Professional ironing service: a roller or a calender after all?

Ironing rollers and ironing calenders: design breaks

– What are the design differences between the ironing rollers and calenders?

- Differences in design are fundamental: in the case of calenders, the main ironing tool is a metal cylinder heated from the inside either by electricity or steam, and a set of ironing conveyor-shape tapes, bending around the cylinder area as much as possible and pressing laundry to a flat surface with a certain force. That is, while the cylinder rotates, the tapes move together with it at the same speed, straight laundry is pulled in the gap between them, the ironing process occurs and a large amount of moisture is evaporated simultaneously. This feature of calender design allows ironing laundry with 50% residual moisture, straight after spinning (either in a centrifuge or in a washer-extractor with a final spin). That is why they often call calenders the drying and ironing machines; they are more productive.

Roller process is much like the household ironing process with an iron: there is a special radius surface, called an «ironing tray», to which laundry is pressed by the roller, pulling the laundry through the ironing surface. The roll itself is covered with a soft cloth and has a special spring sublayer or winding with metal wool. Compared to calenders, rollers evaporate less moisture, they are less productive, that is why laundry, dried in a dryer to a residual moisture of 25% or less is the only one to be roller-ironed. At the same time, the quality of roller ironing is deemed better, since there is a sweep effect. However, herewith, calender ironing mode is more gentle, as there is no friction of laundry on the ironing surface, so that laundry wears out less.

– What is the high-quality roller/calender ironing ensured by? What parameters affect this?

– As I have already said, quality of roller ironing is better due to the process of sliding along the heated surface, since fabric is stretched, evenly smoothed, and creases, crimps and wrinkles are removed; it is different in calendars, where laundry is tightly pressed to the heated cylinder with tapes, and if any folds occur in the process, they remain on the laundry. Plus, un-smoothed stripes may remain on the linen, if there is large gap between the tapes as a result of their wrong tension.

–But, nevertheless, twice folded linen can be well ironed with the calender almost without folds…

– It all depends on laundry feeding, skills of the ironing woman, you need training to do this: ironing women know how to feed laundry in both rollers and calenders properly so that linen is not tightened.

– What modes and for what type of fabric can be configured on the controller?

- «Vyazma» roller and calender main controllers are originally designed to meet the requirements for various types of fabric. There is a standard, setting out the temperature for ironing of certain types of fabric. Accordingly, our controllers, even the simplest ones, have three heating levels pursuant the temperature of the ironing surface. The user can choose a particular temperature depending on fabric ironed.

Pursuant to the instruction it is necessary to allow the roller reach required conditions when switching from one temperature to another. All controllers used in VG-1430, VG-1630, VG-2030 rollers, as well as in all calenders, have smooth adjustment, that is, the user can set almost any temperature. In addition, it is possible to smoothly adjust the speed of linen ironing: against the tray in the rollers, and together with the cylinder in the calenders.

In small controllers that we use in VG-1018 and VG-1218, there are also three ironing speeds: the slow one of 1.25 m / min for low temperatures; the medium one of 1.85 m/min, and the fast one of 2.5 m / min, which can be used for higher temperatures. In any case, the user himself can choose the speed and temperature ratio, based on performance he wants to get, and the type of ironed linen. There is a more extended speed range with an upper limit in controllers, managing large rollers and calenders, which exceeds two or more times the ironing speed in small rollers thanks to the increased shaft diameter. This parameter makes the machines more productive.

– How are the emergency and security systems arranged in «Vyazma» ironing equipment?

– There are quite strict requirements of the Eurasian standards for security support of the machines. Our machines are designed for full compliance with the regulations, sometimes even in excess of the set requirements.

Design of «Vyazma» ironing machines prevents the user from access to where he should not get in, he just may intentionally do it

All rollers and calenders have operator's hands protection system, since loading of laundry into the ironing zone is always manual, in order to protect the user's hands in the dangerous zone, which is the ironing one, where there is heavy traffic, there is a special safety panel, or, as it is called, "safety bar" not to pull in his clothes. In case something gets in, microswitches are actuated, and the drive stops, and even reverse is on in the calendars so that the user can release the laundry. Moreover, if an emergency stop is required, there is a special emergency switch, installed in the accessible area in accordance with the standard requirements.ь.

Our machines are fully compliant with Eurasian safety standards, sometimes even in excess of the set requirements

Then, the controller has a limiting temperature parameter not to exceed the temperature during heating: even if the temperature is beyond the operating temperature set by the operator for some reason, heating will be turned off, and overheating will not occur. If, let's say, on the contrary, the calender does not reach the set temperature for a certain period of time, heating speed is not ensured, the controller alarms of possible tubular heating elements malfunctions. Therefore, it is necessary to take preventive measures, check and replace the tubular heating element. Also, in the event of any overloads during the drive operation, accidents, damage, or if the user, for example, did not have time to think out and feeded lumpy laundry, there is strong resistance when the tapes move, drive overload protection activates, the drive stops, and operation is over. Not to mention the existing ground fault protection in case of insulation damage, etc. There are a lot of protection elements, for all possible modes. The most important thing is that user is protected, the controller system protects against overheating.

– And what is provided in the event of a supply disconnection?

- There is a manual system for emergency power cutoff. There is a special handle in the kit (it is installed in the frame): the side facing opens quickly, there is a rotary switch there, disconnecting the gearbox drive from the conveyor drive, and a handle is inserted. To prevent tapes and linen from burning, or if the drive is suddenly jammed, you can remove all the tapes even by handle rotation, they are easily taken down: remove the rear facing, lift the tensioning roll, rotate the tapes until the lock is aligned, pull out the lock, and release the tapes. It is easier with the rollers: this handle is not needed, since there is a shaft-removing mechanism, you can withdraw the shaft at any time, it will not burn, even if the ironing tray is heated to the maximum temperature. By the way, the fact that the roller cannot burn is its advantage, as you can easily release the laundry, but there is another problem with the rollers due to carbon deposits formed in the process of ironing over time: noils get heated to a high temperature, burn and stick to the ironing surface. Therefore, rollers need more frequent cleaning than calenders.

UPGRADED SERIES OF «VEGA» IRONING CALENDERS»

– We completed modernization of calenders in 2018, added new models, not manufactured before. What is the advantage of «Vega» calenders compared to their «Lotos» precursors?

– Before «Vega» calender production, we studied a lot of calenders from other manufacturers and took into account all the shortcomings of «Lotus» calenders, namely the following: the LC series calenders were hard to maintain, even a small repair, such as support rollers replacement, required disassembly of almost the entire machine. Now the design is modular: no need for complete machine disassembly even for serious repairs and maintenance, it became accessible in this regard, you can easily remove almost any shaft if the need arises, without disassembling the entire calender.

– What is the reason for replacing bearings with bearing assemblies?

– This is done precisely in order to level out all possible assembly inaccuracies, so that shafts are adjusted evenly. Previously, the problem was with not self-adjusting supports, thus the shafts jammed and creaked distinctively in operation at heating. It is not a problem now.

– Are the calender supports self-adjusting now?

- Yes, self-adjusting supports are used in the new calenders: the shaft is mounted on four «independent», free-rotating thrust support rollers, making its rotation free, without jamming, and calender operation is less noisy.

– And what is the advantage of the chrome plating on the calenders and rollers?

- Chrome plating allowed to increase the corrosion resistance of driven elements and make the ironing surface perfectly smooth, thereby improving the quality of ironing. – Along with this, design of cylinders in «Vega» ironing calenders has changed – they are more thin-walled, which, in turn, allowed elimination of problems with uneven heating across the entire width of the ironing zone. As for the rollers, their surface was originally stainless, but stainless steel is a very inconstant material, and it was impossible to get a high-quality tray with this surface. And stainless steel has a big disadvantage: it is subject to large thermal deformations when heated.

Thanks to chrome plating, we have obtained a combination of two previously difficult-to-match properties in stainless steel: surface quality and significant heat resistance at the same time

But we still have stainless steel trays in VG-1018, 1218 rollers: they are small and not so much deformed. We are not going to complicate these machines yet. Now they are not inferior to imported analogues in their design, and more advanced technically and technologically compared to the domestic ones.

– Are there fluoroplast extractors in «Vega» calenders as well?

- Yes, we had to add fluoroplast extractors due to the chrome plating features: it is very hard, and often quite abrasive; metal extractors are erased and leave traces on the cylinder; fluoroplast ones have no traces and do not scratch the cylinder, separate the laundry from the shaft carefully without damage, which is sure to increase the quality of ironing.

– What are other changes?

– Heater design has changed, it became more productive, with premium efficiency, that is we get higher performance with the same capacity. In addition, the temperature measurement system became more accurate: thanks to this, the controller maintains the set temperature better, there is no noticeable «dip» when cold and wet laundry is fed into the ironing area. «Vega» calenders have a hold-down cylinder as well, placed at the inlet to the ironing zone, and its weight helps to smooth the fed laundry: even if laundry has some folds, it straightens these folds. The quality of ironing has increased significantly and noticeably. It is also worth noting that we use a new drive, with a different gear motor, and we made new thermal insulation in the machines, both of the cylinder itself and the heater inside, therefore, heat loss from the calender is much less now, hence there is more efficient, faster heating to the set temperature and energy savings.

We used controllers with different behaviour in the new calenders: now they choose on their own the method to maintain the temperature, aimed at maximum savings

When you need a fast intensive heating, all tubular heating elements are on at the same time, and then, depending on ironing intensity of the user, the controller itself selects groups of tubular heating elements to turn on/off, and even applies a pulse heating mode, thereby reducing power consumption significantly.