FI109240B - Method for establishing the flow potential of an aqueous solution and arrangement for application of the method - Google Patents

Description

, 109240

METHOD FOR DETERMINING THE FLOW POTENTIAL OF AQUEOUS SOLUTION AND THE APPLICATION OF THE METHOD

The invention relates to a method for determining the flow potential 5 of an aqueous solution. The invention further relates to a device for applying the method.

The determination of the surface charge of dissolved, colloidal, substances in an aqueous suspension is important to understand the properties of the aqueous solution. Current methods for determining the charge state of aqueous solutions are based on either color change reduction with polyelectrolyte and indicator dyes, or determination of flow potential in the narrow gap between the piston and cylinder of an electrically insulated cylinder / piston assembly.

The disadvantage of these methods is that the interfering substances are sensitive to the color change reaction, which makes accurate determination difficult and dependent on the analyzer. In the cylinder / piston combination, the solution is incomplete and therefore the determination time is long. It is also a disadvantage that these assays are not suitable for solutions having particles of a fiber size or larger, but must be filtered first. 20 specifications.

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• 1 • ·> 1 1 • · ·. The flow potential of aqueous solutions is determined by various industries, and in particular: "in the paper industry, where the determination of the properties of paper pulp solutions is important to monitor the properties of the paper.

It is an object of the invention to provide a method for overcoming the drawbacks of the present methods. In particular, it is an object of the invention to provide E ': a method which is insensitive to interfering agents and an accurate assay can be performed automatically, in a relatively short period of time, on all kinds of solutions, independently of the assayer. It is a further object of the invention to provide a device

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»· To apply a method that is simple in design, easy to use, and easy to use 2 109240.

The object of the invention is achieved by a method and a device characterized by what is stated in the claims.

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In the method of the invention, the aqueous solution to be examined is directed to an ejector, and a pressurized gas is simultaneously introduced into the ejector, whereupon the aqueous solution to be examined is mixed with the gas and the voltage difference caused by the flow is measured by The method quickly and simply determines the flow potential of the aqueous solution. The method substantially speeds up the determination of the flow potential of the aqueous solution in comparison with previously known methods, and at the same time provides more reliable results. This provides a faster and more accurate determination of the concentration of the aqueous solution as compared to the previous one. The method is suitable for use as an automated assay. This saves labor costs.

The method can be used to automatically determine the flow potential of various aqueous solutions. The method is particularly suitable for use in the paper industry to determine the properties of aqueous solutions. The method allows direct examination of pulp solutions and does not necessarily require filtration to separate the solid from the aqueous solution. whereby the results of the analysis of '·' 25 are immediately available

In a preferred embodiment of the invention, the aqueous solution to be examined is introduced into the ejector through a suction tube and the voltage difference is measured at the electrode and; between the electrode in the suction tube. Such a solution is simple and inexpensive to implement. It is also possible to place the latter electrode in a reservoir, from which the test solution is led to the ejector.

, 109240

In another preferred embodiment of the invention, compressed air is supplied to the ejector. The use of compressed air is advantageous and suitable for this purpose. Other pressurized gases such as nitrogen or other suitable gas may also be used in other applications.

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In a third preferred embodiment of the invention, compressed air is supplied to the ejector through a nozzle located in the tube. The nozzle allows the compressed air to be effectively mixed with the aqueous solution.

In a further preferred embodiment of the invention, the fluid examined is recycled from the ejector back to the dispensing container. In this case, other determinations can be made as desired.

The device according to the invention comprises an ejector having an inlet tube for introducing an aqueous solution 15 into the ejector and a tube for introducing pressurized gas into the ejector, connected thereto electrodes for initiating the reference potential of the solution and a voltage gauge for measuring the difference between these electrodes. Such a device is simple in structure, advantageously manufactured and reliable.

The invention will now be explained in more detail with reference to the accompanying drawing, which is a side view showing a principle view of an apparatus of the invention.

The flow member, i.e. the ejector 1 with the interconnected tube 2, the discharge tube 7 and the suction tube 4. The device also includes an electrode 3 located in the ejector outlet tube 7, a second electrode 5 in the suction tube 4 and a voltage meter 6. tube 2 '' is connected to exhaust pipe 7 and tube 2 has a nozzle 8. Suction tube 4 is connected; ' In addition, the device includes or is connected to compressed air devices, electronics and measuring signal processing devices known per se 109240 4, and a computer, which are not described in further detail.

The flow potential of the aqueous solution is determined using the method and apparatus of the invention as follows: The aqueous solution to be determined is directed to the ejector from a dosing tank or the like via a suction line 4. The potential of this aqueous solution is measured by electrode 5 placed in the suction tube. At the same time, purified compressed air (or other gas) is introduced through tube 2 and nozzle 8 into the ejector. Compressed air creates a vacuum in the ejector relative to the suction tube by which the solution to be assayed is drawn into the ejector. The solution to be assayed is then effectively mixed with compressed air and the rate of the combined air / water mixture increases substantially. The flow potential of the resulting air / water mixture is determined by the electrode 3. The voltage difference formed between the electrodes 3 and 5 is measured by a voltage meter 6 and this information is directed to signal processing. The signal is processed by a computer and the results reported as desired. The combined air / water mixture is blown out of the ejector outlet 7. The measurement is continuous and automatic.

The apparatus is easy to clean and the rinsing of the suction line and the outlet line is accomplished by changing the test solution to the washing or rinsing solution. Calibration procedure:: 20 by dispensing polyelectrolytic solution into suction line. When not in use, the ejector is flushed with deionized water and emptied. Washing / cleaning, rinsing calibration can be done automatically according to a preselected program ··· * 25 The invention is not limited to the preferred embodiment shown, but may vary within the scope of the inventive idea of the claims.

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Claims (7)

A method for determining the flow potential of an aqueous solution, characterized in that the aqueous solution to be examined is guided into an ejector (1), and that the ejector is simultaneously conducted under pressurized gas, wherein the aqueous solution to be examined mixes with the gas, and that, with the aid of electrodes (3, 5), the voltage difference measured by the current is measured by a voltage meter (6). 2. A method according to claim 1, characterized in that the aqueous solution to be examined is fed into the ejector (1) through a suction tube (4) and the voltage difference is measured between the electrode (3) located in the ejector and the electrode (5) located in the suction tube. 3. A method according to claim 1 or 2, characterized in that the injector (1) is led to compressed air through a tube (2). 15 4. A method according to claim 3, characterized in that compressed air is supplied to the ejector (1) through a nozzle (8) located in the tube (2). 5. A method according to any one of claims 1-4, characterized in that the liquid being examined is guided from the ejector back to the dosing container. Apparatus for determining the flow potential of an aqueous solution, characterized in that the apparatus hears an ejector (1) having a suction pipe (4) for conducting: the aqueous solution for the ejector and a pipe (2) for conducting the pressurized gas to the ejector, the flow potential of the associated solution measuring the electrodes (3, 5) and a voltage meter (6) measuring the voltage difference between the electrodes (3, 5). An apparatus according to claim 6, characterized in that one electrode (3) is located in the ejector (1) and the other electrode (5) is located in the suction tube (4). 30; 35