JPS58124927A - Measuring method of wetting speed of powder - Google Patents

Abstract

PURPOSE:To measure the wetting speed of powder by liquid by packing powder samples in a cylindrical body, bringing the bottom part thereof into contact with liquid, and detecting the ascending speed of the liquid from the change in the resistances between the electrodes provided at required intervals in the cylindrical body. CONSTITUTION:Powder samples are beforehand packed in a cylindrical body 1 to form packed layers 2, and after the time feed of a pen recorder 9 is started, the liquid level in a vessel 4 is moved upward until liquid 5 contacts the powder layers 2. When both contact, a lamp is lighted in a detector 8 and the start is confirmed. When the liquid ascends by capillarity, the electric conductivities between the electrodes provided at every required interval in the body change and the output voltage for the recorder increases by every specified graduation. A stepwise graph is plotted on the recorder. If the graph is redrawn to a smooth curve, the relations between the front line position of the liquid and time are made continuous; therefore, the ascending speed of the liquid in each position is obtained by operations such as graphical differentiation.

Description

DETAILED DESCRIPTION OF THE INVENTION 423 The present invention relates to a method for measuring the wetting rate of powder with a liquid.

It is difficult to measure these physical properties, and the development of an appropriate measurement method has been desired.

The present invention has been made to satisfy the above-mentioned needs, and according to the present invention, a powder layer is formed by filling a cylinder with powder,
When the bottom of this powder layer is brought into contact with a liquid, the liquid rises in the powder layer due to capillary action. Provided is a method for measuring the wetting rate of powder with a liquid, which is characterized by detecting a change in conductivity.

Next, the present invention will be explained with reference to the drawings.

In Fig. 1, 1 is a cylindrical body, 2 is a powder filled in the cylindrical body,
3 is an electrode provided inside the cylinder, 4 is a container containing liquid 5, 6 is an electrode provided in the liquid, 7 is a filter installed at the bottom of the cylinder, 8 is a detection device, and 9 is a pen recorder. show.

According to the present invention, a powder sample is filled in a cylinder in advance to form a packed layer, but after starting the time advance of the recorder, the cylinder containing the sample is slid or the liquid level of the container is raised. The liquid is brought into contact with the powder layer, and when the liquid comes into contact with the bottom end, a lamp lights up on the detection device to confirm that the powder has started. As the liquid permeates and rises, the output voltage for the recorder increases at a constant rate each time it passes through the electrodes, and a step-like graph is drawn on the recorder.

The analysis of Guku7 is based on the following method.

In other words, if we transform the step-like graph above into a smooth plot, the front position of the liquid rising through the powder layer and the 0-field relationship will become continuous, so we can calculate each value by 0-search, such as graphical differentiation. The rate of rise of the liquid at the position cannot be obtained.

1. Wetting of the powder by the liquid obtained in this way has a meaning in itself.Furthermore, from the graph showing the wetting process, we can calculate the capillary diameter at the powder layer position 08- By knowing the distribution in the height direction and either the contact angle or the fat tension in the powder-liquid system, information necessary to calculate the other information can be obtained. Wash
According to the formula of burif, the rising speed of the capillary can be expressed as in formula (1).

On the other hand, the capillary pressure Δp in equation (1) is expressed by the following equation and is the meniscus height.

By combining (1) and (2), the capillary diameter of the powder layer at a certain height h can be calculated as follows using the capillary rise rate determined by graphically processing the graph obtained by measurement. By using a bow, either the contact angle or the interfacial tension is known from the dog, and the other can be calculated if possible.

If the affinity between the liquid and the powder is small and the rising position of the liquid rising up the powder layer is too low and difficult to measure, use the water head difference to forcibly raise the liquid to a certain level. The wetting process of powders under various vacuum conditions can be tracked by Py.

FIG. 2 shows an example of a 6 measuring device for carrying out the present invention, which is equipped with this pressure reduction system.

In Fig. 72, 10 is a base, 11.12 is a support provided on the base, 13 is a lid that holds the powder layer inside, 16 is a lead wire from an electrode, and the other end is a detection device ( (not shown). A suction pipe 18 is connected to an upper water tank installed in the upper frame 24 of the gantry via a solenoid valve 19. Reference numeral 20 denotes an electric wire that sends a signal from the detection device to operate the solenoid valve. 23 is the airtight lid of the upper water tank. 25 is as follows: 5- By sliding the support 26 on the drain pipe from the upper water tank 22, the drain position 27 slides on the scale, thereby creating a water head difference.

The container 30 (starter) contains a sample liquid, and by moving this level, for example, the liquid level in the lower liquid tank is raised and the lower end of the powder bed is brought into contact with the liquid.

For measurement, first close the solenoid valve 19, move the support 26 until a predetermined water head difference is achieved while watching the position of 27, drain some of the water in the upper water tank, and wait until the end of the measurement. Next, the starter is moved to bring the lower end of the cylinder into contact with the liquid in the lower water tank, but at the moment of contact, an electrode installed at the bottom of the cylinder sends a signal to the detection device, which simultaneously opens the solenoid valve.

As a result, the inside of the cylinder is brought into a predetermined reduced pressure state, and the permeate rises within the powder layer to a position higher than that at normal pressure by the amount equivalent to the difference in water head converted into liquid.

Needless to say, the subsequent process of liquid level rise can be detected in the form of a step graph using the same procedure as at normal pressure. When reducing the pressure, if the height of the water column corresponding to the reduced pressure is h2, equation (2) will be reduced using the water head difference, and the forms of equations (3) and (4) will also change.

In the present invention, substances with high conductivity among organic solvents and the like can be considered as the powder to be measured.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of an apparatus system for implementing the method of the present invention, and FIG. 2 is an overview diagram of a measuring device used for implementing the method of the present invention. 1... Cylindrical body, 2... Powder, 3... Electrode, 4...
Container, 5...Liquid, 6...Electrode, 3...Electrode, 7
. . . Filter, 8 . body, 17.
...liquid tank, 22...water tank, 32...drainage tank.

Claims (2)

[Claims] (1) By filling a cylinder with powder to form a powder layer and bringing the bottom of this powder layer into contact with a liquid, the speed at which the liquid rises from the bottom of the powder layer due to capillary action is increased. A method for measuring the wetting rate of powder with a liquid, characterized in that detection is performed based on changes in electrical conductivity between electrodes provided at required intervals within the cylinder. (2) The method according to claim 1, in which the liquid is raised upward into the powder bed under reduced pressure conditions.