EP0634229A1 - Method, assembly and apparatus for internal cleaning and coating of pipelines - Google Patents

Abstract

The method for cleaning pipes, in particular installed pipelines (49, 31) envisages that an abrasive medium is passed through a pipe to be cleaned with at least one liquid and one gaseous fluid. The gaseous fluid is in this case present in excess. The acceleration of the mixture can take place by high and/or low pressure. As a result of the use of a liquid, a more protective cleaning can be achieved in contrast to known dry methods. The cleaned pipe is blown dry and subsequently coated with a plastic. The coating takes place by sucking in a synthetic resin plug. <IMAGE>

Description

The present invention relates to a method, a cleaning composition and a device for cleaning the inside of pipes, in particular installed pipelines, by means of a fluid and a blasting or abrasive agent.

Methods are known with which installed pipelines are cleaned with a compressed air / abrasive mixture. In a method of the second type, which e.g. in DE-A-3 235 506, an abrasive is mixed with a high-speed air jet and sent through the line to be cleaned. For thorough cleaning, an abrasive of great hardness, e.g. Sand. At the high flow velocities of approximately 80 m / s, however, the force of the sand grains often leads to bends at the deflection point. This effect is probably exacerbated by electrostatic charges in the dry sand / air mixture. The damaged pipe sections must be replaced, which reduces the economics of the process.

A disadvantage of the method described above is that the blasting agent emerges at the end of the lines at high speed. In order to prevent the large amount of dust associated with this, the blasting agent must be collected in a separate dedusting system, also because the health-damaging effects of dust, in particular quartz dust, are known. Another disadvantage of the method according to DE-A-3 235 506 is that the cleaning effect generally gets worse the longer the pipeline is. This is due to the fact that the grains of sand hit the pipe walls less and less frequently after a certain distance, and that the momentum directed at the pipe walls is also likely to decrease. A characteristic of the known sandblasting cleaning process is also that when cleaning a branched pipeline system, the abrasive is always added at the smaller pipe diameter and must be excreted with the larger pipe diameter, since in the opposite case there would be a risk of clogging. This procedure inevitably results in the main pipes of larger diameter being cleaned several times and excessively, with undesirable material removal being possible on pipe bends.

The invention aims to propose a cleaning method and a cleaning composition by means of which the disadvantages mentioned at the outset can be largely avoided. The method should be simpler to use than the known methods. In addition, a device for performing the method should be simple and inexpensive to purchase.

This is achieved according to the invention in that the abrasive is sent through at least one liquid and one gaseous fluid through a pipe to be cleaned. The particular advantage of the method according to the invention over the prior art is that the abrasive effect can be weakened by the addition of a liquid fluid. In practice, this is shown by the fact that pipe bends can largely be prevented from striking through. The advantageous effect of the liquid additive can be explained by the fact that the liquid acts as a "braking agent" for the abrasive grains and therefore enables the pipes to be cleaned more gently. On the other hand, the cleaning effect can be enhanced by a larger proportion of abrasive grains with a larger diameter. It is also advantageous that the tubes in any direction, as well as sector or. can be cleaned in sections. This means that "defined" pipe sections with a similar diameter can be cleaned and thus a uniform cleaning effect is achieved. This largely eliminates the risk of undesired material removal or pipe penetration. Another advantage of the method according to the invention is that, in contrast to the known prior art, no dedusting system is required, since no dust is generated. The procedure can be used Cleaning of pipes of any kind are used, especially of installed pipes for liquids or gases, whose cleaning with other methods is difficult because of the poor accessibility. With a suitable choice of liquid and gas, the process can also be used for pipes in which flammable media are transported. Due to the gentle cleaning, the process is particularly suitable for pipes made of softer or sensitive materials, such as copper or plastic pipes. Finally, the method has the advantage over the known drying methods that the pipes to be cleaned no longer have to be dried beforehand.

It is advantageous to swirl the abrasive and the liquid fluid by means of the gaseous fluid and to convey them through the pipe at a speed> approximately 1 m / s. The speed of the gaseous fluid can be somewhat higher than that of the abrasive / liquid mixture.

The abrasive, the liquid and the gaseous fluid are advantageously applied under approximately the same pressure, which is between 2 and 12 bar, preferably between 4 and 8 bar. As a result, the abrasive can be accelerated to a speed at which it causes the desired abrasive effect. The effect depends essentially on the type and possibly the composition of the abrasive, the amount of liquid and the speed of the abrasive. To generate an overpressure e.g. an air compressor can be used. The required high pressure water can e.g. can be branched off directly from a high pressure water connection. The abrasive, the liquid and the gaseous fluid can also be conveyed through the pipe by applying an overpressure and / or a vacuum.

The pressure is expediently applied intermittently. This can increase the abrasive effect of the abrasive. The pressure is advantageously set so that the Mixture of abrasive, the liquid and the gaseous fluid pulsates in the tube. This also results in an improvement in the grinding effect. It is advisable to reverse the running direction of the mixture at least once during the cleaning process. As a result, the pipe can also be cleaned at points which are at a blind angle in a certain direction of travel. In contrast to this, the running direction cannot be reversed in the drying process mentioned in the introduction, because when cleaning in the direction from the larger to the smaller diameter, the lines become blocked.

The abrasive and / or the liquid used is advantageously circulated and used several times. As a result, the disposal costs for a contaminated abrasive / liquid mixture are kept low.

It is advisable to blow dry the cleaned pipe after cleaning and then coat it with a plastic. The coating is advantageously carried out by sucking in a resin plug using a negative pressure. As a result, the other connection points only need to be closed without, as is the case when coating by means of an overpressure, an overpressure would also have to be set in the rest of the line system. If this was not done with the latter method, the resin plug would spread uncontrollably in the pipe system. It is advantageous to provide the cleaned tube with a second plastic layer after the first layer has at least partially polymerized. This enables particularly durable coatings to be produced. In addition, there is less of a risk that certain areas will not be coated. If the applied layers are also colored differently, the inner surfaces of the pipes can be checked relatively easily at a later point in time.

An apparatus for performing the method has a container for holding an abrasive, a Dosing device or a mixing tube having a metering valve, which connects the container to a pipe to be cleaned, and at least one feed line and / or connection point on the container and / or on the mixing tube for feeding at least one gaseous and one liquid fluid, and means for generating a transfer - And / or a negative pressure in order to swirl and accelerate the abrasive with the liquid and the gaseous fluid. This device is inexpensive and requires only a small amount of space.

A separator is expediently provided, which, via a first line having a pump, communicates with the feed lines or. Connection points for the liquid fluid, and is connected to the pressure vessel via a second line provided with a valve. This has the advantage that the liquid fluid and the abrasive used can be used several times.

A cleaning composition according to the invention for cleaning the inside of pipes, in particular installed pipelines, comprises 1 part by volume of abrasive, 1 to 12 parts by volume, preferably 3 to 7 parts by volume of a liquid and 80 to 3000 parts by volume, preferably 600 to 1'200 parts by volume of a gaseous fluid (at normal pressure), wherein the mixture of abrasive, liquid and gaseous fluid is sent through a pipe to be cleaned by applying an overpressure and / or a vacuum. This composition is particularly effective and allows gentle cleaning of pipes. Cleaning with this wet or damp mixture means that neither predrying nor vacuuming at the end of the pipe is necessary. The mixture filling the pipe ensures uniform all-round cleaning without the risk of pipe bends breaking through. Damage caused by static electricity is also avoided.

The liquid fluid water and the gaseous fluid air are advantageous. It is also advantageous if the abrasive is a mixture of different grain sizes. It has namely shown that the larger the grain diameter, the better the cleaning effect. A mixture of different grain sizes has the advantage that a good cleaning effect can be achieved with little risk of clogging. In this context, it should not be left unmentioned that the use of grain sizes of, for example, 6 mm would be unthinkable in the conventional dry cleaning methods mentioned at the beginning, since such grain sizes would inevitably lead to damage to the pipes.

It is advisable to add an inhibitor and / or cleaning additives to the mixture. A binder can also be added to create a paste that can be pressed through the lines.

Fig.1

eine vereinfachte, schematische Darstellung der erfindungsgemässen Vorrichtung,

Fig.2

eine typische Installation zur Reinigung eines Rohrsystems, z.B. eines Mehrfamilienhauses, mit einer Vorrichtung mit Fluid- und Abrasivmittelrückführung.

Exemplary embodiments of the invention are described below with reference to the figures. It shows:

Fig. 1

a simplified, schematic representation of the device according to the invention,

Fig. 2

a typical installation for cleaning a pipe system, e.g. an apartment building, with a device with fluid and abrasive return.

According to FIG. 1, a device 11 for carrying out the method according to the invention has a pressure container 13 for receiving an abrasive 15, lines 17, 19, 20 for supplying a liquid and a gaseous fluid into the pressure container 13 and into a mixing tube 21 which holds the pressure container 13 and a pipe 23 to be cleaned connects, as well as pressure medium, for example an air compressor 25, for generating an overpressure. The cleaning effect in the tube 23 with deposits is achieved by swirling an abrasive 15 and a liquid fluid with the gaseous fluid, accelerating it and sending it through the tube 23. It goes without saying that the gaseous and the liquid fluid are at approximately the same pressure to prevent the two fluids used from displacing each other.

In the exemplary embodiment according to FIG. 1, the gaseous fluid is supplied through line 17 and the liquid fluid through lines 19, 20. The liquid fluid, e.g. Water from a high-pressure water connection is already under pressure and can be shut off by valve 27. A pressure reducer 29 allows a certain pressure to be set. A part of the liquid fluid, usually water, is fed into the mixing tube 21 through the line 19, the rest is fed through the line 20 into the lower part of the container 13. The water fed into the container 13 has the purpose of wetting the abrasive so that it can be rinsed out of the container 13. A further high-pressure pump (not shown) can be provided in line 20.

The line 17, through which a compressed gas, usually air, is supplied, is connected to the mixing tube 21 at the outlet of the container 13. The line 17 has a shut-off valve 16 and a pressure regulator 18. The abrasive 15 can be passed into the mixing tube 21 through an adjustable valve 31 or a flap. If the valve 31 is opened, the pressure in the pressure vessel 13 is virtually the same as in the mixing tube 21.

By supplying a liquid fluid under excess pressure to the pressure vessel 13, the abrasive 15 and the liquid reach the mixing tube 21 with the valve 31 open, where they are swirled and accelerated by the gaseous fluid. Further liquid can be added to this mixture via line 19. This creates a mixture of these components, which, when accelerated to a certain speed, can effectively remove deposits in a pipe. Compared to the prior art, the use of this moist or wet mixture has the advantage that cleaning can be done more gently, no Pre-drying of the pipes is required and no dedusting system is necessary. The mixture emerging from the pipe with the removed impurities can be fed directly into the sewer, collected in a separate container or used again. A further significant advantage has turned out to be that the removed dirt and rust usually float on top of the water and can therefore be easily separated with the water. The abrasive can consequently be used several times without the effect of the same being appreciably impaired. The water used can also be recycled if the solid components are separated.

2 shows a typical installation for cleaning a pipeline system 31 of a multi-family house that extends over several floors. The device of Figure 2 differs from that of Figure 1 essentially only in that means are provided to use the abrasive and the water used several times. To simplify the illustration, the same reference numbers are used in FIG. 2 as in FIG. 1, as far as possible and expedient.

In contrast to FIG. 1, in the exemplary embodiment of a cleaning device 11 'in FIG. 2, a separator 33, for example a cyclone separator, is provided, in which the cleaning composition emerging from the pipeline system 31 is passed with the impurities. The separator 33 is connected to the pressure vessel 13 via a valve 35 or a slide. The deposited abrasive can be drained back into the pressure vessel 13 through the valve 35. A line 37 also allows the excess water of the separator 33 to be led into a water tank 39. The water tank 39 mainly has a storage function, but can be used as a further separator. From the water tank 39, the water can be fed back into the lines 19, 20 via a line 41 and a pump 43. The water tank 39 has a drain valve 45 on the bottom, which can serve cleaning purposes or the supply of water.

The pipe system 31 to be cleaned has a multiplicity of water connection points 47, which are located on different floors. The pipes of different floors are connected to each other by a main line 49. The cleaning device 11 'is connected to the water connection points 47 by means of the feed lines 22 and return lines 51. The supply lines 22 serve to supply the cleaning composition, and the return lines 51 serve to return the cleaning composition to the container 33. It has proven to be expedient to connect the supply lines 22 and return lines 51 alternately to adjacent water connection points 47. This has the advantage that the pipeline system 31 can be cleaned in sections.

A distributor battery 53 is provided at the end of the mixing tube 21. A large number of flow lines 22, advantageously in blocks, can be connected to this distributor battery 53. A connection battery (not shown) can also be provided on the separator 33, to which the return lines 51 can be connected in blocks. Due to this design, the feed lines 22 and return lines 51 can each be quickly connected either to the separator 33 or to the distributor battery 53. This allows the direction of rotation of the cleaning composition to be reversed quickly by changing the connection flanges. The flow and return lines 22, 51 have shut-off valves 55 at their respective water connection ends.

To put it simply, the cleaning process can be used as follows: In the pressure vessel 13, an abrasive such as quartz sand is filled with water in a suitable ratio. The mixing tube 21, which is connected to the pressure vessel 13 and a compressed air line 17, is located under the boiler. The output side of the mixing tube 21 is connected to a pressure jet hose or flow line 22 and the line pipe 23 to be cleaned or inserted into the line pipe. The The abrasive-water mixture is pressurized in the boiler 13 (for example approximately 5 bar). Dosed, it is then pressed into the mixing tube 21 or. drained and pressurized (e.g. 4 bar). The mixture is carried away and hurled through the conduit. At the end of the line, it can exit directly in a separator container to recover the blasting media. Suction at the end of the line is not necessary.

With this method, the conveying direction can then be reversed one or more times to make blind spots, e.g. Pipe fittings can be reached in both directions, as the sand as a means of transport is avoided when the sand is transferred to smaller pipe cross-sections.

To renovate a pipeline system of an apartment building, the procedure is as follows: First, all the fittings are removed from the pipeline system 31 to be cleaned. Then, as shown in FIG. 2, the supply lines 22 and return lines 51 are alternately connected to the water connections 47. The water tank 39 is filled with water (e.g. 400 liters). The entire pipeline system 31 is then filled with water. As soon as this has happened, all valves 55 are closed. The pressure vessel 13 is filled with approximately 50 liters of an abrasive, e.g. of a granular corundum, filled. The corundum is advantageously a mixture of different grain sizes, in this example the maximum grain size is approximately 3 to 4 mm (diameter of the piping system: between 3/8 '' and 5/4 ''). For larger pipe diameters, at least some of the grains can have a correspondingly larger grain diameter.

For cleaning, two adjacent shut-off valves 55 are now opened and the pipe section lying between the two water connections is first expediently rinsed with water (approx. 50 l / min, 5-6 bar). The next step is to convey the abrasive with compressed air and water through the pipe section to be cleaned. 8 - 10 Nm³ per minute (Normal cubic meter) air is blown into the mixing tube 21 at a pressure of approximately 6 to 8 bar. About 3 liters of water per minute (5.5 to 8 bar) are added to the abrasive in the pressure vessel 13 via the line 20. After valve 31, high pressure water (30 to 80 l / min; 5.5 to 8 bar) is added to the abrasive / water / air mixture. The abrasive / water mixture is advantageously accelerated to a speed of approximately 1 to 10 m / s by the compressed air. The air used flows through the pipe at a speed between approximately 30 and 100 m / s. In a specific case (pipe 3/8 '' to 5/4 '') speeds of approx. 3 m / s for the abrasive and the liquid, and approx. 60 m / s for the air were calculated.

A particularly efficient cleaning effect can be achieved if a pulsating or vibrating flow occurs in the feed lines 22. This "pulsation" can be achieved by varying the air pressure and / or water pressure. This pulsation can optionally also be increased by the pump 43. The pump 43 can e.g. be a compressed air powered water high pressure pump. Cleaning the pipe section with the abrasive takes about 5 minutes. The feed and return lines 22 and 51 are then exchanged, i.e. the supply lines 22 are connected to the separator 33 and the return lines 51 to the valve battery 53, so that the direction of the cleaning composition is just reversed. The process described above is repeated for all pipe sections until the entire pipe system 31 is cleaned.

In the case of lines with a larger diameter, the supply line or delivery hose can be equipped with a special nozzle head and inserted into the lines. The nozzle outlet openings are advantageously directed towards the rear (with respect to the direction of conveyance), which promotes all-round ejection of the mixture under pressure against the tube walls and at the same time the forward movement of the hose. The mixing ratio of water / abrasive can range from "wet blasting" to the pipe diameter and the degree of incrustation "Wet jets" can be adjusted in such a way that an optimal and gentle interior cleaning is achieved.

After the cleaning process, the system is rinsed thoroughly with fresh water. A passivating agent can be added to the rinsing water, which is intended to prevent the build-up of rust film on the bright metallic inner surfaces of the pipe during the drying process. A suitable alkaline passivating agent is e.g. the product 31.00 from the company CM, CH-5612 Villmergen. The rinse water can also be heated to accelerate the subsequent drying process.

After rinsing / passivation, the piping system is preferably dried with preheated air and the pipes are warmed to a temperature of 20 to 40 ° C. The heated air can be distributed to all water connections at the same time by an air distributor and the air can be discharged through line 49. The drying process takes about 30 to 60 minutes.

For the subsequent internal coating, the required amount of a synthetic resin, preferably an epoxy resin, is allocated to each pipe section (approx. 80 g per running meter of a 1/2 '' pipe). The synthetic resin is blown into the pipes by means of compressed air using a suitable device or simply through a piece of hose filled with epoxy resin, which is installed immediately before the water connection. The pressure and air volume must be adapted to the pipe diameter and the viscosity of the resin (e.g. overpressure coating: 2.5 bar, 5 to 8 Nm³, pipe diameter: 3/8 '' to 5/4 '').

During the coating, a back pressure is built up on all other connections with air, which is preferably regulated or regulated with pressure gauges. is set. The pressure can be set beforehand without resin.

A second method of coating is to apply a quantity of synthetic resin to the entire piping system Blow in the most distant water connection and use the compressed air to blow to the nearest, closer water connection. The arrival of the synthetic resin at the next water connection can be observed, for example, through a transparent hose attached to the water connection. As soon as the synthetic resin appears, it is blown back and transported to the next water connection.

A third and very simple coating method is to suck up the coating material using a vacuum pump. The negative pressure is applied to the main line. sucked and with each water connection the appropriate amount of resin entered by opening a valve. The advantage of this method is that no plugs can form on blind lines, etc. and that there are no blockages. This method can be used with particular advantage for ring pipes with many water connections and outlets.

Depending on requirements, a second, possibly differently colored resin layer can be applied after the first coating in the manner described above.

After the coating process (duration approx. 20 to 40 minutes), warm air (with reduced pressure) is blown through until the polymerization process has started.

After approx. 24 hours, water can be added to the renovated piping system.

Claims (18)

Method for cleaning the inside of pipes, in particular installed pipelines, by means of a fluid and a blasting or abrasive agent, characterized in that the abrasive agent is sent through at least one liquid and one gaseous fluid through a pipe to be cleaned. A method according to claim 1, characterized in that the abrasive and the liquid fluid are swirled by the gaseous fluid and are conveyed through the tube at a speed> approximately 1m / s. A method according to claim 1 or 2, characterized in that the abrasive, the liquid and the gaseous fluid are applied under approximately the same pressure, which is between 2 and 12 bar, preferably between 4 and 8 bar. Method according to one of claims 1 to 3, characterized in that the pressure is applied intermittently. Method according to one of claims 1 to 4, characterized in that the pressure is adjusted so that the mixture of abrasive, the liquid and the gaseous fluid pulsates in the tube. Method according to one of claims 1 to 5, characterized in that the running direction of the mixture is reversed at least once during the cleaning process. Method according to one of claims 1 to 6, characterized in that the abrasive, the liquid and the gaseous fluid is conveyed through the pipe by applying an overpressure and / or a vacuum Method according to one of claims 1 to 7, characterized in that the abrasive used and or the liquid is circulated and used several times. Method according to one of claims 1 to 8, characterized in that the cleaned tube is blown dry and then coated with a plastic. Method according to one of claims 1 to 9, characterized in that the coating is done by sucking in a resin plug by means of a negative pressure. Method according to one of claims 1 to 10, characterized in that the cleaned tube is provided with a second plastic layer after the first layer is at least partially polymerized. Device for cleaning the inside of pipes, in particular of installed pipes (31), by means of an abrasive and a fluid, characterized by a container (13) for receiving an abrasive (15), a mixing pipe (21) having a metering device or a metering valve (31) ), which connects the container (13) with a pipe (23) to be cleaned, and at least one feed line (17, 19, 20) and / or connection point on the container (13) and / or on the mixing pipe (21) for feeding at least in each case a gaseous and a liquid fluid, and means (25) for generating a positive and / or negative pressure in order to swirl and accelerate the abrasive with the liquid and the gaseous fluid. Apparatus according to claim 12, characterized in that a separator (33) is provided, which via a first, a pump (43) having line (41) with lines 19 and / or 20, respectively. Connection points for the liquid fluid, is connected and is connected to the container (13) via a second line provided with a valve (35). Composition for cleaning the inside of pipes, especially of installed pipelines - 1 part by volume of abrasive, - 1 to 12 parts by volume, preferably 3 to 7 parts by volume of a liquid and 80 to 3000 parts by volume, preferably 600 to 1200 parts by volume of a gaseous fluid (at normal pressure), wherein the mixture of abrasive, liquid and gaseous fluid is sent through a pipe to be cleaned by applying an overpressure and / or a vacuum. Composition according to claim 14, characterized in that the liquid fluid is water and the gaseous fluid is air. Composition according to claim 14 or 15, characterized in that the abrasive is a mixture of different grain sizes. Composition according to one of claims 14 to 16, characterized in that the mixture can have grain sizes of up to about 10 mm, preferably up to about 6 mm. Composition according to one of Claims 14 to 17, characterized in that a binder is added to the mixture.

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