Method for cleaning and checking line systems

Abstract

The invention relates to a method for cleaning and / or checking line systems (10), in particular branched line systems (10), which have dead volumes (11) as a result of branches, valves, controllers or sensors, comprising one, a plurality or all of the following steps: 1) mobilising contaminants within the line system (10); 2) cleaning the line system (10) to eliminate the contaminants; 3) checking the purity of the line system (10), wherein the mobilisation is carried out by means of evacuating, applying heat, applying electromagnetic radiation, induction, applying vibration or combinations of the above-mentioned measures.

Description

[0001] Procedures for cleaning and inspecting piping systems

[0002] The invention relates to a method for cleaning and / or inspecting piping systems.

[0003] Piping systems are used in a wide variety of industries, such as pharmaceuticals, semiconductors, food, and biotechnology. However, these systems must meet the highest purity and hygiene standards.

[0004] For example, in the semiconductor industry, it is common practice to use corrosive and / or toxic gases, as well as otherwise harmless gases that can be activated by electron bombardment, to treat surfaces, as these are required for fundamental processes such as etching, coating, or doping. Such processes are generally carried out under vacuum in appropriate process chambers to create highly pure working conditions and prevent any contamination. The gases used must therefore also be highly pure to avoid impurities, such as particles, water, and / or organic compounds, in the process chamber and ultimately in the resulting products.

[0005] Such high-purity gases are typically supplied by specialized gas cabinets, which enable the safe storage of harmless, as well as corrosive and toxic substances. These gas cabinets have brackets and connections for compressed gas cylinders. They may also include vaporizers that convert liquids and solids into the gaseous phase, allowing the chemicals in question to be supplied to the system in gaseous form. User safety when handling potentially hazardous substances is generally ensured by an integrated exhaust system that is regularly inspected. Overall, such gas cabinets comprise a multitude of lines, valves, regulators, and sensors, resulting in a complex, branched piping system.

[0006] Ideally, the cleaning of such linear or branched piping systems is carried out without disassembling the system. To remove any organic and inorganic contaminants, and for disinfection necessary in some applications, the system is typically flushed using alkalis, acids, and / or hot water or steam. It is known to use the so-called TOC (total organic compounds) method for the subsequent quality testing of such piping systems to determine the total concentration of organic carbon. Alternatively or complementarily, sorbent tube analysis can also be used. For this, a known quantity of purge gas, for example, XCDA (extremely clean dry air), is passed through the system to be tested and then through a sorbent / sample tube containing adsorption material, onto which the organic compounds adsorb.The contents of the sample tube are then analyzed, for example, using GC-MS (gas chromatography coupled with mass spectrometry).

[0007] Even after such cleaning and inspection of pipe systems, it can be observed that systems deemed clean may still be a source of unwanted contaminants, which can negatively impact downstream processes. This is particularly problematic in branched pipe systems.

[0008] The object of the invention is to provide a method for cleaning and / or checking piping systems, which makes it possible to remove contaminants in piping systems, especially in branched piping systems, more efficiently and to check their purity with increased precision.

[0009] The problem is solved by a method having the features of claim 1.

[0010] Advantageous further training courses are marked in the sub-requirements.

[0011] In contrast to a linear piping system, a branched piping system is a piping system that has branches and additional components such as valves, controllers and sensors.

[0012] The inventors recognized that the remaining impurities in branched piping systems after treatment using state-of-the-art methods are largely attributable to the branch points of the piping system and additional components such as valves, regulators, and sensors. These lead to dead volumes in the system, in which impurities, for example organic compounds, can accumulate.

[0013] These hard-to-reach contaminants cannot be reached and removed by conventional cleaning methods such as rinsing with alkalis, acids, and / or hot water or steam. Furthermore, it is difficult to detect these contaminants during cleanliness testing, as they cannot be mobilized by purge gas and therefore cannot be detected and analyzed. Thus, while conventional cleaning techniques and validation methods, such as sorbent tube analysis or the TOC method, are effective for linear piping systems, they appear unsuitable for cleaning and verifying complex, branched piping systems.

[0014] To counteract this problem, the inventors have developed a novel method for cleaning and / or inspecting piping systems, especially branched piping systems with dead volumes. This method comprises the following steps:

[0015] 1) Mobilization of contaminants;

[0016] 2) Cleaning;

[0017] 3) Checking the purity.

[0018] In the first step, the sometimes very difficult-to-access contaminants are mobilized using suitable methods, such as evacuation. Mobilization here refers to the application of targeted stimulating methods to encourage and promote desorption from the surface and / or diffusion from the volume of contaminants, so that even difficult-to-access contaminants become accessible for cleaning and / or inspection.

[0019] For example, during evacuation, the piping system is first sealed and then evacuated using a vacuum pump. This causes the contaminants adsorbed onto the walls of the piping system to be transferred into the gas phase and mobilized due to their vapor pressure. This applies to both the linear sections of the piping system and any dead volumes such as branches, valves, regulators, or sensors, from which contaminants are then transported to more accessible areas of the piping system. A similar effect can also be achieved, for example, by applying heat and / or vibration.

[0020] In the second step, the mobilized contaminants are removed from the piping system for cleaning. This can be achieved, for example, by pulse evacuation and / or alternating pressure flushing with inert and / or reactive purge gas. For instance, a unidirectional pressure flush of the branched piping system with a purge gas can be used, whereby the purge gas is forced under pressure through the branched piping system along a predetermined direction, carrying away and removing a large proportion of the previously mobilized contaminants present in the system. The prior mobilization has the advantageous effect of enabling more efficient cleaning in the second step, as contaminants that are otherwise difficult to access can also be removed from branches and dead volumes of the piping system.

[0021] In the third step, purity is verified using established measurement methods such as sorbent tube analysis, residual gas analysis (RGA), and / or real-time VOC analysis. Sorbent tube analysis is the preferred method, in which the exhaust gas (evacuation) or purge gas stream (pressure purge), which carries the contaminants from the system, is passed through a test tube, such as a Carbotrap tube, which captures the contaminants. Subsequently, a qualitative and quantitative analysis of the organic compounds contained in the tube is performed, for example, using GC-MS. Of course, verification can also be carried out directly after mobilization without intermediate purification.The prior mobilization makes it possible to detect and analyze otherwise difficult-to-access contaminants from branches and dead volumes of the pipe system.

[0022] It is understood that, for the purposes of the invention, the three steps above can be carried out sequentially. However, only the first and second steps or the first and third steps can also be performed if only cleaning or inspection of the piping system is required. It is also possible for the mobilization (step 1) to be carried out both before or during the cleaning (step 2) and before or during the inspection of the cleanliness (step 3).

[0023] Alternatively or in addition to evacuation, further measures can be taken to mobilize the contaminants in step 1 in order to increase their mobility and thereby improve the efficiency of the process. These include, for example, the application of heat, electromagnetic radiation, induction, and / or vibration.

[0024] Evacuation, through reduced pressure, helps to transfer volatile and non-volatile substances, as well as contaminants adsorbed onto the walls of the piping system, into the gas phase, mobilize them, and remove them. The duration of the evacuation depends heavily on the dimensions and geometry of the piping system and the amount of contaminants within it. To achieve a defined target pressure, for example, ICT (Internal Pressure Control), a specific pressure is reached. 5To achieve a pressure of mbar, a branched piping system with dead volumes will require significantly longer evacuation than a linear piping system. It is particularly advantageous to evacuate the piping system at lower pressures than those intended for its subsequent use, as this ensures that no unwanted contamination occurs during operation, for example, through outgassing of the piping material. Before evacuation, it should, of course, be verified that all materials and components of the piping system are vacuum-stable.

[0025] Applying heat to the piping system increases the volatility of organic compounds, thus facilitating their desorption from the system walls and mobilizing the contaminants. The required temperature depends heavily on the materials used in the piping system. For example, very high temperatures of several hundred °C are possible for stainless steel piping systems. However, if the piping system contains electronic components such as controllers or sensors, the heating temperature must be significantly reduced (< 100 °C). It is essential to set the heating temperature so that material properties are not altered and any additional components are not damaged. The required heating duration also depends heavily on the dimensions and geometry of the piping system and the amount of contaminants present. Generally, the larger the system, the longer the heating time.The more branched or contaminated the pipe system is, the longer the heating process must be to achieve a sufficient mobilization effect.

[0026] Applying vibration is particularly helpful in removing contaminants from the surfaces of pipe systems. The applied frequency should be carefully selected to avoid damaging the components within the system. Furthermore, the frequency may be limited by the dimensions of the pipe system. Very large pipe systems may not fit in standard ultrasonic baths and are therefore treated using mechanical vibration platforms. However, these platforms operate at a much lower frequency (Hz range) than ultrasonic baths (kHz range). The required treatment duration for vibration also depends heavily on the dimensions and geometry of the pipe system and the amount of contaminants present.Generally speaking, the larger and / or more branched and / or more contaminated the vascular system is, the longer the treatment must last to achieve a sufficient mobilization effect.

[0027] Similarly, measures such as exposure to electromagnetic radiation or induction also help to mobilize and remove contaminants from the pipe system. Here, too, system-specific parameters must be selected to ensure a sufficient effect and to prevent damage to the pipe system and its components.

[0028] The selection of appropriate parameters for the above mobilization measures can be easily accomplished by a specialist with knowledge of the respective specifications of the relevant pipeline system.

[0029] The significant advantage of the invention lies in the mobilization process, which makes difficult-to-access contaminants from branches and dead volumes of the piping system accessible for cleaning and inspection. Overall, following mobilization, contaminants in the branched piping system are thus removed more efficiently and / or more completely captured.

[0030] A piping system cleaned and / or inspected using the method according to the invention is ultimately suitable for conveying high-purity gases and liquids in demanding processes in the pharmaceutical, semiconductor, food or biotechnology industries, since these are no longer contaminated by the piping system itself.

[0031] The invention thus relates to a method for cleaning and / or inspecting piping systems, in particular branched piping systems which have dead volumes, in particular due to branches, valves, regulators or sensors, comprising one, several or all of the following steps:

[0032] 1) Mobilization of contaminants within the pipeline system;

[0033] 2) Cleaning of the piping system to remove the contaminants;

[0034] 3) Checking the cleanliness of the piping system,

[0035] Mobilization is carried out by means of evacuation, application of heat, application of electromagnetic radiation, induction, application of vibration or combinations of the aforementioned measures.

[0036] The invention therefore relates in particular to a method for cleaning and / or inspecting piping systems, especially branched piping systems, which have dead volumes, in particular due to branches, valves, regulators or sensors, comprising the following steps: 1) Mobilization of contaminants within the piping system; and / or

[0037] 2) Cleaning of the piping system to remove the contaminants; and / or

[0038] 3) Checking the cleanliness of the piping system,

[0039] Mobilization is carried out by means of evacuation, application of heat, application of electromagnetic radiation, induction, application of vibration or combinations of the aforementioned measures.

[0040] Mobilization prior to cleaning and / or inspection is of immense importance, particularly for branched piping systems which have dead volumes and consequently difficult-to-access contaminants, as conventional methods fail in these cases. The inventive method is also advantageous for linear piping systems because mobilization enables reliable cleaning and inspection, even when relatively low gas flow rates (e.g., 50 sccm) are used for pressure (cycling) purging or sorbent tube analysis.

[0041] In particular, the combination of evacuation and the application of heat can have a particularly beneficial effect with regard to the mobilization of contaminants, as this greatly promotes the outgassing of the materials and components installed in the piping system.

[0042] An advantageous further training method provides that cleaning is carried out using pressure flushing, pressure alternating flushing, evacuation, pulse evacuation or combinations of the aforementioned measures.

[0043] Pulse evacuation involves a rapid pressure change (alternating between vacuum and atmospheric pressure) to physically dislodge and extract particles and volatile substances. Atmospheric pressure is achieved by introducing air or a purge gas. The duration and number of individual cycles depend on the dimensions, geometry, and degree of contamination of the piping system. Pulse evacuation is particularly effective for cleaning porous or occluded surfaces.

[0044] In a pressure flush, contaminants are flushed from the surfaces of the piping system and ultimately out of the system using a reactive or inert flushing gas introduced under overpressure. Such a pressure flush can also be performed as a pressure swing flush, in which – similar to pulse evacuation – a rapid pressure change (alternating between atmospheric pressure and overpressure) is carried out to dislodge more contaminants in the gas stream and achieve even more efficient cleaning.

[0045] An advantageous further training provides that the purity check is carried out using sorbent tube analysis, residual gas analysis, real time VOC analysis, TOC analysis or combinations of the aforementioned methods.

[0046] An advantageous further training stipulates that during the evacuation a pressure < 10 3 mbar, preferably < 10 3 mbar, especially preferably < 10' 5mbar is reached.

[0047] An advantageous further development provides that the evacuation is carried out by means of one or more vacuum pumps, wherein the vacuum pumps include rotary vane pumps, diaphragm pumps, screw pumps, ion getter pumps, titanium sublimation pumps, turbomolecular pumps, scroll pumps, piston pumps, diffusion pumps, cryopumps or combinations of the aforementioned.

[0048] Alternatively, if the dimensions allow, the evacuation piping system can also be placed in a vacuum chamber.

[0049] An advantageous further development provides that, in the course of applying heat, a temperature > 30 °C, preferably > 60 °C, particularly preferably > 90 °C is reached.

[0050] An advantageous further development provides that the application of heat is carried out by means of one or more heating devices, the heating devices including fan heaters, heating blankets, heating tents, heating tapes, heating chambers, ovens and combinations of the aforementioned.

[0051] An advantageous further development provides that, in the course of being subjected to vibration, a frequency between 1 Hz and 100 kHz, preferably between 30 Hz and 80 kHz, and particularly preferably between 60 Hz and 40 kHz, is achieved.

[0052] An advantageous further development provides that the application of vibration is carried out using an ultrasonic bath, a mechanical vibration platform or a combination of the aforementioned.

[0053] A beneficial advanced training method involves using an inert and / or reactive purge gas for pressure flushing or pressure swing flushing. Reactive purge gases offer the advantage of reacting with contaminants and converting them into compounds that are easier to remove. For example, ozone can be used as a reactive purge gas, which oxidizes and breaks down organic contaminants. However, such reactive purge gases require increased caution when handling them. Furthermore, materials or components of the piping system must not be attacked or damaged by the reactive purge gas.

[0054] An advantageous further development provides that the purge gas is selected from the group comprising XCDA, nitrogen, noble gases, carbon dioxide, oxygen, ozone, hydrogen peroxide, chlorine, hydrogen and combinations of the aforementioned.

[0055] Carbon dioxide can also be used in so-called "CO2 snow cleaning." In this process, liquid CO2 is introduced into the system to be cleaned, where it freezes and removes the contaminants. This method is suitable, for example, for sensitive surfaces, as it is non-abrasive and leaves no residue.

[0056] An advantageous further development stipulates that the purge gas is a reactive plasma.

[0057] An advantageous further development provides that a flow rate > 1 sccm, preferably > 10 sccm, particularly preferably > 30 sccm or > 50 sccm is achieved during pressure flushing or pressure alternating flushing.

[0058] An advantageous further training procedure provides that the evacuation and / or pressure flushing is carried out bidirectionally from two different sides of the piping system.

[0059] To increase the mobility of the contaminants in the piping system, thereby ultimately facilitating or even enabling their removal from the system by vacuum pumps or pressurized gas purging, a bidirectional evacuation and / or pressurized purging can be carried out according to the invention in such a way that a kind of oscillation of the gas column in the system results with or without significant gas discharge.

[0060] The invention is explained by way of example with the aid of a drawing. The drawing shows:

[0061] Fig. 1: a highly schematic representation of a prior art gas cabinet which provides high-purity process gases for surface treatment in a high-vacuum process chamber; Fig. 2: a highly schematic representation of the prior art application of sorbent tube analysis in a linear piping system;

[0062] Fig. 3: a highly schematic representation of the application of Sorbent Tube Analysis according to the state of the art in a branched pipe system;

[0063] Fig. 4: a highly schematic representation of an exemplary embodiment of the invention, comprising the steps of heating, evacuation and sorbent tube analysis for checking a branched piping system;

[0064] Fig. 5: Diagrams showing temperature, pressure and flow rate as a function of time for the exemplary embodiment of the invention shown in Figure 4;

[0065] Fig. 6: a highly schematic representation of an exemplary embodiment of the invention, comprising the steps of heating, evacuation and pressure flushing for cleaning a branched piping system.

[0066] Figure 1 shows a highly schematic representation of a gas cabinet 1 that supplies high-purity process gases to a high-vacuum process chamber 2. The process gases are fed to the high-vacuum process chamber 2 via gas supply lines 3 and introduced into the high-vacuum process chamber 2 through a gas outlet 4. There, they are used in a highly purified form for the treatment and / or coating of surfaces 5.

[0067] To prevent contamination of the system and the products manufactured within it, for example by particles, water, or organic compounds, process gases must be of highly pure form. However, it has been found that, according to the state of the art, cleaned and inspected, particularly branched, piping systems such as those part of the gas cabinet and the supply system, do not meet industrial requirements and lead to the introduction of undesirable contaminants.

[0068] According to the state of the art, such piping systems are inspected, for example, using sorbent tube analysis. Figure 2 shows a highly schematic representation of the application of this method to a linear piping system 6. A purge gas is introduced into the linear piping system 6 via a gas inlet 7 and a valve 8. This gas flows through the system 6, carrying impurities, particularly organic compounds, with it. After exiting the piping system 6, this purge gas stream is passed through a Carbotrap test tube 9 and then discharged as exhaust air. The organic compounds adsorbed in the test tube 9 are then analyzed by GC-MS.The inventors discovered that, unlike linear systems, the dead volumes present in branched piping systems—caused by branches and additional components such as valves, regulators, and sensors—are the reason for the undesirable contamination observed in branched piping systems tested according to the prior art. This is due to the accumulation of organic compounds, for example, which cannot be detected by sorbent tube analysis.

[0069] Figure 3 shows a highly schematic representation of the application of this method in a branched piping system 10. It can be seen that contaminants that are difficult to access and located in dead volumes 11 are not mobilized by the purge gas flow that is passed through the system during the sorbent tube analysis and therefore do not reach the test tube 9, meaning that these contaminants cannot be analyzed.

[0070] This problem can be solved by the method according to the invention. An exemplary embodiment of the invention, comprising the steps of mobilization and verification, is shown in a highly schematic form in Figure 4.

[0071] In this embodiment, the branched piping system 10 is first heated to 60 °C for 1 hour, for example in an oven. This step is important to desorb any volatile and non-volatile impurities from the surfaces of the piping system 10 or to remove them from the volume of the material of the piping system 10. The impurities thus mobilized can then be more easily removed in subsequent steps.

[0072] After heating, the piping system 10 is evacuated in a second step. For this purpose, the piping system 10 is fitted with a closed valve 8 at the inlet, which in turn serves as the interface to the gas inlet 7. A Carbotrap test tube 9 is also attached at the outlet, and a vacuum pump 12 is connected via a three-way valve 13. For evacuation, the vacuum pump 12 is activated, and the three-way valve 13 is opened only towards the vacuum pump. The evacuation phase lasts approximately 1 hour. The contaminants mobilized by the preceding heating and pressure reduction are flushed out of all parts of the system 10, including the hard-to-reach dead volumes 11, and passed through the test tube 9, where they are absorbed.

[0073] After evacuation, the vacuum pump 12 is switched off, and the three-way valve 13 is closed towards the vacuum pump 12 and opened towards the exhaust air. In a third step, the actual inspection is then carried out using sorbent tube analysis. For this purpose, the inlet valve 8 is opened, and XCDA is introduced as a purge gas at a flow rate of 50 sccm for 20 minutes through the piping system 10. The purge gas removes the impurities remaining in system 10 after evacuation, which were mobilized by the preceding heating and evacuation process, and these impurities are absorbed in the test tube 9. The organic compounds adsorbed in the test tube 9 during evacuation and pressure purging are then quantitatively and qualitatively analyzed using suitable methods such as GC-MS or thermal desorption.The measures according to the invention allow, as described above, impurities from the difficult-to-access dead volumes 11 to be detected and analyzed. This results in a more precise quantification of the impurities during the inspection of the piping system 10. This is invaluable for making qualified statements about the cleanliness of the piping system 10.

[0074] Overall, the multi-stage procedure results in an efficient and comprehensive inspection of the branched piping system 10. A piping system 10 inspected in this way would then, if its purity is confirmed, also be suitable for conveying high-purity process gases, such as those used in a high-vacuum process chamber 2, since these would no longer be contaminated by the piping system itself, for example by impurities trapped within valves.

[0075] Figure 5 illustrates the process flow in the exemplary embodiment according to Figure 4 in three diagrams showing temperature (top), pressure (middle), and flow rate (bottom) as a function of time. Regarding temperature, the top diagram shows that in the first step (heating), the system is heated to 60 °C for 1 hour. Afterwards, the temperature drops back to a constant level (room temperature). The middle diagram shows the pressure flow, according to which, in the second step (evacuation), a pressure of < 10°C is maintained for 1 hour. 4 The pressure is set to mbar. In the third step, as can be seen from the diagram below, the pipe system 10 is flushed with a flow rate of 50 sccm for 20 min as part of the Sorbent Tube Analysis XCDA.

[0076] An exemplary embodiment of the invention, comprising the steps of mobilization and cleaning, is shown in a highly schematic form in Figure 6.

[0077] In this embodiment, the branched piping system 10 is first heated to 60 °C for 1 hour, for example in an oven. This step is important to desorb any volatile and non-volatile impurities from the surfaces of the piping system 10 or to remove them from the volume of the material of the piping system 10. The impurities thus mobilized can then be more easily removed in subsequent steps.

[0078] After heating, the piping system 10 is evacuated in a second step. For this purpose, the piping system 10 is fitted with a closed valve 8 at the inlet, which in turn serves as the interface to the gas inlet 7. A vacuum pump 12 is also connected at the outlet via a three-way valve 13. For evacuation, the vacuum pump 12 is activated, and the three-way valve 13 is opened only towards the vacuum pump. The evacuation phase lasts approximately 1 hour. The impurities mobilized by the preceding heating and the pressure reduction are flushed out and pumped out of all parts of the system 10, including the hard-to-reach dead volumes 11.

[0079] After evacuation, the vacuum pump 12 is switched off and the three-way valve 13 is closed towards the vacuum pump 12 and opened towards the exhaust air. In a third step, a pressure purge is then carried out using XCDA as the purge gas. For this purpose, the inlet valve 8 is opened and XCDA is passed through the piping system 10 under overpressure (5 bar) to flush out the contaminants remaining in the system 10 after evacuation, which were mobilized by the preceding heating and evacuation, via the three-way valve 13.

[0080] Here, evacuation and pressure flushing are used to clean the branched piping system 10. These two steps can be repeated as needed to achieve pressure-cycling flushing or pulse evacuation and to clean the piping system 10 even more thoroughly. In cases of severe contamination of the piping system 10, pressure flushing with reactive purge gas can also be performed for improved cleaning effectiveness.

[0081] After cleaning, the piping system 10 can be checked using the sorbent tube analysis, as described above for the exemplary embodiment shown in Figure 4.

[0082] The method according to the invention can be used, for example, for checking branched piping systems or parts of a branched piping system that have a dead volume for impurities. The parts of the branched piping system that have a dead volume are, for example, branches, valves, regulators, or sensors. The invention enables efficient cleaning and / or precise inspection of piping systems, especially branched piping systems, by allowing impurities, particularly organic compounds, to be removed more efficiently and detected more completely. A piping system cleaned and / or inspected according to the invention is particularly advantageous when conveying high-purity process gases, since impurities, especially organic compounds, are completely avoided or reduced to an acceptable minimum. [Reference numeral list]

[0083] 1 gas cabinet

[0084] 2 high-vacuum process chambers, 3 gas supply lines

[0085] 4 Gas outlet

[0086] 5 surfaces

[0087] 6 linear piping system

[0088] 7 Gas Inlet

[0089] 8 valve

[0090] 9 Carbotrap test tubes

[0091] 10 branched piping system 11 dead volumes

[0092] 12 Vacuum pump

[0093] 13 Three-way valve

Claims

Claims 1. Method for cleaning and / or checking piping systems (6, 10), in particular branched piping systems (10), which have dead volumes (11), in particular due to branches, valves, regulators or sensors, comprising one, several or all of the following steps: 1) Mobilization of contaminants within the pipeline system (6, 10); 2) Cleaning of the piping system (6, 10) to remove the impurities; 3) Checking the cleanliness of the piping system (6, 10), Mobilization is carried out by means of evacuation, application of heat, application of electromagnetic radiation, induction, application of vibration or combinations of the aforementioned measures.

2. Method according to claim 1, wherein the cleaning is carried out by means of pressure flushing, pressure alternating flushing, evacuation, pulse evacuation or combinations of the aforementioned measures.

3. Method according to claim 1 or 2, wherein the purity check is carried out by means of sorbent tube analysis, residual gas analysis, real time VOC analysis, TOC analysis or combinations of the aforementioned methods.

4. Method according to one of the preceding claims, wherein during evacuation a pressure < 10 3 mbar, preferably < 10 3 mbar, especially preferably < 10' 5 mbar is reached.

5. A method according to any of the preceding claims, wherein the evacuation is carried out by means of one or more vacuum pumps (12), wherein the vacuum pumps (12) comprise rotary vane pumps, diaphragm pumps, screw pumps, ion getter pumps, titanium sublimation pumps, turbomolecular pumps, scroll pumps, piston pumps, diffusion pumps, cryopumps or combinations thereof.

6. Method according to one of the preceding claims, wherein a temperature > 30 °C, preferably > 60 °C, particularly preferably > 90 °C is reached during the application of heat.

7. Method according to any of the preceding claims, wherein the application of heat is carried out by means of one or more heating devices, the heating devices comprising fan heaters, heating blankets, heating tents, heating tapes, heating chambers, ovens and combinations thereof.

8. Method according to one of the preceding claims, wherein, in the course of applying vibration, a frequency between 1 Hz and 100 kHz, preferably between 30 Hz and 80 kHz, particularly preferably between 60 Hz and 40 kHz, is achieved.

9. Method according to one of the preceding claims, wherein the application of vibration is carried out by means of an ultrasonic bath, a mechanical vibration platform or a combination of the aforementioned.

10. Method according to any of the preceding claims, wherein the pressure purging or pressure cycling purging is carried out with an inert and / or reactive purging gas.

11. Method according to any of the preceding claims, wherein the purge gas is selected from the group comprising XCDA, nitrogen, noble gases, carbon dioxide, oxygen, ozone, hydrogen peroxide, chlorine, hydrogen and combinations of the aforementioned.

12. Method according to any of the preceding claims, wherein the purge gas is a reactive plasma.

13. Method according to one of the preceding claims, wherein a flow rate > 1 sccm, preferably > 10 sccm, particularly preferably > 30 sccm or > 50 sccm is achieved during pressure flushing or pressure alternating flushing.

14. Method according to one of the preceding claims, wherein the evacuation and / or pressure flushing is carried out bidirectionally from two different sides of the piping system (6, 10).

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