DE102004042984A1 - Pipe cleaning method for e.g. waste water system, involves setting ultrasound into coupling unit by sound-radiating end sections of ultrasonic probe that is moved forward in definite speed and direction by water-radiating concentric nozzle - Google Patents

Abstract

The method involves radiating an ultrasound in a coupling unit (5) by sound-radiating end sections of an ultrasonic probe. The Probe is moved forward in a definite speed and direction using a water-radiating concentric nozzle (9) at rear region centrally floating in a pipe line (6). An ultrasonic energy entering into the coupling area takes a value up to 2000 watts, and has a frequency within a range from 20 to 60 kilohertz.

Description

The The invention relates to a method for cleaning pipes, in particular in drinking and wastewater networks, by ultrasound. It is well known that ultrasound in medicine and technology related to imaging techniques for years Application finds. Its low-energy coupling of some Watts in human medicine up to several kilowatts in technology always takes place via a liquid Coupling medium; for the investigation of solid materials or material compounds mostly water is used. The result of his reflection becomes subsequently recorded and analog or digitalized by means of peripheral evaluation elements edited and made visible or reproducibly documented. The physical processes in the coupling medium itself are absolutely not of interest.

Of the in a liquid Medium coupled ultrasound causes, with appropriate dosage, however in particular also an effect of the uniform spreading of kinetic Energy to form a longitudinal pressure wave.

Of the Change of compression and expansion phases causes a change or overpressure in the medium. While at overpressure the molecules the liquid pushed together, they are pulled apart under negative pressure. exceeds the size of the negative pressure the tensile strength of the liquid, become cavities formed in the liquid, so-called cavitation bubbles.

In In heterogeneous systems, cavitation occurs preferentially at phase interfaces. The implosion of cavitation bubbles is asymmetric. The case resulting shockwaves and a fine high-accelerated liquid jet can Dissolve particles of solids.

this Effect makes you for example, by using stationary cleaning baths with a capacity of up to 90 l the effect of a coupled-in ultrasound be exposed in the frequency range of 20 to 100 kHz. The celebration with the container connected piezoelectric vibrators conduct the mechanical vibrations into the bath, whereby the objects inserted in it from adhering Particles, fats u. a. be freed. One speaks in this device from an indirect sonication reactor. The sound comes as such this undirected to unfold.

A further technical training is the ultrasonic horn consists of an RF converter, a horn and a sonotrode. This System belongs to the direct publicity reactors, where with a frequency is worked from 20 to 60 kHz. The application of such reactors is z. B. given for homogenization, emulsification and digestion of cells of colloidal substances. The sonotrode tips conduct the vibrational energy focused in the appropriate medium.

So-called Immersion oscillators are plate-shaped or disc-shaped, with their Application takes place in direct or indirect reactors. they work in frequency ranges from 20 kHz to 22 MHz, with a power of up to 8 KW.

In In chemistry, flow reactors are used to influence a volume flow used in terms of its pressure and temperature. Of the Coupled ultrasound is scattered or focused here brought to action.

In In practice, for example, the flow reactor after the Martin-Walter push-pull system enforced.

at This system is a vibration tube, which above and is provided below with an ultrasonic transmitter. Due to the dimension and the geometry is only half the wavelength generated. The system belongs to the most powerful Ultrasound systems and can be used in a tube (stationary) as a flow reactor to be built in.

The representatively taken from the prior art solutions in its present training, however, not applicable, if it it comes, drinking and / or sewers, in particular existing from metallic or ceramic materials, to regenerate in their flow capacity.

It It is therefore an object of the invention to propose a method with continuously advancing to a definable length of one to be treated pipe section incrustations, biofilms, etc. are solved without damaging the pipe inner walls, wherein controllable change of a einkoppelbaren ultrasound in definable limits with respect to his Frequency and transmittable power particular mechanical impact on the locally different firm adherent layers for their solution is taken and at the same time over the propulsion of an ultrasonic probe in the existing coupling medium the solved ones Particles are removed from the immediate site of action in this Senses a post-purification, which is - outside the process of the invention - a known pipe rinse followed.

According to the invention, the object is as follows is solved, reference being made to the basic inventive idea of claim 1. The further embodiment of the invention results from the claims 2 to 5.

The following supplementary Information on the teaching according to the invention are required.

The made of metallic or non-metallic materials Pipe systems of a drinking and / or sewage network are located in the Use by slowly depositing incrustations unwanted biological deposits on the tube inner wall. That leads to Minimization of optimally recoverable Volume flow, which is not unlimited by pressure increases z. B. can be compensated in a drinking water network.

It It was found that a self-propelled in a coupling medium locomotive Probe, which sends non-directional ultrasound, loose to firmly adhering Incrustations and / or biofilms that dissolve dirt particles locally, though the coupled ultrasound has a frequency of up to 50 kHz. there can be a performance of the registered, in particular mechanical energy, of up to 2 KW can be achieved. An ultrasonic (HF) generator generated for this the ultrasonic energy generated by a downstream amplifier a higher one Level to transfer is transformed into the ultrasound probe. The latter sends the Ultrasound from at least 2 sound emitting end sections their front area in the surrounding liquid amount of naturally in the corresponding pipeline already existing coupling medium.

The while the cleaning with ultrasound shut off from the rest of the pipe network Pipe is in a defined length, which in the first place of the individually locally given possibilities depends on a shouting, continuously from the self-acting, centered in the pipeline Floating moving Ultrachallsonde drive by these next Supply lines for transmission the ultrasound energy a feeder for under has defined pumping pressure standing drinking or service water, which are arranged behind the ultrasound probe and arranged obliquely upwards, applied downward and laterally directed jet nozzles. Your in one certain angles emitted pressure jets always cause central alignment of the ultrasonic probe in the tube interior, their continuous propulsion and finally a local post-purification by means of the emitted Ultrasonic on or already detached incrustations and / or colloidal substances.

The Cleaning effect can to a certain extent the frequency increase to Generation of the ultrasonic energy can be made variable. Further Influencing factors are the ambient temperature of the coupling medium in the pipeline to be cleaned and the existing fluid pressure in the coupling medium.

The inventive method makes use of the induced in the coupling medium by means of ultrasound physical (in incrustations) and concomitant chemical changes (eg colloidal substances) to act on these undesirable conditions in the tube interior solving or agglomerating. This process can be explained as follows:
Cavitation occurs on the solid surface, ie. cavities are formed in the liquid, which, depending on their gas content, either strongly pulsate in the rhythm of the sound vibrations, or which arise and collapse in an irregular sequence (implusion). As a result, the solid dirt particles are loosened, also caused strong local currents through which the dirt particles are torn off and the dissolution of soluble impurities is greatly accelerated. The cavitation intensity is strongly frequency dependent, the highest efficiency is achieved at 20-50 KHz.

One Another crucial process is the resuscitation and solution of the colloidal substances that have settled in the pipeline and the comminution of macromolecules.

• – plastische Verformung weicher Feststoffe/Metalle, Aufbrechen harter Oxidschichten auf weichen Metallen
• – Ablösen der Oxidschichten auf harten Metallen
• – Erosion und Aufbrechen der Oberflächenstruktur (Oberflächenvergrößerung, tieferes Eindringen von Reaktanten), Permeabilisation von Membranen
• – Entfernen von Oberflächenverunreinigungen, Ablösen einer Produktschicht
• – Verringerung der Induktionsperiode

As a result, the following effects can be achieved as summarized below: Effects on solid surfaces

• Plastic deformation of soft solids / metals, breaking up of hard oxide layers on soft metals
• - Removal of the oxide layers on hard metals
• - erosion and rupture of the surface structure (surface enlargement, deeper penetration of reactants), permeabilization of membranes
• - Removal of surface contaminants, detachment of a product layer
• - Reduction of the induction period

Transport from and to solid surfaces

• - improved Mass and heat transfer
• - faster Removal of products, continuous transport of starting materials

Effects on particle accumulation

• - Particle size> Bubble size: reduction the particle size and dispersion the crushed particles
• - Particle size <bubble size: acceleration small particles and merging in the collision

Effects on liquid / liquid interfaces

• - Intense Homogenizing and emulsification (micromxing)
• - improved Mass and heat transfer between the phases

Reaction center: surrounding Liquid:

a. radical reactions

• Trigger of radical chains
• Reaction of dissolved Reactants with molecules formed in the bladder interior

b. Mechanical effects

• Intensive mixing of reactants (micromixing) education of emulsions of immiscible liquids Erosion and Cleaning of solid surfaces Remove of deposited product layers Surface enlargement, reduction of particle size mechanical Degradation of macromolecules reduction of diffusion layer accelerated heat and particle transport Disruption of the Solvation layer of dissolved molecules

The Invention will now be explained in more detail with reference to an embodiment.

there shows:

1 : The functional principle of the method in the chaining of the required functional elements

2 : The principal scheme of action in a possible application

The used reference symbols mean:

1

function generator

2

amplifier

3

ultrasound probe

4

Ultrasonic

5

coupling medium

6

pipeline

7

Encrustation / colloidal material

8th

supply line

9

Ringditsen

A function generator advantageously generates a frequency 20 up to 60 KHz, with a power of 2 000 W, after amplification in the amplifier 2 in the coupling medium 5 , in this case water, is coupled. This is done via the sound emitting end portions of the ultrasonic probe 3 in the front area, so that the ultrasound 4 , forming cavitations, within the coupling medium 5 spreads evenly on all sides. A boundary forms the tube inner wall, so that after continuous enlargement of a cavitation bubble and increasing its internal pressure conditions results in a shock-like discharge, with the result that a pressure surge associated with highly accelerated liquid jets, is formed. At the pipe inner wall of the pipeline 6 adhesive encrustation / colloidal substances 7 are thereby solved or molecularly changed so that the at the ultrasonic probe 3 arranged in their rear area annular nozzles 9 which radiate backward at an oblique angle to the rear, the dissolved particles whirl up and in the opposite direction with respect to the continu- ous forward movement of the ultrasonic probe 3 transport. In this sense, can also be spoken of a local post-cleaning. About the supply line 8th becomes the ultrasound probe 3 supplied with the necessary ultrasound energy and it receives for the ring nozzles 9 a supply of standing under pumping pressure drinking or service water, the latter possibly in the cleaning of sewers.

The ring nozzles 9 However, compressed air can also be applied.

The cleaning of a deported pipeline 6 is further improved under the above conditions by the coupling medium present in it 5 is exposed to a pressure of up to 16 bar.

After passing through the ultrasound probe 3 becomes the treated pipeline 6 rinsed and passivated, ie usually subjected to a final phosphating. The latter applies in particular to the field of drinking water systems when it comes to steel or cast steel pipes.

• – keine chemische Reinigung und daher keine komplizierte Nachreinigung notwendig sowie damit keine aufwändige Entsorgung der gelösten Reststoffe,
• – Es wird keine grobe mechanische Reinigung mit ggf. Beschädigung der Rohrinnenwandung, wie z. B. beim „Molchen" durchgeführt,
• – geringer technischer Aufwand zur Durchfuhrung des Verfahrens,
• – eine aufwändige Wiederinstandsetzung bis hin zur Neuverlegung ganzer Rohrsysteme im Trink- und Abwasserbereich kann vermieden werden – bis zur technisch erforderlichen Neuinstallation – geschuldet dem natürliche Verschleiß.

The advantages of the method are summarized in:

• - no dry cleaning and therefore no complicated subsequent cleaning necessary and thus no time-consuming disposal of the dissolved residues,
• - There is no rough mechanical cleaning with possibly damage to the pipe inner wall, such. B. carried out at the "pig",
• - little technical effort to carry out the process,
• - a time-consuming reconditioning up to the relocation of entire pipe systems in the drinking and wastewater sector can be avoided - up to the technically necessary new installation - owing to the natural wear.

Claims (5)

Method for cleaning pipes, in particular in drinking and waste water networks, by means of ultrasound, characterized in that an ultrasound probe ( 3 ) via their sound emitting end sections an ultrasound ( 4 ) in a surrounding coupling medium ( 5 ) einschallt and by means of circular present at its rear area water-emitting annular nozzles ( 9 ) floating in the middle of a pipeline ( 6 ) is moved forward in a defined speed and direction. Method for cleaning pipes, according to claim 1, characterized in that the frequency for generating the ultrasound in a range of 20 to 60 KHz. Method for cleaning pipes, according to claim 1, characterized in that the entry of the ultrasonic energy assumes a value of up to 2,000 W. Method for cleaning pipes, according to claim 1, characterized in that a pressure increase of the coupling medium ( 5 ) up to 16 bar. Method for cleaning pipes, in particular in drinking and waste water networks, by means of ultrasound using compressed air for the annular nozzles ( 9 ).