Designing a Motorized Chalk Eraser to Reduce Effort

In summary, the conversation revolves around designing an eraser that can act like a vacuum cleaner to eliminate the dust from a chalk eraser. The person asking has questions about the feasibility and calculations involved in such a design, as well as the use of a fabric roller to erase the chalk from the blackboard. Suggestions are given to look at miniature vacuum cleaners and home improvement store set-ups for inspiration and to test different cloth types for the fabric roller. Calculations for capture velocity and fan laws are also mentioned. Overall, the conversation is focused on finding ways to make the eraser design efficient and effective.
  • #1
well,im thinkin of designing an eraser,specifically the conventional chalk eraser, that can act like a vacuum cleaner,in the sense that i would have to put a motor in it,for the reason that the user would have to use a lesser effort for him to erase something,nd no chalk dust...well u could say that it is nonsense,but is this possible to do,and definitely,it must be small like other eraser and no plugs,just battery..
if its possible,where shud i start the design..tnx a bunch..
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  • #2
Have a look at miniature vacuum cleaners used for photographic applications.
  • #3
As design inspiration, take a look at the vacuum set ups they use with drywall sanders in home improvement stores. They work pretty well and it would serve the same purpose.
  • #4
well,i actually do have a design now..but would just like to ask wat r the calculation that i shud have with this one..because my prof requires us to show calculations of our design..
i made an eraser,just like the conventional in shape and size, has a roller and a brusher, that would eliminate the dust in the fabric's surface and the vacuum setup on top, but really can't frigure out, if it would work,what r the things that i cud compute and how should i do wud i know,if the pressure is enough, and bout the motor speed,coz i was thinkin if it can b powered by a battery,, 4 AA enough, to power the motor and the fan as well..what other things should i consider?tnx..
  • #5
What you are trying to calculate is "capture velocity." This is basically the speed that the air needs to travel in order to "grab" the chaulk dust and hold it until it is moved through a channel or passage to where you want to deposit it.

The capture velocity of very fine powder and dust is 2000 FPM.

If you do not produce this velocity of air the dust will fall out of the air and accumulate on the duct or passage, or won't be picked up at all.

The calculation is simple enough: Q=AV

Q = Quantity of air in Ft cubed per minute (CFM)

A = Cross sectional area of orifice in square feet

V = velocity of air in feet per minute

Perhaps with a beater-bar type arrangement lifting and throwing the dust and short enough run to the depository for the dust this velocity could be reduced some.
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  • #6
tnx a lot..its really a big i have to compute the right sizes of shafts for the motor..or its not i really have to have a powerful capture velocity,that large..since i do have a brusher..all i need is something that can suck the dust..up to the compartment.
  • #7
Considering you are capturing the particles in a enclosed area, close to the orifice, I discovered that you can reduce the rate down to only about 150 fpm. The higher velocity capture rate was for dust in open air.

Check out the fan laws and relate them to the fan you are planning to use to determine the capacity it will move the air at what RPM and HP."
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  • #8
well..bout the formula u've given..i was actually luking for the right cross sectional area,since i don't have an idea bout the value of Q...
and would just like to ask,can a fabric in a roller erase a chalk from a blackboard,moving it laterally,coz someone tells me it can't..but i still insist it can..maybe depending on the it possible?
  • #9
titus_polo said:
can a fabric in a roller erase a chalk from a blackboard,moving it laterally,coz someone tells me it can't..but i still insist it can..maybe depending on the it possible?

I would say this would be a good thing to test with a prototype or model. A prototype doesn't have to be exactly like the invention, just needs to test the function of the components. Create a roller and try different types of cloth.
Even just moving it manually, just to see if the cloth will remove the chaulk. Even just moving the cloth laterally across the blackboard by hand will give you an idea if it could do what you intend.

1. How does a motorized chalk eraser reduce effort compared to a manual one?

A motorized chalk eraser eliminates the need for physical force to erase markings from a chalkboard. This reduces the effort required by the user and can also prevent hand fatigue.

2. What features should be considered when designing a motorized chalk eraser?

Some important features to consider include the type of motor used, the speed of rotation, the size and weight of the eraser, and the power source. It is also important to consider the material used for the eraser tip to ensure effective erasing.

3. Can a motorized chalk eraser be used on all types of chalkboards?

It is important to consider the type of chalkboard when designing a motorized chalk eraser. Some erasers may be more suitable for certain surfaces, such as traditional blackboards or newer whiteboards. It is important to test the eraser on different surfaces to ensure optimal performance.

4. How does a motorized chalk eraser affect the environment?

A motorized chalk eraser may have a lower environmental impact compared to disposable chalkboard erasers. However, it is important to consider the energy source used to power the motor and the materials used in the eraser's construction. Using renewable energy sources and eco-friendly materials can reduce the environmental impact.

5. Can a motorized chalk eraser be used by individuals with physical disabilities?

A motorized chalk eraser can be a useful tool for individuals with physical disabilities, as it eliminates the need for manual force to erase markings. However, it is important to consider the design and accessibility of the eraser, such as the placement of buttons and the weight of the device, to ensure it can be used comfortably by individuals with different abilities.