Historic, Archive Document

Historic,

Archive

Document

Do

not

assume

content

reflects

current

.

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NEINF-39-81

Steps

To

Savings

How

to Build

Your

Own

Slide

Presentation

1. Title slide.

2. Early

maple

syrupmakers used whatever techniques

were

available toboilsap,withlittleconcernfor efficiencyorcost. Indianspoured sapintohollow

tree trunks,

and

boiled itwith heatedstones, 3. while the colonistsusedironorcopperkettles fired

with

wood.

4. Next

came

ironpans,

5. followed bytoday'sevaporator.

6.

The

evaporatorsystemsavailabletodaydifferlittle

fromeachother.

7. Their

economic

efficiency

depends

mainlyonthe

availability,thermal characteristics,

and

costofthe

chosen

fuel.

8. Yet a

more

efficientevaporator

would

give

maple

syrupproducersa

much-needed

boostinthefaceof

fluctuating

demand

and

rising fuelcosts.

9.

The development

thatcurrentlyoffersthe

most

promiseforincreasingevaporatorefficiencyisthe heat

exchanger

or preheater.

10. Inthisenergy-savingsystem,steam fromthe

evaporatingsapisusedtoheatincomingsap,which

passes through pipeson its

way

tothesappan.

11.

A

preheatercan be

added

toanexisting evaporator

fora smallinitialcost.

12.

The

quality ofthesyrupwill notbeaffected,and processingwillcostless

because

lessenergywillbe

lost.

A

preheater increases the hourly evaporation

SERIES

FLOW

13

Jglllll

PARALLEL

FLOW

ijjliiii^^

13.

A

preheatercan be designedwitheitherseriesor

parallelflow. Inaseriesdesign,suchas the

one

developed by

George

Raithbyatthe Universityof

WaterlooinOntario,sapflowsthroughacontinuous

pipearrangedinabundleover thesappan.Inthe

paralleldesigndeveloped by

Howard Duchacek

at

the Universityof

Vermont

incooperationwiththe

ForestService,sapflowssimultaneously througha

single layer oftubesconnected bymanifoldsat

eachend.

14. Experiments have

shown

thatseries

and

parallel

flowdesignsresultinthe

same

increasein

evapor-ator efficiency. However, advantagesoftheparallel

designarethatitiseasiertomake,especiallybya

sugar maker;isflexibleenoughtofit

underthemany

typesofsteam

hoods

alreadyinplace;and hasa

lowersapfeedheadrequirement.

15.

A

parallelflow preheateriseasilyconstructed.

16.

To

buildyour own,startby determiningthehourly

sapflowthrough yourevaporator.

You

can

measure

17. orapplyarule ofthumb. Forexample,ifyouburnoil,

you

canestimatesapflowbymultiplying 10 times

the

number

ofgallonsofoilyou burnper hour.

18.

Or you

canmultiplythesquare

footageofyourevap-oratorby

two

toobtain a conservative estimateof

sapflow.

To

besure the preheaterislargeenough,

increasethisfigureby 20percent.

19.

The

tablefoundin ForestServiceresearchpaper

NE-388

givesthedimensionsfordesignelementsin the preheater,basedontherate ofsapflow. Let's

lookat

one

example. Ifsapflowis50gallonsper hour,

we

would

use 20feetof3/4-inchcoppertubing.

20. Manifolds

would

be1-1/4 inchesindiameter.

A

single

bank

of sixtubes,each 1-3/4inchesapart,

would

total 40inchesin length.

21.

The

inlet

and

outletfromthemanifold

would

be

1 inch indiameter.

The

diameterofthesteam

hood

stack

would

be6 inches,

and

thefeedtankheadat

least 1.2feet.

These

dimensionsare

minimum

values

and

slightdeviationswilloccur.

The

critical

factoristhe lengthofthe tubing, or

more

properly,

thesurfacearea.

Use

the

recommended

total

lengthtogetthe

maximum

potentialfrom your

preheater.

23. adrippan,

25. Beforeyoubegin actual construction,determine

26.

and

depthofthebackpan.

27.

Measure

theheightofthesaptankoutlet, 28. andtheexpected heightofthesapinletonthe

preheater.

The

differenceinheightshouldequal or

exceedthe mininrium head requiredbythetable.

29.

To

construct the preheater,you'llneedatorch,

lighter,50/50solder,solderflux,coppertubing

cutter,tapemeasure,hacksaw,screwdriver,

wrenches,electricdrill

and

bits,

and

steelwool.

We

hadthedrippan

made

inasheet metal shop,

and

usedaholecutter,tinsnipsandasaber

saw

with a

metal cuttingbladetomodifytheexistingsteam

hood.

30.

The

easiest-to-constructmanifoldcallsforcopper

tees

and

shortconnectingtubes.Inthiscase

we

used 1X 3/4-inch tees with 1x 3/4-jnch

elbows on

theends.

Two

1x 1-inchteesformtheinletandoutlet

nearthemiddleofthe manifold.

31.

To

begin, cut short sectionsofpipetofitbetween the teefittings..

32.

33. Cleanthesesections,andallparts tobesoldered, withsteelwooltoinsure a

good

sweatjoint.

34. Applyfluxtothemanifold pieces

and assemble

them.

35. Cutfive40-inch sectionsof3/4-inchtubing

and

one

40-inch sectionof1-inch tubing.

The

1-inchtubing

willservetwofunctions:assapinlettothe manifold,

36.

Assemble

thefive3/4-inchtubesintothemanifold

and

solderalljointsexceptthe1x 1-inchtee,

which

willbe usedfortheinlet.

To

insuretheproperfit,

solderthisconnectionaftertheunithasbeen placed

on

the evaporator.

37. Nextdrilla holeinthetopofthe1x 1-inch outlettee

to

accommodate

a pieceof1/4-inch

copper

tubing.

Insertapetcockin line.

The

tubingshould belong

enough

to

bend

beyond

thedrippan. Thisrelieves

pressure fromthesystem, preventingairor

steam

lock,

and

isnecessaryforproperfunctioningofthe preheater.

38. Hereisacompleted tubebank,readytobe attached

toanevaporator.

39.

You

can

hang

the preheaterfromthehood,

suspend

it

above

thepan on

aluminum

anglesupports,or

40. For the free-standing model,

we made

asupport from threadedrod,

aluminum

angle,

and

flatstock.

The

threadedrods serve aslegs.

To

prevent

damage

tothepan,

we made

feetfromshort pieces

ofangle.

To

preventproblemswithrust,

more

costly

aluminum

orstainless steelrods

and

nuts

couldbeused.

41.

The

angle

and

flatstockformasupportforthedrip

pan.Flatstocksupportsthetubebank,too.Withthe

threadedrod,you canadjusttheangletoinsurethat

thedrippandrains

and

thetube

bank

staysatthe

properslope.

42.

Make

thedrippanjust large

enough

tocatch the

condensate fromthetube banks

and

manifold.

The

pan should havea drainin

one

corner.

43. After

you

assembletheunitwithapproximate adjustmentsfortheheightofthetubebank,

45. itisreadyto beinstalledontheevaporator.

46.

Make

yourfinaladjustmentsallowingforthe height

ofthetube

bank

and

drippan.Adjustthedrippanso

itslopestowardthedrain.

47. Place thetubebank

on

a 3 percent slope

up

fromthe

inletmanifold,

48. totheoutletmanifold.

49. Next

measure

thelengths

you

willneedforinletand

outlet pipes.

The

outletwill feedintothe regulator box.

50. Solderunionsinthelinessothat

you

can detachthe

51. Positionand soldertheinletpipe, 52. which connectstothesapfeedtank.

53.

Now

you

can modifythesteam

hood

toacceptthe

preheater.

Mark and

cutholes as small as possible

toaccepttheinlet

and

outlet pipes. 54.

Do

the

same

forthedrippan hole.

55. Finally,inserta

damper

about18 inches

above

the

steam hood.

Use

galvanizedsheet metalforthe

damper

and

anironrodfora

damper

control.

56.

We

constructedthisunit,not including thesteam hood,fora 3 X 8evaporatoratthe Forest Service

research laboratoryin Burlington,Vermont,for

lessthan $90in materialsin1980. Duringthefirst

seasonofoperation, if

you

burnoilthatcosts$1 .00

pergallon,

you

willsavein oilalone

more

thanyou payformaterials.

57.

Many

parallelflow preheaters, both

homemade

and purchased,arein usetoday.

They

provide

signifi-cant savingsinfuel,aswellas asteadyflowofhot

waterfromthedrippanforuseinthesugarhouse.

58. For

more

informationonthe

maple

sappreheater,

contact the Forest ServiceSugar Maple Laboratory

in Burlington,Vermont.