P14417: B9 Plastics - Particle Filter Subsystem Design Dan - - PowerPoint PPT Presentation

P14417: B9 Plastics - Particle Filter

Subsystem Design

Dan Anderson / Thomas Heberle / Perry Hosmer / Karina Roundtree / Kelly Stover October 29, 2013

Customer Requirements

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

Category Importance Customer Requirement Function Metrics Direction Units Marginal Target Ease 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 use Number 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 3 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 Economics 9 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 Functionality 9 Removes Particles (turbidity/total suspended solids), improves UV TRANSMISSION Turbidity is decreased Percentage Decrease

v

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

v

% >50% >75% Functionality 9 Removes 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 water Percent of people who say water tastes the same or better

• %

>50% >75% Safety 3 No hazardous releases Doesn'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

• n 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/Recharge Easy 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 #5 Filter 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

• f 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

• r Risk Assessment Tasks

Filter Assembly

Filter Assembly

Water Characterization

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

normally invisible to the naked eye.”

• Total Suspended Solids: measurement of water quality, dry weight of

particles that would be trapped by a filter.

• Water source used: Genesee River Water
• Represents possible use conditions in the developing world.
• 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.
• Gen 1: Collected Oct. 5th, hadn’t rained in a while, tested on Oct. 19th.
• Gen 2: Collected Oct. 18th, moderate rain, tested on Oct. 19th.
• Gen 3: Collected Oct. 23rd, frequent rain preceding days, test on Oct. 24th.
• 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
• ven, minor spillage, etc.

Sample Gen 1 Gen 2 Gen 3 Brewery 2343 872 1 14.8 32.4 534 520 596 TSS (mg/L) Water Testing Results Average Turb (NTU)

Identification of Critical Subsystems

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

Component Feasibility Mesh

Materials

• Cheese Cloth
• #90 grade(44 x 36 Vertical x Horizontal threads per inch)
• Cheap and easily adaptable
• Not easy to clean effectively
• Plastic Mesh
• Cheaper
• Not as small a mesh
• Easily deformable
• Stainless Steel Mesh
• Small mesh size
• 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
• xide 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 mesh
• Flow = 1.34

𝑕𝑏𝑚 𝑛𝑗𝑜∗𝑗𝑜^2 @ 1 psid (pressure difference)

• Approximate diameter of S.S. mesh = 30 cm = 11.81 in
• 𝑅 = 𝐺𝑚𝑝𝑥 ∗ 𝐵𝑠𝑓𝑏 =

1.34 𝑕𝑏𝑚 min∗𝑗𝑜2 ∗ 3.785 𝑀 1 𝑕𝑏𝑚 ∗ π 4 11.81 𝑗𝑜 2

• Q @ 1 psid = 555.6 L/min

Flow Rate Considerations

• Comparison and Conclusions:
• ΔP, in this case = 1 psi = 6,895 Pa
• 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.

• 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
• ver 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=185.7N Fs=pVg=1826.5N Pmesh=(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 sand
• Rapid sand filtration - 20m/hour
• Chemically pre-treated
• Slow sand filtration - 0.4m/hour
• Just scrape off the biofilm on sand surface

Component Feasibility Seal

Seal Considerations

• Type of seal application:
• Low temperature – T max = 120ᵒ F
• 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:
• Max Temp. = 200 F
• 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 Feasibility Other Key Components

Fasteners

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

• Threaded vs. Non-Threaded
• Non-threaded is not ideal for continuous dis and reassembly
• Threaded fasteners provide ease of assembly and reusability without much wear.
• Two main threaded fasteners:
• Nuts & Bolts
• Screws

Screws Pros Cons · Can normally be removed and reinserted without reducing their effectiveness · Does not require access to both sides

• f

assembly · Relatively Low-cost

• ·

Higher wear

• n

the mating surfaces with re-and dis-assembly · Wear

• n

mating device threads (screw) · Wear

• n

mating recipient (threads created by screw’s threads) · Possibility

• f

wear

• n

screw head (stripping)

• Nuts

& Bolts Pros Cons · Easily be removed and reinserted without reducing their effectiveness · Minimal wear

• n

bolt head (dependent mostly

• n

proper use) · Very minimal wear

• n

mating

• ·

Requires access to both sides

• f

component during assembly (generally)*** · Relatively high-cost

• *** 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

• ur 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 media Recommended Weight Limit: 33.5 lbs 3.4 Gallons of Water ~ 28.4 lbs 5 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 Comments 2 Bucket lids (UN plain lid) 2.94 2940 2 Buckets (5 gal Plastic UN rated Pail) 5.94 5940 4 Bolts 0.76 754 4 Wing Nuts 0.42 412 4 Washers 0.07 70 1 Wall for sandwhich (2” tall 10” schedule 80 PVC) 3.95 3950 1 coarse mesh (100 micron stainless steel) na na last group estimated 2.5 per unit 1 fine mesh (5 micron stainless steel) na na last group estimated 2.5 per unit 2 Rubber gaskets na na last group estimated 2 per unit

Engineering Requirements: Test Plan

Category Importance Customer Requirement Function Metrics Direction Units Marginal Target Ease 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 use Number 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 3 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 Economics 9 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 Functionality 9 Removes Particles (turbidity/total suspended solids), improves UV TRANSMISSION Turbidity is decreased Percentage Decrease

v

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

v

% >50% >75% Functionality 9 Removes 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 water Percent of people who say water tastes the same or better

• %

>50% >75% Safety 3 No hazardous releases Doesn't produce hazardous release, no chemicals added Binary (Yes/No)

• No

Functionality 3 Flowrate

^

lpm 0.0394 0.6309

Risk Assessment

ID Risk Item Importance Action to Minimize Risk Owner Date Opened Date Closed (or expected) Describe the risk briefly L*S What 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 9 Supply 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 9 Design to be low cost Kelly 9/17/2013 11/28/2013 3 Stress concentration 6 Spread load out around edge of filter Perry 9/17/2013 11/21/2013 4 6 Calculate necessary force rating Perry 9/17/2013 11/21/2013 5 Flow rate is too slow 6 Increase 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 6 Pack 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 4 No hidden filter, instruct user to inspect both sides of "sandwich" Dan 10/1/2013 10/8/2013 9 Bacteria may build up in filter 4 Chemically treat sand to prevent material build up. Select different material for medium Karina 10/10/2013 10/31/2013 10 Corrosion 3 Use materials which won't corrode, provided clear cleaning instruction Karina 9/17/2013 10/16/2013 11 Weight is too much 3 Ergonomic study, design to allow women and children to use Kelly 9/17/2013 10/21/2013 12 Incorrect usage, sandwich inserted upside-down 3 Use visuals whenever possible, minimize text, poka-yoke Dan 10/3/2013 12/5/2013 13 Stability issues with bucket 2 Design proper attachments, make sure surface is level prior to use, worse case - will the bucket withstand that? Dan 9/17/2013 11/26/2013 14 Filter introduces bad taste to water 2 Use non corrosive materials Perry 10/24/2013 3/7/2014 15 Leakage 1 Use rubber gasket, clamped down tightly Perry 9/17/2013 11/19/2013 16 Filter may be too tall 1 Calculate necessary height ASAP, test for fill amount Kelly 9/17/2013 10/1/2013

Risk Growth

2 4 6 8 10 12 14 6/25/2013 8/14/2013 10/3/2013 11/22/2013 1/11/2014 3/2/2014 4/21/2014 6/10/2014 7/30/2014 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 Plan Develop 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