Other OEM PartsAssemblies
Ball Mill Shell Assembly with Hollow Trunnion
Horizontal ball mill shell assembly: a welded drum, a bolted end cover and a machined hollow trunnion that carries the grinding charge and lets material and air pass through.
Structure and machining
The assembly is made of a shell rolled and welded from heavy steel plate, an end cover with a large flange, and a machined hollow trunnion. Bolt holes are laid out along the shell wall in line with the liner pattern, clamping the wear plates against the inside surface, so worn liners can be replaced without cutting the shell.
The end cover is bolted to the shell through the large flange. Flange faces, bolt holes and the trunnion journal are machined after welding, which makes the trunnion the rotation datum and keeps the drum concentric with the main bearings.
Duty and operating conditions
Steel balls and rods inside the drum are lifted by friction and centrifugal action and fall back onto the charge, grinding material to the target fineness by impact and attrition. The trunnion also serves as the passage for feed material, air flow and discharge, while the drum takes repeated impact loads in continuous heavy duty. Typical applications are mineral processing of ferrous and non-ferrous ores, cement and building materials, metallurgical slag recovery and coal-fired desulphurisation lines.
Assembly and inspection
Final assembly, liner fitting and non-destructive testing are carried out with the drum resting on a 150 t self-adjusting welding roller stand. The stand turns the shell slowly, so full-perimeter welding, liner bolting and inspection are done from a fixed working position.
Before shipment the flange joint fit and bolt hole positions are checked, together with trunnion journal dimensions and radial runout; welding and dimensional records are issued with the unit. Shell diameter and length, liner hole pattern, trunnion dimensions and end cover type are built to the customer's drawings and duty conditions.
Specifications
- Type
- Horizontal ball mill shell assembly
- Main components
- Shell, end cover, hollow trunnion
- End cover joint
- Large flange, bolted
- Liner fixing
- Bolt holes through the shell wall
- Assembly stand
- 150 t self-adjusting roller stand (tooling, not part of the mill)
Common questions
- Can you machine this part to my drawing?
- Yes. Every part is quoted from the drawing. Send a PDF, DWG, DXF, STEP or IGES file with the material, quantity and any inspection requirements, and we reply within one working day.
- How are the material and heat treatment decided?
- They follow your drawing. The specification table shows the range normally used for this part type; the final material and heat treatment are confirmed with the quotation.
- What lead time and inspection come with the part?
- Lead time is set in the quotation and depends on material, size, quantity and inspection scope. Material verification, in-process checks and final inspection records are archived with the part, and any extra certification is agreed before production.
- How is the part packed for export?
- Export parts are rust-proofed and packed for the transport method and destination confirmed in the quotation, with lifting points and markings agreed before dispatch.
Every part is quoted from the drawing itself, not from a size band. Send it over and we answer with the process, the lead time and the tolerance we can hold.
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