156B Week 6

Overview of Status of Analysis, Design, Fabrication, Tests, etc.

• • Heating

    • Tests with 300W immersion heater in brewing container show that secondary heating is necessary to keep water at 95 degrees C

      • Immersion heater is not a viable option for final product because it overheats and the plastic of the body melts

      • Need to find alternative secondary heater

      • Additional preheating does not help the final temperature

    • Need to replace off-the-shelf plastic brewing container with a metal container, because plastic container is made of ABS and has a melting point of 105 degrees C, which is too low to be safe in our use

    • Use solenoid to control coffee machine water spout to preheat the water

    • May need to find a way to let water and tea mix better

  • Gate Valve

    • Going to use a stepper motor connected to the outside of the valve to open and close the valve and dispense tea

    • Working with a ChaiBrew electrical engineer to develop control systems for this

  • Magnetic Stirring

    • Using a magnetic stirring system similar to that in Nespresso milk frothing machines, where a motor connected to a magnet drives a second magnet in the kettle, rotating and stirring the milk to prevent it from boiling over, and also mixing the tea once it drops into the kettle

    • Replacing the hot plate under the kettle with a non-metallic plate to avoid the stirrer sticking to the bottom of the kettle without moving

Accomplishments from Previous Week

• • Eliminated immersion heater as a potential solution

  • Eliminated plastic brewing container as a potential solution

  • Disassembled hot plate from coffee machine frame, replacing it with non-magnetic plate

  • Tested magnetic stirring in boiling milk with different covers

Goals for Next Week (list names after each item). Use specific and measurable objectives.

• • Find and order metal brewing container & insulation - Soo

  • Find and order secondary heating system - Arun

  • Cut out the non-magnetic heating plate and integrate the magnetic stirrer motor to the bottom of the machine- Ian

  • Integrate gate valve controls - Shahin

Sponsor Comments from Last Meeting and Actions Taken to Address these Comments (indicate date of comments and if via email or in person)

• • Increase water:milk ratio from 2:1 to 4:1 (via Whatsapp 02/08/2016)

Instructor Comments from Last Meeting and Actions Taken to Address these Comments  (indicate date of comments and if via email or in person)

• • Looking into AC relays (AC and DC power issue because we'll be running arduino)

Comments from Other Students in the Class (indicate date of comments and if via email or in person)

Risks and Areas of Concern

Resources or Information Required but not Available

Schedule

• • Need to find a secondary heating element that will work (only tested with immersion heater)

  • finding parts that will fit in a normal coffee heater but also fit our criteria

Budget (list amount spent and amount remaining)

• • $250 spent, $750 remaining

Progress on Report and Webpage

• • Rough draft of report complete

  • Website is updated per last week's requirements