One fan drives all of the air through the dryer, but the fan is actually the last step in the process. The first thing that the air hits is the heating element. After the air enters the body of dryer, it is sucked through the heating element, and then into the clothing tumbler. This is a standard nichrome-wire heating element, just like the heating element in a toaster see How Toasters Work for details on nichrome wire.
This heating element consumes lots of power -- 4, to 6, watts on most dryers. The air is drawn through the heating element and into the holes in the back of the tumbler. The metal stamping on the right, with the big holes in it, makes sure that air can enter the tumbler only after it has gone through the heating element. The hot air now makes its way through the clothes in the tumbler , and then into the holes in the door.
The air passes through the holes in the door , and out through the big slot in the bottom of the door which leads to the lint screen. The air is drawn through the lint screen and down a duct in the front of the dryer , where it enters the fan. The fan is a centrifugal type of device -- as it spins, it flings the air to the outside, sucking air from the center and forcing it out the duct at the back of the dryer.
In the next section we'll see what makes the tumbler spin. If you open up a dryer, one surprising thing is the lack of any gears on the tumbler. It turns out that the tumbler is one giant gear or actually a pulley , and the motor drives a tiny pulley. Because of the ratio between the huge tumbler diameter and the tiny motor pulley diameter, no other gears are needed!
A motor drives the small silver pulley that is visible beneath the black pulley in the picture above. The belt loops through the silver pulley, through the black pulley and then around the tumbler. The black pulley provides tension -- when the belt is hooked up, the pulley is drawn off center, and the spring tries to pull it back.
This gives the belt its tension. The same electric motor drives both the fan and the tumbler. The pulley for the tumbler belt is hooked up to one output of the motor, and the fan is hooked to the other.
Another funny thing about most dryers is that the tumbler has no bearings to help it spin smoothly. So what supports the weight of the clothes? At the back of the tumbler is a flange , connected to a simple bushing that allows the flange to spin. The back of the tumbler bolts to this flange.
In large machines such as those in launderettes the drum always rotates in the same direction. Cold air is drawn into the machine through an air intake.
Often it's at the front of the machine to stop it getting dirty and dusty as it would around the back. A fan sucks the air in and pulls it toward a heating element. It's powered by an electric motor. As cool air passes over the heating element, it's warmed and turned to hot, dry air. A thermostat turns the heating element on and off periodically to stop the machine from overheating or cooking your clothes.
When you select either the low or high temperature setting on your dryer, you're effectively altering the thermostat setting. Did you know your dryer had an actual thermostat?? A larger drum for smaller quantities of clothes is not an optimal choice because the drying results will suffer somewhat, and the costs will be higher.
In principle, a tumble dryer with 7 kg capacity is enough for two people , while a four-member family needs a dryer with around 9 kg capacity. This also depends on how many clothes your household changes every day. In washer dryers, the capacities of washing and drying are different. If, for example, the capacity of washing is 9 kg, the capacity of drying is around 6 kg.
This also means that one full washing load has to be dried in two parts, which takes more time. All household appliances bear energy labels. Similar to other household appliances, we rate tumble dryers into seven classes, from A to G, depending on their energy efficiency. Class A is the most energy efficient , while class G is the least efficient.
Appliances that receive a letter grade from A to C are considered energy-efficient, whereas appliances that consume considerable amounts of energy are labelled with classes from D to G. We should always opt for an appliance with a letter rating as close to A as possible. Letter grades can also be followed by plus signs. The efficiency of drying is also measured in letter grades, i. The better the condensation efficiency of the dryer, the less moisture it expels into the surrounding area.
This is important because we certainly do not want to increase the risk of mould growth on the walls of our apartment. A very energy-efficient tumble dryer can also be placed in a windowless room or passive house without having to worry about excess moisture. Condensation efficiency is labelled with letter grades from A to G. Energy labels also include information on electricity consumption and drying efficiency.
Both are presented with coloured bands and letter grades from A to G. It is best to buy a tumble dryer bearing a label as close to class A as possible, indicating the most efficient household appliances. The standard size of tumble dryers is similar to the size of washing machines. Their width is usually 60 cm, depth ranges 60 - 65 cm and height 85 cm.
Gas dryers have a gas burner that does the heating; electric dryers have electric heating elements. Both types utilize electricity for the controls and the motor that turns the drum. A large belt encircles the drum and rolls through a pulley on the electric motor. Gas dryers are combustion appliances.
0コメント