Final Design

        The Layered Dome design is the most sturdy design choice, using three large pieces of acrylic instead of many small, brittle pieces that have many points of potential fracture.  The Layered Dome design also offers the best symmetry of water flow channels.

Fabrication Process:

The Layered Dome, requiring a 3D CNC Machine, was sent to Tom Shalfant at UCSD’s Machine Shop to fabricate.  Tom required a Solidworks file of the three pieces and the material.  With enough time and effort, Tom was able to cut away the dome, water channels, and manifolds of the Layered Dome .  Additionally, the team fabricated handles on the 2D CNC to easily manipulate the dome.  

        The main purpose of the sampling manifold is to extract water samples. This manifold was connected to the main tubing of the system.  There are five solenoid valves attached to the manifold. At the other end of each solenoid is a sample bottle that collects the sample water. Moreover, an additional solenoid valve was implemented at the end of the manifold to help direct the flow of water into the sample bottle. The additional solenoid valve is normally open, enabling water circulation in the closed loop system in between collection of samples. When a water sample needs to be extracted, the microcontroller would close the additional (“+1”) valve and redirect water to one of the five solenoid valves that is open and into water sample bottle. Fabrication Process:

The process of fabricating the polycarbonate manifold required one of the concerns for the project is the stagnant water in the system.  To minimize the stagnant water in the system, the length of the tubes connection to the manifold and the solenoid valves are cut to the minimum. Also, the stagnant water collected is the same in each sample bottle. When plotting the concentration of trace metals vs. time, this proportional error will not affect the calculation of the leach rate of the paints. Another limitation is the size of the solenoid.  When we crafted the manifold, we tried to keep the manifold as short as possible.  To accomplish that task, we separated the solenoid valve into smaller pieces in order for us to screw the solenoid valve to the manifold.  The top portion of the solenoid valve contain a piece of metal that is normally down. When power is supplied to the solenoid valve, the top portion of the solenoid valve creates a magnetic field and pulls the metal gate up. By disassembling the solenoid valve, we were able to cut the distance that is required for the manifold by almost two thirds. Thus, reducing the weight of the manifold and decreasing the distance for the water to circulate through the system. 

User Interface