Electric water boiler

Kettle ( electric ) kitchen appliances, that are used to heat water very quickly. Depending on the model, there are boilers, jugs or pitcher -shaped designs. They have either a heating element according to the principle of the immersion heater or a heated bottom plate of the cooking vessel.

Kettle often have replaced the formerly used for heating water whistling kettle and immersion heater.

The first electric kettle was shown in 1893 at the World Exhibition in Chicago. There were long before that table cooker for people without access to a kitchen with a stove.

Modern kettle consist of two parts: a cooking vessel made ​​of plastic, metal or glass with a heater and a separate original base with cables for the power supply. This makes the cooking vessel can be easily separated from the circuit and moved freely.

• 4.1 Electric kettle
• 4.2 water boiler

Design and function

The filling with water is carried out with most devices via a manually folded up on a button or in some cases completely removable lid. For some devices, a filling is possible and provided directly above the sink. This requires a correspondingly wider spout and a wegklappender automatically by the water pressure / gravity permanent filter that allows water to flow in both directions, and the general absence of an appropriate filter in front of the sink.

The cooking vessel has in modern units, except the heating element designed as a snap-action switch temperature switch, the unit turns off automatically based on a bimetal. It is housed together with a mechanical power switch coupled to it in the housing of the cooking vessel. The temperature switch turns off when his bi is heated by the steam at about 100 ° C. For correct function of shut the lid must necessarily be closed because of the resulting vapor otherwise escapes and does not reach the temperature switch. In some devices causes an opening of the lid for the immediate shutdown.

The electrical connection to the base is carried out with many devices in the form of an all-round rotatable ( concentric ) connector. This includes a sensing pin that triggers the automatic shut-off when the cookware is removed before reaching the boiling, so that also in this case the alarm goes off by the power button, as the connector between the equipment and base otherwise damaged by breaking sparks or oxidizing, at least would ( contact resistance ). Further, this also prevents the turning off to the base leads to a further heating of the unintended now possibly empty cooking vessel.

Kettle used today have an operationally independent of the automatic cut- temperature protection. This works with modern appliances also on the shutdown and auto-return in most cases. Kettle should still not be left unattended, or run completely empty.

In the unit base or cable connector of the connecting cable are especially in high- power devices triggering additional permanent fuses that trigger when overloaded.

Designs

A distinction is made between kettle with concealed stainless steel heating element and exposed, the latter are carried out partly no longer in the form of conventional heating wires, but as printed circuits.

Performance and Efficiency

Common household kettle have a capacity of one to two liters ( electric water boiler for commercial use up to four liters) and a heating capacity 600-3100 watts. A higher power is thereby also associated with correspondingly shorter cooking times and less heat transfer to the surroundings, so far are high-performance devices over slower kettles in the energy balance at an advantage. The most powerful devices to a liter of water heated to the boiling point in just over a minute. Quick kettle have long been absent from the UK market, however, appear in the last ten years also increasingly on the German market. Because of the very high power consumption such devices are not suitable for any home installation and should be used wherever possible its own fused circuit.

Rare special designs that work on the flow principle, even only need a few seconds pre-heating to dispense hot water as hot water dispenser in smaller quantities for direct filling of cups, etc., but then takes the filling as such the longer.

Some can -shaped device with enclosed heated floor have special filling devices, double reservoirs or accurate resolution level indicators, in particular, even very small amounts of water (such as a cup or less) precisely fill and to heat targeted to this way of energy, water and time to save.

Kettle heat water as efficiently as immersion heater, but modern models switch off automatically and are therefore even more economical and most importantly safer than immersion heater. Devices with thin encapsulated heating base, especially those printed on the basis of circuits are considered more efficient than those with heating elements. Due to the better thermal insulation also have units with glass or plastic vessel having a slight advantage over metal combined devices.

Immersion heater and water heater heat water more efficiently than electric hotplates. The reason is that the energy is delivered almost directly to the water and not first have to warm stove and pot. The heating of water with electrical power is much more expensive (about 1.89 cents per liter) than, for example, on a gas stove ( about 1.48 cents per liter ), but at the usual small amounts of coffee and tea does not play a major role.

Aspects of health and safety

Most kettles are safe under health aspects. Some specimens can file nickel or hormonally active substances (bisphenol A) to the water, especially if the water remains an extended time. This is especially true for devices with exposed heating coils or those with plastic housing. There are devices that make the water boil for a few minutes; by tap water can be dechlorinated for a better taste.

Some devices have in addition to pure cooking function also possible to heat the water at a selectable temperature between 40 ° C and 100 ° C ( for example for the preparation of tea at 90 ° C and other hot drinks ), and optionally over a long hold period on temperature. For the preparation of baby food, some kettle also have a Abkochautomatik, the first heated the water to boiling point and spent some time at a preset lower temperature after cooling back.

In particular, devices, metal tank pose a risk of burns when heated in some cases above 90 ° C surface is touched when handling. Better thermal insulation properties are bidding units with glass or plastic surface, as well as devices with insulating jacket. A scald with boiling water can lead to large-scale second-degree burns. As a first aid immediate, direct and persistent cooling is recommended by running cold water for at least 10-15 minutes. After the burn should be sterile covered. If area scald an emergency call should be discontinued.

To prevent accidents, make sure that the kettle for children is inaccessible. The power cord does not hang. The kettle must only be operated with the stated maximum amount of water to avoid boiling over. The lid must be closed during heating, otherwise the temperature lock will not operate reliably. Kettle should only be moved upright. When pouring the water, the pot should not be tilted too much, in order to prevent an overflow of the lid and hence splashing.

Other types

Electric kettle

A virtually unknown in Europe special shape of the kettle is a native of Japan, " electric jug " (電気 ポットdenki potto ) dar. It is a kettle that is constantly on a predetermined temperature holds heated water. The heating capacity is usually lower than in Europe with such models, but it does require a holding capacity of approximately 50 watts. The consumption per day is much more like a European water heater, which is used for half an hour a day. In this kind of kettles the device for pouring must not be raised, but a pump is activated by a button, which conveyed out the hot water through an outlet.

Work in a similar electric samovars, which are common in Russia and in Turkey. You, however, have instead a cock for water extraction.

Water boiler

Another design is called hot water heaters. This is fixed container with about 5 liters, which are able to heat the water to boiling point. The device is usually installed directly over the sink and connected to the water line. First, the required amount of water from the tap is inserted into the vessel through an inlet tap, then turns on the unit. After a few minutes the water has reached the desired temperature, and can be tapped on the drain tap into a vessel underneath to Sink. Hot water heaters, due to their fixed installation more expensive and not as flexible as mobile kettle, but they hold - especially for children - a lower risk of accidents because they can not be torn down or upset. In view of the central hot water supply common today they are rarely installed. It makes sense they are but still be needed in small kitchens and the like, where regular large amounts of boiling water.