EP4667653A1

EP4667653A1 - Siphon assembly for a dryer cylinder of a fiber web machine, method for balancing a dryer cylinder of a fiber web machine and a dryer cylinder of a fiber web machine

Info

Publication number: EP4667653A1
Application number: EP25176536.8A
Authority: EP
Inventors: Simo PAANANEN
Original assignee: Valmet Technologies Oy
Current assignee: Valmet Technologies Oy
Priority date: 2024-06-20
Filing date: 2025-05-15
Publication date: 2025-12-24
Also published as: CN121183614A

Abstract

The invention relates to a siphon assembly for a dryer cylinder of a fiber web machine. The siphon assembly (13) has a steam pipe (14) and a condensate pipe (15) arranged coaxially to be installed to a steam connection (16). The siphon assembly (13) is balanced before installation. The invention relates also relates to a method for balancing a dryer cylinder of a fiber web machine and a dryer cylinder of a fiber web machine.

Description

The invention relates to siphon assembly for a dryer cylinder of a fiber web machine, which siphon assembly has a steam pipe and a condensate pipe arranged coaxially to be installed to a steam connection. The invention relates also to a method for balancing a dryer cylinder of a fiber web machine and a dryer cylinder of a fiber web machine.
Each fiber web machine has some kind of dryer section for drying the fiber web. One way for drying is to use several consecutive dryer cylinders arranged in two or more overlapping rows. The dryer cylinder is heated with steam which is led into the hollow dryer cylinder. Inside the dryer cylinder steam condensates turning into water, giving up its latent heat. The latent heat is the motive heat source for drying the fiber web. Water must be removed to ensure effective heat flow. For removal, a siphon assembly is used. The siphon assembly has a steam pipe and a condensate pipe arranged coaxially. The steam pipe leads steam inside the dryer cylinder while the condensate pipe leads condensate out of the dryer cylinder. The siphon assembly is installed in a journal bore and supported to a steam connection. The journal will rotate with the dryer cylinder, but the steam connection together with the siphon assembly is stationary.
Stationary siphon assemblies stay still while the drying cylinder rotates. Then the condensate pipe is like a cantilever supported only from the steam connection. With small diameter dryer cylinders, the journal bore is small and the condensate pipe this thin. In practice, it is hard to reach efficient condensate removal. Also, the siphon assembly is hard to assemble due the small size of the shell. This makes also hard to balance the dryer cylinder. In addition, this structure has 1000 meters per minute as the highest speed performed. EP2017517 discloses a siphon assembly for small cylinders. The shown siphon assembly has a hinged joint that enables siphon assembly through the journal. Such a structure has limited strength which limits the dryer cylinder top speed to 1000 meters per minute.
It is an object of the invention to provide for a dryer compact cylinder of a fiber web machine a new type of siphon assembly, which is suitable for much higher speed than before. The characteristic features of the siphon assembly according to this invention are stated in the accompanying claim 1. Another object of the invention is to provide for balancing a dryer cylinder of a fiber web machine a novel method which is more accurate. The characteristic features of the method according to this invention are stated in the accompanying claim 4. Still another object of the invention is to provide a novel drying cylinder which has improved condensate removal properties also in high speeds and which is easy to assemble. The characteristic features of the dryer cylinder according to this invention are stated in the accompanying claim 12. The siphon assembly according to the invention is suitable for use with various drying cylinders, especially with small diameter dryer cylinders. The method enables an easy and precise balancing of the dryer cylinder with simple steps. The dryer cylinder has a great efficiency in condense removal. In addition, the siphon assembly works safely also in high speeds.
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 the tending-side end of a dryer cylinder according to the invention,
Figure 2: shows the tending-side end of a dryer cylinder according to the invention in cross section,
Figure 3: shows the siphon assembly according to the invention before installation,
Figure 4: shows the dryer cylinder according to the invention during balancing.

Figure 1 shows a tending-side end of a dryer cylinder 10 of a fiber web machine. If necessary, condensate removal may be at both end of the dryer cylinder (not shown). The dryer cylinder 10 has a shell 11 having a journal 12 mounted to the shell 11 or a dryer head 29. The journal is also called as a flanged shaft, since the shaft is a short stub including a flange. The dryer cylinder 10 further has a siphon assembly 13 including a steam pipe 14 and a condensate pipe 15. The steam pipe 14 and the condensate pipe 15 are arranged coaxially and installed to a steam connection 16. In the shown embodiment there is also an insulation sleeve 17 through which the siphon assembly goes. However the insulation sleeve 17 is optional. The steam connection 16 is shown in Figures 1 and 2. Steam is led from below to the steam connection 16 and thereby through openings 18 into the steam pipe 14 and finally into the dryer cylinder 10. The condensate pipe 15 runs inside the steam pipe 14 and reaches to the inner surface of the shell 11 after an elbow 19 including a siphon 20. The overpressure inside the dryer cylinder pushes condensate to the condensate pipe and out of the dryer cylinder.
Basically, the siphon assembly has a pipe inside the dryer cylinder through which condensate is removed from the dryer cylinder. The pipe extends down close to the dryer shell to keep the condensate film as thin as possible. The siphon assembly 13 is installed in a journal bore 21 going through a journal 12 supporting the shell 11. The journal 12 is fixed to the shell 11 with bolts 22 and supported with bearings 23. In practice, the journal with the shell rotates while the siphon assembly and the steam connection are stationary. In other words, the siphon assembly 13 is mounted stationary. In addition, inside the journal bore 21 there is the insulation sleeve 17. The journal of the dryer cylinder is thereby insulated from steam inside the dryer cylinder by the internal insulating sleeve. The insulating sleeve is a flanged tube that extends through the journal bore. The flanged end 31 of the sleeve is usually bolted to the inside surface of the dryer head and sealed by a gasket. The opposite end of the insulating sleeve is usually sealed by O-rings in a journal adaptor flange. The insulating sleeve creates an insulating air gap in the annular space between the sleeve and the journal bore. This insulating air gap helps to protect the inner race of the bearings and maintain oil viscosity to provide long bearing life.
Figure 3 shows the siphon assembly 13 before installing. According to the invention the siphon assembly 13 is balanced before installation to the dryer cylinder 10. If the insulation sleeve is used, siphon assembly 13 is balanced with insulation sleeve. Then, all three parts, i.e., the insulation sleeve 17, the steam pipe 14 and the condensate pipe 15 are fixed coaxially together. In this way, the siphon assembly can be easily and precisely balanced. Here, at the outer end is a flange 24 securing the parts together. Before installing the steam connection, the flange is removed (Figure 2). At the inner end there is a lock ring 25, which is removed after balancing and installation. After balancing, the dryer cylinder 10 is balanced according to the method explained in detail later. The dryer cylinder in easily and precisely balanced. Thus the dryer cylinder can have diameter less than 1200 mm, but still rotating even 2000 meters per minute.
As explained earlier, the siphon assembly is for a dryer cylinder of a fiber web machine. The siphon assembly 13 has the steam pipe 14 and the condensate pipe 15 arranged coaxially to be installed to the steam connection 16 through the insulation sleeve 17. According to the invention, the siphon assembly 13 is balanced before installation (Figure 3). In addition, the steam pipe 14 has a balancing surface 26. During balancing, the steam pipe is centered with the lock ring 25. At the other end, the flange 24 fixes and centers the parts. As well the balancing surface 26, the flange 24 creates another balancing surface. Balancing is explained later in more detail. As said, the siphon assembly 13 is fixed to the insulation sleeve 17 at both ends during balancing, but advantageously also during transporting. Thus the balanced siphon assembly keeps it accuracy for a long time even after transporting.
The method according to the invention is for balancing a dryer cylinder of a fiber web machine. The present dryer cylinders are designed for a modern high speed fiber web machine, and they spin at high speed. So it is vital to balance the dryer cylinders to avoid vibrations, for example. In the method the dryer cylinder 10 is equipped with the siphon assembly 13. The siphon assembly has the steam pipe 14 and the condensate pipe 15 arranged coaxially and installed to the steam connection 16 through the insulation sleeve 17, as explained above. Finally in the method, the dryer cylinder 10 is balanced. Now the balancing is made in steps since the siphon assembly 13 is first balanced with the insulation sleeve 17 before installation to the dryer cylinder 10. After this the dryer cylinder in balanced with the siphon assembly.
Also the siphon assembly itself is balanced also in steps. First, the siphon assembly 13 is balanced programmatically. This is done by any suitable design software. In other words, all three parts are designed together so that combination is in balance with respect to the center axis. Second, using two balancing surfaces, the siphon assembly is then balanced statically. The balancing surface 26 and the flange 24 are circular with center at the center axis. Figure 3 shows two sensitive rotating supports 27 on which the siphon assembly lays. Then the siphon assembly is turned to different angles. Opposite to the siphon 20 there is an adjustable counterweight 28. Mostly by adjusting the position of the counterweight, the siphon assembly is balance. When the siphon assembly is balanced correctly, it will stay in any angle without rotating. The rotating support 27 can be situated also at the flanged end 31.
Figure 4 shows the dryer cylinder during balancing. The dryer cylinder 10 has a shell 11 having a journal 12 mounted to the shell 11 via a dryer head 29. As earlier stated, the siphon assembly 13 is balanced before mounting the journal 12. More precisely, the balanced siphon assembly 13 is placed inside the shell 11, then the journal 12 is fixed to the dryer head 29 or shell 11 while pulling the siphon assembly 13 through the journal 12. This is preassembling before balancing the dryer cylinder. After installing the journal 12 and the siphon assembly 13, the dryer cylinder 10 is balanced without the steam connection. When assembling the dryer cylinder 10 at the site, the journal 12 and the balanced siphon assembly 13 are installed and the siphon assembly 13 is pulled axially to an installation position, and the siphon 20 is radial adjusted via a handhole 30 including to the dryer head 29. However, the dryer is compact without any manhole. In Figure 4 the siphon assembly 13 is in a balancing position when the elbow 19 is more inside than when in use and the siphon assembly is locked with a locking ring 25. Also the siphon 20 is distant from the inner surface of the shell 11. Then like in Figure 2, the siphon assembly 13 is pulled out and the elbow 19 is closed to the journal 12. Simultaneously, the condensate pipe 15 comes out and the steam connection 16 is installed. Then the siphon 20 is extended near the inner surface of the shell 11. In spite the balancing surface, there is clearance enough between the siphon assembly and the insulation sleeve. In addition, the whole dryer cylinder is balanced precisely. In practice, the dryer cylinder 10 with the siphon assembly 13 is balanced for 1200 - 2000, advantageously 1300 - 1800 meters per minute. Then it can be ensured high speed during the production, even with small size dryer cylinders. After balancing the dryer cylinder 10, the siphon assembly 13 is released by removing the lockring 25. Then the siphon assembly 13 is locked outside of the dryer cylinder 10 by replacing the balancing flange by another flange for transporting.
According to the method, the siphon assembly is balanced before mounted to the dryer cylinder. In addition, the siphon assembly is balanced with the insulating sleeve, if any and then the dryer cylinder is balanced together with the siphon assembly. In the static balancing, balancing weights are added to siphon assembly until the it remains static in any orientation or angle. During balancing, turning by hand is ensured that the siphon assembly stays balanced in place no matter what position without turning due to the gravity. Even the siphon assembly weights tens of kilograms, the allowed unbalance is only few tens of grams. If the dryer cylinder would be balanced for the maximum speed of 1100 meter per minute, the allowed unbalance would be few hundreds of grams. Instead, according to the method, the dryer cylinder is for the maximum speed of 2000 meter per minute. Then the allowed unbalance would be about one hundred grams. However, when using the method according to the invention, i.e., balancing the siphon assembly first independently and with the whole assembly, the allowed unbalance will be enough, and it can be ensured the top speed up to 2000 meter per minute with well-functioning condense removal.

Claims

Siphon assembly for a dryer cylinder of a fiber web machine, which siphon assembly (13) has a steam pipe (14) and a condensate pipe (15) arranged coaxially to be installed to a steam connection (16), characterized in that the siphon assembly (13) is balanced before installation.
Siphon assembly according to claim 1, characterized in that the siphon assembly (13) is balanced with an insulation sleeve (17), and siphon assembly (13) is fixed to the insulation sleeve (17) at both ends during balancing.
Siphon assembly according to claim 2, characterized in that the siphon assembly (13) is fixed to the insulation sleeve (17) at both ends during transporting.
Method for balancing a dryer cylinder of a fiber web machine, in which method the dryer cylinder (10) is equipped with a siphon assembly (13) which has a steam pipe (14) and a condensate pipe (15) arranged coaxially and installed to a steam connection (16), and the dryer cylinder (10) is balanced, characterized in that the siphon assembly (13) is balanced before installation to the dryer cylinder (10).
Method according to claim 4, characterized in that the siphon assembly (13) is balanced first programmatically, then statically.
Method according to claim 4 or 5, characterized in that the dryer cylinder (10) has a shell (11) having a journal (12) mounted to the shell (11) via a dryer head (29), and the siphon assembly (13) is balanced before mounting the journal (12).
Method according to claim 6, characterized in that the balanced siphon assembly (13) is placed inside the shell (11), then the journal (12) is fixed to the dryer head (29) or shell (11) while pulling the siphon assembly (13) through the journal (12).
Method according to claim 7, characterized in that after installing the journal (12) and the siphon assembly (13), the dryer cylinder (10) is balanced without the steam connection (16).
Method according to claim 8, characterized in that after balancing the dryer cylinder (10), the siphon assembly (13) is released and then locked outside of the dryer cylinder (10).
Method according to any of claim 4 - 8, characterized in that when assembling the dryer cylinder (10), the journal (12) and the balanced siphon assembly (13) are installed and the siphon assembly (13) is pulled axially to an installation position, and a siphon (20) including to the siphon assembly is radial adjusted via a hand hole (30) including to the dryer head (29).
Method according to any of claim 4 - 9, characterized the dryer cylinder (10) with the siphon assembly (13) is balanced for 1200 - 2000, advantageously 1300 - 1800 meters per minute.
Dryer cylinder of a fiber web machine, the dryer cylinder (10) has a shell (11) having a journal (12) mounted to the shell (11) or a dryer head (29), and the dryer cylinder (10) further has a siphon assembly (13) including a steam pipe (14) and a condensate pipe (15) arranged coaxially and installed to a steam connection (16), characterized in that the siphon assembly (13) is balanced before installation to the dryer cylinder (10).
Dryer cylinder according to claim 12, characterized in that the dryer cylinder (10) has diameter less than 1200 mm.
Dryer cylinder according to claim 12 or 13, characterized in that dryer cylinder (10) is balanced according to the method of any of claims 4 - 11.
Dryer cylinder according to any of claims 12 - 14, characterized in that the siphon assembly (13) is mounted stationary.