More than cosmetic changes

2 April 2001



Mike Clark separates the desirable drycleaning machine features from the marketing gimmicks.


Drycleaning machine manufacturers are constantly introducing new features in a bid to gain an edge over their rivals.

Every few months one company or another introduces “revolutionary” improvements to enhance safety and efficiency. A cynic may wonder whether any real progress is being made, or if it’s just marketing.

The single most important development in the last two decades has been the introduction of the microprocessor into drycleaning machine controls. This has enabled total control over the cleaning, drying and distillation cycles.

Program options

Most machines are now sold with a series of built-in programs chosen by the manufacturer to give optimum cleaning for all normal classifications. The cleaner will generally have the option to supplement these with specific programs to cover special variants the business needs, for example, leather oil additions, or distilled rinses. Cleaners should check just how straightforward or otherwise it is to add their own programs.

If English is not your first language, it may also be helpful to choose a machine with a microprocessor that can display text warnings and process status in your own language.

A number of companies can supply machines with a remote fault diagnostic capability. However, you need to consider carefully the actual benefit you will derive from this facility. If an engineer can talk an inexperienced operator out of a problem without the need for a visit, you will reduce machine downtime.

If the engineer is able to determine the fault and arrive with the correct part, again this will limit the time the machine is out of action.

Manufacturers who supply the major chains are very responsive to suggested developments. When I was buying 30/40 machines a year for Sketchley, we had regular briefings with our suppliers and the majority of ideas we fed through became a reality. I have no doubt that Johnson, 5-a-Sec and manufacturers’ agents throughout the world do the same.

In these instances, the resulting improvements will be genuine advances in safety, ease of installation/maintenance or improved productivity.

The reduction of the machine footprint is one example of a genuinely helpful advance. The ability to get a cleaning machine through the front door of a shop, without removing the shop front or window, stemmed from supplier/key account relationships.

Accessibility to key components is an important consideration. Poorly-sited recovery heads, refrigeration units and filters increase the difficulty of servicing and raise costs.

Firstly, servicing charges will be higher because an engineer will need more time to carry out the work. Secondly, longer periods of downtime may cause backlogs of work, incurring overtime to clear.

Lastly, the inability to offer a fast service may cause lost sales. Stand back from the machine, look at its construction and beware if parts seem to have been added randomly. Reputable suppliers will ensure that all the main components are made of a suitable grade of stainless-steel. Frankly, to do otherwise would be very short sighted and the resultant corrosion problems would ruin their reputation. Claims about the quality of the steel are therefore mainly window dressing.

Automating routine maintenance tasks brings real benefits. Such advances not only help make the machine resistant to lazy operators, they also improve productivity. Systems that drop the filter automatically throughout the process remove the need for dedicated programs with the resultant lost production.

Self-cleaning button traps with a central vertical strainer column that obstructs the flow as the solvent gushes out of the cage, force the soiling behind the column and keep the facing side clear.

Self cleaning

Self-cleaning lint screens that developed from back-plate flushing, itself a useful innovation, use a jet of incoming solvent to spray the screen. Once the solvent level has been established the flow reverts to normal mode.

Auto pump-out still-cleaning systems that limit the need for manual scraping to six weekly intervals, are a significant safety advancement as they help to reduce employee exposure to solvents. As the waste is generally collected for recovery or incineration by a reputable and licensed waste-disposal company, the environment also benefits.

Self-drying button traps that limit operator exposure to solvent vapours and reduce the handling of solvent impregnated lint also fall into this category.

A relatively new and important environmental advance is the provision of a system to detect perc-in-water. where applicable. By constantly measuring the comparative electrical conductivity of the cooling water, the device prevents a build up of perc in closed-loop cooling tower systems or avoids putting large quantities of the solvent to drain.

Visual warning

If perc is detected, the machine is switched into a safe/stop mode and the machine displays a visual warning, Perc-in-water.

Manufacturers are now producing machines that can use either hydrocarbon or silicone solvent. Some manufacturers will fit two separators in such machines, to overcome the difficulty of the similarity of the specific gravity of silicone solvent and water.

One separator is used only for recovered solvent and for the first 20 litres of distilled solvent. (These are the two areas that contain most moisture.) The second separator (referred to as the main) takes care of the rest of the solvent and overflows, as normal, to the distilled tank.

The first separator does not overflow into any tank. If the next load is a normal two-bath process where the break-wash may benefit from moisture, the contents are fed into the first wash. With any other load, the content from the first separator goes directly to the still.

Some manufacturers offer this as a retrofit service.

Innovations

The introduction of these dual solvent machines is timely and extends the industry’s choice and flexibility, but the marketing needs to be handled responsibly, without resorting to knocking copy.

Interestingly a number of innovations originally developed for hydrocarbon machines are now being used to improve the design of perc machines.

Modifications to ducting, increases in fan size and elimination of air-flow obstructions, which were introduced to bring down the extended drying times, are a good example. While reduced drying time does not necessarily save energy, it is a significant benefit as machine time is generally the key factor limiting productivity. Soft-mounted drums allow higher spin-speeds, so extracting a greater volume of solvent and reducing the length of the drying cycle still further.

An improvement now being used in perc machines, is the use of fractional distillation to control the foaming action of the still. Abnormal temperature increases are detected and the machine is put into a safe/stop mode.

Recycling heat from the distillation process, via a double heat pump, to provide 80% of the heat for drying.

This has proved a major leap forward, both in saving energy and reducing drying times.

Machines can now achieve high solvent mileages. The need for professional servicing has been reduced to five or six hours a year. Both these advances, plus the energy and environmental improvements already described indicate the machine manufacturing industry is both responsive and innovative and this bodes well for the future.




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