Note: Descriptions are shown in the official language in which they were submitted.
~ 2~75~37
. .
C~RT~OSTON 1~.5T~TANT ~Xr~N.~TON ~r~NK
n~cKc~QuNn o~ Tl-l~ TNV~.NTION
1. l;.el.cl of tl~e Tnvention
Ihe .i.nvcntio~ cn(ral.l.y rel.ates to expans.i.on and
stora~e tallks (llereinlfter collect;.vely referrc(l to as
ex~ansi.on tanks) used for example in el.oscd hydronic
heat.in~J systems ~ressur;.zed water systems eloscd clomestic
watcr systems and to ex~ansi.on tanks th.lt store water in
water treatment systems etc.
More part:ieularl.y a first aspect ot the invention
is direeted to a eorrosion resistant expansion tank that is
d:ivi.ded into t:wo secti.ons: one that may be prech~r~ed with a~
fluid under pressure (for e~ample a ~as) from a l~irst ~luid
souree; and the othcr l~e:in~ connected to a sceond fluid
souree for examr)le tlle hot watcr ~ource in a l~ot water
heat-.:i.rl(l systcln.
`` 2~ 75~37
Tanks contcmplated by tl-lis f.irst aspcct of the
invention are fab~icate(l from a pa.i.r of molcled plastic tank
sections that each int~-Jr;~l]:y i.ncl.ude tl~c connection to one
of the aforement;.oned fl.l.li.d sources; alld further include
n~eans for separatin~ th~. inter:ior of the tank into the two
sect;.ons referrcd to herei.nabove. Exampl.es of such means
for separatinq incl-lcle applicat.ion specific mcmbranes (s~lch
as diaphragms and bladders of varyinc~ types) that are
impcrmeable to the fluids storecl in the separate tank
sections.
Furtller aspects of the invent:i.on rel.atc to
aprarat-l~ ~or se~ur.illJ the me.lns Jor ser.lrat.i.n~ w.ith.in a
tank and to p2-ocess~s for cost cffect.i.vcly manufacturinq the
tan~s contemplated ~)y the first aspect of the invention
referrecd to hereinabove.
2. I)escr;.pt.ion of t-hc Rcl.at-e(l ~rt
Water contclins a.ir :i.n the a~sorbed state in nearly
inverse proportion to .i.ts te~mperat~lre. This ai.r Is
l..i.beratecl into the systcm when thc watcr i5 hcated and
acc~lm~llatcs i.n the compression tanl and other portions of
the hcating system.
2 ~ 75537:
A reduction in heatil~q efficiency results, makin~
continuous venting of radiators or conveetors necessary.
The water as it is heated expallds and moves into the
compression tank which i.s conllected to the pipi.n~ throuqh
which the water is circulat~d. Whcn the temperature of the
boiler water reachcs the desircd deqree, thc fi.ri.nq of thc
boiler ceases. The water be~ins to cool and contract. ~s
i.t cools, that part of the boil.er water i.n direct contact
w.ith air in the compression tanlc absor~s some of the air in
the tank.
Throu~il therma:L circulation tllis air char~ed water
in the compression tan~ is chan~e~ conti.nually 50 that i.n
the ncxt heatinq eycle thls re-abs,orbcd air :is liberat~d
into the system. This reversible proccss i5 repeatecl as
often as the firin~ cyc:l.e ;.s repeated and the boiler watær
.is heatecl and cool.ccl. ~5 a re~ciult of th:is ~roccss tllc
pressurc in the system varies considerably and evcntually
the system may cease to function.
~ xpansi.on tanks ;n clomcst-.ic watcr systems provi~e
an ai.r cushion for the s-lpply watcr. The air and water in
early systcms were in direct contact. ~ir bei.n~ soluble in
watcr, t-he watcr a~sorhs ai.r. The wat-.er :i.n thc ~ystcm mi~ht
evellt.ll.ll:ly ahsorh tJle .~.i.r CIlS~l.i.oll in t~lle exl)allsion t~nks,
1C~aV.il1~3 a stat;.c wat-cr system whi.c~l llCCC'S';itatC5 the
constant operati.on or rapi.cl cyol.in~J of: a press~lrc pump.
~ 2~75~3~
Subseq~lently an air surqe ch;lmber wa~-, provided whiell was not :
in direet eontact w:itll th2 water, thereby eliminatin~ the
need of the pressure pump o~eratinq every time a faueet was
turned on.
U.S. ~atent No. :3,0~5,Gl~ diseloses expansion ~ -
tanks which i.ncl~lde a ~I~.ir o~ holl.ow body members, ~aeh of
whi.ch have an encl and a tub~l.lar slcirt portion. The skirt
portions are unite-l in end-t:o-end relati.on to form a tank.
~l'here is a ~lex:ible diaL~hra-JIll ;.n ancl spanni.n~ the tank and
vin~ a per.iplleral. port.i.oll :in ~er~ heral enqa-~ement with
the skirt of one ol` the body members. ~ eontinuous
retainin~ ri.n~ en~Ja~es the per;.plleral port.ion arlcl retains it
in en~ac~ement witll the sk.irt of the body member. There is a
~roove in the exterior of the ri.n~ ancl a s~lbstantially
complement,-ll eorr~ ation in the ~ki.rt of the bocly member
compressin~ the peripheral portion into the ~roove to seeure
the di.aphra~m a~a;.nst movement endwise o the tank and seal
the diaphra~m to the ~kirt. See also U.5. ratent No.
2,695,753
U.S. ~atent No. 3,5?.~,~75, i.ncorporated herein by
referenee, (li.scloses an expans:ion tan)c wh:i.ch includes a
hol.l.ow bocly llavin~ a ~-,i.cle wall and end walls and a ].iqllid-
.i.mperv:ious l..i.ner hav.in-J an en(l wal.l. all(l a 5.idc wall. coverin~
the correspond.i.n~ encl wal.l ar-cl a porti.on of. tl~c 5i.de wall of
-the bocly in adjaeent non-adheri.ll~ rel.ation thereto. 'I`he
2 1 75~37
liner llas a periphcral el-)e portion contactin~ the side
wall. There is a flexibl.e di~pllraqm dividinq the interior
of the body into two sectiolls. One o~ the sections i.s
adapted to receive a 1 iqlli.r.l. The cliaphraqm has a peripheral
portion dispose~ in over~.yin-~ relat.ion to the ~eripheral
ed~e ~ort.ion of the liner. There is also mcans r~taininq
the peripheral portions o~ the diaphr~Jm an~ the lincr
aqainst the side portions o~ the di~S~ra~m ancl the liner.
The retainin~ me~ns incl.~ldcs ~ continuous rinq cn~qinq and
rcceivinq thc pcr.ipllcr<ll portiol ol- tlle di;lr-l~rlqm. Thc s:ide
wall engaye~ the ~cri~hcr)l c~lqe l)ortion of thc li.ner. rllle
rin~ an~l w~ll have a complemental r.ib ancl qroove secllrinq
t)le diaphra~m to the s:i.dc wal..l. Ihc dill)hraqm :i5 formcd
wi.th a l)ead on :its per:iphera:l. port.ioll w.ith the ~)eai hc.in~
received between the ri~ ancl the qroove.
U.S. Patent No. 5 3~36 ~25 (asi.qned to the s~me
assiqnee as the i.nstant invention; also i.ncorporatecl herein
by reference) is an improvement over the expansi.on tank
disclosed in U.5. ~atent No.~ 52~ ~75. ~ e retlininq rinq
that continuously en~qes the di.apl~r~m ~nd liner to per~orm
a secure seal was mo~ified i.n tlle incorporated 5 3~6 ~25
patent.
- 'I'he tanks clescr.il~ccl :i.n l~otl) o.l` tl~e :incorpor.lted
pat cnts lS~ ot a del~orm~ l.e di.~l)llra~Jm to (:l.i.vi~lc .1 tlnk i.nto
two sect.ions. One scc~.i.on is ~rechar~c(l W.ittl (~as ~nler
~ 21 75~37
pressure so that the diapllraqm is clisplaced to increase or
decrease the volume o~ this section accordinq to the
var.iations Oe the volume o~ water in -the other section.
~ s indicated hereinbefore wl~en the expansion tank
;i.s incorporate~ in a hot watcr heatinq system the variation
in volume is c~used when the l~oiler water is heated and
cooled in the normal cyclic operation of the heating system.
If tlle expansion tank is a part of a water system the .
variation :in vo~.ume occlrs as tap water :i.s clrawn and when
the pUIllp o~eratcs ~o rer)lac~ tl~ wa~?r drawn from thc tank.
~he liaphraqn1 separates the qas .in tlle one secti.on of the
tank from the water in the system.
In desi.~ninq metallic expansion tanks like those
descri~ecl in the incorporatc?cl patents i.t is :important to
address corrosion ~roblems wllich can have a siqrlificant
adverse e~fect on the useful l:i.fe of s~lch tanks. Tank
corrosion could becomc a serio~ls probl.em i~ there was direct
contact of w-ter (or watcr vapor) wi.th su~stantially the
enti.re :inner metal~ic s~lr~ace o~ the water receivinq secti.on
of ex~ansion tanks like tl~ose describe~ in the referenced
patents. Corrosion i.s act.ive in hot water system expansion
tanks )~eca~lse of the el.evatel tcml~eratllre of thc watcr.
W.i.th watcr system ex~ans:i.oll t.lnl~.i thc- coJros.ion var.ics in
accorclance Wit~l thc mincral alld oxyqen contcnt. of the wat~?r
:in a given ~.ocal:it-.y l`o -olve t-.hese ~ro~l.em<i metal. tanks
" ~ 2 1 75$37
:1.ike those deser;1~ed in t11-~ i.neorporatecl patents, use
additional components (I.ike the aforementioned liquid-
impervious liner, means for securing ~ liner within the
tank, ete.), to protect the inner surfaee of the tank
section that holds water. Other techniques ~1sed to solve
the aforementioned problems incl~1de co~tin~s ~ncl/or surface
treatments applied to the inside of a tank.
1~or the sake of i.ll.u.strat.io1l onl.y, reference will
be macle part.i.cularl.y t:o the :incorporatec1 5,3~G,925 to point
out several o~ the mo1e 5i~l11i 1.;.cant ~rol~.lems inl1erent in
present day eorrosion resistant metall:ic tanks themselves
and the known processes usecl to manufacture s~1ch tanks.
In order to ma1lufacture a steel. expansi.on tank in
accordance with the teac11in~s of the :incorporated 5,3~G,~25
patent, both tlle l;ner ancl diapllraqm must J~e sealed i.n a
metal tank half (referred to ~s the "water dome" in the
incorporated 5,3~6,925 ~atent). ~ retaining ri.ng (yet
another internal tank component) i.s usecl as an inside
support of a cold formed tan)c seal..
The "air dome" descril~ed in the incorpor~ted
5,3~,9~5 ~atent ;.s tl)en wel.ded to the water dome; wit1l care -
needin~ to ~)e exercised in t1~ tank des~ n to ins~-re that
the wel(l 1rca .i.s sufJ~ ie~1tly sr~ace~l I r oln thc (li~r)hr~l~ ancl
l.i.ner so tl~t these co111pon~nts are not dam.1(led dur.incJ the
(_ 2175337
welding process (~ue to the qreat variance ;,n the meltincJ
temperatllres of the materic~ls used, sueh as metal and
ruhber).
As those ski.ll.ed in the art will readily
appreeiate, eriteric~ such as the choiee of weld arec~, amount
o~ weld material used and type o~ joint heinq formed, all
affect joint strenqth and tank inteqr.ity. Onee aqain, the
coneern about heat transfer, overheatin~ and me].tincJ
comr~onents :installed i.n the tank, etc., a~ect the weld and
~joint tyr)e o~tions ~1vai1..lh:l.e to t:11e tank manu~ct~lrer.
Additional1y, in accordance wi.th the teachin~s of
the i,ncorporate~1 r~,~c3~"9~r) p~tent, the liner m~1st ~e sealed
to the tank's water connection; and t~)e water connection '~-'-'
itself needs to he formed in c~ separate set of cleta,iled
process steps, includinq bra~in~ or wel(1in~ the water
connection to the water dome tank half.
In s~1mmary, the incorporated ~,3~6,9~5 patent
exemplil-`ies several prob:l.em~i .inherent in the structure c~ncl
manufc~cturin3 processes associatecl with prior art metallic
expal1si,on tanks. 'I`ank i.nsert comr~onents, such as l.i.ners,
are req~1i,re~1 :i.n orc1er to r)rov:i.c1e corros,i.on protecti.on;
sepclrc-1te tank i.nscrt s.ec~l.inq -mechcln;.sms, 5uch c-lS reta;.ni.n~
rinqs, are required t-o seal the l;.ners ~nc3 ~ phra~ms wi,thin
the tanks; t~e li.ners need to be ~urt-,her sealed at the
~ 21 75337
tank's water connecti.on; the watcr connection (and the ~as
connection in many prior art devices) needs to be formed in
a set of separate process steps; care m~lst be taken in
performing various manufact-lring steps that call for the
application of heat to avoid damagin~ the l:i,ners and
diaphra~ms bein~ installed l~lrin<J tl-e manuLacturinq process;
and the type and s~trenqth of joints formed durinq-tank
construction are to a de~rec affected by the proximity of
the internal tanlc componcnts t.hat can l~e affected by
wh~tever jo;nt formi,n~J procc~s i.s ~Iscd.
All. o tlle ~roblems rcferre(l to llere.inabovc add
complex.i.ty to the tank m~nul-act~lrinq process in terms of
number of components and ~rocess steps req-lire~l for tank
fabrication; and the care tl)at neecls to he ex~rcised
t~lrou~llo-lt tlle tank fa~ricati,on process to assemble thc
vari.ous components, apply heat, etc. These problems and the
known solutions to these problems ~11. I)ave ~n ,impact on tank
reliability, tanlc life and tank manufacturin~ costs.
Those skilled in the art wil,l al50 reco~Jni~.e that
corrosion resistant non-metall:ic (~s~lall.y plastic) tanks
exist. Such tanks o~vLate tlle neecl for a liner to protect
the tank from corrosion; however, many of the sam~ problems
referre(3 to llerei,llhefore st..i.l.l al`fect known p].a,ti,c tank
desi,qn an(l manulacturi.n~ processes.
. 2175~37
~ or exampl.e ~lon~atic procluces a plastic tank that
i.5 fabri.cated without the use of a liner. Ilowever, a
diaphraqm (inserted into a tank half) needs to be secured by
a hoop pressed into the tan]c half; and then t}-e two domes
(a:ir and c~as) are friction-wclded toqether. ~clditionally,
both air and water fittinqs necd to be fastenecl to the tank.
rhus altl-o~qh the need for a liner is climinatcd the
Flomatic tank still requires the use o~ an internal tank
component (the hoop) to sec~lre the diaphraqm and still
requires the additi.on of scparatc a;.r and qas tank
connections since these connections arc not moldcd into the
tank halves (the domes).
The frict:i.on we].d stcp in thc proccss used to
fa~)ricate thc ~lomati.c t;~nk .is alr;o a potentill problem
source. -rlhose skilled :i.n the art wi.ll rca(1il.y appreciate
such a welcl (a friction wcld) lla5 a low joint e~ficiency.
In applications where jo:int c~ficiency neecls to bc hicJh
(hiqh pressure containment s:ituations etc.) to qet an
improvcd joi.nt usill~ fr:i.Gtion welcl:inq the welcl surface area
necds to be i.ncreased. ~lthouqh not clesirr.tble this
a~ditional surf-1ce area could be prov.i.cled for cxampl.e by
the use of wider tank componellts hav:inq a qrcater weld
surface area.
~175~37
l~nothtr Is:nc)wn r~ i.c tanlc, tl-e "ROm~t,c" l~ure
wat~er stora~JL? ve;:;L?l m~nllrlt~ rt?~l l)y ~t:r~lctli?-al l ihers (an
1~.';1 1;` Company) of Char(lon, Ohio, t,alies the form o~ a one
~iece blow moL(lt?cl plcl'~tiC })ott:l(? havincJ ~ d(lcr instal.led
ere;ll. 'J'ht? ~t,r~lctl1raL l il;.?rs plastic tank re~ ires i.ts
t-,er connL?ct; on to l~c sc.n I e~ a-~cl inst tlle tank ancl aq~3inst
t~ .? I~la(7der; t}~e ~asten;!lt-J or wL?~ i-nq on of an air
conn~ct;on; ~n~ s t:he ~)ot--t?nl-i-al for lo-;in~J ~.ir ch~rqe in
f; c 1-1 ~ISC h~callsc i nhcr cnt~ wcak 1~ i nts at thc a i r steln to
~ottlc int~erl~~lcL? ~n(l .~t thc v~rio~ls ot-llt~r 5cal.~; (wat,er
~-ollllt--~t-it l~l/})l.ttlt~t?r .1~ -)ct r~-~o~ t~ t-o tt~C?
~ n~tt~ ?!.i.t~r~
Otl:c- r L?~lm~lt?S O I t`.llllt 5 t !~ ;tl-~ttC t}lt-?
~3~-~'sL?I)t St.~t-C? o~ ht? Irt .illcl.u(lc t~ .s hy llyclrotccl~ (pl.astic
mol ~]ecl ~Ind thell cri mr)c(l on the ollts i~le to secul-e ~ }~l addcr);
met~a I I i ~ lnk.s - }~y We~,scl; Coml~any o t- I)ctr o i t M i ol~ iqan
t~-~hr;c.~-te~:~ vi~ pr-oces~ involvillq the wcl-lill~ of two stcel
clomes ancl :incital l; n~ ~ }~ kler (th~ rcsul t,~nt tanlis hav inq
the l)rOlllC?In'-; ol~ 'it:C?Cl t,,lnl;~, i n qcncr.tl wi t-h r-cq<~rcl to
m.~int cllancc, cor-ros;~n ~n-l t tlC? I-)ot-cnti~ or contalnin~tin~
tlle storecl w-~t,er, the r~otential for f:iel-l failurcs due to
}31~l(1der sc~l f~ re, ctc.); lllC't-all.iC tarllcs hy l~ell-Ritc
(t~cl}~ric.~terl ~-)y, !o-r ~ial~ lc?, cl inollillq l-wo cli.l~llraqmc. in5;clc
.~ we l de~l :;t e-- 1 t-ank o~ al t~-~rn.~l, ivel y c~ l i nct~; nq .n ~i i nql C?
hr~ nl l-c~ C?C'n ~IIC ';t ~ ','i .nll(l )11-.' ';t~ I d(-)mc); an~l
.~ 2 1 75~37
still other tanks which utilize fasteners to literally screw
tank parts toqether.
None of the known tank devices fabricated in
metal plastic or of any other material inteqrate both the
air and water conncction i.nto ~arts that arc ~lsed to
fabricate the outer shcll o~ thc tank; nor clo any of thç
known tank d~vices combine the desirable attributes of
proviclinq a low maintenancc corros.ion resistant tank that
can bc fabri.catcd usin~ a vcry small componcllt set (thrce
components accordin~ to a prcferrcd embod.i.ment of the
present invention): and very s.impIe process stcps to
assembl.e to aforcmel-t.ic)ne{l cc>mponellt sct.
~ ccorcli.nqly in view of the present stite of the
art i.l]ustratcd by tllC excmplary tan~s tauqht i.n thc
aforementioned patents and f~lrther illustrated by the
commercially ava;.lable tanls described herei.l~above it would
be desirable to provi.de a corros.ion rcsistant cx~ansion tank
design that (a) inherently resists corrosi.on and eliminates
the need for a li.ner to be instal.lecl in order to provide
corrosion protection; (b) does not rcq~li.re the lse of
separate tank insert sea]:inq mechanisms such as retaininc3
r;nqs or hoops to scal a. I-iaphra-Jm bl.acldcr ctc. wi.thin
t-hc ttn~ ) inteqr~t-c-. tanl conllcctiol):; (bct~l qls ~nd
watcr connect:ions) i.nto plrtC; th~t a~rc ~Isc(.l to fabri.c~tc the
outer s~lel.l of thc tanlc to thcrehy climinate hlvinq to form
~. 2175~37
sueh eonneetions and asso~iltecl seals :in a set of separate
proeess steps; and (d) inel.udes apparatus (means) for
seeurlnq within an expansi.on tank the means used for
separatin~ the interior of t21e tank into two separate
portions and at the same time provide for the joinin~ and
sealinq to~ether of tank seetions ~Isecl to form the exp~nsion
tank fluid eonta.inment vessel .i.tself.
2~urthermore it woulcl ~e desi.ral~le to be a2~1e to
provide a eorrosiion resi.stallt-. expansi.oll tank d~s.i.~n (ancl
relatecl tank manufaetllri.llq ~roeess) in whieh
(a) jo.int ~ffieieney ean he inereasecl w.i.thout havi.ncJ to
resort to wider tank component~ to obtain a qreater weld
surfaee area; (b) the aforementi.oned means for seeur.ln~ is
desiqned to hold the means for separati.nJ ~e.~. a
diaphra-Jm) in plaee durinq tank assembly and durinq tank
operat;on; (e) the a~orement-.i.onecl means ~or seeurinq is
~urther desi~necl to provide a vehiele for ~ormi.nq a stronq
i.nter;.or lap joi.nt to repl.aee for exalllpl.e wea).er pri.or art
fricti:on welcls etc.; (d) the number of man~lfaetur:inq steps
that call for the applicat;.oll o~ heat cluri.n~ the
manufaeturinq proeess and the numher of internal tank
components that e~n he affectecl 2~y whatever joi.nt forminq
proeess is used are mi.nimi.~.ed; and (e) the overal.l
compl.exit:y of the t-ank m.~nnfact~lrin~ process :i.5 redueed in
terms ot- n~ ter oL ~omponellts ~nd procc-s; ;teps req~l.ire~ for
~1 75~37
tank fabrication to thereby improve reliability tank life
and lower tank manufacturin~ eosts.
SUMM~Y 0~ Tlll~ ]NV~NTTON
Aeeord;ngly it is a qencral objeet of the
invention to prov.i.de improve(l cxpansion tanlcs For use in hot
water heatin~ systems press~lri~.ed water systems an~ the
like.
It i.s a furtller qeneral ohject of the lnvention to
provide improved expansi.on tanks for use as ind;cated
hereinabove whieh are eorrosi.on res:istant.
l~urthernlore it-is a ~eneral objeet of the
invention to provide a corros:i.on ~Csist~llt expansion tank
tllat may he div:ide(l :into two sect:.i.ons: one that may be
prechar~3ed w;th a f~ui(l under pressure (for example a qas)
from a first flui.d souree; alld tl~e other he:ill~ connected to
a seeond fluid source for examr)le the hot water source in
a hot water heatinq system.
It is a sr)ec-i.fic oi~ject of the i.nvention to
prov:ide a eorrosion res;.stant expansion tall)c that ean he
fabrieated from a pair o~ tan)c sections (preferlbly molded
st i.c tanlc scct i.ons) tl~at. cach :i ntc-lral.l.y .i nc~ c t.hc
connect:ion to one o~ the aforement;.oned fluid sources; and
1~1
. ~ 21 7;5~37
further include means for se~ratinq the interior of the
tank into the two sections referred to 2-ereinabove.
A still f~lrther speci.fie object of the invention
is to provide a corrosion resistant expansion tank desiqn
that (a) inherently resis~s corrosion and eliminates the
need for a Iiner to b~ install.ed in order to provicle
corrosion protecti.on; (b) ~loes not req~lire the use of
separate tank insert sealinq mechar)isms such as retainin~
rinqs or hoops to scal a di.apllraqm ~ladcler ete. w.ithin
the tanlc; (e) inteqrates tlnk collneetiolls (~oth qas ancl
water eonneetions) into p~rt; that are Ised to abr:ieate the
outer shel.l. o the tanl~ to thereby elim.inate hav.i.n~J to form
such eonneetions ~nd associ.ated seals in a set of separ<~te
process steps; an-~l (d) i ncludes apparatus for seeurinq
within an exp.lnsiol- tank the means used for separatin~ the
inter;or of the tank into two separate portions and at the
same time provide for the joininq and se~l;.nq toqether of
tank secti.ons usecl to form tlle expans:ion tanJc fl-li.d
eontainment vessel itself.
I-urthermore :it i.s a specif.i.e ohject of t21e
.i.nventi.on to ~rovide ~ corrosi.on resi.stant exp(~nsion tank
desiqn (an~ related t:ank man-lfatllrin~ p~-oeess) in W~l:iCh (~)
jOillt cl~~ic;~ncy C~ c ;ncreasecl w;.t:hont~llavi.ll~ to resort
to wicler t-anl~ Co~ ollCIltS to obta:in a qreat~er weld .urf~lce
area; (b) the aforemcnt:ionecl means or see-lri.nq is desi~ned
-
t ~ 2175~37
to hold the means for separat.incJ (e . q . a cli~phr~m) in
plaee durin~ talllc aSSClllb] y and durin~ tank operation;
(e) the aforementioned means for seeurinq is further
desi~ned to provid~? a vehiele ~or formin~ a stronc3 interior
lap joint to replaee, for example, weaker prior art frietion
wel.ds, ete.; (cl) the number of manl.lfaet-lr;.nc3 steps that call
for the application of heat dllrincJ the manufaeturinc3 proeess
and the number of intern~l. tank eomponents that ean be
affeeted by whatever joi.nt formin~ proeess .is used, are
minimi~ed; and (e) the overal.l. eompl.exity of the tank
man~ etllr.in~ prc)eecis is redule~l in terms of. n~ lber of
eomponents and proeess steps requirc?cl for tan]c l-abrieation
to thel-e~y improve relia)~.ility, tank li~e and l.ower tank
manufaeturi.n~ eosts.
Tlle a~orementioned objeets of the i.nvention are
aeh.i.eved in part l~y r)rov:idinc~ a pair of t:ank seetions that
intec3rally inelude first and seeond lui.(1 eonneetion means
(for examl)le, water and cJas eonneetion means) whieh when
joined to~ether (the tank seetions), with a diaphraqm,
hlad(ler or other means ror separati.n~J seeured there~etween,
form the expans;.on tank fluid eontai.nment vessel. -
More part:ie-llarly, a first apeet o:f the :invention
is direetecl to .~ eor-rosion :res.istal~t e~r),~niioll tank that is
liviclc?(l into t-wo ;e(tionC;~ one c)~ wl~ieh may (a-lt:llo-lcll- not
neeessar.il.y) l~e prc?eh~rc~c?(l w:ith a f`l.ll:id ~Incler pre<.;s~re (I.or
2175~37
exampJe, a qa5) from a ~irst fluid souree; whilc the other
section i~ connected to a seeon(l fLu:id souree, for example,
the hot water so~lrce i.n a l~ot: water heatinq system.
Aeeord.inq to a pre~rred embocliment of the
i.nvcntion, the t~nk eomprises a ~air of molded pl~stie tank
seetions. Eaeh of the mol.ded pl.astie tank seetions is
desi.qn~cl to inteqrally inelu-le tl-e eonneeti.on to one of the
aforementioned fl.uid sourees. The tanks are f~lrther
des;.c~i~etl to .i.nelude the mellns for s~par.~t.in~ thc tank
inter:ior :int:o the two ~;ect:i.ol~s referrell to ~)er-einabove.
~ urther ~spects ot` the :i.nvention relale to
apparatus (means) ~or seeurin~ ttle means for separatinc)
wit~l;n ~ tank; and to proeesses for eost effeeti.vely ~ -
manufaeturinc~ the tanks eontemplated hy tlle aforementioned
fi.rst aspeet of the invention.
Aeeordinq to a spee.ifie ~irst embo(li.merlt of the
invention, ~ eorros:i.on res:istant expansion tank, eomprises:
(a) a ~irst molded plasti.c tan]c secti.on ;nt.eqrally ineludinq
first eonneetion means l~or enabl:incJ ~lui.a from a first ~luid
souree to ~e pLaeecl .in fl.u~l commun.i.cat.ion w.i.th a first
~ ter.ior portion o~ tlle ~pans:ion tanlc; ancl (b) a seeond
mol.de~ st.i.e tank seetiorl, wl)ieh when joined together with
tl~ ~i.rst moLde(l pl.asti.c tallk seet.ion ~orms the ex~nsion
tan]c fl~li.(l eontainmellt vc5scl, ;.ntecJral.ly .inelu(li.nq second
~_ 2 ~ 75~37
connection means for enahli.n~ fluid from a second fl.uid
source to be placed in i-luicl communi.cation with a second
separate interior portion of the expansion tank.
The aforemcntion~ fir.st an~l s~cond conncction
means provide passa~cways throu~h which flui.d from the first
and second flui.d sourccs rcspectively may he introduced
into and may be withdrawn from the expansion tank.
Purtl~crmore accor-(li.nq to thc aforcm~nti.one(t
s~eci.f.ic first elDlo(lim~nt. o~ the invcnt.i.on thc tank
compriscs means f~or se~aratin~ thc tal-k into the
aforemcl~ti.oncd fi.rst ~nd secon(l i.ntcr.ior porti.on-s wllcrc the
means for separati.nJ s~ans the interi.or of thc tank ancl is
madc of a flexibl.e material that is impermcclbl.c to a
pre~etermi.l-e~ set of flui.ls incl.ucl.in~ thosc f.`luids providcd
by the aforementioned first and second fluil sources. In
practi.ce the means ~or separat:ing can bc rea.l.i7.ed by for
example a flexible li~phra~m or bladder.
Stil.l f~lrthcr accord:inq to tlle aforemcntioned
sl-)ecific first emhodin)cnt of the invention thc tank
includes a means for securi.n~ the means t`or separatin~
(within the tank) v:i.a a joi.nt formed bctween the first and
second molded ~l.as~ic tank scct-:i.olls.
ln
2~ 75337
The means for secllrinq accordin-J to yet another
asp~ct o~ the invention prefcrably compr.ises: (a) a soc~et
integrally formed i.n the first molcled plastic tallk section
for rec~ivinc3: (al) a tancJ intec3ral.1y formccl on the
aforement.ioned second moldc(3 plastic tan~ SCCtiOIl; and
(a2) a joint formin~J matcr:ial clcpositcd into the socket
clurinc3 tank assembly for usc in jo.i.ninq aforemcntioned
first molded plastic tank secti.on to the second molded
p].astic tank section and securin~ the means for se~arati.n~
therel~etwecrl; ~nd (h) a t~ny intcyrall.y fonned in the
seconcl moldcl plastic t.anl secti.oll clcsi~llcd for in-;crtion
into the sockct f`or use in joininC~ t)-e f.irst moldcct plastic
tank secti.on ancl thc sccond mol.(led p:l.ast:i.c tan~ sect;.on
toJetller to form the cxpanc--~i.on t nk f.lui.(l containment
vessel.
~ ccorcliny to a preferrc!cl cl~ o~l.imcnt o~ the
i.nvent:i.on the socket and tanc~ l`urtl~cr comprisc (a) a first
socket surface and first tanq surface respectivcly desi~3ned
to accommodate the installat.i.on and sccurinq of a porti.on of
tlle means for separat;.ny thcrc~etwecn w:ith the means for
separatinc3 beinc3 shaped to facili.tate the enc3acjcmcnt of a
portion o~ the mcans for ~.eparatiny w:ith at lcast a portion
of t~)e first socket surface durit~q tank asc-,emhly; anct (h) a
secon-t soc);et surl~ce ~n(l -;ecc)llcl tany sllr-t~acc rcspcctively
wh:i.ch whcn juxtapo5cd rOrlll a citop. ~urther~nore thc sccond
soc~et surfacc anct seconcl tanJ sur~.lce .II-C ~rcferahly
1.~
C 2~75~37
l.ocated in proximity to thc exterior wall of the tank (in
relation to the com~ination of the socket, the portion of
the m~ans for separatinq l~c.i.nq secured and the tanq itself,
the aforementione~l comhinat:ion beinq located toward the
interior wall of saicl tank).
~ urthermore, accorcl:i.nq to furthcr aspects of the
invention, the aforementioned joint forminq matcrial may bc
characterized as a material that inclucles a thermoplastic,
sllch as commcrc:ia'Lly ttlcrmor).l..3sti.c cc)m~ositc matcr;als
formect as ~ m.ixture of tllc~rmo~last.i:c ancl mctLll ~artic3es: or
a wel.c~i.nq mater:i:al whi.ch ~-lows upon bci.nq hci~tcd. One
~articularl.y ~l~e~ll. wcldin~ m.ltcrial. conteml~l..ltccl l>y t~c
.i.nventi.on is a mi.xt~lre of thermoplastic and mctal parti.cles.
Furt}~er yet, accorclinq to a preferred emhocl;.mcnt
of the invention, tlle aforemcntioncd sockct ancl tancJ are
clesiqnecl such tllat weklinq mater.ial depositcd in the socket,
~Ipon bei.nq heatecl ancl ~lpOn beinq compres~ed t>y the socket
-ancl tanq bein~ forcecl toqct-hcr ~lnt:il. the aforementioned stop
is reached, flows from the point of depo~it in the socket
away from the stop ancl toward thc coml~ination of the socket,
the portion o~ the means for separ.lt.in~ beinq secured and
t~)e tanq, to form an interior 3.ap joint.
~( 2175~37
.
Accor~in~ to one emboclim~nt of th~ invention, the
interior lap joint forms a wel.d th~t joins the tan~ and
socket, together; but does not include the means for
separatinq as part of the joint. I~or example, a means for
separating m~de of r~ ber wou:l(l not be include~ in welds
contemplated by this emboclimcnt of the invention. llowever,
accordin~J to another embo~l.i.ment of the invention, the
interior lap joi.nt forms a weld that joins the tang, socket
and th~ aforement;one~l means for separatinc~, to-~ether. Such
a wel.d eo~lld be empl.oyed wl~ere the material usecl to
~abricate tlle mealls for se~arati~ as a mcltin~ temperat~lre
that approximates tl~at o~ the tank sections (the tanc3 ancl
socket port-;.ons thereo~) and wcld materiAI.. ~or example,
the meclns for separatincJ co~lld he fabri.catecl us:inc~ a
fl~xi.b].e tl~ermoplast.i.c m;ltcria.l. s~lc~h as a thermop].astic
elastOlllCr/tl-CrlllOSCt rUi)t-er COlllpO5ite.
~ ccord:inc~ to an alternate emhodiment of the
inventi.on, a corrosion resistant expansion tank contemplated
hy the teachinc3s herein compri.ses: (a) a first molded
pl.astic tank sect;on incl~ld:i.nq a ~.irst tank connection
i.ntec~ral].y molded therei.r~ )) a seconcl moldecl plast;.c tank
sect;on, wh;ch wl~en jo;.ne(l to~etl~er w.i.tl~ the ~irC~t lllOldeC
plast;.c tank sect;i.on l~ornls tl~e ex~ans:ion tank fl.~l.i.d
containment vessel., .incl~ J a seconcl tank connect:ion
int~ral Iy mOI(lC'(l tl~C?rC'i.n; ((`) InC?anS for separatinc~ the tank
.into a first i.nterior- port.i.on and a seconcl :interior portion,
~ 21 75~37
the means for separatinq )-)einq secured betwecn the first
molded tank section and the sccond mo~ded plastic tank
section; and (d) means for securinq the means for separatin~
in a joint formed between thc first molded tank section and
tlle second molded plastic tallk section.
.
~ ccordi.nq t.o this al.ternate eml~odimcnt of the
invention, the f:irst molde-;l pl-~st:i.c tank section further
compri.ses (a) a qas dome whi.cll m~y he connectecl to a qas
source vi.a tlle fi.rst tank cc)llnccti.oll :inteqrally moldcd in
tlle first mol.de~l ~l.asti.c tan)c sect.i.on whcrc;n _aicl ~as clom~
i.nclu(les a seal.i.ng surfacc; (b) tl-e seconcl molded plastic
tank section furthcr comprises a water dome c~esiqnecl to fit
into the qas clome which may be connectc~ to a water source
vi.a the secon~ tank connect;on inteqrally molded in the
second moldecl pl.lstic tank section; (c) at least a portion
o~ thc means for separatinq .i.s formecl to fi.t onto (an(l/or
"into" de~i.ned hcrci.n to be :includcd in the term "onto")
the sealinq surface of the ~as clome; and (d) the portion of
the means for se~ar~t:i.n~J i.s seal.ed bctween the qas dome and
the water dome by li.tti.nq thc port.ion of th~ means for
separatinq into the sealinq surface and thcn jo;.nin~ the ~as
dome and sa:id water dome toqether to form a lap joint by
compress:inq a matcr;.al that inclu~es a thermopl.astic (or
some othcr wcl-1in-~ m~t-r.i.~l) until. 1~ stop is re~chccl.
( 21 75~37
~ s indic~te~ tlereinbefore, further aspects o~ the
:invention are directecl to the apparatus (means) for securin~
the means for separatin~ within a tank per se (the novel
mcans for sccur.inq havinJ heell described herein~eforc); and
to processes for cost cffectively manufacturin~ the tanks
contemplatccl ~y tlle various emboclimcnts of tl-e ;nvcntion
referrcd to hereina}~ovc.
In particulL1r the invcntion contcmpl.atcs a
proccss for manufacturinq ~ corr~s:ion res.;.st~nt e~ansion
tank, compris;n~ thc ;teps of~ ) fabri~ati.nq a fi.rst
plastic tank section th~t inteqra~.ly incl.udcs f;.rst tank
connect.ion me~ns; (h) fabr.ic.lti.n~ ~ second pl~st;.c t~nl-
secti.on that intc~rall.y .i.ncl.udcs scconcl tank connccti.on
means; (c) inserti.n~ hetwc?en thc first plast:i.c tank section
an-l the secon~l pl.ast;c tank secti.on, means for ;cparatinq
the tank into a first interior portion ancl a second i.nterior
port.i.on; and (d) joi.nincJ the irst plastic tank section and
the second plastic tank section wi.th thc means for
separati.nc3 nsertecl tllcrc~etwecn, to therc?hy form the
expans.ion tank flu:i~l containment vessel with the means for
separatinc3 s~cured therein.
~ urther cxem~lary process steps contcmplated by
tlli.s ls~ect o r ttlC ~ VCIlt_iO~ lll(l~ t~ ? '-;t:CpS O f-:
(1) inte~r~l.ly f-orlllinq .~ sock-t i.n tlle f..i.rst pllst.ic t~nk
section for receivill~J the clcLos;.t of a joint ~ormin~
` (~ 2175~37
material and for receivinq a tanq formed as part of the
second molded plastic tank ~cction; and (b) :inte~rally
forminq a tang in the second molded plastic tank section
that when inserted into the socket and joined therew.ith form
the expansion tank fluid con-tainment vessel.
Accordinq to a preferred embodiment of the
invention the step of forminq a socket further comprises the
step of formincJ a fir-st sockct surfacc ancl the step of
forming a tan~ furthcr comprises tl~c step of formin~ a first
t~n~J sllrfacc whcrc.i.n tl)c f irs~ soc~e~ s~rfl~cc ~ln(l tllc first
tan~ surface are dcsi~ne(l to accommodatc tlle in;ertion ~ncl
secur;n~ of a port;on of tlle melns for scparatin~ :
therebetween.
. .
lurthermore accorclinq to a ~referred embodiment
of the invention the portion of the means for se~aratinq to
be secured is shaped to facilitate its enqa~ement with at
least a portion of the first socket surface durinq tank
assemhl.y; and at least a porti.on of the first tanq surface
i.s rouqhened to enhance the abi.l;ty of tlle portion of the
means for separatinq to be secured between the first tang
surface and the first socket surface.
~ ti.-l.l t~lrthcr thc prcf.`errccl cmbod.i.mcllt of tlle
il~v~ ion ~(>I-l~:c~ ; t:~c l`o~ wil~-J l~ lrin~J ~.~c~
(a) lorm;n~ a sccon~l soclet ;~lrfacc lnd second tancJ surface
2~
~ 2175~37
wherein the second sock~t surf;lce and the second tan~
surface when juxtaposed orm a stop; (b) formin~ the second
socket surf~ce and second tanq surface in proxim.i.ty to the
exterior wall of tlle tank (i.n rcl.at;.on to thc first socket
surace and the f;rst tan~ surface which arc formed in
proxi.mity to the intcri.or wall. of thc tank; and (c) shapin~
the socket ancl tan~ such ti~at wcl.clin~ matcri.al. deposLtecl in
tlle socket upon bei.n~ he.lted ancl upon l~ein~ compressccl by
the socket and tan~ bci.n~ forcccl to~ethcr ~lntil the stop is
reached flows rom thc po.i.nt of dcpos;.t in thc socket away
from the stop (towar(l the combinclti.on o~ tllc soc~kct the
portlon o~ the means for separatin~ bein~ sccllrcd and tan~)
to form an inter:ior lap joint.
~ urthcr yet accorcl:i.n~ to a prc~erred em~odiment
of the i.nvention thc first pl.asti.c tank sectiorl and the
seconcl pl.ast.ic tank scct:i.on are formed vi.a an injccti.on
molclin~ process; and the aforementioned manuacturin~ step
of joininq further comprisos the steps of: (a) dcpositin~ a
weldi.n~ m~terial (such as the aforement:i.oncd mixture of
thermoplast.ic and mctal parti.clcs) into thc socket;
(b) heatinq the weldin~ materi.al; and (c3 comprcssin~ the
heated weldin~ material hetween the socket and tancJ until
the stop is reacllcd.
~ ~ 21 75~37
f
An alternati.ve process for man~Ifacturin~ an
expansion tank, as contempl.atecl by the invention, comprises
the stcps of: (~) fabricating a one picce mol.clcd p1astic ~as
dome includ;.ng an inte~rall.y ormecl socket, further
includin~ a sealin~ surface, and gas connection;
(b) fabri.catin~ a one pi.ece mo1(1cd plasti.c water clome
includin~ an inteqrally ~ol mecl tan~ and water connection;
(c) fittin~ a diaphraqm onto the sea1in~ surface o~
the socket; (d) clepos;tin~ a welcl:i.n~ mater:ia1 i.nto the
soc~kci-; (e) h~.3t~ J ~.hc wcl.(I.i~ materi.l'I; alld
(f) compressi.Il~3 thc heatc(I wc1diIl~J mater:i.al ~etwecn
the socket ancl tan~ ~Intil a stop formed by the sockct and
tan~ is reache~.
~ `he invention, as excmplifiecl by tlle various
aspects thereof dcscr.i~ed here;.Ilahove, ~~eat-~res (when
compared with the pr:ior art clescribcd here;.nbcfore):
~a) fewer parts; (b) f~ id connectioIls mol(led .into the'tank
secti.ons (domcs) that when jo.ined (thc tank sect:ions) form
the containment vessc3. itsc].f; (c) tlle use of plasti.c
materials that clo not rcqui.re 1iners or sca1s; (d) a
diaphra~m (or bl.a(l(ler, etc.) captured bctwcen the dom~s; (e)
a simp].i~'ied set of prod~Ict;.on processes; (f) a tank that
is corrosion resistant ins:iclc and O~It; (~) a tank that does
not retluirc o-Itside f.in;sI~;.Il~ (e.~., pa-iIltin~) ~or ~inish
~rot-cct:ion; (Il) a rc1.iaI~.e tank thllt: c.~n ~.~f-el.y )~e ~It.ili.~cd
for a variety of applications i.ncludin~ watcr stora~e
26
c ` 21 75~37 - I
applications and hiqh pre~s~lre environments due to the
inherent stren~th of the lap jO.illt formed ~Isinq the proeess
deseribed llereinl~eforei an(:l (.i) a tank th~lt ean be taken
apart by reheatinq the aforementioned interior l~p joint
for inspection repair and/or recyclinc3 purposes.
These and other ol~jects emhodiments and features
of the present invention and the manner of o~tai.ni.nq them
wi.ll. beeome ap~arent to those sli.lled in the art and the
invention itself will ~e hest ~Inderstoocl ~y referenee to
the fol.~.ow:inq neta;lcd l~escr;ption rea(l in conj~lneti.on with
the aecompanyinq ~raw;.nq.
~TI~ n~ CRTII`ION 0~ AW.NC
~ IG. 1 is a vertical cross-section view of an
expansion tan) contemplated by one em}~odiment of the
invention. IIC. 1~ is a vertical. cross-sect;.on v-iew of the
tank depi.eted in I~IG. 1 carryinq an a:i.r charqe.
IIC. 2 is all enl.arqecl vert.i.cal. parti.al. cross
sect;.onal view of a portion of the e~pansion tank depicted
i.n I~IG. 1 depictinq exemplary means for see~lrin3 a means for
separatin~3 (the interior of the tank ;.nto two portions)
between the tan~ sections wherci.n t.he ~lepict~d means for
seeuri.nq holds tlle means for separat;.n~ (e.q. a cliapllraqm)
in plaee durinq tank assemhl.y d~ i.nq tank.operclti.on alld
2~ 75~37
provides a vehicle for formin~ a stron~ interior lap joint
to replace, for exampl.e, wealcer pri.or art friction welds,
etc. More particularly, i.n FIC. 2 depicts port.ions of the
tank sections and means for separatin~ prior to these
components be;.ncJ joined and secured toc~ether.
FIG. 3 and FIG. 3A clep;ct the components shown in
FIG. 2 joined to~ether and securec~ in accordance with a
fi.rst and second èmbodiment of the invet-tion, respectively.
I~IC. ~ is a vert.ic.ll cross-scct-.ion v:iew o~ an
alternate emhocliment of an expansion tank contemplatecl by
tlle invention in wl).i.ch one of tl-e f`luicl connect:i.ons is shown
molded in a cl:i.ffcrent port:i.on ot- onc o~ the tank scctions.
FIC. ~ clep.icts, in the form of a fl.ow clia~ram, a
set of tank manufacturin~ process steps contcmp.lated by an
illustrative embod.iment the invention.
FIC. 6 depicts, in the form of` a flow clia~ram, a
d;.fferent sct of tank manu~acturin~ process steps (c1i~ferin~
from the set of steps clepi.cte~cl in FIG. r~), as contemplated
l~y an alternate embocl;.ment the inventi.on.
~ 2~
2 1 75~t37
Dl;~ l' r..l;~ I)F'S CR T r'r T ON
An illustrative eml)oliment of a corrosion
resi.stant tank of the type eontemplated by the invention
will ~e set forth herein~f`ter with referenee to ~I~S. 1~
It is intended t-.hat the followi.n~ deseription of
the tank means for securin~ used in the tank (clurin~ the
tank eonstrl~etion process and dur:in~ tank operation) ete.
all dc~.i.eted l-:CCS. 1-;l w.i.ll t-each thc l-r.i.nci~als of t))e
invent.i.oll. Tt~ose ski.lled in tlle art will readil.y a~preciate
that the teaching is bei.n~ set forth in the context of an
exemplary tan~ structure only ancl that ~ucl~ structure may be
v~rie~ i.n praet.ice without depart:inq from the spi.ri.t or
scope of the invention wh.ich is intencled to ~e lim.i.ted by
the clai.ms only.
In partieular those ;k:i.lle~l in the art should
readily ap~reeiate that in t~lC eontext of-` presentin~ the
i.l.lustrative embod.iment of. tllc invention certai.n terms will
~e use~ for the salce of illustrat.i.on only. Ior example
reference will sometimes be macle herein to a;.r ~as
and/or water as the f-lu-ids to he contained ;.n the tclnk;
but these partic~llar ~lu.i.ds are meant to be il.lustrati.ve ;.n
natl~re onl.y since ~.IlC tanks contempl..lte(l ~y thc :invent.i.on
lllay ~)e usecl clS fluid COllt.l inment ves~ ls ;n ~Jcncral (wi.ttlOut
li.mitation as to the typc of flu;.ds t~ei.n-J eonta.i.ned
~ 29
f~ - 2 1 75~37
there.in). A further example is that specific references are
made hereinafter to a "diapl~ra~m" as a means for separatin~
the interior of the illustrative tank into two sections;
however, alternate means for performin~ the des;red
separation (like a bladcler) are contcmplatcd by the
invention as well.
F;nally, bcfore clescribin~ the ;.nstant .invention
and for t}lC sake of- complctcncss, re~erencc sholll.d bc made
to the ~reviously incorporatecl 5,3~6,925 patcnt, i.n
part;.cular to ~IC. 3, ~TC. ~ and thc dcscr:ipti.on thercof in
tlle 5,3~3G,925 patcnt, f~or an cxplallat:ion oJ hot. watcr
heat;n~ systcms ancl prcss~lr:iY.cd water ~ystcms in ~eneral
(shown ;.n schematic form in ~TC. 3 arld lTC. ~ of thc
i.ncorporate(l rc~erence), in Wlli.CIl tl-e tan~ tau~ht herein may
be used.
r~eference shoulcl now be made to ~IG. 1 which, as
indicatecl herei.nhefore, is a vertical cross-section vicw of
an expansi.on tank contemplatecl hy one em~odiment of the
invention.
~ ccorclinq to thi~ :i.l.l.ust--ative embodimcnt of thc
inVCIlt.iOn (al.SO a prercrrc(l c~ o(l:imcnt of~ thc invent;on), a
cor~os.ioll res:i.stant expansion tank ]oo as ~;hown :in rIG~ ]
incl.u(lcs: {a) a fir-st molcle(l plasti.c tank scct:ion 1.0].,
~ 2i75~37
intecJrally includi.nq f irst: conl1eet.iot1 means 102, for
enabl ;nq fluid from a first fluicl souree (not shown) to be
plaeed in fluid eommunication with a f-irst interior portion
103 of e~pansion tank 100; clnA (b) a seeond molded plastie
tank section 104, wh;.ch when joi.ned toqether w.ith f~rst
molded plastic tank secti.on 1.()'1 forms the expansi.on tank
~luid containment vesst-~l 1()0, inte~ral1.y inclu(linq seeond
connection means 105 for en~ .i.n~ fluid from a seeond fluid
source (not shown) to he ~l.ace~1 i.n fluid communieation with
a seeond separate interior port ion 10-. of expansi on tank
100 .
I; irst eonnection mcans 102 and second connection
means 105 provide pass~c~eways through wh,i.ch flu.id from the
first and seconcl flu:id sources respeetively, may be
introduced i.nto ancl may l~e withdrawn from expansion tank
100. Aceordin~3 to one emboc1iment of tl1e invention, f.irst
connect:ion means 102 and second connection means ] 05 are
threaded (as st)own for example at ] 15 in FIC. 1) to permit
easy instal.lation o~ v~.1ves (not shown) into the t,lepicted
passa~eways . Exemp],ary tank lO0 shown i n EIG . 1 also
;neludes tank stand member 120 (and corresE onclin~ portion
1'~0a of that member in the dep:i,ctec1 vertical cross-section
view), wh.ieh is prefera~l.y i.nt.egr~l 1y f~ormed (althou~h this
.is not ~ re~ 'irement to pract,.ict.~t1 the i~nvel1t.it n) as part of
t.lnk sect.i.on 101 to serve (~ se ~pon wl~icll the t.~nk may
he rested in an ur~r:i~ht posi.tion.
~ 2 1 75~37
Furthermore, accorclin~ to the aforementioned
preferred embodiment of thc invention, tank 100 includes
means for separatin~ (shown as 107 in FIC. 1) tank 100 into
the aforementioned first ancl second interior portions (10~
and 10~ res~ect.ively, with fi.rst interior portion 103 bein~ -
located betweell means ~or scr)aratin~J 107 and thc intcrior
wall of tank section 101); where means for separatin~ 107
spans the inter:ior of tank 100 and is inacle of a flexi.ble
mater:ial that is imperm~al-le to a precleterminc(l sct of
flu;ds, includin~ those fl~li(ls provi.dc~l by the
aforementioned first and second fl~lid sources.
In pract;ce, means ~or se~aratin~J 107 can be
realizecl by, for exam~le, a flexihle diaphra~m, hladder or
some other applicati.on specific mcmhrane that separates a
the expansion tank into two chambers. ~or many water
storaqe and watcr heatinq applications it is des;.rahle that
separate water and air chambers be formed usin~ a materia'l
that ;s not permeahIe to ~a5 ancl whi.ch allows the a;r
chamber to be prechar~ed. ~ vertical cross-scction view of
the tank depicted in ~IG. 1 carryi.n~ an ~ir char~e, is
il.lustratecl :in ~IC. I.A where means for separat:i.n~ 107 (in
tank 125), is shown deformed by the air charqe at 126.
2 1 75~37
. Still further w;th reference to ~IG. 1, accordin~
to the aforementioned prcfcrred embod:iment of the i,nvention,
tank 100 incl,udes means for securing (shown as 110 in
FIG. 1) the means for scparati.n~ 107 (withi,n tank,100) via a
joint forme~ between fir~-t mo].ded plastic tank section lol
and second molded plastic tank section 10~.
Reference sho~ld now be made to rIGS. 2, 3 and 3A,
where means for securinq ll.0 from ~IC. 1 is shown in ~reater
cletail. In particular, means 1.10 is shown i,n l'IC. 2 to be
holdin~ mcans ~or sel~ar~lt.i.n~ 107 (c.q., a d:iaphra~m) in
place durin-J tank ~.isscml~ly. ~l~hc same Incans 1l.0 is clcsi~ned
t:o hold means for se~aratinc~ 1,07 in pl,ace dur:inq tan~
operation (illustrated by the diaqram shown in ~IG. 3) and
providcs a vchicle ~or form:i,n~ the ~forementi,oncd stron~
interior lap joint (also shown in r'IG. 3, at 150) to
replace, for example, the weaker prior '~rt friction welds,
etc., di,scussed herei.nbefore.
In FIG. 2, the d~pi,cted portions of tank sections
101 and 10~; and me~ns ~or scr)ar~ti.n~ 107, are shown prior
to these components bcin~ joincd ~nd secured. In FIG. 3,
the components dcpicted in l'TG. 2 are shown joi.ned to~ether
ancl secured i,n accordance witl- a pre~erred cmbodiment o~ the
invention.
2 1 75~37
More parti,cular],y, a5 may be seen with reference,
to l;'IC. 2 and accordinc3 to yet another distinct aspect of
the invention, means `or securin~ 110 (a specifi.c
illustrative embodiment of, the preferred securinq mechanism)
is shown to inclucle sooket 170, inte~rally formcd in first
mol.ded plastic tank sect,ion 101, for receivincJ: (a) tan~
1.71, inte~rally forme(3 on thc aforementionec,l second molded
plastic tank section 10~1; and (b) joint forminc3 material
172, deposited into socket 170 durin~ tarlk assemhly, for use
in joinin~ f:irst mol,ded pl,ast:ic tank sect,ion 101 to sccond
molde~ r~l asti c tanlc sect.ion l.o~ an~l securin-3 mc~ns for
separatin~ 107 therebetwecn. T~n~ 171 is shown in I~IC 2 to
be intec3ra,1.1,y formec~ in second mol.decl r~l,ast:i~ tarlk section
104 ancl is desiqnecl for i.nsertion i.nto sockct 170 for ~Ise in
jo;.ning first molded plastic tank section 101 and second
molded plastic tank sectlon 10~1 to~ethcr to form the
expansion tanlc fluid contailllllent vessel.
Accordinc3 to a preferred embod.i,ment of the
:invent:ion, as may be secn witl~ refcrence to l~TC. 2, socket
170 and tan~ 171 further inc.l.ude (a) t'i,r:it soc)~et sur~ace
175 and first tanq surface 17~, rcspectively, desic3ned to
accommodate tlle install,ati.on and secur,i.n~ of a portion of ~-
means for separatinc3 107 therebetween, wi,t-,h means for
separatinc3 107 bcinc3 sh.tped to fac:i.li.t.lte the encJac3ement of
a port ion of thc mean-.i for .-,cl-)arat.i.n-3 w.itl~ at least- a
portion of first socket sur.f-`.lce 175 durin-3 tanl~ asscmbly;
~ ~1
2 ~ 75~37
~, .
and (b) second socket surfacc 177 an~ second tang surface
178 respectivel.y, whi.ch when juxtaposed form stop 19~ as
shown in FIG. 3.
F~lrthermore, second socket surface 1.77 and second
tan~ surface 1.7~ are preferabl.y located in ~rox.imity to the
exterior wall of the tank (;.n relati.on to the combination of
socket 170, the portion of the means for separtting 107
being secured and tanq 171 itself, thc aforementioned
comhination ~cinq locate(l toward the inter.ior wall 190 of
tank 100). ~s w.iLl l~c ex[)l.t.inc(l hcreina~ter, tlt:is
arran~ement hel.ps form al~ ;.ntcrior lap jo;nt wh;.ch
strenqthens t~c comhinati.on of com~onents thlt ~orm the
tank.
~ dditiont:l.ly, accorclinq to further as~ects of the
i.nvention, the aforementioned joint forminq material (172)
may bc character;.~ecl as a materic-tl thAt includes a
tl)ermoplast;.c, sucll as commerciall.y thermo~l.as-t:i.c composite
mtterials forme(l .as a mixture of t~ermopl.tst;.c and metal
particles; or a wel.dinq material. wh;.cll flows ~lpon beinJ
heated. Weld coil 1~5 is shown in ~IG. 2 and ~TC. 3 as a
well known mcans ~or heating joint form:i.ng matcrial 172. One
particularly useful commerci.ally avai.l.ab].e weld;nq material
conteml~latecl hy the inVentiOIl i.s a m:ixturc of t:hermoplastic
and metal ~arti.(~l.es manl~acturc-l hy l~mabon(l (a rc-Jistcrc(l
traclem,.trk) ;ystems, a divi.sion o~ Aslllancl Chcmi.(a:l. Company.
2 1 75~37
~ urther yet, accorclin~ to a preferred embodiment
of the i.nvention, the aforemcntioned socket 170 and tan~ 171
are desi~ned such that weldinq materia1 172 deposited in
socket 170, upon beinq heated an~ u~?on beinq compressed by
socket 170 ancl tan~ 171 l~cin~ forccd to~ethcr unti1 the
aforementioned stop 1~9 is reached, flows from the point of
deposit in socket 170 away Erom stop 19~ and toward the
coml~i.nation of socket 170, thc port;.on o~ tlle mcans for
separati.n-3 107 bein~ sccured alld tanq 171., to form the
desired interior .lap joinl 1.50 del~.ictccl in ~~[C. ~.
An a1ternate cmt.)ocl;.mcnt ol~ t:hc :inverlti.on is
depicted in ~IG. 3A where an interior 1ap joint, 1~1, i5
formed that incl.udes means for sc~aratinq 107 as wel.1 ~s a
porti.on of socket 170 and tan~ 171 in thc weld. ~s
-inclicated hereinbefore, this eml~odiment i.s fcasib1c where
the means for separatin~ .is made, ~or exam~lc, ~ls;.n~ a
thermoplastic materia1 that has a me1ti.nq tcmperature that
approximates that of the tank sections (the socket 170 and
tan~ 171 portions thereof) and the wcl.cl materia1.
Thi.s arran~ement would rel.ax the nced for
di.mcnsional controls i.n the sockct and tan~ rthermore,
th;.s arr;ln~elllent woul.d cl..im;.nat-c is-;uc.-. invol.vin-J thc
coml?ression set of the (~ lra~Jln (Illeall5 l`or ~e~?arat:in-J)
mater.ia1 and the entirc ti~nk wou.l.(l I-c rccyc1cab:le without
36
2 1 7~37
havinf.3 to be taken apart j.f thc means for separatin-.3 were
made usinf.3 all recycleab~f=? mat-?rial (such as a
tllermoplastic), assumincl any air chargc was first removed.
~ ccord itlCJ to al~ altcrnate characteri~.ati.on of the
invention, a corrosion res.i.stant expansion tan)c (like t~nk
lO0 of ~IG. 1.) cnntcmplatf?~ y t~lc inventi.on comprises: (a)
a first molded plastic tank section (such as t~nk section
lOl) includinq a first tAnk connection (l.ike connection 102) .
intec3rally mol-led thcrei.n; (b) a sccond mol.dcd pl.ast;.c tank
section (sl~cl~ aci t~ k sectioll lo~), wlli.fl~ wllcn jo:;necl
togf?ther with first molclcd 1~1 a5t iC tanli section l.()l forms
tlle cxlansi.c)tl tank l.O~f) flllid cf.~ntai.llmf?llt vesse'l, inclucl.i
sccond tank connccti.on 105 :intL?-~r.ll1.y molcled thcrcin; (c)
means for separating the tank into a first intcrior port.ion
an-l a second i.nterior portion (means 107), means for
se~arat.i.nf3 1.07 bein~ secllr-?(:l }~etwcen fi.rst mold-?cl tank
secti.on lOl and second molded plastic t~nk sect:ion lO~; ~nd
(d) mcans for securinf.3 (llO) thf? mcans for separating (107)
in a joint (1.50) formecl hetween fi.rst molded t~nk section
lOl and second molded plAstic tank section lO~.
.
~ ccord;n-3 to thi.s a1ternate eml~oclimcnt of thf?
i.nventi.on, first mol.df?d plas-tic tank section l()l may he
fllrtllCr CharaL'tCri.~.ed as ~1 c3as dome wllich may hf~ connected
to ~l J~IS .';C-~lr('~ (nOt~ fwrl) via t-llf' I~ ;t: I:nlll:. L-Onnf'Ct:iC)Il
lo~ i.ntegrall.y molcled in ~.i.rst molde(l plasti.c tank section
2 ~ 75~37
101, wherein the qas dome includes a sealinq surface (shown
in part at 176 in FIC. 2); alld where second molded plastic
tank section 10~ may he further characteri~,ed as a water
dome, desi~ned to fit into the gas dome, ,which may be
connected to a water source via ttle seconc3 tank connection
105 whicl- is inte~rally mol,decl in second n-olded plastic tank
section 10~.
~ ccord.in~ to tl)i.s altcrnate character;.zation of
tlle :inventi,on, at least a port.ion o~ means for separatinq
10~ is formecl to f,it onto sealinq s~lrface 17G of the qas
dome; ancl that porti,on of mcans for separat:inq 107 is sealecl
~etween the qas dome and thc watcr dome t~y f.itt:i,nq the
aforementioned porti.on of thc means for separat.inq (10~)
into sealinc3 surracc 176 and then joinin~ the qas dome and
saicl water dome toqcther to form lap joi.nt (as shown, for
example, at 150 in ~JG. 3 or 151 in I~IC. 3~) ~y compressinq
a material tllat ;nc~ldes a ttlermoplastic, such as
commercially thermoplastic composite mater:iaJs formed as a
mixture of thermoplastic and metal particles (or some other
weldin~ material) until stol~ 199 (also shown, for example,
in FIG. 3 and FIC.-3~) is reached.
~ n alternate embodilllent of the invcntion is shown
:in rIG~ ~ wtlicll, a~ previo~sly :indicate(l, ;.s a vertical
cross-secticll view -l' an exp.-ns:ioll tanlc in wl~ich onc of ttle
fl~l;d connections to the tank :is shown molcle(l .in a difrerellt
3~
2 1 `75~37
portion of one of the tank sections. This may be observed
with reference to location ln9 in ~IG. ~. Dependinq on the
application for the expans.ion tank, it may be c1esirable to
form a ~iven fluid connecti.on at still other locations in a
tank section. FIC. ~ i5 presented ~or the p~1rpose of
illustrati.ng one way in which a ~luid connection could be
formed in tank section l.Ol, where the formation of the
connection differs from the location of connection 102 shown
in FIG. l.
~ s in(1icated herein~)e~ore, otl1er aspects of the
invention are directed to processes for cost effectively
manufact~lrin~ the tank~ contemp~.ated by the vario~1s
emhodi.ments of tlle i.nvention re~erred to hereinabove. These~
will now be described with reference to ~IG. 5 and FIC. G.
~ s previo~1sly in~3.icatcc1 ~IC. 5 depicts, in the
fo~m of a flow di.aqr~m, a sct o~ tank manufact~1rinq process
steps contemplated by an i.ll~1strative embod:iment the
invention. ~IG. 6 clepicts, in the form of a f~.ow diaqram, a
d.i~ferent set of tanh malll1fact~1rin~ process steps
contempl.ated by an alternate embodiment the invention.
In partic~1l.ar, w;.th refcrence to l;~:rc~ 5, it may be
seen that one em1~oc1.i1nent c~ tl1e i.nvention contemplates a
process for manufact:~1r.inq a corrosion resistant expansion
tan1c, comprisi.n~ tlle steps of: (a) fahricat:i.nq a fi.rst
. 39
. c 2175~37
plastic tank sect:ion that intcgrcall.y includes f.irst tank
connection me~ns (shown as stcp 201 in ~IC. 5); (b)
fabricatin~ a second plastic tank section that inte~rally
includes second tank connect:ion means (shown as step 202 in
~IG. 5); (c) insertin~ between the first plastic tank
section and the second plastic tank section means for
separatin~ t~e tank into a fi.l-st interior portion
and a second interior portion (shown as step ~03 in FIG. 5);
and (cl) joiniin~ the first plastic tank section and the
second p.last;c tanlc section w;.th tlle means for scparatin~
i.nserte(l tllcrcl~ctwccn to thcrc-~).)y form tllc cxpansion tank
fl.uid containment vessel witll the mcc~ns for scp~crc~tinq
sec~lred t~erein (shown a~ stcp 20~ :in ~IG. 5).
Further exempl~ry process steps contemplated ~y
this aspect of the invention ;.ncl~lde thc stc?ps of:
(a) inte~rally formin~ a socket in the first plastic tank
section for rece;.vinc~ the deposit of a joint forminc~
material and for receivin~ a tan~ ~ormed as part of the
second molded ~].astic tank scot:ion (tll:is is prcfera~ly done
as part of step 20~ ]~lt co~lld ~e performcd as part o~ a
separate process step); and (h) ;nte~rall.y formin~ a tanc3 in
the second moldcd plastic tank secti.on that wtlen inserted
into the socket and ~oinel therewith form the expansion tank
fluill containmcnt vcssel. (th;.s is preferahly clcne as pc~rt of
step 202 ~t co~l:ld l~e pcrformc(l clS plrt o~ a separc-lte
process step as well).
~10
: ~ 2175~37
~ eeordin~ to ~ pre~crred'embocliment of the
i,nvention the step of formin~ a soeket further eomprises the
step of formin~ a first soeket surfaee ancl the step of
forming a tan~ further comprises the step of formin~ a first
tan~ surfaee, wherein the first soeket surfaee and the first
tan~ surfaee are desi~ned to aeeommodate the insertion and
securin~ of a portion of the means for sep~rating
therebetween
~ lrthermore, accor~linq to a preferre(l emhodiment
of the invention, tlle portion of the means for separating to
be seeured is shaped to faeilltate its cn~a~ement with at
least a portion of ti~e first sock~t surfaee durin~ tank
assembly; and at least a portion of the first tan~ surfaee
is rou~hened to enhallce the ab,ility of the port;on of the
means for separatill~ to be sccurcd between the first tan~
surfaee and the first socket surface These prcferred
proeess steps are optional, but recommencled The step of
roughenin~ the first tan~ surfacc may be performed as part
of step 202 or in a separate proeess step l~he step of
shaping may be performed as part of step 203 cliscusséd
hereinabove (the insertin~ step), but al50 may bc pcrformed
in ~ separate proeess step not sllown in ~IG 5 since it i,s
optional
~11
2 ~ 7~7
`
Still further the preferred embodiment of the
invention eontemplates the followin~ manufaeturin~ steps:
(a) formin~ a second soeket surfaee and seeond tancJ surfaee
wherein the seeond soeket surfaee and the seeond tanq
surface when juxtaposed form a stop; ~b) formin~ the seeond
socket surface ancl seeond tan~ surfaee in prox;mity to the
exterior wall of the tank (in relation to the first soeket
surface and the first tanq surfaee whieh are formed in
proxim;ty to the interior wall o the tank; and (e) shapin~
tlle soeket ancl tanq sucl~ that welding material cdeposit~d in
the soeket upon bein~ he.lt:ed and ilpon l~cin~ comlressecl ~y
the soeket and tallJ ~ein~ forcecl to~ether untiL the stop is
reaehed flows from the po;nt of deposit in the ;oeket away
from the stop (toward the eom~ination of tlle soeket the
portion of the means for separatiny belncJ seeured and tang)
to form an interior 1AP jOillt. All of these steps are onee
a~ain preferably ~ormed as part of steps 201 ancl 202
diseussed hereinabove; but may }~e perEormed in separate
proeess steps as well
Iurther yet accorlin~ to a preferrecl embodiment
of the invention the first plastic tank seetion and tlle
secon~l plastlc tank section are forme~ via ~n injection
moldillJ process; alld the aforemelltiolled manufactllrin-J step
o~ joinLnq (step 20~ referred to hereil-a~ove) fllrtller
comprises the stel)s of: (a) depositin~ a we]clinq materi~l
(sucll as the aEorementioned mixt~lre of tllermoplast-ic and
~2
2175~37
met~l. particles) into the sockct; (1) he~tin~ the weld.inq
material; and (c) compressin~3 tlle }leated wcldin~ materl~l
between the socket and tan~ until the stop is rcached.
~ n alternative process for manufacturi.n~ an
expansion tank as contemplated by tl-e invention is
illustrated with reference to I~IG. 6. The ~ltern~te process
comprises the steps of: (a) fabricatinq a one piece molded
plastic ~as dome including an integrall.y formed socket
further includin~ a sealinq surf~ace and ~a5 connect.ion
(step 301 i.n FIG. 6);(~) fabricatin~ a one piecc molded
plastic water dome includ.in~ an intcJrally formcd tang and
water connection (step 302 .in IIG. G); (c) f`itt.ing a
diaphra~m onto the sealin~ surface of~ the socket (step 303
in FIG. 6); (d) deposjt.Lnc~ a wcld.in~ material into thc
socket (step 30~ in lIG. G); (e) lleatin~ thc wc~ c~
material (step 305 in FTG. G); <~nd ( r) com~ressin~ the
heated welding material l~etween the socket and tan~ until a
stop formed by tl~e sockct and tanq is reachcd (step 30G in
FIG. 6).
~ s previously stated the invention (~5
excmplified ~y tllc various ~spects ttlereof describcd
hereii~a~ove) features (when compared with the prior ~rt
lescri})c~ llereinl~cf~r.e): (a) ~.ewcr parts; (1~) f:luid
connectiolls mol(le.l int:o tllc l.ank 5C('t: i.oll'; (domc;) thlt ~/llcn
joined (t)le tanlc scctions) f-orm the conta:inmcnt vesse]
. ~3
2175~7
` ~" I
itself; (c) the use of ~lastic materials that do not require
liners or seals; (d) a diaphragm (or bladder etc.) captured
between the domes; (e) a simplified set of production
processes; (~) a tank that is corrosion resistant inside and
out; (~) a tank that does not require outside finishinq
(e.9 paintin~) ~or finisll protectiol1; and (h) a reliable
tank that can safely be utilized ~or a variety o~
applications includin~ water stora~e applic~tions and high
prcssure environments due to the inhcrent stren~th of
thc la~ joint formed usin~ the process clcscribed
hereinbefore
What has been described in deta i.l hereil1above re
methods a~paratus and fahrication tccl1niques wh.ich meet all
of thc aforestatecl objectives. As previously inc1icatc~1
those skille~ in the art will reco~Jnize that the foreqoin~
description has been prescntcd for thc sake o illustration
and description only It is not intel1dcd to be exhaustive
or to limit the invention to the precise ~orm disclosed and
obviously many modi~ications and variations are ~ossibl~ in
li~l1t of the above teachin~
The embodime11ts and examples sct forth herein were
presente~ in or(ler to ~est exl~]ain the ~rinciples of the
instant invcntion al1c1 its practic11 app]ic1tion to thcreby
enable ot1~ers skilled in the art to ~cst utilize the in~tant
invel-tiol1 in various e1nbodin1cnts and with various
2~ 75~37
modifications as are suited to tlle particular U5e
contemplated.
In view of the above it is, therefore, to be
unde~stood that the claims appen~cd hereto arc ;ntcnded to
cover all such mo~lfications and variations which fall
within the true scope and spirit of the invention.
~5
