Device and Method for Hydrodynamic Surface Cleaning Based on Micro-Hydropercussion Effect

Abstract

A nozzle for hydrodynamic cleaning has a form form of a flow passage with a profile formed by an inlet confuser, a resonance chamber and a diffuser arranged in axial alignment and interconnected in series. The confuser and the diffuser are connected via the resonance chamber, which has a form of a flow-over lip. The ratio of the cross-sectional area at the confuser outlet and the cross-sectional area at the opening of the resonance chamber forming the flow-over lip is 1.5 to 10.0. The preferred ratio of the resonance chamber surface area and the cross-sectional area at the opening of the resonance chamber is 0.05 to 40.0. The diffuser can comprise means for additional supply of fluid, gas or particulates. Impact is performed through a fluid jet flowing from a nozzle of the working member in a fluid or a gaseous medium.

Claims

1. A nozzle for hydrodynamic cleaning comprising: a flow passage with a profile formed by an inlet confuser, a resonance chamber and a diffuser arranged in axial alignment and interconnected in series, the confuser and the diffuser being connected via the resonance chamber, the resonance chamber being in a form of a flow-over lip, wherein a ratio of a cross-sectional area at an outlet of the confuser and a cross-sectional area at an opening of the resonance chamber forming the flow-over lip ranges from 1.5 to 10.0.

2. The nozzle for hydrodynamic cleaning according to claim 1, wherein a ratio of a surface area of the resonance chamber and a cross-sectional area at the opening of the resonance chamber ranges from 0.05 to 40.0.

3. The nozzle for hydrodynamic cleaning according to claim 1, the diffuser comprises means for additionally supplying fluid, gas or particulates.

4. The nozzle for hydrodynamic cleaning according to claim 1, wherein the confuser has a conical shape.

5. The nozzle for hydrodynamic cleaning according to claim 4, wherein the confuser has a taper angle of 10-20.

6. The nozzle for hydrodynamic cleaning according to claim 1, wherein the diffuser has a conical shape.

7. The nozzle for hydrodynamic cleaning according to claim 6, wherein the diffuser has a taper angle of 15-70.

8. A method of hydrodynamic cleaning comprising: impacting a surface to be cleaned by a fluid jet under pressure, the fluid jet flowing from a nozzle of a working member in a fluid or gaseous medium, the impacting being performed by means of the nozzle for hydrodynamic cleaning comprising: a flow passage with a profile formed by an inlet confuser, a resonance chamber and a diffuser arranged in axial alignment and interconnected in series, the confuser and the diffuser being connected via the resonance chamber, the resonance chamber being in a form of a flow-over lip, wherein a ratio of a cross-sectional area at an outlet of the confuser and a cross-sectional area at an opening of the resonance chamber forming the flow-over lip ranges from 1.5 to 10.0.

9. The method of hydrodynamic cleaning according to claim 8, wherein the fluid jet flows at an angle of 5 to 90 to the surface to be cleaned.

10. The method of hydrodynamic cleaning according to claim 8, wherein the fluid jet flows at a distance of 5 to 1000 mm to the surface to be cleaned.

11. A method according to claim 8, further comprising evaluating cleaning efficiency by a vibration intensity of the nozzle.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0033] FIG. 1 depicts a cross-section of a nozzle for hydrodynamic cleaning; and

[0034] FIG. 2 is a schematic illustration of operation of a device.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0035] Design Description of Nozzle

[0036] FIG. 1 depicts a nozzle for hydrodynamic cleaning, wherein 1 depicts an inlet confuser, 2 depicts a resonance chamber, which has a form of a flow-over lip, 3 depicts a diffuser, D refers to the outlet diameter of the confuser, d refers to the diameter of the cross-sectional opening of the resonance chamber, L refers to the resonance chamber length, a and b refer to the taper angles of the confuser and the diffuser. FIG. 2 depicts e device operation circuit, wherein supplied fluid (1), nozzle of the working member (2), fluid jet (3), slope angle (4) to the surface to be cleaned (5), distance from the device to the surface to be cleaned (6).

[0037] A nozzle for hydrodynamic cleaning is in the form of a flow passage with a profile formed by an inlet confuser (1), a resonance chamber (2) and a diffuser (3) arranged in axial alignment and interconnected in series. The resonance chamber has a form of a flow-over lip, wherein the ratio of the cross-sectional area at the confuser (D) outlet and the cross-sectional area at the opening of the resonance chamber (d) forming the flow-over lip is 1.5 to 10.

[0038] The ratio of the resonance chamber surface area and the cross-sectional area at the opening of the resonance chamber is preferably 0.05 to 40.0.

[0039] The diffuser can comprise means for additional supply of fluid, gas or particulates.

[0040] The confuser has most preferably a conical shape with a taper angle of 10-20 (a)

[0041] The diffuser has most preferably a conical shape with a taper angle of 15-70 (b).

[0042] These parameters have been obtained out of the hundreds of experiments followed by their subsequent processing to find and describe the consistency patterns.

[0043] As a result, the nozzle is composed of a water jet acceleration area, a water cavitation area and a cavitating jet expansion area. The acceleration area accelerates the water jet, its primary function is to straighten and stabilize the water flow by its limited acceleration before entering the cavitation area. The cavitation area is formed by a resonance chamber having a form of a flow-over lip. The formed bubbles shall on the one hand be intensive enough to have sufficient cleaning effect when impacting the surface, however, they are not to be too intensive not to lock the acceleration passage, as the degrading jet manifests itself as a simple flow of bubbling foam, which intensively decelerates resulting in the formed bubbles being imploded immediately after exiting the acceleration passage, so a cleaning effect will not be achieved.

[0044] The expansion area has the function to stabilize the cavitating jet. When exiting the acceleration passage, an expansion area is being formed with a low-pressure area respectively, which prevent degrading of jet; formulated differently, thanks to the outlet cone, a divergent cone is formed instead of a narrow high-pressure water flow. As a result, a sufficiently wide spot is generated, as the cavitating jet impact the surface to be cleaned. The micro-hydro percussion in this spot generates backward impact through the water jet and transfers vibration to the working tool; based on the vibration behavior, the intensity of impact to the surface to be cleaned can be evaluated. The micro-hydro percussion impact as a backward impact to evaluate the cavitation intensity is a differentiator. While other cavitation intensity evaluation methods are based on measuring the surface destruction rate, the claimed method is based on measuring the jet perturbation caused by micro-hydro percussion in the form of backward impact.

[0045] Cleaning Method Implementation

[0046] To perform hydrodynamic cleaning in the fluid or gaseous medium, the surface to be cleaned is to be impacted by a fluid jet under pressure. Fluid (1) is supplied, fluid is flowing from a nozzle of the working member (2). The fluid jet (3) most preferably flows at an angle of 5 to 90 (4) to the cleaned surface (5), most preferably at a distance of 5 to 1000 mm from the device to the surface to be cleaned (6). Cleaning efficiency can be evaluated by vibration intensity of the nozzle. A combination of the jet angle and the distance from the nozzle to the surface to be cleaned is defined by intensity of the micro-hydro percussion impact, which is perceived on side of the nozzle as sufficiently intensive vibration that can be personally perceived as more intensive/less intensive, if the device is operated manually, or by a dedicated strain-gauge sensor, if the device is mounted on a holding tool. Consequently, by changing the angle and the distance, the maximum cleaning intensity can be defined by the maximum micro-hydro percussion.

EMBODIMENT 1

Cleaning of Tubes from Industrial Impurities (Concrete),

[0047] Problem: Cleaning the drill rods of the drilling mud (concrete blend with additives). The distinction of the impurity is that the drilling rod having the form of a tube is entirely, from end to end, clogged by the drilling mud, wherein the blend is of very high quality, therefore it is difficult to clean the resulting mass. Cleaning with the application of the micro-hydro percussion impact is performed in the following sequence: [0048] a device using the micro-hydro percussion impact is mounted onto a dedicated holding tool, representing a thin steel 5 m long tube, [0049] the dedicated holding tool is connected to a high-pressure hose, section 0.25, connected to a pumping unit, [0050] the pumping unit with parameters 500 atmospheres, 40 L/min, activated by a self-contained diesel plant and connected to an industrial water pipeline, [0051] when evaluating efficiency of various methods, the first cleaning is performed by using a nozzle in form of a simple high-pressure atomizer used in car wash service, etc. As consequence, the tube is cleaned extremely slowly, and the evaluation has to be terminated because of a failure to make any further progress, and the internal deposits of hardened concrete cannot be cleaned. [0052] subsequent cleaning is performed using a manual device with a nozzle according to the claimed invention, with a ratio of the cross-sectional area at the confuser and the cross-sectional area at the opening of the resonance chamber being 2.76; with a ratio of the resonance chamber surface area and the cross-sectional area at the opening of the resonance chamber being 2.11; a taper angle of the confuser being 1428, a taper angle of the diffuser being 34. The complete cleaning of the part takes 20 minutes, wherein the internal deposits of hardened concrete are removed completely. The comparison results are registered by photo and video recording.

EMBODIMENT 2

Cleaning of the Internal Surface of the Tube from Industrial Impurities (Chemical Scaling)

[0053] Problem: Cleaning of the internal surface of a heat exchanger of impurity by scaling of bitumen (chemical production). As the heat exchanger operates, the internal surface of the tubes with circulating bitumen is exposed to scaling due to high temperatures, this decreases the capacity of the heat exchanger. To solve the problem, the equipment is shut down at regular intervals and is partially dismantled to perform its cleaning. The distinction of the problem solution is that extremely tight cleaning terms are set, as the downtime of the plant results in severe losses. Therefore, performance of the cleaning equipment is critical. The internal surface of the heat exchangers are usually cleaned by ultra-high pressure apparatus (1000 atmosphere) using a water jet and milling cutters, wherein water jet cleaning takes substantial time due to low performance and incomplete cleaning of the surface. The remaining mechanical impurities are removed by the milling cutters, which causes wear and tear of the heat exchangers surfaces increasing the probability of their failure before their scheduled service life, which demands extremely high-value repairs. Cleaning with the application of the micro-hydro percussion impact is performed in the following sequence: [0054] the heat exchanger to be cleaned was partially dismantled and located onto a surface, which ensures easy access to the butt-ends (cleaning area), [0055] a device according to the claimed invention, with a ratio of the cross-sectional area at the confuser and the cross-sectional area at the opening of the resonance chamber being 8.97; with a ratio of the resonance chamber surface area and the cross-sectional area at the opening of the resonance chamber being 3.78; a taper angle of the confuser being 20, a taper angle of the diffuser being 36, using the micro-hydro percussion impact, mounted onto a dedicated holding tool represented by a section of a flexible 5 m long plastic pipeline, section 0.25, to enable movement of the heat exchanger tube cleaning device inside the heat exchanger tubes considering line bends and curved sections, [0056] the flexible plastic pipeline is connected to the high-pressure main hose, section 0.25, connected to a pumping unit, [0057] the pumping unit is represented by a mobile pump station with the pump parameters 1000 atmospheres-20 l/min, and supplied with a self-contained diesel engine, and a water treatment system (water heating and filtration unit), connected to an industrial water supply system, [0058] when evaluating efficiency of the method, the tube is cleaned by using a nozzle in form of a simple ultra-high pressure atomizer followed by an attachment inform of a hydro mechanic milling cutter, [0059] subsequent cleaning of the second tube is performed with a nozzle, which uses the micro-hydro percussion impact, no hydro mechanic milling cutter is used, the micro-hydro percussion impact is created at a distance of 100 to 200 mm from the surface, [0060] cleaning during several minutes using a conventional nozzle resulted in incomplete cleaning, the nozzle is to be replaced by a hydro mechanic milling cutter, which does not ensure the complete cleaning of the tube, [0061] cleaning using a nozzle with a micro-hydro percussion impact resulted in complete cleaning of the tube, which took less than 1 minute, no hydro mechanic milling cutter was required, [0062] the cleaning results are evaluated by the water discharge from the opposite end of the cleaned tube: when cleaning using a conventional nozzle, the supplied water starts running out backwards (the nozzle bears against insurmountable clogging), and the use of the hydro mechanic milling cutter shows insufficient water discharge, which means that clogging is surmounted, but cleaning is incomplete; the use of the nozzle with the hydro-micro percussion impact according to the claimed invention shows fast surmounting of clogging and substantial water discharge from the tube, which means its complete cleaning. The comparison results are registered by photo and video recording.

EMBODIMENT 3

Cleaning of a Component

[0063] Problem: Cleaning of a form work joint of an impurity from hardened concrete. When using the form work, concrete fills the joint and hardens. Subsequent use of the joint after dismantling of the form work is not possible without cleaning the joint. Surface cleaning using conventional high-pressure apparatus takes substantial time, complete cleaning of the component is not possible. Cleaning using mechanical methods causes damage to the zinc-plated surface of the component, followed by its corrosion and its state of disrepair. Cleaning with the application of the micro-hydro percussion impact is performed in the following sequence: [0064] the component to be cleaned is fixed and reliably fastened to avoid displacement, in a location not vulnerable to water splash, [0065] device according to the claimed invention, with a ratio of the cross-sectional area at the confuser and the cross-sectional area at the opening of the resonance chamber being 5.49; with a ratio of the resonance chamber surface area and the cross-sectional area at the opening of the resonance chamber being 2.69; with a taper angle of the diffuser being 20, a taper angle of the diffuser being 35, with a distance of the device of 100 to 200 mm from the surface at an angle of 45 to 80 to the surface to he cleaned; the device is mounted onto a manual holder tool represented by tap having a form of a pistol grip, and an extension with a device fastener, [0066] the manual holder tool is connected to the pumping unit by a high-pressure hose, section 0.5, [0067] the pumping unit is represented by a mobile pump station with the pump parameters 170 atmospheres-70 l/min, and supplied with a self-contained diesel engine, and a water tank, volume 1000 l, [0068] when evaluating efficiency of the method, the first cleaning is performed by a manual device having a nozzle as a conventional high-pressure atomizer used in car wash service, etc. [0069] subsequent cleaning is performed using a manual device with a nozzle using the micro-hydro percussion impact at a distance of 100 to 200 mm from the surface, [0070] the pumping unit operation is evaluated using a manometer and water flow measuring in a measuring container (filling of a large 20 l laboratory bottle is measured with the use of the nozzle), [0071] results of the component cleaning after several minutes using a conventional nozzle show that the component is only partially cleaned, wherein the internal deposits of hardened concrete preventing operation of the component are cannot be cleaned, [0072] results of the cleaning using a nozzle, which uses the micro-hydro percussion impact, show the complete cleaning time of 1 minute, wherein internal deposits of hardened concrete are completely removed, and the mobility of the component is reinstated.

[0073] The comparison results are registered by photo and video recording.

[0074] Thus, use of the claimed nozzle, which uses the micro-hydro percussion impact provides for efficient cleaning of surfaces of industrial and natural impurities at lower pressure values and at low costs, including cleaning in the air medium.