Volume 4, Issue 8, 01 August 1933
Index of content:
4(1933); http://dx.doi.org/10.1063/1.1745191View Description Hide Description
Flow measurements on bentonite suspensions, showing both the property of thixotropy and of fluidity variable with shearing stress, were performed in capillary tubes, brass pipes, and a rotary consistometer of special design. The latter instrument was used to show that the structure of such gels must be broken down or built up until an equilibrium state of flow is attained to obtain reproducible measurements. No slippage at the walls was found in non‐plug flow.Turbulent flow of bentonite suspensions was investigated in one‐half and one‐inch pipes. It is demonstrated that these materials behave as any viscous liquid, in the turbulent region, and that the volume of flow at any pressure gradient may be assumed to be the same as for water, without great error. The importance of obtaining equilibrium flow conditions for fluidity measurements is stressed.
4(1933); http://dx.doi.org/10.1063/1.1745192View Description Hide Description
An apparatus designed for the precise measurement of absolute viscosity is described. The liquid being studied is caused to flow from one reservoir through a capillary tube into a second reservoir, the pressure difference between the two being measured with a differential manometer. Various rates of flow are caused by injection of mercury into the upstream reservoir from a cylinder by means of a uniform piston driven at constant speed by a synchronous motor through a gear train. A number of interchangeable capillaries of different bore diameters and lengths can be employed. The displacement apparatus and the viscometer are thermostated in baths designed for precise temperature control. A machine designed and built to lap the bores of capillaries into right circular cylinders is described.
4(1933); http://dx.doi.org/10.1063/1.1745193View Description Hide Description
The viscous resistance offered by a tube of varying radius to the flow of a liquid is discussed. Three cases are taken up, for which solutions assume the forms:
(1) capillary tube viscometer:
(2) Bingham and Murray plastometer:
(3) apparatus for studies of wetting under dynamic conditions:The functions AL, f 3(l), and f 5(l), may be obtained from a calibration of the tube, use being made of graphical integration.
The Balance‐Plastometer; a Simple Instrument for Measuring Plasticity and Recovery of Soft Materials4(1933); http://dx.doi.org/10.1063/1.1745194View Description Hide Description
4(1933); http://dx.doi.org/10.1063/1.1745195View Description Hide Description