SOME
ESSENTIAL CHECKPOINTS IN BLOWROOM
Mixing Room
1. Check whether blend consistency is
maintained, i.e. at any point of time, the amount of cotton of each variety
that is fed should conform to the mixing proportion desired. Very often
supervisors only check up that the required total number of bales is consumed
in the shift, but it is more important to see that the proportion of each
variety taken feeding compares with the set proportion.
2. The level of stock in the different
bales taken for feeding should be about the same at any point of time.
3. Visually check whether the setting
between the inclined spiked lattice and evener roller is uniform along the
width of the machine. Some idea about this can be had by comparing the amount
of cotton dropping off from the extreme ends of the inclined spiked lattice.
4. Ensure that the soft waste added to
the mixing is free from oily and dirty sweepings and the roving ends and bonda
are well opened.
1. Magnets installed in the line should be
checked for their effectiveness and condition. If too much
accumulation of metallic substances is found,
their cleaning frequency may have to be improved
as there is risk of a part of the metallic
substances being carried forward with the cotton.
2. Check the condition of grid bars at all
beating points. Gird bars should be smooth and clean and
should not be choked or bent.
3. Check beater bades for sharpness and freedom
from burrs and damage.
4. Check the condition of the lap fringe. This
will thorw light on whether the setting between the
beater and roller is correct, whether the grip
on the lap sheet is proper and also whether the
opening of the material at the earlier stages is
adequate.
5. Inspect the trash chamber to check the
richness of waste and also to observe whether the trash box
is getting overfull. If the latter is observed,
there is danger of trash getting recombined with the lint
and the schedule for waste removal will have to
be accelerated. If excessive lint loss is observed, a
detailed quality control study will have to be
undertaken to look into the causes and remedies.
6. Check condensers for the condition of the
screens. Screens that have become dented, or with bent
or broken wires, collect and deliver stock
unevenly, resulting in high lap variation at the scutcher.
7. Ensure that the pedal levers do not meet with
any obstruction during working, as this not only
affects the pedal weighting, but also the feed
regulation. A safe clearance should be maintained
between the material is in process and in no
case should the pedals rest on the cross bar.
8. Check whether the level of material in the
hopper reserve box is as per the prescribed level. Also
check at what level the signals for starting and
stopping the supply are given. Under normal conditions, these should not vary
widely. If the two levels are found to differ widely, a detailed check up of
the swing door mechanism, the working of the solenoids and microswitches will
have to be undertaken.
1. Through the glass panel or side window, check
the level of material in the reserve box. If the level is not found to conform
with the standard marked level, prompt corrective measures are to be taken.
2. Open the come drum box and check the position
of the belt. The belt should operate in the central region most of the time.
3. The width of the belt fork should conform to
the width of the cone drum belt.
4. Check for loose
links in the pedal regulating motion and ensure that the pedal lever is
properly weighted; otherwise transmission of motion from the pedals to the cone
drum belt will not be faithful.
5. Worn-out leather
linings in cages lead to excessive loss of good fibres in the gutterfly.
Careful check should therefore be kept to prevent such a condition.
6. In case lap felters
are being used, care should be taken to see that they are set properly.
7. Check the leather
lining of the brake. Worn-out leather linings lead to laps of improper build.
8. The load on the
calender rollers is transferred to the calender roller shaft through the
calender toller bearings. Consequently, worn-out bearings need prompt
replacement.
9. Unroll a couple of
doffed laps for a short distance to see whether the lap is properly made. The
sheet should be able to unroll cleanly without splitting and at the same time
the sheet should be of uniform thickness without holes and other defects.
10. Check selvedges of
lap for thin, ragged edges. Any obstruction in the passage of material
interferes with even flow and shows up as irregularities in the edges of the
lap.
11. Observe the lap
for conicity in build. In case such a condition is observed, suitable steps
(detailed in chapter 11 on “Common Defects in Blowroom Laps”) will have to be
taken to offset the conicity.
12. Where lap guards
are used, care should be taken to see that they do not rest on the lap as this
can lead to imperfections in the lap build and also disturbance to fibre tufts
in the lap.
13. The flutes of
shell rollers should not be too rough or have burrs, as this causes snatching
of tufts of fibres from the calendered sheet; the shell rollers should not be
too smooth either, as this impairs the grip of the shell rollers on the lap. To
smoothen out these rough edges it is recommended that they be polished with
pumice stone periodically.
14. Ensure that the
lap width is about 5 cm less than the card width. Carelessness in this respect
give rise to imperfect selvedges of the web and also improper carding of the
edges of the lap.
15. In the case of
mills using the breaker scutcherfinisher scutcher sequence, ensure that the
sizes of laps on the creel of the finisher scutcher are staggered. If all the
laps are of the same size, they will all empty cut at the same time resulting
in greater risk of singleings.
Thus, if the
technicians make it a point to inspect the above-mentioned checkpoint during
their
round in the
department, they can bring about significant improvement in the line in course
of time. It is expected that it will normally take the supervisor about an hour
to complete the supervision of the one line.
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Submitted by : Mr. Lav Ahuja , Final MMTT (01- 02 Batch)
DKTE. Mail : lavahuja@hotmail.com