CHEMICAL
6 M E T A L L U R G I C A L
ENGINEERING
ESTABLISHED 1902 S, d . KIRKPATRICK, E ditor
OCTOBER, 1940
M AKE HASTE SLOWLY
HAT E W E R E LA TE in getting started with our re-arm am ent program . A lready there is mounting pressure on the p a rt of the public to show results.
A lready there is a great tem ptation to rush head
long into a frenzied drive for production—a process th a t may well lead to dire consequences.
Increased output m ust not be gained a t the ex
pense of health and safety. Multiple shifts and overtime work will often be necessary to meet the demands being p u t on industry but we m ust not lose sight of the fact th at there is a lim it to human endurance. The B ritish H ealth of Munitions W ork
ers Committee has shown th a t the rate of output per man falls off rapidly as the proportion of over
time increases. Nor are engineers and plant execu
tives exempt from damage to health and efficiency through overwork. Such men, who must give them
selves unstintingly to their jobs, are not readily replaceable. The best interests of the national defense program demand th a t man-power be con
served if our industries are to m aintain high pro
ductivity.
There is a second and more startling consequence of haste which m ust constantly be in our minds.
Serious p lan t accidents th a t result in great losses of life and property are all too frequent in pei’iods of emergency. W ithin the past few weeks we have witnessed a t least one m ajor disaster and several m inor ones th a t have taken an unprecedented toll of fatalities from among the employees of chemical industry. The p rim ary causes of these accidents may never be determined but it would be eminently u n fair to the companies and governmental agencies involved to imply th a t any lack of safety precau
tions was a contributing factor. These plants and arsenals were built and operated in accordance with the best knowledge and experience of men who are
recognized leaders in our profession. In extending our sympathies to those who have suffered these great losses, let us resolve to help in every way we can to prevent the recurrence of any tragedies of a sim ilar nature.
Chemical industry has set some enviable records in accident prevention during recent years. In 1939 it ranked seventh in frequency and seven
teenth in severity of accidents among the th irty m ajor industries charted annually by the National Safety Council. This progress has been made be
cause the industry thoroughly believes in safety and has gradually developed the knowledge and skill to protect its workmen against its inherent hazards as well as those common to all of industry.
These statistical records will now suffer a tem
porary setback as a result of the recent casualties but the basic safety work of the industry m ust be renewed with redoubled energies.
Finally, quite a p a rt from human hazards, is the rather obvious futility of trying to move too fast with new technical developments. One reason for the sound growth of chemical industry, which is almost unique among industries, is the standard chemical engineering sequence of laboratory-to- pilot-plant-to-commercial-production. E xtrao rd i
nary defense needs may prove a tem ptation to skip steps in th at process, to rush into even larger units without necessary knowledge and experience. B ut it is im portant to remember th at we cannot now afford to build any more inoperable chemical plants like some the Armistice saved in 1918. Nor do we want any white elephants of surplus capacity and obsolete equipment to plague the industry when this emergency is over.
F o r all these reasons, and others you can easily
deduee, we say, “ Make haste slowly—and safely!”
FIGHTING THE SABOTEUR
Re c e n t e x p l o s i o n s
and fires in plants of the process
industries again spotlight a serious problem which every division of industry must face if it p artici
pates directly or indirectly in defense measures.
Here is a twofold responsibility: F irs t to take the necessary precautions against accidents from hum an and equipm ent failure and second, to p re
vent the opportunity and chance of willful damage.
In this latte r responsibility, the D epartm ent of Justice is ready to aid. I t has specially trained men in its sabotage prevention squads who will assist industries in making surveys of men, m eth
ods and equipment. A ny plant th a t does not feel thoroughly certain of its own precautions can se
cure cooperation by addressing the Federal Bureau of Investigation in W ashington w ith respect to any undertaking having importance from the national defense. There m ay be a num ber of cases where this skilled and strictly confidential coopera
tion may be needed. Chemical industries should not hesitate to ask for it where such need is evident.
MAKINGS OF GOOD INSPECTORS
A n e x p e r i e n c e d c h e m i c a l e n g i n e e r,
whose modesty prevents our use of his name, has w ritten of some of his experiences in American explosives plants during W orld W ar I. We had asked his opinion about the need for chemically trained in
spectors. “ There is no question,” he said, “ about the necessity for having inspection work stem from w ithin the service. Outside efforts would only add to confusion . . . I recall with some sadness a pathetic condition a t the ... p lan t during 1917-18. The personnel departm ent at W ashing
ton had sent us three young men as inspectors.
None of these had ever seen smokeless powder be
fore and they were n aturally scared stiff. The superintendent was having his troubles with the labor gang, so I had to take the boys over myself.
Ended up by placing them in the laboratory where they remained for the duration of the war. U nder no circumstances were they cut out to be in
spectors. ’ ’
F R O M AN
“ In my opinion here are some of the qualifica
tions th a t good inspectors should h a v e :
(a) O utstanding loyalty to the country, above bribery and knowing something about discipline, preferably as a result of service training.
(b) Knowledge of men plus some experience in handling skilled labor. Rejection of m aterial may play havoc not only with production but with morale.
(c) Chemically-minded, yes, and m etallurgi- cally minded too, b ut of even greater importance is to be endowed w ith an awareness of the simple principles of science.”
In conclusion our friend adds a thought th a t can well be pondered by all of u s : “ When we get into the war game, we are in a grim y business. I t de
mands real men w ith character as well as initia
tive.”
AMMONIA VS. NITRE
W h e n t h e p r e s e n t e m e r g e n c y
has passed there
may be from 50 to 100 per cent more capacity for ammonia synthesis in the U nited States th an can be used on peace-time activities. Some of this will be government-owned equipm ent in plants th a t p re sumably are to become strictly standby defense units. B u t some of the surplus will be owned by big chemical enterprises. A t least the la tte r will represent a potentiality of surplus production th at is already w orrying some executives.
I f the present m ilitary program is expanded to provide capacity to service 4 million men under arms, as W ashington now talks, there will be still greater demands for ammonia or n itric acid. Re
cently i t has been suggested th a t this fu rth e r increase be accomplished by use of Chilean n itra te rath er than by building more ammonia-oxidation capacity. This proposal has three real merits.
I t would eliminate the th re a t of greater idle su r
plus ammonia capacity. I t would perm it neces
sary production of n itric acid with less immediate new capital investm ent by the government. It would give Chile a m arket for some of the n itrate which th a t nation now finds difficulty in selling elsewhere.
There can be no simple generalization as to
“ the best p la n ” fo r such complicated circumstances as are now being met. B u t chemical engineers will be wise in avoiding the hasty conclusion th a t there is no justification for re tu rn to the old n itre pot
672 O C T O B E R 191,0 • C H EM IC A L & M ET A L L U R G IC A L E N G IN E E R IN G
E D IT O R IA L V IE W P O IN T
to meet the prospective demands of explosives m anufacture. Such warning is probably not amiss ju st now when this question m ust be settled with one eye on the diplomatic consequences in Chili while the other is looking out for a cheap and ready source of needed n itric acid.
WHAT OF THE AFTERMATH?
E v e r y u n j u s t i f i a b l e r i s e
in prices brings us th at
much n earer to a peak from which descent is almost sure to prove disastrous. We need only go back to the history of chemical prices during W orld
■ - W ar I to recall the dizzy heights reached in that period of inflation. And anyone who had to liqui
date high-cost inventories in 1920 and 1921 a t ten cents or less on the 1919 dollar, knows how ru th less were the processes of deflation. This time, if a t all possible, we w ant to avoid th at terrible ordeal.
I t is probably inevitable th at some prices will rise. In a num ber of cases there may be adequate justification. B ut if this country is going to escape governmental control and the type of price-fixing th at has been forced on all the w arring nations of Europe, it is time th a t all industries try their best to forego reckless and unjustifiable increases.
Chemical industry has already shown its desire for stability a t fair-profit levels. L et us hope we can continue on th a t course during this emergency.
PREPARING FOR CONSCRIPTION
Ne w s
th a t chemical plan t employees will not be exempted as a group from m ilitary service has been received with surprise in some quarters. Even though a chemical plan t is an essential industry working on Government orders, the law expressly forbids any wholesale exemption of technical men.
Each case will be decided individually. Actually
“ exem ption” is not a good word to use in this sense.
“ D eferm ent” is the proper term.
Employers should note this im portant point because it means a number of things to them. They can never be certain th at key employees will not be drafted six months hence so they are therefore allowed b ut six months to tra in substitutes. I t thus becomes essential for every employer to take stock of his personnel. He should determine which men are most likely to be drafted and should make arrangem ents for replacements. In cases where replacem ent is very difficult or impossible, the
employer should be prepared to apply to the local d ra ft board for deferment of service for such individuals. I t has been adm itted by Government spokesmen th at employers’ applications are likely to receive greater consideration than employees’.
There is, however, no occasion for immediate alarm. I t seems unlikely th at the first draftees will be inducted into service before December 1. Mean
while employers have an opportunity to form ulate their policies in regard to m ilitary service. They are not required to “ guarantee” the employee a job after his period of service; however, they must show ju st cause for not doing so. Many companies in the chemical industries have already announced policies of aiding the draftees in other ways as well.
Most of them will m aintain group insurance premiums. M any will pay the draftee two, three or four weeks’ pay upon his induction. Some have even volunteered to make up the difference between Arm y pay and his form er salary. A few have offered to contribute to the support of the d ra fte e ’s fam ily in case a m arried man should be drafted ; however, it is improbable th at men with dependents will be'drafted in the present program.
Employers who show willingness to cooperate by adopting some of these policies will probably receive preferential treatm ent in their applications for deferment.
THE WATCHED POT
Li k e t h e p r o v e r b i a l w a t c i i e d p o t,
the national
defense program seems as though it will never boil-— at least th a t’s the way the general public probably views the situation. Actual deliveries of warships, guns and explosives are still a long way off. B ut all this only proves th a t getting ready for a big m ilitary program takes time.
I t is going to be a responsibility of m any chemi
cal process industries to take some p a rt in ex
plaining this situation to outside critics. Some delays seem inexcusable. Others represent inevit
able time factors. There is an opportunity for cooperation between those of us who should under
stand the difference and the m any outside of the industry who do not. We are a bit more likely to be believed when we say th at it takes a full year to build a large explosives plan t or even longer to complete research, development and final m anufacture of an entirely new product for which new processes and equipment are necessary.
CH EM IC A L & M ETA LLU R G IC A L E N G IN E E R IN G • OCTO BER 191,0 • 873
M a k in g A lu m ina a t M o b ile
JAMES A . LEE
M a n a g in g E ditor C h e m ic a l & M e ta llu r g ic a l E n g in eerin g• C fiem . & M e t. I N T E R P R E T A T I O N " ■
This is an u n u su ally splendid exam ple of straight-line flow of m aterials, the raw m aterials entering at one end an d the finished alum ina lea v in g from the other. The layou t differs from that u su ally seen . Here production is lim ited to a sin g le product, and that is m ad e in such an enorm ous volum e that it is m ost efficient to h ouse ea c h step in the p rocess in an individual building.
B ecause of the trem endous volum e of m aterials that must b e h and led con v eyin g equipm ent h a s p la y e d an im
portant part in this great plant.
— E ditors.O
NE OF T H E GREAT N EW C H EM ICAL p l a n t s th a t is p la y in g an im p o rta n t p a r t in in d u stria liz in g the h eretofore a g ric u ltu ra l South is th a t o f the A lum inum Ore C om pany, a su b sid iary o f the A lum inum Com
p a n y o f A m erica, a t Mobile, A la.
M any o f th e p la n ts are being located a t the source o f the raw m aterials of which the southern states have been so a b u n d a n tly su p p lied by n a tu r e ; however, in this case the p la n t site w as chosen a t the P o rt o f Mobile because of its accessibility to the C om pany’s sh ip s b rin g in g the raw m aterial, bauxite, direct fro m de
po sits across the G ulf o f Mexieo.
The op eratio n s o f the p la n t were plan n ed so as to take fu ll adv an tag e o f straig h t-lin e flow o f m aterials, the raw m aterials en terin g a t one end and the finished p ro d u ct leaving fro m the other.
The la y o u t differs fro m th a t usually seen. H e re p ro d u ctio n is lim ited to B auxite from Surinam is u n lo a d e d a l the M obile plan t
of the A lum inum C om p an y of A m erica s h o w n a b o v e
C74 O C TO B E R 1940 • C H EM ICA L & M E T A L L U R G IC A L E N G IN E E R IN G
a single pro d u ct, and th a t is m ade in such an enorm ous volume th a t it is most efficient to house each ste p in the process in an individual building.
A p la n t site was selected along the riv er so th a t the bauxite could be tra n sfe rre d fro m sh ip to storage a t the p la n t w ith a m inim um am ount of handling. I t is sufficiently la rg e to p erm it considerable expansion of the p rese n t m a n u fa c tu rin g facilities. The first u n it w hich was com pleted about two years ago was designed fo r a ca p ac ity o f 500,000 lb. o f anhydrous alum ina p e r day, b u t the efficiency has been so f a r im proved th a t the .p la n t has exceeded this am ount. The ca p ac ity o f th e p la n t a t p rese n t is 1,000,000 lb. p e r day, although by J a n . 1, 1941, this cap acity will have been increased 50 p e r cent.
The p rin c ip a l raw m aterials used in p roducing alum ina are bauxite, lime, and soda ash. All o f these can be obtained from domestic sources,
b u t this p la n t located on tidew ater secures its bauxite from S urinam . I t is b rought across the G ulf of Mex
ico in boats, th rough the Mobile R iver and Three-M ile Creek, w here it is unloaded by the bulk-handling facilities o f the A labam a S tate Docks.
The elam-shell buckets and g a n try cranes unload the bauxite onto a belt conveying system which discharges in an enorm ous storage building. A h o p p er in the floor o f the building discharges the m aterial onto another belt conveyor which carries the baux
ite to the g rin d in g building. All tra m p iron th a t m ay be p rese n t is first removed by p assin g the ore over m agnetic pulleys. I t is then dropped into a p rim a ry ham m er mill. The mill discharge is carried by screw conveyor and bucket elevator to the screen feed bins. These bins dis
charge onto v ib ratin g screens which se p arate the fine m aterial. The over
size ta ilings are conveyed to th eir
special bins which feed two secondary ham m er mills. The discharge from the secondary mills is also conveyed to the screen feed bins. The two- stage g rin d in g is a closed circuit with the screens p roducing bauxite, 100 p e r cent o f which has the desired fineness.
Lum p quicklime is unloaded from fre ig h t ears by a tra c k h o p p er onto a belt conveyor which also term inates in the g rin d in g building. G rinding of the lime is done in an o th er ham m er mill. The two ground raw m a
terials are tra n sfe rre d by screw con
veyors and bucket elevators to the fine m aterial bins located in the a d jo in in g m ixing building.
These m aterials are spouted by g rav ity through butterfly valves into weigh hoppers. In d ividual charges o f bauxite and lime are weighed a t re g u la r intervals. The relative am ounts depend on la b o ra to ry analy
ses o f the bauxite and the liquor w ith
C H EM ICA L & M ETA LLUR GICAL E N G IN E E R IN G • O CTO BER 19Ą0 075
Bauxite is c o n v e y e d from the great sto ra g e b u ild in g on b elt c o n v e y o r s
The alum inum trihydrate is se p a r a te d from the sp en t liquor in thickeners
Trihydrate is h e a te d w h ite hot to d rive of the c h e m ic a lly com bined w a ter
A lum inum trihydrate slu rry is p u m p ed to Dorrco filters w h e r e m ost of the m oisture is rem o v ed . It is d isc h a r g e d from the filters into sc r e w c o n v e y o r s le a d in g into ca lcin in g kiln s
L oad in g a lu m in a into s p e c ia l co v ered h op p er ca rs to b e tak en to other p la n ts to b e re d u c e d to the m etal
070 • O C TO B E R 191,0 • C H EM ICA L & M ETA LLU R G IC A L E N G IN E E R IN G
which it is to be mixed before being processed.
This liquor is a solution o f caustic soda which dissolves alum ina from the bauxite, fo rm in g a solution of sodium alum inate and leaving in sus
pension the im p u rities o f the bauxite.
Im p u ritie s consist p rin cip ally o f iron oxide, titan iu m oxide and silica.
A n electric tim er blows a signal horn a t reg u la r intervals. On this signal the o p e ra to r drops the charge from the weigh h o p p e r into a mixing vessel located below. A stream o f liquor flows into this m ixing vessel.
R o tatin g paddles s tir the contents of the m ixer and a slu rry is discharged from the m ixer and pum ped to the next building w here the digesters are housed.
In the digesters the slu rry is mixed with an ad ditional volume of p re heated liquor, and steam is injected to raise the tem perature. The re su lt
ing thin slu rry flows to a series of d igesting vessels which are equipped with a g ita tin g paddles on central horizontal shafts.
D u rin g passage through the diges
ters, the m ixture is held a t elevated te m p eratu re s f o r a sufficiently long tim e to allow com pletion o f the chem
ical reaction. This consists o f the solution o f the alum ina as sodium alum inate and p rec ip ita tio n o f dis
solved silica in the form o f sodium- alum inum silicate.
SODIUM ALUMINATE LIQUOR On leaving the digesters, the sodium alum inate liquor with a suspension o f im p u rities known as “ red m ud”
passes through tan k s w here the p re s sure is reduced and the liquor is thereby cooled. The steam evolved is used in tu b u la r h eaters to p reh e at the liquor on its w ay to the digesters.
C ondensate fro m all tu b u la r h eaters is recovered f o r use as boiler feed, wash w ater f o r the subsequent p ro d uct, an d m ake-up fo r the m ud wash
ing system .
The suspension o f mud and liquor is pum ped to K elly filter presses, the leaves of which are covered w ith cot
ton duck. The m ud cake deposited on the p ress leaves is given a two- stage washing, a fte r which th e press is opened and the mud removed from th e leaves by a stream o f w ater fro m a ru b b er hose. The m ud falls through h oppers into the m ixing trough. F ro m here the m ud s lu rry is pum ped to settlin g ponds located on B lakely Isla n d across the Mobile R iver from the p la n t site. The overflow from the m ud settlin g ponds is retu rn ed to the p la n t fo r use as wash w ater in the K elly presses. The mud itself is
a waste p ro d u ct a t the present.
L iquor filtrate and w eak liquor r e su ltin g fro m mud w ashing in the presses are conveyed through a trough to a filtrate ta n k located ju s t outside the filter press building. F rom the filtrate ta n k the liquor is pum ped to a series o f elevated coolers.
L iquor fro m the coolers flows by g rav ity into a storage ta n k and is then pum ped to the p re c ip ita tio n de
partm en t. F u rth e r cooling is p ro vided if necessitated by high a t
m ospheric tem peratures, and the liquor then goes to p rec ip ita tin g tanks. These are cylindrical tanks 24 ft. in diam eter and 75 ft. high, in which m eans are provided f o r cir
culation o f the contents. E ach tank fu ll o f liquor is given a seed charge o f previously p recip itated alum inum trih y d ra te and circulated fo r from 30 to 60 hours. D u rin g th is operation ap p ro x im ately one-half of the alum in a content o f the liquor precip itates as alum inum trih y d ra te and is de
posited upon the seed charge p a r ticles.
W hen the circulation is stopped, the contents o f the tan k s are pum ped into thickeners w here the p recip i
ta te d h y d rate is sep arated from the liquor, the final clarification being ac
com plished by D o rr tra y thickeners.
P a r t o f the h y d rate which settles in the thickeners is retu rn ed to process as seed charges fo r subsequent p re c ip ita to r tanks o f liquor. Clarified liquor overflowing the tra y thickeners has soda ash added to m ake u p fo r the soda losses o f the previous cycle.
I t is then passed through preheaters and retu rn ed to the process.
The balance of the h y d rate is re moved from the bottom of the thick
ener and passed th ro u g h a series of w ashing thickeners. These thickeners are large tanks sim ilar to those in which the h y d rate is settled. On leaving each w ashing thickener the h y d rate slu rry is diluted w ith succes
sively w eaker wash w ate r in a coun
te r-c u rre n t' wash. The slu rry of washed h y d rate is then pum ped to a storage ta n k in the calcining d e p a rt
ment.
F ro m the bottom of this storage ta n k h y d rate slu rry flows by g rav ity to D orrco filters which discharge into screw conveyors feeding the ro ta ry kilns. These kilns are 9J ft. by 250 ft. N atu ra l gas is used as the fuel.
COOLING THE ALUMINA The m aterial leaves the kilns a t 1800 deg. F . a f te r having lost the chemically combined w ate r as well as fre e m oisture. The hot alum ina passes through a re fra c to ry spout
into a ro tary cooler in which the tem p eratu re is reduced by a b last of cooling air. A larg e p a r t o f the cooler construction on the feed end is stainless steel. H o t a ir fro m these coolers supplies preh eated a ir fo r the com bustion in the kilns.
On leaving the coolers the alum ina falls into a P eek conveyor which elevates it to the top o f the sh ip p in g bin. I t passes th ro u g h v ib ra tin g screens before d ro p p in g into the bin so as to remove lum ps.
ALUMINA IS SHIPPED
F rom the sh ip p in g bin the alum ina is spouted into the to p o f specially designed steel h o p p e r bottom ears spotted on a tra c k scale. The ears have a cap acity o f ap p ro x im ately 75 tons, and are used to tra n s p o rt the pro d u ct o f this p la n t to the reduction p la n ts o f the p a re n t o r
ganization, the A lum inum C om pany o f A m erica. These la tte r p la n ts are located w here hydro-electric pow er is available. In the loading d e p a rt
m ent are also facilities fo r bagging alum ina fo r shipm ent to o th e r cus
tomers.
The plot on which the p la n t was constructed is sandy low ground which made it necessary to sink a p proxim ately 20,300 piles. A t the presen t time, the level o f the entire a re a is being raised several feet by m eans of sand deposited as dredge spoil from ad jacen t operations.
M achine shops and locker rooni- re sta u ra n t building are brick con
stru ctio n with book-tile roof. The boiler, a ir com pressor, bauxite sto r
age and calcining buildings are steel, covered with corrugated galvanized sheet. The g rinding, m ixing, digester, heater, filtration and p re c ip ita tio n buildings are covered with R obertson protected m etal sheeting.
The last of these is unique, fo r only the o p era tin g floor which is at the to p o f the p re c ip ita tin g tan k s is en
closed. These g re a t 75-ft. ta n k s are in fo u r rows o f eight each. The o p era tin g floor o f each is su pported by steel beams fasten ed to the tank a few feet below the floor; they do n o t extend to the ground. W hile they are grouped an d a p p e a r from the ground to be fasten ed together, each ta n k and its o p e ra tin g floor is sep arate. T his is m ade necessary by th e sw ay o f th e ta n k s when operated.
The w rite r wishes to take this o p p o rtu n ity to express his appreciatio n fo r the courtesies shown him on the occasion o f his visit to the p la n t by M r. D uncan Sm ith, sreneral su p e rin tendent. and M r. R ich ard S. Stokes, assista n t general su p erin ten d en t.
C H EM ICA L & M ETA LLU R G IC A L E N G IN E E R IN G • O C TO B E R 19Ą0 677
How C a rb id e T ests E q u ip m en t To P re v e n t A ccidents
JAMES J. D U G G A N ,
D irector, P ro c e s s S a le ty D e p a r tm e n t. C arb id e & C a rb o n C h e m ic a ls Corp., South C h a r le sto n , W . V a .— — — — — — C h e m . & M e t. I N T E R P R E T A T I O N —
Four-fifths of a ll serious injuries in ch em ical plants are due to m ech anical ca u ses, according to the accid en t prevention studies of the N ational S afety Council. It is h igh ly important, therefore, that organized attention should b e directed toward the elim ination of m ech an ical hazards, e sp ec ia lly those involvin g m achinery and equipm ent. Carbide & Carbon C hem icals Corp. h a s done this effec
tively b y setting up an independent Process S afety Department charged with accident prevention through periodic tests and in sp ec
tion of its m achinery and equipm ent. The work of this departm ent and the ben efits to b e g a in ed b y this typ e of organization are pre
sen ted here b y its director in this abstract of the paper Mr. D uggan p resented before the C hem ical Section of the N ational Safety Council in C hicago on October 8, 1940.—
E ditors.I
N 1934 T H E MANAGEMENT o f the C arbide & C arbon Chemicals C orp o ratio n decided to extend the scope o f its sa fe ty w ork to reduce not only accident severity and frequency ra te s b u t to reduce mechanical failu re s and fire hazards.
I t was believed th a t the corporation could th u s increase overall p la n t efficiency an d help to assure con
tin u ity o f production.
The theory was sound, and a sep
a ra te d ep a rtm en t w as established to o rig in a te and supervise te st an d in spection routines. This d ep a rtm en t w as to be know n as the Process S afety D ep artm en t. I ts direction was to be in dependent o f those p r i
m arily in charge o f p roduction or equipm ent, thus allow ing a fre e ex
pression of opinion concerning the condition o f the equipm ent and the ch aracter o f its m aintenance w ithout being influenced by someone whose p rim a ry in terests centered on g ettin g m aximum production o r keeping m aintenance at lowest cost. Freedom to sta te conditions exactly as found and to criticize constructively w ere considered the prim e requisites fo r a successful te st and inspection organization.
The P rocess S afety D ep artm en t o rig in a ted procedures based on sound engineering p rinciples. The various code requirem ents, fo r exam ple, were considered sta n d ard . E v ery source o f in fo rm atio n w as utilized and w here sta n d a rd p ractice procedures were applicab le to p la n t conditions they w ere included. The services rendered, however, were in no way intended to relieve a d e p a rtm en t su p e rv iso r o f the responsibility fo r the sa fe o p era tio n or m aintenance of his equipm ent. The procedures were intended :
1. To establish a system f o r p e r i
odically te stin g and inspecting all m achinery, equipm ent, and sa fe ty devices.
2. To elim inate a possible cause o f fire, explosion, o r accident through decreasing the likelihood o f any m echanical fa ilu re o f equipm ent.
S. To record all tests, inspections.
and re p a irs by providing suitable re p o rt form s and record system s fo r fu tu re reference.
4. To circulate all re p o rts and in fo rm a tio n compiled to the d e p a rt
m ent heads and all o ther interested persons th a t they m ay know as n e a rly as possible the condition of equipm ent.
5. To establish safe o p era tin g pressu res by stan d ard ized re-test pressu res and procedures, m aking each successive test o r inspection identical, thus giving m eans fo r de
term ining the exact conditions of equipm ent based on p a s t tests.
6. To provide p ro p e r tools, in s tru m ents, and such o ther equipm ent as m ay be found necessary to c a rry on the test and inspection w ork as th o r
oughly and efficiently as possible.
7. To correlate corrosion ra te s and estim ate the life o f all equipm ent and to recom m end the replacem ent o f old o r defective equipm ent before it actually fa ils in service.
8. T hrough the d a ta thus compiled, to be o f assistance in the establish
m ent o f design, construction, and m aintenance standards.
9. To stu d y the design o f new equipm ent and p la n t layout in an effort to elim inate th e rep e titio n of conditions fo u n d to be hazardous.
10. To effect cooperation between production, m aintenance, engineer
ing, and inspection forces th a t each m ight benefit by the experience of the others.
11. To keep th e p la n ts p e rp e tu a lly new th ro u g h the replacem ent of de
fective equipm ent o r m achinery.
The ap p lica tio n w as n o t found as difficult as orig in ally an ticip ated . In v estig atio n revealed the fa c t th a t a larg e p o rtio n o f the necessary w ork was alread y being done. Efficient r e p a ir w ork was effected through the existing m aintenance d epartm ents.
T ests o f some n a tu re were being m ade follow ing each r e p a ir f o r the p u rp o se of determ ining the f a c t th a t s a tisfa c to ry re p a irs h ad been made.
V arious inspection schedules had been established f o r the convenience o f d e p a rtm en t heads. The record o f such w ork, however, w as very incom plete and lacking in detail and thoroughness. To m ake a long sto ry short, much effort was be
ing exerted w ith little benefit. T here
fore, w hen definite procedures were p u t into effect the actual w ork p e r form ed was n o t m aterially increased an d the sm all increase necessary was soon justified. W hen p ro p e rly o r
ganized the to ta l tim e chargeable to process sa fe ty w ork, w hich includes
Ö7S O C TO B E R 19.',0 • C H EM ICA L & M E T A L L U R G IC A L E N G IN E E R IN G
all fire protectio n work, is less than i o f 1 p e r cent o f the total p la n t m an-hours.
Such a system , ap plicable to any ty p e o f in d u stry , m ay be sum m arized as follow s:
1. I t m ust have the ap p ro v a l of the m anagem ent.
2. The system fo r g ath erin g d a ta m ust be routine, specific in req u ire
m ents, and efficient in operation.
3. Com plete cooperation between all p la n t d ep artm en ts is essential to insure com pilation o f all data.
4. À re p o rt m ust be m ade o f each re p a ir as well as each te st and in spection. In fo rm a tio n concerning o p e ra tin g irre g u la rities are valuable also in com piling an accurate serv
ice record. These re p o rts m ust be
come a p a r t o f the record system.
5. A m eans o f identification of all m achinery and equipm ent m ust be provided. F o r exam ple, equipm ent can be g rouped such as motors, com
pressors, boilers, stills, etc., and num bered in ro ta tio n either by de
p a rtm e n t o r in stallation.
6. A ll te st and inspection work m ust be u n d er the supervision of one d e p a rtm e n t to elim inate rep e titio n and to insure com plete coverage and the follow ing o f ap proved p ro cedures.
7. All equipm ent should be p re p a re d f o r test and inspection by th e m aintenance d ep a rtm en t m echan
ics o r o p e ra tin g d ep a rtm en t p e r
sonnel. This arran g e m en t elim inates the necessity f o r d u plication of effort. The actual test, however, m u st be app lied , o r a t least su p e r
vised, by an authorized inspector.
8. In sp ec to rs should coniine th e ir efforts to a detailed analysis o f the p rese n t condition o f equipm ent in o rd e r to establish the ra te o f cor
rosion o r deterio ratio n and th e safe
■operating life of the equipm ent.
W hen this in fo rm atio n is passed on to the m aintenance and design de
p a rtm e n ts it w ill assist them m ate
ria lly in deciding the p ro p e r re p a ir a n d /o r change in design f o r fu tu re installations.
9. The re p o rts subm itted should fo rm a “service rec o rd ” o f each in dividual piece o f equipm ent and be k e p t in a convenient place accessible to all interested persons. I f neces
sary, du p licate system s m ay easily be m aintained.
10. W hen periodic te st and inspec
tion reveals equipm ent to be u n sa tisfa c to ry fo r the o p era tin g con
d itio n s to which it is subjected, it should be rem oved to a less severe service o r condemned and com pletely rem oved fro m service. This decision
is reached by ap p ly in g sound engi
neering principles, and by consulta
tion w ith the p la n t engineering and m aintenance engineering d e p a rt
ments.
All info rm atio n should be circu
lated to or made available to all u n its o f a p la n t or p la n ts w ithin a corporation th a t they m ay ju d g e sim ilar equipm ent in sim ilar service u nder th eir supervision. W ith this info rm atio n available to m aintenance and design engineering groups, fu tu re p la n t extensions o r replace
m ents can be m ade to the best ad
vantage elim inating the rep e titio n of hazardous conditions and assuring more efficient p la n t operation. I n efficiencies in the design and fa b ri
cation of m achinery and equipm ent can m any times be rectified if de
tailed field experience as reflected in the service record is called to the atten tio n o f the supplier.
The results to be obtained from a p ro g ra m o f periodic test and inspec
tion are far-reaching. The experi
ence o f the Carbide and Carbon Chemicals C orporation has proved th a t fac t beyond a doubt. The equip
m ent is b etter m aintained and the personnel has been b etter educated as to m echanical lim itations. A b rief
sum m ary o f this p ro g ra m as outlined indicates t h a t :
1. P la n t m achinery and equipm ent have been operated m ore efficiently.
2. The p la n ts have been provided w ith an additional m eans o f fire p re vention.
3. A continuing service record has been provided f o r all equipm ent.
4. D ata have been com piled fo r fu tu re design and m aintenance.
5. A m eans of education o f the p la n t personnel has been effected through the circulation o f detailed re p o rts giving to them info rm atio n heretofore not available as to the condition and lim itations o f equip
m ent u nder th eir supervision and control.
6. Overall p la n t efficiency has been increased.
7. A ccidents have been prevented.
In a final analysis based on p e r
sonal experience, I have fo u n d no excuse fo r accidents, th a t they can be elim inated, th a t prevention m easures are economically sound and th a t there is enough available inform ation on the subjects involved which, if a p plied to individual o r specific p ro b lems, will enable any organization successfully to ca rry o u t an accident prevention program .
S a fe ty is the N o. 1 consideration, a t C arbide’s fa m o u s ch em ica l p la n t
W a te r S u p p ly E q u ip m en t in th e
P ro c e ss In d u s trie s
G RAHAM L. M ONTGOMERY
A s s o c ia te E ditor. F ood In d u s trie s . N e w Y o rk , N. Y.
C h e m . & M e t. I N T E R P R E T A T I O N
This Sterling d e e p w e ll turbine pum p is o n e of 18 pu m p in g from a depth of 700 ft. for the W e s tv a c o C hlorine Products Co., South C harleston, W . V a .
P
u m p i n g o f w ater supplies fo r in d u stria l p la n ts lias undergone considerable change d u rin g the p a s t 25 years. A t the beginning o f th a t period, w ate r p u m p in g equipm ent was g re a tly different from th a t now usually seen in p la n ts o f th e p ro cess industries. W ells were usually pum ped by some fo rm o f re c ip ro catin g p u m p o r by a ir-lifts and, while ce n trifu g al p u m p s were beg in n in g to a p p e a r in this service in considerable num bers, n eith er in de
sign no r ap p lica tio n could to d a y ’s economies be realized.
’ tf
T ' M odern -water su p p ly m ethods are based in large p a r t u p o n experience o btained in the su p p ly o f w ate r fo r m unicipal an d a g ric u ltu ra l pu rp o ses in the m ore arid regions of the -;i'.TJnited S tates, like C alifo rn ia and► .y%_
the. Southw est. There, w here most su rface stream s d isa p p e a r d u ring the y ea rly d ry season and w ith few
‘n a tu ra l lakes to draw on, the m eager su p p lies provided by im pounding the scanty ra in fa ll soon proved in sufficient. Recourse was first had to shallow wells, which served fo r a time. Soon, however, the w ate r level in these wells receded and it became necessary to ta p the large supplies of gro u n d w ater lying a t deeper levels.
As th e depth o f wells increased, the designers o f w ell-pum ping equip
m ent were forced to develop pum ps
Suitable an d econom ical sou rces for w ater is a problem that h as recently com e to the fore with m an y p rocess industries. Increasing w ater costs ow in g to shrinking su pplies, and the n eed for estab lish ing p lan ts in n ew location s for norm al exp an sion or d efen se pur
p o ses, are am ong the c a u se s for this interest. In the first article of this series, in Septem ber, the author d iscu ssed w ater requirem ents for process industries, and a lso the typ es of w ater su pp lies in vari
ous parts of the United States. This secon d paper d ea ls with modern m ethods of w ater su pp ly pum ping. The third and concluding article, to b e presented in our D ecem ber issu e, w ill h a v e a s its subject the solution of typical pum ping problem s in h and ling w ater and other liquids in p rocessing, a s distinguished from primary water su p p ly pum ping, a s in the present article.
— E ditors.th a t would o p erate economically and w ithout undue m aintenance req u ire
m ents a t these deeper levels. The suction lif t a t w hich a p u m p can o p erate effectively is stric tly lim ited, so th a t it became necessary to place the p u m p down in the well. As a result, the p u m p was com pelled to raise the w ate r to a g re a te r discharge height, in which the distance from the p u m p in the well- to thife surface of the g ro u n d was added to the height (head) to which the w ater had to be raised above ground.
This evolution in design resulted in the developm ent o f the vertical deep well tu rb in e pu m p , which be
cause o f its relatively high efficiency and its trouble fre e operatio n , has m ore o r less pre-em pted the field of well p um ping. Modified designs of vertical pum ps, suitable f o r p u m p in g w a te r a t low er heads, w ere de
veloped because o f the success o f the
Pom ono d e e p w e ll turbine pum p o p era t
in g on a h e a d of 480 ft. in a ch em ica l plan t at Fort W orth, T exas
(ISO O C TO B E R 191,0 • CHEM ICA L & M ETA LLU R G IC A L E N G IN E E R IN G
deep well pum p. More recently, vertical p u m p s have begun to be ap p lied to m any p u m p in g o p e ra tions o ther th a n w ater supply, be
cause o f th e ir characteristics o f good perform ance, low m aintenance, sm all floor space requirem ent and self
prim in g operation.
V arious p u m p m a n u fa ctu re rs give these vertical p u m p s a v ariety of names, b u t th e nom enclature of the P om ona P u m p Co. will serve fo r illustration. The three im p o rta n t classes, according to this com pany, are the deep well tu rb in e pum p, the mixed-flow pu m p , and the p ro p eller pum p. The deep well tu rb in e pum p is essentially a ce n trifu g al p u m p of the “ tu rb in e” ty p e in which the w ater enters a t the in n e r p erip h e ry o f th e im peller and, on leaving the ou te r tip s of the im peller blades, passes th ro u g h vanes which convert into p ressu re the velocity im parted to the w ate r by the im peller. Since wells are lim ited in diam eter, the
diam eter of the pum p and hence the p ressure head created by one im peller and set of vanes is also limited.
T herefore, deep well pum ps are usually m ade up o f a series of tu rb in e pum ps, o r stages, one above the other, so arran g e d th a t the dis
charge of the first stage enters the suction o f the second stage, and so on.
A three-stage deep well turbine pum p, a rran g e d fo r direct-connectcd electric drive w ith surface discharge is shown in F ig. 1. As indicated by this sketch, the deep well pum p is norm ally set in a well lined w ith a metal casing th a t is pierced in its low er p o rtio n to adm it w ate r from the w ater-bearing s tr a ta of the ground. Below the first stage of the pum p is a bearing to hold the stub end o f th e pum p s h a ft and a stra in e r to keep coarse g r it out o f the pum p.
Above the la st stage of the pum p a
“ colum n” o r tube extends u p to the top o f the well, where it is rig id ly
secured. This column serves as a delivery p ip e to conduct the w ater th a t is being pum ped to the top of the well. I t also serves as a means o f su p p o rt fo r the s h a ft bearings and it carries the w eight o f the pum p.
D ischarge a t the to p o f the well can be piped u p to su it the installation.
The pum p in g u n it is subm erged in the well to a p o in t below the w ate r level.
Deep well tu rb in e pum ps also can be driven from engines through g e a r
ing, o r can be belt-driven fro m en
gine o r m otor.
A recent design o f m otor-driven deep well pum p, shown in F ig . 2, is equipped w ith a subm ersible m o
tor, instead o f being driven from above as is the p u m p in F ig . 1. This design avoids the use o f th e long sh a ft extending down from the top of the well. Consequently there are few er bearings, less fric tio n loss and, where the well is not stra ig h t, there is avoidance of excessive w ear on
Discharge elbow
Column pipe
Uotor_
cable
■Strainer
M e r c u r y - s e a l
Motor
■Oil¡eve!
in d ic a to r
— S u rfa ce . 1 p la te
. Well 'casing F ig. 1, Left— P om ona m ulti-stage d eep
w e ll turbine pum p w ith direct-connected motor, in sta lle d in a w e ll c a s in g for d e liv e r y to an o v e r h e a d w a te r su p p ly tank
K e y to r e fe re n c e l e t t e r s : a , e n tr a n c e s w itc h : b, m o to r s t a r t e r ; c, c u r r e n t c o n t r o l r e la y ; rf, p r e s s u r e c o n tr o l s w itc h ; e, m o t o r ; / , a i r v e n t, v a l v e ; g, p r e lu b r ic a tio n w a t e r c o n tro l v a lv e ; h, p r e lu b ric a tio n w a t e r p ip e ; i. c h e c k v a lv e ; j , g a te v a lv e ; k , w a t e r lu b r ic a te d r u b b e r b e a r i n g ; I, t u r b in e p u m p b o w l ; tn, s e m i-o p e n im p e lle r ; n, s u c tio n s t r a i n e r
F ig. 2. Right— D eep w e ll turbine pump w ith su b m erg ed motor, a s built b y Byron Jackson Co. A n oil s e a l p rev en ts w a ter from com ing in contact w ith the motor
CHEMICAL. & M ETA LLUR GICAL E N G IN E E R IN G • O CTO BER 191,0 681
F ig . 3— P rop eller ty p e P om ona pum p s h o w n in sta lle d on a w o o d e n support o v er a river, for liitin g la r g e am ounts of w a te r to a reservoir or tank situ a te d on the b an k
F ig. 4— M ixed-flow P om on a pum p a rra n g ed to lift w a ter from a con crete sum p or ca ic h b a sin . B y m u lti-sta g in g this ty p e of p um p, m uch h ig h er h e a d s ca n b e h a n d le d ro ta tin g p a rts . This design also
elim inates need f o r a stuffing box aro u n d the s h a ft a t the top of column, thereby reducing fric tio n and avoiding an y leaks. B earing loads w ith this pum p are said to be ab o u t h a lf those encountered w ith the su rfa ce drive type o f deep well pum p. A n o th er advantage claimed f o r the design is th a t th e m otor al
ways o perates a t the same te m p era
ture, regardless o f the a ir tem p era
tu re a t th e surface.
LOW-LIFT PUMPS
The p ro p eller pum p shown in F ig.
3, is designed f o r delivering large ca p ac ity a t low heads. I t is of the axial flow type. T hat is, th e w ater flows th rough the im peller in a direc
tion p ara llel to the axis o f the pum p sh a ft, instead o f flowing fro m the center o f the im peller to its outside p erip h ery , as in a tu rb in e o r volute c e n trifu g al pu m p . This im peller re sembles a sh ip ’s screw in app earan ce.
I t p ro p els the w ate r u p w ard through the p u m p colum n and develops only a sm all am ount o f ce n trifu g al action.
P ro p e lle r p u m p s can lif t larg e q u an titie s o f w ate r com pared to other
pum ps, b u t only a t low heads. U nder such conditions, they o p era te a t high efficiency, b u t as the head is in creased, the horsepow er req u ired in creases and the ca p ac ity falls off.
E x ce p t f o r the p u m p im peller and casing design, p ro p eller pum ps are sim ilar to deep w ell pum ps. T heir m ain use in process in d u stry w ater su p p ly is f o r ra isin g w ater through low lifts from rivers o r lakes, w here the w a te r level is likely to v a ry b u t w here a f a ir ly co n stan t su p p ly is necessary.
Mixed-flow pum ps, one o f which is shown in F ig . 4, are in the m ain sim ilar to p ro p e l’.er pum ps, except th a t the im peller is modified, so th a t a p u m p o f this ty p e will produce a p ressu re head fro m two to three tim es th a t o f a p ro p e lle r p u m p of corresponding size. These p u m p s are ap p lied w here the w ork to be done is interm ediate between the field o f the deep well tu rb in e p u m p and the p ro p e lle r pum p. Mixed-flow pum ps can be m ulti-staged, as are deep well pum ps, in o rd er to p u m p w ater ag ain st h ig h e r heads.
F ield s of ap p lica tio n o f these three general types o f w ater su p p ly
p um ps overlap. This is clearly shown by F ig . 5, a p u m p allocation c h a rt developed by P om ona P u m p Co. in which the shaded p o rtio n s show w here the three types o f p u m p s over
lap . The lim its shown on the ch art fo r each ty p e o f p u m p are based upon P om ona design, b u t other m a n u fa c tu re rs offer the same types f o r ap p ro x im ate ly the same head- ca p ac ity conditions. A n estim ate of the req u ired m otor r a tin g can be obtained b y dividing the w ate r horse
p ow er by the pum p efficiency.
VOLUTE PUMPS
I n ad d itio n to the three classes of v ertical p u m p s alre ad y described—
p u m p s th a t were developed specifi
cally f o r han d lin g w a te r but are now fre q u en tly used f o r o ther liquids
— the volute c e n trifu g al pum p is also used, in v ertical m ountings, fo r h an d lin g w ate r and o th e r liquids.
This is the same ty p e of p u m p so com monly used in h o rizontal m ount
ings f o r general p u m p in g service.
I n the v ertical type, it m ay be o f the close-coupled design in which the p u m p is m ounted directly below the m otor, o r the so-called “sum p” p u m p
GS2 . O C TO B E R 1940 • C H EM IC A L & M E T A L L U R G IC A L E N G IN E E R IN G
design show n in T ig. 6 may be used, in which the p u m p is suspended from the m otor base on a colum n o f su it
able length. I n w ate r su p p ly work, these vertical volute p u m p s are a d a p te d to in stallatio n s w here a suction lif t is involved and are su it
able f o r suction lifts u p to a m axi
mum o f 20 ft.
C a p ac ity f o r a deep well tu rb in e p u m p will ran g e u p to about 10,000 gal. p e r xnin., while head will ran g e fro m 50 to 800 ft. W ith the low- lift, p ro p eller-ty p e o f vertical pum p, capacities ran g e u p to 100,000 gal.
p e r m in. fo r a single-stage pum p, w ith heads u p to abo u t 25 f t. Mixed- flow v ertical p u m p s have capacity and head ran g es between those of th e deep well tu rb in e and pro p eller pum ps. The ca p ac ity and head range o f volute c e n trifu g al pum ps will v a ry w ith the design and size. One
■well-known line has capacities from 20 to 450 gal. p e r min., w ith a head ran g e fro m 60 to 250 ft.
VERTICAL PUMP APPLICATIONS As indicated by the inform ation given on the various classes o f v erti
cal pum ps, equipm ent is available to m eet w ith low o p era tin g and m aintenance costs the w ate r su p p ly needs o f an y process in d u stry p lant.
This equipm ent has undergone m any
F ig. 6— V ertical "sum p" ty p e pum p u sin g a S terling v o lu te cen triiu g a l s u s p e n d e d b y a colum n from the p la te su p
p orting the motor
y ears o f development, w ith resulting im provem ent to the p o in t w here its reliab ility in service m ay be depended upon by th e process in d u stry p la n t needing definite quantities o f w ater w ithout in te rru p tio n (see Cliem. £ M et., S ept. 1940, page 622).
The o rd in ary applicatio n o f this p u m p in g equipm ent presents no difficulties n o t already solved in su p ply in g w ater fo r m unicipal purposes, or in irrig atio n o r o ther fields where vertical pum ps are now the accepted means o f w ate r handling. W here deep wells are the source o f supply, it is necessary to go to g re a te r ex
pense than when the su p p ly is from shallow wells, because both the con
struction of the wells, and the deep well tu rb in e pum ps, cost more than is the case w ith shallow' wells and pu m p s of low er head range. H ow ever, these deep wells are a necessity in some regions because no other adequate source o f w ater is available.
A nother reason fo r using deep wells as a source o f w ate r is the necessity fo r a su p p ly a t a low tem perature. W a te r from stream s, lakes o r shallow wells w ill v a ry in tem p eratu re as the seasons change and m ay be as high in tem p eratu re as 90 deg. F . d u rin g the hot m onths.
W hen cool w ater f o r use in con
densers, cooling coils and like p ro cessing equipm ent is needed in large q u an tity , it m ay prove to be a saving to invest in a deep well and the necessary p u m p in g equipm ent to su p p ly n a tu ra lly eool w ate r ra th e r than to depend on artifically cooled w ater.
H ow ever, in choosing a w ater supply, it is advisable to keep in
m ind th a t ground w aters are likely to be h a rd e r and to have a g rea ter m ineral content than su rface w aters.
This is p a rtic u la rly tru e in m ost of the states situ ate d “ between the m ountains” and “ aw ay from the coasts,” w here considerations o f n a tional defense are causing m any of the new process in d u stry p la n ts to be erected. This f a c t was brought o ut in the first article o f this series (see Cheni. & M et., S ept. 1940, pp.
622 to 625, and p a rtic u la rly the table on p. 624).
H a rd w aters and those of high m ineral content m ust be trea ted be
fo re they are suitable f o r use in m any process industries. E ven when such w ate r does n o t en ter into the process in any way, b u t is used only in cooling equipm ent, boilers and the like, its use m ay cause serious p ro b lems th rough th e scaling u p o f equip
m ent or sto p p a g e o f flow in p ip e lines. F o r exam ple, in a coal p ro d ucts p la n t in In d ia n a a new well was sunk to augm ent an insufficient w ate r su p p ly and to provide cool w ater to use in new cooling coils th a t were being' installed in the benzol p lan t. W ith in two m onths, the coils had been so reduced in efficiency th rough scale form ation th a t a differ
en t source o f w ater had to be sought.
A nd, incidentally, the cost o f rem ov
ing about 3 /1 6 in. o f flint-like scale fro m hundreds o f fee t of p ip e in the coils drove home the lesson th a t it p ay s the chemical engineer to give tho u g h tfu l atten tio n to the q u ality o f his w ater supply.
V ertical p u m p s have n o t been so widely applied by in d u stria l p la n ts fo r pum p in g w'atcr from shallow
F ig. 5— D iagram d e v e lo p e d b y P om ona Pump Co. to sh o w fie ld s of a p p lica tio n of d e e p w e ll turbine, m ixed -flow a n d p ro p eller ty p e p u m p s a s u se d in w a ter
su p p ly . S h a d ed portions s h o w w h e r e the three ty p e s o v e r la p
C H EM IC A L & M ETA LLU R G IC A L E N G IN E E R IN G • O CTO BER 1<J1,0 • 083
wells, stream s and lakes as have horizontal p u m p s and o ther types o f p u m p in g equipm ent. H owever, such ap p licatio n s are now being m ade m ore freq u en tly , n o t only be
cause o f the suitable characteristics o f the pum ps, b u t also because o f the relatively low cost o f in stallation.
V ertical p u m p s can be suspended from a small and inexpensive stru c ture in com parison to the fou n d atio n needed fo r h o rizontal p u m p in g equ ip m ent o f equal cap acity an d head.
SOME NOTABLE INSTALLATIONS N ear F resn o , Calif., a p u m p in g in stallatio n supplies over 2,000 gal.
p e r min. o f cooling w ate r fro m the S an Jo a q u in R iver. Three vertical pum ps are installed, each of 750 gal.
p e r min. ca p ac ity a t 362 ft. head.
These p u m p s are seven-stage deep well tu rb in e pum ps, o p era tin g at 1,750 r.p.m . an d each driven by a direct-connected 100-hp. m otor. The pum ps are installed over the riv er on a p la tfo rm th a t is 50 f t. above norm al w ate r level. This p la tfo rm and the w alkw ay connecting it to the riv e r b an k are of trestle con
struction. W hile th e whole stru ctu re is lig h t in w eight and inexpensive, it is am ple to su p p o rt the pum ps on a level w ith the b a n k and above any possible high w ater. Such a construction is much less costly th a n the elaborate stru c tu re and p rec au tions ag a in st flood th a t would be necessary if p u m p s o f horizontal ty p e had been used, ra th e r than the vertical p u m p s th a t w ere selected.
I n S o uthern C alifornia, n e a r Los Angeles, a su p p ly o f w ate r w as sought fro m the norm ally d ry bed
of the S an Luis R ey R iver. I t was known th a t an am ple su p p ly of w ate r existed below the riv er bed, so th a t a well in th e riv er bed would ta p a co n stan t source. H ow ever, a t ce rtain tim es the riv e r bed is sub
jected to flooding and a n y well in it h ad to be p rotected fro m contam ina
tion b y flood w aters and from scour
in g by flood, while the p u m p in g equipm ent itself and its electric con
nections needed to he p ro o f ag a in st flood dam age.
In solving this problem , an 18-in.
diam eter well easing pro tected by a steel and concrete covering w as ex
tended to a d ep th o f 42 f t . —below any possible scouring action o f floods.
In th is casing is a 14-in., tw o-stage deep well tu rbine p u m p o f 1,000 gal. p er min. capacity a t 60 ft. head.
M otor drive f o r the pum p is by a subm erged m otor below the pum p u n it, sup p lied w ith pow er fro m a cable b uried 12 f t. deep beneath the riv e r bed.
Above the riv er bed level, the well is capped w ith a steel housing, 26 in.
in diam eter and cylindrical in shape.
This offers a m inim um o f resistance to flow of the stream d u rin g floods and to im pact o f flood debris. The discharge line fro m the p u m p is carried out o f this steel stru c tu re and extends down to a p o in t 12 ft.
below the riv e r bed w here it runs through the same trench w ith the pow er cable, secure fro m damage.
W hile this w ater su p p ly could have been secured in some other m anner, the advantage o f the m ethod selected is evident fro m the sim plicity o f the w ork th a t had to be u n d ertak en in the bed o f the riv e r
in order to secure p rotection during periods o f flood.
A n u nusual w ater su p p ly , involv
in g the use o f two p u m p s in one well, has been installed in Riverside, C alif. The p u rp o se o f this in sta lla tion was to provide a su p p ly a t three different ra te s o f delivery, w ith a m inim um o f expense fo r both wells and pum p-house.
UNUSUAL PROBLEMS
The well is 468 f t. in depth. F o r the first 50 f t. its diam eter is 36 in., reduced to 20 in. f o r the rem ainder o f the depth. Two deep-well tu rb in e pum ps, one o f 1,200 and th e other o f 2,400 gal. p e r min. ca p ac ity are installed side by side in the well, each w ith a to ta l head o f 230 ft.
Thus the in stallatio n has capacities o f 1,200, 2,400, o r 3,600 gal. p e r min., all a t m axim um efficiency. The r e inforced concrete pum p house neces
s a ry to accom modate this installation is only abo u t 21x13 ft. in outside dimensions.
The th ree exam ples ju s t given well illu strate how rea d ily sta n d a rd de
signs o f vertical pum ps can be ad a p te d to unusual or difficult p ro b lems o f w ater supply. In th e same way, v ertical p u m p in g equipm ent, sometim es o f sta n d a rd and sometimes o f modified design, is a d a p ta b le over a wide ra n g e o f p u m p in g problem s occurring in the han d lin g o f w ater as well as o th e r liquids in th e course of processing operations. I n the con
cluding article o f this series, a num ber o f these processing p u m p in g in stallatio n s will be discussed, in o rder to illu strate how certain p u m p in g problem s have been solved.
W h ere ground w a te r s a r e too hard, freq u en tly g r e a t
est e c o n o m y ca n b e a c h ie v e d through the u s e of a w a te r co o lin g to w er. This m odern a erator ty p e a t
m osp h eric c o o lin g tow er, w h ich w a s rece n tly erected
b y The Fluor Corp., Ltd., for the A m erican P otash &
C hem ical Co., at Trona, C alif., h a s a c o o le d w a te r c a p a c ity of 25,000 g a l. p er m in. It is b e lie v e d to b e
the la r g e s t su c h tow er in the w orld
6S4 O C TO BER 191,0 • CHEM ICA L & M ETA LLU R G IC A L E N G IN E E R IN G
