• Created by user-8da17, last modified by user-4b5d1 on Dec 09, 2009

Prototype Doser Frame

Abstract

A full scale proto-type was designed and built.  It was built to scale to represent the alum doser as it is positioned in the entrance tank of an Agua Clara water treatment plant.  The model allows us to run full flow/ full scale accuracy tests in the lab. Additionally, the 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 comprised of two main components: the structural frame work and the moving lever-arm.  The frame components are constructed using a modular aluminum framing system manufactured by 80/20 Inc.  Affectionately called "The Industrial Erector Set," this company offers a wide variety of components along with a down-loadable Auto-cad plug-in of their components. With these tools, we have been able to design and evaluate multiple proto-types. Additionally, the T-bar design of the framework extrusions allows us to mount extra components with any standard "National Course" thread.  All accessories are readily available and are purchased through McMaster-Carr.

The dimensions of the structural framework are based on the actual dimensions of the entrance tank of the Agalteca plant.  We have reduced the width to 1/2 meter as a space/material-cost saving measure but otherwise accurately reflect the entrance tank dimensions.   Entrance tank dimensions and elevation are a critical criteria in plant operations.  Head losses throughout the plant must be accounted for in the entrance tank.  Furthermore, the addition of the physical parameters of the rapid-mix tube have added to the depth of the entrance tank.  Full analysis of these parameters can be found on the Agalteca Page

The frame work also includes a table to hold a small stock tank and another table to hold the constant-head tank. Ideally, as determined in the design of the constant-head tank, there should be 30 cm between the orifice and the low water lever of the stock tank. This dimension has been taken into account in our design.  Figures 1.0 - 1.2 illustrate our prototype from various views and a full description of each component follows.

Fig 1.0 Isometric View

Fig 1.1 Top View

Fig 1.2 Side View

Components

Lever Arm
The lever arm is a 1" x 1" T-slotted aluminum-extrusion bar as classified by 80/20 Inc. as 1010. The length of the lever arm is a critical dimension for Alum dosing and is calculated in the Dual Scale Child page.  This length of 0.80 meters accounts for the variation in the water level of the entrance tank resulting from changes in plant flow.  The lever arm is attached the pivot rod with a clamp which is then attached to two side bearings on the frame.  The accessories were purchased through McMaster Carr.   The lever is positioned in such a way that the slide can be positioned directly under the pivot providing a manual shutoff.

Slide
The slide is a component from 80/20 Inc. (Part # 6730) that we attach the orifices to. There is also a hand brake that is attached.

Brake
 

Fig 1.3 Slide and Brake

The brake keeps the slide in place, also a component from 80/20 Inc. The brake naturally keeps the slide in place, while pushing on the area shown on the diagram relieves the pressure and allows for the movement of the slide

Float and Counter-Weight Connectors
Also shown in Figure 1.0 are the eyebolts that will be used as attachment points for the float and counter-weight (should we decide to use one).  These items will be attached using mono- filament fishing line.

Stock Tank
The stock tank will sit on the triangular table that is pictured. The table for the stock tank is 24.13 cm (9.5 inches) tall to provide enough head to demonstrate how our system works.

Constant Head Tank
The constant head tank is maintained on this platform.  The platform is adjustable by loosening the attachment points to allow accurate leveling.  This is a critical height as the water level in this tank must be in line with the orifice when the lever-arm is horizontal.  

The AutoCad Drawing can be viewed Here

h.3 Assembled Prototype

The prototype was assembled and hydraulic components attached. The following two drawings show the assembled structure and key components are labeled.


Useful 80/20 information

 80/20 Inc. is a manufacturer of modular aluminum framing system.  80/20 components are used extensively throughout our lab and specifically in this project.  This section provides some details to assist getting started with these components and using them in design. 

http://www.8020.net/; This is the main web page for this company.  Available is a complete on-line catalog, price catalog and design ideas.  Design is made easier using their "Auto-cad Plug-In."  All components and frames are available with this Plug-In requiring only limited Auto-cad knowledge for a professional looking design. 

This Plug-In, called Auto-Quoter, is used by the distributors to generate a price-quote.  Auto-Quoter can be downloaded on to any computer that is running Auto-cad and is free.  This program leads to greater accuracy when ordering and less chance of error as the Bill of Materials is generated directly from the Auto-cad drawing.

 Two local distributors are: 

Ralph W. Earl Inc.
5930 E.Molloy Rd.
Syracuse NY 13220
315-454-4431
rwearl@rwearl.com
Specifically- Bob Prosher:bproscher@rwearl.com.  Competent and helpful salesman.

Hughes Industrial
9685 Main St.
Clarence NY 14031
800-759-8374
www.hughesind.com

 Ordering Information

Bill of Materials.pdf  as generated by the AutoQuoter program and is attached.  Bob Proscher from Ralph W. Earl Inc was able to procure a 40% discount for us on materials.  The order for these components was submitted to Christene Day on November 17,2009 and parts were received on November 30, 2009.  We are currently waiting on receipt of the materials to continue on the project.

Bibliography

Deliverables

All semester goals were met concerning this aspect of the project and are summarized below:

  • Proto-type was designed. Autocad drawing created
  • Components ordered and received.
  • Model assembled
  • Hydraulic components attached including orifice, clip, stock tank and constant-head tank.
Outstanding
  • As this is a model of what will ultimately be used in Honduras, the assembled model needs to be fully evaluated for ease and practicability of use. Additionally, components for the Honduran doser need to be purchased. Once accomplished, a full doser material list will be added to the wiki.
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