airlift pump article 1987[1]

5/21/2018 Airlift Pump Article 1987[1]

1/14

Aquacultural Engineering 6 (1987) 97-110

D esig n of Airlift P um p s for W ater Circulation and

Aerat ion in Aqu acul ture

N i c k C . P a r k e r a n d M a r y A n n a S u tt l e

US

Fish and Wildlife Service, Southeastern Fish Cultural Laboratory, Marion,

Alabama 36756, USA

A B S T R A C T

Water f lo w rates were me asure d in a ir lif t pu m ps 3 75-30 cm in d iameter

to deve lop per form anc e da ta tha t m ight be use fu l to aquaculturis ts . F lows

were de te rmin ed whe n subm ergenc e o f a ir lif ts was 100% an d w hen the

cen t er -l ine o f the d i scharge w as be tw een 12 5 cm above and 5 cm be l ow

the water surface. A ir was injected at 15-c m intervals fro m 15 cm to

120 cm be lo w the d i scharge o f the a ir lift an d a i r f lo w was var ied f ro m 28

to 141 6 l iters rain - 1. A n increase in the ver t ical li ft redu ced f lo w rates

great ly in larg e-diam eter pipes , bu t on ly s light ly af fected f lo w rates in

sma l l -d iame ter p ipes . Water f lo w increased linearly as a i r f lo w increased

logarithmically.

I N T R O D U C T I O N

W a t e r c i r c u l a t i o n a n d a e r a t i o n i n a q u a c u l t u r e p o n d s h a v e i n c r e a s e d

p r i m a r y p r o d u c t i v i t y , r e d u c e d s t r a t i f i c a t i o n , i n c r e a s e d n u t r i e n t s o l u b i l i -

z a t io n , r e d u c e d o r g a n i c a c c u m u l a t i o n o n th e b o t t o m , a n d i n c r e a s e d f is h

p r o d u c t i o n . P o n d a e r a t i o n t e c h n i q u e s h a v e b e e n in v e s t ig a t e d to in c r e a s e

t h e g r o w t h , s u rv i v al , a n d p r o d u c t i o n o f b o t h f is h ( It o

et al . ,

1 9 7 4 ; S a r i g

a n d M a r e k , 1 9 7 4 ; P a r k e r, 1 9 7 9 , 1 9 8 3 ) a n d c r u s t a c e a n s ( M o r r is s y , 1 9 7 9 ;

A p u d a n d C a m a c h o , 1 9 8 0 ). A i rl if t p u m p s o f v a r io u s s iz es a n d c o n -

f i g u r a ti o n s h a v e b e e n u s e d t o c i rc u l a te a n d a e r a t e p o n d w a t e r , b u t d u e

t o

f lu c t u a t in g w a t e r l ev e l i n p o n d s , n o t a l l s y s t e m s h a v e w o r k e d r e li a b ly a n d

e f f i c i e n t l y . T h e d e s i g n a n d f l o w p r e d i c t i o n s f o r a i r l i f t p u m p s h a v e

t y p i c a l l y b e e n b a s e d o n d a t a d e r i v e d f r o m s m a l l s y s t e m s s u i t a b l e

f o r

a q u a r i a a n d t a n k s , o r f r o m p e r f o r m a n c e c h a r t s s h o w i n g t h e v e r t i c a l l i f t

c a p a c i t y o f a ir li ft s t h a t a r e 4 0 - 9 0 % s u b m e r g e d ( S p o t te , 1 9 7 0 ; C a s t r o

e t a l . ,

1 9 7 5 ; M u r r a y

e t a l . ,

1 9 8 1 ) .

97


2/14

9 8 N. C Parker M. A. Suttle

I v e n s ( 1 9 1 4 ) r e p o r t e d t h a t a ir li ft p u m p s w e r e t e st e d i n a l a b o r a t o r y i n

G e r m a n y a s e a r ly a s 1 7 9 7 a n d t h a t t h e i r f ir s t p ra c t ic a l a p p l ic a t i o n i n th e

U n i t e d S t a te s w a s i n p u m p i n g o i l i n P e n n s y l v a n i a i n 1 8 4 6 . I n t h e a q u a t ic

s c ie n c e s , a i r li f t p u m p s h a v e b e e n u s e d t o c o l l e c t s a m p l e s o f s e a w a t e r

( T o k a r

e t a l . ,

1 9 8 1 ) ; t o p r o v i d e a e r a t i o n , a g i t a t i o n , a n d p u m p i n g i n

s e w a g e t r e a t m e n t p l a n t s ( A n d e e n , 1 9 7 4 ) ; a n d t o p r o v i d e a e r a t i o n ,

d e s t ra t if ic a t io n , a n d p u m p i n g f o r a q u a c u l t u r e ( R a p p a p o r t et a l . , 1 9 7 6 ;

W h e a t o n , 1 9 7 7 ; P a r k e r

et a l . ,

1 9 8 4 ) .

S e v e r a l i n v e s t i g a t o r s h a v e r e p o r t e d t h e f l o w r a t e s o f s m a l l - d i a m e t e r

a i rl if t p u m p s u s e d t o l if t w a t e r v e r ti c a ll y . S p o t t e ( 1 9 7 0 ) p r e s e n t e d d a t a o n

t h e v e r t ic a l l if t c a p a c i t y o f a ir li f t p u m p s 2 . 5 - 1 5 c m i n d i a m e t e r a n d

4 0 - 7 0 % s u b m e r g e d . S p o t t e (1 9 7 9 ) r e v i s e d t h e w a t e r f lo w r at es f r o m h is

e a r l i e r e d i t i o n a n d a l s o i n c l u d e d f l o w r a t e s o f a i r . C a s t r o

et a l .

( 1 9 7 5 )

r e p o r t e d o n t h e p u m p i n g r a t e o f a i r li ft p u m p s 1 . 2 7 - 7 . 6 2 c m i n d i a m e t e r ,

3 0 c m to 3 .7 m lo n g , a n d 4 0 - 7 0 % s u b m e rg e d . T o d o r o k i et a l . ( 1 9 7 3 )

d e v e l o p e d e q u a t i o n s f o r p r e d i c t in g th e f lo w i n a ir li ft p u m p s 2 . 5 - 1 0 c m

i n d i am e te r , 4 - 4 2 m l o n g, a n d 4 0 - 8 0 % s u b m e r g e d .

A i r l if t p u m p s u s e d t o c i r c u l a te w a t e r in p o n d s o p e r a t e a l m o s t to t a ll y

s u b m e r g e d a n d n e e d t o m o v e w a t e r o n ly f r o m th e b o t to m o f t h e p o n d to

t h e s u r f a c e . T h e t h e o r y o f o p e r a t i o n a n d e q u a t i o n s d e s c r i b i n g p e r -

f o r m a n c e f o r a i rl i f t p u m p s o p e r a t e d i n t h is m o d e h a v e p r e v io u s l y b e e n

r e p o r t e d b y N i c k li n ( 19 6 3 ). M u r r a y

et a l .

( 1 9 8 1 ) d e f i n e d t h e n o m e n c l a -

t u r e u s e d t o d e s c r ib e a i rl if t p u m p s , d i sc u s s e d t h e o r y o f o p e r a t io n , a n d

p r e s e n t e d p e r f o r m a n c e d a t a o n p u m p s o f 1 - 7 8 -3 . 6 5 c m i n d i a m e t e r

o p e r a t e d a t 5 0 - 8 0 % s u b m e r g e n c e . P e r f o rm a n c e d a ta o n a ir li f t p u m p s

o p e r a t e d a t 9 0 - 1 0 0 % s u b m e r g e n c e h a v e n o t b e e n p r e s e n te d p r ev io u s ly .

T h e f ir s t o b j e c t iv e o f o u r s tu d y w a s t o d e t e r m i n e t h e i n f lu e n c e o f th r e e

v a r ia b l e s - - p i p e d i a m e t e r , d e p t h o f a i r in j e c t io n ( c o m m o n l y r e f e rr e d t o

a s s u b m e r g e n c e r a ti o ), a n d v o l u m e o f a i r in j e c te d - - o n t h e w a t e r f lo w

r a te o f a ir l i ft p u m p s s u i t a b le f o r u s e i n a q u a c u l tu r e p o n d s . O u r f u r t h e r

o b j e c t i v e w a s t o r e p o r t t h e s e d a t a i n a f o r m a t r e f le c t in g a c t u a l a n d

e x p e c t e d p e r f o r m a n c e u n d e r f ie ld c o n d i ti o n s .

M A T E R I A L S A N D M E T H O D S

W a t er fl o w ra t es w e r e d e t e r m i n e d i n ei g h t a i rl if t p u m p s 3 . 7 5 - 3 0 c m i n

d i a m e t e r i n t o w h i c h v a r i o u s v o l u m e s o f a i r w e r e i n j e c t e d a t d i f f e r e n t

d e p t h s . R e p l i c a t e m e a s u r e m e n t s w e r e m a d e u n d e r e a c h t e s t c o n d i t i o n

u n t i l t h r e e s i m i l a r r e a d in g s w e r e o b t a i n e d . T h e m e a n o f t h e s e t h r e e

r e a d i n g s w a s a c c e p t e d a s t h e f lo w r a t e u n d e r t h e te s t c o n d i t i o n s .


3/14

A i r l i f t p u m p s o r w a t er c i r c u l a ti o n a n d a er a t i on

9 9

Air li ft pump opera t ion

A i r l i f t p u m p s w i t h n o m i n a l d i a m e t e r s o f 3 . 7 5 , 5 . 0 , 7 . 5 , 1 0 , 1 5 , 2 0 , 2 5

and 3 0 c m (ac tua l in ternal d iameters w ere 4 .4 , 5 -2 , 7 . 6 , 10 2 , 15-4 , 21 .0 ,

2 6 . 4 a n d 3 1 - 3 c m ) w e r e c o n s t r u c t e d f r o m p o l y v in y l c h lo r i d e ( P VC ) p ip e .

E a c h p u m p c o n s i s t e d o f a v e rt ic a l s e c t i o n o f p i p e f it te d w i t h a 9 0 * e l b o w

at the upper end (F ig . 1 ) . A ir was in jec ted in to the s ide o f the ver t i ca l

p i p e t h r o u g h a s er i es o f 1 . 2 5 - c m h o l e s p l a c e d a t 1 5 - c m i n te r v al s f r o m 1 5

t o 1 2 0 c m b e l o w t h e h o r iz o n t a l a rm o f t h e P V C e lb o w . T h e r e w a s o n ly

o n e h o l e p e r 1 5 - c m i nt er v al i n 3 - 7 5 - 1 5 c m d ia m e t e r p ip e s, t w o h o l e s p e r

in terva l in 20 cm d iameter p ipes and three ho les per in terva l in 25 and

3 0 c m d i a m e t e r p i p e s . Ea c h 1 . 2 5 - c m h o l e wa s t a p p e d t o r e c e i v e a 1 . 2 5 -

cm hos e adapter . T he bot to m of the ver ti ca l p ipe ( the a ir lift pum p in take)

wa s 1 3 0 c m b e l o w t h e h o r iz o n t a l a rm o f t h e e l b o w ( th e air lift p u m p d i s -

charge) .

Th e b o t t o m o f t h e d i s c h a r g e e l b o w wa s p l a c e d 1 . 2 5 c m a b o v e t h e

w ater l eve l in a f lume, l ocated jus t abo ve the water surface (F ig . 1 ) and

A * p u m p . . - - .b ~

P t e l | u r e g a u g e

T A i r * w a l t e r

s e p a r a t i o n F l u m e

1 , 2 5 m A i r l i n e

.......

e

e

1 3 0 c m

e

e ~

e

e

1 . 2 5 c m

F i g . 1 . T e s t a p p a r a t u s f o r m e a s u r i n g w a t e r f l o w i n a i r l i f t p u m p s . E a c h p u m p c o n s i s t e d

o f

a 9 0

e l b o w a n d a ve r t ic a l ris e r. T h e d i s c h a r g e w a s 1 . 2 5 c m a b o v e t h e s u r f a c e o f t h e

w a t e r a n d w a s m e a s u r e d v o l u m e t r i c a l l y o r i n a f l u m e a f t e r p a s s i n g t h r o u g h a n e g g - c r a t e

t y p e b a f fl e t o r e d u c e t u r b u l e n c e . F o r e a c h t e s t ai r w a s i n j e c t e d i n t o o n e o f e i g ht 1 . 2 5 - c m

h o l e s a t 1 5 - c m i n t e r v a ls i n t h e v e r ti c a l r is e r, w h i l e t h e o t h e r s e v e n h o l e s w e r e p l u g g e d .


4/14

1 0 0 N. C. Parker , M. A . Su t t l e

w a t e r f l o w w a s m e a s u r e d a s a i r w a s i n j e c te d i n t o t h e 1 - 25 - cm h o l es . A i r

v o l u m e w a s r e g u l a te d w i th a se r ie s o f r o t a m e t e r t y p e fl o w g a u g e s (D w y e r

I n s t r u m e n t s I n c ., M i c h i g a n C i ty , I n d i a n a , U S A ) , a n d a d j u s te d f r o m 2 8 t o

2 2 4 l it e rs m i n - 1. V a l u e s w e r e n o t c o r r e c t e d t o s t a n d a r d t e m p e r a t u r e a n d

a t m o s p h e r i c p r e s su r e ( ST P ) c o n d i t i o n s ; m e a s u r e m e n t s w e r e m a d e w h e n

w a t e r a n d a i r t e m p e r a t u r e w a s a b o u t 2 0 - 2 5 C . R e p o r t e d a ir f lo w v al ue s

m a y h a v e a 7 - 8 % e r r o r a s c o m p a r e d w i t h v a lu e s at S T P c o n d i t io n s . A i r

w a s in j e c t e d a t o n l y o n e d e p t h a t a t im e w h i l e t h e o t h e r 1 .2 5 -c m h o l e s

w e r e p l u g g e d . F o r a i r l if t p u m p s 3 .7 5.--1 0 c m i n d i a m e t e r , w a t e r f l o w w a s

m e a s u r e d b y v o l u m e t r ic d i s p l a c e m e n t d u r i n g a t i m e d i n te r v a l. F o r a i r li ft

p u m p s 1 5 - 3 0 c m i n d ia m e t e r, w a t e r f lo w w a s. m e a s u r e d i n

P a l m e r - B o w l u s f l u m e s ( m a n u f a c t u r e d a n d c a l ib r a t e d b y P l a s t i c -F a b In c .,

. s f

P l a s t i c b a g

~ ' ~ P u m p

d i s c h a r g e

F i g . 2 . A r r a n g e m e n t o f p l a s ti c b a g f o r c o l le c t i o n o f a ir li ft p u m p d i s c h a r g e f o r

v o l u m e t r i c m e a s u r e m e n t . T h e b a g w a s q u i c k l y s l i p p e d u n d e r t h e l o w e r e d g e o f t h e

d i s c ha r ge p i pe ( A ) a nd a r r a n ge d t o a l low e s c a p e o f a i r a s d i s c ha r g e fi ll ed t he ba g ( B).


5/14

Air l i f t pu m ps for water c ircu la t ion an d aerat ion 101

T u a l a t in , O r e g o n , U S A ) . W a t e r d e p t h i n t h e f lu m e w a s m e a s u r e d a n d

f l o w r a t e s w e r e t a k e n f r o m t a b l e s p u b l i s h e d b y G r a n t ( 1 9 7 9 ) . A l l

m e a s u r e m e n t s o f w a t e r a n d a i r r e p r e s e n t t h e m e a n o f t h r e e in d e p e n d e n t

m e a s u r e m e n t s m a d e a t a p p r o x i m a t e l y 5 - m i n i n te r v a l s a f te r f lo w s w e r e

s t a b i l i z e d .

W e a n a l y z e d a ll d a t a u s i n g H e w l e t t -P a c k a r d s o f tw a r e p a c k a g e s i n a

H e w l e t t - P a c k a r d - 9 8 4 5 c o m p u t e r . B e s t- f i t e q u a t i o n s w e r e s e le c t e d f r o m

l i n e a r , l o g a r i t h m i c , e x p o n e n t i a l , a n d p o l y n o m i a l r e g r e s s i o n m o d e l s t o

p r e d i c t w a t e r f lo w r a te s w h e n a i r f lo w v a r ie d o v e r t h e r a n g e o f 2 8 - 2 2 4

l it e rs m i n -

F l o w r a t e s w e r e c a l c u l a t e d w i t h l i n e a r , l o g a r i t h m i c , e x p o n e n t i a l , a n d

p o l y n o m i a l r e g r e s s i o n e q u a t i o n s f o r a i r v o l u m e s u p t o 1 4 1 6 l it er s m i n - ].

P r o j e c t e d w a t e r f l o w ra t e s a t a i r f lo w s a b o v e 2 2 4 l it e rs m i n - ] ( u p t o

1 4 1 6 l it er s r a i n - ~ w e r e t h e n v e r i fi e d in 5 a n d 1 0 c m d i a m e t e r p i p e s b y

i n c r e a s in g th e a i r v o l u m e f r o m 2 2 4 t o 1 1 3 8 l it er s m i n -~ a n d m e a s u r i n g

A i r F l o w ( c u b i c f e e t p e r m i n u t e )

1 5 1 0 5 0

l l

6 0 3 . 7 5 c m A 4 0

B

~ " 8 0 2 0

I

E 0 P - - - ~ , . . . . . . . . . . . . . 0

ce 2 5 1 0 0 2 5 0 1 0 0 0 la

1 5 l O s o

- L

. . . . . . . . . . . . . .

2 4 0 f 5 c m _ A 6 0 ca

c .

7 . .

1 8 o I 4 o

; .

0 0

2 5 1 0 0 2 5 0 1 0 0 0

A i r F l o w ( l i t e r s m i n - 1 )

F i g . 3 . W a t e r f l o w ra t e s i n a ir li ft p u m p s w i th d i a m e t e r s o f 3 . 7 5 c m ( u p p e r p a n e l ) a n d

5 .0 c m ( l o w e r p a n e l ) w h e n a i r w a s i n j e c te d i n t o t h e v e r t ic a l r i se r a t d i f fe r e n t d i s t a n c e s

( c m ) b e l o w t h e s u r f a c e o f t h e w a t e r : 1 2 0 ( A ) , 1 0 5 ( B), 9 0 ( C ) , 7 5 ( D ) , 6 0 ( E ) , 4 5 ( F ) , 3 0

/ G ). a n d 1 5 (H ) . A l l m e a s u r e m e n t s w e r e m a d e w i th th e f lo w - l i n e o f t h e d i s c h a r g e

1 .2 5 c m a b o v e t h e s u r f a c e o f t h e w a t e r .


6/14

1 0 2 N . C

P ar k er , M . A . Sun l e

w a t e r flo w . T h e e f fe c t s o f d e p t h o f s u b m e r g e n c e a n d v e r t ic a l l if t w e r e

a l s o e v a l u a t e d . A i r a t a f lo w r a t e o f 8 5 l it e r s m i n - 1 w a s i n j e c te d i n t o a i r-

l if t p u m p s w i th d i a m e t e r s o f 5 0 , 7 -5 a n d 1 0 c m a t a d e p t h o f 6 0 c m

b e l o w t h e c e n t e r - l in e o f th e d i s c h a r g e fr o m t h e p u m p . U n d e r t h e s e c o n -

d i t io n s , fl o w r a t e s w e r e m e a s u r e d w h e n t h e c e n t e r - l i n e o f t h e a i rl if t d i s-

c h a r g e w a s a t t h e s u r f a c e o f th e w a t e r a n d w h e n e l e v a t e d 2 .5 , 5 0 , 7 .5 , 1 0

a n d 1 2.5 c m a b o v e t h e s u r fa c e o r s u b m e r g e d 2.5 o r 5 .0 c m b e l o w t h e

s u rf a ce . T h e m a x i m u m s u b m e r g e n c e w a s l im i te d t o s l ig h t ly le s s t h a n t h e

d i a m e t e r o f t h e a i r li f t p u m p t e s te d ; a t n o t im e w a s t h e t o p o f t h e

d i s c h a r g e p i p e c o m p l e t e l y s u b m e r g e d . V o l u m e t r i c m e a s u r e m e n t s w e r e

m a d e d u r i n g t h e s u b m e r g e n c e t e st s b y c o l le c t in g a ir li ft d i s c h a rg e s i n

l a r g e p l a s t i c b a g s ( w i t h t o p s o p e n t o a l l o w a i r t o e s c a p e ) h e l d u n d e r t h e

d i s c h a r g e p i p e s ( F ig . 2).

R E S U L T S A N D D I S C U S S I O N

L o g a r i t h m i c r e g r e s s i o n p r o v i d e d t h e b e s t - f i t m o d e l f o r e m p i r i c a l l y

d e r i v e d w a t e r f lo w r a t e s f o r a ir l i f t p u m p s ; d a t a w e r e p l o t te d o n a s e m i l o g

5 0 O

4 0 0

o

t . .

0

3 0 0

2 0 0

0

1 0 0


1 5 1 0 5 0

, , . , . . l . , , i A

7 . 5 c m /

B

C

D

E

F

G

1 4 0

1 2 0 1

I O 0

m

C

8 0 o

6 0

I

, o i

@

I

2 5 1 0 0 2 5 0 1 0 0 0

A i r F l o w ( l i t e r s r a in 1 )

F i g . 4 . W a t e r f l o w r a te s in a n a ir l i f t p u m p 7 -5 c m i n d i a m e t e r , w h e n a i r w a s i n j e c te d

i n t o t h e v e r t i c a l r i s e r a t d i f f e r e n t d i s t a n c e s ( c m ) b e l o w t h e s u r f a c e o f t h e w a t e r : 1 2 0 ( A ) ,

1 0 5 ( B ), 9 0 ( C ) , 7 5 ( D ) , 6 0 ( E ) , 4 5 ( F ) , 3 0 ( G ) , a n d 1 5 (H ) . A l l m e a s u r e m e n t s w e r e m a d e

w i t h t h e f lo w - l in e o f th e d i s c h a r g e 1 -2 5 c m a b o v e t h e s u r f a c e o f t h e w a t e r .


7/14

A i r l i f t p u m p s o r w a t er c i r c u l a ti o n a n d a er a t i on

1 0 3

s c a l e (F i g s 3 - 9 ) . F l o w r a te s i n 5 a n d 1 0 c m d i a m e t e r p i p e s w i t h ai r f l o w s

o f 2 8 - 2 2 4 l it er s m i n - 1 w e r e u s e d t o p ro j ec t w a te r f l o w b e y o n d t h e r an g e

of the in i t i a l t e s t . T he pred ic ted f l ow ra te s w ere ver i f i ed in add i t iona l

l a b o r at o r y t e st s o f 5 a n d 1 0 c m d i a m e t e r p i p e s w h e n a i r f l o w w a s 1 1 3 8

l i ters min-1 . In a ir l i f t s o f a l l s i zes , f low rates increased as e i ther a ir f low,

t h e d e p t h o f a i r i n j e c t i o n , o r b o t h , i n c r e a s e d . T h e n o - f l o w c o n d i t i o n s

d e s c r i b e d b y M u r r a y

e t a l

( 1 9 8 1 ) w e r e n o t a p p r o a c h e d in o u r t es t e v e n

i n th e s m a l l -d i a m e t e r p i p e s . A n i n c r e a s e i n air f l o w r a te in c r e a s e d w a t e r

f low ra te in a l l s i ze pumps even though the increase w as s l i ght in smal l -

d i a m e t e r p i p e s .

S l ight d i f f erences in submergence o f a i r l i f t pumps a l t ered w ater f l ow

rates s ign i f i cant ly . Water f l ow w as h ighes t w hen the center - l ine o f the

d i s c h a r g e w a s a t o r s li g h tl y b e l o w t h e s u rf a c e o f th e w a t e r ( F ig s 1 0 - 1 2 ) .

F l o w s d e c r e a s e d a s t h e d i s c h a r g e w a s e l e v a t e d a b o v e t h e w a t e r s u r f a c e .

P icker t (1932 ) caut ioned that on ly f l ow s f rom a ir l i f t s o f ident i ca l

s u b m e r g e n c e a n d l e n g t h c o u l d b e c o m p a r e d w i t h e a c h o t h e r . R e c o g n i z -

i n g t ha t c a u t i o n , w e c o m p a r e d t h e f l o w r a te s o f o u r 3 . 7 5 c m d i a m e t e r a ir -


1 5 10 50

6 0 0 . . . . . . . . . . . . . .

10 cm

1 4 0

s o o

C

_ 1 2 0 E

4 0 0 E ,-,

100 =

c

F 0

30 0 . G 80

o

u .

6 0

; 2 0 0 o

(u 4 0 u .

1 0 0

2 0

0 0

2 5 1 0 0 2 5 0 1 0 0 0

A i r F l o w ( l i t e r s

r a i n - 1 )

F i g .

5 .

W a t e r f l o w r a te s in a n a i rl if t p u m p 1 0 c m i n d ia m e t e r w h e n a ir w a s i n j e ct e d i n t o

t h e v e r t i c a l r i se r a t d i f f e r e n t d i s t a n c e s ( c m ) b e l o w t h e s u r f a c e o f t h e w a t er :

120 (A) , 105

(Bt , 90 (C), 75 (D), 60 (E) , 45 (F) , a n d 30 (G). A l l m e a s u r e m e n t s w e r e m a d e w i t h t h e

f l o w - l i n e o f th e d i s c h a r g e 1 . 2 5 c m a b o v e t h e s u r fa c e o f t h e w a t er .


8/14

1 0 4

1 0 0 0

N. C. Parker , M. A . Su t t l e

A l r F l o w

( c u b i c f e e t p e r m i n u t e )

1 5 1 0 5 0

1 8 0

:40 , .

8 0 0 E

. - " , ,oo ;

0 O .

' - m

S ,-

e 6 0 0 6 0 o

01

, * o t

_ v

2 0

4 0 0 o

O

I k

; ~o ;

e

2 0 0

~0

O

2 5 1 0 0 2 5 0 1 0 0 0

A i r F l o w ( l i t e r s

r a i n " 1 )

Fig. 6 . W ater f low ra tes in an a ir li ft pu m p 15 cm in diam eter wh en a ir was injected in to

the v ert ical r iser a t different distances (cm ) below th e surface o f the w ater: 120 (A ), 105

(B), 90 (C) , 75 (D ) , 60 (E) , 45 (F), an d 30 (G) . Al l measurements were m ade w i th the

f low -line of the di scharge 1 .25 cm above the surface of the w ater .

l i f t p u m p w i t h a i r i n j e c t e d a t 7 3 l i t e r s m i n - l, 6 0 a n d 1 2 0 c m b e l o w t h e

s u r f a c e ( F ig . 3 ) w i t h f l o w r a t e s r e p o r t e d b y C a s t r o a n d Z i e l in s k i (1 9 8 0 ) .

O u r f l o w r a te s w e r e 5 1 a n d 7 7 l i te r s m i n - l, r e s p e c t i v e ly , f o r t h e 6 0 a n d

1 2 0 c m d e p t h o f a i r i n j e c t i o n , c o m p a r e d w i t h t h e ra t e s o f 7 3 a n d 9 8

l i t e r s m i n - ~ r e p o r t e d b y C a s t r o a n d Z i e l i n sk i . T h e s e d i f fe r e n c e s w e r e

p r o b a b l y d u e t o d i f f e r e n c e s i n s u b m e r g e n c e . O u r m e a s u r e m e n t s w e r e

m a d e w i th t h e b o t t o m o r f l o w - l i n e o f t h e d i s c h a r g e p i p e 1 .2 5 c m a b o v e

t h e s u r fa c e o f th e w a t e r . C a s t r o a n d Z i e l i n s k i m e a s u r e d f l o w a t 1 0 0 %

s u b m e r g e n c e , p r e s u m a b l y w i t h t h e c e n t e r - l i n e o f th e d i s c h a r g e p i p e a t

t h e s u r f a c e o f th e w a t e r .

T h e f lo w r a t e s p r e s e n t e d i n F ig s 3 - 9 a r e a b o u t 1 0 - 4 0 % l e ss t h a n th e

m a x i m u m f l o w s o b t a i n a b l e f r o m a ir li f ts o f s i m i l a r s iz e w i th s i m i l a r ra t e s

o f a ir i n j e c t i o n . F o r e x a m p l e , in a 5 c m d i a m e t e r a i r l i f t o p e r a t e d w i t h 8 5


9/14

1 0 0 0

Airl i f t p u m ps for water c irculat ion an d aeration


1 5 1 0 5 0

8 0

4 0

8 0 0 E

- o o ;

C

m 6 0 0 6 0 _

~ 2 0

4 0 0 o

0

D

o ;

2 0 o

o

1 0 5

C

2 5 1 0 0 2 5 0 1 0 0 o

A i r F l o w ( l i t e r s m i n 1 )

F i g . 7 . W a t e r fl o w ra t e s in a n a i rl if t p u m p 2 0 c m i n d i a m e t e r w h e n a i r w a s i nje c te xi i n t o

t h e v e r t ic a l r i s e r a t d i f f e r e n t d i s t a n c e s ( c m ) b e l o w t h e s u r f a c e o f t h e w a t e r : 1 2 0 ( A ) , 1 0 5

(B ), 9 0 ( C ) , 7 5 ( D ), 6 0 ( E ), 4 5 ( F ) , a n d 3 0 ( G ) . A l l m e a s u r e m e n t s w e r e m a d e w i t h t h e

f l o w - l in e o f th e d i s c h a r g e 1 .2 5 c m a b o v e t h e s u r f a c e o f t h e w a t e r .

l it er s m i n - ~ o f a ir i n j e c t e d a t a d e p t h o f 6 0 c m b e l o w t h e c e n t e r - l i n e o f th e

d i s c h a r g e , t h e f l o w r a te w a s a b o u t 1 2 % g r e a t e r w h e n t h e v e r ti c a l l i f t w a s

z e r o t h a n w h e n i t w a s 1 .2 5 c m ( F ig . 1 0 ). T h e f lo w i n a 7 -5 . c m d i a m e t e r

a ir li ft i n c r e a s e d a b o u t 1 6 % w h e n t h e v e r t ic a l l i f t w a s r e d u c e d f r o m 1 .2 5

c m t o z e r o ( F ig . 1 1 ). C h a n g i n g t h e v e r t i c a l l i ft i n a 1 0 c m d i a m e t e r a ir l i ft

f r o m 1 .25 t o z e r o i n c r e a s e d f lo w s a b o u t 3 8 % (F ig . 12) . T h e d e p t h o f

s u b m e r g e n c e o r , c o n v e r s e l y , t h e v e r t i c a l l i f t , a f f e c t e d f l o w r a t e s i n

p r o p o r t i o n t o t h e d i a m e t e r o f t h e a ir l i f t. T h e e f fe c t o f c h a n g e i n d e p t h o f

s u b m e r g e n c e o n f lo w w a s o n l y s l ig h t i n s m a l l - d i a m e t e r a ir l i f t s , b u t w a s

v e r y s u b s t a n t i a l i n l a r g e - d i a m e t e r p ip e s .

I n o u r t e s t , f l o w r a t e s i n 7 . 5 c m a i r l i f t p u m p s w e r e i n c r e a s e d a b o u t

5 - 1 0 % w h e n a ir w a s in j e c te d t h r o u g h a s e r i e s o f 1 . 6 - m m h o l e s a r o u n d

t h e p i p e r a t h e r t h a n t h r o u g h a s i n g le 1 . 2 5 -c m h o l e . H o w e v e r , th e


10/14

1 0 6

N. C. Parker , M. A. Sut t le


1 5 1 0 5 0

1 2 0 i

1 2 0

~ a o

. - " 1 0 0 1

c

, E

C

- - ~ 4 0

S ;

I I L

e l

, - 8 0 1

0 0

" 0

v

]= 6 0 ~ 6 0 ~=a

o

u. I

o

2 0 - -

u.

4 0 1

2 0 t

| o

L . )

2 5 1 0 0 2 5 0 1 0 0 0

A i r F l o w ( l i t e r s r a i n " 1 )

Fig. 8. Water low rates in an airlift pump 25 cm in diameterwhenair was injected nto

t h e v e r t ic a l r i se r a t d i f f e re n t d i s t a n c e s ( c m ) b e l o w t h e s u r f a c e o f th e w a t e r : 1 2 0 ( A ) , 1 0 5

(B ), 9 0 ( C ) , 7 5 ( D ) , 6 0 ( E ), 4 5 ( F ) , a n d 3 0 ( G ). A l l m e a s u r e m e n t s w e r e m a d e w i t h t h e

f l o w - l in e o f t h e d i s c h a r g e 1 .2 5 c m a b o v e t h e s u r f a c e o f th e w a t er .

increase in flow rate was too small to justify the additional expense or

effort required to provide this radial air injection. Ward (1924), who

tested different types of air injectors, concluded that there should be no

central air injection nozzle or other obstruction to the flow of water. He

found that special devices were not required to mix air with water in

airlift pumps. He also reported that small fine bubbles provided no

advantage because small bubbles quickly coalesced into larger bubbles

as they traveled up through the water column. Threaded holes fitted with

90* hose adaptors have worked well as injection ports in our tests and in

subsequent field applications at this laboratory and in field tests in US

Fish and Wildlife Service National Fish Hatcheries in San Marcos,

Texas; Natchitoches, Louisiana; Edenton, North Carolina; and the

Marion State Fish Hatchery, Marion, Alabama.


11/14

1 0 0 0

Air l if t pum ps fo r w a te r c i rc u la t ion an d ae ra tion


1 5 1 0 5 0

8 0

4 0

A

' E

8 0 0

o o ;

C

6 0 0 6 0 o

0

- 2 0

4 0 0 o

~ ~ 0

2 0 0

o

1 0 7

o j

2 5 l O 0 2 5 0 1 0 0 o

A i r F l o w ( l i t e r s r a i n 1 )

F i g . 9 . W a t e r f l o w ra te s i n a n a i r l if t p u m p 3 0 c m i n d i a m e t e r w h e n a i r w a s i n j e c t e d i n t o

t h e v e r t i c a l r i s e r a t d i f f e re n t d i s t a nc e s ( c m ) b e l o w t h e s u r fa c e o f t h e w a t e r : 1 2 0 ( A ) , 1 0 5

(B ), 9 0 ( C ) , 7 5 ( D ), 6 0 ( E ), a n d 4 5 ( F ). A l l m e a s u r e m e n t s w e r e m a d e w i th t h e fl o w - l i n e o f

t h e d i s c h a r g e 1 .2 5 c m a b o v e t h e s u r f a c e o f t h e w a t e r.

1 0 0

9 0

~ ' - ' 8 0 .

[ ,~ ~ ?0 -

~ : 5 o ,

i

4 0 t

3 0

, ~ C m

-'a ~ ~ i ~ ~ io ,'2 1,

VE RTICAL L IF T ( e r a )

F i g . 1 0 . W a t e r fl o w r a te s i n a n a ir li ft p u m p 5 - 0 c m i n d i a m e t e r , i n t o w h i c h 8 5 l i te r s

m i n - t o f a i r w e r e i n j e c te d 6 0 c m b e l o w t h e c e n t e r - li n e o f t h e d i s c h a r g e , w h i le t h e c e n t e r -

l in e o f t h e a i rl if t d i s c h a r g e w a s b e l o w , a t , o r a b o v e t h e s u r f a c e o f t h e w a t e r .


12/14

1 0 8 N . C . Parker , M. A . Su t t l e

2 o o T

1 2 0 ~ -

x

4 0 i i 12 I ~ p

- ~ ~ ~ 1 'o 1 '4

V E R T I C A L LIFT (cm)

F i g . I I . W a t e r f l o w r a t e s i n a n a i r l i ft u m p 7 . 5 c m i n d i a m e t e r i n t o w h i c h 8 5 l i te r s

r a i n - ~ o f a i r w e r e i n j e c t e d 6 0 c m b e l o w t h e c cn t e r - l i n e o f t h e d i s c h a r g e w h i l e t h e c e n t c r -

l i n e o f t h e ai rl i ft i s c h a r g e w a s b e l o w a t o r a b o v e t h e s u r f a c e o f t h e w a t e r .

2eo T

i0 c m

2 2 0 +

I ~ 1 4 0 .

~ t O O

eo+

2 0 1 J

- 6 - 2 2 6 1 0 1 4

VERTICAL LIFT (cm)

Fig. 12 . W ate r f low ra tes in an a ir li ft pu m p 10 cm in diameter , in to w hich 85 l it e rs

m i n - ~of a i r w ere injec ted 60 cm be low the cente r- line o f the di scharge , whi le the cente r-

l ine of the air li f t discharge w as below , at , or ab ove the su rface of the w ater.

O n t h e b a s is o f t h e c o s t o f m a t e r i a l s , i n s ta l la t io n , a n d o p e r a t i o n , w e

f o u n d 7 .5 a n d 1 0 c m d i a m e t e r a ir l i f t p u m p s t o b e m o r e a p p r o p r i a t e t h a n

e i t h e r l a r g e r o r s m a l l e r o n e s f o r d e s t ra t i fy i n g 0 .0 2 - t o 2 . 0 - h a p o n d s . O n e

a ir li f t p u m p p e r 0 0 2- o r 0 . 0 4 - h a p o n d p r e v e n t e d s t r a t i f i c a t io n w h e n 8 5

l it e rs m i n - t o f a i r w a s i n j e c t e d i n t o t h e v e r t i c a l r i se r a t a p o i n t 6 0 c m

b e l o w t h e s u r f a c e o f t h e w a t e r . I n l a rg e r p o n d s 7 . 5 a n d 1 0 c m d i a m e t e r

p u m p s h a v e b e e n i n s t a l le d a t t h e r a t e o f 25 p e r h a a t t h i s l a b o r a t o r y a n d

i n o t h e r U S F i s h a n d W i ld l i f e S e r v i c e fa c il it ie s .

U n d e r t h e s e c o n d i t i o n s , a r e g e n e r a t i v e b l o w e r ( se e P a r k e r , 1 9 8 3 , f o r

d e s c r i p t i o n o f t y p e s o f b l o w e r s a n d c o m p r e s s o r s ) w i t h a n a m e p l a t e

r a t in g o f 1 k W ( 1 .3 4 h p ) o p e r a t e d 2 7 a i rl if t p u m p s w i t h w a t e r f l o w ra t e s


13/14

Airlift pu m ps for water circulation and aeration

109

o f 1 5 0 - 2 3 0 l it e r s m i n -1 e a c h ; t h e t o ta l c o m b i n e d f l o w ra t es f r o m 2 7

a ir li ft s r a n g e d f r o m 4 0 5 0 t o 6 2 1 0 l it e rs m i n -1 f o r 7 .5 a n d 1 0 c m

d i a m e t e r p u m p s , r e s p e c t i v e l y . V e r t i c a l l if t w a s e s s e n t i a l l y z e r o a s t h e s e

a ir l i f t s w e r e a d j u s t e d f o r m a x i m u m f lo w t o p r o d u c e c i r c u l a t i o n a n d

v e r t ic a l m i x in g o f w a t e r i n p o n d s .

A C K N O W L E D G E M E N T S

W e t h a n k C . S u p p e s , a n d I . Q u i n a t a , M i s s o u r i D e p a r t m e n t o f C o n s e r v a -

t io n , a n d G . C h a m b e r l a i n , T e x a s A & M U n i v e r s i t y , f o r th e i r c r i ti c a l

r e v i e w o f t h e m a n u s c r i p t .

R e f e r e n c e t o t r a d e n a m e s i n th is p a p e r d o e s n o t c o n s ti tu t e e n d o r s e m e n t

b y t h e U S G o v e r n m e n t .

R E F E R E N C E S

A n d e e n , G . B. ( 1 9 74 ) . B u b b l e p u m p s .

Com pressed A i r M ag .

( Ja n u a r y ) , 1 6 - 1 8 .

A p u d , E D . & C a m a c h o , A . S . ( 1 98 0 ) . E f fe c t s o f w a t e r m o v e m e n t a n d a e r a t io n

s y s te m o n t h e s u r v iv a l a n d g r o w t h o f h a t c h e r y b r e d s u g p o ( P e n a e u s

m o n o d o n

F a b r i c i u s ) i n e a r t h e n n u r s e r y p o n d s . A q u a c u l t u r e D e p a r t m e n t , S o u t h e a s t

A s i a n F i s h e r i e s D e v e l o p m e n t C e n t e r , T i g b a u a n , I l o i l o , P h i l i p p i n e s .

Q. Res.

Repo r t , 4

( 3 ) , 1 5 - 1 8 .

C a s t r o , W . E . & Z i e l i n s k i , P . B . (1 9 8 0 ) . P u m p i n g ch a r ac t e r i s t i c s o f s m a l l a ir li ft

p u m p s .

Proc. W orld M aricul ture Soc. ,

1 1 , 1 6 3 - 7 4 .

C as t r o , W . E . , Z i e l i n s k i , P . B . & S an d i fe r , P . A . ( 1 9 7 5 ) . P e r f o r m an ce ch a r ac t e r i s -

t i c s o f a i r l i f t p u m p s o f s h o r t l en g t h an d s m a l l d i am e t e r .

Proc. W orld M ari -

cul ture Soc. ,

6 , 4 5 1 - 6 1 .

G r an t , D . M . ( 1 9 7 9 ) .

O p e n C h a n n e l F lo w M e a s u r e m e n t H a n d b o o k ,

I n s t r u -

m e n t a t i o n S p e c ia l ti es C o m p a n y , L i n c o ln , N e b r a s k a .

l t o , T ., T o i , J . & S a t o m i , Y . ( 1 9 7 4 ) . T h e e f f ec t o f a r ti fi c ia l p o n d w a t e r c i r cu l a t i o n

a n d f e e d i n g o n p r o d u c t i v i ty i n c a r p c u l t u r e p o n d s .

Bu ll . F resh wa ter Fisheries

Res. Lab. (Tokyo),

2 4 ( 2 ) , 6 5 - 7 7 .

I v en s , E . M . ( 1 9 1 4 ) .

P u m p i n g b y C o m p r e s s e d A i r ,

J o h n W i l e y & S o n s , N e w

Y o r k .

M o r r i s s y , N . M . ( 1 9 7 9 ) . E x p e r i m e n t a l p o n d p r o d u c t i o n o f m a i r o n ,

Cherox

t enu i m a nus (

Sm i th ) (D e c a p o d a : P a r a s ta c i d a e ) .

Aquacu l t u re ,

1 6 , 3 1 9 - 4 4 .

M u r r ay , K . R . , P o x t o n , M . G . , L i n f o o t , B . T . & W at r e t, D . W . ( 1 9 8 1 ). T h e d es i g n

a n d p e r f o r m a n c e o f l o w p r e s s u r e a i r lif t p u m p s i n a c l o s e d m a r i n e r e c i rc u l a -

t i o n s y s t em .

Proc . Wo rld Symp. on Aqua cul tu re in He ated Eff luent s an d

Reci rcu la t ion Sys tems,

S t av an g e r , 2 8 - 3 0 M ay , 1 9 8 0 . V o l . I , B e r l i n , W . G er -

m a n y , p p . 4 1 3 - 2 8 .

Ni ck l i n , D . J . ( 1 9 6 3 ) . T h e a i r l i f t p u m p : T h eo r y an d o p t i m i s a t i o n .

Trans. Instr.

Chem. Engrs ,

4 1 , 2 9 - 3 9 .


14/14

110 N. C. Parker, M. A. Suttle

Parke r , N . C . (1979 ) . S t r iped bas s c u l t u re i n con t i nuou s l y ae ra t ed p ond s . Proc.

Sou theastern Assoc. Fish W ildlife Age ncies, 3 3 , 3 5 3 - 6 0 .

Pa rke r, N . C . (1983 ) . A i r l if t pu m ps and o t h e r a e ra t i on t echn i ques . In : Water

qua lity in chan nel caO~sh pon ds,

e d . C . S . T u c k e r , S o u t h e r n C o o p e r a t i v e

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