Abstract
This standard specifies the technical requirements for cast iron baking cylinder for paper machinery. It is applicable to the baking cylinders with a nominal diameter of not more than 2000mm and a nominal length of less than 8000mm used in paper manufacturing machinery. This standard specifies the classification and marks of cast iron baking cylinders, technical requirements, inspection rules, requirements for appearance, packaging, transportation and storage of cast iron baking cylinders.
The standard is the fourth part of the comprehensive standard of paper machinery (ZBY 91 003-88).
Technical Requirements
1. The material of cylinder should be selected according to the requirements of nominal working pressure, temperature, use environment and action conditions.
2. The wall thickness of cylinder should conform to the requirements of nominal working pressure, temperature, use environment, action conditions, mode of connection, size and weight.
3. The cylinder should possess the features of strong mechanical strength, corrosion-resistance and performances of heat stability.
4. The connection flange should contain enough stress margin, which easily cause the fracture or fracture source when it is under overload or hydraulic pressure overload.
5. The flanges of the bigger diameter shall be within the limit of the upper limit of the closed dimensional shape tolerance in order to guarantee the sealing reliability of the cylinder.
6. The surface of cylinder should be well-finished, smooth and clean. If there are welding marks or blemishes, they must be filled up in order to guarantee that the surface of cylinder is completely met the requirements of machined surface.
7. The sealing device of the cylinder should possess reliable performance with the features of good tightness and wear-resistance.
8. The welding line should has closely reliable quality and good mechanical strength.
Inspection Rules
1. The inspection should be taken after the cylinder being manufactured and before leaving the factory.
2. The check should include the inspection of inner and outer surfaces, aircraft welding line, sockets, forging and machining seam, appearance and coating quality with the requirements of the drawings.
3. The main size should pass the test by measuring instrument and the geometry of cylinder should pass through the rollers flatness.
4. The hydrostatic pressure test should be done at the rate of 1.5 times of the nominal working pressure.
5. If the passage orifice is equipped in the cylinder, the air leaking test and the bubble test should also be included.
Appearance Requirements
1. The cylinder wall should be only according to the drawing or embossment given by the factory or indicated by the manufacturer.
2. For making allowance of cylinder body on the cutting edge of the flange, this allowance should between 2.5mm-3.0mm.
Packaging, Transportation and Storage Requirements
1. The cylinder should be protected with soft material, and each one should keeps its own quality certificate, packing list and certificate for product tracking.
2. The cylinder should be put in the wood box.
3. The wood box should be handled carefully to avoid any damage or deformation caused by loading, transporting, lifting and vibration.
4. The cylinder should not be exposed in outside and be stored in a dry and clean environment.
