Calibration of flow cup viscometer

The viscosity meter calibration procedure is applicable to the calibration of newly manufactured, used, and repaired outflow cup viscometers. The standard viscosity liquid (hereinafter referred to as the standard liquid) with known kinematic viscosity should have a difference between the measured and calculated values of the outflow time from the outflow cup viscometer within the range of the calculated value; Within 3%.

Calibration Procedure for Flow Cup Viscometer:

This calibration procedure is applicable to the calibration of newly manufactured, used, and repaired flow cup viscometers.

1、 Technical requirements

1. The difference between the measured and calculated values of the outflow time of the standard viscosity liquid (hereinafter referred to as the standard liquid) with known kinematic viscosity from the outflow cup viscometer should be within ± 3% of the calculated value.

2. The inner wall surface of the outflow cup viscometer must be smooth and free of willow patterns, scratches, etc.

3. The outflow pipe must be a straight pipe with a smooth inner wall and no burrs. The connection between the outflow pipe and the inner wall of the cup should be smooth, and there should be no gaps after replacing the outflow pipe.

4. Before calibrating the flow cup viscometer, it must be labeled with the name, number, inner diameter of the flow tube, manufacturer, etc.

2、 Calibration conditions for outflow cup viscometer

1. Calibration equipment

1.1 Standard solution (should have a kinematic viscosity value at the instrument calibration temperature).

1.2 Water residual thermometer that has been verified as qualified and has a division value not exceeding 0.1 ℃ (the reading should be corrected when in use).

1.3 Sand table or timer that has been verified as qualified and has a division value not exceeding 0.1s.

1.4 Bubble level.

1.5 flat glass panel or straight edge scraper.

1.6 Supervision of the Sex and Stone Market

A constant temperature bath or constant temperature box (with refrigeration equipment) with a temperature control accuracy of no more than 0.5 ℃.

1.8 Receiving beaker (with a volume greater than the outflow cup viscometer).

2. Environmental conditions

The calibration temperature is any temperature between 20~30 ℃, and the laboratory temperature (within 2 hours) is controlled within ± 1 of the calibration temperature.

3、 Verification items and methods

1. Preparation work

1.1 Place the appropriate grade of standard solution (with an outflow time of 30-100s) into a constant temperature bath (if using a constant temperature box, place the standard solution and outflow cup viscometer together), and maintain it at the calibration temperature of ± 0.5 ℃ for 20-30 minutes.

1.2 Wash the outflow cup viscometer with gasoline, alcohol, and petroleum ether. Use a silk cloth dipped in solvent to clean the outflow tube, and then dry it for later use.

2. Determination of outflow time

2.1 Place the outflow cup viscometer on the dedicated bracket, adjust the horizontal screw to make the upper edge of the outflow cup viscometer horizontal (checked with a level). Place the receiving beaker under the outflow tube.

2.2 Use a thermometer to measure the temperature of the constant temperature standard solution. When it reaches the calibration temperature of ± 0.1 ℃ (when the room temperature is within the positive fluctuation range of the calibration temperature, the standard solution should be pre lowered by 0.5 ℃, and vice versa), move the thermometer into the receiving beaker, block the outflow tube with your fingers, pour the standard solution along the inner wall of the outflow cup viscometer until the liquid overflows, and use a straight edge scraper to scrape it flat until the liquid surface is level with the upper edge of the outflow cup viscometer (the temperature change of the standard solution from pouring into the outflow cup viscometer to flowing out of the outflow tube into the receiving beaker should not be greater than 0.1 ℃).

2.3 Remove the fingers and time simultaneously. The liquid should flow out of the outflow pipe in a straight line. Stop timing at the moment of interruption and record the outflow time t1.

2.4 Re measure the temperature of the standard solution using the above method and record the outflow time t2. Then calculate the average value. The difference between two measurements shall not exceed 2% of the average value.

2.5 Choose another brand of standard solution and repeat the above operation, and record the data.

Calculate the standard liquid outflow time according to the following formula:

The following are the reference measurement ranges for standard solutions:

The above is the calibration related content of the flow cup viscometer. Generally speaking, the calibration cycle for this equipment is one year, and repaired viscometers must be calibrated and used only after passing the inspection.