RU2495724C2 - Flotation aerator - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention can be used in oil production and processing, petrochemical, food and light industries, ferrous and nonferrous metallurgy and machine building. Flotation aerator comprises housing baffle 10 with central bore to divide its inner chamber in top and bottom zones 2, 3; water inlet arranged at bottom zone lower area, air duct 7; water-air mix outlet; motor 1 with impellers 5, 6 fitted on shaft 4 arranged in housing different zones. Said baffle 10 represents a diaphragm. Air duct 7 is connected with top zone 2. Water-air mix outlet is composed of perforation in housing bottom zone sidewalls. Impeller 6 arranged at bottom zone 3 is composed of rotor with vertical replaceable vanes. Said vanes feature perforated and/or toothed edges. Water discharge into bottom zone is effected via detachable control diaphragm 12 with central bore and nozzle 22.

EFFECT: higher efficiency of fine air-water mix and reliability of operation.

9 cl, 2 dwg

Description

The present invention relates to flotation aerators and is used for aeration of natural and other bodies of water for oxygen enrichment of water, for aeration of water in water and wastewater treatment systems, and also as an apparatus for dispersing air (gas) in wastewater treatment by flotation and can be used in the field of oil refining, petrochemical and oil producing industries, as well as food and light industry plants, ferrous and non-ferrous metallurgy enterprises, machine-building plants.

A known aerator comprising a housing with an inlet for water, an outlet for the air-water mixture and a partition dividing its space into upper and lower zones, wherein an opening for supplying air is made in the partition; air duct

an electric motor with two impellers (impellers) mounted on its shaft installed in different zones of the housing (US patent No. 6655663).

In the known aerator, water is introduced into the lower zone of the housing, the air-water mixture is discharged laterally from the upper zone, and the air duct is introduced into the hole made in the partition. Air is sucked in due to the Venturi effect that occurs when a water stream passes from the high-pressure region created by rotation of the first impeller into the low-pressure region created by the second impeller.

Known aerator has several disadvantages. So, the mixing of water and air with the upper impeller is carried out in a sufficiently large volume, and the air-water mixture is removed from the side. In the upper part of the aerator body there is an area where sucked air accumulates and an air cushion is formed. The accumulated air in large bubbles escapes through the side opening, thus blocking part of its cross section, which leads to both a decrease in the productivity of the apparatus and the effect of aeration. Air is sucked into the dispersion region due to the Venturi effect that occurs when water flows through the housing region containing the baffle from the high pressure zone to the low pressure zone. The volume of intake air, in this case, depends on the discharge (vacuum) created by the flow of water in the area of the partition. To change the proportions of the mixed components (water and air), in this case, it is not possible, since all the ratios of the geometric dimensions of the apparatus and the parameters of the electric motor are initially constant and not adjustable. Changing the proportions of water and air with stirring affects not only the saturation of water with air, but also the size of air bubbles, which is important in the processes of water purification by flotation and to increase the effect of aeration.

Dispersion of air in water is carried out in a wide part of the upper zone with large gaps between the wheel blades and the walls, which leads to the formation of bubbles of relatively large diameters. Other disadvantages of the aerator include the location of the electric motor inside the housing in the zone of formation of the air cushion, which may cause it to overheat.

The objective of the present invention is to increase the efficiency of aeration of water and the reliability of the device.

In a flotation aerator containing a housing containing a partition with a Central hole, dividing its space into upper and lower zones; water inlet located in the lower part of the lower zone; air duct the conclusion of the water-air mixture; an electric motor with impellers (impellers) mounted on its shaft located in various zones of the housing, according to the invention, the partition is made in the form of a diaphragm with a central hole, the air duct is connected to the upper zone, and the air-water mixture is discharged in the form of perforation in the lower zone of the housing. The air duct contains a regulating device for regulating the air supply, located in its upper part and above the water level, the electric motor contains a shaft speed controller, and the water inlet contains a regulating device for regulating the water supply, containing a guide diaphragm with a central hole, and nozzles attached to the bottom parts of the lower zone. The electric motor is mounted on the upper surface of the housing. The diaphragm is removable and may have a different diameter of the central hole, the size of which is set depending on the depth of immersion. The impeller located in the lower zone is made in the form of a rotor with vertical interchangeable blades having a different configuration. The impeller blades are rectangular. The blades are perforated and / or with serrated edges. Perforation in the lower zone of the housing is made with a given frequency and diameter of the holes. The impeller located in the upper zone of the housing is made in the form of a wheel with helical blades. The gap between the outer edge of the impeller blade and the perforated wall is 5-10 mm.

The proposed flotation aerator eliminated all the design flaws of the known aerator and provides the ability to control the process of obtaining a finely dispersed water-air mixture. So, the dispersion of air in water is carried out in the cramped volume of the dispersion chamber, with a small gap between the perforated blade and the perforated chamber wall, comprising 5-10 mm. The water-air mixture is removed through the perforated side walls of the lower zone in which the dispersion occurs, with calculated perforation. The increase in the size of the bubbles and the accumulation of air in the apparatus, in this case, does not occur. Perforated and / or toothed blades of the impeller of the lower zone contribute to better mixing of water and air by increasing the zones of turbulence in the lower zone of the casing not only at the edges of the blades, but also the holes of the blades. In addition, the implementation of the blades perforated and / or with serrated edges increases the turbulization of the medium, which leads to an increase in the number of bubbles due to cavitation.

Performing the withdrawal of the water-air mixture through the perforated side walls of the lower zone in which the dispersion occurs, contributes to the uniform dispersed release of the water-air mixture into the aerated volume of water. Air enters the upper suction zone through the upper impeller through an air duct with a control device, and into the lower zone where dispersion occurs (via a removable control diaphragm), by the lower impeller, which creates a vacuum during rotation. Water enters the dispersion zone through a regulating device for regulating the water supply, containing a guide diaphragm with a central hole, and nozzles due to hydrostatic pressure and vacuum created by the second impeller during rotation. Thus, the supply of air and water to the lower zone are independent of each other. Regulating devices for regulating the supply of water and air, as well as a speed controller for the motor shaft, allow you to change the proportions of the mixed components independently of each other. The hole diameter of the removable control diaphragm is selected depending on the immersion depth of the apparatus - the diameter of the hole is reduced with increasing immersion depth of the flotation aerator. The configuration of the interchangeable blades can be changed depending on the operating conditions of the flotation aerator and the properties of the processed fluid. The nozzles ensure that water is drawn from the lower layers, improving the circulation of water in the aerated volume. The electric motor is completely in the volume of aerated water in the aeration zone, which contributes to its effective cooling.

Thus, the use of the above features makes it possible to increase the reliability of the device when the desired effect of aeration and water purification is achieved.

Further, the present invention is explained with reference to the drawings, where

figure 1 shows a flotation aerator with the location of the upper surface of the body below the water level;

figure 2 shows a flotation aerator with the location of the upper surface of the body above the water level.

The flotation aerator comprises a housing; a sealed electric motor 1 mounted on the upper surface of the housing and comprising a shaft 4; duct 7; two impellers 5 and 6 mounted on the shaft 4 of the electric motor 1; intake of intake water, and withdrawal of the air-water mixture.

The housing is divided by a removable control diaphragm 10 into two zones - the upper zone 2, in which air is sucked in, and the lower zone 3, in which dispersion occurs. An electric motor shaft 4 with two impellers is located inside the casing, while the impeller 5 located in the upper zone 2 is made with helical blades, and the second impeller 6 is located in the lower zone 3, and is made in the form of a rotor with vertically arranged interchangeable blades, having various configurations, for example rectangular and perforated and / or serrated blades. The air duct 7 is connected to the upper zone 2 and contains a control device 8 located in its upper part above the water level. The upper surface of the housing may be located below the water level (figure 1). It is possible that the electric motor 1 is located on the upper surface of the casing located above the water level (Fig. 2), in this embodiment, the height of the upper zone 2 is determined by the necessary depth of immersion of the aerator, and the electric motor is leaky.

The outlet of the water-air mixture is made in the form of perforation in the side walls of the lower zone 3, while the perforation is made with a predetermined number and diameter of holes, ensuring the formation of the finely dispersed mixture necessary for flotation and its uniform and dispersed release. The distance between the outer edges of the blades of the impeller 6 and the perforated wall of the lower zone 3 is 5-10 mm, depending on the configuration of the blades. Perforation was made with a given number of holes having a diameter of 3-20 mm, and the larger the size of the dispersion zone (diameter and height), the larger the diameter of the holes. Reducing or increasing the diameter of the holes is not effective for the dispersion process itself. The holes are evenly staggered. The perforation area is 20-60% of the area of the side walls of the lower zone 3, and going beyond the boundaries of the specified range reduces the efficiency of the process. In addition, perforation of the area of the side walls of more than 60% reduces the strength of the housing in the lower zone 2.

The water inlet is made in the form of holes in the lower part of the lower zone 3, to the flange of which nozzles 11 are attached, and contains a regulating device 9 that controls the intake of sucked water and contains a guide diaphragm 12 with a central hole.

Flotation aerator works as follows:

When the motor shaft rotates, air (gas) is sucked by the impeller 5 into the upper zone 2 through the air duct 7 through the regulating device 8 located in its upper part, and then flows through the regulating diaphragm 10 into the lower zone 3 to the impeller 6. Water enters the lower zone 3 to the impeller b through nozzles 11 and an adjusting device 9, containing a guide diaphragm 12 with a central hole, and located in the lower part of the lower zone 3. When the impeller b rotates in the lower zone 3, air disperses (gas a) into water. The water-air (water-gas) mixture leaves the lower zone 3 through the lateral perforated walls. The regulation of the quality of the water-air (water-gas) mixture, namely the number and size of bubbles, is carried out by changing the ratio of water and air (gas) in the mixture using control devices 8 and 9, as well as by changing the number of revolutions of the electric motor. The diameter of the opening of the regulating diaphragm 10, located between the impellers 5 and 6, and dividing the housing into the upper zone 2 and lower zone 3, is set depending on the operating conditions of the aerator, namely, on the depth of its immersion.

Thus, the proposed design of the flotation aerator allows to increase the efficiency of preparation of finely dispersed air-water mixture and increase the reliability of the aerator.

Claims (9)

1. Flotation aerator containing a housing containing a partition with a Central hole, dividing its space into upper and lower zones; water inlet located in the lower part of the lower zone; air duct the conclusion of the water-air mixture; an electric motor with impellers mounted on its shaft, located in various zones of the housing, characterized in that the partition is made in the form of a diaphragm with a central hole, the duct is connected to the upper zone, and the outlet of the air-water mixture is made in the form of perforation in the side walls of the lower zone of the housing; the impeller located in the lower zone is made in the form of a rotor with vertical interchangeable blades made perforated and / or with serrated edges; water is introduced into the lower zone with the possibility of its entry through a removable control diaphragm with a central hole and nozzles; the electric motor is completely in the volume of aerated water. 2. The flotation aerator according to claim 1, characterized in that the duct contains a control device for controlling the air supply, located in its upper part and above the water level, the electric motor contains a speed controller for the shaft speed, and the water inlet contains a control device for controlling the water supply, containing a guide diaphragm with a Central hole, and nozzles attached to the lower part of the lower zone. 3. The flotation aerator according to claim 1, characterized in that the electric motor is mounted on the upper surface of the housing. 4. Flotation aerator according to claim 3, characterized in that the upper surface is located below the water level. 5. The flotation aerator according to claim 1, characterized in that the diaphragm is removable and may have a different diameter of the Central hole, the size of which is set depending on the depth of immersion. 6. The flotation aerator according to claim 1, characterized in that the impeller blades are made in a rectangular shape. 7. The flotation aerator according to claim 1, characterized in that the perforation in the lower zone of the housing is made with a given frequency and diameter of the holes. 8. The flotation aerator according to claim 1, characterized in that the impeller located in the upper zone of the housing is made in the form of a wheel with helical blades. 9. The flotation aerator according to claim 1, characterized in that the gap between the outer edge of the impeller vanes and the perforated wall is 5-10 mm.

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