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Prototype Doser Frame

Rough draft.  Matt, this is ready to be reviewed but I have not yet given it a thorough look over and the drawings have not yet been imbedded.  I plan on two views of the proto-type that will give a good view of all the components and how they will work.

Abstract

A full scale proto-type is being created.  This model will allow us to run full flow/ full scale accuracy tests in the lab. Additionally, this model will be taken to the EP3 conference this spring.  With this proto-type we will be able to demonstrate the functionality and flexibility of our chemical doser.

Proto-type Design

The proto-type is made up of two main component: the structural frame work and the moving lever-arm.  All components will be fabricated using a modular aluminum framing system manufactured by a company called 80/20.  Affectionately called "The Industrial Erector Set," this company offers a wide variety of components along with an Auto-cad plug-in of each of their components.  With these tools, we have been able to design and evaluate multiple proto-types.  Additionally, their T-bar design will allow us to mount extra components that can be mounted with a standard "National Course" thread. 

The structural framework is designed with the same dimensions as the entrance tank except the actual tank measures 1 meter x 1 meter and our framework is 1 meter by ½ meter. This was done only as a space saving measure.  The height of our framework however is the same as the height of the entrance tank. Entrance tanks dimensions are based off the relationship between  the design flow rate through the plant and the headlosses within the plant and across the rapid mix tube.  Additionally, we need to accommodate the length of the rapid-mix tube and approximately 10 inches of free board. The actual values and results from these calculations are included elsewhere in this document but concluding, the height of the entrance tank and therefore our prototype is ***** meters high.

In addition, the frame work includes a table to hold a small stock tank and another table to hold the constant-flow device.  As determined in the design of the constant head device, there should be ideally 30 cm between the orifice and the low water lever of the stock tank.  This dimension has been taken into account in our design.

We have designed three different lever systems with the current-final lever presented here.


There are a number of constraints in the design of this lever arm.  First, we need to facilitate a way to attach the floats and counter-weight.  Secondly, we must have a way to adjust the distance the orifice travels down the arm.  It was also requested that the operators be given a means to manually "shut off" the flow. This can be accomplished by moving the orifice directly in line with the pivot.  We have also attempted to accommodate a second slide to facilitate attaching a second dosing pH control system.  It is preferred to both slides on the same side of the lever to allow the operator easier access.

As shown in our current design, most of these constraints can be met.  We are using a slide mechanism that has a manual "brake" which allows the slide to be clamped in any position.  We have not found a way to get both slides on the same side of the lever arm as their "open channel dosing tubes" would interfere with each other.  Currently, the slides are on opposite sides and could be awkward for the operator to manipulate.  However, each slide can be moved independently and can be moved to the center line to allow the operator to secure flow if needed. The floats and weights will be attached via the brackets at the endpoints.  

A material list is being created which lists each of these components, part number, quantity, catalog page number, price and associated fasteners.  This material list needs to be updated to reflect our most recent design once this design has been approved by all members of the team.  Also, in creating this list we found that some of our selected components were disproportionately expensive and modifications are being done to the frame to accommodate less expensive brackets.  These are small modifications and the design is near ready to be sent out for pricing and the components will be ordered.  Upon arrival of the parts, we will be able to build our full scale model, attach the hydraulic components and begin testing.

The AutoCad Drawing can be viewed Here

BLah - ignore the stuff written below, it's part of the template

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Bibliography

Deliverables

 By the end of the semester we intend to have a functional, full scale non-linear chemical doser.  In order to accomplish this, this sub-group needs to complete the following:

* Complete final changes to Autocad drawing to represent changes in the bracketing.

* Talk to Paul Charles about fabrication of the bushing and drilling of the lever-arm

* Update Material's List 

* Contact 80/20 distributor about pricing.  Plan to discuss the possibility of having them sponsor our frame

* Order and receive components.  Assemble according to Autocad Dwg.

* Install hydraulic components 

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