METHOD FOR CLEANING WALL SECTIONS OF LIQUID-BEARING AREAS OF A PLANT AND A PLANT

Description

[0001] The present invention relates to a method for cleaning wall sections of liquid-carrying areas of a system. Furthermore, a system with liquid-carrying areas, which include wall sections to be cleaned, is described. The liquid-carrying areas are, for example, pipelines and / or fittings of the system. A method for cleaning objects is also described.

[0002] Cleaning sections of walls in hard-to-reach, liquid-carrying areas has always been challenging. The use of aggressive cleaning agents, capable of removing even stubborn, difficult-to-dissolve dirt, is well-known. Another common practice is cleaning liquid-carrying areas using so-called pipe pigs. Pipe pigs are sponge-like or plug-like devices with circumferential cleaning seals. They are pushed through the liquid-carrying areas to scrub the wall sections requiring cleaning. The disadvantage of pipe pigs is that their cleaning is essentially limited to liquid-carrying areas with a constant cross-section. Cleaning fittings, for example, is only possible to a very limited extent using pipe pigs.

[0003] From EP 1 484 068 A1, a device for cleaning wall sections of a container and a method for operating this device according to the preamble of claim 1 are known, wherein the container is fed with a liquid and pressure fluctuations are caused in the liquid, which cause cavitation and thereby bring about cleaning.

[0004] Even with other common objects, there are often hard-to-reach areas that cannot be cleaned mechanically. In these cases, the use of aggressive cleaning agents is often either impossible or undesirable.

[0005] The present invention is based on the objective of providing a means for the quick and efficient cleaning of wall sections of liquid-carrying areas of a plant. Disclosure of the invention

[0006] The problem underlying the invention is solved by a method with the features of claim 1.

[0007] According to the invention, the method according to claim 1 provides that at least one fluid-carrying area to be cleaned, designed as a pipe or fitting, is filled with a cleaning fluid. A section of the wall of this area to be cleaned is then in contact with the filled cleaning fluid. A pressure modulation chamber is also provided. The area to be cleaned, filled with cleaning fluid, is in fluidic communication with the pressure modulation chamber. Following the filling with cleaning fluid, the pressure in the pressure modulation chamber is reduced. Specific implementations for reducing the pressure are explained in more detail below using possible examples. Due to the fluidic communication with the cleaning fluid, the pressure of the cleaning fluid also decreases as a result of the pressure reduction in the pressure modulation chamber. This leads to the formation of gas bubbles in the cleaning fluid.The gas bubbles clean the section of wall in contact with the cleaning fluid. The gas bubbles adhere to the dirt on the wall section and lift it away. Additionally, the gas bubbles can also form between the wall section and the dirt, repelling the dirt from the wall section.

[0008] The formation of gas bubbles can occur through evaporation of the cleaning fluid (due to a drop in pressure), also known as spontaneous boiling, and / or through the outgassing of a substance dissolved in the cleaning fluid. For example, readily soluble gases such as CO2 or NH3 dissolved in water can be used as the cleaning fluid. An example of an organic cleaning fluid with a dissolved component that can outgas is, for example...

[0009] Propane dissolved in heptane (or in cleaning naphtha). Other volatile substances can also be used dissolved in an organic cleaning fluid.

[0010] The gases, or the substances that later outgas, are introduced under pressure, e.g. with an injector, directly into the cleaning fluid and dissolve in it.

[0011] The colder the cleaning fluid, the better the substances to be dissolved (the gases that later degas) dissolve. The substances are expelled by a sudden drop in pressure (bubbles, formation of bubbles) and escape from the liquid phase. This outgassing can be further enhanced by prior and / or simultaneous heating of the saturated or partially saturated cleaning fluid (= supersaturation). In this process, the pressure is reduced (possibly with a simultaneous increase in temperature) until the cleaning fluid is supersaturated and the dissolved substance is released as a gas.

[0012] After decompression (i.e., after degassing), the gases can, for example, be fed back into the possibly cooled cleaning fluid via an injector using a compressor and dissolved, or, similar to quenching, they can be dissolved again by spraying ice-cold cleaning fluid into the pressure modulation chamber and pumped back into the system.

[0013] Preferably, the pressure in the pressure modulation chamber is reduced abruptly. This allows for effective formation of gas bubbles, which is accompanied by a thorough cleaning of the wall section.

[0014] In particular, the method according to the invention has the advantage that even difficult-to-access areas, such as crevices in the wall section, can be effectively cleaned. The formation of gas bubbles even preferentially occurs in crevices and on dirty, rough surfaces.

[0015] The plant is preferably a process engineering, chemical, food processing, or pharmaceutical plant (a plant can be both a process engineering and a chemical plant). A process engineering plant within the meaning of this disclosure is any plant in which process engineering steps are carried out (this includes chemical reactions, physical process steps, e.g., physical separation processes, thermal separation processes, e.g., distillation, mixing processes, homogenization processes). In a chemical plant, chemical reactions are typically carried out in this sense. In a pharmaceutical plant, pharmaceutical active ingredients are processed. In a food processing plant, foodstuffs or their constituents or ingredients are processed, e.g., packaged, heat-treated, or similar processes.Thorough cleaning is particularly crucial in such systems to ensure that the substances being processed, such as chemical or pharmaceutical products, can be manufactured with a high degree of purity. In particular, at least some of the gas bubbles collapse or implode after their formation. This implosion or sudden collapse of the gas bubbles creates...

[0016] Cleaning fluid jets assist in cleaning the wall section. The formation and sudden collapse of the gas bubbles is also known as cavitation. This allows even stubborn dirt to be removed, as cavitation produces high-velocity fluid jets when the bubbles collapse.

[0017] According to the invention, the pressure modulation chamber is at least partially provided in a cleaning device that can be handled independently of the system. This has the advantage that, to carry out the method in a system, only minor design modifications to the system itself are necessary. The cleaning device can be combined with a variety of different systems in order to then carry out the method in these systems. To carry out the method, the pressure modulation chamber of the cleaning device is detachably or reversibly connected fluidically to the area to be cleaned. Preferably, the area to be cleaned is first filled with the cleaning fluid. Only then is the pressure modulation chamber connected fluidically to the area to be cleaned. Alternatively, preferably, the pressure modulation chamber is first connected fluidically to the area to be cleaned.Only then is the area to be cleaned filled with the cleaning fluid.

[0018] For example, it may be provided that the area to be cleaned is fluidically separated from the rest of the system, so that the pressure can be easily changed via the pressure modulation chamber.

[0019] Preferably, the pressure modulation chamber is at least partially filled with gas before the pressure is reduced. If the pressure modulation chamber is filled with gas before the pressure is reduced, the pressure or gas pressure in the pressure modulation chamber can be precisely set before the pressure is reduced. Furthermore, a particularly rapid pressure reduction in the pressure modulation chamber can be achieved.

[0020] Preferably, the pressure in the pressure modulation chamber exceeds the ambient pressure before the pressure is reduced. If the pressure in the pressure modulation chamber exceeds the ambient pressure, a significant pressure reduction can be achieved, i.e., a reduction from a high pressure level to a lower pressure level that differs considerably from the high pressure level; for example, a reduction of 10 bar can be easily achieved. This is accompanied by the effective formation of gas bubbles and a thorough cleaning of the wall section. Preferably, in this embodiment of the method, the pressure modulation chamber is first fluidically sealed off from the environment. Subsequently, the pressure in the pressure modulation chamber is increased to a value exceeding the ambient pressure. Only then is the pressure in the pressure modulation chamber reduced.

[0021] According to a preferred embodiment, the pressure in the pressure modulation chamber is reduced by releasing gas from the chamber. This allows for a particularly rapid pressure reduction, which is accompanied by the effective formation of gas bubbles. Preferably, the gas is released into the environment. This embodiment of the method is structurally simple to implement. Advantageously, the pressure in the pressure modulation chamber is increased before the release so that it exceeds the ambient pressure. For example, the gas is released from the pressure modulation chamber by opening at least one release valve located between the chamber and the environment. Alternatively, the gas is preferably released into a discharge chamber that is sealed off from the environment.This has the advantage that the process can also be used with substances that should not be released into the environment. In particular, a negative pressure is maintained in the discharge chamber before the gas is released. A negative pressure is a pressure lower than the ambient pressure. Preferably, the negative pressure in the discharge chamber is generated by a pump. Alternatively or additionally, the pressure in the pressure modulation chamber is increased before the gas is released into the discharge chamber.

[0022] Preferably, the cleaning fluid is heated after filling the area to be cleaned. Heating the cleaning fluid allows for a significant increase in pressure within the pressure modulation chamber. Advantageously, the pressure modulation chamber is temporarily sealed off from the surroundings. Preferably, the cleaning fluid is heated to a temperature higher than its boiling point at ambient pressure. The pressure modulation chamber is then filled with vaporous cleaning fluid. When the cleaning fluid is heated to such a high temperature, the formation of gas bubbles is particularly pronounced when the pressure in the pressure modulation chamber is reduced. In particular, the cleaning fluid spontaneously boils when the pressure is reduced, which can cause vigorous bubbling.Heating the cleaning fluid also has the advantage of increasing its own dirt-dissolving properties. This heating is typically achieved using a heat exchanger and / or steam injection.

[0023] Preferably, the gas present in the pressure modulation chamber before the pressure reduction is predominantly a cleaning fluid in vapor form. The pressure reduction in the pressure modulation chamber is particularly preferably achieved by condensing the cleaning fluid in the chamber. Condensation of the cleaning fluid allows for a sufficiently rapid, and especially instantaneous, pressure reduction in the chamber. Condensation of the cleaning fluid also offers the advantage that cleaning fluids intended to be kept out of the environment can be used. Preferably, the pressure modulation chamber is positioned above the area to be cleaned such that the cleaning fluid condensed in the chamber flows back into the area being cleaned. This condensed cleaning fluid is then also available for a subsequent cleaning cycle.

[0024] Preferably, the pressure in the pressure modulation chamber is reduced by cooling the pressure modulation chamber. A sufficient pressure reduction in the pressure modulation chamber can also be achieved by cooling the pressure modulation chamber. Preferably, the pressure modulation chamber is cooled such that the pressure reduction occurs at least partially through condensation of vaporous cleaning fluid within the pressure modulation chamber.

[0025] Preferably, the pressure modulation chamber is cooled by spraying cooled cleaning fluid into it. This causes the vaporous cleaning fluid present in the chamber to condense on the cooled fluid. This results in an abrupt pressure drop in the chamber, which in turn triggers the formation of gas bubbles. In particular, the cleaning fluid is atomized during spraying. This achieves a rapid condensation of the vaporous cleaning fluid.

[0026] Preferably, the pressure modulation chamber is cooled by a heat exchanger. The cleaning fluid present in the pressure modulation chamber then condenses on the heat exchanger. This condensation on the heat exchanger also causes an abrupt pressure drop in the pressure modulation chamber, which in turn triggers the formation of gas bubbles.

[0027] According to a preferred embodiment, the pressure in the pressure modulation chamber is reduced by at least one pump. The pump can, for example, remove gas present in the pressure modulation chamber to lower the pressure. For instance, the pump can remove the gas from the pressure modulation chamber to the environment or to a drain chamber that is fluidically sealed from the environment. The pump can also achieve a sufficiently rapid reduction of the pressure in the pressure modulation chamber. Preferably, a vacuum pump is used.

[0028] Preferably, a gas-enriched liquid is used as the cleaning fluid. When using a gas-enriched liquid, the effect of gas bubble formation upon pressure reduction in the cleaning fluid is particularly pronounced. Consequently, a particularly effective cleaning of the wall section of the area to be cleaned can be achieved. The use of a gas-enriched liquid can be combined with all of the previously described methods for reducing the pressure in the pressure modulation chamber. In particular, heating the cleaning fluid is not necessary when using a gas-enriched liquid.

[0029] Preferably, a water-based cleaning fluid is used. This has the advantage that any leakage of the cleaning fluid into the environment is not a problem. Furthermore, using a water-based cleaning fluid offers the advantage that the cleaning fluid has a pronounced dirt-dissolving effect against inorganic as well as polar organic contaminants (e.g., organic encrustations such as proteins, polysaccharides, urea).

[0030] According to a preferred embodiment, the cleaning fluid is a liquid comprising at least one organic solvent (this can be used alternatively or in addition to the aforementioned water-based liquid). This has the advantage that the cleaning fluid exhibits a pronounced dirt-dissolving effect against organic soiling. Furthermore, organic solvents are typically characterized by their low surface tension, allowing the cleaning fluid to penetrate even small crevices in the wall section to be cleaned.

[0031] Preferably, the pressure in the pressure modulation chamber is increased again after being lowered. Increasing the pressure promotes the implosion or sudden collapse of the gas bubbles formed by the pressure drop. As mentioned previously, the implosion of the gas bubbles enhances the cleaning effect. For example, the pressure is increased by closing a drain valve and by venting (or adding liquid to) the pressure modulation chamber. Preferably, several cleaning cycles are carried out as part of the process, with the pressure in the pressure modulation chamber first being lowered and then raised again in each cycle. Performing several cleaning cycles results in a particularly thorough cleaning of the wall section to be cleaned.

[0032] As already mentioned, a system is also described. The fluid-carrying areas of the system can be filled with a cleaning fluid. The cleaning fluid is fluidically connected, or fluidically connectable, to a pressure modulation chamber in the fluid-carrying areas. The pressure modulation chamber is at least partially part of a cleaning device that is detachably connected to the system and can be operated independently of the system. For example, the pressure modulation chamber of the cleaning device is fluidically connected, or connectable, to the fluid-carrying area of ​​the system to be cleaned via a screw connection. Furthermore, means for changing the pressure in the pressure modulation chamber are provided. The method according to the invention can be carried out in the described system.The advantages and further training opportunities of the process are to be understood as being described in relation to the plant, and conversely, the advantages and further training opportunities of the plant are to be understood as being described in relation to the process.

[0033] Preferably, the means comprise at least a drain valve associated with the pressure modulation chamber, at least a metering device for spraying cooled cleaning fluid into the pressure modulation chamber, at least a heat exchanger for cooling the pressure modulation chamber and / or at least a pump.

[0034] As already mentioned, a procedure is also described.

[0035] The process is used for cleaning objects. It comprises the following steps: placing at least one object to be cleaned in a cleaning chamber of a cleaning unit, which is filled or will be filled with a cleaning fluid. The object can therefore be placed in the cleaning fluid or the cleaning fluid can be poured over the object.

[0036] The cleaning room is typically a pressure-tight sealed room within the cleaning unit.

[0037] The process includes the following step: lowering the pressure in the cleaning chamber containing the cleaning fluid and the item to be cleaned, causing gas bubbles to form in the cleaning fluid. The gas bubbles clean the item. During this process, some of the gas bubbles collapse after their formation. In particular, cavitation, i.e., the formation and sudden collapse of gas bubbles, can occur during the cleaning process.

[0038] The process for cleaning objects can be used, for example, to treat refurbished electronic devices (computers, monitors, mobile phones, etc.). Following the steps described so far, the process can include a drying step. For this, vacuum drying can be performed (e.g., at 1 bar > p > 0.06 bar). The drying process can be supplemented with heat input, e.g., via conduction or infrared radiation, to supply the energy of the enthalpy of vaporization. Non-sensitive parts (with or without robust electronics) can also be exposed to microwave heating. Drying can also be achieved by freeze-drying. For this, the triple point is undercut by a corresponding pressure reduction, e.g., below 0.06 bar. This results in a transition from the solid to the gaseous state of the liquid to be dried.

[0039] The cleaning room is in fluidic connection with a pressure modulation room.

[0040] The pressure modulation chamber may be partially filled with gas before the pressure is reduced. The pressure in the pressure modulation chamber may, in particular, exceed the ambient pressure before the pressure is reduced. Specifically, the pressure in the pressure modulation chamber can be reduced by releasing gas from the chamber. The gas may be released into the environment or into a vent chamber that is closed off from the environment. In particular, a negative pressure may exist in the vent chamber before the gas is released.

[0041] The cleaning fluid can be heated after filling the cleaning chamber, in particular by means of a heat exchanger and / or by steam injection.

[0042] Before the pressure is reduced, the gas in the pressure modulation chamber may consist predominantly of cleaning fluid in vapor form. In particular, the pressure reduction in the pressure modulation chamber can be achieved by the condensation of the cleaning fluid in vapor form, especially by a sudden condensation. The pressure in the pressure modulation chamber can also be reduced, in particular, by cooling the chamber. Cooling can, for example, be used to initiate the condensation of the cleaning fluid in vapor form.

[0043] The pressure modulation chamber can be cooled by spraying cooled cleaning fluid into it. The cleaning fluid can be atomized during spraying. Alternatively or additionally, the pressure modulation chamber can be cooled by a heat exchanger.

[0044] The pressure in the pressure modulation chamber can also be reduced alternatively or additionally by a pump.

[0045] In the process according to the invention, a gas-enriched liquid can be used as the cleaning fluid. Alternatively or additionally, a liquid comprising water can be used as the cleaning fluid. Alternatively or additionally, a liquid comprising at least one organic solvent (e.g., heptane, octane, white spirit, or similar organic solvents that are liquid at ambient conditions) can be used as the cleaning fluid. Inorganic solvents can also be used as the cleaning fluid or be a component of the cleaning fluid. Examples of such inorganic solvents, besides water, are liquid solutions comprising ammonia (NH3), sulfur dioxide (SO2), liquid hydrogen fluoride (HF), thionyl chloride (SOCl2) and / or sulfonyl chloride (SO2Cl2), hydrochloric acid (HCl), and / or sulfuric acid (H2SO4).Ammonia (NH3), sulfur dioxide (SO2), liquid hydrogen fluoride (HF), thionyl chloride (SOCl2) and / or sulfonyl chloride (SO2Cl2), hydrochloric acid (HCl) and / or sulfuric acid (H2SO4) can alternatively be used as pure substances, which liquefy at sufficiently high pressure and / or low temperatures. These substances, as pure substances and / or their solutions, have solvent properties that differ from water and can be utilized accordingly.

[0046] The invention is described in more detail below with reference to the figures, whereby identical or functionally equivalent elements are optionally identified only once by reference numerals. The description serves as an example and is not to be understood as limiting.

[0047] They show: Figure 1 a system with a cleaning device, Figure 2 a system with a cleaning device, Figure 3 a system with a cleaning device, Figure 4 a system with a cleaning device, Figure 5 a system with a cleaning device, Figure 6 a cleaning of a wall section of the system using gas bubbles, Figure 7 a system with a cleaning device and an injection device and Figure 8 a cleaning unit with cleaning room.

[0048] Figure 1 Figure 1 shows a schematic representation of Plant 1. Plant 1 is a general process engineering liquid-carrying plant; for example, Plant 1 is a chemical plant, a food processing plant, or a pharmaceutical plant. Plant 1 has several liquid-carrying areas, of which in Figure 1Only a section of pipe 2 is shown. Pipe 2 has a pipe wall 3 which encloses an interior space 4 of pipe 2.

[0049] The system 1 includes a heating device 6, which is only indicated. The heating device 6 is designed to heat a liquid in the pipeline 2. For example, the heating device 6 is designed as a steam injection device 7. Alternatively, the heating device 6 is designed, for example, as a heat exchanger.

[0050] A cleaning device 8 is assigned to the system 1. The cleaning device 8 is independently manageable and removable or detachably connected to the system 1. The cleaning device 8 has a container 9 with a pressure modulation chamber 10. The pressure modulation chamber 10 is fluidically connected to the interior 4 of the pipeline 2. In this case, the system 1 has a first fluid line 11 that is fluidically connected to the interior 4. The cleaning device 8 has a second fluid line 12 that is fluidically connected to the pressure modulation chamber 10. The first fluid line 11 is fluidically connected to the second fluid line 12 by a detachable fluid connection 13. The fluid connection 13 is, for example, designed as a screw connection 13.

[0051] The cleaning device 8 includes means 14 for changing the pressure in the pressure modulation chamber 10. In the case of the Figure 1In the illustrated embodiment, the means 14 comprise a drain valve 15 associated with the pressure modulation chamber 10. The drain valve 15 acts between the pressure modulation chamber 10 and the environment.

[0052] The following will be discussed with additional reference to Figure 6 An advantageous method for cleaning the system 1 using the cleaning device 8 is explained in more detail. Figure 6 Figure 1 shows an enlarged view of a pipe wall section 5 of the pipe wall 3 during the cleaning of the system 1 at successive time points. As can be seen from Figure 6 As can be seen, pipe wall section 5 of pipe wall 3 has a crack 16. Furthermore, pipe wall section 5 of pipe wall 3 exhibits contamination 17, at least at the beginning of the process.

[0053] It is assumed that the cleaning device 8 is disconnected from the system 1 at the beginning of the process. However, this is not essential according to the invention. First, the pipeline 2 is filled with a cleaning fluid 18. This filling can also be carried out with the cleaning device 8 already connected. The cleaning device 8 can also be part of the system 1.

[0054] After filling, the cleaning fluid 18 filled into pipe 2 is in contact with the pipe wall section 5 of pipe wall 3. If the Figure 1If the cleaning device 8 shown is used to clean the system 1, a liquid comprising water, for example, is used as the cleaning fluid 18. Preferably, the cleaning fluid 18 also comprises a cleaning agent such as a surfactant. After filling the pipeline 2 with the cleaning fluid 18, the pressure modulation chamber 10 of the cleaning device 8 is fluidically connected to the interior 5 of the pipeline 2. Because the cleaning fluid 18 is located in the interior 5, the pressure modulation chamber 10 is also fluidically connected to the cleaning fluid 18. Alternatively, instead of the procedure described above, the pressure modulation chamber 10 is first fluidically connected to the interior 5 of the pipeline 2. Only then is the pipeline 2 filled with the cleaning fluid 18.

[0055] If the pipeline 2 is filled with the cleaning fluid 18 and the pressure modulation chamber 10 is fluidically connected to the cleaning fluid 18, the cleaning fluid 18 is heated by the heating device 6. The drain valve 15 is closed, so that the pressure modulation chamber 10 is fluidically sealed from the surroundings. The heating of the cleaning fluid 18 therefore causes the pressure in the pressure modulation chamber 10 to rise and then exceed the ambient pressure. Preferably, the cleaning fluid 18 is heated to a temperature that exceeds its boiling point at ambient pressure. A saturated vapor equilibrium is established in the pressure modulation chamber 10. The saturated liquid (liquid phase) is in equilibrium with saturated vapor (gas phase) of the same substance before the pressure pulsation.Following the pressure drop, which will be described in more detail below, some of the liquid evaporates (spontaneous boiling) in the form of vapor bubbles. After this boiling process, caused by the pressure drop, has ended, a new saturated vapor equilibrium is established. For example, the water-containing cleaning fluid 18 is heated to a temperature of 120 °C. A pressure of approximately 2.0 bar is then established in the pressure modulation chamber 10.

[0056] Following the increase in pressure in pressure modulation chamber 10, the pressure in pressure modulation chamber 10 is abruptly reduced. During the process in Figure 1In the illustrated embodiment, the pressure is reduced by opening the drain valve 15. When the drain valve 15 is open, the gas in the pressure modulation chamber 10 is released from the pressure modulation chamber 10 into the environment. Due to the fluidic connection with the cleaning fluid 18, the pressure of the cleaning fluid 18 is also reduced by the reduction of the pressure in the pressure modulation chamber 10. This causes gas bubbles 19 to form in the cleaning fluid 18. As can be seen from the upper right figure of the Figure 6 As can be seen, the gas bubbles 19 form more frequently at the crack 16 and the contamination 17. The gas bubbles 19 adhere to the contamination 17 and lift the contamination 17 from the pipe wall section 5. Preferably, the pressure in the pressure modulation chamber 10 is increased again after the pressure has been lowered. In the case of the Figure 1In the manufactured embodiment of the cleaning device 8, the pressure is increased by closing the drain valve 15 and introducing further cleaning fluid 18. The increase in pressure in the pressure modulation chamber 10 also increases the pressure in the cleaning fluid 18. This causes the gas bubbles 19 to implode or collapse after their formation. The collapse of the gas bubbles 19 enhances the cleaning effect. Preferably, several cleaning cycles are performed in the form of pressure pulsations, in which the pressure in the pressure modulation chamber 10 is lowered and then subsequently increased again.

[0057] Figure 2 Annex 1 shows the cleaning device 8 according to a further embodiment. In the case of the Figure 2In the illustrated embodiment of the cleaning device 8, the means 14 comprise a pump 20. A suction side of the pump 20 is fluidically connected to the pressure modulation chamber 10. A pressure side of the pump 20 is fluidically connected to the environment. The pump 20 is thus designed to pump a gas located in the pressure modulation chamber 10 out of the pressure modulation chamber 10 into the environment. If the system 1 is operated by the in Figure 2 When the cleaning device 8 shown is cleaned, the pressure in the pressure modulation chamber 10 is reduced by the pump 20. This also causes the gas bubbles 19 to form in the cleaning fluid 18 and the pipe wall section 5 to be cleaned. Heating the cleaning fluid 18 by the heating device 6 is optional. Preferably, the pressure in the pressure modulation chamber 10 is increased again after the pressure has been reduced. In the case of the Figure 2In the illustrated embodiment, the pressure is increased, for example, by opening a vent valve (not shown) that acts between the pressure modulation chamber 10 and the environment. This also applies to the embodiment described in Figure 2 In the illustrated embodiment, a cleaning fluid 18 comprising water is preferably used.

[0058] Figure 3 Annex 1 shows the cleaning device 8 according to a further embodiment. In the case of the Figure 3In the illustrated embodiment, the means 14, in addition to the drain valve 15, comprise a container 21 with a drain chamber 22. The drain valve 15 acts between the pressure modulation chamber 10 and the drain chamber 22. The means 14 also comprise a pump 23 associated with the drain chamber 22. A suction side of the pump 23 is fluidically connected to the drain chamber 22. A pressure side of the pump 23 is fluidically connected to the environment. The pump 23 is designed to pump a gas located in the drain chamber 22 out of the drain chamber 22 into the environment. If the system 1 is operated by the in Figure 3The cleaning device 8 shown is cleaned. Before the pressure in the pressure modulation chamber 10 is lowered, the pressure in the drain chamber 22 is reduced by the pump 23 so that the pressure in the drain chamber 22 falls below the pressure in the pressure modulation chamber 10. The drain valve 15 is then opened. The gas in the pressure modulation chamber 10 is then released into the drain chamber 22, resulting in a sudden drop in pressure in the pressure modulation chamber 10 and in the cleaning fluid 18. Gas bubbles 19 form in the cleaning fluid 18, thereby cleaning the pipe wall 3. Heating the cleaning fluid 18 by the heating device 6 is optional. Preferably, the pressure in the pressure modulation chamber 10 is increased again after the pressure has been lowered. Figure 3In the illustrated embodiment, the pressure is increased, for example, by opening a vent valve (not shown) that acts between the pressure modulation chamber 10 and the environment. The Figure 3 The cleaning device 8 shown offers, compared to the one in Figure 2 The cleaning device 8 shown has the advantage that a less powerful pump 23 can be used, because the sudden drop in pressure in the pressure modulation chamber 10 is not directly generated by the operation of the pump 23.

[0059] Figure 4 Annex 1 shows the cleaning device 8 according to a further embodiment. In the case of the Figure 4 In the illustrated embodiment, the means 14 comprise a metering device 24 for spraying liquid into the pressure modulation chamber 10. In particular, several metering devices 24 are provided. If the system 1 is equipped with the device described in Figure 4After cleaning the cleaning device 8 shown, the pressure modulation chamber 10 is first enriched with vaporous cleaning fluid 18. For this purpose, the cleaning fluid 18 is preferably heated by the heating device 6 to a temperature lower than its boiling point at ambient pressure. The saturated vapor pressure of the cleaning fluid 18 in the pressure modulation chamber 10 is then below the ambient pressure. Subsequently, cooled cleaning fluid 25 is sprayed into the pressure modulation chamber 10 by means of the metering device 24, thereby finely atomizing the cooled cleaning fluid 25. The vaporous cleaning fluid 18 in the pressure modulation chamber 10 condenses on the cooled cleaning fluid 18, leading to a sudden drop in pressure in the pressure modulation chamber 10, so that gas bubbles 19 are formed in the cleaning fluid 18.Preferably, the pressure in the pressure modulation chamber 10 is increased again after the pressure has been lowered. In the case of... Figure 4 In the cleaning device 8 shown, the pressure is increased, for example, by opening a vent valve (not shown) that acts between the pressure modulation chamber 10 and the environment. Alternatively, gas or liquid can be pumped into the pressure modulation chamber 10 to increase the pressure. The in Figure 4 The cleaning device 8 shown has the advantage that the cleaning fluid 18 does not escape into the environment. Therefore, in the case of the Figure 4The cleaning device 8 shown also allows the use of a cleaning fluid 18 comprising at least one organic solvent without any problems. Preferably, the cleaning device 8 is arranged above the pipeline 2 such that the cleaning fluid 18, which condenses in the pressure modulation chamber 10, flows back into the pipeline 2 under the influence of gravity.

[0060] Figure 5 Annex 1 shows the cleaning device 8 according to a further embodiment. In the case of the Figure 4 In the illustrated embodiment, the means 14 comprise a heat exchanger 26, which is designed to cool the pressure modulation chamber 10. If the system 1 is operated by the means shown in Figure 5After cleaning the cleaning device 8 shown, the pressure modulation chamber 10 is first enriched with vaporous cleaning fluid 18. For this purpose, the cleaning fluid 18 is preferably heated by the heating device 6 to a temperature lower than its boiling point at ambient pressure. The saturated vapor pressure of the cleaning fluid 18 in the pressure modulation chamber 10 is then below the ambient pressure. Subsequently, the pressure modulation chamber 10 is rapidly cooled by the heat exchanger 26. The vaporous cleaning fluid 18 in the pressure modulation chamber 10 condenses on the cooled heat exchanger 26, leading to a rapid drop in pressure in the pressure modulation chamber 10, causing the gas bubbles 19 to form in the cleaning fluid 18. Preferably, the pressure in the pressure modulation chamber 10 is increased again after the pressure drop. Figure 5In the cleaning device 8 shown, the pressure is increased, for example, by opening a vent valve (not shown) which acts between the pressure modulation chamber 10 and the environment. Also, the Figure 5 The illustrated cleaning device 8 has the advantage that the cleaning fluid 18 cannot escape into the environment. Preferably, the cleaning device 8 is arranged above the pipeline 2 such that the cleaning fluid 18, which has condensed in the pressure modulation chamber 10, flows back into the pipeline 2.

[0061] In the Figures 1 to 5 In the illustrated embodiments, the pressure modulation chamber 10 is always part of the cleaning device 8, which can be handled independently of the system 1.

[0062] Figure 7Figure 1 shows a system 1 with an injection device 27. The injection device 27 is connected to the drain chamber 22 via a line 28 and a valve 29. The gas, which was released from the pressure modulation chamber 10 into the drain chamber 22 during pressure reduction, can be fed to a compressor 30 via the line 28 and the valve 29. From the compressor 30, it is fed in compressed form to the injection device 27, through which it can be fed back into the pipeline 2. Due to the previous compression, it dissolves again in the cleaning fluid, and the pressure in the pipeline 2 and the pressure modulation chamber 10 rises again. The valve 15 to the drain chamber 22 is closed to prevent a drop in pressure.

[0063] Fig. 8Figure 1 illustrates a method used for cleaning objects 32 (e.g., electronic components). The objects 32 to be cleaned were placed in a cleaning chamber 34 of a cleaning unit 36. The cleaning chamber 34 is filled with a cleaning fluid 38. The objects 32 are located, as shown in Figure 2, in the cleaning chamber 34. Fig. 8 illustrated, i.e., in the cleaning fluid. The cleaning chamber 34 is pressure-tight and sealable. The cleaning chamber 34 is fluidically connected to a pressure modulation chamber 10 via a valve 48.

[0064] The procedure includes step 42: placing at least one item 32 to be cleaned in the cleaning room 34.

[0065] The process includes step 44: reducing the pressure in the cleaning chamber 34, which contains the cleaning fluid 38 and the items to be cleaned. This causes gas bubbles 40 to form in the cleaning fluid 38. The gas bubbles 40 clean the items 32 to be cleaned. In particular, some of the gas bubbles 40 collapse after their formation. Cavitation, i.e., the formation and sudden collapse of gas bubbles 40, can occur during the cleaning process.

[0066] In the present example, the process further includes step 46: drying the objects, e.g. by means of IR radiation, microwave radiation and / or heat conduction and / or freeze-drying.

[0067] The cleaning fluid 38 can be designed like the cleaning fluid 18 already described. In particular, it can comprise an organic solvent and a volatile component dissolved therein.

Claims

1. Method for cleaning wall portions (5) of liquid-conducting regions (2) which are designed as pipelines (2) and / or fittings of an installation (1), in particular a processing, chemical, food or pharmaceutical installation, wherein at least one liquid-conducting region (2) to be cleaned of the installation (1) is filled with a cleaning liquid (18), wherein the region (2) to be cleaned, which is filled with cleaning liquid (18), is fluidically connected to a pressure modulation chamber (10), wherein, after filling with the cleaning liquid (18), the pressure in the pressure modulation chamber (10) is reduced, so that, by means of the fluidic connection to the cleaning liquid (18) in the region (2) to be cleaned, the pressure of the cleaning liquid (18) reduces and gas bubbles (19) are formed in the cleaning liquid (18), by means of which the wall portion (5) of the region (2) to be cleaned is cleaned, in particular wherein at least some of the gas bubbles (19) collapse again after their formation, in particular wherein the gas bubbles (19) are formed by spontaneous boiling caused by the pressure reduction, and / or wherein the gas bubbles (19) are formed by outgassing of a substance dissolved in the cleaning liquid (18), wherein the outgassing is caused by the pressure reduction, characterized in that the pressure modulation chamber (10) is provided at least partially in a cleaning device (8) that can be handled independently of the installation (1).

2. Method according to any of the preceding claims, characterized in that, prior to the pressure reduction, the pressure modulation chamber (10) is at least partially filled with gas.

3. Method according to any of the preceding claims, characterized in that, prior to the reduction, the pressure in the pressure modulation chamber (10) exceeds the ambient pressure.

4. Method according to any of claims 2 and 3, characterized in that the pressure in the pressure modulation chamber (10) is reduced by discharging gas located in the pressure modulation chamber (10) from the pressure modulation chamber (10), in particular wherein the gas is discharged into the environment or into a discharge chamber (22) that is closed with respect to the environment, in particular wherein, prior to discharging into the discharge chamber (22), a negative pressure is present in the discharge chamber.

5. Method according to any of the preceding claims, characterized in that, after the region (2) to be cleaned is filled, the cleaning liquid (18) is heated, in particular wherein the heating is brought about by means of a heat exchanger and / or by steam injection.

6. Method according to any of claims 2 to 5, characterized in that, prior to the reduction, the gas located in the pressure modulation chamber (10) is predominantly vaporous cleaning liquid (18), in particular wherein the pressure in the pressure modulation chamber (10) is reduced by means of an, in particular sudden, condensation of the vaporous cleaning liquid (18) in the pressure modulation chamber (10).

7. Method according to any of the preceding claims, characterized in that the pressure in the pressure modulation chamber (10) is reduced by cooling the pressure modulation chamber (10).

8. Method according to claim 7, characterized in that the pressure modulation chamber (10) is cooled by means of spraying cooled cleaning liquid (25) into the pressure modulation chamber (10), in particular wherein the cleaning liquid (25) is atomized during spraying.

9. Method according to claim 7 or 8, characterized in that the pressure modulation chamber (10) is cooled by means of a heat exchanger (26).

10. Method according to any of the preceding claims, characterized in that the pressure in the pressure modulation chamber (10) is reduced by means of a pump (20).

11. Method according to any of the preceding claims, characterized in that a liquid enriched with a gas is used as the cleaning liquid (18).

12. Method according to any of the preceding claims, characterized in that a water-containing liquid is used as the cleaning liquid (18) and / or in that a liquid comprising at least one organic solvent is used as the cleaning liquid (18).

13. Method according to any of the preceding claims, characterized in that the pressure in the pressure modulation chamber (10) is increased again after the reduction, in particular in order to encourage the gas bubbles (19) formed by the pressure reduction to collapse.