Metalock Blog – News onsite engineering services and all things metalock

PRESS RELEASE

July 10th, 2010

Faced with the task of machining the 5.2 metre diameter base table on a raw mill at Lafarge’s Dunbar works,Coventry firm Metalock Engineering UK designed a special machining rig to restore the main surface that hadsuffered wear. This is the only cement works in Scotland and £35 million has been invested in the factoryresulting in a rise in production to one million tonnes a year.

The revolving table supports a baseplate that forms one of the crushing surfaces. Others come from two pairsof steel tyres(rollers) weighing 75 tonnes each that run in mating grooves on the baseplate. When in operationthe tyres are subjected to 130 bar pressure to effectively crush raw limestone to a fine powder for the manufactureof cement clinker. The pressures and vibration are enormous and severe fretting corrosion had taken placebetween the table and the baseplate since the mill had been installed in 1985. The mill had not been refurbishedbefore and the fretting corrosion was causing fixing bolts to shear due to substantial undesirable movementbetween the baseplate and the table.

Metalock was recommended by the mill’s chief mechanical engineer who had previous experience of workingwith the company when he was at the Llanwern steelworks in South Wales.

Metalock’s machine design comprised an outer support track, feed rack and feed assembly all of which waswelded to the circumference of the 5.2m diameter base table after the baseplate segments had been removed.The assembly was aligned by laser and revolved around a main bearing hub located in a 640mm diameter holein the centre of the table. A 3 metre long cross slide with its own feed and outer support mechanism, designedto rotate at 1 rpm, was attached to the hub. On the cross slide was an hydraulically driven milling head whichenabled Metalock to remove material more quickly and provide a better finish than if a single point tool hadbeen used.

To replace the material that had been machined from the surface of the base table, Metalock produced twelvenew 4mm thick stainless steel segments. These were predrilled to allow spotting through and subsequentdrilling and tapping of 21 holes for M6 countersunk screws to fix each segment.

The purpose of the stainless steel segments was so that, if necessary, they could be replaced in future ratherthan having to machine further material from the base table. Stainless steel was selected to better resist anyfuture fretting corrosion. The fixing bolt configuration for the crusher track plate was also changed.

The baseplate was changed just over 12 months after the Metalock operation, and no marks on the main tableindicated that the modification was successful.

Metalock’s machine had an outer supporttrack, feed rack and feed assembly, all ofwhich was welded to the periphery of the5.2 metre diameter base table. It revolvedaround a hub at the table’s centre.

Contact:
Metalock Engineering UK Ltd.
Unit H5 Pilgrims Walk, Prologis Park, Coventry CV6 4QG ENGLAND
Tel: +44 (0) 2476 338205
Fax: +44 (0) 2476 360190

PRESS RELEASE

July 10th, 2010

To eliminate the risk of a cracked casing on one of its china clay drying kilns Imerys Minerals, formerly EnglishChina Clays, called upon Metalock Engineering to in-situ machine one of

Read more about Imerys Minerals – rotary kiln tyre regrinding

Contact:
Metalock Engineering UK Ltd.
Unit H5 Pilgrims Walk, Prologis Park, Coventry CV6 4QG ENGLAND
Tel: +44 (0) 2476 338205
Fax: +44 (0) 2476 360190

PRESS RELEASE

July 9th, 2010

Having ascertained that the slew ring on its 20 year-old cement unloader was in need of replacement, the management of Forth Ports, Leith called in Metalock Engineering, Coventry, to machine

Read more about Forth Ports – Cement Unloader Slew ring/ lifting rams

Contact:
Metalock Engineering UK Ltd.
Unit H5 Pilgrims Walk, Prologis Park, Coventry CV6 4QG ENGLAND
Tel: +44 (0) 2476 338205
Fax: +44 (0) 2476 360190

PRESS RELEASE

July 8th, 2010

The backbone of the baked bean production process is sterilization of the finished product in sealed tins and anybreakdown in the plant used could have very serious consequences. As a

Read more about Bean Processor – rotary sterilizer shaft recovery

Contact:
Metalock Engineering UK Ltd.
Unit H5 Pilgrims Walk, Prologis Park, Coventry CV6 4QG ENGLAND
Tel: +44 (0) 2476 338205
Fax: +44 (0) 2476 360190