6.3 COMPUTER CONTROLLED BATCH PROCESSES
The nature of Batch processes,
- Batch processes deal with discrete quantities of raw materials or products.
- batch processes allow the tracking of these discrete quantities of materials or products
- batch processes allow more than one type of product to be processed simultaneously, as long as the products are separated by the equipment layout.
- Batch processes entail movement of discrete product from processing area to processing area
- Batch processes have recipes (or processing instructions) associated with each load of raw material to be processed into product.
- Batch processes have more complex logic associated with processing than is found in continuous processes
- Batch processes often include normal steps that can fail, and thus also include special steps to be taken in the event of a failure.
The nature of steps in a batch process,
- Each step can be simple or complex in nature, consisting of one or more operations
- Generally, once a step is started it must be completed to be successful.
- It is not uncommon to require some operator approval before leaving one step and starting the next.
- There is frequently provision for non-normal exits to be taken because of operator intervention, equipment failure or the detection of hazardous conditions.
- Depending on the recipe for the product being processed, a step may be bypassed for some products.
- The processing operations for each step are generally under recipe control, but may be modified by operator override action.
A typical process step
