SU1680386A1 - Method of cleaning interior surfaces of cylindrical parts - Google Patents

Description

The invention relates to cleaning methods and allows you to improve the quality of cleaning the inner surface of cylindrical products (CI) due to partial filling

The invention relates to methods for cleaning the internal cavities of products from solid insoluble contaminants and can be used in engineering, chemical and other industries.

The aim of the invention is to improve the quality of cleaning the inner surface of hollow cylindrical products and reducing the cost of cleaning, as well as simplifying the cleaning process.

The goal is achieved due to the fact that according to the method of cleaning the inner surface of cylindrical products by partially filling the cavity of the product with a cleaning solution and giving the product vibrations at the frequency of resonant vibrations of the cleaning medium, the product is placed vertically and its cavity is sealed after filling

CI cavity with cleaning solution (MR) and vibration oscillation messages at the frequency of the washing medium resonance. To do this, CI is positioned vertically and, after filling, the MR seals its cavity, in the lower part of which a localized gas volume is placed, which forms a liquid-gas non-linear oscillatory system with MR, and dispersed particles of abrasive material. When QI communicates vertical oscillations with the resonance frequency of the liquid-gas system, the particles of abrasive material under the action of powerful turbulent MR flows make intense chaotic movements in the QI cavity, affecting the inner surface of the QI and contributing to the effective removal of impurities from it. 2 Il.

detergent solution, while in the lower part of the cavity a localized gas volume is placed, which forms a non-linear gas-liquid oscillatory system and dispersed particles of abrasive material with the cleaning solution, and oscillations of the product are reported in the vertical direction at the resonance frequency of the gas-liquid oscillatory system .

FIG. 1 shows the device, a general view; in fig. 2 shows section A-A in FIG. one.

The product to be cleaned 1 is installed in a vertical position with the open end up and rigidly fixed on the working platform 2 of the shaker. The cavity of product 1 is 80-85% filled with detergent solution, the rest is air or other gas, and is sealed, for example, by means of a cover 3 with a seal 4. docked to the open end of the product. AT

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The lower part of the cavity of the product in the liquid is placed elastic gas-filled element 5, which is a gas-filled elastic spherical shell 6. made, for example, from a rubber film. The gas-filled element 5 is freely placed in the liquid and held in the lower part of the cavity of the product at a predetermined level using a horizontal grid 7 fixed on the lower end of the vertical rod 8 mounted along the axis of the product and fixed in the cover 3 with the possibility of vertical movement and fixation of the position. In the lower part of the cavity there is also a layer of dispersed particles of abrasive material 9, for example, an electron of fused corundum with a size of 0.8-1.0 mm. The gas pressure inside the elastic element 5, due to the elastic sheath localizing the gas, is equal to the pressure of the liquid surrounding the gas. At the same time, gas and liquid are constantly in stable dynamic contact with each other - any change in fluid pressure is immediately transmitted to gas, and vice versa. Since the liquid is inertial, and the gas has good elastic properties, in their interaction, they form in the cavity of the product being cleaned a non-linear oscillatory system “gas liquid”, which is highly sensitive.

When the vibrostand is turned on, vertical periodic oscillations of the working platform 2 are excited (with a given frequency and acceleration), which are communicated to the product to be cleaned 1. In this case, a dynamic (variable) pressure is excited in the fluid (washing solution) located in the product cavity, changing with the frequency of external vibration effects. Changes in the fluid pressure through the elastic shell 6 of the elastic element are transmitted to the gas localized in it, causing periodic pulsations of its volume — the pulsations of the gas-liquid oscillatory system and the cavities of the product being cleaned are excited. These pulsations cause turbulization of the volume of fluid in the cavity of the product. However, in the absence of resonance, the dynamic pressure in the liquid and its turbulization are small and the dispersed particles of abrasive material in the liquid are in the lower part of the cavity in a state of rest or weak mixing. It was established experimentally that the natural frequency of a gas-liquid system of this type is equal to

where η is the adiabatic index for gas;

p is the pressure in the cavity above the free

liquid surface, dyne / cm ² ;

5 - the area of the horizontal section of the localized gas, cm ² ;

O is the volume of localized gas in a liquid, cm ³ ;

K is the height of the liquid column above the localized gas, cm;

p is the density of the liquid.

According to this method, the vibration effect on the product is produced with a frequency equal to the natural frequency of the gas-liquid oscillatory system, which provides a resonant mode of pulsations of this system. Under resonance conditions, the intensity of the system pulsations increases dramatically: the amplitude of the volume pulsations of the localized gas increases and is 3-4 times the amplitude of the dynamic pressure waves in the liquid increases, powerful turbulent pulsating flows are created in the liquid and it instantly boils, trapping gas from the top spines, which in the form of a multitude of small bubbles are distributed in the liquid volume.The pressure in the cavity being cleaned rises and a homogeneous hydrosol is formed in it that fills its entire volume, the boundary between the liquid and the gas in the upper part of the cavity disappears. Dispersed particles of abrasive material in the lower part of the cavity captured by powerful turbulent fluid flows and are in it in the form of suspended matter, making very intense chaotic movements.

In this mode, intensive pulsating turbulent flows of liquid (washing solution) affect the surface of the cavity to be cleaned, due to which there is an effective flushing of dirt from the walls of the product. At the same time, dispersed particles suspended in a liquid and performing intensive movements, colliding with the surface being cleaned, have an intense abrasive effect on it, significantly increasing the efficiency of separating contaminants, especially hard to remove.

Since, under resonance conditions, peak values of dynamic pressure in a liquid sharply increase, during negative half-periods, its magnitude decreases to the value of saturated vapor pressure, which leads to the formation of cavitation bubbles in a liquid, which, collapsing

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near the surface to be cleaned, contribute to the effective removal of dirt from it.

The combined effect of these factors provides a very high intensity of removing contaminants from the surface being cleaned.

The cleaning process lasts an average of 0.5-2 minutes. At the end of the cleaning process, the source of oscillations is turned off, the dynamic pressure in the liquid disappears and the turbulent pulsations stop, the gas trapped by the liquid floats to the upper part of the cavity, and the dispersed particles descend. If the inner surface of the products is heavily soiled, the cleaning process can be repeated by pouring fresh cleaning solution into the cavity to be cleaned.

This method due to the simultaneous impact on the surface being cleaned turbulent fluid flows, cavitation and abrasive particles allows to improve the quality of cleaning while reducing its duration.

In addition, the non-linear gas-liquid oscillatory system formed in the product cavity is highly sensitive and therefore the excitation of its resonant oscillations is not associated with large power consumption - the optimum amount of vibration acceleration is 5-7 d. This can significantly reduce energy consumption compared to the known cleaning method In which to excite the resonant mode of circular oscillations of the washing solution, acceleration of 20-40 days is necessary.

The proposed method also makes it possible to significantly simplify the process of cleaning cylindrical products and improve its manufacturability, since the vertical vibration effect on a product is much easier to implement than in an inclined plane, and the values of the main parameters of the method (, p. 5, O, b) are easily set in advance and not change during the cleaning process.

During the experimental testing of this method, the inner surface of hollow cylindrical articles with a diameter of 40-100 mm and a length of 100-300 mm was cleaned. The products were installed in a vertical position on the working platform of the VEDS-100 electrodynamic shaker. The internal cavity of the product at 70-90% was filled with a cleaning solution, the rest - the air, and sealed with a lid. In the lower part of the cavity (on the bottom) there was a layer of abrasive particles of corundum electroplating with a dispersion of 0.8-1.0 mm, the height of the layer was 0.05-0.1 height of the cavity. A gas-filled elastic spherical element made of an elastic rubber film was placed in the lower part of the cavity; diameter

gas-filled elements, depending on the size of the product being cleaned, was 18-35 mm. The resonant mode of pulsations of the washing medium in the cavity of products took place at frequencies of 40-65 Hz with vibration accelerations of 5-7 d. The use of transparent models of cylinders (from plexiglas) showed that the greatest intensity of resonant pulsations of the "gas-liquid" system took place at the initial volume of the upper gas cushion equal to 15-20% of the volume of the cavity being cleaned. In this case, the dynamic pressure was maximum (1 ΙΟΙ 20 kPa) and the activated washing medium in the form of a homogeneous hydrosol filled the entire cavity of the product, and the dispersed particles, being suspended, were evenly distributed in the volume of the hydrosol, performing high-intensity chaotic movements and intensely affecting the internal surface of the product.

When the gas cushion is more than 20% of the volume of the cavity, the relative content of liquid in the cavity and the density of the hydrosol produced decrease, which leads to a decrease in dynamic pressure and a decrease in the intensity of resonant pulsations of the washing medium, especially in the upper part of the cavity. At the same time, with a gas cushion of <15% of the volume of the cavity, the density of the hydrosol increases, the mobility of the fluid decreases, and the rigidity of the gas-liquid oscillatory system increases. It also leads to a decrease in the amplitude of the dynamic pressure waves and a decrease in the intensity of the resonant pulsations of the washing medium and, consequently, to a decrease in the intensity of cleaning the inner surface of the product.

Claims (1)

Claim The method of cleaning the inner surface of cylindrical products, which consists in exposing the surfaces to be cleaned with a cleaning solution and vibrating vibrations to the product, characterized in that, in order to improve the quality of cleaning and reduce energy costs, the product is positioned vertically and its inner cavity is sealed after it is filled to 80-85 % detergent solution, while in the lower part of the internal cavity dispersed particles of abrasive material are placed and above them localized elastic gas volume 1680386 with the cleaning solution, forming a non-linear gas-liquid oscillatory system, and the oscillations of the product are reported in a vertical position on the purity of the resonance of the gas-liquid oscillatory system. Fsh 2