doublebacker issues by croker

7/22/2019 Doublebacker Issues by Croker

1/37


2/37

OVERVIEW


3/37

THE DOUBLEBACKER

What does it do? Holds the liner and web together with minimal pressure

just to make a bond across the board and edges

What is needed

Starch to gel, thus tack then loose moisture

Plate temperature is critical

Belt speed must be synchronized wit the board speed

Top and bottom belt speed must be within 5% of each

Plates must be level

Weight rolls must be in right order


4/37

LEAD - IN

No wave or flutter of liner or singlefaced web permitted


5/37

DOUBLEBACKER PROBLEMS Caliper loss

Edge Bond

Blisters

Temperature - Gradient and profile

Changing heat available

Special flutesE flute

Special liners - preprint


6/37

HOT PLATE DEFELECTION

1.8 mm =


7/37

PLATE DEFLECTIONNEW BELT


8/37

INFUSION HEATING -3


9/37

EXPRESS - Steam Chests

Single fusion cast iron

Rounded internal corners on steam path for

optimal flow and elimination of vortexes

Sec A - A

TM


10/37

The heating section of the DoubleFacer can be supplied in different versionsaccording to the plants performance and production requirements.


11/37

BEARING WEAR


12/37

CHECKING TEMPERATURE


13/37

HOT PLATES -

TEMPERATURES/STEAM Desired hot plate temperature

Over 325 degrees F ( 161 degrees C)

Cooler Temperatures are being used dependent on

papergrade, flute, Plants mode of operation (cooler vs.

hotter)

Steam pressure - 150 psi and above for 325 degrees F

Pressure must be adjustable to run the cooler

corrugating concept


14/37

CHECKING THE TEMPERATURE


15/37

CHECKING WITH A PYROMETER


16/37

HOT PLATE LUBRICATIONLiners that are subject to drag also create high power demand

Symptoms

Variation in cut length

Increased Amp draw on DB drive

Remedies - applied when the current demand exceeds a set point

By wax bar

By wax emulsion spray systems


17/37

WAX BAR AT THE D/Ber


18/37

HEAT TRANSFER


19/37

LEVELING HOT PLATES


20/37


21/37

CHECKING PLATE LEVEL


22/37

WEIGHT ROLLS


23/37

WEIGHT ROLLS


24/37

PRESSURE BY AIR


25/37

PRESSURE FOOT SYSTEMS


26/37

BELT PROBLEMSBeltWorn

TensionBelt dirty

Belt weaving

Belt marking the board

Dirt

Lacing


27/37

BELT TRACKER


28/37

WORN BELT


29/37

BELTS CAN CAUSE QUALITY PROBLEMS

SYMPTOM CAUSE REMEDY

Edge bond worn or plugged belt measure or clean

Edge crush weight rolls adjust

Edge trim waste check belt weave adjust

Damp board plugged belt clean

Sheet length variation dirty belt clean

Marks on board starch build-up clean

Indentation on board starch build-up clean

Board weave check belt guide re-lace belt/tension


30/37

BELT MAINTENANCEBelt cleaningBelt wear

Belt life

Belt starch pick -up

Belt tracking

Belt splicing

Belt tensioningBelt lagging

Belt speed -top and bottom


31/37

BELT CLEANING


32/37

RE-INFORCEMENT TAPE


33/37

BELTS AND BELTLESSPurpose of a belt - apply pressure -assist bonding- apply pulling for traction

Types of belts - a. Heavy interwoven cotton 5/16 thick

absorbs moisture

b. Synthetic needled felt type 1/2 weight

Steam passes through

c. Woven polyester belt

Beltless Most suppliers since 1995 offer

a. Fully beltless with vacuum traction section

b. First section beltless, traction section uses belt


34/37

BELTLESS -1


35/37

BELTLESS 2


36/37

VACUUM TRACTION SECTION


37/37

Flat Crush vs Moisture

doublebacker issues by croker

Documents