ASTM D5800 method for evaporation loss of lubricating oils by the Noack method
Procedure B - Non-Woods Metal Apparatus
15. Introduction
15.1 The following procedure describes an automated test method that uses the same principle, and the same crucible as Procedure A. Only the heat transfer to the sample is different. It does not use Woods alloy, and the sample temperature is directly monitored.
16. Apparatus
16.1 Noack Evaporative Tester (see Fig. 6), comprising the following:
16.1.1 Heating Block Unit, electrically heated by base and jacket heaters, having a total power consumption sufficient to ensure a specimen temperature profile similar to the one recorded in the specimen when heated with the Woods metal heater block. In the center of the heating block, there is a circular recess to insert the evaporative crucible. The jacket heater is configured to ensure a direct contact with the crucible. A mechanism is provided to open the jaws for crucible insertion. Two catches on the block prevent the crucible from rising, and the base heater is spring loaded to ensure a direct contact with the crucible.
16.1.2 Evaporative Crucible, with screw cover (see Fig. 7). The crucible is made of stainless steel (see Fig. 8). Above the support ring is the thread for the cover. The nickel-plated brass cover (see Fig. 9) is hermetically sealed to the crucible by an internal conical sealing surface. Three nozzles of hardened steel (see Fig. 10) permit the air stream to pass through the cover. The extraction tube (see Figs. 11 and 12), which slopes downward, leads from a threaded and sealed connection in the center of the cover.
16.1.3 Temperature Probe - The specimen temperature measuring device shall have an accuracy of 0.5°C, or better, and a resolution of 0.1°C, or better. The probe is provided with a calibration certificate of 250.0°C with a precision of more or less 0.1°C. Its diameter is 4 mm, and its position is as indicated in Fig. 8. It should be calibrated with appropriate procedure at appropriate frequency (minimum once a year).
16.2 Balance, capable of weighing at least 500 g to the nearest 0.01 g.
16.3 Crucible Clamp and Spanner.
16.4 Reamer, 2-mm diameter.
16.5 Ball Bearing, 3 to 5-mm diameter.
16.6 Glassware Assembly, strictly identical to the description in 6.6-6.12 and 6.15 of Procedure A.
16.7 Vacuum Pump.
16.8 Central Processing Unit (CPU), capable of controlling the specimen temperature, the vacuum, the time, the heating, and the printing. The specimen is heated to 245.2 more or less 0.5°C with the temperature profile recorded in the specimen when tested with a Woods metal apparatus (1 h at 250°C) with automatic test duration compensation. The automatic test duration compensation is used because a test may be started with a heating block at room temperature or at hot temperature when several tests are carried without cooling phase. The CPU automatically adjusts the pressure differential of 20 more or less 0.2 mm. These conditions can be checked with the printed report.
16.9 Printer, to print the graphs of the specimen temperature and the vacuum recorded during the test.
17. Reagents and Materials
17.1 Cleaning Solvent - A mixture of naphtha and toluene is recommended for cleaning the crucible. (Warning - Flammable, vapor harmful.) Overnight soaking may be necessary.
17.2 Noack Reference Fluid - Oil having a known evaporative loss, the value of which is provided by the manufacturer.
17.3 Insulated Gloves.
17.4 Drying Paper.
18. Hazards
18.1 Safety Hazards - It is assumed that anyone using this test method will either be fully trained and familiar with all normal laboratory practices, or will be under the direct supervision of such a person. It is the responsibility of the operator to ensure that all local legislative and statutory requirements are met.
18.2 (Warning - Though the test method calls for a draft-free area, the exhaust fumes from the evaporating oil must be ventilated to an outside source. Precaution shall be taken to avoid any possibility of fire or explosion.) (See Note 3.)
18.3 An alternate means for preventing draft described in Appendix X3 was not used in the development of the test method precision statement.
19. Preparation of Apparatus
19.1 A standard assembly of the apparatus is shown in Fig. 6. To avoid disturbing the thermal equilibrium, the apparatus shall be assembled in a draft–free area and shall comply with Fig. 6 dimensions and apparatus. (See 18.2.)
19.2 Prepare the automated apparatus for operation in accordance with the manufacturer's instructions for calibrating, checking, and operating the equipment.
19.3 Clean the glass bottles, the glass tubing, and the Y-piece to prevent a build up of condensate.
NOTE 9 - Condensate should not be allowed to build up in the 2-L glass bottles. These should be washed out with solvent and dried before a maximum 2 cm of condensate collects.
20. Verification
20.1 Switch the instrument on a minimum of 30 min before running the test to allow temperature stabilization of measurement circuitry.
20.2 Make sure that the glassware assembly and the vacuum pump are cleaned and all the connections are sealed.
20.3 Thoroughly clean and dry all parts of the test cup and its accessories before starting the test. Check that the crucible and cover are free from lacquer. Stubborn lacquer should be removed by light abrasion with fine carborundum powder on a pad of cotton wool soaked in solvent or with a fibrous abrasive pad, followed by a rinse with solvent.
20.4 Pass the reamer through each of the three nozzles in the cover to ensure that they are clear. (Warning - Using a reamer with a diameter larger than 2 mm can enlarge the nozzles. This can lead to a wrong losses result due to increased air flow.)
20.5 Run the ball bearing through the extraction tube to ensure that it is clear of contaminants.
20.6 After the 30 min stabilization period, calibrate the temperature measuring device in accordance with the manufacturer's instructions.
20.7 Calibrate the vacuum measuring device in accordance with the manufacturer's instructions.
20.8 Weigh the empty cup without its cover to the nearest 0.01 g.
20.9 Weigh into the tared crucible 65.0 more or less 0.1 g of reference fluid to a precision of 0.01 g. This mass is called M1.
20.10 Screw on the cover using the clamp and the spanner. During this phase, make sure that the specimen will never splash on the inside part of the cover. If this occurs, even only one time, the test shall be repeated from 20.3.
20.11 Connect the specimen temperature probe to the instrument.
20.12 Press down on the locking lever located on the front of the heating block. Place the crucible in the heating block. Rotate the crucible, securing the flange under the screw heads. Adjust the final position of the extraction tube so that it is located in front of the arm of the glass Y-piece, and release the locking lever.
20.13 Connect the extraction tube to the arm of the glass Y-piece, and secure the connection with the clamp. Be sure that the stainless extraction tube, the male connection, and the right arm of the Y-piece are properly aligned.
20.14 Start the test by pressing the ON key of the CPU. In default configuration, the printer is activated. If not, refer to the instruction manual to activate the real time printing of the specimen temperature and the vacuum curves.
20.15 When the audible alarm signals the last 3 min of the test, stop the audible alarm by pressing on the OFF key. Stay in front of the equipment, and be prepared to disconnect the extraction tube.
20.16 After 60 min, the test is automatically stopped, and the end of the test alarm sounds. Remove the specimen temperature probe. Disconnect the extraction tube within 15 s maximum. Press down the locking lever. Remove the crucible. Stop the audible alarm by pressing on the OFF key.
20.17 Stand the crucible in a cold water bath to a minimum depth of 30 mm.
20.18 Check the printed report to ensure that the specimen temperature and the vacuum plotted curves stayed within the indicated limits. If one of the graph is not within the specified limits, check that the apparatus complies with the manufacturer's instruction and that the procedure has been adhered to. After these checks, rerun the test from 20.2.
20.19 After 30 min, remove the crucible from the water bath, dry the outside, and carefully remove the lid. This phase is very critical. Make sure that the sample is never in contact with the inside part of the lid.
NOTE 10 - It is very important during the manipulation of the crucible, at the start and the end of the test, to not splash the internal face of the cover with the specimen in the cup. When this occurs, it leads to higher losses and the test must be rerun.
20.20 Reweigh the crucible without the lid to the nearest 0.01 g.
20.21 Calculate the M2 mass by subtracting the empty cup mass from the mass measured in 20.19.
20.22 Calculate to the nearest 0.1 % M/M the evaporation loss of the reference fluid, using the following equation:
[(M1 - M2)/M1] x 100
where:
M1 = specimen mass before the test, and
M2 = specimen mass after the test at 245.2°C.
20.23 Compare the result obtained against the given value for the reference fluid. If the result is within limits, proceed to Section 21.
20.24 If the result is not within the limits, check that the apparatus complies with the manufacturer's instruction and that the procedure has been adhered to.
20.25 Recheck the evaporation loss of the reference oil. To do so, proceed as described in 20.2.
21. Procedure
21.1 Weigh into a tared crucible 65 more or less 0.1 g representative of test specimen to a precision of 0.01 g.
NOTE 11 - Sample in accordance with Practice D4057 or Practice D4177.
21.2 Proceed as described in 20.3-20.20.
21.3 Calculate to the nearest 0.1 % M/M the evaporation loss of the specimen, using Eq 4.
22. Calculation
22.1 Evaporation loss is obtained from the difference in weight before and after test. The specimen is heated in accordance with the temperature profile recorded in the specimen when tested with a Woods metal apparatus (1 h at 250°C) with automatic test duration compensation. The automatic test duration compensation is used because a test may be started with a heating block at room temperature or at hot temperature when several tests are carried without cooling phase. The checking of these conditions can be done with the printed report. Calculate evaporation loss, using the following equation:
[(M1 - M2)/M1] x 100
where:
M1 = B - A,
M2 = C - A,
A = empty crucible weight,
B = crucible plus specimen weight, and
C = crucible plus specimen after the test.
22.2 Some consistent differences in results determined using Procedures A and B have been observed depending on the type of sample tested. A test result obtained using one of the procedures can be transformed to an estimated result on the basis of the other procedure as follows:
22.2.1 Formulated Engine Oils - The following relationships are based on the round robin test results on formulated engine oils with volatilities in the range of 10.5 to 21.5 % Noack:
Value by Noack Procedure B = 1.030 x Value by Noack Procedure A
Value by Noack Procedure A = 0.970 x Value by Noack Procedure B
The 95 % confidence limits for the regression coefficient in Eq 6 are 1.021 to 1.033; those for the coefficient in Eq 7 are 0.968 to 0.980.
22.2.2 The following relationships are based on round robin test results on basestocks with volatilities in the range of 4 to 25 % Noack:
Value by Noack Procedure B = 0.962 x Value by Noack Procedure A
Value by Noack Procedure A = 1.039 x Value by Noack Procedure B
The 95 % confidence limits for the regression coefficient in Eq 8 are 0.950 to 0.959; those for the coefficient in Eq 9 are 1.043 to 1.053.
NOTE 12 - The results of Noack residue should not be rounded up before using the multiplication factors given in Eq 6-9.
23. Report
23.1 Report the following information:
23.1.1 The nearest 0.1 % M/M as evaporation loss (Test Method D5800, Procedure B).
23.2 Conversion of values from either D5800 A or D5800 B to the other:
23.2.1 Only if the nature of the test specimen is known with certainty, in other words, it is known to be either a basestock or a formulated engine oil, the evaporation loss calculated in 22.2.1 on the basis of either Procedure A or Procedure B may be converted to an equivalent result on the basis of the other procedure. The appropriate equation from those above should be selected and applied according to the type of the sample tested (formulated engine oil or basestock).
23.3 Report the converted result from Procedure A to B, or Procedure B to A to the nearest 0.1 m % as evaporation loss of the test sample as converted from the original procedure to the calculated basis procedure.
23.4 If the nature of the test specimen is not known as being either a basestock or a formulated engine oil, then the results of the test using D5800 B must be identified as being run under D5800 B and the value of percent evaporation so obtained will require additional information on the nature of the test specimen for calculations to be made to generate the standard value produced by D5800 A.
23.4.1 Converted results should be reported as D5800 A (converted from the results obtained by D5800 B) or as D5800 B (converted from the results obtained by D5800 A).
24. Precision and Bias
NOTE 13 - Equipment available from ISL, BP 40, 14790 VERSON-France was used to develop the precision statement for Procedure B.
24.1 To estimate the precision of Procedure B, the test results from the interlaboratory study were analyzed following Practice D6300.
24.2 The interlaboratory study included eight oils, two base oils, and six finished oils, tested in twelve laboratories.
24.3 The precision of this test method, as determined by the statistical examination of the interlaboratory study test results, is as follows:
24.3.1 Repeatability - The difference between two tests results obtained by same operator with the same apparatus under constant operating conditions on identical test materials would, in the long run, exceed the following value in only one case in twenty.
Repeatability = 0.095X(0.5)
where:
X = average of the two determinations under consideration.
24.3.2 Reproducibility - The difference between two single and independent results obtained by different operators working in different laboratories on identical test materials would, in the long run, exceed the following value in only one case in twenty.
Reproducibility = 0.26X(0.5)
where:
X = average of the two determinations under consideration.
24.4 Bias - Since there is no accepted reference suitable for determining the bias for this procedure, no statement on bias is being made.
