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UDC 637.1/3
IS0
I NT ERN AT I ON AL O RG A N IZAT I O N FOR STAND AR D I2 AT I O N
IS0 RECOMMENDATION
R 488
BUTYROMETERS FOR THE DETERMINATION
OF THE PERCENTAGE OF FAT IN MILK BY THE GERBER METHOD
1st EDITION
July 1966
COPYRIGHT RESERVED
The copyright of IS0 Recommendations and IS0 Standards
belongs to IS0 Member Bodies. Reproduction of these
documents, in any country, may be authorized therefore only
by the national standards organization of that country, being
a member of ISO.
For each individual country the only valid standard is the national standard of that country.
Printed in Switzerland
Also issued in French and Russian. Copies to be obtained through the national standards organizations.
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BRIEF HISTORY
The IS0 Recommendation R 488, Butyrometers for the Determination of the Percentage
of Fat in Milk by the Gerber Method, was drawn up by Technical Committee ISO/TC 90,
Apparatus for Testing Milk and Milk Products, the Secretariat of which is held by the
Deutscher Normenausschuss (DNA).
Work on this question by the Technical Committee began in 1959 and led, in 1963,
to the adoption of a Draft IS0 Recommendation.
In March 1964, this Draft IS0 Recommendation (No. 700) was circulated to all the
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IS0 Member Bodies for enquiry. It was approved, subject to a few modifications of an
editorial nature, by the following Member Bodies :
Austria Greece New Zealand
Belgium India Portugal
Brazil Ireland Sweden
Chile Israel Switzerland
Colombia Japan Turkey
United Kingdom
France Korea, Rep. of
Germany Netherlands U.S.A.
No Member Body opposed the approval of the Draft.
The Draft IS0 Recommendation was then submitted by correspondence to the IS0
Council, which decided, in July 1966, to accept it as an IS0 RECOMMENDATION.
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IS0 / R 488 - 1966 (E)
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IS0 Recommendation R 488 July 1966
BUTYROMETERS FOR THE DETERMINATION
OF THE PERCENTAGE OF FAT IN MILK BY THE GERBER METHOD
1. SCOPE
This IS0 Recommendation specifies the characteristics of butyrometers for the determination
of the percentage of fat in milk by the Gerber method and also those of the stoppers.
2. TYPES OF BUTYROMETERS
Six types of butyrometers are specified as follows:
O to 4% butyrometer for testing milk
Oto 5% 9, 9, $9 9,
99 9,
Oto 6% $9 99
9, 3.
Oto 7% 3- 99
3, 9,
Otû 8% 9’ 3,
O to 10% ” 79 Y> ,,
3. DETAILS OF CONSTRUCïiON
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(See Fig. 1, page 6)
3.1 Dimensions
The butyrometers should conform to the dimensions shown in Table 1.
TABLE 1. - Dimensions of the butyrometers
Dimensions Miilimeîres
Overall length 190 f5
Internal diameter of neck 11 f0.5
Length of neck 14.5 -+ 1.5
Maximum external diameter of body 25
Maximum external diameter of bulb 15
Minimum wall thickness (1) 0.9
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(I) The wall thickness throughout should be adequate to render the butyrometer sufficiently
robust for the purpose for which it is intended.
3.2 Material
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The butyrometers should be made from clear glass which should be resistant to thermal
shocks and chemicals * inherent in the method and should be as free as possible from
visible defects.
3.3 Neck
Two types of necks are permitted on the butyrometers:
3.3.1 Plain neck, preferably thickened by an outside rim at the top to a maximum of 2.5 mm
1, page 6);
(see Fig.
3.3.2 Corrugated neck (see Fig. 2, page 6). In this type, the corrugations should be in planes
at right angles to the axis of the butyrometer and not form a spiral producing a screw
thread; the internal diameter of the neck (see Table 1 above) should be measured at the
narrow parts of the corrugations. The number of corrugations is not specified.
* The chemical resistance characteristics should conform to the IS0 Recommendations drawn up by Technical Committee
ISO/TC 48. Laboratory Glassware and Related Apparatus.
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IS0 / R 488 - 1966 (E)
3.4 Body
The capacity of the butyrometers between the base of the neck and the O % graduation mark
(i.e. between levels A and B in Fig. 1 below) should be as shown for the appropriate butyro-
meter in Table 2, page 7.
3.5 Graduated tube
The graduated tube of the six types of butyrometers for testing milk should be of the flat-
scale type shown in cross-section in Fig. 1 below; the back surface of the tube should not
be frosted.
Butyrometers for testing milk
(Dimensions in accordance with Table 1, page 5, and Table 2, page 7)
External diameter
Dimensions in millimetres
secfion X-
...