Yankee Dryers

Our Yankee Dryers manufacturing line presents the capability to produce cylinders with diameters up to 7.320 mm (24 ft) and face length up to 6,500 mm.

Therefore, we are now able to attend to any demand from this paper industry segment and definitely have established ourselves in the market as the major supplier of steel Yankee cylinders in Latin America.




Main features

Shell: manufactured with carbon steel plates with high mechanical resistance under ASTM standard. All welded joints are totally inspected by means of ultrasonic and x-ray inspections and heat treatment (stress relief).

Head Covers: mounted with cap-screw or welded to the cylinder shell. All materials are totally controlled by means of ultrasonic inspection and heat treatment (stress relief)

Central stay: manufactured with carbon steel plates under ASTM standard. All welded joints are totally inspected by means of ultrasonic and x-ray inspections and heat treatment (stress relief). Steel cast journals with total control of the physical properties of the materials.

Condensate extractor: fitted with multiple soda straw which are manufactured on stainless steel with micro casting nozzle (high hardness). Special system for fixing the straw pipes with easy adjustment of the gap (distance between nozzle and internal shell surface).

Metal coating: with high-hardness for extended useful life and reduced thickness allowing high heat transfer to the sheet paper.

Manufactured according to ASME North American Code or PED European standard.


Cylinders advantages

NO rupture risk due construction in carbon steel

Increased production: : HIGHER HEAT TRANSFER UP TO 35% AS COMPARED WITH CAST IRON CYLINDERS resulting in higher paper evaporation ratio

Innovative condensate extraction system

Higher reliability with no risk inherent to the casting process, such as porosities or discontinuities

Two construction options for Head Covers: mounted with cap-screw or welded to the cylinder shell

Metal surface with high hardness resulting in better creping quality

Excellent temperature profile

Steel plate material allows cylinders construction with any required diameter

Easy transportation: journals may be transported disassembled thus reducing the maximum load height


Assembling Features


Welded or Bolted Heads

Welded heads

Bolted heads



Grooved internal surface

The Hergen's Yankee Dryer Cylinders are provided with grooved internal surfaces. The grooved alternative offers more advantages as compared with the smooth one. When the grooved alternative is combined with the steel construction the benefits are even greater.

Advantages for STEEL construction with GROOVED internal surface

Due to the mechanical properties of carbon steel plates, shell thickness may be significantly reduced in comparison with a cast iron construction under identical operating conditions

This is an important advantage for a Yankee cylinder since a reduced shell thickness offers less resistance to the heat transference.

When one Yankee cylinder is manufactured with steel plate and in additional is machined with a grooved internal surface, the heat transfer is even greater due to the reduced thickness at the shell root.



Thermal insulation

Dryer cylinder loses heat through its heads which leads to a continuous energy waste. Cylinder thermal insulation minimizes this loss resulting in considerable energy savings

Additionally, thermal insulation also increases operator safety due to the significant temperature reduction on the outside of the insulation

Benefits

Steam saving from 3 to 5%

Increase operator safety

Low cost investment



Condensate extractors

The condensate extractors are supported by solid structures which ensure the required frame rigidity.
The entire system is designed to compensate thermal expansion and provide high wear resistance.



 

Turbulence Bars

The turbulence bars function is to break the condensate film formed on the inner cylinder surface thus allowing higher convection between the steam and the cylinder for better heat transfer and consequently higher evaporation rate.

Benefits

Increases cylinder drying capacity

Improves drying/moisture profile

Easy installation

Low cost investment




Quality control

Quality certificate for all steel plates used in the manufacturing – mechanical and chemical properties

Quality certificate for cast parts – mechanical and chemical properties and metallographic structure

Cylinder construction in compliance with strict manufacturing standards (ASME, PED or others, as required)

Ultrasonic inspection for every shell and cover head

Dimensional inspection after cylinder shell manufacturing

Ultrasonic inspection for all welding seams

Heat treatment for stress relief

Strict dimensional control in all cylinder manufacture stages

Hydrostatic test in compliance with ASME and PED standards

Ultrasonic inspection for all cap-screws


 

Easy transportation

Journals may be disassembled from the Yankee cylinder. Our team executes journal assembly at the customer’s facility. This makes cylinder transportation easier with considerable reduction of the maximum height



Manufacturing line