SU68554A1 - A device to prevent the formation of scale in boilers - Google Patents

Description

The purpose of the present invention is to provide effective scale control in steam boilers by utilizing the kinetic energy of the steam passing through the pipelines, which, when the steam is rubbed on specially installed points, is converted into an electrostatic charge, which imparts a negative potential to the walls of the boiler.

The use of hitherto purely electric methods of combating scale, including the proposed electrostatic method, as it was put into practice, has a significant disadvantage, which in many cases prevents their widespread use. This drawback lies in the fact that insulated electrodes, whose positive potential causes the process of separating and strengthening salt particles that fall out of the boiler water, quickly become covered with a strong layer of scale and are not able to support each other and the walls of the boiler.

potential difference required for normal operation of the entire device. To periodically clean the electrodes, it is necessary to remove them from the boiler each time, first disconnecting and stopping the boiler and letting off steam. The complexity of electrode cleaning cannot justify all the advantages of electrochemical methods of protection against scale.

The versatility and automaticity of the proposed method is determined by the design of the device, designed to permanently maintain the surface of the anodes in a metallic pure state.

FIG. 1 shows a part of a longitudinal section through the boiler with a device, and FIG. 2 - part of the cross section of the boiler.

In a steam boiler of a steam boiler, from which steam is extracted, a plate is installed in the form of a copper disc A equipped with ground stainless steel points.

The disk A is mounted on the insulator S, which is attached to the body.

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boiler with a movable bracket with a be. Disk A is connected by flf conductors made of copper wire with water-resistant elements of the boiler.

To increase the speed of steam flow past the tips and above the latter, a cylindrical screen E is installed.

The operation of the described device is based on the fact that steam, which contains a significant amount of electricity, strikes the point of the disk A, transfers electric charges to it. The latter, spreading through the connecting wires d over the entire heating surface, force the solid parts falling out of the water during boiling, contacting the walls of the boiler or pipes, to be charged with the same kind of electricity as the walls of the boiler. Due to this circumstance, these particles are repelled from the same charged elements of the boiler; scale, unable to settle on the walls of the boiler and the piping system, should be aggregated and collected on the surface of the water, from which it can be removed by boiler purge.

Old solidified scale under the action of electric current passing between the walls of the boiler and the disk A through the water and a layer of steam above it, which is not an insulator in this case, due to a number of reasons as an insulator, gradually loosens and falls behind on the walls of the boiler. its bottom is in the form of sludge easily removed during purging.

It must be emphasized that the successful application of such a method of combating scale formation depends primarily on the contact density of the conductors and on the absolute purity of the metal surface of the needle-shaped tip electrodes. The operation of these electrodes is most effective and stable, provided they are made of stainless steel with a well-polished, non-oxidized surface. To ensure absolutely smooth128

After their installation on the plate, they should be re-sanded to the full length, up to the point of their attachment. From the physico-chemical point of view, the deposition process in this case would have to proceed as follows: under the action of electrodes placed inside the boiler, continuously giving a positive charge to the protected surface, scale particles suspended in boiling water, due to the so-called phenomenon of electrophoresis, should strive to positively charged poles and deposited on them, at the same time enlarging in their size.

However, the well-polished side surfaces of the tips cannot hold the particles deposited on them and the latter, gradually growing, should fall down from them to the bottom of the boiler, not adhering to its walls due to their sufficient coarsening (similar to the mechanism of action of many anti-scaling).

Despite careful polishing of the needles, the sediment consisting of the smallest suspension of insoluble salts should gradually cover with the thinnest, but electrically sufficiently dense (in the sense of insulating properties) layer the active part of the electrodes and, as a result, increase their electrical resistance to reduce the scaling effect. .

To prevent this phenomenon, the pointed disk A, which plays the role of a central positive electrode, can be tilted around the hinge with the help of a rod B pulled out of the steam space and submerged in water for cleaning. At this time, one or more auxiliary well-electrically insulated (g-g) electrodes, installed slightly below the normal water level in special hatches, are put into operation.

Each electrode consists of a central metal rod L / c flange and a cut-off part of the t passing through the lid of the corresponding hatch. Rod elek