Matt Switzer (ME) Tyler Josselyn (ME) Evan Hall (EE) Phil...
Transcript of Matt Switzer (ME) Tyler Josselyn (ME) Evan Hall (EE) Phil...
Matt Switzer (ME)
Tyler Josselyn (ME)
Evan Hall (EE)
Phil Floroff (EE)
Faculty Guide: Sarah Brownell Customer: Fermin Reyegadas, Fundacion Cantaro Azul
Overview • Project background
• Planning
• System design
• Testing
• Conclusions
• Recommendations
• Questions
Project Background
• Existing UV water treatment system
• Gravity fed
• Weak local power grid
• Objective:
– Detect failure & protect clean water
Customer Needs • Prevent contamination of clean
tank during given failure modes: -Power outage -Brownout -Blown UV bulb • Warn kiosk operator of failure • Allow for independent UV
chamber operation • Made from materials available
in Mexico • Require few consumable parts • Maintain 5 L/min flow rate per
chamber • Low cost solution
Engineering Specs
System Architecture
Control Board (PCB)
Irrigation Valve 1
Irrigation Valve 2
Water Flow Control
UV photodiode 1
UV photodiode 2
Failure Detection
Warning Speakers
LED System Indicators
Operator Interface
Valve Assembly
• Irrigation valves
• Solenoid/diaphragm
• Low flow, low pressure operation
• Fail Closed
• Easy integration
Dual irrigation valve assembly
Electronics
• The printed circuit board shown here controls the valves and warns the operator that there is a failure
• Requires some trained assembly (to be assembled by PCB assembly service)
Electronics Enclosure
• The PCB was designed to fit into a small conduit box that can be mounted in the kiosk, near the valves
• Speakers and LEDs are mounted externally on box
Photodiodes
• Capable of detecting all failure modes
• Design allows system prevents flow restart until safe level of UV output is reached
• No UV Chamber draining will be necessary
• Automatic restart after power loss
• Simple installation in chamber
Photodiode
UV Bulb
Warning the operator
• Failure – Speaker sounds and red LED lights, both powered by 9V battery
• To turn off the speaker and red LED, the operator can flip a switch
• Once the problem is fixed, a green LED will light, the switch is flipped back
• The system also includes an amber LED that turns on when the battery voltage is low
Speaker
System Ready Switch
Test Rig
• We built a test rig to simulate the gravity fed system in the actual kiosks
• The two irrigation valves run in parallel to two UV chambers
• We are able to simulate a power failure by pressing the red button seen to the left
Test Results
• Gravity fed system achieved a flow rate of 4.5 L/min
• Inlet/outlet height differential must be >4 ft.
• Circuit board closes valve when UV light is not present
• Speaker/LED gets attention of operator at > 8 meters
• Backup alarm/LED will run for 17 consecutive hours on one 9V battery
• Valves seep 15.5mL/hr average
Budget
MSD Costs Budgeted Actual
Test Stand (tanks, pump,
structure) $400 $184.39
Electrical (wire, circuits,
PCB) $100 $202.63
Plumbing (Pipe, flow stop
mechanism) $100 $63.10
Total $600 $450.12
Costs to Customer Quantity Total Price
Valves 2 $34.10
PCB 2 $66.00
Photodiodes 2 $44.88
LEDs 6 $1.96
Speakers 2 $4.58
Wiring As
Necessary ~$10.00
Assembly - Need Quote
Other Parts - $40.71
TOTAL per Kiosk $202.93
Conclusion: Successes • Independent chamber operation
– Using two independent circuits
• Under budget
• LEDs and speakers will get operator attention
• Valves stop water flow
• Auto-restart when safe UV output level sensed in chamber
Conclusion: Challenges • Valve leakage due to dirty diaphragm
• Mousetrap valve concept
• Getting system to work on one circuit
• Speakers not as loud as expected
• Couldn’t incorporate rapid power on-off delay • Deemed unnecessary
• Customer will not be able to fix electrical issues in field
• PCB assembly for customer
Recommendations
• 2 independent circuits
• Periodic diaphragm cleaning
• Test correlation between UV output and photodiode voltage
• Valves located close to UV chambers
• Upon install, ensure valve seals water flow
Questions?