RU2396216C1 - Device for water disinfection - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to devices for cavitation-based disinfection of natural and sewage waters without application of chemical reagents and can be applied in systems of household-drinking and industrial water supply, as well as for disinfection of sewage of enterprises of meat and diary industries. Device includes body in which installed is bush with 8 longitudinal canals with placed in them swirling devices in form of screw helical flow generators, which ensure swirling, acceleration of flows and their cavitation. On canal output placed is acoustic pulse chamber, in which in case of interaction of cavitating flows fluctuating with the same frequency, acoustic resonant excitation appears.

EFFECT: increase of efficiency of water disinfection device due to acoustic resonant excitation of cavitating flows.

1 dwg

Description

The invention relates to a device for cavitation disinfection of natural and wastewater without the use of chemicals, such as chlorine, fluorine, ozone, and may find application in the preparation of water in drinking water and industrial systems, as well as for disinfecting sewage from enterprises in meat and dairy industry and other agricultural facilities.

There is a method of treating water and aqueous solutions (Russian patent No. 2240984, C02F 1/66, dated November 27, 2004), which includes adjusting the pH of the water by repeatedly decreasing the pressure of a high-pressure liquid during its recirculation to the value at which its cavitation occurs, followed by an increase in pressure to the extent that cavitation ceases. In this case, the recirculated liquid is preheated, after which part of the high-pressure liquid is taken for filtration. A cavitated liquid with increasing pressure is taken from the remaining recirculation stream. Next, the liquid is cooled, kept until the cavitation bubbles collapse and solid impurities precipitate, and then the stabilized liquid is returned to the low-pressure recirculation stream. The known patent also describes the device used. To enhance the cavitation process created by a Venturi nozzle or in the center of a rounded liquid flow, it can be amplified by ultrasound or electric plasma discharge.

The disadvantages of the known solutions are:

a) the selection of hot water for domestic needs or to feed the swimming pool is done before the cavitator, which means that the water is simply heated and passed through the filter without cavitation disinfection;

b) the need to preheat the source fluid to 90 ° C, which is associated with high energy consumption;

c) the use of a Venturi nozzle or a swirling flow as a cavitator with the formation of a reduced pressure zone in the center requires multiple passes of the fluid through the cavitator;

d) the use as an additional means of influencing microorganisms with ultrasound or an electric plasma discharge, which sharply increases the specific energy consumption for disinfection of 1 m ^{3 of} liquid, requires complex hardware design and compliance with unprecedented safety measures.

These shortcomings are eliminated in the "Technological line for the disinfection of wastewater and natural waters" according to Russian patent No. 2328450, C02F 1/36, dated 10.07.2007. The known system contains devices for disinfecting water, each of which includes a cavitator connected to the pump with twisting devices placed in the housing with the possibility of creating cavitation.

A disadvantage of the known device is that it does not use the resonant excitation of cavitating flows.

The problem to which the invention is directed, is to create a device for disinfecting wastewater and natural waters with increased efficiency in the destruction of viruses, protozoa cysts, giardia and helminth eggs by hydrodynamic cavitation without the use of other sources and methods of influencing pathogenic microflora.

The technical result of the claimed invention is to increase the efficiency of the device for disinfecting water due to the acoustic resonant excitation of cavitating flows.

This is achieved by the fact that in the device for disinfecting water, including a cavitator connected to the pump with twisting devices placed in the body with the possibility of creating cavitation, a sleeve with eight longitudinal channels with screw devices placed in them in the form of screws (screw flow formers) is installed in its body ), providing swirling and acceleration of flows, and at the exit from the channels it is placed with the possibility of occurrence of cavitating flows during interaction, oscillating with the same frequency one acoustical resonance excitation of acoustic (pulsation) camera.

It is known that cavitation is the phenomenon of vaporization and air release due to a decrease in pressure in the liquid. The reason for its occurrence is the boiling of a liquid at normal temperature and low pressure. The appearance of cavitation is facilitated by air dissolved in water, which is released when pressure decreases (I. Pirsol. “Cavitation”, p. 9).

In the life of a cavitation bubble, two phases are distinguished - expansion and collapse, which together form a complete thermodynamic cycle.

In the pressure zone, the hydrostatic pressure decreases to such an extent that the forces acting on the liquid molecules become greater than the forces of molecular bonds. As a result of a sharp change in hydrostatic equilibrium, the liquid, as it were, bursts, creating numerous tiny bubbles. Cavitation occurs the earlier, the more the liquid is “contaminated” with solid particles or other foreign bodies (for example, bacteria), the higher its temperature or the more gases dissolved in it. Cavitational "boiling" of the liquid is due to the fact that a thin layer of air is adsorbed on the surfaces of these particles, the particles of which, when they enter the zone of reduced pressure, serve as foci that contribute to the occurrence of cavitation.

Bacterial flora located in the treated fluid also serves as centers for the formation of cavitation bubbles. When liquid enters the zone of reduced pressure, the liquid boils, and in bacteria located in the center or near the formed cavitation bubble, the cell membrane completely or partially breaks down under the influence of the pressure difference inside them and the surrounding space.

The second phase of the life of the acknowledgment bubble - collapse (condensation), occurs in the zone of high pressure, where it moves together with the processed fluid. The condensation process of the cavitation bubble occurs almost instantly. Particles of fluid surrounding the bubble move to its center with great speed. As a result, the kinetic energy of the contained particles causes local hydraulic micropumps at the moment of bubble closure, accompanied by a local increase in pressure to 10 ⁴ kg / cm ² and a local temperature increase to 1000-1500 ° C. Under conditions of flow of hydrodynamic cavitation at high speeds of the working bodies inside cavitators of 28-33 m / s, most of the cavitation bubbles are deformed and have an elliptical or conical shape. When such bubbles collapse, high-energy cumulative streams appear that destroy everything that comes in their way. The collapse of a separate cavitation bubble does not give the expected effect, but there are many cavitation bubbles and “grab” them many thousands per second, therefore, together they can have a significant destructive or other effect without high-temperature heating of the treated fluid.

Thus, in addition to the mechanical effect, cavitation has a bacterial flora and microsterilization effect under ultrahigh-temperature conditions in the region where the cavitation bubble disappears.

The walls of the cavitation bubble and liquid droplets inside it are charged with unlike electricity. When the bubbles are compressed, their sizes sharply decrease and the charges are located on the surfaces of the bubbles of very small sizes. As a result of a sharp decrease in the surface of cavitation bubbles, the voltage of static electricity increases sharply. Between the walls of cavitation bubbles and droplets inside them, electric discharges resembling microscopic lightning slip through. These high-voltage electric discharges also have a detrimental effect on bacteria, which turned out to be the source of the appearance of these bubbles.

High temperatures and pressures arising at the points of disappearance of cavitation bubbles, as well as micromagnets of static electricity, contribute to the decomposition of water through the reactions:

H ₂ O ^↔ H ⁺ + (OH) ^-

2H ₂ O ^↔ (OH) ⁺ + H ₂

hydroxyl groups (OH) ⁺ and (OH) ^- , emitted on the shells of cavitation bubbles, upon condensation of the latter form hydrogen peroxide by the reactions:

(OH) ⁺ + (OH) ^{- →} H ₂ O ₂

2 (OH) ^{- →} H ₂ O ₂ + 2e ^-

The occurrence of cavitation on the surfaces of bacteria surrounded by adsorbed air is accompanied by the formation of free radicals OH ^- , HO ₂ , N, as well as the final products of their recombination H ₂ O ₂ , HNO ₂ , HNO ₃ .

The formation of hydrogen peroxide of free radicals and acids also has a detrimental effect on the bacterial flora of the treated fluid.

The invention is illustrated by the drawing, which shows the design of a device for disinfecting water, on which:

1 - cavitator body;

2 - sleeve;

3 - screw flow former;

4 - holder;

5 - fastener (screw);

6 - acoustic pulsation chamber.

The liquid (water) under pressure P1 is supplied to the sleeve 2 with eight longitudinal channels with eight screw flow formers 3 respectively located in them with a speed of V1. Pressure P1 and speed V1 are provided by a pump (not shown). P1 is selected experimentally (by selection) and is 3.2 atm (the cavitation process begins with a pressure of 3 atm). Next, the liquid (water) envelopes the holder 4, enters the longitudinal channels of the screw flow formers 3, where the formation of vortex (swirling) fluid flows and the acceleration of their movement due to the narrowing of the diameter of the screw flow formers in comparison with the input diameter of the sleeve 2. In the channels of the screw formers flow pressure P1 is greater than P2, flow rate V2 is much greater than V1. At the exit of the channels there is an acoustic (pulsation) chamber 6. As a result, cavitating flows are combined in the acoustic chamber 6 with the possibility of acoustic resonant excitation. In the interaction of cavitating flows oscillating with the same frequency, acoustic resonant excitation occurs.

Thus, due to the acoustic resonant excitation of cavitating flows, an increase in the efficiency of the device for disinfecting water is provided.

Claims (1)

A device for disinfecting water, including a cavitator connected to the pump with swirling devices placed in the housing with the possibility of creating cavitation, characterized in that a sleeve with 8 longitudinal channels is installed in the housing with swirling devices arranged in them in the form of screw flow formers providing twisting and acceleration of flows, and at the exit from the channels there is an acoustic pulsation chamber with the possibility of acoustic resonance excitation during interaction cavitating flows oscillating with the same frequency.

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