Our concept criteria started with the original design of the wind tube that we got from an exhibit at the San Francisco Exploratorium. The design has undergone some changes to meet challenges that arose during the design and construction phases. One of the things that we were facing was cost constraints; finding a large enough plastic sheet in our price range to fit our application was very difficult. Therefore, we decided to re-configure our original design which turned out to have an advantage. With the new support frame design, we increased the durabilty of the tube. This will increase its longevity at the Children's Museum of Klamath falls. Another idea to improve the air the flow inside the tube has been implented into the tube design. The new design will have a cirucular fin that will concentrate the inlet flow of the air, and there will be another fin towards the top of the tube that will disrupt the outlet flow air, as shown in the picture below. This new set up will prevent the objects in the tube from shooting out the top at a higher velocites, and blowing the objects all over the room.
Another criteria for the project is the level of safety that the wind tube must provide. Children will be interacting with the wind tube, and there must not be any way that they can become injured by using the wind tube. All of the electronic components must be contained inside of the base of the wind tube. Since there is an electric motor that operates the fan, there is a substantial amount of power that could harm a child if they had access to any wiring. Another area that must be considered is the fan. The fan is made out of a plastic material, but could still do damage as it rotates at several hundred revolutions per minute. If a child was able to fit their hand or fingers in between the screen it would create an unsafe environment. The wind tube must also be sturdy and be resistant to tipping over. The wind tube is going to be pushed and pulled on by the children. Since it is four feet tall and will be up on a counter, it is possible for the wind tube to be pulled over. The wind tube must be able to withstand this abuse and have a solid base so that the children won't be able to pull the wind tube over on top of themselves.
The wind tube needs to be very user friendly. The children using the exhibit are generally younger school age kids, so the design can't be complex. The switch needs to be easy to locate and operate, and be substantial enough to take years of abuse by kids. They need to have a general idea fo how the wind tube works when they approach it. They will be able to jump in and start learning quicker if they have to concept in their mind of what will happen when they turn they knob. It also needs to be able to accomodate as many kids as possible. The wind tube is designed so that multiple children can be occupied at the same time without excessive waiting to use the wind tube.
Another criteria for the project is that it must be lighweight and easy to move. In the original design, the frame of the wind tube was going to be welded together. This would make a sturdy structure but would make moving and transporting the wind tube more difficult. To make the wind tube easier to move, we have decided to use fasteners to connnect the tube to the base. To improve the weight of the tube we have also decided to use aluminum. This will provide a solid metal sturcture while still yielding a light weight product. We will also be limiting the amount of materials used to save as much weight as possible. The goal was to keep the design to approximately 30 pounds. According to SolidWorks analysis, the wind tube assembly should be close to this mark.