P19318: Thermochemical Conversion of Food Waste
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Detailed Design

Table of Contents

Team Vision for Detailed Design Phase

The goal for this phase is to complete the subsystems not addressed in the previous Preliminary Detailed Design phase. By the end of MSD I, we want to have all the necessary components to be ready to purchase and build by the beginning of MSD II or hand it off to another team if needed. Similar to the last phase, the subsystems were categorized into the system integration side and the electronics side. These deliverables led to a concurrent work approach as we did in the last phase. The activities were based on the three week plan template from the end of the Preliminary Detailed Design phase and can be found here

Subsystems To Be Addressed

System Integration Electronics Subsystems
Drilling test plans Protective case for electronics design and documentation
TC clamps design and documentation Mother/daughter board configuration
TC test plans Electronics BOM
Electronics test plan

By the end of the phase, the team was able to address all the subsystems that were planned. Moving into MSD II, we feel we have the necessary documents to start building certain subsystems and writing our test plans for the engineering requirements. The BOM for the electrical components and the broad electronics test plans are still subject to review until the end of the semester by the team. No lead times were sufficient enough to begin purchasing at the end of MSD I.

System Integration Feasibility

After the preliminary detailed design review, our original thermocouple mount had several weaknesses that needed to be addressed. We started this phase brainstorming alternative designs and arrived at the design shown below. We also needed to start determining how to protect and enclose the sensitive electronics so a preliminary case was designed that we will test and modify starting in MSD II.

System Drawings and Schematics

TC Mount Assembly Drawing Page 1

TC Mount Assembly Drawing Page 1

TC Mount Assembly Drawing Page 2

TC Mount Assembly Drawing Page 2

Electronics Feasibility

After the feedback from the preliminary detailed design review the plans for the circuitry were changed to have a main board with a Raspberry Pi and multiple smaller daughter boards that can each be separately configured for different sensor types.

The initial design will have at least two of these boards designed for thermocouple probe operation while the remainder are up to the customer for how they may or may not be used in the future (this method was chosen because it is more easily expandable).

The main board would be mounted together with the Raspberry Pi and connect to the daughter boards. Its wiring schematic diagram may be found here.

Main Board Design Schematic

Main Board Design Schematic

The daughter boards will be mounted in a stack and connected separately to the main board via cables. The diagram for a thermocouple-based daughter board may be found here.

Thermocouple Daughter Board Design Schematic

Thermocouple Daughter Board Design Schematic

The main board schematic file details the connections to the Raspberry Pi and the individual daughter boards. The connectors for each daughter board will be present but not all boards will be connected. The 8 boxes on the left side represent the connectors for each of the 8 daughter boards.

The daughter board schematic file details an example setup for thermocouple-based operation. There will be two such boards. Other daughter boards may be configured differently depending on the types of sensors but this has not been designed because it is for future expansion. In the schematic there are the connections on the right side that correspond directly to the connections to the main board. There are also 8 sensors on the left side that represent the thermocouple probes.

Enclosure

Step Two Step Three Step Four Step Five Step Six Step Seven Step Seven Step Seven Step Seven
Enclosure Laser Cut Drawing

Enclosure Laser Cut Drawing

Component with Link Print Quantity
Handle 1
Handle Holder 4
Box Side Hinge 2
Lid Side Hinge 2
Lid Side Latch 1
Box Side Latch 1
Latch Locking Pin 1
Latch Handle 1

Electrical Component Flowchart

There are three different stages in the final electrical component flowchart. All three different stages have multiple components attached. The first stage consists of the 'TC Probe', Multiplexer, Op-Amp and the ADC. This first stage will be represented as the ‘TC Array’. The second stage will be the ‘Control System’ and the last one would be the ‘Input/output’ stage.The design flowchart may be found here.
Data Flow

Data Flow

Test Plans

System Integration Test Plans:

Here is a link to our test plan for drilling through the insulation material used in the biogenic refinery. We want to confirm that we can drill a hole through the insulation without the material cracking to prevent any potential damage to the refinery system.

Refractory Material Duraboard Rockwool Insulation

Layers

Layers

Here is a link to our test plan for the thermocouple mount used inside the refinery carbonizer. This will test that the materials used can withstand the refinery environment as well as not interfere with the normal operation.

Electronics Test Plan:

Here is a link to our EE test plan for the installation and testing of K-type Thermocouples. These thermocouples would be installed at various places inside the refinery to ensure correct functionality(variation in output voltage with respect to temperature change) and also to ensure that K-type thermocouples would be suitable.

Electronics Bill Of Material

The final Electrical components were selected and are to be used for the Electronic Subsystem.

Final BOM

Final BOM

Risk Assessment

Updated FMEA for DDR

Updated FMEA for DDR

The updated FMEA as of 12/11/2018 can be found here.

Risk Index Vs Time till Systems Design

Risk Index Vs Time till Systems Design

As each phase went by, our risk index decreased

Accomplishments

System Integration

Electronic Subsystems

Future Tasks

Following are the tasks that are to be completed:

Plans for next phase

Gantt Chart for Next Phase

Gantt Chart for Next Phase

The entire updated copy of the Gantt Chart for MSDII can be found here.


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