P14417: B9 Plastics - Particle FilterSubsystem Design

Dan Anderson / Thomas Heberle / Perry Hosmer / Karina Roundtree / Kelly Stover

October 29, 2013

Customer Requirements (On Edge)

Category Customer Req. # Importance Description

Ease of Use CR1 9 Easy to prepare for use

Ease of Use CR2 3 Lightweight for transport

Ease of Use CR3 3 Has a minimal start-up period

Ease of Use CR4 9 Operates using energy available naturally

Economics CR5 9 Filter is inexpensive

Economics CR6 9 Usable by a family of 5, for 2-5 years w/out full replacement

Economics CR7 9 Requires no consumables for operation, except cheap & locally available materials

Functionality CR8 9 Improves UV transmission

Functionality CR9 9 Decreases turbidity

Functionality CR10 9 Decreases total suspended solids

Functionality CR11 3 Does not negatively affect the taste of the water

Safety CR12 9 Does not negatively affect the safety of drinking water

Functionality CR13 3 Filters enough water for a family of 5

Engineering Requirements (On Edge)Category Importance Customer Requirement Function Metrics Direction Units Marginal TargetEase of Use 3 Easy to Clean/Recharge Easy to prepare for use Time to clean v Minutes 10 5

Ease of Use 3 Easy to Clean/Recharge Easy to prepare for useNumber of Tools Required for (dis)assembly by the end user v - 2 1

Ease of Use 3 Lightweight for transport. Minimize weight of filter Weight in LBs v LBs (Pounds) 10 5

Ease of Use 3 Has a minimal start-up period. Minimize start-up

Time elapsed between beginning of pour and first water that enters the bucket v s (seconds) 30 10

Ease of Use 3 Operates using only energy available naturally (gravity, human power, etc.) Doesn't need power source Binary (Yes/No) - - - No

Economics 3 Filter is Inexpensive Minimize cost of filter Total cost to produce v $ (dollars) 25 20

Economics 3Usable by a family of 5, for 2-5 years w/out full replacement Maximize durability of filter Mean Time To Failure ^ Number of Uses 730 3650

Economics 9Requires no consumables for operation, except for very cheap & locally available materials (salt, soap, sand, etc.) Minimize cost to maintain Annual cost to operate v $ (dollars) 2 0

Functionality 9Removes Particles (turbidity/total suspended solids), improves UV TRANSMISSION Turbidity is decreased Percentage Decrease v % >50% >75%

Functionality 9Removes Particles (turbidity/total suspended solids), improves UV TRANSMISSION

total suspended solids decreased Percentage Decrease v % >50% >75%

Functionality 9Removes Particles (turbidity/total suspended solids), improves UV TRANSMISSION

remove particles larger than 5 um Percentage Decrease v % >50% >75%

Functionality 3 Does not negatively affect the taste of the water No negative taste of waterPercent of people who say water tastes the same or better - % >50% >75%

Safety 3 No hazardous releasesDoesn't produce hazardous release, no chemicals added Binary (Yes/No) - - - No

Functionality 3 Flowrate ^ lpm 0.0394 0.6309

Filter

Clean / recharge filter

Access Water Collect Water (bucket)

Introduce water and filter

Separate water and particles

Generate different forces on the particles and the water

Convert energy to work to separate

Isolate and contain filtered

water

Restrict contamination

Engineering Metrics & Specifications:Functional

Decomposition: Customer Requirement Function Metrics Direction Units Marginal Target Test Plan

Easy to Clean/RechargeEasy to prepare for use Time to clean v Minutes 10 5 Test #1

Easy to Clean/Recharge Easy to prepare for use

Number of Tools Required for (dis)assembly by the end user v - 2 1 Test #2

Lightweight for transport.Minimize weight of filter Weight in LBs v LBs (Pounds) 10 5 Test #3

Has a minimal start-up period. Minimize start-up

Time elapsed between beginning of pour and first water that enters the bucket v s (seconds) 30 10 Test #4

Operates using only energy available naturally (gravity, human power, etc.) Doesn't need power

source Binary (Yes/No) - - - No Test #5Filter is Inexpensive Minimize cost of filter Total cost to produce v $ (dollars) 25 20 Test #6

Usable by a family of 5, for 2-5 years w/out full replacement

Maximize durability of filter Mean Time To Failure ^ Number of Uses 730 3650 Test #7

Requires no consumables for operation, except for very cheap & locally available materials (salt, soap, sand, etc.)

Minimize cost to maintain Annual cost to operate v $ (dollars) 2 0 Test #8

Removes Particles (turbidity/total suspended solids), improves UV TRANSMISSION Turbidity is decreased Percentage Decrease v % >50% >75% Test #9

Removes Particles (turbidity/total suspended solids), improves UV TRANSMISSION

total suspended solids decreased Percentage Decrease v % >50% >75% Test #9

Removes Particles (turbidity/total suspended solids), improves UV TRANSMISSION

remove particles larger than 5 um Percentage Decrease v % >50% >75% Test #9

Does not negatively affect the taste of the water

No negative taste of water

Percent of people who say water tastes the same or better - % >50% >75% Test #10

No hazardous releases

Doesn't produce hazardous release, no chemicals added Binary (Yes/No) - - - No Test #11

Usable by a family of 5, for 2-5 years w/out full replacement

Support World Health Org. Est. on Use needs for consumption (equated to flow rate); for 5 person home for 2-5 years Flowrate ^ lpm 0.0394 5 gal in .5hr

*Items in Red are Metrics and Specs that map to Customer Requirements or Risk Assessment Tasks

Filter Assembly

Filter Assembly

Water Characterization

• Key metrics for consideration:o Turbidity: “cloudiness or haziness of a fluid caused by

individual particles, normally invisible to the naked eye.”o Total Suspended Solids: measurement of water quality, dry

weight of particles that would be trapped by a filter.

• Water source used: Genesee River Watero Represents possible use conditions in the developing world.o Used as litmus test for Better Water Maker to determine

process improvement.

Water Characterization

• Resource contacted: Dr. Scott Wolcott (RIT Professor)

• Testing: Several samples were taken from the Genesee during varying conditions that could affect turbidity and TSS.

• Three samples collected and tested. o Gen 1: Collected Oct. 5th, hadn’t rained in a while, tested on

Oct. 19th.o Gen 2: Collected Oct. 18th, moderate rain, tested on Oct. 19th.o Gen 3: Collected Oct. 23rd, frequent rain preceding days, test on

Oct. 24th.o Also considered brewery waste water provided by Dr. Wolcott in

analysis.

Water Characterization

Water Characterization

Water Characterization

• Possible sources of error: time between insertion/removal from oven, minor spillage, etc.

SampleGen 1Gen 2Gen 3Brewery 2343872

114.832.4

534

520596

TSS (mg/L)Water Testing Results

Average Turb (NTU)

Identification of Critical Subsystems

• Mesh • Fasteners• Seal• Sandwich Assembly• Outer Walls

Component FeasibilityMesh

Materials

• Cheese Clotho #90 grade(44 x 36 Vertical x Horizontal threads per inch)o Cheap and easily adaptableo Not easy to clean effectively

• Plastic Mesho Cheaper o Not as small a mesho Easily deformable

• Stainless Steel Mesho Small mesh sizeo Durable

Stainless Steel

• Stainless steel is in a family of alloy steels containing a minimum of 10.5% chromium. All stainless steels have a higher resistance to corrosion than their mild steel counterparts.

• This resistance to attack is due to the naturally occurring chromium-rich oxide film formed on the surface of the steel.

• The film is rapidly self-repairing in the presence of oxygen. Damage by abrasion, cutting or machining is quickly repaired.

Flow Rate Considerations

• Specification from supplier for 5 micron stainless steel mesho Flow = @ 1 psid (pressure difference)

• Approximate diameter of S.S. mesh = 30 cm = 11.81 ino

• Q @ 1 psid = 555.6 L/min

Flow Rate Considerations

• Comparison and Conclusions:o ΔP, in this case = 1 psi = 6,895 Pao Based on new specification for flow rate (Q= 0.394 L/min), we

would achieve 14,102 times the marginal flow rate value.• It can be concluded that using 5 micron steel mesh

is a good course of action to reach desired flow rate.o Max ΔP in our case is approximately 2,632 Pa

• Assumes max possible volume in upper bucket = 5 gallons

• Using approximate dimensions for the filter assembly (i.e. D = 30 cm)

Flow Rate Considerations

Flow Rate Considerations

• Max possible pressure = 2,620 Pa, about 2.6 times less than the pressure difference used in the S.S. specification.

• Pressure is a function of open area available (diminishes through clogging of filter) and weight of water above filter.

• Difficult to determine a mathematical model since there is some inherent variable in the water properties.

Test Plan: Flow Rate

• Use available “pond pump” to generate a steady flow of a known rate over a simple filter mesh assembly at Genesee River.

• Determine based on rate of pump output, how long it will take to introduce five gallons of water to assembly.

• Determine adequacy of five micron Stainless Steel mesh.

• Introduce filter complexity to improve process.

Stress Testing

Fw=pVg=185.7NFs=pVg=1826.5NPmesh=(Fw+Fs)/Amesh=48.83kPa

Stress Modeling - Von Mises

Stress Testing - Displacement

Stress Modeling - Factor Safety

Cleaning

• Cleanliness is essential for maximum resistance to corrosion.

• Never use abrasive powders or materials on stainless.

• Always use a soft cloth. • Mild detergents and soap can be used but those

containing chloride detergents should be avoided.

Risks

• Bacteria forming on sando Rapid sand filtration - 20m/hour

Chemically pre-treatedo Slow sand filtration - 0.4m/hour

Just scrape off the biofilm on sand surface

Component FeasibilitySeal

Seal Considerations

• Type of seal application:o Low temperature – T max = 120ᵒ F o Low pressure: W water, max = 185 N = 41.6 lb

• Need two seals for top and bottom of sandwich assembly

• Desire low compressibility

• Supplier Contacted:

Seal Considerations

• Determination: Rubber Gasket application

• Example:

Seal Considerations

• Specifications: o Max Temp. = 200 F o Max. Pressure = 250 psi = 1.724 MPa

• Supplier will give us free gaskets upon completion of detailed design drawings, cut to our specification.

Seal Considerations: Test Plan

• Use standard gasket “sealability” test: ASTM F37 -06

• Testing capabilities available through Garlock

Component FeasibilityOther Key Components

FastenersFastener Choice is dependent on the design requirements and the environment in which the fastener will be used.

• Threaded vs. Non-Threadedo Non-threaded is not ideal for continuous dis and reassemblyo Threaded fasteners provide ease of assembly and reusability without much

wear.

• Two main threaded fasteners:o Nuts & Boltso Screws

*** Although this may not be necessary if captive or welded nuts can be used.

Fastener Materials with high resistance to weather and/or corrosion:

• Stainless Steel • Titanium• Brass• Bronze

Of these four materials, Titanium is the most lightweight. But considering the costs of each, stainless steel is the most feasible material to use in our Filter.Summary: We should use stainless steel bolts with wing nuts. The wing nuts allow for tool-less dis and re-assembly, which is a great convenience in our application.

Water Usage

Average of 2.6 liters / day / person needed

Therefore a family of 5 needs 13 liters or 3.4 gallons / day

Lifting Task

Used NIOSH Lifting Equation to evaluate the feasibility of the task

Assumption made on height of mediaRecommended Weight Limit: 33.5 lbs3.4 Gallons of Water ~ 28.4 lbs5 Gallons of Water ~ 41.7 lbs**Lifting Index: 1.25, slight risk for low-back pain or

injury

Preliminary Bill of Materials

Qty Item Price per unit Price per 1000 units Comments2 Bucket lids (UN plain lid) 2.94 29402 Buckets (5 gal Plastic UN rated Pail) 5.94 59404 Bolts 0.76 7544 Wing Nuts 0.42 4124 Washers 0.07 701 Wall for sandwhich (2” tall 10” schedule 80 PVC) 3.95 39501 coarse mesh (100 micron stainless steel) na na last group estimated 2.5 per unit1 fine mesh (5 micron stainless steel) na na last group estimated 2.5 per unit2 Rubber gaskets na na last group estimated 2 per unit

Engineering Requirements: Test Plan (On Edge)

Category Importance Customer Requirement Function Metrics Direction Units Marginal TargetEase of Use 3 Easy to Clean/Recharge Easy to prepare for use Time to clean v Minutes 10 5

Ease of Use 3 Easy to Clean/Recharge Easy to prepare for useNumber of Tools Required for (dis)assembly by the end user v - 2 1

Ease of Use 3 Lightweight for transport. Minimize weight of filter Weight in LBs v LBs (Pounds) 10 5

Ease of Use 3 Has a minimal start-up period. Minimize start-up

Time elapsed between beginning of pour and first water that enters the bucket v s (seconds) 30 10

Ease of Use 3 Operates using only energy available naturally (gravity, human power, etc.) Doesn't need power source Binary (Yes/No) - - - No

Economics 3 Filter is Inexpensive Minimize cost of filter Total cost to produce v $ (dollars) 25 20

Economics 3Usable by a family of 5, for 2-5 years w/out full replacement Maximize durability of filter Mean Time To Failure ^ Number of Uses 730 3650

Economics 9Requires no consumables for operation, except for very cheap & locally available materials (salt, soap, sand, etc.) Minimize cost to maintain Annual cost to operate v $ (dollars) 2 0

Functionality 9Removes Particles (turbidity/total suspended solids), improves UV TRANSMISSION Turbidity is decreased Percentage Decrease v % >50% >75%

Functionality 9Removes Particles (turbidity/total suspended solids), improves UV TRANSMISSION

total suspended solids decreased Percentage Decrease v % >50% >75%

Functionality 9Removes Particles (turbidity/total suspended solids), improves UV TRANSMISSION

remove particles larger than 5 um Percentage Decrease v % >50% >75%

Functionality 3 Does not negatively affect the taste of the water No negative taste of waterPercent of people who say water tastes the same or better - % >50% >75%

Safety 3 No hazardous releasesDoesn't produce hazardous release, no chemicals added Binary (Yes/No) - - - No

Functionality 3 Flowrate ^ lpm 0.0394 0.6309

Risk Assessment (On Edge)ID Risk Item Importance Action to Minimize Risk Owner Date Opened Date Closed (or expected)

  Describe the risk briefly L*SWhat actions will you take (and by when) to prevent, reduce the impact of, or transfer the risk of this occuring

Who will ensure that this risk is fully mitigated?    

1 Cleaning is difficult 9Supply cleaning instruction, minimize number of parts, minimize disassembly/assembly time, mistake proof up/down directions Tom 9/17/2013 2/14/2014

2 Costs more than $25/unit 9Design to be low cost Kelly 9/17/2013 11/28/20133 Stress concentration 6Spread load out around edge of filter Perry 9/17/2013 11/21/20134   6Calculate necessary force rating Perry 9/17/2013 11/21/2013

5 Flow rate is too slow 6Increase surface area of filter, find more porous materials, define minimum flow rate to test against (use scenario) Test Plan Perry 10/1/2013 11/7/2013

6 Sand may corrode steel 6Pack sand tightly, select different material for medium Karina 10/22/2013 10/31/2013

7 Filter fails "warm-up" time test 6 Introduce an additional mesh screen Tom 10/24/2013 4/7/2014

8 User not detecting tear in filter 4No hidden filter, instruct user to inspect both sides of "sandwich" Dan 10/1/2013 10/8/2013

9 Bacteria may build up in filter 4Chemically treat sand to prevent material build up. Select different material for medium Karina 10/10/2013 10/31/2013

10 Corrosion 3Use materials which won't corrode, provided clear cleaning instruction Karina 9/17/2013 10/16/2013

11 Weight is too much 3Ergonomic study, design to allow women and children to use Kelly 9/17/2013 10/21/2013

12Incorrect usage, sandwich inserted upside-down 3Use visuals whenever possible, minimize text, poka-yoke Dan 10/3/2013 12/5/2013

13 Stability issues with bucket 2Design proper attachments, make sure surface is level prior to use, worse case - will the bucket withstand that? Dan 9/17/2013 11/26/2013

14Filter introduces bad taste to water 2Use non corrosive materials Perry 10/24/2013 3/7/2014

15 Leakage 1Use rubber gasket, clamped down tightly Perry 9/17/2013 11/19/2013

16 Filter may be too tall 1Calculate necessary height ASAP, test for fill amount Kelly 9/17/2013 10/1/2013

Risk Growth

6/25/2013 8/14/2013 10/3/2013 11/22/2013 1/11/2014 3/2/2014 4/21/2014 6/10/2014 7/30/20140

2

4

6

8

10

12

14

Risk CurvePolynomial (Risk Curve)

Project Plan

Detailed Design: Diagram of Activities

Component Selection

Make/Buy Decisions

Part Drawings

Assembly Drawings

Complete Bill of Materials

Risk Assessment (Detailed Design)

Engineering Analysis

Simulation Models

Input from Eng. Analysis & Research.Demonstrate the more experimental and/or derived metrics and specs.

Proof of Concept

Test PlanDevelop Assembly Process Detail test

procedures to be executed in MSD 2: Build & Test.

• Hardware Design• Complete

Drawing Package• Assembly Process• Bill of Materials• Budget Overview• Risk Assessment• Testing Plan (for

MSD 2)

Budget Review of BOM

Detailed Design

Demonstrate feasibility and meeting specifications

Design for manufacturability, cost, & repeatability (assembler perspective).

Ensure the proposed design can be completed with the Budget constraint.

Questions