Method and device for measuring the characteristics of plastic fluid and

Abstract

The fluidity of a plastic fluid, cement mortar for example, is measured by passing the fluid through a flow passage packed with an aggregate for simulating an actual mould, measuring the flow pressure, and measuring the quantitative flow coefficient between the fluid and the flow passage. The pressure remaining in the passage after the fluid has been poured into the passage and after the flow speed has been decreased to zero or the pressure after a quantity of the fluid has been added to the passage and prior to the discharge of the fluid from the passage is measured to determine the relative shear stress yielding value. Thereafter, the fluid is caused to flow to determine again the relative shear stress yielding value, and the relative closure coefficient is determined by the difference between said two relative shear stress yielding values. After the elapse of a predetermined time the plastic fluid is caused to flow under a pressure and the pressure at the commencement of the flow is measured to quantitatively determine the variation in the shear stress yielding value with time, thereby determining the relative initial flow pressure. The relative flow viscosity coefficient is measured by varying the flow speed of the plastic fluid and by determining the relationship between the speed and the pressure of the plastic fluid. In the actual moulding operation the plastic fluid is prepared by using the factors thus determined and the pouring conditions are predetermined, or automatically controlled.