Material solutions

Keeping the ironer line at its peak performancel

1 July 2011



The ironer line needs to be carefully maintained to achieve optimum productivity. Ian Harris discusses the checks and procedures involved


In most laundries the ironer line represents the highest level of financial investment and is also one of the most expensive sections to operate.

The investment in equipment often includes feeders, folders and stackers as well as the ironer.

Operational costs must take account of labour and also the productivity achieved.

Innovations in ironer design over the years, coupled with the improvements in ironer clothing, evaporation rates, ironer speed and performance, mean that production outputs of 1,200 sheets per hour are now quite common; 30 – 40 years ago the optimum ranged from 500 – 750 sheets/hour.

One important contributor to the higher output levels has been a shift in the fibre content of the sheets. Where once 100% cotton, 200gsm fabrics were used now the trend is for 50/50 polycotton 120 – 180gsm blends, followed by cotton-rich 70/30 blends and more recently 80/20 constructions.

Each blend needs different ironer settings for success.

Demands for increased production and the use of more sophisticated textiles mean that laundries have to be even more diligent in their ironer maintenance to achieve their productivity and quality targets.

The first consideration is the ironer temperature.

Historically, ironers operated at 8bar steam pressure so internal bed temperatures have generally been in the range of 173 – 176C.

The ironer temperature dictates the quality or type of clothing to be fitted to the rolls, its durability and life-cycle and the best type of wax to use.

Now laundries are increasingly operating the ironer at steam pressures of 10bar or more, which can produce bed surface temperatures up to 184C.

This temperature can be easily exceeded on ironers heated by direct gas firing or by thermal oil, where bed temperatures up to 200C and above are becoming more common. These raised temperatures bring their own problems that need to be carefully managed.

They affect the choice of ironer clothing which must be able to withstand such temperatures. Aramid or aramid-faced polyester clothing are becoming essential. Waxes with higher melting points are needed to avoid carbon deposits on the ironer bed.

Higher temperatures also demand increased roll speeds to increase production and to avoid damaging the textiles. A cotton sheet will very quickly scorch if in contact with the ironer bed for too long. Polyester can melt in such conditions and higher temperatures will destroy most optical brightening agents (OBAs) and turn them yellow.

These increased speeds produce greater friction between the textile and the bed.

This results in much higher tension being placed on the roll clothing so when dressing or re-clothing the rolls it is absolutely essential to fasten the cloth securely across the whole width and to make sure that the overlaps and thickness are correct at all times.

If the roll clothing is not correctly secured it will very quickly

corkscrew off to one side or cause double or even treble thicknesses, which will soon damage the drive.

This fault will also distort the much thinner flexible ironer beds on some modern designs.

Anyone that has had to replace a warped ironer bed will know how time consuming and expensive this type of repair work can be.

Key steps in ironer care

Ensure that the clothing type and wax can withstand the ironer’s operating temperature.

When re-clothing the rolls, check that the starting edge is both straight and correctly and firmly secured across the full width of the roll.

Check that the correct weight of clothing is used and the correct number of turns are applied. Any excess must be trimmed-off to produce a straight line across the width of the roll for the trailing end of the clothing. Note that the trailing end should be exactly in-line with the leading edge that is secured to the rolls, without any bulging overlap.

Don’t try to hurry the task of re-clothing the roll. Take time to carefully examine the spring padding to ensure it is in good condition and to a consistent standard across the full width of the roll and around the entire circumference.

If the roll perforations are visible check that there is still a good airflow. Poorly trained ironer operators will frequently leave the roll vacuum functioning whilst waxing the ironer and this will quickly lead to the clothing becoming clogged and the vents on the ironer rolls getting blocked.

Both faults will significantly reduce production.

Ideally the rolls should be re-clothed while the ironer is still hot. After re-clothing, always girth the roll with the girthing tape supplied by the ironer manufacturer to ensure the roll is the correct size. Normally after re-clothing it should be very slightly “over-sized” to allow the new clothing to “bed-in” to create the perfect snug fit to the ironer bed. Any excess should be trimmed off – always follow the manufacturer’s instructions and guidelines.

Once the ironer has been running for 6 – 8 hours after re-clothing, it should be re-girthed and, again, any excess over-lap of the roll clothing should be trimmed off.

This re-girthing process should be repeated at daily intervals until the clothing is fully bedded-in and there is no excess to be trimmed.

Routine checks

This is a good time to carry out a few more essential but routine checks on other aspects of the ironer line.

Replace any missing feed-bands both on the ironer and on the feeder and folder.

Re-tape the ironer or replace missing guide tapes.

Check and verify that the bed-roll interface pressure is correct – or at least within the tolerance levels given in the manufacturer’s operational manual. It is normal to reduce the bed-roll interface pressure by up to 20% immediately on re-clothing the rolls. As the clothing beds in over the next few days the pressure can be increased to the optimum.

Check and adjust the vacuum on the rolls. Vacuum meters are readily available from a number of suppliers and placing the vacuum gauge at intervals across the width will quickly identify any areas of poor suction and potential problems.

Measure and record the roll-to-roll differential speeds to ensure that the correct tension is placed on items as they are fed through the ironer.

Check that bed temperatures are even and consistent – at the target temperature – across the complete width of each chest – especially on the horns (both back and front).

If the iron is steam-heated, check that all steam traps function correctly to prevent the chests from becoming water-logged or air-blanketed.

Check that the air vents on the horns of each chest are working correctly to remove cold spots caused by air accumulation (air-blanketing).

Minimising risks

Making these routine checks will minimise the risk of problems and of reduced productivity.

Most laundries will set the ironer according to the condition (wetness) of linen that is delivered from the washroom, taking account of the required “dryness” of the work as it leaves the final roll.

If the ironer suddenly starts to discharge damp work, when it had been delivering dry work don’t allow the operators to slow down the ironer without first investigating the possible causes.

Check back

It should be relatively easy for an experienced operator to check back through the system to identify the problem.

Is the steam pressure down?

If work is being pre-conditioned, has the tumbler timing been changed or has a fault developed on a tumbler? Has the tumbler operator forgotten to clean the lint screens, so reducing the airflow and the tumbler’s evaporation rate?

Are the full extract or membrane press times and pressures being maintained or is a blocked drain line preventing the extracted moisture from escaping to the sewer?

It’s also worthwhile periodically checking the ironer‘s evaporation rate. Most manufacturers will include some information relating to the machine’s optimum moisture evaporation in the technical data.

Some manufacturers will even suggest ways that this can be tested and monitored by the user – with a list of supporting “checks” to investigate if the evaporation rates achieved are below target.

Evaporation rate

The evaporation rate on all laundry equipment is a measure of the amount of moisture (in litres or kg) that the equipment can evaporate in a given number of minutesor per hour.

So, theoretically, if the laundry is operating with a 45% moisture retention (MR) – then this means that every 100kg dry weight of work leaving the washroom will weigh 145kg – consisting of 100kg of fabric plus 45kg of water.

So, notionally, if the ironer has an evaporation potential of 10kg/minute then it will take 4½ minutes to evaporate the moisture from a 100kg batch of washed textiles.

If the average weight and size of a sheet is known, working out the target speed for the ironer is relatively simple.

Assume that, on average, a sheet weighs 950g and measures 120cm x 240cm (width x length).

Then, a 100kg load of work will contain 105 sheets.

If the sheets are fed edge-to-edge selvedge first, then the total will be 105 x 120cm = 126m.

The ironer needs 4½ minutes to evaporate the amount of moisture in the load and therefore the target speed for the ironer will be 126m ÷ 4½ = 28 metres per minute.

This calculation does assume edge-to-edge feeding to gain the full evaporation potential of the unit.

In reality the evaporation rate for the ironer will be affected by the temperature of the work being fed into the ironer.

The warmer the sheet the less energy is required to evaporate the moisture and therefore the higher the output.

However, from this base potential output number it is now possible to examine actual productivity versus potential and the various options that the laundry can control and change to improve output.


Typical Vacuum gauge Typical Vacuum gauge


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