|100% tracability and compliance with ISO 9000 quality requirements.
|Batch records may not tie up with actual dosage as flow meter inaccuracy cannot be recorded.
|Scales are properly calibrated and traceable to national and international standards and tolerances. Batch computers hold a record of what has been weighed ensuring traceable confirmation of the volume dispensed.
|Flow meters are not calibrated in the strict compliance sense. Supply companies simply do a check and issue a dosage check document. Although the batch computer holds a record of what has been requested from the flow meter there is physically no confirmation that what was requested is what has been dispensed.
|Admixtures are pre-weighed then held in the hoppers ensuring rapid discharge with no impact on batch cycle.
|Admixtures are batched directly into concrete mix, which could slow batching cycle
|Admixtures can be dosed at any stage of batching and in multiple dumps – thereby achieving optimal performance.
|Admixtures are difficult to batch at certain stages of the batching sequence
|Calibration is “hands off” and automated and can be executed after every batch if required.
|Calibration is cumbersome and messy; the frequency is reduced due to the inconvenience.
|New Admixtures can be added to the scale simply
|New Admixtures require a full admixture line, and possibly an extra controller.
|Large quantities of admixture (up to 225l) can be dispensed rapidly and accurately into the batch, ensuring optimal dosing and no delays in the batch cycle.
|Dispensing large volumes can cause increased inaccuracy, an inability to dispense at optimal time in the batch cycle and delay the batch cycle time.
|The batching hoppers are continually emptied and cleaned after each batch.
|Reliability can be hindered by the efficiency and cleanliness of the pulse meter.
|The weighing of the liquid ensures an accurate dosage, continuous self calibration maintains accuracy.
|To ensure accuracy a second pulse meter or sight glasses is often needed or requested.
|Target weigh tolerance of 0.01% to 0.05% of volume.
|AS1397 allows a tolerance of ±5% or less
|Each batch is weighed which makes it easy to detect overruns or incorrect dosages.
|Difficult to detect overruns or incorrect dosages.