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Installation and Commissioning

 


CST recommends that installation of their belt weighers and weigh feeders is always done with CST supervision. Correct installation is pivotal to a smooth and efficient commissioning process, and correct functioning of our precision weighing equipment. It is not common for site staff to have the necessary experience and knowledge required to appreciate the importance of correctly following ALL aspects of our installation procedures.

Inspection and preparation of the area into which the belt weigher weigh frames is to be installed is critical. Sometimes existing formwork or piping on the conveyor needs to be re-routed if it will obstruct the belt weigher. Pipe work or any structure rubbing against the weigh frame can directly effect weigher accuracy.

When CST supervises the installation, we will make a preliminary site visit to discuss the work, and assess whether any of the existing fixtures need removing or re-positioning.

Any work required on the Conveyor structure is an engineering issue. It may be that additional supports are required for the belt weigher, or the conveyor structure itself may need parts removed. It is necessary that an engineering analysis be done to ensure structural integrity of the conveyor is not compromised. We will send out our Design Mechanical engineer or Design Draughtsman to measure up, assess changes, and whether additional strentheninging structures are required to support the changes.

 

Installation without CST Supervision

 

Usually this option is chosen for cost saving reasons, however this cost benefit is negated in those situations where CST arrives on site to commission the belt weigher or weigh feeder and the weigher has not been installed correctly. The negative impact on a customer is that commissioning time blows out, or because of downtime limitations and pressures, the job gets rushed, sometimes with less than optimum results. One of the more common problems encountered when CST is not involved in the installation, is that the weigher is not positioned on the conveyor exactly as per our drawings. This requires reworking and repositioning of the weigher, with the flow on impact of pressurising the time available for commissioning, or worse, extending the downtime.

It is important to understand that CST weighers are specifically designed for each site application. Therefore, even though site staff may have installed weighers before, even other CST weighers, the assembly for this particular weigher could be different, and it is important to get this right.

 

Commissioning

 

Commissioning of CST belt weighers or weigh feeders is a condition of our supporting our accuracy guarantee.

Mechanical Components:

  • Installation of weigh frame is checked thoroughly. Adjustments are made where necessary. All measurements are checked against drawings, to ensure the weigher is square and situated correctly.
  • SIP masses are checked for correct installation and fit.
  • Belt Weigher Alignment – Weigher is checked to ensure that it is perfectly aligned in the centre of conveyor. If not dead centre, belt tracking issues are created, which can affect way load is carried, and accentuate normal belt movement. The effects can have a negative effect on zero stability.
  • Load cells are fitted, making sure location rods are in place and correctly tensioned (as tightly as possible).
  • Roller Alignment – this is the most critical part of the mechanical commissioning process. This step requires the belt to be lifted, and takes longest time. CST procedure is to run 2 string lines / roll, plus a centre line.
    NOTE: Tolerance accuracy required for idler alignment is to within 0.3mm – this requirement, which is critical to accurate weighing, is not something appreciated by site technicians.
  • Measurement of Belt Length – of all the commissioning steps, this is the one that requires the most care. It is imperative that the belt is measured correctly. CST uses a steel calibrated tape measure, it is the only measuring tool accurate enough. For OHS and accuracy reasons, CST technicians will not use a jockey wheel.
  • The impact of incorrect measurement of belt length is a direct transfer of that error to the belt weigher accuracy e.g. A 0.1% error in belt length measurement leads to a 0.1% weighing accuracy error. Click here to see a more detailed explanation - weigher standards.