SCIENTIFIC SECTOR CATALOGUE - Flipbook - Page 25
Hydrometers
The traditional hydrometry scale of speci昀椀c
gravity (density, relative to that of water at
60°F) used in the 1960 edition of the British
Standard 718 is still much in demand and
the general purpose hydrometers at the
beginning of this catalogue section use this
scale.
Instruments adjusted at this higher temperature can be supplied to special order. In addition to
being adjusted for use at a speci昀椀c reference temperature, hydrometers are adjusted with regard
to the surface tension of the materials whose density is to be determined. Surface tension may be
expressed speci昀椀cally for example 55 mN/m (millinewtons per metre) or described as a band.
Low surface tension is less than 35 mN/m and medium surface tension is between 35 and 55 mN/m.
Hydrometers
For the speci昀椀cation density hydrometers to
BS 718 : 1991, the internationally accepted
basis of scale is grams per millilitre (g/ml)
with a reference temperature of 20°C (or,
exceptionally 15°C). For use in tropical
countries, ISO 387 proposes that hydrometers
be adjusted at a higher reference temperature, 27°C (as opposed to the previously used high
adjustment of 84°F).
All hydrometers can be supplied with UKAS
(0582) certi昀椀cation*, certi昀椀cate traceable
to recognised national standard or
statement of conformity, if required.
EX
AM
P
LE
* UKAS calibration carried out via a third party laboratory.
Measurement for life.
Hydrometer cylinders
Hydrometer jars are available with a standard internal
diameter of 37mm.
Internal
depth
Suitable for
hydrometer series
Product
number
200mm
S50
10/000/0
300mm
M50 & M100
10/000/1
330mm
L50
10/000/2
brannan.co.uk
sales@brannan.co.uk
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