Working of a Dishwasher

Taken From: http://aaa-applianceparts.com/dishwasher.htm

All dishshwashers work in pretty much the same way. To understand how they work, let's look at these three areas:

• The motor and pump system
• The controls, switches, valves, and solenoids
• The interior

The motor and pump system

Your dishwasher has at least one motor. It is attached to a pump, which forces the water up into the sprayer arms. During the drain cycle, it also pushes the water out of the dishwasher…down the drain. A few European dishwashers use two separate motors, one for spraying and one for draining.

The motor is behind an access panel beneath the dishwasher. Some models have reversible motors, others don't. We will also discuss two older types that are not used in the newer dishwashers.

• If the motor is reversible, it is mounted vertically right in the center bottom of the dishwasher with the motor shaft pointed up. The pump is mounted atop the motor, then attached to the underside of the dishwasher. When the motor runs one way, the dishwasher pumps water up to the spray arms; when it runs the other way, it drains the water.

• If the motor rotates in a single direction, it is mounted horizontally, with the motor shaft pointed sideways, near the center bottom of the dishwasher. The pump is mounted to the end of the motor. The top of the pump is then mounted to the underside of the dishwasher. When the motor runs, it pumps water to the spray arms. To pump water to the drain, a mechanical arm integrated with the pump and motor activates, which diverts the water to the drain.

• Two other, older systems are becoming "extinct," in that they are no longer made.

• One is a belt-driven system. Its motor is near the front right corner of the dishwasher. The pump is mounted to the underside of the dishwasher at the center, and a tube-shaped belt connects the motor and pump. The motor is reversible: when the motor runs one way, the unit pumps water to the spray arms. When it runs the other way, the motor drives the pump to push the water out to the drain.

• The other system's motor rotates in only one direction. It's mounted vertically, right in the center bottom of the dishwasher, with the shaft of the motor pointed up, with the pump mounted atop the motor. The pump is then attached to the underside of the dishwasher. When the motor runs, it pumps water to the spray arms. To pump water out to the drain, a valve, completely separate from the pump and motor is activated. It diverts the water to the drain.

The controls, switches, valves, and solenoids

A dishwasher has at least three, but often six or more controls, switches, valves and solenoids. We will discuss these:

• Timer
• Selector switch
• Water inlet valve
• Float switch
• Soap dispenser
• Rinse aid dispenser
• Drain solenoid
• Thermostat
• Soil sensors
• Door switch
• Drying fan
• Heating element

• 
  

Timer

Dishwashers have a timer behind the main control panel at the front top of the dishwasher, or behind the lower access panel. It is either a mechanical device like a simple clock, or it's completely electronic with just a digital readout. The timer runs the dishwasher in a pre-determined pattern. It provides the electricity to all of the dishwasher components at the correct time, for the correct length of time.

Selector switch

A dishwasher usually has one or more selector switches on the main control panel at the top front of the door. The switch(es) allow you to choose among wash cycles, drying cycles (heat or no heat), temperature of the wash or rinse, and so on. The switches tell the timer which cycle options to engage.

Water-inlet valve

At the bottom left or right of the dishwasher, there's a water-inlet valve behind the access panel. This valve lets water flow into the dishwasher for the wash cycle. It is usually attached to the hot-water supply line, and to a tube that is then attached to the left or right side of the dishwasher. When the timer sends electricity to the valve, it opens and lets water into the dishwasher. The valve stops when the water level trips the float switch or when the timer stops sending electricity to the valve.

Float switch

Dishwashers have something meant to keep them from overfilling. This is usually a small switch attached to a float--a float switch. The float, which is usually cylindrical, is inside the dishwasher at the bottom, usually on the left side. As the water level in the dishwasher rises, the float rises too. When it reaches a certain height, the float activates its switch, which cuts the electricity to the water inlet valve. If the water-inlet valve is defective, the dishwasher may overfill.

Soap dispenser

Dishwashers have a soap dispenser located on the inside of the door. When the timer cycle calls for the soap to be emptied into the dishwasher, it either sends electricity to a bi-metal switch that opens it, or it mechanically opens the soap dish.

Rinse aid dispenser

Some dishwashers have a rinse-aid dispenser on the inside of the door. When the timer cycle calls for the rinse aid to be emptied into the dishwasher, it sends electricity to a solenoid switch, which opens the dispenser and measures rinse aid into the dishwasher.

Drain solenoid

Beneath some dishwashers, there's a timer-activated drain solenoid (an electro-magnetic coil) that opens a drain valve, to drain the wash water through a hose and out to the house's plumbing waste system.

Thermostat

Dishwashers have one or more small, cylindrical thermostats. These are a bit larger in diameter than a dime and have two or more wires attached to them. They protect the dishwasher, dishes, and humans by turning off the heating element that heats the water or the air in the dishwasher when it has reached its pre-set temperature. The thermostat automatically re-sets when the temperature falls to a lower level.

Soil sensors

Many of the more-recent dishwashers use multi-component soil sensors, which continually monitor the wash water during the wash cycle. These sensors help the dishwasher to wash for the amount of time that is appropriate for how dirty the dishes are, rather than for a pre-set period. When the water becomes clear enough, the sensor signals the timer to continue with the next cycle.

Door switch

Dishwashers have a door (or door interlock) switch that--if properly functioning--shuts off the dishwasher when the door is open.

Drying fan

Some dishwashers use a small fan to blow air (or heated air) into the dishwasher to dry the dishes faster. If your machine has a drying fan, it's beneath the dishwasher, usually in the back right corner.

Heating element

Dishwashers have at least one heating element--which is often a circular black tube at the bottom of the dishwasher under the lower spray arm. The element usually assists in heating the wash and rinse water to the proper temperature and/or assists in drying the dishes. Some dishwashers have another heating element integrated with the drying fan, to warm the air blown into the dishwasher to dry the dishes.

The interior

The interior of a dishwasher is where the dishes go. It contains the dish racks, the spray arms, and/or the tower that sprays water at the dishes, the upper part of the pump assembly, and the water filter.

As I ....

sit here on this cozy sofa and look outside at the quacking of the sea gulls, I realize how far have they traveled, have they come from the North Sea or have the come from the Atlantic Ocean ? Where have they been all through out the day, and have their thoughts wondered as to where are they and should be? Why are they here? Well then suddenly I realize that if they would have thought so much then are these creatures intelligent? Well they are defying gravity and flying and thinking, we walk, we don't defy gravity and we think, can we think like them? Well maybe they don't think, that is why the have to always search for their food and they eat whatever they want! That’s what we are powerful in! THINKING!!

Whenever I get up in the morning, the first thing I think of is that I have to put my right foot down (well I am too orthodox at times) , well is it orthodox, no its all about what I think is recalling certain things, just to see that certain things which I have carried forward are not forgotten ! Well this also include my dreams, this gives me an indication , that I have not yet forgotten the Dreams, the Dreams to Fly High and think , and think to be the one what I have always wanted to be. The dreams here are not always well defined, they are dreams, because they have not been either fulfilled or there is something which is preventing us from making them a reality. What can it be? It can be anything starting form failures to disappointments to lack of focus.

Failure is something which I have learned from my life and hence the small places where I get success I tend to be very happy and I enjoy and celebrate it. But then I hate sharing my success, that’s a fact, the whole world must be knowing about it, but then the one most important part of it always becomes a secret and I think that during the time of failure its very important to always use that secret not as a weapon but as a Diamond, which when rubbed, though would shine but would cut away the failure! That’s my way of succeeding in life!

Then why do I fail! Wish I could answer this question! However, there is an important part of life and that is what I need to understand is that about being focussed! Well, for me my Physics was always weak , but optics always strong, hence I dont seem to understand that why I have not been able to take out the focal length, might be that it had all to do with the temperature! Temperature? Well the temperature here is the state of mind, where in there are so many things going into your mind, all the cells causing heat due to abrasion and where in I cannot think right! Ah! what a stupid concept to come up with , well it might be a stupid concept , but then why do people say "keep your cool", well no theory as such to be defined here, but then its all about thinking what you would like to do in your life, when you are tension free, and let that be an extinguisher when you see that your mind is on fire, that’s because you know you have set your focal point right, and you know what you want to do in your life! Well there was part of me, where in I was all confused and lost! But then this time I know what I have to be! It’s not a calculated risk but a certainty of occurrence and what I need to understand is that I can do it! So grab a coffee and think what you have to so and you cool yourself and believe me it will help.