RU2315848C2 - Method and device for hydraulic cavitational scale and deposit erosion, as well as rock breakage in water - Google Patents

Abstract

FIELD: construction and geology, particularly to break natural and artificial scale and deposits and to drill holes.

SUBSTANCE: method involves supplying water under pressure at hydraulic cavitational device inlet; activating hydraulic cavitational process in the device with the use of cavitational body located inside the device; directing cavitation water jet from device outlet to surface to be eroded. Pressure of 90-200 atm is provided at device inlet. Space in front of surface to be broken is filled with water for height of at least 300 mm of water column. Distance between device outlet section and surface to be broken is 20-1500 mm. Hydraulic cavitational process has maximal power to provide vibratory super-cavitation with local medium heating, water ionization and cavitational erosion of surface to be broken. This is provided by two ways of water jet direction inside the device. In the first case water jet is directed through two-step chambers having different cross-sections. In the second case water jet passes trough hollow cavitational body made as contraction tube secured inside the chamber. Both water jets are mixed with each other at device outlet. Vibratory super-cavitation presence is detected. Device comprises hollow body with opposite opened ends, cavitational body secured in the body so that the cavitational body extends in longitudinal body direction, and hollow nozzle. Body interior is made as two-step cylindrical chamber. The first step is inlet step and has diameter not exceeding 0.5 of that of the second step. Cavitational body is hollow contraction tube having wavy surface and tapering in water jet direction from device inlet. Ratio between the smallest nozzle and contraction tube diameters is 1.25-2.0.

EFFECT: increased cavitational jet power.

5 cl, 4 dwg

Description

The method and device relate to the fields of geology, production, energy and construction and can be used in technologies for the destruction of natural and artificial growths and deposits, as well as in technologies for drilling wells, etc.

The known method and device used for grinding fibrous impurities in suspensions by activating the cavitation process in them (patent No. 2134611 for the invention "Cavitation mixer" according to IPC 6 B01F 5/00, Bull. No. 23 from 08.20.1999).

The method includes supplying pressure and pressure to the inlet of the cavitation mixer of the suspension and steam and activating the cavitation process inside it.

The device comprises a housing and a cavitation body (in a known device, a cavitator).

The known method and device are focused on the use of cavitation for grinding fibers and impurities in the food industry and cannot be used without additional invention in the destruction of natural and artificial barriers.

Closest to the claimed invention are the method and device described in the invention "Method of cavitating liquid stream" (patent No. 2060344 for IPC 6 ЕВВ 7/18, Bull. No. 14 from 05/20/1996).

The known method includes supplying pressure to a cavitation device for steam, activating a cavitation process in this device and ejecting a cavitating jet of water onto the surface to be treated.

The known device comprises a hollow body open on two sides and a cavitation body (in the known device, a central body), mounted inside the body.

The known method and device also cannot be effectively used to destroy natural and artificial obstacles, because focused on microscopic surface treatment, do not allow the development of a powerful cavitation process and do not contain sufficient information about the geometric and other characteristics of the cavitation body and the inner chamber of the body, which would allow for powerful cavitation.

The purpose of the claimed method and device is to eliminate the above drawbacks, more precisely, to obtain the maximum power of the cavitation water jet by optimizing the geometric shape and ratios of individual parts of the cavitation body and the device body, which, ultimately, allows the destruction of solid surfaces at relatively low energy costs.

This goal is achieved by the fact that the method of hydrocavitational erosion destruction of growths and deposits, as well as rocks in the aquatic environment, comprising supplying pressurized water to the inlet of the hydrocavitation device, activating the hydrocavitation process inside the device using the cavitation body located there, and directing the cavitating water stream with the exit of this device to the destructible surface, characterized in that at the inlet of the device provide pressure from 90 to 200 atmospheres, at the initial stage significantly fill the space in front of the destructible surface with water from a height of 300 mm water column, then the distance from the exit section of the device to the destructible surface is provided in the range of 20 to 1500 mm, and a hydrocavitation process of maximum power is formed, which is vibrational supercavitation with local heating of the medium, ionization water and cavitation erosion of the destructible surface, which provides due to the artificial formation of forced oscillations of the water flow, for which its inside the hydro-cavitation device in two different ways, the first through a two-stage chamber with different cross sections of these steps, and the second through a hollow cavitation body in the form of a confuser, fixed in this chamber, then both of these water jets are mixed in a nozzle at the outlet of the device, the existence of vibrational supercavitation is determined according to the formula:

(Pn / Po) · (lo / do) ≤0.8,

where: Pn / Po is the cavitation number, defined as the ratio of the hydrostatic pressure around the flowing water stream to the destructible surface (Pn) to the total pressure at the outlet of the hydro-cavitation device (Po);

lo is the distance from the exit slice of the device to the fracture surface;

do - the smallest cross-sectional diameter of the hydro-cavitation device.

The device of hydrocavitation erosion destruction of growths and deposits, as well as rocks in the aquatic environment, containing a hollow body open on both sides and a cavitation body fixed longitudinally in the center, additionally contains a hollow nozzle, the body inside is a two-stage cylindrical chamber, in which the diameter of the first the stage, which is the input of the device, is equal to 0.5 of the diameter of the second stage or less, and the cavitation body is a hollow confuser with a narrowing of its channel and external shape with shaped surface in the direction of the jet from the device inlet, the nozzle being removable and screwed into the second stage of the housing with its smaller diameter, penetrating into it half its length, and forming the device exit with its outer cut, the shank of the cavitation body starts at the device inlet, and its the tip slightly goes into the nozzle, while the ratio of the smallest diameters of the nozzle and confuser is 1.25-2.0.

The technical result of the claimed method and device consists in increasing the power of the cavitation jet by 2–3 times, and, as a result, in significantly reducing the cost of achieving the goal, due to the reduction in the required hydraulic pressure to 90–200 atmospheres instead of 500–1000 atmospheres with weak cavitation.

Figures 1, 2, 3 and 4 respectively show sketches of a hydro-cavitation erosion device with a removable nozzle in the form of a diffuser, a removable nozzle in the form of a confuser, a removable nozzle in the form of a chisel and a hand-held device with a nozzle in the form of a confuser.

The device comprises a housing 1 with a first stage 2 and a second stage 3, a cavitation body 4 with a shank 5, a tip 6, a wavy surface 7 and a channel 8, a removable nozzle 9 in the form of a diffuser with the smallest diameter 10, extension 11 and thread 12, sleeve 13 for water supply with an articulating connector 14 and a locking mechanism 15.

For clarification, the optimum distance 16 to the destructible barrier 17 is also shown.

Mounting, for example, using the spokes of the cavitation body 4 inside the housing 1 is not shown due to the non-principle of this within the framework of the claimed technical solution. For the same reason, the guiding and holding means orienting the device in space are not shown.

The diameter of the first stage 2 of the chamber 1 is equal to 0.5 of the diameter of the second stage 3, and the cavitation body 4 is a hollow confuser with a narrowing of its channel 8 and a wavy surface 7 in the direction of the jet. The ratio of the smallest diameters of the diffuser 9 and confuser 4 (respectively 10 and 6 is the diameter of the tip) is 1.25-2.0.

The method is as follows.

Let the manual hydro-cavitation device is articulated through the connector 14 with the sleeve 13 for supplying water (figure 1). At the entrance of this device serves water under a pressure of 90-200 atmospheres through the sleeve 13, opening the locking mechanism 15.

If the destructible surface 17 is not in water, then the operator holding the hydro-cavitation device at the initial stage artificially fills the space in front of the surface 17, first moving the edge of the diffuser 9 almost close to this surface, and then sets the optimal distance 16 within 20-1500 mm, which is determined during operation with the most intense erosion of the destructible surface 17.

The hydrocavitation process develops due to the fact that the water inside the device is sent in two different ways: through the first 2 and second 3 stages of the housing 1 and through the channel 8 of the cavitation body 4, tapering from the shank 5 to the tip 6, and then both jets of water are mixed near the tip 6 in the zone of smallest diameter 10 of the diffuser 9, where a cavity is formed - a region of sharply increased water pressure. Vibrational supercavitation occurs with local heating of the medium and ionization of water. At the same time, the number of vapor bubbles carried away from the diffuser 9 by a vibrating stream to the surface 17, on which cavitation erosion occurs — the destruction of a solid substance — is rapidly growing in the cavity.

The authors experimentally established that the existence of vibrational supercavitation is determined according to the formula:

(Pn / Po) · (lo / do) ≤0.8.

where: Pn / Po is the cavitation number, defined as the ratio of the hydrostatic pressure around the flowing water stream to the destructible surface (Pn) to the total pressure at the outlet of the hydro-cavitation device (Po);

lo is the distance from the exit slice of the device to the fracture surface;

do - the smallest cross-sectional diameter of the hydro-cavitation device.

The maximum intensity of vibrational cavitation erosive destruction of the surface is determined from the formula:

ΔG / Δτ = const · Pn / Po- [const-1/2 (lo / do) ² ] ^exp ,

where ΔG is erosion wear

Δτ is the duration of erosion wear.

Maintain the maximum value of the jet stream at the outlet of the hydro-cavitation device (Fmax) according to the formula:

Fmax = 200 · S · ρ · (Po-Pn) · k · sinγ,

Where:

S is the cross-sectional area of the jet stream at the outlet of the hydro-cavitation device,

ρ is the density of water,

γ is the angle of inclination of the flowing jet stream to destructible surface,

k is the experimental coefficient, depending on the characteristics of the destructible surface and other parameters associated with the working area near the destructible surface.

The device operates as follows.

Above, simultaneously with the description of the implementation of the method, the operation of a manual hydro-cavitation device using a nozzle 9 in the form of a diffuser was considered (Fig. 1). In this case, before starting work, the diffuser nozzle 9 was screwed into the housing 1 in order to use it outside the aqueous medium for its artificial formation. This nozzle is also more effective when working, including in the aquatic environment, with soft materials (limestone, etc.), because destroys a wider area at the same time.

To destroy hard surfaces (stones, etc.) as a nozzle 9 use a confuser (figure 2), which is screwed before work into the housing 1.

For the destruction of particularly hard surfaces (concrete, etc.), if necessary, additional impacts as a nozzle 9 use a bit with a hole for outputting a cavitation jet (figure 2), which is screwed before work into the housing 1.

Claims (5)

1. A method of hydrocavitational erosion destruction of growths and deposits, as well as rocks in an aqueous medium, comprising supplying pressurized water to the inlet of a hydrocavitation device, activating a hydrocavitation process inside the device using a cavitation body located there, and directing a cavitating water stream from the outlet of this device to destructible surface, characterized in that at the inlet of the device provide pressure from 90 to 200 atmospheres, at the initial stage, the spaces are artificially filled with water about in front of the destructible surface to a height of 300 mm water column, then the distance from the exit slice of the device to the destructible surface is provided in the range from 20 to 1500 mm, whereby the hydrocavitation process is formed with maximum power and is a vibrational supercavitation with local heating of the medium, water ionization and cavitation erosion of the destructible surface, which is ensured by the artificial formation of forced oscillations of the water flow, for which it is directed inside the hydrocavitation unit three different ways, the first through two-stage chambers with different cross sections of these steps, and the second through a hollow cavitation body in the shape of a confuser, fixed in this chamber, then both of these water jets are mixed in a nozzle at the output of the device, while the existence of vibrational supercavitation determined according to the formula (Pn / Po) · (lo / do) ≤0.8, where Pn / Po is the cavitation number, defined as the ratio of the hydrostatic pressure around the flowing water jet to the destructible surface (Pn) to the total pressure at the outlet of the hydro-cavitation device (Po); lo is the distance from the exit slice of the device to the fracture surface; do - the smallest cross-sectional diameter of the hydro-cavitation device. 2. A device for hydrocavitational erosion destruction of growths and deposits, as well as rock in an aqueous medium, comprising a hollow body open on both sides and a cavitation body fixed longitudinally in the center, characterized in that the device further comprises a hollow nozzle, the body inside is a two-stage cylindrical chamber, in which the diameter of the first stage, which is the input of the device, is equal to 0.5 or less than the diameter of the second stage, and the cavitation body is a hollow confuser with narrower the lower part of its channel and external shape with a wavy surface in the direction of the jet from the device inlet, the nozzle being removable and screwed into the second stage of the housing with its smaller diameter, penetrating into it half its length, and forming the device exit, the cavitation body shank with its external cut begins at the inlet of the device, and its tip slightly goes into the nozzle, while the ratio of the smallest diameters of the nozzle and confuser is 1.25-2.0. 3. The device according to claim 2, characterized in that the removable nozzle is a diffuser with the expansion outward. 4. The device according to claim 2, characterized in that the removable nozzle is a confuser with a narrowing outward. 5. The device according to claim 2, characterized in that it is a hand-held device with a handle.

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