1、C 621.892.095 : 620.1 : 543.383 : 541162.42 D EUTSC H E NO R M November 1990 DIN 51 368 Determination of fraction separated by hydrochloric acid from water mix metal working fluids Prfung von Khlschmierstoffen; Bestimmung des mit Salzsure abscheid- baren Anteils von wassergemischten Khlschmierstoffe
2、n Supersedes July 1981 edition. In keeping with current practice in standardspublished by the International Organization forStandardization (ISO), a comma has been used throughout as the decimal marker. See Explanatory notes for connection with lP137/87 published by the Institute of Petroleum (IP).
3、1 Field of application This standard deals with water mix working fluidsl) in the form of oil-in-water emulsions. 2 Scope The method described in this standard serves to determine the content of fractions separated by hydrochloric acid in water mix metal working fluids, this content being required f
4、or the assessment of oil-in-water emulsions. 3 Concept The fraction separated by hydrochloric acid is the percent- age by volume of those components which separate under the conditions specified in this standard when concentrat- ed hydrochloric acid is added. 4 Principle 100 mi of the fluid are pour
5、ed into the graduated flask (test apparatus) and concentrated hydrochloric acid is added. After allowing time for phase separation to take place, the volume of the oll-containing phase which separates is measured. 5 Designation Designation of the method of determining the fraction separated by hydro
6、chloric acid from water mix metal work- ing fluids (A): Test DIN 51 368 -A 6 Apparatus and reagents The following apparatus and reagents shall be used. 6.1 Test apparatus2) as shown in figure 1, made of colour- less and stress-free grade HBG3 glass as specified in IS0 719 not exhibiting any defects
7、likely to make it difficult to take readings. The limit of error of the test apparatus shall not exceed: a) 0,l mi for the O to 5ml range; b) 0,5 ml for the 5,5 to 30 ml range; c) 0,2 mi for the 100 mi flask capacity (up to the 30 ml mark). The test apparatus, in its working position, shall be calib
8、rat- ed with water at (20 f 0,5)“C. Note. In in the figure indicates that the test apparatus has been calibrated by pouring in. 6.2 Thermostat (e.g. water bath or oven), capable of maintaining the temperature at (95 f 3) “C. 6.3 30 to 37% technical grade hydrochloric acid, Ha. 6.4 Polyvinyl chloride
9、 fibre filter paper2). 7 Sampling Sampling shall be carried out as specified in DIN 51 750 Parts 1 and 2. Samples of used metal working fluids shall not be collected from the surface or bottom of the fluid. If possible, the samples shall be examined immediately after collection. 8 Sample preparation
10、 Filter contaminated samples before carrying out the deter- mination. Remove any oil fractions which have already separated and determine their volume under test conditions to be agreed separately. 9 Procedure Homogenize the sample at (20 i 1)“C and pour 100 ml of it into the test apparatus to the 3
11、0 ml mark. Make up to the zero mark with concentrated hydrochloric acid and stopper the apparatus. Mix the contents of the flask thoroughly by swirling repeatedly. In order to accelerate separation, place the test apparatus in the thermostat set to (95 i 3) OC. After (20 I 4) hours, remove the appar
12、atus and allow it cool to (20 f 1)OC. Bring up any oil adhering to the wall into the oil layer by detaching it with a wire loop lowered into the 1) Cf. DIN 51385 for concepts relating to metal working fluids. *) Information on suppliers can be obtained from DIN- Bezugsquellen fr normgerechte Erzeugn
13、isse im DIN Deutsches Institut fr Normung e. V., BurggrafenstraBe 6, D-1000 Berlin 30. Continued on pages 2 and 3 Beuth Verlag GmbH, Berlin. has the exclusive right of sale for German Standards (DIN-Normen). DIN 51 368 Engl. Price group 5 Sales No. 0105 05.93 Page 2 DIN 51368 Over 5 up to 30 0.5 app
14、aratus.Then read off and record thevolume ofthe upper fraction which has separated (use lower meniscus) in the graduated section of the flask. Note. It may be possible that several phases will separate as a result of the action of the hydrochloric acid, but only evaluate the upper phase (which is us
15、ually transparent). Do not include other phases in the result, but mention them in the test report. 1 10 Expression of result The result shall be given as the percentage by volume of the fraction separated by hydrochloric acid, making reference to this standard. A percentage by volume of up to 5% sh
16、all be reported to the nearest 0,l ml, and of more than 5% but not more than 30% to the nearest 0,5 ml, taking account of DIN 1333 Part 2 when rounding to the last significant place. In some cases,it may be necessaryto report the oil fraction which has separated before the test as a percentage by vo
17、lume of the total sample, to the nearest 0,1 % (cf. clause 8). 11 Precision (as specified in DIN 51 848 Part 1) The following criteria shall be used to assess the results. Repeatability (same operator, same apparatus) If two results are obtained under repeatability conditions by the same operator, b
18、oth results shall be considered accept- able and in conformity with this standard if they do not dif- fer by more than the value given in the table below. Reproducibility (different operators, different apparatus) If two separate laboratories each obtain a result under reproducibility conditions, bo
19、th results shall be considered acceptable and in conformity with this standard if they differ by no more than the value given in the table below. Table. Repeatability and reproducibility separated, as a percentage by volume by volume Up to 5 I 0,2 I 0.3 I Dimensions in mm DIN 12 242 - HNS 19/26 coni
20、cal ground glass socket Scale intervals: 0,l ml from O to 5ml 0,5 ml from 5 to 30 ml d E m O d E O e Y U c Seal test apparatus using a DIN 12 252 - C 19/26 stopper. Figure 1. Test apparatus DIN 51 368 Page 3 Standards referred to DIN 1333 Part 2 DIN 12242 Part 1 DIN 12252 DIN 51 385 DIN 51 750 Part
21、1 DIN 51 750 Part 2 DIN 51 848 Part 1 IS0 719 : 1985 IP wia7 Presentation of numerical data; rounding Laboratory glassware; interchangeable conical glass joints; dimensions and tolerances Laboratory glassware; conical ground glass stoppers Metal working fluids; terminology Sampling of petroleum prod
22、ucts; general Sampling of liquid petroleum products Testing of petroleum products; precision; general; terminology and its application to petroleum stand- ards specifying requirements Glass; water resistance of glass granules at 98OC; test methods and grading Water mix metal working oil; oil content
23、 of dilutions *) Previous editions DIN 51 368: 09.75, 07.81. Amendments The following amendments have been made to the July 1981 edition. a) The time allowed for phase separation has been extended by a factor of ten. b) The standard has been revised to take account of the specifications of DIN 1310
24、and the DIN 820 series of standardS.The references to other standards have been updated. Explanatory notes This standard has been prepared by Technical Committee 661 Prfung von Schrnierlen, sonstigen &en und Paraffinen of the FachausschuB Minerall- und Brennstoffnormung of the NormenausschuB Materia
25、lprfung (Materials Testing Standards Committee). It conforms in some respects to lP137187, but differs from the latter in specifying, instead of a flat-bottomed flask having a volume of 150 ml, a test apparatus having a more readily readable scale whose shape makes it easier for oil droplets to rise
26、. In addition, it specifies that 30 to 37% hydrochloric acid be used instead of dilute hydrochloric acid, because the former facilitates separation. The volumes of the fractions separated by hydrochloric acid are not identical to those of the emulsifiable metal working fluid in the emulsion since th
27、e latter usually contains components which are soluble in water and aqueous hydrochloric acid. In addi- tion, used metal working emulsions may be contaminated with oil which has leaked from the machine lubrication system. The information on repeatability and reproducibility is based on an interlabor
28、atory test carried out in 1987,which revealed that if40% sulfuric acid is used instead of hydrochloric acid as specified in subclause 6.3,the precision values given in the table are not complied with. International Patent Classification G O1 N 33/26 *) Obtainable from Beuth Verlag GmbH, Auslandsnormenverkauf, BurggrafenstraBe 6, D-1000 Berlin 30.
