ASTM D7109 Standard Test Method for Shear Stability of Polymer Containing Fluids Using a European Diesel Injector Apparatus at 30 and 90 Cycles
9. Sampling
9.1 Approximately 650 mL of fluid is needed per test.

9.2 The test fluid shall be at room temperature, uniform in appearance, and free of any visible insoluble material prior to placing it in the test equipment.

9.3 Water and insolubles shall be removed before testing, or filter blocking and nozzle wear may occur. Filter blocking can be detected by a sudden change in gauge pressure. The transport of insolubles to the shear zone will shorten nozzle life.

10. Calibration and Standardization
10.1 Nozzle Adjustments - If the nozzle to be used is new or has not been pre-calibrated, adjust the diesel injector nozzle holder with the nozzle in place. Adjust the nozzle using diesel fuel and a nozzle tester so that the valve opening pressure is 13.0 MPa (1885 psi) under static conditions. If the nozzle has been pre-calibrated with RL233 calibration oil, adjust the valve opening pressure to the calibration pressure prescribed, which must be between 13.0 MPa (1885 psi) and 18.0 MPa (2611 psi).
10.1.1 Install the nozzle and the nozzle holder in the test apparatus. The pintle/spray nozzle shall be tightly fitted in the chamber to avoid leakage of oil around the external surface of the spray nozzle.

10.2 Measurement of Residual Undrained Volume, Vres:
10.2.1 The residual undrained oil volume of the system is the volume of the system between the three-way stopcock below the fluid reservoir (8) in Fig. 1, and the injector nozzle orifice (1). V res does not include the atomization chamber volume. When the residual undrained volume is known, go to 10.3.

10.2.2 To determine residual undrained volume, first remove as much fluid as possible by briefly running the pump.

10.2.3 Remove the high-pressure lines (16) in Fig. 1, and drain. Remove the plug at the end of the pump gallery to drain the remaining oil in the pump. Drain atomization chamber (2).

10.2.4 Reassemble the system and close all drains. The upper three-way stopcock (6) shall be open to the lower reservoir (7) and the lower three-way cock (8) shall be open to the pump suction (10).

10.2.5 Add 170 mL of RL233 calibration oil to the lower reservoir (7) and observe the level. Start the pump and run for several minutes until the oil is transparent and free of suspended air.

10.2.6 Stop the pump. Drain the fluid in the atomization chamber into a beaker and then pour the fluid back into the lower reservoir; draining to waste will result in an error in the measurement of Vres. Allow the system to drain for 20 min and free air trapped in the transparent connecting tube between the lower reservoir and pump.

10.2.7 Observe the difference in oil level in the lower reservoir compared to that noted in 10.2.5. Record this difference as the residual volume, Vres.

NOTE 11 - Undrained residual volumes of 15 to 30 mL have been reported by various users of this test. V res measurements in excess of this may occur when fluid in the atomization chamber is not poured back into the lower reservoir as in 10.2.6, or if the length of line (10) is excessive.

10.2.8 Calculate the run volume, Vrun, which is the difference between 170 mL and Vres, Vrun = 170 - Vres.

10.3 Cleaning the Apparatus, Setting the Stroke Counter, and Adjusting the Pump Stroke:
10.3.1 Drain residual oil by way of drain line (17) from the atomization chamber into a waste container. Drain fluid in the cooling jacket by means of stopcock (6) (Fig. 1) and the fluid reservoir by means of stopcock (8), into suitable waste containers.

10.3.2 After fluid has drained, leave the stopcock on the drain line to the atomization chamber open and the three-way stopcock (6) positioned so that fluid in the cooling jacket drains to a waste container. Position stopcock (8) so that the drain is closed but the fluid reservoir is open to pump suction through line (10). Add a minimum of 50 mL of RL233 to the fluid reservoir.

NOTE 12 - Steps 10.3.2 to 10.3.7 are representative of the first and second purges with 50 mL fluid that are needed to remove used oil from the apparatus prior to calibration and testing. For these steps, the stopcock below the atomization chamber and cooling jackets are set so that oil will flow into waste containers.

10.3.3 Free the apparatus of air in the line by use of the venting screw (14), and by manual compression of the transparent flexible tube that connects the pump to the fluid reservoir.

10.3.4 Set the stroke counter so that the pump will run a sufficient length of time to evacuate the fluid out of the fluid reservoir.

10.3.5 Start the pump. Observe the fluid level in the reservoir and stop the pump when all the fluid is out of the base of the reservoir but is still fully-retained in line (10).

10.3.6 Add a minimum of 50 mL of RL233 fluid to the fluid reservoir a second time and operate the pump until the fluid reservoir is empty but line (10) is still filled with fluid.

10.3.7 After all oil has drained, close the stopcock on the atomization chamber drain line (17), position stopcock (6) so that fluid will flow from the cooling jacket into the fluid reservoir.

10.3.8 Remove the thermometer or temperature probe from the fluid reservoir.

NOTE 13 - The thermometer and assembly can interfere with the obtainment of accurate volume measurements in the fluid reservoir, hence its removal is called for when the accurate determination of fluid volume is needed. A thermocouple or thermistor probe is a suitable alternative to a thermometer.

10.3.9 Add a minimum amount of fluid equal to the sum of 30 mL plus Vrun, determined in 10.2.8, to the fluid reservoir.

10.3.10 Close the stopcock below the atomization chamber drain line (17) and position stopcock (6) so that the fluid will drain from the cooling jacket into the fluid reservoir.

NOTE 14 - The atomization chamber drain line is always closed for the third cleaning run and all test runs.

10.3.11 Free the apparatus of air in the line by manual compression of the flexible tube (10) that connects the pump to the fluid reservoir. The venting screw (14), is also used for this purpose.

10.3.12 Record the number on the stroke counter.

10.3.13 Use a stopwatch or other timing device and run the pump for 1 min +/- 1 s.

10.3.14 Determine n, the difference in the stroke count from 10.3.12. n is the number of strokes per minute.

10.3.15 Set the stroke counter shutoff to the product of three times n. The pump shall run for 3 min +/- 3 s. Obtain a timing device to observe the time the stroke counter is on to ensure n is correct. Start the pump and allow oil to circulate until the impulse counter shuts down the instrument.

10.3.16 When all fluid has drained, adjust the volume of oil in the fluid reservoir so that the volume is equal to Vrun.

10.3.17 Set the impulse counter to 0.5 (n).

10.3.18 Close stopcock (6) so that fluid will be stored in the cooling jacket after the pump is started.

10.3.19 Start the pump. When the pump stops and draining is complete, subtract the volume now in the fluid reservoir from Vrun.

10.3.20 If the difference is within +/- 2.5 mL of one half of the total volume (Vtot = Vrun + Vres), proceed to 10.4.

10.3.21 When the volume in the fluid reservoir is not within +/- 2.5 mL of V tot , drain the fluid from the cooling jacket back into the fluid reservoir, adjust the pump stroke by means of the pump adjustment screw (12), and repeat steps beginning with 10.3.16.

10.4 Warm-up - A half-hour warm-up period is required before proceeding to calibrate with RL233. Set the stroke counter shut-off to 30 times n strokes, and start the pump.

NOTE 15 - This warm-up period is only required for the first within-day calibration.

10.5 Removal of Fluid - Open the stopcock below the atomization chamber and drain to waste. Drain the fluid from the cooling jacket into a waste container. Position stopcock (8) so that all fluid in the fluid reservoir is removed to a waste container. When drainage is complete, position stopcock (8) so that the drain is closed and the pump inlet line (10) is open.

10.6 Calibration with RL233:
10.6.1 Ensure that the ambient (room) temperature is between 20 and 25°C.

10.6.2 Add a minimum of 50 mL of RL233 to the fluid reservoir. Position the three-way stopcock, (6) in Fig. 1, below the cooling vessel to discharge fluid into a suitable waste container and leave the stopcock open below the atomization chamber. Operate the pump until the fluid reservoir is empty but line (10) is still filled with fluid.

10.6.3 Free the apparatus of air in the line by manual compression of the flexible tube that connects the pump to the fluid reservoir. When necessary, venting screw (14) is also used for this purpose.

10.6.4 Add a minimum of 50 mL of test fluid to the fluid reservoir a second time and operate the pump until the fluid reservoir is empty again but line (10) is full.

10.6.5 Close the stopcock below the atomization chamber, position the stopcock below the fluid reservoir so that the line to the pump is open, and retain the position of the stopcock below the cooling jacket so that the first 50 mL of RL233 can be drained into a waste container.

10.6.6 Place a volume of RL233 in the fluid reservoir equal to Vrun plus 30 mL.

10.6.7 Start the pump, and stop the pump when there is a 50 mL drop of fluid in the fluid reservoir. After draining is complete, reposition the stopcock below the cooling jacket so subsequent fluid flows directly into the fluid reservoir.

10.6.8 Set the stroke counter for automatic shutoff at the required number of impulses (30 multiplied by n impulses per minute). The flow rate will be 170 mL/min as set in 10.3.

10.6.9 Adjust, if necessary, the volume of fluid in the fluid reservoir to Vrun.

10.6.10 Place the temperature measuring device in the fluid reservoir, and start the pump.

10.6.11 After about 10 min of operation, adjust the water flow to control the fluid temperature at 30 to 35°C, as measured at the discharge point of the fluid reservoir. Approximately 10 min of operation will be required before the temperature can be stabilized.

10.6.12 At approximately ten cycles of operation, record the gauge pressure reading to the nearest 0.1 MPa (15 psi), when a glycerol-filled pressure gauge is being used, or to 0.01 MPa (1.5 psi), when an electronic pressure device is employed.
10.6.12.1 The pressure measurement device must occasionally be pressure tested to ensure accuracy.

10.6.13 After 30 cycles has elapsed and the pump has stopped, open the stopcock below the atomization chamber and drain fluid into a waste container. Open the three-way stopcock below the fluid reservoir and discharge the first 10 to 15 mL as waste in order to flush out the drain line. Discharge the remaining fluid into a clean sample container. After the fluid has drained, close the three-way stopcock.

10.6.14 Remove the thermometer or temperature probe.

10.6.15 Using Test Method D445, determine the kinematic viscosity at 100°C of unsheared (untested) RL233, as well as the sheared fluid from 10.6.13. Use the same viscometer tube for the measurement of each oil.

10.6.16 Calculate viscosity loss (VL) as follows:
VL = Vu - Vs
where:
Vu = kinematic viscosity of unsheared oil at 100°C, mm2/s, and
Vs = kinematic viscosity of sheared oil at 100°C, mm2/s.

10.6.17 VL for RL233 shall be within the range of 2.7 to 2.9 mm2/s at 100°C at a gauge pressure reading between 13.0 and 18.0 MPa, as recorded after 10 min of test time. If this is achieved, the gauge pressure recorded in 10.6.12 will subsequently be referred to as the calibration pressure.

10.6.18 If VL is less than 2.7 mm2/s, increase the gauge pressure. If VL is greater than 2.9 mm2/s, reduce the gauge pressure, provided that the gauge pressure recorded in 10.6.12 is greater than 13.0 MPa and less than 18.0 MPa. To alter the pressure, remove the dust cover of the spray nozzle holder (see Fig. 4), loosen the locking nut, and turn the adjustment screw that regulates valve opening pressure. Then, tighten the locking nut and replace the dust cover. The nozzle and nozzle holder need not be removed from the apparatus. Upon retesting RL233 the values shall be within the tighter range of 2.75 to 2.85 mm2/s at 100°C at a gauge pressure reading between 13.0 and 18.0 MPa, as recorded after 10 min of test time.

NOTE 16 - It is extremely important that the locking nut be completely tightened. When it is not, some leakage of fluid around the outside of the nozzle assembly may occur. This may result in a reduction of mechanical shearing for some oils, which can adversely influence precision. This condition can be monitored by use of a recorder and an electronic pressure measurement device. Leakage results in a sudden drop in pressure when fluid by-passes the nozzle orifice.

10.6.19 When VL is greater than 2.85 mm2/s at a gauge pressure of only 13.0 MPa, pre-condition the nozzle by substitution of a fully-formulated engine lubricant as the test fluid. The stroke counter shut-off shall be adjusted so that the test time is at least 8 h, instead of 30 min. Upon retesting RL233 the values shall be within the tighter range of 2.75 to 2.85 mm2/s at 100°C at a gauge pressure reading between 13.0 and 18.0 MPa, as recorded after 10 min of test time.

NOTE 17 - Suitable break-in oils include, but are not limited to, fully-formulated SAE 15W-40 heavy-duty engine lubricants.

10.6.20 When viscosity decrease is below 2.75 mm2/s at a gauge pressure of 18.0 MPa, another nozzle shall be installed and the calibration procedure shall be repeated.

NOTE 18 - Before calibration with a new nozzle, it is advisable to subject the nozzle to at least a 4 h run-in with break-in oil.

10.7 Calibration Period:
10.7.1 Calibration with RL233 Fluid - Frequent testing of the apparatus with the calibration oil is recommended. The apparatus shall be recalibrated after 540 cycles.

10.7.2 Calibration with RL233 and Monitoring System Stability and Precision with a Quality Control Oil per Practice D6299 - A quality control oil can be used to monitor calibration once the nozzle has been calibrated with RL233 fluid. This quality control fluid shall have a new oil kinematic viscosity at 100°C of between 14.0 and 17.0 mm2/s and after test kinematic viscosity decrease at 100°C ofbetween 2.0 and 3.0 mm2/s. The base oil for this fluid shall have a kinematic viscosity of between 4.0 and 8.0 mm2/s at 100°C. The calibration procedure is as follows:
10.7.2.1 Calibrate with RL233.

10.7.2.2 Monitor stability and precision of the system through QC sample testing per Practice D6299, paragraph 7.1. This will initially require 15 control samples to develop a control chart.

10.7.2.3 The quality control oil shall be run on the same day that a test fluid is evaluated.

10.7.2.4 Any deviation or trend indicated in the control chart shall call for a recheck with RL233 fluid. A recheck with RL233 shall be done after seven days even if no recheck has been required.

NOTE 19 - Calibration of the apparatus for this test method is identical to that for Test Method D6278, and is valid for either method.