But where does the Air Enter the Dryer?

A clothes dryer will be found in just about every house in the United States, and thousands and thousands extra of them are manufactured every year. You will be shocked at how easy this widespread machine is. They’re very dependable, and very cheap to construct. Clothes dryers have:

A rotating tumbler that holds the clothes.

An electric or gas powered heater that heats the air that’s drawn through the clothes as they tumble, which in flip heats up the clothes and the water in them.

An exhaust vent that passes out of the dryer and out of the home — this is how the water exits the dryer within the type of steam.

In this version of How Stuff Works, we’ll take apart a clothes dryer and discover how each system works. However the place does the air enter the dryer? We’ll begin by following the air by the machine, then see how the tumbler and fan turn, and finally we’ll look at the controls.

Let’s observe the path of the air by the dryer. The air is sucked into the dryer by openings in the surface of the machine. One fan drives the entire air through the dryer, but the fan is definitely the last step in the method.

It’s sucked previous the heating aspect and into the tumbler.

It enters the door and is directed down by way of the lint screen.

It passes by means of a duct in the front of the dryer and into the fan.

The fan forces it into the duct leading out the back of the dryer, at which point it exits your home.

The first thing that the air hits is the heating factor. After the air enters the physique of dryer, it is sucked by way of the heating element, and then into the clothes tumbler.

That is an ordinary nichrome-wire heating aspect, simply just like the heating ingredient in a toaster (see How Toasters Work for particulars on nichrome wire). This heating factor consumes lots of energy — 4,000 to 6,000 watts on most dryers.

The air is drawn through the heating aspect and into the holes in the again of the tumbler.

The steel stamping on the best, with the big holes in it, makes sure that air can enter the tumbler solely after it has gone through the heating ingredient.

The new air now makes its approach by the clothes in the tumbler, after which into the holes in the door.

The air passes by the holes within the door, and out by means of the large slot in the underside of the door which ends up in the lint screen.

The air is drawn via the lint screen and down a duct within the front of the dryer, the place it enters the fan.

The fan is a centrifugal kind 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 again of the dryer. Because of the ratio between the huge tumbler diameter and the tiny motor pulley diameter, no other gears are needed! It seems that the tumbler is one big gear (or truly a pulley), and the motor drives a tiny pulley. In the following part we’ll see what makes the tumbler spin.

You may see the skinny belt wrapped across the tumbler in the picture above. The black pulley gives tension — when the belt is hooked up, the pulley is drawn off middle, and the spring tries to pull it again. The belt loops by means of the silver pulley, by way of the black pulley after which around the tumbler. This provides the belt its tension.

The identical electric motor drives both the fan and the tumbler. The pulley for the tumbler belt is hooked up to 1 output of the motor, and the fan is hooked to the opposite. So what helps the burden of the clothes?

At the again of the tumbler is a flange, related to a easy bushing that allows the flange to spin. The again of the tumbler bolts to this flange. As an alternative, a system of gears, cams, electrical contacts and motors types a type of mechanical laptop. Let’s start by trying on the cycle management knob.

Cycle Change
By turning this knob to various positions, you can management each the kind of cycle and the length of time it runs. Let’s take a look at what is inside this swap. The picture beneath reveals the motor unscrewed from the change. Hooked up to the again is a little bit motor.

The tiny gear on the motor turns very slowly; and it engages a much bigger gear inside the switch that makes the swap flip even slower.

The motor turns the gear on the dial, which is connected to a set of four cams stacked on high of one another. Every of the cams engages one of many 4 contacts in the swap.

Every of the four contacts has a bend in it, and each bend is located at a unique height contained in the box. Beginning with the bottom left contact, the heights improve in a counterclockwise manner; the bottom left contact is the lowest, the highest left contact is the highest. A special cam engages each of those contacts. In the pictures beneath, you may see the 4 cam layers; each of these layers corresponds in peak to one of many contacts.

The cycle swap determines how lengthy the elements stay on. If none of the heating parts are on, only cool air blows through the clothes; if one is on, the air is heat; and if both are on, the air is scorching. In conjunction with the heat setting buttons, it additionally controls which heating components are on at a given time.

If you happen to press any of the top 4 buttons, they keep depressed. The next set of footage illustrates how urgent the buttons causes the plates to line up in other ways, elevating or lowering the bars that make the contacts. The primary change is positioned near the lint display. There are two temperature shut-off switches. A extremely neat set of plates that work like the tumblers in a lock make this characteristic potential, and likewise control which heating components are engaged. In the event you then press a unique button, the primary one pops up, and the new button stays pressed in. Relying on which button is pressed in, the plates open or shut varied combos of the contacts. When these switches attain certain preset temperatures, they break contact, which shuts the dryer off.

The image above exhibits the front of the dryer, with the front panel partially eliminated. This is where the second temperature swap comes in. If the temperature in the tumbler gets too hot, this sensor cuts the ability, shutting the dryer off. These holes are only there to blow sizzling air on the sensor each time they go by. Or if the fan gets clogged and no air is coming out of the tumbler? And to the left, you possibly can see a set of six holes in the outer edge of the tumbler. The first temperature sensor is on the appropriate.

The second sensor is situated close to the heating parts. If airflow is shut off for any cause, the air close to this sensor will rapidly heat up to the temperature that triggers this sensor, and the sensor will shut off power.