFAOYSA-N copper tin Chemical compound [Cu].[Sn] KUNSUQLRTQLHQQ-UHFFFAOYSA-N 0.000 claims description 4
- 229910001220 stainless steel Inorganic materials 0.000 claims description 4
- 239000010935 stainless steel Substances 0.000 claims description 4
- 239000002184 metal Substances 0.000 claims description 3
- 239000007787 solid Substances 0.000 claims description 2
- 238000009434 installation Methods 0.000 description 7
- 238000012423 maintenance Methods 0.000 description 6
- 238000010276 construction Methods 0.000 description 2
- 239000011152 fibreglass Substances 0.000 description 2
- 239000011800 void material Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 230000000712 assembly Effects 0.000 description 1
- 238000000429 assembly Methods 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 230000005923 long-lasting effect Effects 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 230000008685 targeting Effects 0.000 description 1
Images
Classifications
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21G—CALENDERS; ACCESSORIES FOR PAPER-MAKING MACHINES
- D21G3/00—Doctors
- D21G3/005—Doctor knifes
Definitions
- the invention relates to a stud for a doctor blade holder in a fiber web machine, the stud having a body with a flange.
- the invention also relates to a doctor blade holder assembly for a fiber web machine.
- the height of the known doctor blade holder assembly is big.
- the high assembly needs space and increases forces straining the doctor blade holder and the studs.
- the known rail structure is of metal with fiberglass segments.
- the fiberglass is prone to cracking especially under impact loads, and it deteriorates over time.
- the stud itself has several parts and it requires the use of a special tool to install. This makes it difficult for maintenance when the tool is not available.
- the stud has rotating components which are weak. They will break off with time and when entering the rail structure the sharp corners cause damage to the rotating elements. During use the studs will jam to the rail structure and it is hard to slide out the doctor blade holder.
- the characteristic features of the stud according to this invention are stated in the accompanying Claim 1.
- Another object of the invention is to provide a novel doctor blade holder assembly for a fiber web machine which assembly is simple and compact but has rigid support for the doctor blade holder and can be utilized in various positions and with different doctor blade holders. The assembly can be made low, and it is easy to maintain.
- the characteristic features of the doctor blade holder assembly according to this invention are stated in the accompanying Claim 5.
- the stud and other parts of the assembly have unique properties. In this way, the doctor blade holder assembly functions accurately and is long lasting. With new kinds of parts, the doctor blade holder assembly remains simple but robust, and it is easy to slide in and out.
- Figure 1 shows one doctor blade holder assembly according to the invention adapted to the vicinity of a surface 10 to be doctored.
- the doctor blade holder assembly is especially for a fiber web machines such as paper, board, and tissue machines.
- one doctor blade 11 is arranged to a doctor blade holder 12 fixed to a doctor beam 13.
- other kinds of support structures for the doctor blade holder may be used and generally the support is called as a doctor back.
- the surface 10 rotates counterclockwise.
- the surface can be, for example, the surface of a drying cylinder. Then the doctor blade keeps the surface clean.
- the doctor blade holder assembly is also suitable for doctoring polymer coated rolls, belts, and transfer belts as well as open-surfaced rolls.
- a fiber web machine such as a paper or board or tissue machine
- open-surfaced rolls are used for several varied reasons.
- the shell is perforated for leading a vacuum effect from the inside of the roll to the outside of it.
- the doctored rolls have some void volume for water to escape.
- the void volume can be grooves, blind holes and/or through holes.
- the dry end and finishing part of the machine most of the doctored rolls have a smooth surface.
- the holes make the shell open-surfaced.
- grooved rolls are also used, in which the shell surface is grooved mainly for improving dewatering.
- a suction roll with a grooved surface also exists, the shell of which is provided with both holes and grooves.
- blind bores for example, can be used.
- Soft coatings are also used in the rolls while belts and transfer belts are soft surfaced by their nature.
- the surface of a belt for example, can be grooved.
- the doctor blade removes water and impurities from the surface. Also, the doctor blade may remove the fiber web off the surface. In practice, in the center roll doctoring is crucial. So, there are even two consequent doctor blade at one roll.
- the doctor blade holder is attached to the doctor back with several screws.
- a rail structure 14 is used together with studs.
- the stud is for a doctor blade holder assembly in a fiber web machine.
- One stud 15 is shown in Figure 2a .
- the stud 15 has a body 16 with a flange 17.
- the body is a single piece having a form for a standard tool.
- the form includes two opposite flats 18 arranged in the flange 17 ( Figure 2b ).
- the body can be hold by a spanner or adjustable spanner, for example.
- the stud is positioned so that the flats 18 are mainly crosswise in relation to the rail structure 14 ( Figures 4a and 4b ).
- the studs will stay inside the rail structure with clearances as designed.
- the stud 15 in one piece is shown in Figure 2c .
- the body 16 of the stud 15 has a threaded center boring 19 in center and circular shape with aforementioned flats 18 for assembly and disassembly using standard tools.
- the center boring 19 is for the machine screw 20 attaching the doctor blade holder which is explained in more detail later.
- the plain stud with the flange would be enough to attach the doctor blade holder to the rail structure.
- a rotating piece 21 arranged around the body 16. This rotating piece will contact smoothly with the rail structure but simultaneously aid the sliding function.
- the rotating piece 21 is a tubular sleeve made of bronze or stainless steel. Then the stud will have more durability and longer life than with the known studs.
- the body itself is of stainless steel 316, for example.
- the stud will by aligned to the rail structure by aid of the flange and the rotating piece. So there are small clearances, and the vibrations of the doctor blade holder will be avoided.
- the body 16 has a circumferential shoulder 22 at an end 23 opposite to the flange 17.
- a corresponding hole is in the doctor blade holder, like in the tray or base plate 24 in Figures 3a and 3b .
- the stud will be firmly aligned with the doctor blade holder.
- the doctor blade holder assembly is for a fiber web machine, and it has a doctor blade holder 12 arranged movable to a rail structure 14 with a plurality of consecutive studs 15 having a body 16 with a flange 17. With this kind of construction the whole doctor blade holder can be pulled out in cross machine direction for maintenance and cleanup, for example. On the other hand, during installation, the rail structure is first attached to the doctor back. Then the doctor blade holder equipped with studs is slid in in cross machine direction.
- the majority of the studs are studs according to the present invention.
- the modern doctor blade holder assembly includes a doctor blade holder 12 arranged pivotably by a pivot rod 25 supported to brackets 26. In this way, only the doctor blade holder pivots with the doctor blade.
- the doctor beam 13 is a rigid structure. The doctor beam 13 is supported at its ends and there are setting means for adjusting the angle of the doctor beam 13 (not shown) . The actual loading of the doctor blade is done by pivoting the doctor blade holder. The doctor beam forms the doctor back.
- FIGS 3a and 3b show the doctor blade holder assembly, where the doctor blade holder 12 also includes loading fingers 27, which are fixed to a top plate 28. Then there are top brackets 29 also fixed to the top plate 28. These top brackets are like the bracket 26 as bolted to the studs. There is also a pivot rod passed through both brackets. And more, between the studs 15 and the brackets 26 there is a base plate 24 holding two loading tubes 30 in place. Thus the top plate and the doctor blade installed thereto can pivot. By the loading tubes, the doctor blade is pressed against the surface or lifted up for maintenance. Then there a jaw part 31 also screwed to the top plate 28. The doctor blade 11 is supported by a blade holder 12, which includes a top plate 28 and a jaw part 31. Here the jaw part 31 is a separate piece screwed to the top plate 28. In other words, loading fingers are redundant.
- the body 16 has outer dimensions according to the rail structure 14. Especially, the distance between the shoulder and the flange equals to rail structure ( Figures 3a and 3b ). This eliminates movements in the vertical direction of the stud. Simultaneously, the diameter of the rotating element equals to the rail structure in vertical direction. Thus the doctor blade holder will stay firmly supported without big gaps and any wiggling.
- Figure 3c disclosed one rail structure 14 according to the invention.
- the rail structure 14 is of solid metal.
- the cross section of the rail structure 14 is shown in Figure 2c .
- This kind of rail structure is also called as T-rail.
- bronze, or stainless steel is used for strength, durability, and long life.
- the rail structure 14 has an entry area 32 with funnel shape. Sharp edges are thus avoided by bevels and rounded corners. This makes it easier to align the doctor blade holder for installation and prevents rotating piece damage.
- Figure 4a only the left side of the rail structure is beveled, which is enough for smooth operation.
- the rail structure has even more new features.
- the rail structure 14 has counter bored slots 33 for back bolts 34. With the back bolts the rail structure is attached the doctor back.
- One back bolt 34 is shown in Figure 2c with dotted line. These counter bored slots allow misalignment on doctor back bolt pattern.
- the rail structure according to the invention can be easily installed to old doctor assemblies even the holes for back bolt are not precisely positioned in cross-machine direction.
- the rail structure 14 itself has innovative design.
- the rail structure 14 includes two rail parts 35 and 36 arranged apart from each other. The cross sections of both parts are shown in Figure 2d . With separate parts more back bolts are needed, but the height of the rail structure is much lower than previous. This reduced stresses targeting to the studs. Also, the parts will be attached more firmly to the doctor back. In principle the parts could be identical which would simply the manufacturing. However, advantageously one or both of the parts 35, 36 is installed on a doctor back 13 by form guiding. As shown in Figure 2d , the left side part 35 has a protrusion 37 which bears to the tip 38 of the doctor back 13. The protrusion will keep the part well aligned and straight when the back bolts are installed.
- doctor back 13 has an accurate machining 39 forming an elevated edge 40 for the second part 36.
- the second part 36 is well aligned and straight when the back bolts 34 are installed.
- This kind of rail structure suits well in new installations where the doctor back is made for the assembly according to the invention.
- an old doctor back may be machined if the assembly is rebuilt.
- the rail structure 14 consists of several consecutive segments 41 with interlocking design therebetween. Segments with one length may be manufactured and then install segments consecutively as many as needed. If necessary, one or more segments are shortened to adjust to the total length.
- the interlocking design ensures accurate alignment of the segments when assembled.
- Figure 3d shows one embodiment where on the left is a snick 42 and on the right is a corresponding notch 43. In the two-part rail structure this kind of design is not necessary, since the parts will be aligned by form guiding to the doctor back as explained above. Although, interlocking design may be utilized.
- the doctor blade holder In principle, there are studs over the length of the doctor blade holder. Thus the doctor blade holder is firmly supported.
- a slide bar 44 equipped with a handle 45 outside the rail structure 14 ( Figures 4a and 4b ) .
- the slide bar 44 is dimensioned in view of the rail structure. So extra clearances are avoided, and the support remains also at the end of the doctor blade holder.
- the handle 45 makes it possible to pull out the doctor blade holder by hand or using some pulling device.
- the slide bar 44 is mounted to the doctor blade 12 holder with two machine screws 20.
- the handle 45 is a large hole in the end of the slide bar to allow for connecting heavy duty pull out hardware like shackle or like.
- the slide bar has even more new features.
- the slide bar 44 has several consecutive holes 47 for a lock down bolt 48.
- the lock down bolt prevents the doctor blade holder from moving in the cross-machine direction while in operation.
- the drilled and tapped holes are on the end of the slide bar before the handle.
- This construction allows for more cross machine adjustment of the doctor blade holder.
- For the lock down bolt there is a threaded hole 49 at the end of the rail structure 14, see Figure 3c . Alternative, corresponding hole would be on the doctor back in the embodiments like in Figures 3b and 4a .
- a transfer equipment 50 is integrated into the slide bar and rail structure to facilitate initial sliding movement and fine tuning of the cross-machine position to insert the lock down bolt.
- a fork 51 is bolted to the rail structure 14.
- a threaded block 52 bolted to the slide bar 44.
- an adjustment screw 53 equipped with a lock nut 54.
- the transfer equipment can be used to adjust the doctor blade holder during the installation.
- the adjustment screw as well the lock nut may be rotated with standard tools.
- the transfer equipment can be installed on the other side of the rail structure.
- the doctor blade 11 as well as the doctor assembly has a length of several meters, from 1 to 11 meter extending in cross-machine direction.
- the doctor blade has a width from 5 to 20 centimeters extending in machine direction.
- the stud according to the invention is simple but robust. With aid of other surprising features of the doctor blade holder, the installation and maintenance of the doctor blade holder assembly is easy and quick. At the same time, the doctor blade holder assembly is low in structure and is vibration-free. Also it is easy the maintain the doctor blade holder assembly, and it will suit for new installation and to retrofits.
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- Paper (AREA)
- Preliminary Treatment Of Fibers (AREA)
Abstract
Description
- The invention relates to a stud for a doctor blade holder in a fiber web machine, the stud having a body with a flange. The invention also relates to a doctor blade holder assembly for a fiber web machine.
- In order to facilitate the maintenance of the doctor blade holder assembly, a doctor blade holder with sliding function has been developed. US-patent application number
US20020153114A1 discloses such an assembly. Here the sliding function is implemented with a rail structure and multiple studs supporting the doctor blade holder and sliding inside the rail structure. In this way, the whole doctor blade holder can be slid out for maintenance. Similarly, the doctor blade holder can be slid in. - The height of the known doctor blade holder assembly is big. The high assembly needs space and increases forces straining the doctor blade holder and the studs. The known rail structure is of metal with fiberglass segments. The fiberglass is prone to cracking especially under impact loads, and it deteriorates over time. The stud itself has several parts and it requires the use of a special tool to install. This makes it difficult for maintenance when the tool is not available. The stud has rotating components which are weak. They will break off with time and when entering the rail structure the sharp corners cause damage to the rotating elements. During use the studs will jam to the rail structure and it is hard to slide out the doctor blade holder.
- It is an object of the invention to provide a novel stud for a doctor blade holder in a fiber web machine with easier exploitation and improved durability. The characteristic features of the stud according to this invention are stated in the accompanying Claim 1. Another object of the invention is to provide a novel doctor blade holder assembly for a fiber web machine which assembly is simple and compact but has rigid support for the doctor blade holder and can be utilized in various positions and with different doctor blade holders. The assembly can be made low, and it is easy to maintain. The characteristic features of the doctor blade holder assembly according to this invention are stated in the accompanying Claim 5. The stud and other parts of the assembly have unique properties. In this way, the doctor blade holder assembly functions accurately and is long lasting. With new kinds of parts, the doctor blade holder assembly remains simple but robust, and it is easy to slide in and out.
- The invention is described below in detail by referring to the enclosed drawings which illustrate some of the embodiments of the invention, in which
- Figure 1
- shows a doctor blade holder assembly according to the invention adapted to the vicinity of a surface to be doctored,
- Figure 2a
- shows a stud according to the invention in 3D,
- Figure 2b
- shows the stud seen from below,
- Figure 2c
- shows a cross section of the parts of the stud together with one embodiment of the rail structure according to the invention,
- Figure 2d
- shows a cross section of another embodiment of the rail structure according to the invention without the stud,
- Figure 3a
- shows a cross section of one embodiment of the doctor blade holder assembly according to the invention,
- Figure 3b
- shows a cross section of another embodiment of the doctor blade holder assembly according to the invention,
- Figure 3c
- shows a rail structure according to the invention seen from above,
- Figure 3d
- shows an enlargement of the rail structure of
Figure 3c , - Figure 4a
- shows the rail structure according to the invention equipped with a slide bar,
- Figure 4b
- shows another rail structure according to the invention equipped with the slide bar and a transfer equipment.
-
Figure 1 shows one doctor blade holder assembly according to the invention adapted to the vicinity of asurface 10 to be doctored. The doctor blade holder assembly is especially for a fiber web machines such as paper, board, and tissue machines. Here onedoctor blade 11 is arranged to adoctor blade holder 12 fixed to adoctor beam 13. Also other kinds of support structures for the doctor blade holder may be used and generally the support is called as a doctor back. Here thesurface 10 rotates counterclockwise. The surface can be, for example, the surface of a drying cylinder. Then the doctor blade keeps the surface clean. The doctor blade holder assembly is also suitable for doctoring polymer coated rolls, belts, and transfer belts as well as open-surfaced rolls. In a fiber web machine, such as a paper or board or tissue machine, open-surfaced rolls are used for several varied reasons. In a suction roll, for example, the shell is perforated for leading a vacuum effect from the inside of the roll to the outside of it. In other words, in the wet end of the machine, the doctored rolls have some void volume for water to escape. The void volume can be grooves, blind holes and/or through holes. Whereas in the dry end and finishing part of the machine most of the doctored rolls have a smooth surface. The holes make the shell open-surfaced. On the other hand, grooved rolls are also used, in which the shell surface is grooved mainly for improving dewatering. A suction roll with a grooved surface also exists, the shell of which is provided with both holes and grooves. In addition to or instead of grooves, blind bores, for example, can be used. Soft coatings are also used in the rolls while belts and transfer belts are soft surfaced by their nature. In addition, the surface of a belt, for example, can be grooved. The doctor blade removes water and impurities from the surface. Also, the doctor blade may remove the fiber web off the surface. In practice, in the center roll doctoring is crucial. So, there are even two consequent doctor blade at one roll. - As it simplest, the doctor blade holder is attached to the doctor back with several screws. Here, instead, a
rail structure 14 is used together with studs. Generally, the stud is for a doctor blade holder assembly in a fiber web machine. Onestud 15 is shown inFigure 2a . Thestud 15 has abody 16 with aflange 17. According to the invention, the body is a single piece having a form for a standard tool. Thus there are less parts, and the stud maybe easily installed and deinstalled with a standard tool. Here, the form includes twoopposite flats 18 arranged in the flange 17 (Figure 2b ). Thus the body can be hold by a spanner or adjustable spanner, for example. During installation, the stud is positioned so that theflats 18 are mainly crosswise in relation to the rail structure 14 (Figures 4a and 4b ). Thus the studs will stay inside the rail structure with clearances as designed. - The
stud 15 in one piece is shown inFigure 2c . Thebody 16 of thestud 15 has a threaded center boring 19 in center and circular shape withaforementioned flats 18 for assembly and disassembly using standard tools. The center boring 19 is for themachine screw 20 attaching the doctor blade holder which is explained in more detail later. - Even the plain stud with the flange would be enough to attach the doctor blade holder to the rail structure. However, there is also a
rotating piece 21 arranged around thebody 16. This rotating piece will contact smoothly with the rail structure but simultaneously aid the sliding function. Advantageously, the rotatingpiece 21 is a tubular sleeve made of bronze or stainless steel. Then the stud will have more durability and longer life than with the known studs. The body itself is of stainless steel 316, for example. - The stud will by aligned to the rail structure by aid of the flange and the rotating piece. So there are small clearances, and the vibrations of the doctor blade holder will be avoided. Here, the
body 16 has acircumferential shoulder 22 at anend 23 opposite to theflange 17. A corresponding hole is in the doctor blade holder, like in the tray orbase plate 24 inFigures 3a and 3b . Thus, the stud will be firmly aligned with the doctor blade holder. - The doctor blade holder assembly is for a fiber web machine, and it has a
doctor blade holder 12 arranged movable to arail structure 14 with a plurality ofconsecutive studs 15 having abody 16 with aflange 17. With this kind of construction the whole doctor blade holder can be pulled out in cross machine direction for maintenance and cleanup, for example. On the other hand, during installation, the rail structure is first attached to the doctor back. Then the doctor blade holder equipped with studs is slid in in cross machine direction. Advantageously, the majority of the studs are studs according to the present invention. - The modern doctor blade holder assembly includes a
doctor blade holder 12 arranged pivotably by apivot rod 25 supported tobrackets 26. In this way, only the doctor blade holder pivots with the doctor blade. In the embodiment ofFigure 1 , thedoctor beam 13 is a rigid structure. Thedoctor beam 13 is supported at its ends and there are setting means for adjusting the angle of the doctor beam 13 (not shown) . The actual loading of the doctor blade is done by pivoting the doctor blade holder. The doctor beam forms the doctor back. -
Figures 3a and 3b show the doctor blade holder assembly, where thedoctor blade holder 12 also includesloading fingers 27, which are fixed to atop plate 28. Then there aretop brackets 29 also fixed to thetop plate 28. These top brackets are like thebracket 26 as bolted to the studs. There is also a pivot rod passed through both brackets. And more, between thestuds 15 and thebrackets 26 there is abase plate 24 holding twoloading tubes 30 in place. Thus the top plate and the doctor blade installed thereto can pivot. By the loading tubes, the doctor blade is pressed against the surface or lifted up for maintenance. Then there ajaw part 31 also screwed to thetop plate 28. Thedoctor blade 11 is supported by ablade holder 12, which includes atop plate 28 and ajaw part 31. Here thejaw part 31 is a separate piece screwed to thetop plate 28. In other words, loading fingers are redundant. - Advantageously, the
body 16 has outer dimensions according to therail structure 14. Especially, the distance between the shoulder and the flange equals to rail structure (Figures 3a and 3b ). This eliminates movements in the vertical direction of the stud. Simultaneously, the diameter of the rotating element equals to the rail structure in vertical direction. Thus the doctor blade holder will stay firmly supported without big gaps and any wiggling. -
Figure 3c disclosed onerail structure 14 according to the invention. Here, therail structure 14 is of solid metal. The cross section of therail structure 14 is shown inFigure 2c . This kind of rail structure is also called as T-rail. Advantageously, bronze, or stainless steel is used for strength, durability, and long life. - As shown in
Figures 3c and4b , therail structure 14 has anentry area 32 with funnel shape. Sharp edges are thus avoided by bevels and rounded corners. This makes it easier to align the doctor blade holder for installation and prevents rotating piece damage. InFigure 4a only the left side of the rail structure is beveled, which is enough for smooth operation. - The rail structure has even more new features. First, the
rail structure 14 has counter boredslots 33 forback bolts 34. With the back bolts the rail structure is attached the doctor back. Oneback bolt 34 is shown inFigure 2c with dotted line. These counter bored slots allow misalignment on doctor back bolt pattern. In other words, the rail structure according to the invention can be easily installed to old doctor assemblies even the holes for back bolt are not precisely positioned in cross-machine direction. - Also the rail structure itself has innovative design. Now the
rail structure 14 includes tworail parts Figure 2d . With separate parts more back bolts are needed, but the height of the rail structure is much lower than previous. This reduced stresses targeting to the studs. Also, the parts will be attached more firmly to the doctor back. In principle the parts could be identical which would simply the manufacturing. However, advantageously one or both of theparts Figure 2d , theleft side part 35 has aprotrusion 37 which bears to thetip 38 of the doctor back 13. The protrusion will keep the part well aligned and straight when the back bolts are installed. Here the doctor back 13 has anaccurate machining 39 forming anelevated edge 40 for thesecond part 36. Like thefirst part 35, thesecond part 36 is well aligned and straight when theback bolts 34 are installed. This kind of rail structure suits well in new installations where the doctor back is made for the assembly according to the invention. On the hand, an old doctor back may be machined if the assembly is rebuilt. - As shown in
Figure 3c , therail structure 14 consists of severalconsecutive segments 41 with interlocking design therebetween. Segments with one length may be manufactured and then install segments consecutively as many as needed. If necessary, one or more segments are shortened to adjust to the total length. The interlocking design ensures accurate alignment of the segments when assembled.Figure 3d shows one embodiment where on the left is asnick 42 and on the right is acorresponding notch 43. In the two-part rail structure this kind of design is not necessary, since the parts will be aligned by form guiding to the doctor back as explained above. Although, interlocking design may be utilized. - In principle, there are studs over the length of the doctor blade holder. Thus the doctor blade holder is firmly supported. Advantageously, at one end of the
rail structure 14 instead of thestuds 15 there is aslide bar 44 equipped with ahandle 45 outside the rail structure 14 (Figures 4a and 4b ) . First, theslide bar 44 is dimensioned in view of the rail structure. So extra clearances are avoided, and the support remains also at the end of the doctor blade holder. Second, thehandle 45 makes it possible to pull out the doctor blade holder by hand or using some pulling device. InFigures 4a and 4b , theslide bar 44 is mounted to thedoctor blade 12 holder with twomachine screws 20. Here, in addition, there areseveral holes 46 for attaching one kind of slide bar to any doctor blade holder model. Here thehandle 45 is a large hole in the end of the slide bar to allow for connecting heavy duty pull out hardware like shackle or like. - The slide bar has even more new features. The
slide bar 44 has severalconsecutive holes 47 for a lock downbolt 48. In practice, the lock down bolt prevents the doctor blade holder from moving in the cross-machine direction while in operation. The drilled and tapped holes are on the end of the slide bar before the handle. This construction allows for more cross machine adjustment of the doctor blade holder. Here there are fiveholes 47 with equal intervals of about 12 mm. So the position of the doctor blade holder can be adjusted precisely in cross-machine direction. For the lock down bolt, there is a threadedhole 49 at the end of therail structure 14, seeFigure 3c . Alternative, corresponding hole would be on the doctor back in the embodiments like inFigures 3b and4a . - As shown in
Figure 4b , between therail structure 14 and theslide bar 44 there is atransfer equipment 50. This transfer equipment is integrated into the slide bar and rail structure to facilitate initial sliding movement and fine tuning of the cross-machine position to insert the lock down bolt. Here, afork 51 is bolted to therail structure 14. Then there is a threadedblock 52 bolted to theslide bar 44. Between thefork 51 and the threadedblock 52 is anadjustment screw 53 equipped with alock nut 54. When uninstalling the doctor blade holder, the lock nut is first released and then theadjustment screw 53 is rotated to move the doctor blade holder out. The transfer equipment pulls out even if the studs are jammed to the rail structure. When the doctor blade holder moves a little bit, it will be easy to pull out using the handle. Also, the transfer equipment can be used to adjust the doctor blade holder during the installation. The adjustment screw as well the lock nut may be rotated with standard tools. Also, the transfer equipment can be installed on the other side of the rail structure. - The
doctor blade 11 as well as the doctor assembly has a length of several meters, from 1 to 11 meter extending in cross-machine direction. The doctor blade has a width from 5 to 20 centimeters extending in machine direction. - The stud according to the invention is simple but robust. With aid of other surprising features of the doctor blade holder, the installation and maintenance of the doctor blade holder assembly is easy and quick. At the same time, the doctor blade holder assembly is low in structure and is vibration-free. Also it is easy the maintain the doctor blade holder assembly, and it will suit for new installation and to retrofits.
Claims (15)
- Stud for a doctor blade holder in a fiber web machine, the stud (15) having a body (16) with a flange (17),
characterized in that the body (16) is a single piece having a form for a standard tool. - Stud according to claim 1, characterized in that the form includes two opposite flats (18) arranged in the flange (17) .
- Stud according to claim 1 or 2, characterized in that there is a rotating piece (21) arranged around the body (16) made of bronze.
- Stud according to any of claims 1 - 3, characterized in that the body (16) has a circumferential shoulder (22) at an end (23) opposite to the flange (17).
- Doctor blade holder assembly for a fiber web machine, the assembly has a blade holder (12) arranged movable to a rail structure (14) with a plurality of consecutive studs (15) having a body (16) with a flange (17), characterized in that the majority of the studs are studs according to any of claims 1 - 4.
- Assembly according to claim 5, characterized in that the body (16) has outer dimensions according to the rail structure (14).
- Assembly according to claim 5 or 6, characterized in that the rail structure (14) is of solid metal namely bronze or stainless steel.
- Assembly according to any of claims 5 - 7, characterized in that the rail structure (14) has an entry area (32) with funnel shape.
- Assembly according to any of claims 5 - 8, characterized in that the rail structure (14) has counter bored slots (33) for back bolts (34).
- Assembly according to any of claims 5 - 9, characterized in that the rail structure (14) includes two rail parts (35, 36) arranged apart from each other.
- Assembly according to claim 10, characterized in that one or both of the parts (35, 36) is installed on a doctor back (13) by form guiding.
- Assembly according to any of claims 5 - 11, characterized in that the rail structure (14) consists of several consecutive segments (41) with interlocking design therebetween.
- Assembly according to any of claims 5 - 12, characterized in that at one end of the rail structure (14) instead of the studs (15) there is a slide bar (44) equipped with a handle (45) outside the rail structure (14).
- Assembly according to claim 13, characterized in that the slide bar (44) has several consecutive holes (47) for a lock down bolt (48).
- Assembly according to claim 13 or 14, characterized in that between the rail structure (14) and the slide bar (44) there is a transfer equipment (50).
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US202263409602P | 2022-09-23 | 2022-09-23 | |
FI20225910A FI20225910A1 (en) | 2022-09-23 | 2022-10-07 | Stud for a doctor blade holder in a fiber web machine and doctor blade holder assembly for a fiber web machine |
Publications (2)
Publication Number | Publication Date |
---|---|
EP4343060A2 true EP4343060A2 (en) | 2024-03-27 |
EP4343060A3 EP4343060A3 (en) | 2024-05-01 |
Family
ID=88147093
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP23198694.4A Pending EP4343060A3 (en) | 2022-09-23 | 2023-09-21 | Stud for a doctor blade holder in a fiber web machine and doctor blade holder assembly for a fiber web machine |
Country Status (1)
Country | Link |
---|---|
EP (1) | EP4343060A3 (en) |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20020153114A1 (en) | 2001-04-24 | 2002-10-24 | Brauns Allen J. | Removable doctor blade holder |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5980692A (en) * | 1997-12-22 | 1999-11-09 | Thermo Web Systems, Inc. | Removable doctor blade holder |
EP3399099A1 (en) * | 2017-05-03 | 2018-11-07 | Oradoc S.r.l. | Rigid and flexible doctor blade holder and system comprising a cylinder and a doctor blade holder |
-
2023
- 2023-09-21 EP EP23198694.4A patent/EP4343060A3/en active Pending
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20020153114A1 (en) | 2001-04-24 | 2002-10-24 | Brauns Allen J. | Removable doctor blade holder |
Also Published As
Publication number | Publication date |
---|---|
EP4343060A3 (en) | 2024-05-01 |
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