P18414: SOIL Composting Toilet and Urine Management
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Preliminary Detailed Design

Table of Contents

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Team Vision for Preliminary Detailed Design Phase

Summarized below are both our intentions and actual accomplishments this phase:

High Level Overview of Design Development

The main goal of this phase was to use multiple methods to gather insight as to what design elements we should be moving forward with. This was done through ergonomic research, CAD modeling, and physical prototype testing.

In order to keep our clients up to date with out project plans, weekly calls took place every Thursday. During these calls, questions were asked about both toilet specifics, and characteristics they specifically wanted implemented in the toilet design. From the beginning of the design process, we have tried to make a strong effort to include our clients in every decision we made.

Our PDDR mapping can be found here.

Notes of the weekly meetings can be found in the attached pdf.

Diverter

Initially going into this phase, as a team we planned to move forward with the development of two distinct diverter concepts: the slotted slope and the U-shaped mold. While we still plan to continue developing the U-shaped mold, at this point we have not yet been able to prototype a physical model. However, a CAD model for the diverter has been created with specific dimensions and stress testing has been completed virtually.

The slotted slope diverter has been modeled with a physical prototype. To shed light on the optimal slots to apply to the slope, multiple diverters were formed with varying slots. Small holes and large slots were formed into the models, as a team we planned to also test vertical and horizontal slits, however, the machinery in the RIT construct could not cut the slits into the ABS plastic we used.

Prototyping and Modeling

To create the slotted slope prototypes sheets of ABS plastic were utilized. Measurements were taken from the interior of an actual toilet to approximate the frontal slope as closely as possible. After taking these measurements, the plastic was formed to the proper dimensions. Small and large holes were then implemented using respectively sized drill bits. A stand to hold the diverters in place was also created using the ABS plastic. This ensured that no motion occurred during the testing process. A rubber lip was also added to the bottom of the diverter. While at this point in the process, the lip did not divert to the same flow as the slots, the percentage of separation between the slots and the lips could ultimately help with deciding which design to move forward with.

Photos of the different slotted slope prototypes can be seen below.

Slotted Slope Diverter with Large Holes

Slotted Slope Diverter with Large Holes

Slotted Slope Diverter With Snall Holes

Slotted Slope Diverter With Snall Holes

In addition to the modeled plastic diverter prototypes, additional prototypes were created in CAD to give us an understanding on the dimensions and size within the complete toilet system. The CAD drawings can be seen below.

U-Shaped Diverter Front View

U-Shaped Diverter Front View

U-Shaped Diverter Isometric View

U-Shaped Diverter Isometric View

U-Shaped Diverter Side View

U-Shaped Diverter Side View

U-Shaped Diverter Top View

U-Shaped Diverter Top View

The CAD models of the diverter were then used to simulate stress testing to see where the diverter would ultimately yield first. The analysis can be found below.

U-Shaped Diverter Table

U-Shaped Diverter Table

Diver Stress Testing

Diver Stress Testing

Additional testing was also done to test the feasibility of the cover material with the size of the holes of the diverter. It was a concern that the cover material may clog the holes of the diverter and make cleaning a pain. The analysis for this report can be seen below.

Cover Mater Compatibility

To help decide the choice of material, a subject matter expert of Caribbean Glass was reached out to. The following image shows the entire conversation at this point.

Caribbean Glass Conversation

Caribbean Glass Conversation

Haiti plastics was also reached out to again, but we are still waiting for a response.

Feasibility: Analysis

From the initial testing that was completed to test percentage of urine diverted, we were able to see preliminary results. While the true percentages of urine diversion could not be acquired from the test protocol due to unforeseen circumstances, we were able to learn that the slotted slope design would divert a high percentage of urine through the slots, around 90%, and what wouldn't be captured by the slots would likely be captured through the added lip at the bottom.

This protocol was repeated a second time with more precise methods for measuring the volume of water accumulated in each section of the testing.

These protocols can be found below.

Force Diverter Can Withstand.

Percent of Diverted Urine v1

Percent of Diverted Urine v2

CR Observed: Amount of Splashback

Pending Analyses:

Slotted Slope Compatibility With Cover Material

Corrosion Due to Cleaning Material

Feasibility: Misc. Documentation

As we move forward with the design testing, it is necessary that we recruit human test subjects. Using authentic human subjects will allow us to gather information on comfort levels and general toilet experience. These human subjects will also provide a more realistic simulation for the accuracy of the urine diverter. Although the diverter had been tested using a punctured water bottle as a simulation device, this was mainly for feasibility purposes to see if the design was worth moving forward with. Having actual human subjects will create a much more realistic scenario for the urine diverter.

In order to have human subjects, a human subjects form was filled out. The informed consent document that we will also be providing to our subjects can be seen below.

Human Subjects Testing

Informed Consent Form

Base

While improving the urine diverter has been the main focus of this project, it is also important to analyze the size of the base of the toilet.

Analysis was also completed to explore the possibility of inserting pockets into the base of the toilet.

Container Pockets

Prototyping and Modeling

The majority of the prototyping and modeling for the toilet base has been done with an ergonomic perspective. A SOIL provided document for the construction process has been reviewed and will ultimately serve as a guideline for constructing the base of the toilet at RIT for future testing.

The documents for this construction can be found here and here.

Feasibility: Analysis

While we did not have a complete toilet prototype at this point in the design process, initial protocols were written with the intent of testing our engineering metrics on the complete toilet system.

Preliminary research was done to analyze how the different user demographics interact with the toilet. Images can be seen below.

Toilet Width

Toilet Width

Toilet Height

Toilet Height

Toilet Depth

Toilet Depth

Ergonomic analysis on the toilet base was completed. Conversations with subject matter experts took place and the notes for the conversations can be found here. The tests written for the toilet base can be found below.

Seat Surface Height From the Ground

Seat Width (diameter)

Additional tests for the toilet base that did not concern an ergonomic point of view can be found below.

Force Toilet Can Withstand

Collection Container Accessibility

In addition to the test for collection container accessibility, input from the industrial designer helping with the final design can also be seen below.

ID Involvement

The pending analyses for the toilet base can be seen below. These tests plans will be completed once a complete toilet system is acquired.

Volume of Water Permeated at a Particular Depth

Size of Largest Gap

Range of Motion of Seat When in Use

Relative Humidity Within the Toilet

Weight of Toilet

Toilet

Prototyping and Modeling

While we did not have a complete toilet prototype at this point in the design process, initial protocols were written with the intent of testing our engineering metrics on the complete toilet system.

Our updated systems architecture can be seen below.

Updated Systems Architecture

Updated Systems Architecture

CAD images of the toilet can be found below.

Toilet Cross-Section

Toilet Cross-Section

Isometric

Isometric

These CAD drawings were also used to simulate stress testing. The results of that testing can be seen below.

Frame Stress Table

Frame Stress Table

Frame 700 N Stress Test

Frame 700 N Stress Test

Frame 66000 N Stress Test

Frame 66000 N Stress Test

Stress Analysis Report

Feasibility: Analysis

The test protocols written that concern the toilet system as a whole have not yet been tested because we currently do not have a complete toilet prototype. However, the anticipated test protocols can be found below.

Number of Components

Cost of Toilet

Bill of Materials (BOM)

A Bill of Materials (BOM) is being developed to anticipate the cost distribution of the project. This document will help to aliquot our budget in the most efficient manner as possible. This document is not yet complete, but the draft can be found below.

Bill of Materials

Test Plans

Test protocols were written based off of the document done in a previous phase where the engineering metrics were mapped to potential test plans with an idea of targets and confidence intervals.

Testing of Engineering Metrics

A complete directory of the test plans can be found below.

Force Diverter Can Withstand.

Percent of Diverted Urine v1

Percent of Diverted Urine v2

CR Observed: Amount of Splashback

Slotted Slope Compatibility With Cover Material

Corrosion Due to Cleaning Material

Seat Surface Height From the Ground

Seat Width (diameter)

Force Toilet Can Withstand

Collection Container Accessibility

Volume of Water Permeated at a Particular Depth

Size of Largest Gap

Range of Motion of Seat When in Use

Relative Humidity Within the Toilet

Weight of Toilet

Number of Components

Cost of Toilet

Risk Assessment

While risk analysis has been completed for the previous two phases already, it is important that additional risks be added as the project develops.

The image below highlights the main risks that were encountered during this phase and the complete risk document can be found directly under the image.

Risks for Phase 3

Risks for Phase 3

Phase 3 Risk Document

Design Review Materias

This section will be populated as we receive feedback from the phase review.

Plans for Next Phase

As we continue our design execution into the next phase, the Detailed Design Phase, we plan to uphold both individual visions and a group vision.

The pdf for the group plan can be found here and an image of the plan throughout the remainder of the semester can be seen below.

Detailed Design Group Plan

Detailed Design Group Plan

Individual Visions:

Jeff

Nicole

Chris

Tessa

Rozie


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