IS 14740: Pneumatic Fluid Power - Components Using Compressible Fluids - Determination of Flow-rate Characteristics

20 Pages·1999·1.6 MB·English

by  Bureau of Indian Standards

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IS 14740 (1999): Pneumatic Fluid Power - Components Using
Compressible Fluids - Determination of Flow-rate
Characteristics [PGD 16: Fluid Power]
“!ान $ एक न’ भारत का +नम-ण”
Satyanarayan Gangaram Pitroda
““IInnvveenntt aa NNeeww IInnddiiaa UUssiinngg KKnnoowwlleeddggee””
“!ान एक ऐसा खजाना > जो कभी च0राया नहB जा सकता हहहहै””ै”
Bhartṛhari—Nītiśatakam
“Knowledge is such a treasure which cannot be stolen”

IS14740:1999
IS0 6358 : 1989

Indian Standard
PNEUMATIC FLUID POWER - COMPONENTS
GNISU COMPRESSIBLE FLUIDS - NOITANIMRETED
FO FLOW-RATE CHARACTERISTICS
ICS 23.100.01

0 SIB 1999
BUREAU OF INDIAN STANDARDS
MANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG
NEW DELHI 110002

November 1999 Price Group 7
citamuenP diulF rewoP smetsyS lanoitceS ,eettimmoC PE 61
LANOITAN FOREWORD
sihT naidnI dradnatS hcihw si lacitnedi htiw 0SI 8536 : 9891 citamuenP‘ diulf rewop - stnenopmoC gnisu
elbisserpmoc sdiulf - noitanimreteD of etar-wolf ’scitsiretcarahc deussi yb eht lanoitanretnI noitazinagrO for
noitazidradnatS ( 0SI ) saw detpoda yb eht uaeruB of naidnI sdradnatS no eht noitadnemmocer of eht -uenP
citam diulF rewoP smetsyS lanoitceS eettimmoC ( PE 61 ) dna lavorppa of eht noitcudorP gnireenignE -iviD
nois .licnuoC
nI citamuenp diulf rewop ,smetsys rewop si dettimsnart dna dellortnoc hguorht a sag rednu erusserp nihtiw a
.tiucric stnenopmoC gnisopmoc hcus a tiucric era yltnerehni evitsiser dna affect eht wolf hguorht .ti tI ,si
,erofereht yrasecen ot yrrac tuo stset ot niatrecsa eht scitsiretcarahc of eseht stnenopmoc ni redro -reted~ot
enim rieht .ytilibatius ynaM stnenopmoc gnisopmoc a citamuenp tiucric etarepo rednu snoitidnoc of dekohc
.wolf sihT dradnats seificeps stset ta dekohc wolf ni noitingocer of eseht .snoitidnoc
nI eht detpoda ,dradnats niatrec ,ygolonimret snoitnevnoc dna dohtem of noitatneserp era ton lacitnedi ot
esoht desu ni naidnI .sdradnatS noitnettA si ylralucitrap nward ot :gniwollofeht
)a reverehW eht sdrow lanoitanretnI‘ raeppa’dradnatS gnirrefer ot siht ,dradnats yeht dluohs eb daer sa
naidnI‘ .dradnatS
)b Comma ( , ) sah neeb desu sa a lamiced rekram elihw ni naidnI sdradnatS eht tnerruc ecitcarp si ot
esu a tniop ( . ) sa eht lamiced .rekram
nI siht detpoda dradnats ecnerefer sraeppa ot niatrec lanoitanretnI sdradnatS for hcihw naidnI sdradnatS osla
.tsixe ehT gnidnopserroc naidnI sdradnatS hcihw era ot eb detutitsbus ni rieht ecalp si detsil woleb gnola htiw
rieht eerged of ecnelaviuqe for eht snoitide :detacidni
lntefnational Standard Corresponding Indian Standard Degree of
Equivalance
0SI l-822 : 4991 epiP sdaerht SI 3462 : 5791 snoisnemiD for epip sdaerht for yllacinhceT
erehw erusserp thgit stnioj era gninetsaf sesoprup : traP 1 cisaB eliforp dna tnelaviuqE
ton noedam eht 1traP-sdaerht : ,snoisnemid traP 2 ,secnareloT traP 3 stimiL of

,snoisnemiD secnarelot dna sezis

noitangised
0SI 162 : 8991 0SI lareneg SI 8124 ( traP )2 : 6791 0SI cirtem wercs od
esoprup cirtem wercs sdaerht - sdaerht : traP 2 retemaiD hctip snoitanibmoc ( first
lareneG nalp revision )
0SI 8955 : 5891 diulF rewop SI 61401 : 2991 diulF rewop smetsys dna lacitnedI
smetsys dna stnenopmoc - stnenopmoc yralubacoV- ( first revision)
vocabulary
ehT lacinhcet eettimmoc elbisnopser for eht noitaraperp of siht sah-dradnats deweiver eht snoisivorp of eht
gniwollof 0SI dradnats dna sah dediced taht ti si elbatpecca for esu ni noitcnujnoc htiw siht :dradnats
1891:9711OSI epiP ,snoitcennoc dedaerht ot 0SI )l-822 for nialp dne leets dna rehto latem sebut
ni lairtsudni snoitacilppa
roF eht esoprup of gnidiced rehtehw a ralucitrap tnemeriuqer of siht dradnats si deilpmoc ,htiw eht lanif ,eulav
devresbo ro ,detaluclac gnisserpxe eht tluser of a ,tset llahs eb dednuor off ni ecnadrocca htiw SI 2 0691:
seluR‘ for gnidnuor off laciremun seulav (revised)‘. ehT rebmun of tnacifingis secalp deniater ni eht dednuor off
eulav dluohs eb eht emas sa taht of eht deificeps eulav ni siht .dradnats
IS 14740 : 1999
IS0 6356 : 1969
lndian Standard
PNEUMATIC FLUID POWER - COMPONENTS
GNISU COMPRESSIBLE FLUIDS - NOITANIMRETED
FO FLOW-RATE CHARACTERISTICS
1 Scope 2 Normative references
This International Standard specifies a method for testing The following standards contain provisions which, through
pneumatic fluid power components which use compressible reference in this text, constitute provisions of this International
fluids, i.e. gases, to enable their flow-rate characteristics under Standard. At the time of publication, the editions indicated
steadv-state conditions to be compared. were valid. All standards are subject to revision, and parties to
agreements based on this International Standard are encouraged
It specifies requirements for the test installation, the test pro- to investigate the possibility of applying the most recent editions
cedure and the presentation of results. of the standards listed below. Members of IEC and IS0 main-
tain registers of currently valid International Standards.
Accuracy of measurement is divided into two classes (A and B)
which are explained in annex A. IS0 228-l : ,2891 Pipe threads where pressure-tight hints are
not made on the threads - Part 1: Designation, dimensions
General background information is given in annex B and the
and tolerances.
basic theoretical equations are given in annex C. Guidance as
to the use of practical units for the presentation of results is
given in annex D. IS0 261 : 1973. IS0 general purpose metric screw threads -
General plan.
This International Standard generally applies to those fluid
power components up to and including 20 mm nominal bore IS0 1179 : 1961, Pipe connections, threaded to IS0 228- 1, for
used with compressible fluids (gases), the internal flow plain end steel and other metal tubes in industrial applications.
passages of which remain constant during testing. Examples of
such components are
IS0 5596 : 1985, Fluid power systems and components -
Vocabulary,
a) directional control valves, flow control valves, quick
exhaust valves, etc. ;

b) moving part logic devices.
3 Definitions
It ay also apply to components larger than 20 mm nominal
bo“rea ut this may require the provision of exceptionally large
flow generating equipment. For the purposes of this International Standard, the definitions
given in IS0 5598 and the following definitions apply. It should
Two test methods are~described according to the type of com- be ~borne in mind, however, that the following definitions
ponent. There are also two sets of characteristic constants : C may differ from those given in other specific International
and b; and A and s, respectively (as defined in 3.2 to 3.5). Standards.
These may be calculated from the results.
The first set of characteristics (C and b) applies to cases where 3.1 choked flow: Occurrence when upstream pressure, pl,
comparison of similar components is required, or when calcu- is high in relation to the downstream pressure, ~2, such that
lations of pressure and flow involve a single component only. the velocity in some part of the component becomes sonic. The
mass flow of the gas is proportional to the upstream pressure,
The second set of characteristics (A and s) is necessary when pl, and independent of the downstream pressure, p2.
the flow behaviour of several components which are con-
nected in series is to be estimated. This set may also be used as
an optional alternative to the first set for simple flow calcu- 3.2 cr2tical pressure ratio, b: Pressure ratio @2/p,) below
lations and for comparison of components. which flow becomes choked.
This International Standard does not apply to components
which exchange energy with the fluid (gas), for example 3.3 sonic conductance, C: Mass flow rate through the
cylinders, accumulators, etc. component, q;, divided by the product of the upstream
1
IS 14740 : 1999
IS0 6356 : 1969
pressure, pl, and the mass density at standard conditions ~0 4.2 The numerals used as subscripts and the asterisk (“1 used
(see table 2) when the flow is choked, I.e. as a suRerscript to the symbols listed in table 1 are as specified
in table 2.
4%
c=_ atT= To
eo PI
Table 2 - Subscripts and superscripts
NOTE - The numerical value of C depends upon the values chosen for Super- Sub-
Meaning
the standard reference atmosphere. script script
0 Standard reference conditions, i.e. :
To = 293,15 K;
3.4 coefficient of compressibility effect, s: Coefficient op =
100 kPa (1 barth
which takes into account the effects of the gas compressibility
65 % relative humidity
when flow is subsonic (see 0.2.3).
1 Upstream conditions
2 Downstream conditions
3.5 effective area, A : Mass flow rate throughout the com-
ponent, ,,,,q divided by the squareroot of twice the product of l Conditions during sonic flow tests
the pressure drop, Ap. and the mass density of the gas ~2, i.e. 1) 1 bar = 166 kPa = 0,l MPa; 1 Pa = 1 N/m2
Qm
A=
JZGG 4.3 The graphical symbols used in figures 1 and 2 are in ac-
cordance with IS0 1219.
This applies only when the pressure drop is small in relation to
1p such that compressibility effects are insignificant, i.e. when
ApIp, < g,g2.
5 Test installation
4 Symbols and units 5.1 Test circuit for components with inlet and
outlet ports
4.1 The symbols and units used throughout this International
A suitable test circuit as shown in figure 1 shall be used.
Standard are as shown in table 1.
Table 1 - Symbols and units
5.2 Test circuit for components which exhaust
directly to atmosphere
efer- Sym- SI
Nnce Description bol Dim ensiont) units21
A suitable test circuit as shown in figure 2 shall be used.
3.5 Effective area A L2 m2
3.2 Critical pressure ratio b pure number NOTE - Figures 1 and 2 illustrate basic circuits which do not incor-
3.3 Sonic conductance C L”TM -1 s.m4/kg porate all the safety devices necessary to protect against damage in the
event of component failure. It is important that those responsible for
- Absolute static pressure carrying out the test give due consideration to safeguarding both per-
(equal to the relative sonnel and equipment.
static pressure plus the
atmospheric pressure) P ML-‘T-2 Pa31
- Mass flow rate Qm MT-’ kg/s
5.3 General requirements
- Volume flow rate at
standard conditions Qv L3T-1 m3/s
5.3.1 The test components shall be installed and operated in
- Gas constant (for a
the test circuit inaccordance with the manufacturer’s operating
perfect gas) R L2T-20-l J/fkg.KI
instructions.
3.4 Coefficient of com-
pressibility effect s pure number
- Absolute temperature T 0 K 5.3.2 A filter shall be installed which provides a standard of
- Pressure drop 1~( - ~2) Ap ML-‘T-2 Pa31 filtration approved by the test component manufacturer.
- amass density Q ML-3 kg/m3
1) M = mass; L = length ; T = time; 0 = temperature 5.3.3 A test set-up shall be constructed from the items listed
in table 3.
2) The use of practical units for the presentation of results is
described in annex D.
NOTE - Items A to H inclusive are essential and the remaining items I
3) 1 Pa = 1 N/m2
to L are chosen by the experimenter to suit the prevailing conditions.
2
A c v
B D F G H K L
Figure 1 - Test circuit for components with irilet and outlet ports ‘)
I
E
-

>

I
>lOd, IOd,
c
B c L D F
Figure 2 - Test circuit for components which exhaust directly to atmosphere ‘)

0 1) See table 3 for key to circuit items.
IS 14740: 1999
IS0 6356 : 1969
Table 3 - Key to test circuit components
Relevant
Reference
sub- Description Comments
letter
clause(s)
A 53.2
Compressed gas source and filter
6.1.1.2
B - Adjustable pressure regulator
C - Shut-off valve Preferably with straight flow path
D 5.4 Temperature-measuring tube
E - Temperature-measuring instrument Sensor located on axis of D at a
distance 3d3 upstream of end of D
F 5.5 Upstream pressure-measuring tube
G - Component under test
H 5.5 Downstream pressure-measuring
tube
I - Upstream pressure gauge or
transducer
J - Differential pressure gauge or When Ap > 100 kPs (1 bar), this
transducer gauge may be replaced by a
downstream pressure gauge
or transducer
K - Flow-control valve To have a flow-rate capacity greater
than the component under test
L - Flow-rate measuring device May also be placed in position L’
upstream of D
5.3.4 All connections for pressure measurement shall be 5.6 Special requirements
arranged in such a manner that no trap can form or retain
entrained liquid ; a drain may be provided.
5.6.1 When the component under test has ports which are
not threaded~and other means of connecting to pipes or hoses
are used, measuring tubes having internal diameters which cor-
5.4 Temperature-measuring tube (item Dl
respond to the appropriate pipe or hose internal diameters shall
A tube shall be provided with an internal d i ameter, ds, which is be used.
not less than three times the internal diamete r , td , of the inlet
pressure-measuring tube (item F) and with a length not less 5.6.2 If these diameters do not correspond, measuring tubes
than ten times its internal diameter, ds. of the next largest internal diameter in the range shall be used.
5.6 Pressure-measuring tubes (items F and HI 5.6.3 When the component under test has ports which differ
in size, measuring tubes which are suited to the relevant port
shall be used.
5.5.1 Tubes which conform with figure 3 shall be provided.
Typical dimensions of the pressure-measuring tubes are also
stated in table 4.
6 Test procedures
The tube shall be straight with a smooth, circular internal sur-
face, and a constant diameter throughout its length. 5.1 Test conditions
There shall be no obstruction or branch connection other than 6.1.1 Gas supply
those specified.
6.1.1.1 The gas used shall be stated in the test report.
5.5.2 One~or more pressure-tapping holes shall be provided in
accordance with figure 3. 6.1.1.2 The~gas shall be filtered and conditioned to comply
with the recommendations of the test component manufac-
The longitudinal centreline of the tube shall intersect with the turer.
centrelines of the holes and the centrelines of the holes shall be
normal to the longitudinal centreline. 6.1.2 Checks
The junction of each hole with the internal surface of the tube Periodically check that the pressure-tapping holes are not
shall be sharp edged and free from burrs. blocked by liquids or solid particles.
4