How to measure the mud density meter

Mechanical mud density meters need to be tested for discrimination, which is also called sensitivity limit. It mainly checks the integrity of the knife edge and knife bearing of the mechanical mud density meter. Because the pressure on the knife edge and knife bearing is the largest at full scale, the instrument's discrimination value is the largest, so the discrimination should be tested at full scale. The smaller the discrimination value is, the worse the durability of the instrument is, and it cannot meet the harsh environmental conditions of the construction site. Since electronic mud density meters do not have knife edges and knife bearings. Therefore, electronic mud density meters do not perform discrimination tests.

The zero point adjustment of the mechanical mud density meter is very important for the mud density meter. The accuracy of the zero point will affect the indication errors of other points. Since the density of the zero point is traced back to pure water, it is necessary to use clean pure water; the sample cup should be prevented from tilting during operation, as bubbles are easily retained in the tilted sample cup, which will cause the zero point to produce error errors; when adjusting the counterweight of the adjustment chamber, the zero point adjustment should be performed with the adjustment chamber cover covered; the zero point adjustment of the pressurized mud density meter should be paid more attention to, and it must be performed when the sample cup is pressurized, otherwise, if the pressurization valve is not closed, there will be a large error in the zero point adjustment.

If the zero point adjustment of the mud density meter is accurate, but the indication error of the instrument increases or decreases linearly with the increase of the measurement point, then the mass of the mud density meter's sliding weight changes due to wear and other reasons and does not match the scale. It can be adjusted by adjusting the mass of the sliding weight, and this work should be performed by the manufacturer.

The adsorption of water by the inner wall of the sample cup will cause the mud density meter to produce systematic errors, especially for the pressurized mud density meter, the inner wall of the metal sample cup and the cup cover of the pressurized air hole will absorb a lot of water, increasing the measurement error. For this reason, the procedure adds a method for handling liquid residues to improve the accuracy of the measurement.

Whether the position of the substitute is evenly placed has a great influence on the measurement results. Therefore, attention should be paid to the uniformity of the placement of the substitute to eliminate the influence of eccentric load on the indication of the mud density meter.