[1]Patented Feb. 23, 1954 2 9 6 6 9 9 9 4 1 UNITED STATES PATENT OPFICE 2,669,941 CONT]INUOUS LIQUID PUMPING SYSTEM John W. Stafford, Hohokus, N. J. Applicatioit December 15, 1949, Serial No. 133,119 6 Claims. (Cl.,103-241) 2@ This invention relates t6'a:new drid improved continuously operative liquid pumping system of thb type making use of two tanks which are filled alternately with liquid from a common supply line and are discharged under gas pressu I re into 5 a common discharge Iiiie so as to maintbin a continuous flow of liquid through the latter. Such a pumping system finds valuable industrial uses, for example, in delivering sugar juice treated with a decolorizing medium through -L-ilters iinder a @16 pressure best suited for the filter operation. A pumping system of the type mentioned '@s known in-wbich the discharging and refilling of the respective tanks are eff ectuated automatically by the action of floats in the tanks, vrhich operate i5 slide valves on air intakes and vents of the respective tanlcs secuentially through interconnecting mechanical linkages so as to cut off the pumping air pressure from one tank and vent it simultaneously at a lower limit of moveinent of,the @2o float therein, after admitting compressed air to the other tank to start pumping from it, and so as to close the vent of either tank a@t An upper limit of movement of the floblt therein. -See 2 5 United States Patent N6. 2,093,474. In that known system complex m;@chanical const,,,uctioiis are requi@ed which @limit the serviceability of the syst-.m and are costly@ to manufactiire. An object of th6 present invention is @to provide a system of the type mentioned wherein:only simple mechanical constructiong aro. utilized at the two tanks, and in which control of the steps of operation may be 6ffectuated through control mechanism remote from the tanks themselves. Another objeft -is to -orovide a continuous pumping system which alvj,.iys maintains a steady '@low of liquid under an even pressuie, with6ut objectionable surges of pressu-,-,e in the discharo;e line. According to bne feature of this invention, tWO @46 tanks adapted for a sYst6m of@the typ,-@ m6n@ tioned are ench provide,@l with a 'cbmioressdd 'e@ir intake and P. vent respe-,tively having electrically a,ctuated valves for opening and closing the same, and thes-, valves are operated @throiigh;elect@ical 4@ cbntrol rneelianisni awa@y from the tarilcg--in.@'re@ sponse tb liciuid level re@sponsive motivating ele' meiits located ,it fix--d upper and lower positions ins - ide eacb- tank, -b a@ to ma,,'@r-tain 9 continuous fiow of liqui-d from Lhe t-anks through a common 50 liouid discharge line. Ac@ording tb ailbth6j@: f Oatiire 6f the preseht'invp-ht@.0n, it iias beph7 foui-id @ tl-iat 6biecti6nable 30 op'erating air intakb@ and'vent val,@es- on@ the"re@spective tanks so that the v6nt of a tank iiearihg the end of its pumping 6peration is kept closed:for a predetermined interval afte@ the closing of,-the compressed air intake of this tank, and @o,tha@t, at the time of such closing, th6 other tank,hasr@its vent closed and its compressed air intake.6pen6d to begin its pumping ope@ation. In this'way,-the full Pressure of the air supply is always@,biaing admitted to one or the oth6@ of the two tanks I and a tank from which the compressed air@suppl@ has just been cut off contin@ibs neverthel6ss@to'disdharge liquid under its internal air pr@ssure-.@for an interval during which the full@ pumpiiig pres.sure is being built up: in: the @other @ tAnk.'' @k, s3fstem embodying this impr6ved op6ration may@-,,be obtained by providing adjustabl eLtiine@dblay...relays among automatic switch 'units inciuded@ in the electrical 'control mechanism :Above.- @mentioned. I The foregbing and dthOr,objectsllfeatur.Os and advantages of this iiivention will@ be;@e@pparent from the@following detailed description@@and,,-,the accompanying drawings of a-@preferred@-emb6di@ ment theredf, while the structiires'or" coriibina tions and operations regarded Eis th&, invention will be defined in the appended claims-. iri the drawiilgs Fig. I is a schematic vii@w of m,@ @ continuous pumping @ system, showing the:twb tanks iii.vertical cros@ section dnd showin@ the, connect6d electrical control mechanisin in diagiarff @.,.ori' a separate panel; @'Fig. 2 is an enlatged wiring2 diagre@in indi6olting thia-functions and intetconnections'@of uriits 'bf the control mechanism-. As seen in @ Fig. 11 :the system here !provided makes use of two tanks@ A and B in side by@ side arrangement. From the bdttonis ;f'a@ i'ai-id@@llb;of these tanks: extend discharge coiiduit@'@ 2a"'bjad,.2b, respectively, and liquid feed conduits 3d and'3b, respectively. The discharg6 cbndilits C'Oiitiiiii check valves 4a and 4b, respectively, wlii6li'-6@6n only iii the directi6ns away fkbni the besrorid the e dhedk,@Al-@e the tw'o di@c@harge c(induits jbin ',*ith a commbh discha@gb'-rliiie" 8"" by which'the liquid pumped froiii the syst6 -is carried to a filter @ress 6.t otiie,r @oiiit; of "tkegtment or use. k The liquid feed conduits conte@in chee vi@ives 6d'and 6b, respectively, *hich olien oill@@@ln@'-the directions tbwatd'the@ re@pectiv6@ tbnk 'A iirid, B, 6,nd: bey d th6@ e dh'edk'v@,lveg the -t d 66hdiiits on o, pressure;in the @di@charg6'linle'oi With@ 'e@ commoii -li4iiid@ fded@ lirib, 7 @*-hibh',extem- of the tY@e mentioned iiiay bi@ @avoicled by 55 'terids. froni - @t: -source I of feed llq'u''id@- 16datdd aV6ve,
[2]3 the pumping system so that the hydrostatic pressure of liquid in the feed line will produce flow through the check valve 6a or 6b, to :ftll the corresponding tank, when the tank is vented or free from counteracting internal pressure. At the tops I Oa and I Ob of the respective tamlcs there are single air conduits I I a and I I b which have divergent branches 12a and 13a, and 12b and 13b, respectively. The branches 12a and 12b carry electrlcaliy abtuated -@AIVOs 14d And 147b and are vented to the titmosphete beyotid the8e valves. The branches 13a and 13b carry electrically actuated valves 15a and 15b, and beyond these valves they are connected to a ro=.un compressed air supply line 16. Accordingly, the branch conduits 12a and 12b constitute Vefitt bf the respective tanks, which are closed when the respective valves 14a and 14b are closed; anci the branch conduits 13a and 13b comtltut!Li ttir intakes of the respecti,06 tanks, through which compressed airpasses int-o the tops of the tanks whien the respect-ive intakevalves I @a and 4 Sb are open. It results t-hat when. liq@u,'i@d it present in either tank and tho iritake vblv-e of that tank is opell, its vent being tlosed, the preMreiDf the compres@3ed air sUppl5t will for0e the hqu-id through the @cheek valvi3 4a @or 4b of the cotrespondmg liquid discharge conduit 2-a or 2b, and thence into and through the tommon disoharge line 8. Any suitable forih -of elt-ctrically aotusited valves m.iy be used at 14-a-i 14b@, I 5a qnd f Bb. iilustrated and prefeirrtd for this purpose are notmary closed solenoid Valves -*hit-h niove to clien pogition when energized eleetrically itnd move to (@losed positit)n, when deenergi2td, under the influence of springs in the 'valvl- unita. Loc6,ted at fixed tipplr and lowlr pcisitiofts inside tarik A @At-e liqui@d levdl reslionsemotivating elements 2 Oa and 2 4 aj Which in this einbodimefrt are electrically energized probes respongivo 'to the electrical co-irduetlVfty of liqttid conta-eting the probes. F'6r exazhple, they i-tay be prbbe ele, ments of the comrherei'al produet knotn qs a "Ph6toswitch Level Control Type 10CB1 Sitnilarly located inside t6,nk B ate sirailar eletie-nts 20b and 2 lb. Tht- elements 2#tt and 20b inay tre suspended in th6it tlesirl-d pbgitiong, doeiidihg upon the limit desired for the high Itvtl of li-quid in each tank, bY rodg or wires 22a and 22b L-xtending fron! fittingt 23a and 2 3b in tht tops Df the respective tariksi and the leltments 21a a-Ad 2 lb may be suspended siiiiiIaTISr by lorig rods or wires 24a and 24b from fittings 25a aftd 25b. Instead of the particular elefnents shown tlny other suitable type of fixod elem4ents mty bt- used that will serve to establish tliffererrt electiidal circuit conditions tiecordhig to Vhether they gre exposed above or are immezsed in the iiiltu,d in the tank they serve. As seen in theupper part of Mg- 1, an, electrw. Ea control mechanism indicated generally at 3@0 is provi @ded on a panel 31 loeated away, fromthe tanks A and B at anysuitable, place. Tlxe, severe@l electr,ically actuated valves. as well, as, the soveral liquid level responsive, motivabmg elements are connected with this, mechanism,, which is Organized so as to operate the valves sequentiOIIY in response to changes of liquid level affectirK the motivating eiements in each tank. In general, the. electricalcontrolmechanislm 30 comprises automatic switch um.ts for the respective vent valves 44a and 14b, whicil deeno,gize and tlius close.. the vent valve -of ath4E@ _ t= r ._k in response to contact of, the liquid level In such tank with the upper motivating element 2ft or 7@ t o A a,4;1 2 2,669,941 20b therein; together with further automatic switch units actuated through exposure of the lower motivating element 2 1 a or 2 1 b of either tank, to close the air intake valve 15a or 15b of the same tank and simultaneously open the other air intake valve, and to cause delayed opening of the vent valve 14a or 14b of the same tank. For the last mentioned purpose and in order to prevent surges of pressure in the discharge line 10 9, ihotei ftrth@r- tinits iftelu,,de titne-deloy relays eoiihedted With the resj)tctive Vetit valv@s to hold the vent valve of either tank closed for a predetermined interval after the closing of the air intake valve 'Of the same tank and the opening id of the air intake of the other tank, and to open the 8athe #,6nt valve at the end of that interval so that the corr-es-ponding tank then begins to refill fkom the liqiiid feed line 7. Far-ther, the electrical control mechanism may 20 also include a manual switch station having a icentaet element movable manually on an-d off to -energize and ideenergize the automatic switch metns, th-e on movement @serving at the start of use of the s3rstem to cause both tanks A and B 25 to be filled from the feed line until their upper probe elements 20a and 2-Ob are covered to -close their vent valves 14a and 14b,. and another con tact ;element at the manual switch station is movable manua@lly thereafter to open the air 30 intake valve of one tank a;nd thus start the pumpingopefbtions. Manualconta@ctsor,pushbuttons doftnected to function in thir, way may be provided not -ofily at the control panel $I but, also, if deslired, at ttny conve @mentlocat-ion remote from 35 the panel, for example, at a, filt-er sta;tion to which hquid U puniped by the contiiiuous pumping systeM where it ma-y be desired to discontinue or resi=e the operation of the purnping system. Rdfe:rriug ihore part-icularly to F-ig. 2, which 40 tho*s details of the Eissornbly 30 of Fig. 1, there are fotir 1evel control telays Al, A2, B-1 and B2 connected tledtrirally with respective probe eleMP-nts inside tht twO tonks. Each such relay mOy be of 'the type dmignated commercially as 45 a "Photoswitch L6vdl Control Type 10CBI" which, funda-ment6,lly, is An altemating current control that:eombine@ u. J)rcibe circuit and transformer iT-l a Ma'nner to operate u @direct current relay through a rectifier. Closure of the probe circuit 50 ELiters th-e mag@'netic fielcl of the tralisformer in sdeh.a wiy that current is generated in the rectifier-relay circuit to energize t-he relay. ih additiob, there itre two silnple relays RA and RB and two tiine delay telayg TA and TB. The 55 tirhe deloy re'lay8 inqy be of any suitable type wheteby desited circuit changes can be effected within a few seconds after energizing either relay, the t,-=edelay depending on the setting selected. These r6lays conveniently are of a ty.De 60 knt)wn , comMeroitLIly by the name "Agastat," wherein delayed switch contact movement is obtai-ned by bleeding ait through an adjustable ii&edle valve from a beuows moved by the relay arm., 6.5 Alternating eurrent for energlzing the various conttol olernents is supplied t-hrough lines LI and L2 from a suitable source of _power when a master switch M irx these lines is closed. Line LI leads thrgugh contacts of a pushbutton marked "On" 70 to the coils of the various relays or automatic switch elements. Line L2 leads direetly to one terminal of each of the vent. valves 1.4a and 14b, to ebil terminals. 2 alid cantaqts 4 of level controls Al and and. to, coil termina-Is 2 of le' vel con The "On!' button contacts
[3]which 6hergize the- various @rela'ys, m, ay be-o'p , eri@d to deen6rgize therri by pressiiig iin @ "Off" pushbutton. A "Reset" pushbutton also ig prdvided in connection with an air vblve of one tank, say valve 15b, and with a corresponding level control, such as contact 5 of control B i, for movement to start pumping operations after the tanks A al-id B have been filled. Level control AI is connected with both probes in tank A, as indicated in the diagram. It acts to hold contact Al-4 'mterconnected with either contact Al-3 or contact Al-5, depend'mg upon whether the liquid level in tank A is low, or high, i. e., whether the two prob6s 2 Od and 2 la ake exposed or immersed. When these tw6 t)robes are iinmersed, L@ current passes through Al con-t@cts 4 and 5 to contact 3 of control B2 aiid to a ii6@mally open contaot of relay RA. The otbe-r normally open RA contact is connected to ori6 t@rminal of the air valve 15a of tank A and to one te@n-iinal of the RA relay coils. Wh6n the two 'probes in tank A are e%posed,' L2 cur@ent 'p@isses through AI colitdcts 4 and 3 to the coil of tim6r TA, thus energizing the 1.@itter so that it proceeds after a predetermined interval, say two @@6'cor@ds, to bpen normally closed contacts TA-21 bnd to close normally 6pen cbntacts TA-1 'whereby Li current is relayed to the vent valve of tank A to energize and open that valve. Level control Bi has similar coniiect-lons with the two prbbes of tank B, and it abts at the lo@v and high level condition.@ in, tank:B@,in the way described with roference to contr6l Al, tank A and relays RA and TA, so as to furni- h L2 c,,irreht TB or thro-ugh coiitact-BI-5 to contact 4 of cb'ntrol A2 and to a normally opeil coiitact of'@6lay RB@ Wheii-@ TB is energi-@ed it 1@r6ce6d@ after a predetermiiied time delay, sdy: of two sbconds, to . riormally open contacts TB-1 leading t6 the'@6iit @alve of tank B@ Level c6nt@ol A2 is c6nnected ivith the @lon@ier probe 2 la in tank A, and level control B2 is cohiiectedwiththelov@eri@r6b621bintankB. Wh6l-,l either of these probes is exp6sed the cories@biiding control A2 o@ B2 iritercohiibcts it conteidts 3 and 4. thereb@i ti@thsnlitting L2 durrett t6 the air valve 15b or [5a and thb iioid'mgr@l@y'@l@B or RA of the other o r I non-corres . ponditig@tarik (assuming that, the bth6r t@Liik is then full s6 that conta,.,ts 4 and 5 6f its 16vel control BI-' or-'Al',, as tiie case may be are then iiit6kconne6tedY. The dele@iled operatioii df the system @thekofo@e is asfollo*s. Tanks A and B beihg empt@r, bnd it bein@ desired to start c6ntiniioiis 'pumping o@erb@tibiis from a supply of liquid presel'it, iii and 'abbve feed line 7, an opers@tor first elbsesmaster stitch Y- I to - deliver curr6nt to the control me6hanism @'60 and tl-dn i)us-hes' th6 '@On" buttb@i'to 'energize timers TA ai-id TB whi;ch act @fte@ 'an'irite . kval to blo@e conta:ct,@ Tik@ I and TB--@ I a-hd -ihu@ eiie'rgize and opbil thb tw6 @6nt valvi3g 14d @ and 'I 4b. TI@@ t@irrers'ar6-thii@ bil-ergized diri@dtl@V becAtiE@e, ix7it'-Pi the pr6bbs in both:tank@ e@:po-s'ed" the;;'coil -V of A recei es L2 ciirront thtough A I tontacts 3 @nd 4 and th6 cbil bf TB roceives @ L2 cut't'ett through BI contacts 3 and 4. Under the hydrostatic pressur(@ in lirie 7 liqiild flows thi@bugh@ tho check valves 6d -and 'Ob'into tank,s A and @B, until ebbh tank' has,: bee@n' @filldd to @a higli leV61'thi@re prdb6Ei@-clotes tir@6 1--ithd4 @6rid intdrcohn ects@itsi @dontacts 41 ind, 5, 6,nd thb sam' & bctioriocc urs@@iii level,cont rol BI; so reldys, TA aiid TB@-are deenergi zed and the v.;ent val@ves 14a afid 14b cl,ose to stop the liquid .5 infidw. Meanwhil o, the@cont acts 3 and;4 of level control@' A2: and B2 are. also disconnec ted 9,xid cdiitacts 4'and 5 of these controls are connecti3 d in - re@poii@ 6 to the ri86 of liquid above the lower pfobe in t!Ach,- tbnk. 10 The tanks' thus@ having been filled, the operatO r now presses the "Reset" button:to start the contiriu ous pumping operatio ns, which begin frbnl @ tank B. At this time the air valve 15b of titrik B is - supplied with Li current throiigh the 15 - ,norinall y closed TB contacts 2, and the "Reset" button:- c6ntact @ deliver to the same valve L2 current transmitt ed through Bi contacts 4 and 5 which,,': beceime intercon nected wh6n tank B became ; full.-' ThO : ."Reset" button acts in20 stant aneo usly to com pleto %a circu it thioug h contact @ : 4 aiid 5 bf cont r6l B I to @ the cbil of rela y RB, so that the latter beco mes ener gize d to hold vdlv e 15b ener gize d ihro ugh a circu it inclu ding cont acts @R BI. Mov eine I nt of "Res et" ther eafte r 25 has no effect. With the admission of cbmpress ed dirthrough valve 156, the liquid in tank B is forced out thtough,- cheek valve 4b and the disObqrg 6 liii6 8; io-the fi'ltie'r'@p tess or other place 6f liquid:trea tment. Meanwhil e, taiik A stands idle but full and ready for use. When the liquid in to@nk B falls below the lower probe 1.2b, therein, thL, air valve @l 5a of @tank A is' bperied'immediately to start puniping liquid from tank A, the air valve 15b of tank B is closed either through contact Bl---3 to energize time]@ 35 immediately, biid the'timer TB move@ to open tho v6nt:val've 14'b of tank B only after the desired@ time deloy. Upon the openiiig of vent valve 14b tank B @p'roceeds' t6 re@fill from line 7 as the l@iquid in: taiak -A is'being pumped out through open normally closed coiitbcts TB@2 and to elbse@'@-4i) Iiii6, 8.@ @The'exp6:@ujre of ifie tarik@B'pr6b--s bkings @allout,these ch.@'nkeg by' @:i2Ausing level 'controls B n-d B2 I @ @a - to, dis co nn' ect ' the ir @r es p6 eti ve 4 an d 5 'C olit act, @: An d I sini Ult @r leo @ usl y'i nte rco nn ect thb ir res pe cti vti 3 @ ah d 4: co' nta I cts. ' Th e di8 co nn ect ion Of B I @c orit act 8 4 an d 5 de en er giz es rel ay RB wh ich im me dia tel y op 6ns ,co rit @a cts RB -1 @t o de' en er giz e 'an d cl,6 @t: the @' aii7 l Val ve of @ tqii k' B. Th e irte rco nh 6et ion of 'B I cdi itb ctg @3 - an d @ 4' eri er @i ze s rel a@ r TB ,,w hic h 'act s @ @f f6r twc i 'se co,id, @,l for ex aihpl e, to 6lo se cor it@ cts TB -1 an d thu s 6n er giz b - an d: o @ on the @ ve ryt: val ve@ of tan k B. Th e int e @c oni i6ct idn of B2' co nta cts 3 an d @ 4 imr @i edi ate ly en er giz es @: 6,n do pe ns the aii val v& bf tan ',A (si nc 6 tha t'va lve @i @: alr ea @ dy @ ec eiv in @ LI: cur i @r ert thr oii gh tlie @ no rm bll y clo se d 6o nta cts TA an d this , Als 6 en er giz es rel ay RA : s6't hat it for ins a holdi ng:ci reiiit. dire ctly,t 6 thi@ airva lv6 of to@i ik A,fr om contl iet 5 of cont rol Al. The liquid@r-ising@iri tank.B'ndrmqlly readhes the high level therein, where probe 20b makes contacts, before tank A is einptied. Thb Vent valve 14b of tarik,B;then closes immediately, since contfol BI tli-en 'dep-nergizes dontact B 1-3 @Lncl"relay TB t6 d6etiergize the veiit valve. , Al65@ thoiigh relay 'T]3, 6loses -contacts TB-2 at this time, the do'nne'eti3,,t air vz@,live of @ tanl@i B, Ls no@ u onergized@ beca' se: the lo,,@er probe i n tank A has yet to be exposed sd:gs to connect contacts 3 and 4 of control A2. S 11 o tO I nk A continues pumping 70 whil6 tank B staiids full and ready to pur-1p. When th6 lower:: prolie 2 1 a I in tank A is expo@ect, coiltrol A2 iriterconnects it8 contactg 3 and @4, - ,th6reby'energiziri'g' and opening the @a'lr cuit by contact with the liquid.--@Level cbritr@ol.., v@alve 15b!, 6f't6nk @B- to i@tart'pumi$in@ @ fro@-n: @th6t .Al:then opens' the @'eircuit, @thf6u'gh it8 dont@acts @d. tank@'. @ -At: tho-r 8ame@;,time'l-leve'l 'e6ntrol Al@ 7-dis-
[4]co,nneots Its; icontaicts 4'and 5 and Sim aneous.. ui@ ly interconnects its contacts 3 and 4i with the effect of immediately deenergizing RA and the air valve of tank A and energizing time relay TA, thus causing TA to energize and open the vent valve of tank A only after the preset time interval So the pumping now proceeds from tank B, and after delivery from this tank is under way pressure is vented from tank A and it starts refilling from the supply line 7 through check valve Ga. By reason of the maintenance of internal gas pressure in an emptied tank during the interval set by the time delay relay, liquid continues to flow out of that tank and no objectionable surges occur in the liquid delivery line 8 as the other tank takes over the pumping work. As described above in reference to tank B, tank A reffils completely before tank B is empty. When the liquid in tank A makes contact with the upper probe 20a, level control Al interconn,ects its 4 and 5 contacts instead of its 4 and 3 contacts, thereby deenergizing relay TA to close the vent valve 14a of tank A immediately, and supplying L2 current to contacts of level control B2 and relay RA so that the latter are in readiness to open and hold open the air valve 15a cf tank A when B2 contacts 4 and 3 becomes connected in'response to exposure of the lower probe 2 lb in tank B. The exposure of that probe thus produces immediate pumping from refilled tank A and, in a.ddition, energizes relay TB through interconnected B i contacts 4 and 3 so as to deenergize and close the air valve 15b of tank B immediately and to ea-use delayed opening of the vent valve 14b of tank B. Pumping thus proceeds from tank A while tank B is refilled. Accordingly, as each tank becomes empty the other tank stands refilled and immediately takes over the pumping work, and thus a continuous a,nd even flow of liquid is maintainod through the delivery line 8 under the air pressure established in air line 16. The system continues op-erating (assuming an unlimited supply of feed liquid from line 7) iintil such time as an interruption may be desired. At that time the operator. simply pushes the. "Off " button, which deenergizes and closes all the air and vent valves so that no further flow of liquid will occur. The pumping operations inay be resumed at any tinie, however, by simply pushing the "on" button to reestablish valve opening circuits. It will be undergtood that various alterations n@nd substitutions may be made in details: or elemetits of the eriibodiment described above and illustrated in the drawings without dei)atting from the new features of construction and operation herein disclosed and claimed as my invention. I
