IS: 9-137- 1978 CODE FOR ACCEPTANCE TESTS FOR CENTRIFUGkL~MIXED FLOW AND AXIAL PUMPS - CLASS C
Therefore;
b) Re"ding._ corn.:ctcd to ;:)55 rpm rl;,,:! a:,follows:
Rate of
H!tldPower£jJic·':'IIC)'Flow
Absorbed
( rn3/h )
( III )( kw )perL~rll
a
50
2 000
49562 1747'5
4000
47'5704'3773<)
6000
43836'9084
8 000
36881'7389
9000
32891'7588( I'llge ~), clill/se 4.2.1 ) --- Substitute the f.>lIowing for the existing clause:
"1.2.1 Contractual Objects oj the Tests - Thetests are intended t<5 ascertain the 'programme ofthe pump and to compare this with the manufacturer's gu"rantee. However, attention is drawnto the facuhat the NPSH test increase the cost
of the test substantially. It shall, therefore, bespecified by the purchaser in order/contract, ifNPSH test is to be conducted (see also Appendix D ).
Where a number of identical pumps arc to bepurchased, and if NPSH test is specified in thecontract, one pump shall be tested as type test,for other tests the method of sampling of pumps
. as per IS: 10572-1983 'Methods of sampling c) Cl1.lracteristic curves Q.V/R H Q.Vh 'r,•...-~ b f I d " •. ', J pumps' shall e olowe . QViR P are drawn o~gra~h CseeBg~.-L!l(~------
----.-----.(-p,a-gr20,cfuwe7-;-l}-=-s-u15Sfltute tne lollow- l5iH~2 Gl, 6. Q = 600 m5fhing for the existing clause;
'7.1 General - When the contract specifies thatNPSH test shall _~e condl!geci .tQ verify whetherNPSH required by the pump is equal to or lessthan the specified/guaranteed NPSH, one of thetest methods as specified in 7.1.1 shall be adoptedto conduct NPSH test.
In no case shall cavitation test be used (Q
check that the pump shall be fr~e from cavitational erosion during its service life.'
(PagJ '24. clal/se 9.2.1, Ihird para aJter tfJicientr
trallslatioll ) - Substicute the following for theexisting matter: "
'If nop exceeds 20 percent variation. it shallbe necessary to apply corrections all efficiency asgiven in 5.3. The stipulation for fl, Q. andNPSH shall remain according to 9.2.1 irrespective of lisp variations.'
[Page 26, clause 9.6 (see also. Amendmmt
No. I ) I - i\dd the following examples in 9.6:
Exam/'!e 3:
\Vhell pump fails to meet the guaranteedpower inpilt to the pump:
a) Guaranteed duty nJ pump:
= Q'6 724 + (j49
= 1'162-1
Hence tl\(; pilInp ch:'.racteristics is W;:;l l'. the acceptable limits.
d) The duty point ( 6000 mS/h, 41 In) isconnected to (0,0) and the intersccti(Jl,of this line with the characteristic cun'c s
determined which being 6 200 mSih, 42 r: •.This duty considered as the actual PUIn,>duty has an efficiency of 8{'5 percent.
e) Permissible lower limit on guaranteeddJieieney (0'95 x 0'85 ) = 0'807 5, t1':'lis, 80 75 percent. Since actual pump driciene}' is 8-{'5 percent this is also withinacceptable limits.
~apacit\'
Total head
Speed
EfT!cir.ncy
Power input to pump at.(Ill" 11111111
G 000 m3/h
41 m
555 r[lm
85 percent
78!.H kW
f) The power input to the pump ',\'ithill t:llrange defined in 9.1.1 by the to]eranc,:,-+,Xc) and +..\'Il is 336'9 to 852'4 k.W .. \,;;gre~d bet;een the manufacturer and thtpurchaser the power should not exec"'!B'28 k\V. Since the power input within th.'range exceeds 828 k\V, the pump f;jils IIIIII"" till' III 1\\",'1 "'11":' 1111\ Ill' '11 ,
.J. I./f.,'l
..
fF' ' '-~H~~--' , ", 'I ., I I J :h'=1='_-t-+--+-+ -1-- . ; I ' r- -I--f- r--~- I -j ---j --
40 1- _l . ,-, J,t lfli-~-41-+i:-~
-!-_ L- I I ! '.~oK ,I I , -ri- I '
n.
i--I I /' ,,:\ ~_+ 6CV' 1- I I
~I : I I
3- -j~
oX
20 I/,' ~/'12000V" UJ
0/' ro
a:a•...
I 800~-
.<('~•... a:
100400 UJ30c.
80
l/
60
--
I. >- /~ 40 tLlIIU :
:"1-
III '1=,u. 20II
I! ! I iIi ,-t+-u y.I I.!j- I II ,' I I---l- -1, I II Ii I I i !
II i II II I I I+I I)
0I II : II I : I
o 50 100 150 200 250
RATE OF FLOW IN m3ih (0)
300
D. H = 2'0 m
D. Q = 600 mSjh
Guaranteed Duty = 6000 mSih x 41 m x 7R8'6 kW ~\ 555 rpm
Actual Duty = 6200 m'jh x 42 m X 839'7 kW at 555 'pm
FIG. 10C CHARACTERISTIC CURVE FOR PUMP OF GUARANTEED DUTY OF 6 000 m~!hDISCHARGE X 41 IT} HEAD
r~' __J
ExamPle .}:
\Vh.:n pump fails to meet the guaranteedefficiency point:
20
3G
47
54
61
5815
percent
~1'88
10'22
108711'6
11'72
11·98
12·8
b) Readings corrcctcd 10 1180 ,p'" rwd as fulioll'J':
'T'l - (No X XI! ')1 (Qo X XQ \1'lcrelore ,----- + ---- I6H ,6C2.J
- (' /-5 x ().n4,)'s" (' 300 X 0'07)'= -~CO--- + 20'
= (l-()g + 1'1025 = 1'1925
H'O m). This duty considered as theactual pump duty has an efficiency of;;0 percent.
e) Permissible lower limit on guarantee ddncicncy ( 0-54- X 0,95 ) = 0'513, that ;s,.')1,3 percellt. Since the actual efficienc yis 50 percent the pump fails .to meet tl-tguaranteed efficiency.
Hence, the pump' characteristics. is withinacceptable limits.
<1) The duty point (300 mB/h, 7'5 m) isconnected to ( 0,0 ) and the intersection ofthe line with the characteristic curve isdetermined which being (317'5 m/h,
f) The power input to the pump within therange defined in 9.4.1 by the tolerance±XQ and ±XH is 11'98 kW to 13'35 kW.Since the power input as agreed betweenthe manufacturer and the purchaser lieswithin this range, the power consumptiollis'within acceptable limits. '
25
20'
15
10
5
o
70
60~ 50>~ £.0wg 3QlJ..~ 20
100
H=+---L--u T J T T
,::,-_~ j-U' I m::D=_ :::t':::'- - =f~L'-'-m' T '1l__ =+= L--- --'- T='- =, , i----==' T t
