Spin dryer

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In the GDR widespread table sling type TS 66, the underlying air-filled rubber ring is missing
Spin dryer with water turbine drive from Switzerland

A spin dryer (also known as a laundry centrifuge ) is a domestic appliance in barrel shape that is used to pre-dry damp textiles by machine using centrifugal force . It is not used that much today.

development

Not only hand washing the textiles, but also the subsequent wringing out was a job that put a lot of stress on the arm muscles of the laundresses, but also on the fabric of the laundry , until the late 19th century . This was initially done by hand and later with a wringer or a laundry press. The wringer consists of two rubber rollers between which the laundry is pressed. The wringer was either muscular (laundry crank), later also electrically operated and partly attached to the washing machine. In the laundry press, similar to a fruit press, the wet items of laundry were compressed by lowering a piston and the water was squeezed out. Some of these presses worked hydraulically , for which the pressure of the water pipe was used. For this purpose, for example, a thick-walled iron vessel was lined with rubber and the water squeezed out the inserted laundry by filling the space between the container and the rubber.

Dehydration was much easier with the help of the first spin dryers, which were built around 1900 and could initially be operated by hand without a motor. Two people provided the necessary drive .

The first electric spin dryers hit the market in the 1930s. They had a very small volume and did not yet have a lockable lid. For this, the machine had a base made of solid iron, which, with its large mass , ensured that the sling did not start to wander. The problem was later solved by resilient mounting of the drum and counterweights made of steel or concrete . The machines could now also be locked , which represented a significant improvement in safety , because commissioning was sometimes only possible with the lid closed. Opening the lid is often automatically combined with braking the drum. Simpler spin dryers are slowed down manually with a pedal.

function

A spin dryer is used to remove water from laundry that is still wet from the washing process in such a way that it is at most still damp afterwards. This is mainly done at the end of the washing process before drying, but it is also useful during the actual washing, as the residues of the soapy water are thrown out of the laundry before rinsing in clear water.

However, spinning refers to the entire process of turning during washing. In the cylindrical high tonne , the laundry is introduced into the opening and above the inner and seventh drum is rotated at a high number of revolutions. The centrifugal forces generated during rotation press the laundry against the drum wall and thereby dewater. The water escapes from the laundry and can leave the perforated drum. At the bottom of the side of the outer shell is an outlet through which the water drains.

Electric spin dryers either have a spring suspension for the drum themselves to compensate for the movement caused by imbalance , or they have to be operated on a rubber cushion (table spin).

The electric drive usually consists of an asynchronous motor ( capacitor motor ), the number of pole pairs of which determines the speed via the mains frequency. The speed of the table extractors widespread in the GDR was around 1400 min −1 .

For the forces that occur, see the example in the article Centrifugal Force .

history

The first spin dryers, which were sold in large numbers in the 1930s, were quite expensive and therefore only affordable for wealthy households. After the Second World War, during the economic miracle, the spin dryer experienced its heyday. On the one hand, larger strata of the population were now financially able to buy a spin dryer, on the other hand, prices fell. At that time, washing by hand was still used in many households, so the spin dryer made work easier; In addition, many of the washing machines customary at the time did not yet have a spin cycle, and simple tub washing machines that did not have a drum and therefore could not function as a spin at all were still widespread. At the beginning of the 1960s, around 27% of households in what was formerly West Germany owned a spin dryer.

After the introduction of fully automatic washing machines, which could also offer a spin cycle after the washing program, spin dryers lost their importance and have almost completely disappeared from the market today.

In Eastern Germany, the proportion of fully automatic washing machines produced by the largest manufacturer ( Waschgerätewerk Schwarzenberg ) was only around 15%, so that there was more common with spin dryers until the fall of the Berlin Wall . Today, spin dryers are rarely found in private households, but they are still to be found in laundromats and in the changing areas of swimming pools , where they are used by bathers to spin out their swimwear .

Efficiency

To compare the efficacy of spin-dryers or spin function for washing machines there is the Spin Class . The highest class is A with a residual moisture of <45%. Lower residual moisture levels can hardly be achieved by spinning. The residual moisture is at 1000 min -1 at 60%, at 1400 min -1 by 50% and at 1600 min -1 at 45%. It should be noted that the centrifugal force and thus the spinning effect increase with larger drum diameters (washing machines for 10 kg of laundry instead of 5 kg of laundry) and the residual moisture therefore not only depends on the spin speed.

In order to save energy, the spin dryer may still have a right to exist today, as more and more households are running tumble dryers . The use of a spin dryer makes sense in terms of energy, at least when the spin speed of the washing machine is below 1,000 min -1 . But even still at spin speeds up to 1500 min -1 , the residual moisture of the laundry can possibly by means of a spin can be further reduced. The speed of a typical spin dryer is 1,400 min -1 or 2,800 min -1 (asynchronous speeds in Europe or at 50 Hz mains frequency). At 60 Hz the speeds are 20% higher. However, the speed is only meaningful in connection with the drum diameter. The speed is quadratically, but the diameter is only linearly included in the centrifugal force. At the same speed, a 60 cm drum therefore develops twice as high centrifugal force as a 30 cm drum. But if the speed increases from 1,400 min -1 to 2,800 min -1 with the same drum diameter , the force effect increases four times.

The energy required to remove the water from the laundry is significantly lower with spinning than with evaporation or evaporation (dryer, hanging the laundry in the heated apartment). Therefore, every additional part of the water removed by centrifugation is an energetic gain. After 10% less residual moisture per wash load corresponds to approx. 0.5 ... 1.5 kWh of the dryer or drying (with a condensing boiler , the evaporation heat used for drying laundry can be recovered when sucking in moist air , see flue gas condensation # energy efficiency ).

The use of a spin dryer can also have a positive effect on allergy sufferers who are sensitive to detergents and fabric softeners, as detergent residues are reduced by ejecting residual water from the laundry, which is not the case with tumble dryers.

See also

Web links

Individual evidence

  1. a b Stiftung Warentest on spin speeds , accessed on December 30, 2017.