Tiêu chuẩn iso 01768 1975 scan

INTERNATIONAL STANDARD I NTERNATIONAL ORGANIZATION FOR STANDARDIZATION M%K~YH uO~HAI I OPrAHH3AUMR n0 CTAH~APTM3AUMM~ORGANISATION INTERNATIONALE DE NORMALISATION Glass hydrometers Conventional value f[.]

INT RATIO AL O G NIZATIO FO STADR IZATIO M% K ~Y H.uO~H I OPrA HH3A UMR n0 CTA H~A PTM3A UM ~OR A NISA TION INT R A TIONA LE DENORMA LISA TION

A rbomBtres envere - V aleur c nv entio nele po r la diata bi te v lumiq e thermiq e (c i uti ser lors de

I’e’ta l s ement des ta bles de mes rage des l q ides)

F irst e itio - 19 5-0 -01

UDC 5 2.3 : 5 1.7 4.3 : 5 0 1.7

Desriptors : la bora tory gla sswa re, h rometers, thermal expa nsion

IS0 (h Intern tio al Org nizatio for Sta d rdizatio ) is a w orldw id fe eratio

of n tio al sta d rds institutes (IS0 Memb r Bo ies) Th work of d v lo in

Intern tio al Sta d rds is carie out throug IS0 Tech ical Com ite s Ev ry

Memb r Bo y intereste in a s bject for w hich a Tech ical Com ite h s b e set

up h s th rig t to b re rese te o th t Com ite Intern tio al org nizatio s,

g v rnme tal a d n n-g v rnme tal in laiso with ISO, also tak e p rt in th w ork

Draf Intern tio al Sta d rds a o te by th Tech ical Com ite s are circ late

to th Memb r Bo ies for a pro al b fore th ir ac e ta ce as Intern tio al

Sta d rds by th IS0 Counci

Prior to 19 2, th res lts of th work of th Tech ical Commite s were publsh d

as IS0 Recom e d tio s; th se d c me ts are n w in th proces of b in

tra sforme into Intern tio al Sta d rds As p rt of this proces , Tech ical

tech icaly s ita le for tra sformatio Intern tio al Sta d rd IS0 17 8 th refore

re laces IS0 Recom e d tio R 17 8-19 0 to w hich it is tech icaly id ntical

folow in countries :

Ca a a

Irela d

Czech slo a ia

Ita ly

South A frica, Re of

Sp in

Th ia d

Turk y

U.S.A

Y ug sla ia

No Memb r Bo y expres e disa pro al of th Recomme d tio

Intern tio al Sta d rd

0 Interna tional Organization for Stan ardization, 195 l

Gla ss hydrometers - Conv entiona l v a lue for the therma l

1 SC P A D FIELD O F A PPLICA T IO N

This Interna tio a l Sta nda rd sp cifies, for u e in th

p re a ra tio

of mea sureme t ta bles for lquids, a

co v entio a l v a lue for th th rma l c bic expa nsio

c oeficie t of gla ss hydrometers It sta tes h w th

in ica tio s of hydrometers ha v in a ‘th rma l c bic

co v entio a l v a lue may b corecte for u e in co n ctio

with me s reme t ta bles-in th co stru tio of which th

co v entio a l v a lue h s b e u e

2 APPLICABILIT Y O F CO EF ICIE T

Me s reme t ta bles for lquids prov id me ns for d riv in ,

from th in ica tio s of d nsity a nd/ or rela tive d nsity

hydrometers a t v a riou temp ra tures, th coresp n in

v a lue of th d nsity a nd/ or rela tiv e d nsity with resp ct to

wa ter of th lquid a t a refere ce temp ra ture In princip le

s ch mea sureme t ta bles mu t ta ke a ccount of th th rma l

exp nsio of th hydrometers Since hydrometers a re ma e

of v a riou gla sses, th ir expa nsio co ficie ts difer

Co se ue tly, it is d sira ble to u e a sin le, co v entio a l

th rma l c bic expa nsio co ficie t in th co stru tio of

mea sureme t ta bles a d to a ssocia te with th ta bles

inform io o h w to a dju t a ppro ria tely to th ta bles

th in ic a tio of a hydrometer ha v in a y oth r th rma l

c bic expa nsio c oeficie t

3 C N E TIO NA L VA LU O F CO EF ICIE T

It is recom e d d tha t whe pre a rin mea sureme t ta bles

for lquids th th rma l c bic expa nsio co ficie t of gla ss

hydrometers sh uld b taken to b 0,0 0 0 5/C

4 INDICA TIO N O F CO EF ICIE T U ED

4.1 The th rma l c bic expa nsio co ficie t of th

co stru tio of me s reme t ta bles for lquids sha ll b

sta te in th ta bles

4.2 It sha ll b in ica te in th mea sureme t ta bles tha t

hydrometer rea din s may ha ve to b mo ifie pre a ra tory

to u in th ta bles if th th rma l c bic expa nsio

0,0 0 0 5/ “C

EX PA NSION CO EF ICIE T

0,0 0 0 5/k

5.1 Ge era l

T he rela tio ship b twe n

A SSO CIA T ION WIT

a ) th in ica tio (R ) a t 0 “C of a hydrometer of which

th sta nda rd temp ra ture is t “C a d th th rma l expa n-

sio is e ua l to th co v entio a l v a lue 0,0 0 0 5PC, a nd

b) th in ica tio (I?‘) a t 6 “C of a hydrometer ha v in

th th rma l expa nsio y/O C, but oth rwise simia r,

is giv en by

R=R’[1+(0,0 0 2 -$(8- ]

Co se ue tly, b fore u in mea sureme t ta bles in th

co stru tio of which th co ficie t 0,0 0 0 5 C h s

b e u e , th hydrometer in ica tio R’ a t 0 “C sha ll b

mo ifie to

R’ [ 1 + (0,0 0 0 5 - y) (0 - t]

It is a ppa re t tha t R’ may b mo ifie eith r by

multiply in it by

1 + (0,0 0 0 5 -7) (0 - t

or by a ddin to it

R’ (0,0 0 0 5 - y) (0 - t

5.2 Ap plca b ilty to d nsity hydrometers

Ass min tha t t ‘C is 2 °C, th prefere sta nda rd

ISO /R 6 9, De sity hydrometers for g n ra l purp ses, R’

may b mo ifie eith r by multiplyin it by

1 + (0,0 0 0 5 - 7) (6 - 2 )

or by a ddin to it

R’ (0,0 0 0 5 - y) (0 - 2 )

If t “C is 15 “C or 2 ‘C, th oth r recom e d d sta nda rd

temp ra tures, th se v a lues sha ll b s bstitute for 2 “C

TA BL 1

V a lues of R’ (0,0 0 -7 ) (0 - t ) when (0 - r l = 1

Unit : 0,01 g/ml

V a lue of (0,00 05 -7)

R’

0,00 010 0,00 015

0,00 00

0,012

0,014

0,016

0,018

0,00

0,0

1.2

0,0

5.3

Ap plc a b ilty to rela tiv e d nsity 6 /6 “F hydrometers

Wh n rela tive d nsity 6 /6O ”F hydrometers a re u e , it is

u ua l to expres th temp ra ture of th lquid in d gre s

F a hre h it T he mo ifica tio formula quote in 5.1 th n

b comes

R '[l + (0,0 0 0 5-y); (0 -6 1

wh re ti O F is th temp ra ture of th lquid a nd y sti

re rese ts th expa nsio p r d gre Celsiu

It folows tha t R’ may b mo ifie eith r by multiplyin it

by

1 + (0,0 0 0 5-y): (8 - 6 )

or by a ddin to it

R ' (0,0 0 0 5-y) $ -6 )

TA BL 2

V a lues of R’ (0,00 05 - y) 5 (0 - 6) when

(8 - 6) = 1 a nd 0 is exp resed in degres F a hren eit

Unit : 0,01 r elativ e denity

R’

0.6

0.7

‘3

0

1.0

1.1

1.2

V alue of (0,0 05 -

7 )

0,00 010 0,00 015

0,00 00

0,0 8

0,010

0,Ol

0.012

0.013