ASTM D7109 Standard Test Method for Shear Stability of Polymer Containing Fluids Using a European Diesel Injector Apparatus at 30 and 90 Cycles
11. Procedure
11.1 Flow Rate Adjustment for Test Oil - Open the stopcock on the atomization chamber and drain any previous fluid out of the chamber. Position the three-way stopcock ((6) in Fig. 1) below the cooling jacket to discharge fluid into a suitable waste container. Then, position stopcock (8) so that the drain line is closed but line (10) is open from the fluid reservoir to the pump.
11.1.1 Add a minimum of 50 mL of test fluid to the fluid reservoir.
11.1.2 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, the venting screw (14) is also used for this purpose.
11.1.3 Operate the pump until the fluid reservoir is empty but line (10) is full.
11.1.4 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 still full.
11.1.5 After draining is complete, close the stopcock on the atomization chamber and position stopcock (6) so that fluid will flow from the cooling jacket into the fluid reservoir.
11.1.6 Add an amount of test fluid to the fluid reservoir equal to the sum of 30 mL plus Vrun.
11.1.7 Free the apparatus of air in the line by use of the venting screw (14) and by manual compression of the flexible tube that connects the pump to the fluid reservoir.
11.1.8 Set the stroke counter to the product of three times n, and start the pump and allow oil to circulate until the impulse counter shuts down the instrument.
11.1.9 Adjust the oil level in the fluid reservoir to Vrun by draining any excess oil to a waste container, or adding oil when needed.
11.1.10 Set the impulse counter to the product of 0.5 times n.
11.1.11 Close stopcock (6) so that fluid will be stored in the cooling jacket after the pump is started.
11.1.12 Start the pump. When the pump stops, subtract the volume now in the fluid reservoir (7) from Vrun.
11.1.13 If the difference is within +/- 2.5 mL of one-half of the total volume, (Vtot = Vrun + Vres), proceed to 11.1.15.
11.1.14 When the volume in the fluid reservoir is not within +/- 2.5 mL one-half Vtot, adjust the pump stroke slightly by means of the pump adjustment screw (12), drain the fluid from the cooling jacket into the fluid reservoir, and repeat steps beginning with 11.1.6.
11.1.15 Calculate n 1 , the number of pulses strokes required to circulate 200 mL of test oil once (one cycle) for 1 min. by the following equation:
n1 = [(170 + 30)/170]·n = 1.176n
where:
n = number of strokes required to circulate 170 mL for 1 min., as determined in 10.3.14.
11.2 Removal of Fluid - Leave stopcock below atomization chamber closed. Drain the fluid from the cooling jacket into a waste container, then reposition the stopcock so that the fluid will flow into the fluid reservoir. Then open the three-way stopcock below the fluid reservoir to discharge fluid into a waste container.
11.2.1 Test Oil Evaluation - Reposition stopcock (8) so that line (10) is open. Leave the stopcock below the atomization chamber closed. Reposition stopcock (6) below the cooling jacket so that the first 50 mL of test oil is sent to a waste container.
11.2.2 Place a volume of test oil in the fluid reservoir equal to Vrun plus 60 mL. The total volume should be approximately 200 mL.
11.2.3 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, the venting screw (14) is also used for this purpose.
11.2.4 Start the pump, and stop the pump when there is a 50 mL drop of fluid in the fluid reservoir. When draining is complete, reposition the stopcock below the cooling jacket so subsequent fluid flows directly into the fluid reservoir.
11.2.5 Set the stroke counter for automatic shutoff at the required number of impulses (30 multiplied by n1). This will correct for the additional volume to attain a 30 cycle intermediate result.
11.2.6 When necessary, adjust the volume in the fluid reservoir to (Vrun + 30) mL.
11.2.7 Insert the thermometer assembly or temperature probe in the fluid reservoir.
11.2.8 Start the pump for the 30 cycle phase of shearing.
11.2.9 Within the first 10 min, adjust the water flow to control the fluid temperature at 30 to 35°C, as measured at the discharge point of the fluid reservoir.
NOTE 20 - It is not necessary to record the gauge pressure reading here, which may differ from the previously recorded calibration pressure.
11.2.10 After 30 cycles have elapsed and the pump has stopped, 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. Remove the thermometer assembly or probe from the fluid in the reservoir to obtain an accurate volume measurement (hold above fluid for 1 min to allow drainage into the reservoir). Discharge 15 to 20 mL of the remaining fluid into a clean sample container until the reservoir has Vrun mL remaining. This is the 30-cycle sheared sample. Save the 30-cycle sheared sample for further testing.
11.2.11 Replace the thermometer assembly or probe in the fluid reservoir.
11.2.12 Set the stroke counter for automatic shutoff at the required number of pulses (60 times n) to achieve a total of 90 cycles on the remaining material.
11.2.13 Restart the pump for the remaining 60 cycles of the 90 cycle test.
11.2.14 Within the first 10 min, adjust the water flow to control the fluid temperature at 30 to 35°C, as measured at the discharge point of the fluid reservoir.
11.2.15 After the additional 60 cycles have 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. This is the 90-cycle sheared sample. Remove the thermometer assembly or probe.
11.2.16 Using Test Method D445, determine the kinematic viscosity at 100°C of unsheared (untested) test oil, as well as the 30-cycle sheared sample (from 11.2.10) and the 90-cycle sheared sample (from 11.2.15). Use the same viscometer tube for the measurement of each sample.
12. Calculation
12.1 Calculate the percent viscosity loss (PVL) of the sheared oil samples as follows:
PVL30 = 100 [(Vu - V30)/Vu]
PVL90 = 100 [(Vu - V90)/Vu]
where:
Vu = kinematic viscosity of unsheared oil at 100°C, mm2/s,
V30 = kinematic viscosity of the 30-cycle sheared oil sample at 100°C, mm2/s, and
V90 = kinematic viscosity of the 90-cycle sheared oil sample at 100°C, mm2/s.
