Carding Calculations in Spinning Mill

 

Sliver wt. = 4. 01 gram / metre.

= length in yards/840 x 454/weight in gram

production / card / Shift of 8 hours in kg.

= 10 x 3. 14 x 27 x (1/36) x (1/840) x (1/0. 147)x(1/2. 205) x 60 x 8 x (85/100) = 35. 3 kg / 8 hour

3) Lap Hank = 0. 0013; Mechanical Draft = 85; Waste = 6%; Doffer
Speed = 20 RPM; Efficiency = 85%; Production/8 hr = ?

Actual draft of card = SliverHank / Lap Hank

The removal of waste during the operation, reduces the quantity of material passing through and there is less to be delivered.

Actual draft = Weight per yardfed/wt. per yard delivered Mechanical draft (is calculated from gearing) is determined, by use of the actual draft (required) and waste%. So, Mechanical draft is always less than actual draft.

Mechanical draft = Actual draft x ((100-waste%) / 100) 85 = Actual draft x (100-6)/100 Actual draft = 85 x (100/94) = 90. 4

Sliver Hank = Actual draft x Lap Hank = 90. 4x0. 0013 = 0. 117 Production in kg/8hr. = 20 x 3. 14 x 27 x (1/36) x (1/840) x(l/0. 117) x (1/2. 205) x 60 x 8 x (85/100) = 88. 8 kg.

4) Lap weight = 400 gram / metre: Sliver wt. = 4. 05 gram / met

DCW = 17 T: waste = 6 %: efficiency = 90 % Doffer (27 inch dia) = 8 RPM. Draft constant, production ?

Actual draft = wt per mt fed / wt per mt delivered

= 400 / 4. 05 = 98. 7

Mechanical draft = actual draft x ( 100 - waste % )/ 100

= 98. 7 x (100-6) / 100 = 92. 8

Draft constant = DCW x mechanical draft 17 x 92. 8 = 1578

Sliver wt = 4. 05 gram / mt sliver hank = (length in yard / 840) x 454 / wt in gram
= 1. 09/840 x 454 / 4. 05 = 0. 145

Product ion in Kg/8 hour of carding= 8 x 3. 14 x 27 xl/36 x 1/840 x 1/0. 145 x 1/2. 205

x 60 x 8 x 90/100 = 30 Kg/8 hour.

5) Sliver Hank = 0. 15; Lap weight = 392 gram/metre

Doffer Dia = 27 inch; waste = 3% Plate wheel = 120T Side shaft bevel = 34T; Doffer wheel = 34T; Peed Roll Dia

=2. 25 inch

Draft change wheel = ?

Draft Change wheel = Draft constant/Mech. draft

Mech. draft = Actual draft x (100 - waste %)/100

Actual draft = Hank delivered/Hank fed = 0. 15/0. 0015 =100

Lap weight = 392 gram/met.

Lap Hank = (length in yard/840) x (454/wt. in gm)

= (1 x 1. 09)/840 x (454/392) = 0. 0015 Mech. draft = 100 x (100-3)/100 = 97

To find Draft constant, let we assume The speed of the feed roller is kept as 1 Draft constant

= 1 x (120/DCW) x (34/34) x (27/2. 25)

= 1440

Draft Change Wheel = 1440/97 = 14. 3T

6) Height of Empty can = 6 kg; wt. of Pull can = 14kg Sliver Hank = 0. 14; Doffer (27 inch Dia) = 18 RPM; Efficiency = 80% Time Required to fill one can =? Sliver weight = Full can wt. - Empty can, wt. =14-6=8 kg.

To calculate the time Required to fill one can or to produce 8 kg (Production) is,

= Doffer Speed x Doffer Dia x 3. 14 x 1/36 x 1/840 x 1/Sliver Hank x 1/2. 205 x Time Requirement to produce 8 kg x Efficiency/100

Time requirement to fill one can (To produce 8 kg) = 8 x (1/Doffer speed) x (1/Doffer dia) x (1//3. 14) x

(36 x 840) x (Sliver Hank) x (2. 205) x (100/Efficiency) = 8 x 1/18 x 1/27 x 1/3. 14 x 36 x 840 x 0. 14 x 2. 205 x 100/8O = 61 Min.

7) Draft Constant = 2100; DCW = 21T; Waste = 6%

Lap fed =14 kg/40 yard; Doffer (27 inch dia) = 13 RPM Efficiency = 85%; Production= ? Lap weight = 14kg/40yard

Lap hank = (Length in yard/840) x (454/wt in gram) = (40/840) x (454/14000)=0. 0015 Mech. draft = Draft constant/DCW = 2100/21 =100 Actual draft = Mech. draft x [100/(100-waste %)]

= 100. X 100/94 =106 sliver hank = Actual draft x lap hank = 106 x. 0015 = 0. 159 i. e.. Production / 8 hour in kg =13 x 27 x (22/7) x (1/36) X (1/840) x (1/0. 159) x 60 X 8 x 85/100 x 1/2. 205 =42. 4 kg/8 hour

8)Calculate the time taken for a card to exhaust a Lap with following datas.

Lap weight = 35lbs; Sliver Hank = 0. 16; Efficiency = 85 % Waste 1 lbs: Doffer(27"0)=lO RPM Sliver weight = (lap wt- waste) =35-1= 34 pound i. e., production of the sliver from 35 lbs lap is 34 lbs. production in lbs (34) at 85% efficiency.

=Doffer speed X Dia. of doffer x 3. 14 x( 1/36) x (1/840) x (1/sliverhank) x 85/100

x time to produce 34 lbs (or) Time to exhaust one lap.

9) In a blow room the production is 10. 000 lbs/shift of 8 hour calculate the number of cards you will allocate with the given details.

Doffer speed = 20 rpm Efficiency = 90%

Sliver hank = 0. 12 Doffer diameter = 27 inch

Waste = 5 % Solution:

Total lap weight requirement per card per 8 hours

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Steps to be taken while changing the length & hank of the lap

 

Lap Hank= lap length in hanks/weight in lbs.

To change lap hank, the feeding to the sctucher is altered by following methods.

i) feed roller speed is changed by altering the position of the cone drum belt by trial & errer method to bring the required Lap weight & lap hank.

ii) front sheet & back sheet position of the reserve box of the

Hopper feeder & swing door position is altered i.e. weight/unit

length fed to scutcher is altered depending on the required lap hank. For example, to get more wt/ yard of lap front sheet should be moved forward, to increase the volume of the reserve box to get heavier lap.

iii) in automatic scutcher, press button switches are provided for the regulation of the lap weight per yard and lap hank through a servomoter on the P.I.V. drive . The current postion of the PIV drive and the degree of regulation are clearly indicated on a scale. It is possible to determine the optimum

Setting very quickly in case of lap hank change overs. In case of automated scutcher, only the basic lap weight per yard is set by using the corresponding press button switches. All adjusments are automatically carried out by the lap weigher.

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Cleaning efficiency of Blowroom - Calculation

Trash% in cotton is estimated by shirley trash Analyser. Cleaning Efficiency, depends on the following factors.

Trash% in feed,

Amount of preopening,

Speed of Beater,

Maturity of Cotton,

Nature of Impurities

Settings, etc.,

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