East Hill SurfersEast Hill SurfersFlow Control DeviceFlow Control Device

Elegant . . .Elegant . . .

Reliable . . .Reliable . . .

Precise . . .Precise . . .

And DEAD SEXY.And DEAD SEXY.

DeveloDeveloppiningg The Desi The Desiggnn

Define CriteriaDefine Criteria

Generate ChoicesGenerate Choices

Pick it outPick it out

FCD CriteriaFCD Criteria

Clogging ResistanceClogging Resistance

SizeSize

ReliabilityReliability

CostCost

Ease of Use / MaintenanceEase of Use / Maintenance

UniversalityUniversality

Variable Torque BucketVariable Torque Bucket

Floating InletFloating Inlet

Air InletAir Inlet

Prime DesiPrime Desiggn Choicesn Choices

Toilet FloatToilet Float

Plug FloatPlug Float

Device Decision MatrixDevice Decision Matrix

Device

Floating Inlet

Self-adjusting inlet height

Eliminates majority of head

variationB A B C C B Limited by small-pipe flow B+

Variable Torque Pulley

Open-Channel Flow

Feasible but ill-suited to low flow

B C C A C COverly complex and highly

prone to failureC

Spring-Supported

Bucket

Self-adjusting inlet height

Limited by small-pipe flow

A B B B A BHigh-wear gaskets prone to

frequent failureB

Pinhole Air Inlet

Partial vacuum inside tank

Likely success but requires

minute outletB A A C B B

Requires precision valve;Could be coupled with

Marriot TubeB

Toilet Float Valve

Intermediate tank with auto-feedback

inletLikely success A C B A A A

Very easy to obtain parts; Limited by size of unit

B+

Plugging Float Valve

Intermediate tank with auto-feedback

inlet

Likely success with precise components

A A A B B ABenefits of toilet valve yet

compact A

Stand-Alone Drip

Valve

NoneHead is Variable

Generates inconsistent flow

Control Device to verify FCD necessity

-n/a

Conventional Toilet Lever Valve Conventional Toilet Lever Valve SchematicSchematic

Inlet FlowF = A γh

L1

L2

Float

Buoyant Force = FB

Pin

•Calculations showed that a lever was excessive for Calculations showed that a lever was excessive for given design parametersgiven design parameters

•A simple float could control the low flow rates without a A simple float could control the low flow rates without a lever arm to amplify the magnitudelever arm to amplify the magnitude

Simple FloatSimple Float

Valve FCDValve FCD8.3 cm

11.0 cm

0.5 cm

4.4 cm

6.5 cm

2 mm

2.3 cm

9.1 cm

2 mm

5.6 cm

1.5 cm

2 cm

5.2 cm Housing Dimensions:ID = 7.85 cmOD = 8.8 cm

Float mass:6 grams

IV roller clamp

Rubber tip

Barb tubing adapter

PVCstem

IV tubing (~10 drops/mL)

Testing ApparatusTesting Apparatus

Assembled Prototype Testing Apparatus

Testing Testing ApparatusApparatus

FCD

Water Column

Manual Valve

7 kPa Pressure Senor – Logs readings to Easy Data

FCD PerformanceFCD Performance

y = -0.0004x + 0.4548

R2 = 0.9545

y = 5E-06x + 0.1645

R2 = 0.067

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

0.5

0 50 100 150 200 250 300 350 400 450

Time (seconds)

Q (

mL

/s)

Without FCD

With FCD

Clogging ExperimentClogging Experiment

Process Controller used to meter water Process Controller used to meter water into 10 cm tube. Refilled after head into 10 cm tube. Refilled after head dropped by 40 cm.dropped by 40 cm.

Interested in flow rate changes for each 40 Interested in flow rate changes for each 40 cm head drop as well as over several cm head drop as well as over several days. days.

Clogging DataClogging Data

0

5

10

15

20

25

30

35

40

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

Time (Days)

Hea

d (

cm)

What We LearnedWhat We Learned

Low flow presents lots of problemsLow flow presents lots of problems Complex and simple designs often do the Complex and simple designs often do the

same jobsame job It is easy to overlook valuable solutionsIt is easy to overlook valuable solutions A simple device can have vast implications A simple device can have vast implications

in the developing worldin the developing world

Further ResearchFurther Research

Is there a manufactured device like this Is there a manufactured device like this already out there? Cost comparisonalready out there? Cost comparison

Cleaning mechanismsCleaning mechanisms Manufacturing Costs and OpportunitiesManufacturing Costs and Opportunities Material SelectionMaterial Selection Maximum head capabilities - SizingMaximum head capabilities - Sizing

Steve Achieves Inner Constant FlowSteve Achieves Inner Constant Flow