b) Calibration of the capillary vis

b) Calibration of the capillary viscometer with normal oils of the PTB During this calibration, a normal oil from the PTB with known viscosity is used as a reference measuring standard. The measurement is performed by means of flow-through measurement of the PTB normal oil in the viscometer to be inspected in a temperature bath, the temperature of which must correspond precisely to the test temperature of the PTB. In this case, it is extremely important to make sure that the temperature is absolutely correct. In case of temperature variation, this will always result in a constant for the viscometer that deviates from the constant applied. A temperature variation of0.01 K, for instance, will result in a measuring error of up to 0.01 %. The calibration of the deviating temperature into the viscometer constant is not permitted.