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Most people use their washing machine hundreds of times throughout their life without ever knowing what goes on inside.
Sure, you may know about the washing machine door or washing machine tray. But, how does a washing machine work? What drives the agitator to switch directions?
Why is the appliance so heavy? How does it not leak water despite spinning the clothes so fast? What are the parts of a washing machine?
Before we take apart the machine and explore each of the parts and what they do, let’s touch on how to use a machine correctly.
And if somebody has jokingly sent you to this article - don't worry! In just a few minutes we'll give you enough facts to be an expert on washers and put that person to shame!
How To Use A Washing Machine
If you’ve spent any time in a launderette waiting for your clothes to be clean, you have a good idea of how the process works.
Before you begin to load your clothes, you must decide a few things:
The Typical Cycle - In A Nutshell!
First, the drum fills with water after you start the washing machine. Then, the agitator stirs the clothes around.
The washer then drains the water after some time agitating, and most of the water is removed through fast spinning.
Next, it refills with water and agitates again to remove the soap.
Lastly, it drains through the washing machine waste pipe and spins again.
What's Inside A Washing Machine
If you have ever tried to move a washing machine, you know it is terribly heavy. That’s because there is at least one big block of concrete in there!
The concrete is needed as a counterweight to the electric motor, which is just as heavy. The motor drives the gearbox, also quite hefty, which is attached to the steel inner tub. A washing machine has plenty of heavy components.
There are two steel tubs in a washing machine. The clothes are inserted into the inner drum. During the spin cycle, the water leaves through the perforated holes on the sides. There is usually an agitator in the middle of the tub.
All of the water is sealed in by the outer tub, which is bolted to the washer’s body. The inner drum must be installed in a way that allows it to move without hitting other machine parts since it shakes and vibrates during the wash cycle.
The gearbox is attached to a metal frame inside the appliance, and the inner drum is attached to the gearbox. The frame also holds the concrete weight and motor.
If one side of the frame moves down, the other side will move up thanks to a system of three pulleys. This supports the heavy components’ weight so that the entire machine doesn’t shake when they move.
A vibration damping system in the machine uses friction to absorb some of the vibration. A mechanism that is similar to a disc brake is in each of the four corners of the appliance. A spring squeezes two pads against a metal plate attached to the frame.
This video is also very good for learning how a washing machine works.
Where Does The Water Come From?
A washer's plumbing fills the machine with the water temperatures of your choosing, recirculates the wash water from the bottom of the tub to the top during the wash cycle, and pumps water out through the drain during the spin cycle.
On the back, there are hookups for cold water and hot water lines. And, using hose connectors, both lines are hooked up to the solenoid valve’s body. Two valves feed into a single hose within the solenoid valve.
This is because either the cold valve, the hot valve, or both valves will open depending on the temperature selected and then feed into the single hose.
The Anti-Syphon Device
The water goes through an anti-syphon device before the hose releases it into the inner drum. The anti-syphon device keeps wash water out of the water supply lines, which could contaminate the water for an entire neighbourhood.
This plastic device allows air in through a big opening. Water shoots in from the washing machine hoses into the device, turns downward, and exit through the tube on the other end. The water is open to the atmosphere while inside the device. This makes it so any suction on the water supply line will only get air instead of sucking water in from the washer. Some models use washing machine non-return valves.
The washing machine also has an overflow port. This is connected to a pipe that dumps water onto the floor out of the bottom of the machine. This may seem like a bad idea, but the overflow port protects the motor from getting wet if the tub overflows.
Where Does The Water Go?
The pump is the main driver of the rest of the plumbing system. It is the part that drains the appliance and recirculates the water.
The pump actually consists of two separate pumps. The top pump recirculates the wash water and the bottom part of the pump goes to the drain line.
The trick is knowing when to pump the water back into the tub and when to send it out the drain. The pump’s motor is able to reverse direction.
When the washing machine is draining the water during a spin cycle, it spins one way. Then, when the washer is recirculating the water during a wash cycle, it spins the other ways.
The fins, or vanes, of the bottom half of the pump force the water around and push it out of the outlet and the pump after it enters the inlet of the pump.
Since the pump operates in both directions, the outlet and inlet switch depending on the direction.
The Pump Direction Determines What Each Pump Does
The bottom pump tries to pump water back into the bottom of the tub from the washing machine drain hose, and the top pump pumps the water it sucks from the bottom of the tub back up to the top when it is spinning counterclockwise.
And, the top pump sucks air from the top of the tub and forces it through the bottom, while the bottom pump forces water sucked from the bottom of the tub out the drain hose when the pump is spinning clockwise.
Before heading back down to the drain, the drain hose loops all the way up to the top of the washer. The level of water inside this hose will be the same as in the tub since one end of the hose is open to the atmosphere and the other is hooked up to the bottom of the wash tub.
The drum would never fill all the way if the drain hose did not go all the way to the top. Water goes out the drain as soon as it reaches the bend in the hose.
The Washing Machine Clutch
The washing machine pump is hooked up to the motor using a clutch. This is useful when the pump doesn’t spin at all and the washer churns the wash tub water without recirculating it.
The clutch is attached to the pump using a flexible coupling. The coupling must be flexible because the pump is mounted to the stationary outer tub while the clutch and motor are mounted to the frame which moves freely with the inner tub.
A set of four teeth on the bottom of the clutch stop rotating when the electromagnet is engaged. The clutch engages once the teeth are stopped, and it locks up to the motor shaft after a couple of revolutions, which causes the pump to turn with the motor.
This is a good video showing the difference between a worn clutch and a new one.
How Does the Drive Mechanism Work?
The drive mechanism forces the water out by spinning the entire inner tub and agitates the clothes by moving them back and forth inside the tub. These two jobs are handled by a gearbox.
This is done with the same method the pump uses. The gearbox goes into the spin cycle when spun in one direction and agitates when it spins in the other direction.The gearbox holds the inner drum and is sealed to the outer tub by a piece of rubber.
On the other side of the washing machine seal, the inner tub is mounted to the flange of the gearbox using bolts. From the centre of the gearbox extends a hollow tube.
A splined shaft is inside this tube, and the spline at the top of the shaft hooks into the agitator.
The Washing Machine’s Controls
Today’s smart washers are much more complex than the washing machines of yesteryear, but since we are providing a simple crash course, we are going to look at how your average washer works.
First of all, there is the cycle switch. This component determines the length of the cycle’s different parts.
A tiny motor with a big gear reduction is located inside the switch. This makes the dial turn slowly. There are contacts in the top half of the switch.
Small metal pieces in the dial’s plastic arm cause the contacts to open and close. Bumps on the dial lower and raise the metal pieces as the dial spins.
The dial’s bumps have a slope on the front that gradually raise up the pieces of metal. But, they do not have this on the back. Therefore, the pieces of metal hit the bumps when you try to turn the knob backwards. This is why the washer dial only spins one way.
The program that operates your washer is essentially the bumpy plastic disk. The duration of the cycles is determined by how long each bump is. The duration of the appliance’s pause before the next task is based on the space between bumps.
Temperature and Speed Control Switches
The cycle switch is much more complicated than the temperature and speed control switches. They determine if the solenoids for the water supply will open or close during the rinse and wash cycles and control the speed of the motor.
When the machine fills, just the hot solenoid will open if hot is chosen. Just the cold solenoid will open when cold is selected. And, both will open when warm is chosen.
Two contacts are engaged by each plastic rocker. This either closes or opens the contacts’ circuit. There’s always an open and closed contact set for each switch.
To determine the drum’s water level, the level sensor utilizes a pressure switch. The amount of water that goes into the tub depends on the pressure switch.
The hose’s small end connects with the switch, while the big end connects with the bottom of the tub. Water rises in the hose as the drum’s water level rises. The air is compressed as the level of the water rises because the hose’s air is trapped.
A little piston is inside the switch’s housing. The piston is pushed up by the hose’s pressure. It pops and closes the electrical contact once it is raised far enough. You can adjust the point where it loses contact.
Know somebody who is completely clueless when it comes to the washing? It might even be your spouse, who still seems to think they can fix everything.
Whoever it may be, share this article with them!
And for more great information, check out our post on "The History Of Washing Machines".