The rotational viscometer is used to measure the viscous resistance and dynamic liquid viscosity of liquids, and is widely used to measure the viscosity of various liquids, such as oil, paint, plastic, food, medicine, cosmetics, adhesive products, etc. etc.
Working principle of the rotary viscometer:
1. Working principle:
When measuring, the inner cylinder is Simultaneous with the outer cylinder submerged in the drilling fluid, they are concentric cylinders with an annular gap of 1.17mm. As the outer cylinder rotates at constant speed, it drives the drilling fluid in the annulus to rotate.
Due to the viscosity of the drilling fluid, the inner cylinder connected to the torsion spring rotates at an angle. According to Newton's law of internal friction, the magnitude of the angle of rotation is proportional to the viscosity of the drilling fluid, so themeasuring the viscosity of the drilling fluid is converted into measuring the angle of rotation of the inner cylinder.
The size of the rotation angle can be read directly from the dial, which is why this viscometer is also called a direct-read rotation viscometer.
2. Measuring principle:
①Relationship between shear rate and rotation speed: 1 rpm (generally expressed as rpm) = 1.703 s-1 ;
②The indicator q (q is degree on circumference, unit can be omitted) is proportional to shear stress t (unit is Pa). If the designed torsional spring coefficient is 3.87?10-5, the relationship between the two can be expressed as follows: t = 0.511 q (Pa).