Frictional Coefficient Tester model in NZ-3A is used to evaluate the quality and reasonable compatibility of drilling fluid lubricants.

The instrument is mainly composed of a box body, a cover box, a working slide plate, a LCD screen, a transmission mechanism, a micromotor, a slider and a sliding rod, etc.

The instrument uses digital display to show data directly, which has the characteristics of compact structure, high test precision, convenient and reliable operation, good repeatability and easy carry. It is an essential instrument for drilling fluid analysis.

Under the inclined condition of the working slide plate, the slide block placed on the mud cake is subjected to downward gravity, and begins to slide after overcoming the viscous force. As shown in picture. 1. According to Newton's friction law:

Friction coefficient：

Let the weight of the slider be W, and the component force parallel to the inclined plane be F, that is, friction force. The vertical one is p, that is, positive pressure. All the process, please see triangle relationship to explain. (see figure 1)

SO, F=Wsinα       P=cosα

friction coefficient when the slider begins to slide down：

Also known from the similar triangles relationship,

∠α=∠β   故  tgα=tgβ

And ∠ β is measured by the instrument, so tgβ is the friction coefficient of mud cake, that is, the friction coefficient of mud cake is the viscosity coefficient measured by the instrument.