Some thoughts onYankeeSome thoughts onYankee
Paper Machine Felt LifePaper Machine Felt Life
Concept:
D K Singhal
deveshksi...
The PresentationThe Presentation
The presentation is based on my personal
experiences and knowledge acquired over
a period...
Felt Life: What it should be?Felt Life: What it should be?
Unfortunately, we have to just depend on
previous felt life tre...
Felt Life PredictionFelt Life Prediction
It is not difficult to estimate the felt life
on the basis of different parameter...
What Does the Press Do?What Does the Press Do?
Simple.The purpose of a press section is
to squeeze the excess water from t...
Press Squeezed WaterPress Squeezed Water
However, the squeezed water is not
clean.There are a lot of fines in it. These
fi...
Felt ConditioningFelt Conditioning
The objective of felt conditioning is to
remove all trapped fiber fines from the
felt.
...
Felt Wear on Suction BoxesFelt Wear on Suction Boxes
When a felt passes over the suction
(uhle) box, due to wear, some of ...
Yankee MachinesYankee Machines
Yankee machines have two different felt
configurations-
Pick Up Felt (no press)
Pick Up Fel...
What Makes Top Felt ImportantWhat Makes Top Felt Important
Being yankee cylinder the only drying
cylinder, proper pressing...
Back to the Wire PartBack to the Wire Part
Stock from the headbox lands on the
wire part. Most long fibers remain on the
w...
Fines DistributionFines Distribution
As obvious, most fines from the bottom
layer of paper web drain out while the
fines i...
Yankee FeltYankee Felt
Whatever be the machine configuration-
with press section or just yankee touch
roll after the wire ...
Yankee FeltYankee Felt
If these fines are not removed effectively,
the felt gets choked up too early.
If we are able to im...
Felt Choked with FinesFelt Choked with Fines
To evaluate the quantity of fines in the
felt, an old used felt just prior to...
Felt Choked with FinesFelt Choked with Fines
The new felt was of 1286 gsm (design
1300gsm), and in spite of some felt yarn...
FPRFPR
So, FPR plays a critical role in getter
better yankee felt life.
Other aspect is good felt conditioning.
Felt condi...
Felt ConditioningFelt Conditioning
Periodic use of flooding shower from the
inside of felt circuit may help a lot.
Additio...
Kerosene Based CleaningKerosene Based Cleaning
To recall, the procedure is as under-
◦ Stop all showers, reduce load to mi...
Felt Cleaning ChemicalsFelt Cleaning Chemicals
Alternate to kerosene, ask your chemical
supplier to suggest a good felt cl...
Press LoadingPress Loading
Yankee machines generally have limited
press nips.
There could be a solid double felted
press, ...
Touch Roll LoadingTouch Roll Loading
However, the critical part is the nip
between yankee touch roll and hot
yankee cylind...
Touch Roll LoadingTouch Roll Loading
Furthermore, in longer nip with low basis
weight papers, a lot of heat is also
transf...
Excess Nip LoadingExcess Nip Loading
Excess nip loading also results in more
felt compression each time the felt passes
th...
Optimizing Nip LoadingOptimizing Nip Loading
Many papermakers tend to use as high nip
loading as possible in order to get ...
SummarySummary
In a nut shell, three main parameters need
attention if yankee felt life is too low-
1. FPR1. FPR
2. Nip Lo...
ThankYou.ThankYou.ThankYou.ThankYou.
27
Some thoughts onYankee Paper Machine
Felt Life, June 2014
About the Author:
Born in 1968, D K Singhal is B.E., M.E. (Pulp & Paper, 1993) from Deptt. of Paper
Technology, University...
Upcoming SlideShare
Loading in...5
×

Some thoughts on yankee paper machine felt life

1,381
-1

Published on

Paper machine Clothing, felt, Yankee, MG, Touch Roll, Felt Cleaning

Published in: Technology, Business, Lifestyle

Some thoughts on yankee paper machine felt life

  1. 1. Some thoughts onYankeeSome thoughts onYankee Paper Machine Felt LifePaper Machine Felt Life Concept: D K Singhal deveshksinghal@gmail.com
  2. 2. The PresentationThe Presentation The presentation is based on my personal experiences and knowledge acquired over a period of time. This presentation just aims to share myThis presentation just aims to share my views, and readers are advised to consult their machinery clothing manufacturers, machine designers and experts before making any changes in their machine operating parameters. 2 Some thoughts onYankee Paper Machine Felt Life, June 2014
  3. 3. Felt Life: What it should be?Felt Life: What it should be? Unfortunately, we have to just depend on previous felt life trend, and predicting the life of the felt is just a good guess. It is often difficult to estimate the felt lifeIt is often difficult to estimate the felt life as a function of machine speed, quality and gsm, number of conditioning boxes, applied vacuum, type and operating pressure in press section etc. 3 Some thoughts onYankee Paper Machine Felt Life, June 2014
  4. 4. Felt Life PredictionFelt Life Prediction It is not difficult to estimate the felt life on the basis of different parameters, but such information is not easily available. I strongly feel all good clothing suppliersI strongly feel all good clothing suppliers have a capability to predict felt life with good accuracy. 4 Some thoughts onYankee Paper Machine Felt Life, June 2014
  5. 5. What Does the Press Do?What Does the Press Do? Simple.The purpose of a press section is to squeeze the excess water from the wet web. 5 Some thoughts onYankee Paper Machine Felt Life, June 2014
  6. 6. Press Squeezed WaterPress Squeezed Water However, the squeezed water is not clean.There are a lot of fines in it. These fines go inside the complex matrix of felt structure, and only a part of these can bestructure, and only a part of these can be easily removed through felt conditioning system. 6 Some thoughts onYankee Paper Machine Felt Life, June 2014
  7. 7. Felt ConditioningFelt Conditioning The objective of felt conditioning is to remove all trapped fiber fines from the felt. However, some do remain trappedHowever, some do remain trapped inside. Due to these trapped particles, slowly and slowly, the felt porosity goes down. 7 Some thoughts onYankee Paper Machine Felt Life, June 2014
  8. 8. Felt Wear on Suction BoxesFelt Wear on Suction Boxes When a felt passes over the suction (uhle) box, due to wear, some of the yarns (threads) of felt may get detached from the felt.the felt. That means the felt gsm should decrease over a period of time.Against this, in many cases the trapped fibers and fines are so much in quantity that the overall felt gsm increases. 8 Some thoughts onYankee Paper Machine Felt Life, June 2014
  9. 9. Yankee MachinesYankee Machines Yankee machines have two different felt configurations- Pick Up Felt (no press) Pick Up Felt (with press)Pick Up Felt (with press) If there is a press section, we use double felting, with top felt passing through MG (yankee) and touch roll. 9 Some thoughts onYankee Paper Machine Felt Life, June 2014
  10. 10. What Makes Top Felt ImportantWhat Makes Top Felt Important Being yankee cylinder the only drying cylinder, proper pressing of web on this cylinder is very important. Furthermore, the combination hot yankee cylinder and a touch roll also works as a hot pressa touch roll also works as a hot press where water is pushed away from yankee towards the touch roll (obviously through the felt). A choked felt affects production and product quality significantly. 10 Some thoughts onYankee Paper Machine Felt Life, June 2014
  11. 11. Back to the Wire PartBack to the Wire Part Stock from the headbox lands on the wire part. Most long fibers remain on the wire, while some of the fines drain through wire along with back water.through wire along with back water. As most of this water goes to fan pump slowly the fines concentration increases to an equilibrium. Finally, some fines start remaining trapped between ‘good’ fibers in the web. 11 Some thoughts onYankee Paper Machine Felt Life, June 2014
  12. 12. Fines DistributionFines Distribution As obvious, most fines from the bottom layer of paper web drain out while the fines in the upper layers remain present in the web. Imagine paper as a sandwich of two layersImagine paper as a sandwich of two layers one with and other without fines. When this paper goes to press section, water is squeezed out. Water from the side containing more fines go towards the pick up felt. 12 Some thoughts onYankee Paper Machine Felt Life, June 2014
  13. 13. Yankee FeltYankee Felt Whatever be the machine configuration- with press section or just yankee touch roll after the wire part- the yankee felt comes in contact with top layer of papercomes in contact with top layer of paper web. The top layer of paper web contains more fines. During pressing, a many fines move from paper web to felt. 13 Some thoughts onYankee Paper Machine Felt Life, June 2014
  14. 14. Yankee FeltYankee Felt If these fines are not removed effectively, the felt gets choked up too early. If we are able to improve FPR on paper machine, there will be a better fibermachine, there will be a better fiber distribution across the thickness of paper, meaning relatively lesser fines in the top layer, and better felt performance. 14 Some thoughts onYankee Paper Machine Felt Life, June 2014
  15. 15. Felt Choked with FinesFelt Choked with Fines To evaluate the quantity of fines in the felt, an old used felt just prior to take off, was washed on the machine itself as in normal operation.normal operation. Then, the felt was cut, and a small piece of this (30cmX30cm) was removed from the center. This sample was dried in oven at 105˚C and gsm was evaluated. 15 Some thoughts onYankee Paper Machine Felt Life, June 2014
  16. 16. Felt Choked with FinesFelt Choked with Fines The new felt was of 1286 gsm (design 1300gsm), and in spite of some felt yarns might have worn away, the gsm increased to 1640.to 1640. This indicates more than 356gsm fines and other material had accumulated in the felt over its lifetime. 16 Some thoughts onYankee Paper Machine Felt Life, June 2014
  17. 17. FPRFPR So, FPR plays a critical role in getter better yankee felt life. Other aspect is good felt conditioning. Felt conditioning system should be suchFelt conditioning system should be such that fines are easily removed from the felt. 17 Some thoughts onYankee Paper Machine Felt Life, June 2014
  18. 18. Felt ConditioningFelt Conditioning Periodic use of flooding shower from the inside of felt circuit may help a lot. Additionally, use of lubricants like kerosene oil helps easy removal of fineskerosene oil helps easy removal of fines from the felt. 18 Some thoughts onYankee Paper Machine Felt Life, June 2014
  19. 19. Kerosene Based CleaningKerosene Based Cleaning To recall, the procedure is as under- ◦ Stop all showers, reduce load to minimum. ◦ Spray kerosene on the felt.Typically, a quantity of 10-20% of weight of felt will be enough. ◦ Let the felt run for 5-7 minutes.◦ Let the felt run for 5-7 minutes. ◦ Now apply caustic or detergent using a shower, and again let the felt run for 2-4 minutes. ◦ Open flooding shower, and wash the felt thoroughly. ◦ After some time, apply vacuum to completely drain out chemicals from the felt. 19 Some thoughts onYankee Paper Machine Felt Life, June 2014
  20. 20. Felt Cleaning ChemicalsFelt Cleaning Chemicals Alternate to kerosene, ask your chemical supplier to suggest a good felt cleaning chemical. At first instance a felt cleaning chemicalAt first instance a felt cleaning chemical look costly, or you might feel satisfied with the existing caustic-detergent mixture, but remember this chemical may increase your felt life. 20 Some thoughts onYankee Paper Machine Felt Life, June 2014
  21. 21. Press LoadingPress Loading Yankee machines generally have limited press nips. There could be a solid double felted press, followed by touch roll and second touch roll.touch roll. In double felted press, normally a single felt passes through two nips. In case of two touch rolls also, sometimes a single felt is used to pass through both nips. 21 Some thoughts onYankee Paper Machine Felt Life, June 2014
  22. 22. Touch Roll LoadingTouch Roll Loading However, the critical part is the nip between yankee touch roll and hot yankee cylinder. A high nip pressure also means longer nipA high nip pressure also means longer nip width, more dwell time. Some of the gets moisture gets evaporated and this forces the moisture in the web towards the felt at a faster rate. 22 Some thoughts onYankee Paper Machine Felt Life, June 2014
  23. 23. Touch Roll LoadingTouch Roll Loading Furthermore, in longer nip with low basis weight papers, a lot of heat is also transferred to the felt itself, thus raising the felt temperature (and, of course, thethe felt temperature (and, of course, the steam consumption). The overall impact is more fines going in the felt, increased felt temperature, more compaction of the felt, thus reducing felt porosity further. 23 Some thoughts onYankee Paper Machine Felt Life, June 2014
  24. 24. Excess Nip LoadingExcess Nip Loading Excess nip loading also results in more felt compression each time the felt passes the nip. Have you noticed the car seat becomesHave you noticed the car seat becomes hard and compacted to early if a fat man uses the car. In the same way, excess loading reduces yankee felt life. 24 Some thoughts onYankee Paper Machine Felt Life, June 2014
  25. 25. Optimizing Nip LoadingOptimizing Nip Loading Many papermakers tend to use as high nip loading as possible in order to get best results from the nip. However, it is always advisable to run the machine at different nip loadings for smallmachine at different nip loadings for small durations (4-6 hrs.) and observe the steam consumption in yankee as well as paper surface properties. All these data should be evaluated before deciding an optimum nip loading. 25 Some thoughts onYankee Paper Machine Felt Life, June 2014
  26. 26. SummarySummary In a nut shell, three main parameters need attention if yankee felt life is too low- 1. FPR1. FPR 2. Nip Loading 3. Felt Conditioning 26 Some thoughts onYankee Paper Machine Felt Life, June 2014
  27. 27. ThankYou.ThankYou.ThankYou.ThankYou. 27 Some thoughts onYankee Paper Machine Felt Life, June 2014
  28. 28. About the Author: Born in 1968, D K Singhal is B.E., M.E. (Pulp & Paper, 1993) from Deptt. of Paper Technology, University of Roorkee (now IIT, Roorkee). He is a Certified Energy Auditor and Chartered Engineer also. With nearly 7 dozen publications, he has emphasized on development of low cost technologies and management practices for quality and profitability improvement. With publications on slideshare.net, energymanagertraining.com and paperonweb.com, he has been constantly contributing to IPPTA (Indian Pulp & PaperTechnical Association). He is also serving IPPTA as a member of Editorial Board.Board. An initiative by D K Singhal, a cyber campaign initiated against unjustified targeting of paper industry by “Idea” mobile, in their “Sirjee” advertisement campaign, after which this advertisement was taken off air. He also moderated aYahoo group,“PaperTechnology” with nearly 360 members from India and abroad to discuss problems related to pulp & paper making for five years. He can be contacted at deveshksinghal@gmail.com 28 Some thoughts onYankee Paper Machine Felt Life, June 2014
  1. A particular slide catching your eye?

    Clipping is a handy way to collect important slides you want to go back to later.

×