Mg Dryer Cylinder for Tissue Paper Machines

Product Description

Product Description

Dryer Cylinder Description 

Dryer Cylinder is divided into :Cast Iron Dryer Cylinder,Steel Dryer Cylinder,Yankee Dryer Cylinder
All dryer cylinders, heads and journals are made of special cast iron. Separate journals are bolted onto the dryer heads. Dryer shells are ground on the outside and turned on the inside. All dryer journals with steam or condensate pipes have insulation sleeves. The inner surfaces have grooves for the stationary siphons. The front side ends of all dryers contain manholes.
Cast iron material are excellent in durability.This is because the free form flake graphite in the cast iron material ensured its high corrosion and erosion resistance. The cast iron also has good fatigue strength under the pressure roller forces. At the same time, cast iron itself has a good surface performance, does not need metal spraying treatment like steel dryer.

             Cast Iron Dryer Cylinder              Yankee Dryer Cylinder                        Steel Dryer Cylinder 

A Yankee dryer cylinder is a pressure vessel used in the production of tissue paper. On the Yankee dryer cylinder, the paper goes from approximately 42-45% dryness to just over 89% dryness. In industry, MG cylinders or Yankee dryers are primarily used to remove excess moisture from pulp that is about to be converted into paper. The Yankee cylinder can be equipped with a doctor blade and sprayed with adhesives to make the paper stick. Creping is done by the Yankee's doctor blade that is scraping the dry paper off the cylinder surface thereby crêping the paper. The crinkle (crêping) is controlled by the strength of the adhesive, geometry of the doctor blade, speed difference between the yankee and final section of the paper machine and paper pulp characteristics.

Structure of Dryer Cylinder 

The main parts of the dryer include: Shell,Turbulator bars,Syphon, Shell head,Manhole cover,bearing ,Head cover, Steam Joint .

Heat Transfer from Steam to Paper

At present, most paper machines use steam heating dryer cylinder to provide heat energy, in the way of heat conduction, heat energy is transferred to the paper through the dryer. The humidity is generally from 60% reduced to 5% when the paper coming out from the dryer section, and then into the glazing machine.

Grooved internal surface

We provided grooved internal surfaces Yankee dryer for customer choice. The Grooved Yankee dryer internal face is machined with radial grooves, condensed water accumulates in the grooves during running. It is used with a condensate extractor, each siphon on the extractor is located in the groove so that the condensed water can be effectively discharged. Under the same working condition, the grooved internal surface has good heat transfer efficiency and less steam loss than the smooth internal surface because of the reduced thickness at the root of the shell. This design can be applied to the paper machine's speed within 2200m/min.

Condensate discharge device
Siphon selection is an important factor to maximize drying rate and reduce temperature variation.

Stationary Siphon

The pressure difference requirement of stationary siphons is relatively low. The pressure difference required for cantilever stationary siphon does not increase with the increase of paper machine speed.
Condensate water can be discharged without use high pressure steam power in the case of air inlet pressure and pressure difference close to or lower than atmospheric pressure, it can reduce the corrosion.
Cantilever stationary siphons are usually suitable for medium to high speed paper machines.

 

Condensate extractors

The condensate extractors applied on grooved internal surface Yankee dryer cylinder.

It is supported by solid structures which ensure the required frame rigidity.

The entire system is designed to compensate thermal expansion and provide high wear resistance.

Turbulator bars

          The turbo bars helps to increase the heat transfer rate by generating resonance waves in the condensate film.

Advantage

1)Applied to smooth internal surface Yankee dryers

2)Increased condensate turbulence

3)Improved heat transfer and drying capacity

4)Improved surface temperature profile
 

Production Line of Dryer Cylinder 

Technical parameters:

Diameter	Design Pressure Mpa	Material	Hardness	Width	Shell Thickness	Roughness	Working speed
1500	0.3-0.8	HT250-300	190-240	350-10000	25-32	0.2-0.4	200-1200
1800	0.3-0.8	HT250-300	190-240	350-10000	28-36	0.2-0.4	200-1200
2000	0.3-0.8	HT250-300	190-240	1350-5000	30-40	0.2-0.4	200-1200
2500	0.3-0.8	HT250-300	190-240	1350-5000	32-47	0.2-0.4	200-500
3000	0.3-0.8	HT250-300	190-240	1350-5000	37-56	0.2-0.4	200-600
3660	0.3-0.8	HT250-300	190-240	1350-5000	40-65	0.2-0.4	200-1200
3680	0.3-0.8	HT250-300	190-240	1350-5000	as required	0.2-0.4	200-1200
≤1500	0.3-0.5	HT200-250	190-240	1350-5000	18-27	0.2-0.4	200-1200

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