Factors that can influence machine choice6 October 2015
Roger Cawood examines the technical issues that should be considered when investing in a new machine, and in particular the factors that affect the choice of solvent
Businesses that are investing in a drycleaning machine, whether as a replacement for old equipment, an additional machine or a sole machine for a start-up business will need to plan the purchase carefully, examining several factors before making the final choice.
Inevitably the starting point will be the choice of solvent. A wide range of solvents is now available and the choice may seem bewildering. The aim here is to provide straightforward information to assist cleaners in making an informed decision as the solvent choice will have far reaching effects on the business.
Check the label
The first factor to consider is care labelling. Circle A, which covers all commercially used drycleaning, is rarely seen now and the understanding is that only perc (indicated by circle P)?and hydrocarbon (circle F) are officially covered.
It is important to be aware of this because if a garment or textile fails in cleaning and it has been cleaned in a solvent that is not specified on the label, the manufacturer or retailer may refuse any responsibility.
For this reason, these comments mainly refer to perc and hydrocarbon as these are the solvents that are most commonly used in the UK. Both have a proven track record and are supported by a range of well-researched and reliable detergents and spotting products.
Solvents and their properties
Perchloroethylene and hydrocarbon have been in use in drycleaning for many years. They are very different in origin and their properties differ.
Perc is a synthetic non-flammable solvent with good solvency, while hydrocarbon solvents, a byproduct of crude oil, are flammable and have a much lower solvency power.
Perc was developed as a solvent in 1920 and has been in common use since 1955. In this year, tricholoroethylene, a previous synthetic, started to fall out of ,favour as it affected the dyes of cellulose triacetate textiles, which were then becoming fashionable.
Hydrocarbon was introduced as a solvent in 1994. Its use gained some momentum as a replacement for 113, which had been popular with those handling high volumes of delicates, leather and suedes.
The growing eco movement identified 113 as a chemical that would damage the ozone layer and it was finally banned in December 1999.
Both perc and hydrocarbon can produce good standards of drycleaning.
In recent years other alternative solvents, such as K4, have been developed but these have yet to make an impact on the UK drycleaning industry in general.
Some hydrocarbon machines are classed as "multisolvent" and this might make a switch to another alternative possible in the future. Bear in mind that though a switch could have costs in terms of wasted solvents, internal cleaning and modifications.
Cleaners that are thinking of buying a hydrocarbon machine, should take a closer look at machines that use spray systems and hot solvent.
These machines have been on the market for around six years, some do not use high speed to extract the solvent from the load and they do not have a still. Spray system machines have the advantage of lower running costs and machines that avoid high-speed extraction could have much lower installation costs as they will not need to be built into the floor.
Staff must be competent
Highly competent staff are essential if you are to get the best from any machine, irrespective of solvent.
Staff that are well trained and conscientious will be able to operate successfully with either hydrocarbon or perc.
This issue is important because perc is a very searching solvent and it can adversely affect garments with pvc trims, polystyrene beads or the plastic logos found on some designer garments.
Staff must be able to identify the risks posed by such garments. Cleaning them in perc could damage not only the garment with the trim but also others in the load and possibly result in expensive claims.
Practical training including an element of theory is vital in developing a successful drycleaning business. Professional training is available through The Guild of Cleaners & Launderers and the equipment supplier should be able to arrange appropriate machine specific training.
New businesses should note that owners as well as staff would benefit from such formal training.
While some operators become skilled largely through experience, this is not always the case and even long-serving staff may benefit from refresher training.
Health and safety is important
Businesses must have a thorough knowledge of the Health and Safety issues related to the operation of both the equipment and the solvent.
Ignoring the industry's health and safety guidelines can lead to serious consequences. The guidelines will also help the cleaner to operate professionally in the event of an emergency.
If using hydrocarbon it is essential that all traces are removed in the drying stage. There have been several cases where customers have suffered severe skin irritation as a result of incomplete solvent removal.
Work classes affect solvent choice
The type of work the business handles will affect the solvent choice.
Hydrocarbon will be a strong contender for shops that handle large quantities, of silks and other delicate fabrics and designer garments.
However perc's high solvency power and high specific gravity may make it a more suitable choice for mixed loads, especially if work is often heavily soiled.
Drycleaning solvents are assigned a Kb value that indicates the solvent's ability to dissolve soiling such as oils, greases, tars and waxes. The higher the value, the stronger the solvent. Perc has a Kb value of 90 and hydrocarbon solvents approximately 28.
Specific gravity or SG is a measure of the density or weight of a liquid. Water is used a reference point and is said to have a specific gravity of 1.0 (1litre of water weighs 1kg).
Perc at 1.621SG is heavier than water. Hydrocarbon is much lighter (less than half the weight of perc) with an SG of only 0.765.
It is important to be aware of this because a solvent's weight has a huge effect on the levels of mechanical action within the drycleaning machine and mechanical action contributes significantly to soiling and stain removal.
On the other hand, it also increases the risk of damaging delicate items. Anyone that has hand-washed a chunky knit sweater it will have some idea of how heavy garments can become when being drycleaned.
As a result, delicate fabrics, should be cleaned with like work on a suitable program.
Net bagging them and processing with a normal load will not provide sufficient protection.
Mechanical action in drycleaning is influenced not only by the solvent's specific gravity, but also by the diameter of the machine cage, (which determines the height of the drop), the height of the dip, the weight and type of garments in the load, the low speed rotation of the cage and finally the length of the cleaning/wash cycle.
While specific gravity relates directly to the solvent choice and cannot be changed, the other factors can be controlled by the cleaner.
A high dip reduces mechanical action and a lower dip increases it.
The machine's low-speed rotation can be programmed to include a pause and the cycle time can also be adjusted.
In this way both perc and hydrocarbon machines can be fine tuned so that the mechanical action suits the load.
Well maintained and programmed
The experience of spending two weeks in a very busy drycleaning factory that ran a 28kg hydrocarbon machine and two 18kg perc machines was interesting.
The machines were very well maintained and had been expertly programmed. It was soon evident that there was little to choose between the two solvents both in terms of cleaning and stain removal.
This was probably down to good programming and the fact that the larger cage on the hydrocarbon machine gave increased mechanical action.
However, for best results with hydrocarbon, heavily soiled/stained items may need to be tumbled in the solvent dip or flow for up to 20 minutes whereas 12 minutes in perc is normally quite sufficient.
The overall volume of work to be handled will obviously affect the size of machine or machines required.
From this point of view, a large hydrocarbon machine can be a strong contender against perc.
However, overall process times for hydrocarbon machines (with the exception of the new spray cleaning systems) are likely to be longer than that for a perc machine. So typically a load that would take around 45minutes for perc and would need 65minutes in a standard hydrocarbon machine.
However, hydrocarbon does allow more flexibility as it can handle garments that are labelled with a circle F as well as those labelled Circle P.
See before deciding
Many suppliers will suggest making a visit to one or more of their customers to view a prospective machine and solvent in a production environment. If this is not offered, then ask if a visit can be arranged.
Preferably the customer should have been using the equipment for at least a year.
A visit is particularly recommended if considering a newer alternative, such as K4. Spend at least a day on site and try to talk privately to both the owner and the staff so minimising the chance of misunderstanding. During the visit observe the work mix, the degree of soiling and staining, the pre-spotting, stain removal and finishing.
Before signing the purchase agreement check warranty details. Ask the supplier for written confirmation of engineering back-up and the time frames for delivery, installation and commissioning of the equipment.
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