SE2050409A1 - Yankee cylinder cleaning assembly for collecting waste material from a yankee cylinder in tissue paper production - Google Patents

Abstract

The present invention relates to a Yankee cylinder cleaning assembly (10) for collecting waste material from a Yankee cylinder (30) in tissue paper production, the cleaning assembly comprising a catch pan (11) extending from a first end (A) to a second end (B), the catch pan (11) having an elongated body (12) with an open upper side (13) for receiving waste material into the catch pan (11) and a lower side (14) for gathering the waste material, wherein the catch pan (11) is configured to be mounted in connection with a cleaning blade (20) at a Yankee cylinder so that waste material being scraped from the Yankee cylinder by the cleaning blade is received by the cleaning assembly (10).

Description

YANKEE CYLINDER CLEANING ASSEMBLY FOR COLLECTING WASTEMATERIAL FROM A YANKEE CYLINDER IN TISSUE PAPER PRODUCTION TECHNICAL FIELD The present invention discloses a Yankee cylinder cleaning assembly forcollecting waste material from a Yankee cylinder in tissue paper production,wherein the cleaning assembly comprises a catch pan eXtending from a firstend to a second end, the catch pan having an elongated body with an openupper side for receiving waste material into the catch pan and a lower side for gathering the waste material.BACKGROUND In tissue paper production, a Yankee cylinder is used as a final drying stepin which a paper web is transferred from a carrying fabric such as a felt,belt, wire, or synthetic fabric to the surface of the Yankee cylinder for dryingbefore being removed by a creping blade. In order for the paper web toadhere to the surface, a coating with an adhesive is applied to the Yankeecylinder and after the paper has been removed by the creping blade, thecoating, residual fiber and material from the papermaking process(collectively known as waste material) is generally scraped from the surface by a doctor blade.

In recent years, the health and safety issues have gained importance so thatmanual access to the production line is now limited to prevent injury tohuman operators working in the area. This creates problems with cleaningthe area since machinery must be stopped before persons are allowed toenter the area. In order to remove the waste material scraped from theYankee cylinder, the floor around the machinery is regularly hosed downwith water after production is halted. This in turn results in the wastematerial ending up in waste water from the production so that methods ofcleaning the waste water from chemicals in the coating are necessary before re-using the water.

Having to interrupt production in order to clean the area is generallyundesired and costly, but there is also a problem during operation When theWaste material scraped from the Yankee cylinder may form a slippery surfaceon floors around the machinery, increasing the risk of accidents and injury for human operators.

There is therefore a need for improvement in the field of tissue production to alleviate these problems.SUMMARY The object of the present invention is to eliminate or at least to minimize theproblems discussed above. This is achieved by a Yankee cylinder cleaningassembly for collecting Waste material from a Yankee cylinder in tissue paper production according to the appended independent claim.

The Yankee cylinder cleaning assembly comprises a catch pan extendingfrom a first end to a second end, the catch pan having an elongated bodyWith an open upper side for receiving Waste material into the catch pan anda lower side for gathering the Waste material, Wherein the catch pan isconf1gured to be mounted in connection With a cleaning blade at a Yankeecylinder so that Waste material being scraped from the Yankee cylinder bythe cleaning blade is received by the cleaning assembly. This significantlydecreases the risk of contamination to cleaning fluids used to clean floorsand other surfaces at or near machinery and it also decreases the risk ofinjury to human operators Walking on floors Where Waste material from theYankee cylinder Would otherwise have been accumulating. It is also anadvantage from a cost standpoint since cleaning intervals can be longer so that periods of production standstill can be minimized.

Suitably, the Yankee cylinder cleaning assembly further comprises at leastone fluid inlet and at least one outlet in the catch pan for introducing acleaning fluid and removing Waste material and the cleaning fluid. Thereby,Waste material is removed in an efficient Way, preventing the catch pan from getting full and loWering the need for maintenance at the catch pan.

At least one of the fluid inlet and the outlet may further be arranged at oneof the first end and second end. This allows for efficient flushing of the catchpan so that waste material can be guided towards the outlet for removal from the pan.

Suitably, at least one inner surface of the catch pan comprises a non-stickcoating. This further increases the efficiency in gathering waste material at the lower side or transporting it towards the outlet.

The cleaning assembly may further comprise at least one mounting devicefor mounting the cleaning assembly in connection with a Yankee cylinder.Thereby, the catch pan can be mounted in a position at the Yankee cylinder so that waste material is eff1ciently and conveniently captured.

Suitably, a cleaning blade is also provided for scraping the surface of aYankee cylinder, wherein the catch pan is arranged in connection with thecleaning blade so that waste material scraped from the Yankee cylinder fallsdown into the catch pan. Thereby, the surface of the Yankee cylinder is eff1ciently cleaned and waste material is gathered as desired.

The cleaning assembly may further be conf1gured for continuous wasteremoval from the cleaning assembly by the at least one fluid inlet and atleast one outlet being conf1gured for continuous supply of cleaning fluid andcontinuous outlet of waste material and cleaning fluid. Thereby,accumulation of larger quantities of waste material is prevented, thus also lowering the risk of plugs forming in the outlet.

Also, at least two fluid inlets may suitably be arranged in the catch pan,wherein preferably one fluid inlet is arranged at the first end and anotherfluid inlet is arranged at the second end. This also allows for an efficientflushing of the catch pan so that waste material is removed in a suitable way.

Suitably, the cleaning assembly comprises a plurality of fluid inletsdistributed along the catch pan from the first end to the second end,preferably arranged along the upper side. Thereby, cleaning fluid can besupplied in multiple locations along the upper side to create a flow of fluidalong an inner surface of the catch pan in order to flush waste material towards the lower side of the catch pan.

The plurality of fluid inlets are suitably provided along at least one conduitthat extends along the upper side. Thereby, the fluid inlets can bedistributed along the upper side and the number of components can be keptlow, keeping the construction and function of the cleaning assembly simple and cost efficient.

Suitably, the plurality of fluid inlets are provided along the upper side on afirst side and on a second side. Thereby, both sides can be flushed withcleaning fluid so that waste material is transported into the catch pan in anefficient way.

Many additional benefits and advantages of the present invention will bereadily understood by the skilled person in view of the detailed description below.DRAWINGS The invention will now be described in more detail with reference to the appended drawings, wherein Fig. 1 discloses a perspective view of a cleaning assembly according tothe invention; andFig. 2 discloses schematically the cleaning assembly of Fig. 1 mounted in connection with a Yankee cylinder.DETAILED DESCRIPTION Fig. 1 discloses a Yankee cylinder cleaning assembly 10 according to a preferred embodiment of the present invention, with a catch pan 11 having an elongated body 12 that extends from a first end A to a second end B. Thecatch pan 11 has an upper side 13 that is open so that waste material canenter the catch pan 11, and a lower side 14 that is closed so that the wastematerial can be gathered. At the first end A there may be a fluid inlet 15 forintroducing a cleaning fluid such as water into the body 12 of the catch pan11. Such a fluid inlet 15 may also or alternatively be arranged at the secondend B. Optionally, a fluid inlet may also or alternatively be arranged alongthe body 12 in a way suitable for flushing the waste material from the catch pan 11.

In one advantageous embodiment, a plurality of fluid inlets 15 are providedalong the upper side 13 of the catch pan 11 on both a first side C and asecond side D of the catch pan 11. The fluid inlets 15 may be arranged asopenings or nozzles in a conduit 18 that extends along the upper side 13from the first end A to the second end B or in opposite direction. Byproviding a plurality of fluid inlets 15 and arranging them along the upperside 13 a flow of cleaning fluid along an inner surface 17 of the catch pan 11can be achieved so that waste material W that falls on the inner surface 17 is flushed towards the lower side 14 of the catch pan 11.

The cleaning assembly 10 may also comprise a mounting device 60 that inthe preferred embodiment is arranged at the first end A and the second endB so that the cleaning assembly 10 can be mounted in connection with acleaning blade 20 (see Fig. 2) in order to catch waste material falling from aYankee cylinder 30. Furthermore, a mechanical screen 50 may be providedto guide the waste material into the catch pan 11. The cleaning blade 20 may also be referred to as a doctor blade or a scraper.

An inner surface 17 of the catch pan 11 may be coated with a non-stickmaterial that creates a surface with low friction so that any waste materialthat lands on the surface 17 continues sliding along the surface 17 towardsthe lower side 14 and gather at a bottom of the catch pan 11. In someembodiments, the catch pan 11 may be coated with a non-stick material onall internal surfaces and fluid inlets 15 and outlet 16 may also be coated with non-stick material. This is advantageous in allowing for efficient transport of any waste material and preventing build-up of waste materialanywhere in the CatCh pan 11. It also faCilitates Cleaning and maintenance ofthe Cleaning assembly 10. Suitable non-stiCk materials inCludepolytetrafluoroethylene (PTFE) (CommerCially known by the brand nameTeflon) but many other materials are also suitable as long as they Can be used to Create a low friCtion surfaCe.

Fig. 2 disCloses the Cleaning assembly 10 mounted in ConneCtion with aCleaning blade 20 at a Yankee Cylinder 30. That the Cleaning assembly 10 ismounted in ConneCtion with the Cleaning blade 20 means that any wastematerial that is sCraped from a surfaCe of the Yankee Cylinder 30 by theCleaning blade 20 Can be Captured by the Cleaning assembly 10 by fallinginto the CatCh pan 11.

Also mounted at the Yankee Cylinder 30 is a Creping blade 40 that removestissue paper from the Yankee Cylinder 30, and the Cleaning assembly 10 is inthis preferred embodiment mounted below the Cleaning blade 20 and a partof the Yankee Cylinder 30 that is between the Creping blade 40 and theCleaning blade 20. Also provided is a meChaniCal sCreen 50 that serves toguide waste material into the CatCh pan 11 and ensure that waste material isnot allowed to spread over a larger area where the CatCh pan 11 is not able to reCeive it.

Fig. 2 disCloses that walls at the upper side 13 of the CatCh pan are inClinedso that the waste material W is able to slide in a direCtion marked by arrowsalong a surfaCe 17 of the inClined walls and fall down towards the lower side14 and gather at the bottom. Suitably, non-stiCk walls are provided along anentirety of the inClined walls to prevent waste material W from getting stuCkthere. An arrow at the lower side 14 indiCate an eXhaust flow direCtion fromthe CatCh pan 11. However, in some embodiment the outlet 16 Can bearranged so that an eXhaust flow is direCted horizontally or at an angle to a horizontal direCtion instead.

The outlet 16 may advantageously be ConneCted to an eXhaust air system that inCludes duCting, water separator and Centrifugal air fan.

In one embodiment, inlets 15 are provided at both ends A, B of the catch pan11 and the outlet 16 is provided in a middle portion between the ends A, Band directed downwards so an eXhaust flow may exit the catch pan 11 in adownwards direction. In another embodiment, an inlet 15 may be providedat one end and the outlet 16 at the other end. In some embodiments, theinlet(s) 15 may be provided at the lower side 14 of the catch pan 11, but inanother embodiment inlet(s) 15 may also or alternatively be provided at theupper side 13 and flow across the inclined walls to flush the waste materialW into the catch pan 11. In such embodiments as also mentioned above, itmay be advantageous to provide a plurality of inlets 15 distributed along theupper side 13 of the catch pan 11 for a part of a distance from the first end Ato the second end B, or alternatively along the entire distance between theends A, B. It may also be advantageous to provide the inlets distributedalong the upper side 13 on both sides of the catch pan 11, i.e. at both theleft-hand side or first side C and the right-hand side or second side D of the catch pan 11 as seen in Fig. 2.

Use of the cleaning assembly will now briefly be described with reference to the Figures.

Tissue paper is produced in a manner already well known within the art,and as one of the final steps a paper web is dried by adhering to the surfaceof the Yankee cylinder 30. The paper is then removed by the creping blade40 and the Yankee cylinder 30 continues its rotation in a counter-clockwisedirection as seen in Fig. 2. Thus, after the surface has been scraped by thecreping blade 40, the cleaning blade 20 is arranged to also scrape thesurface of the Yankee cylinder 30 but with the purpose of removing wastesuch as adhesive, other coating substances, dust, leftover particles from thepaper web, etc. As the surface of the Yankee cylinder 30 rotates to pass thecleaning blade 20, any such waste material is removed so that the surface isclean and ready to be used again. The waste material W removed by thecleaning blade 20 falls from the cleaning blade 20 and enters the catch pan 11, possibly after being guided towards the catch pan 11 by the screen 50 or by holders and structures arranged with or at the Cleaning blade 20 and/ or the creping blade 40.

In the catch pan 11, the waste material W proceeds from the upper side 13to the lower side 14. In one basic embodiment, the waste material W isgathered at the lower side 14 and kept there until being emptied out inconnection with maintenance of the cleaning assembly 10. In order to ensurethat the waste material W stays firmly inside the catch pan 11, a fluid suchas water may be added by spraying or flushing into the catch pan 1 1 so that the waste material W is contained in the fluid.

In the preferred embodiment, a continuous supply of cleaning fluid isprovided so that at least the lower side 14 but possibly also the upper side13 of the catch pan 11 are continuously flushed and the waste material W istransported towards the outlet 16 and removed from the catch pan 11. Thus,in that preferred embodiment the need for maintenance of the cleaningassembly 11 is very low since waste material W is removed before the catchpan 11 becomes full. Due to the continuous supply of cleaning fluid, theoutlet is prevented from clogging since plugs of waste material W is unlikely to form when it is not gathered in larger quantities inside the catch pan 11.

It is to be noted that features from the various embodiments describedherein may freely be combined, unless it is explicitly stated that such a combination would be unsuitable.

Claims (1)

1. Yankee cylinder cleaning assembly for collecting Waste material from aYankee cylinder in tissue paper production, the cleaning assemblycomprising a catch pan (11) eXtending from a first end (A) to a secondend (B), the catch pan (11) having an elongated body (12) With an openupper side (13) for receiving Waste material into the catch pan (11) and a lower side (14) for gathering the Waste material, Wherein the catch pan (11) is configured to be mounted in connectionWith a cleaning blade (20) at a Yankee cylinder (30) so that Wastematerial being scraped from the Yankee cylinder (30) by the cleaning blade (20) is received by the cleaning assembly (10). . Cleaning assembly according to claim 1, further comprising at least one fluid inlet (15) and at least one outlet (16) in the catch pan (11) forintroducing a cleaning fluid and removing Waste material and the cleaning fluid. . Cleaning assembly according to claim 2, Wherein at least one of the fluid inlet (15) and the outlet (16) is arranged at one of the first end (A) and second end (B). Cleaning assembly according to any of claims 1-3, Wherein further atleast one inner surface (17) of the catch pan (11) comprises a non- stick coating. . Cleaning assembly according to any of claims 1-4, further comprising at least one mounting device (60) for mounting the cleaning assembly (10) in connection With a Yankee cylinder (30). Cleaning assembly according to any of claims 1-5, further comprisinga cleaning blade (20) for scraping a surface of a Yankee cylinder (30), Wherein the catch pan (11) is arranged in connection With the cleaning 9 blade (20) so that Waste material scraped from the Yankee cylinder (30) falls down into the catch pan (11). . Cleaning assembly according to any of claims 2-6, further being configured for continuous Waste removal from the cleaning assemblyby the at least one fluid inlet (15) and at least one outlet (16) beingconfigured for continuous supply of cleaning fluid and continuous outlet of Waste material and cleaning fluid. . Cleaning assembly according to any of claims 2-7, further comprising at least two fluid inlets (15) that are arranged in the catch pan (11),Wherein preferably one fluid inlet (15) is arranged at the first end (A) and another fluid inlet (15) is arranged at the second end (B). . Cleaning assembly according to any previous claim, further comprising a plurality of fluid inlets (15) distributed along the catchpan (11) from the first end (A) to the second end (B), preferablyarranged along the upper side (13). Cleaning assembly according to claim 9, Wherein the plurality offluid inlets (15) are provided along at least one conduit (18) that extends along the upper side (13). Cleaning assembly according to claim 9 or 10, Wherein theplurality of fluid inlets (15) are provided along the upper side (13) on a first side (C) and on a second side (D).