– a wheeled and lidded plastic trolley and a lightweight canvas washable laundry bag capable of being handled by just one person when full. It is unlikely that single use plastic will be permitted (because the uncontrolled build-up of microplastics in the world’s oceans and in every human body will have to be addressed). This means that every rental container could need to be suitable for use in hotel corridors and restaurant kitchens, for example. The vans and loading platforms will be designed for safe operation by just one person to accommodate future labour costs. The containers could be suitable for automatic discharge at the entrance to the sorting area in the rental laundry. The soiled textiles could be unloaded automatically onto a carefully designed series of sorting belts, whilst the containers will go through decontamination (probably a batch of washing for the bags and an automatic trolley washer).
Sorting
One common current way of separating out clumps of soiled textiles is to transfer them from the initial conveyor onto a second belt moving at a faster speed. This can be repeated a second and even a third time to separate even the largest clump. Once the items are moving separately, they can be scanned for metal and anything containing metal can be diverted to a special line to be made safe by the one operative in charge of the sorting area.
Every item can then be passed under a visual scanner and diverted according to its appropriate classification. The scanner would probably use a simple form of artificial intelligence (AI), working in the same way as the human brain, using visual recognition. Alternatively, if the items are labelled with radio frequency identification (RFID) tags they could be recognised by the signals from these. A series of air jets would then blow each item off the conveyor, at appropriate points, into the collection container for the classification. Much of this is already available and being taken up.
For critical applications, where a double check on the sorted batches is needed, this can be automatically added using a second camera after each sort to verify that the item is going into the correct load, diverting any errors back around and into the system again. Detectors for metal objects and other potential hazards can
easily be built into systems of this type. None of the components of the system described is particularly expensive and the easy option of double checks on each sorted article means that systems with very low error counts should be economically quite feasible.
Washing
The move towards CBTWs capable of handling every batch of washing can be expected to continue. Up to the present, the trend has been to higher batch weights to give greater hourly throughputs from every washing line, but now greater attention is needed to produce machines with the labour-saving automation of a CBTW, but which can handle economically the much smaller batches required by smaller commercial laundries and on-premises laundries. Considerable progress has already been made with smaller CBTWs, but much better small designs are needed for the full potential of low-capacity machines to be realised.
Current CBTW designs often represent beautiful engineering, but they are imperfect when it comes to automatically optimising water flows and chemical dosing, for example. The recent development of pulse flow technology represents a significant step forward but is not always understood by some designers. The key is the recognition that each compartment of the washer is a chemical reactor, and the efficiency of the reaction can be improved using the counterflow rate of water through the stage. If this is varied in the optimum manner, then the washing and rinsing proceeds more quickly, enabling either reduced water demand, better quality, reduced chemistry or greater throughput (with shorter stage times). The target varies with the customer, making this another area for an appropriately programmed AI-driven controller.
Dewatering
Perhaps the most rewarding area for further work with AI control is at the membrane press on the CBTW line. The efficiency of the dewatering has a dramatic effect on the operating cost and the productivity of the tumble dryers, for example. Because these consume large amounts of expensive heat energy in a thermally inefficient process, any improvement at the press can have a dramatic effect on the overall cost, especially for fully dried towelling. The
same is true of the effect on the ironer. The press needs a rapid ramp up to pressure, without causing any burst tears, followed by enough time at pressure to remove moisture by the cheapest method – squeezing it out. In rough terms, pressing consumes only one fifteenth of the energy of the tumble dryer, per litre of water removed. Yet it takes considerable time and skill to set up and maintain a membrane press with the right settings to deliver no burst tears and enough time at pressure. The engineering team has to tune the ‘wait times’ in the programme sequences down to the minimum and identify every means possible to minimise the ramp time and maximise the time at pressure. It should now be possible to deliver this optimisation using an intelligent electronic controller, where again AI should come into its own.
Tumble drying
Despite startling advances in thermal efficiency of tumble drying, this is still the Cinderella stage of the laundry, consuming large quantities of heat energy whilst often producing variable degrees of dryness and many shades of grey; and failing to maximise productivity and energy efficiency. The concept of automatic terminators was a great step forward, but
SEQUENCE WASH: Using AI to sequence wash loads to the CBTW is just one way of maximising productivity through the washing line. It could also be used to minimise energy consumption at the dryers
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