P14417: B9 Plastics - Particle Filter Subsystem Design Dan Anderson / Thomas Heberle / Perry Hosmer / Karina Roundtree / Kelly Stover October 29, 2013
Customer Requirements Customer Category Importance Description Req. # 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 Number of Tools Required for Ease of Use 3 Easy to Clean/Recharge v Easy to prepare for use (dis)assembly by the end user - 2 1 Ease of Use 3 Lightweight for transport. Minimize weight of filter Weight in LBs v LBs (Pounds) 10 5 Time elapsed between beginning of pour and first water that enters the v Ease of Use 3 Has a minimal start-up period. Minimize start-up bucket s (seconds) 30 10 Operates using only energy available naturally Ease of Use 3 - Doesn't need power source Binary (Yes/No) - - No (gravity, human power, etc.) Economics 3 Filter is Inexpensive Minimize cost of filter Total cost to produce v $ (dollars) 25 20 Usable by a family of 5, for 2-5 years w/out full Economics 3 replacement Maximize durability of filter Mean Time To Failure ^ Number of Uses 730 3650 Requires no consumables for operation, except for Economics 9 very cheap & locally available materials (salt, soap, sand, etc.) Minimize cost to maintain Annual cost to operate v $ (dollars) 2 0 Removes Particles (turbidity/total suspended solids), v Functionality 9 improves UV TRANSMISSION Turbidity is decreased Percentage Decrease % >50% >75% Removes Particles (turbidity/total suspended solids), total suspended solids v Functionality 9 improves UV TRANSMISSION decreased Percentage Decrease % >50% >75% Removes Particles (turbidity/total suspended solids), remove particles larger than Functionality 9 improves UV TRANSMISSION 5 um Percentage Decrease v % >50% >75% Percent of people who say water - Functionality 3 Does not negatively affect the taste of the water No negative taste of water tastes the same or better % >50% >75% Doesn't produce hazardous - Safety 3 No hazardous releases release, no chemicals added Binary (Yes/No) - - No Functionality 3 Flowrate ^ lpm 0.0394 0.6309
Engineering Metrics & Specifications: Functional Decomposition: Customer Requirement Function Metrics Direction Units Marginal Target Test Plan Easy to prepare for *Items in Red are Metrics and Specs v Easy to Clean/Recharge use Time to clean Minutes 10 5 Test #1 that map to Customer Requirements Number of Tools Required or Risk Assessment Tasks Easy to Clean/Recharge Easy to prepare for for (dis)assembly by the v use end user - 2 1 Test #2 Clean / Minimize weight of v recharge filter Lightweight for transport. filter Weight in LBs LBs (Pounds) 10 5 Test #3 Time elapsed between beginning of pour and first water that enters the Collect Water v Has a minimal start-up period. Minimize start-up bucket s (seconds) 30 10 Test #4 Access Water (bucket) Operates using only energy available Doesn't need power naturally (gravity, human power, etc.) - source Binary (Yes/No) - - No Test #5 v Filter is Inexpensive Minimize cost of filter Total cost to produce $ (dollars) 25 20 Test #6 Generate Introduce different forces Usable by a family of 5, for 2-5 years Maximize durability water and filter ^ w/out full replacement of filter Mean Time To Failure Number of Uses 730 3650 Test #7 on the particles Filter and the water Requires no consumables for operation, Separate except for very cheap & locally available Minimize cost to v materials (salt, soap, sand, etc.) maintain Annual cost to operate $ (dollars) 2 0 Test #8 water and Convert energy particles Removes Particles (turbidity/total to work to suspended solids), improves UV separate v TRANSMISSION Turbidity is decreased Percentage Decrease % >50% >75% Test #9 Removes Particles (turbidity/total suspended solids), improves UV total suspended v TRANSMISSION solids decreased Percentage Decrease % >50% >75% Test #9 Isolate and Restrict contain filtered Removes Particles (turbidity/total contamination suspended solids), improves UV remove particles water v TRANSMISSION larger than 5 um Percentage Decrease % >50% >75% Test #9 Percent of people who say Does not negatively affect the taste of No negative taste of water tastes the same or - the water water better % >50% >75% Test #10 Doesn't produce hazardous release, no - No hazardous releases chemicals added Binary (Yes/No) - - No Test #11 Support World Health Org. Est. on Use needs for consumption Usable by a family of 5, for 2-5 years (equated to flow w/out full replacement rate); for 5 person ^ home for 2-5 years Flowrate lpm 0.0394 5 gal in .5hr
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. 5 th , hadn’t rained in a while, tested on Oct. 19 th . • Gen 2: Collected Oct. 18 th , moderate rain, tested on Oct. 19 th . • Gen 3: Collected Oct. 23 rd , frequent rain preceding days, test on Oct. 24 th . • 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. Water Testing Results Sample Average Turb (NTU) TSS (mg/L) Gen 1 1 534 Gen 2 14.8 596 Gen 3 32.4 520 Brewery 872 2343
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) o Cheap and easily adaptable o Not easy to clean effectively o • Plastic Mesh Cheaper o Not as small a mesh o Easily deformable o • Stainless Steel Mesh Small mesh size o Durable o
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 mesh 𝑏𝑚 o Flow = 1.34 𝑛𝑗𝑜∗𝑗𝑜^2 @ 1 psid (pressure difference) • Approximate diameter of S.S. mesh = 30 cm = 11.81 in 1.34 𝑏𝑚 3.785 𝑀 π 4 11.81 𝑗𝑜 2 o 𝑅 = 𝐺𝑚𝑝𝑥 ∗ 𝐵𝑠𝑓𝑏 = min∗𝑗𝑜 2 ∗ 1 𝑏𝑚 ∗ • Q @ 1 psid = 555.6 L/min
Flow Rate Considerations • Comparison and Conclusions: o ΔP, in this case = 1 psi = 6,895 Pa o 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 Δ P 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.
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