6. Apparatus
6.1 Two types of apparatus are available for use in this test method: the manual cold-cranking simulator (see 6.2) and the automated CCS (see 6.3 and 6.4).
6.2 Manual CCS8, consisting of a direct current (dc) electric motor that drives a rotor inside a stator; a rotor speed sensor or tachometer that measures rotor speed; a dc ammeter and fine current-control adjust dial; a stator temperature control system that maintains temperature within more or less 0.05°C of set point; and a coolant circulator compatible with the temperature control system. See Fig. 1.
6.3 Automated CCS, consisting of the CCS described in 6.2, with computer, computer interface, and test sample injection pump. The methanol circulator (see 6.6.1) is not used because the test sample injection displaces the previous test sample. See Fig. 2.
6.4 Automatic Automated CCS - The CCS described in 6.3 with the addition of an automated sample table allowing up to 30 test samples to be run sequentially under computer control without operator attention. See Fig. 3.
NOTE 1 - In some CCS instruments, the refrigeration may be achieved using solid state thermoelectric modules.
6.5 Calibrated Thermistor - Sensor for insertion in a well near the inside surface of the stator to indicate the test temperature.
6.6 Refrigeration System - A refrigerator for the liquid coolant is needed to maintain coolant temperature at least 10°C below the test temperature. Mechanical refrigeration is preferred, but dry ice systems have been used satisfactorily. The length of the tubing connections between the CCS and the refrigerator should be as short as possible and well insulated.
NOTE 2 - Thermoelectric cooling may be used instead of mechanical refrigeration or use of dry ice, and so forth.
6.6.1 There must be good thermal contact between the temperature sensor and the thermal well in the stator; clean this thermal well periodically and replace the small drop of high-silver-containing heat transfer medium. Adjust the temperature of the coolant to the viscometric cell to be at least 10°C below the test temperature.
NOTE 3 - If a thermoelectric cooling system is used in the instrument, the liquid cooling temperature of the water or other appropriate liquid used in the refrigeration system (chiller) should be set to approximately 5°C in order to maintain the sample test temperature.
6.6.1.1 To ensure optimum control of temperature using the dry-ice system, the valve settings on the coolant circulator are set for control of coolant with a low-viscosity test sample in the viscometric cell and the simulator motor turned on.
6.7 Coolant, dry methanol - If contaminated with water from operating under high humidity conditions, replace it with dry methanol to ensure consistent temperature control, especially when cooled by dry-ice.
6.8 Optional Methanol Circulator - This option (for the Manual CCS only) circulates warm methanol through the stator to facilitate sample changes and aid the evaporation of cleaning solvents.
