A washing system for in-line measurement systems for mineral slurries

Abstract

The invention relates to a comprehensive and automated washing system and methodology, designed as a complementary system to optimise the availability of in-line measurement systems for mineral slurries; in particular, but not exclusively, capillary rheometers, which typically become blocked due to the presence of material and / or the settling of particles in areas of restricted flow, causing measurement errors or system stoppages. The washing system primarily comprises an arrangement of hydraulic connections that ensure efficient cleaning in critical areas, such as instrumentation lines, and allow washing in both the direction of the mineral slurry flow and in the opposite direction; a washing control logic that ensures the sequential cleaning of in-line measurement equipment components, optimising washing times and increasing the availability of in-line measurement systems.

Description

[0001] DESCRIPTIVE MEMORANDUM

[0002] STATE OF THE ART

[0003] The transport of minerals during processing stages is a crucial component of the mining industry. This process begins with the formation of a mineral slurry, composed of solid particles resulting from the grinding of the extracted material. By reducing the size of the mineral, a finer material is obtained which, when mixed with water, constitutes the mineral slurry. This mineral slurry behaves as a continuous medium, which can be conveyed similarly to any other fluid through, for example, pipes or channels.However, the properties of mineral pulp can vary depending on the percentage of solids, particle size distribution, particle geometry, and ionic interactions of the colloidal system [1]. In addition, the mineralogy of the material, including its composition, density, and surface properties, and the presence of colloidal materials such as clay, can alter the tertiary properties of the mineral pulp. In principle, mineral pulps behave as a non-Newtonian fluid [2], which implies an initial effort to initiate their movement, known as yield stress. Furthermore, their viscosity varies depending on both temperature and shear rate, and therefore, on the flow conditions.In fact, the morphological properties of pulps can influence the energy efficiency of grinding [3]. Likewise, morphological properties can affect flotation [4], the optimal use of flocculant reagents in the thickening stage, and the mechanical conditions of pulp transport [5]. In thickening, for example, the morphology of the material can influence the efficiency of sedimentation rate, compression, and dewatering processes. An increase in viscosity directly affects the sedimentation rate and, therefore, increases the residence time of the particles. An increase in yield strength can increase the torque required to keep the mineral pulp moving, leading to a higher power demand and even thickener blockage.

[0004] In this context, understanding and controlling the Theology of mineral pulp becomes extremely relevant to optimize the transport of mineral pulps, and the sustainability of unit operations in the production process of mineralogical materials.

[0005] Although the importance of suspension properties in mineral processing is recognized, they are often not monitored in processing plants or incorporated into process design and optimization [3]. This is because the suspension properties are complex, given their inherent instability. Generally, the suspension properties are characterized by batch measurements in laboratories using Brookfield-type rotary viscometers [4], based on samples obtained from the field.However, since the thiological properties of mineral pulps depend on the deformation history (thixotropy or rheopexy), this type of measurement frequently leads to results that are not representative of what happens in the process, generating information of low reliability, in conjunction with problems associated with particle sedimentation [4], [6]. For example, an operating hydrocyclone can reach a shear rate of 508 s'. 1 , whereas measurements in a laboratory viscometer operate at values ​​below 74 s -1 [6] This is highly relevant for non-Newtonian fluids, such as mineral pulp, where viscosity depends strongly on shear rate [7], and therefore, the data obtained by this methodology do not apply to the operating conditions of the cyclone.

[0006] In this context, online rheological measurement systems have been incorporated, aiming to overcome these differences and provide reliable results. Among them is the patent granted to Rheology Solution Pty Ltd. [8], currently protected in Austria (ATE539341T1) and expired in the European Union and the United States. The device consists of a system for evaluating the properties of a fluid flowing through a pipe. Within the pipe is a test cell comprised of two parallel plates aligned with the flow direction. One plate is movable relative to the other, close enough to create a stagnant region between the surfaces. The measurement involves setting one surface in motion and measuring the movement of the counter-surface in response to the movement of the first.In this way, the fluid's velocity measurements can be obtained at a specific and predetermined time. Then, the surfaces separate to release the fluid, allowing for another measurement. Another velocity system is the patent granted to Aspect Imaging Ltd. [9] with international protection, which consists of a system for online measurement of the flow velocity, density, and velocity of a moving fluid, involving several subsystems. The invention mainly consists of a horizontal tube, in which a device for measuring velocity profile is located, and a vertical tube connected to the horizontal tube, with two pressure sensors at a predetermined vertical distance.The invention covers a wide range of velocity profile meters, including pressure sensors, nuclear magnetic resonance (NMR) spectroscopy, and direct wall tension sensors for determining shear stress, among others described in the prior art. One of the major disadvantages of these rheometers is the accumulation of sediment during their use, and since they lack cleaning systems, these devices must be removed from the pipeline, reducing their operational availability.

[0007] Another type of rheometer is based on the capillary measurement principle. These instruments estimate the atomic characteristics of a fluid from measurements of pressure, fluid flow rate, and the characteristics of the capillary tubes. Based on this principle is the patent granted to Politechnika Lodzka

[0010] , which consists of a capillary atomic system for non-Newtonian fluids, especially unstable atomic systems. The invention includes a temperature-controlled segment designed to disrupt the internal structure of the fluid, followed by a measuring device with at least two straight capillary systems of different dimensions equipped with flow meters and pressure sensors. A similar atomic measurement system is the patent granted to JRI Ingeniería SA.

[0011] , protected in Chile, consists of an in-line, U-shaped, multi-capillary telecommunications system that simultaneously measures the viscosity and yield strength of mineral suspensions at minute intervals, taking into account sedimentation effects, capillary wall effects, temporal effects, and capillary entry effects. The geometry of the measuring equipment and the nature of the in-line measurement require a flushing system to prevent the accumulation of particulate matter on the capillary walls. This system, described in the patent as a valve-driven flushing system, injects water to expel the fluid of interest using positive pressure and is not protected under this invention.Similarly, the patent granted to the University of Concepción

[0012] , protected in Chile, consists of an online rheometer that allows for the online determination of the properties of mineral suspensions. The invention's key feature is the capillary system composed of helical capillary tubes equipped with pressure sensors and ultrasonic Doppler flow meters. The system is advantageous because its helical geometry reduces the effects of mineral particle sedimentation.

[0008] In this regard, the only protected capillary tube cleaning system used in theological measurement systems is the internationally protected patent granted to Ticona LLC

[0013] . This patent consists of instrumentation for cleaning and packing the capillary tube in a capillary rheometer, using a linear motion device that controls a rod adapted for cleaning or packing the capillary tube. This system is only suitable for straight capillary tubes. Although numerous technologies have been developed for the online theological measurement of non-Newtonian fluids, such as mineral pulps, these systems still face significant problems with particulate matter accumulation in the rheometer's internal channels. This accumulation can be due to the particle size distribution, mineralogy, or sedimentation of the material.Therefore, it is necessary to implement a cleaning system that complements the measurement systems to increase the availability and efficiency of these devices.

[0009] Conventional flushing systems, which typically operate from an upstream point applying positive pressure, have significant limitations in their ability to remove debris from hard-to-reach areas. These areas can include instrument connection points, such as sensors, and constrictions, such as sections of reduced-diameter pipe. The accumulation of particles and sediment at these points can persist even after flushing procedures, compromising cleaning effectiveness and the functionality of online measuring equipment. This underscores the need to develop more effective and targeted flushing solutions capable of reaching and thoroughly cleaning these critical, hard-to-reach areas.

[0010] In this regard, the present invention proposes an integrated and automated washing system that complements online mineral pulp measurement systems. This system addresses and solves equipment availability problems caused by fouling and sediment buildup. BRIEF DESCRIPTION OF THE FIGURES

[0011] Figure 1 Illustration of the washing system (A) as a complementary unit to an online measuring equipment (B) of mineral pulps from a concentration process (C).

[0012] Figure 2 Representative diagram of the online washing system with its components, connections and programmable logic controller.

[0013] Figure 3 Washing methodology for an online measuring device that analyzes pulp samples from pipes.

[0014] Figure 4 Washing methodology for an online measuring device that analyzes pulp samples from gutters. REFERENCES

[0015] [1] N. Cruz, J. Forster, y E. R. Bobicki, “Slurry rheology in mineral processing unit operations: A critical review”, Can. J. Chem. Eng., vol. 97, n° 7, pp. 2102-2120, jul. 2019, doi: 10.1002 / cjce.23476.

[0016] [2] F. Concha A., “Suspension Rheology”, en Solid-Liquid Separation in the Mining Industry, F. Concha A., Ed., Cham: Springer International Publishing, 2014, pp.

[0017] 341-371. doi: 10.1007 / 978-3-319-02484-4_10.

[0018] [3] F. N. Shi y T. J. Napier-Munn, “Measuring the rheology of slurries using an online viscometer”, Int J Min. Process, 1996.

[0019] [4] L. Wang y C. Li, “A Brief Review of Pulp and Froth Rheology in Mineral Flotation”, J. Chem., vol. 2020, pp. 1-16, feb. 2020, doi: 10.1155 / 2020 / 3894542.

[0020] [5] Q. D. Nguyen y D. V. Boger, “Application of rheology to solving tailings disposal problems”, Int. J. Miner. Process., vol. 54, n° 3-4, pp. 217-233, ago. 1998, doi: 10.1016 / S0301 -7516(98)00011 -8.

[0021] [6] S. K. Kawatra y A. K. Bakshi, “On-line measurement of viscosity and determination of flow types for mineral suspensions”.

[0022] [7] R. W. Fox, A. T. McDonald, y J. W. Mitchell, “Fundamental Concepts”, en Fox and McDonald’s Introduction to Fluid Mechanics, 10 a ed., John Wiley & Sons, 2020, pp. 15-37.

[0023] [8] V. T. O’Brien, “Fluid properties evaluation”, US7054766B2, 30 de mayo de 2006 Accedido: 11 de julio de 2024. [En línea]. Disponible en: https: / / patents.google.com / patent / US7054766B2 / en

[0024] [9] EJ TOZZI and U. Rapoport, “Inline rheology / viscosity, density, and flow rate measurement”, US9494503B2, November 15, 2016. Accessed: July 12, 2024. [Online]. Available at: https: / / patents.google.com / patent / US9494503B2 / en?assignee=jr

[0025]

[0010] P. Domagalski, H. Fidos, and M. Karczewski, “Capillary rheometer”, PL234174B1, January 31, 2020. Accessed: July 22, 2024. [Online]. Available at: https: / / patents.google.com / patent / PL234174B1 / en

[0026]

[0011] MA Fuenzalida Orellana, A. Alvarez Vallejos, JC Rayo Prieto, and JD Rayo Calderón, “Rheometer system for measuring viscosity and yield stress, associated method.”, CL202100231, December 21, 2022

[0027]

[0012] L. Gutiérrez, F. Parada, J. Ortega, and G. Lotero, “A helical flow rheometer to determine online the tertiary properties of mineral suspensions with solid contents between 20 - 70%.”, CL201701274, December 1, 2017

[0028]

[0013] RC Phillips and BW Old, “Capillary rheometer with instrumented cleaning and packing device”, W02008049051A1, April 24, 2008. Accessed: July 22, 2024. [Online]. Available at: https: / / patents.google.com / patent / W02008049051A1 / en DESCRIPTION OF THE INVENTION

[0029] The present invention contemplates an integral and automated washing system (A) that acts as a component cleaning system for an online measuring equipment (B) of mineral pulps (C), specifically, but not exclusively, for capillary rheometers.

[0030] This system solves the problem of low online sensor availability caused by the accumulation of particulate matter that can settle inside components during measurements. This problem occurs mainly in restricted passage areas or smaller diameter orifices, such as those of pressure transmitters. This issue is exacerbated during unscheduled shutdowns or due to abrupt changes in the measurement systems.

[0031] The novel and key properties of the flushing system lie in: (1) the flushing control logic and (2) the arrangement of the hydraulic connections, which ensures the entry of water in turbulent flow into restricted areas. The first guarantees sequential cleaning of the components of the online measuring equipment, while the second ensures that, with a water supply at an appropriate pressure, preferably between 3 and 10 bar, and turbulent flow, preferably with a Reynolds number between 10,000 and 35,000, the removal of settled particles in restricted pipes or restricted passage areas can be achieved. This ensures effective cleaning of hard-to-reach sections of the online measuring equipment, especially in restricted areas such as the pressure transmitters used for the instrumentation shown in the figure.

[0032] The Error! Reference source not found diagram shows the equipment, which consists of the following components:

[0033] a) A multi-point water supply manifold (a);

[0034] b) Two reductions (b)

[0035] c) Electrically operated valves (c);

[0036] d) Hydraulic hose connectors (d);

[0037] e) Hoses (e); f) A programmable logic controller or PLC (f);

[0038] g) An HMI interface (g);

[0039] h) Check valves, (h);

[0040] The manifold has the following specifications:

[0041] • The manufacturing material can be steel regardless of the technical specification, except in saline environments where a material resistant to corrosion caused by the presence of chloride should be used, preferably, but not exclusively, stainless steel.

[0042] • The dimensions of the manifold must comply with a maximum length of 2 meters, and a maximum diameter of 15 cm.

[0043] • Water enters by opening valve c.1, while the pressure regulation of the washing system is carried out by controlling the opening of valve c.2, which are installed, as indicated in the Error! Reference source not found., on the longest shaft of the manifold.

[0044] • The number of connections available for washing, arranged on the shorter axis of the manifold, is preferably between 3 and 12, and more preferably around 8, of which 2 are always enabled in order to guarantee the injection of water to 2 points of the capillary, while the remaining 6 can be enabled to guarantee the cleaning of other components of the equipment, if required, and can be distributed as follows: 2 for a possible standby capillary, 1 for the rheometer pulp pumping system, 1 for cleaning the storage tank and 2 for cleaning the sampling system conduit.

[0045] • The manifold has no restrictions regarding the way it should be installed, and can be horizontal, vertical, or diagonal.

[0046] To ensure the turbulence, pressure, and flow conditions of the washing fluid, the following specifications must be respected: • The reductions (b) must comply with the major external diameter / minor external diameter ratio of between 2:1 and 6:1, and more preferably 3:1. In addition, the major external diameter must be equal to the outside diameter of the Manifold.

[0047] • Both the electrical conditioning valves (c.3) and the check valves (h) should preferably comply with the valve diameter / manifold diameter ratio of 1:3.

[0048] • The connectors (d) should preferably comply with the connector diameter / manifold diameter ratio of 1:3.

[0049] • Hoses, connectors, and valves must have the same diameter.

[0050] One of the key features of the washing system lies in its washing logic, as the PLC (f) allows for the programming of cleaning cycles that alternate with measurements from the online measuring equipment. Furthermore, the system enables manual cleaning by adjusting parameters via the HMI interface (g), thus providing greater flexibility and control during operation.

[0051] For a complete cleaning of the online measuring equipment, some components of it may be linked to the PLC, such as booster pumps or purge valves.

[0052] The washing system, with its centralized control via PLC (f) and HMI interface (g), offers complete automation, optimizing the management of the wash water flow supplied to the system through adjustable pipes or hoses operating at pressures between 3 and 10 bar. The washing logic begins with the opening of an electrically actuated valve (c.1), configured to allow water to enter the manifold (a) through a concentric reducer (b). Wash system pressure regulation is achieved by opening a valve (c.2). Once the system pressure is controlled, the opening of one of the electrically actuated valves (c.3) is controlled. These valves are connected to the hoses via hydraulic connectors (d) and have check valves (h) at the end of the connection, preventing backflow or pulp from entering the washing system.Through these hoses, water is injected to the desired washing point, depending on the washing logic used, which is detailed below and in the application examples. The water used for cleaning is removed from the online metering equipment through its pulp discharge line or via purge lines, if present. The reference sources [Error! Reference source not found] and [Error! Reference source not found] detail the preferred washing sequences for some online metering equipment used in concentrator plants.In both cases, the washing process begins after the online measuring equipment is stopped. If the equipment has a conditioning tank, the first step is to discharge the pulp from the tank using the booster pump. The pulp is then discharged through the process line or the purge valve, via its electrical actuation, followed by washing the tank. Ideally, the auxiliary instrumentation in the tank can also be washed. The tank is then emptied and refilled to remove any sediment or remaining solids from the bottom, which can be repeated if necessary.

[0053] The previous step can be performed sequentially or simultaneously with a backwash, which is defined as the introduction of water in the opposite direction of the pulp flow to the online measuring equipment. This is done to remove sediments or obstructions that may occur in the sampling line. The next step consists of opening the water injection valves (c.3) connected to the capillaries to inject water under positive pressure. Once this step is completed, these valves are closed, and then the water injection valves for washing the pressure transmitters are opened, as shown in the [Error! Reference source not found...]. ADVANTAGEOUSLY, the washing water enters through the pressure transmitters, thus allowing the removal of particles settled in restricted areas of the pipes.Furthermore, when possible, the wash water discharge can be directed towards the sensors or auxiliary instrumentation to improve the effectiveness of particle removal in these areas. This allows wash cycles to last approximately 15 minutes, which can be extended up to 1 hour for repeated washing of the storage tanks. In this way, the washing system increases the availability of the online measurement equipment.

[0054] These features and methodology of the washing system allow the online measuring equipment to adapt to different pulp conditions, ensuring equipment maintenance regardless of variations in operating conditions. Furthermore, the logical sequence enables a fast and precise washing process to maintain operational continuity. APPLICATION EXAMPLES

[0055] The washing system is a dynamic, complementary piece of equipment that can be adapted to different conditions and online mineral pulp measuring equipment. Two application cases for online rheometers are detailed below.

[0056] Case 1: For rheometers analyzing tailings slurries from pipes. The washing system has been implemented in the mining industry for cleaning components of online rheometers, which analyze tailings slurry at the thickener outlet. These rheometers include various sections that require periodic cleaning, such as sampling pipes, conditioning tanks, capillaries, and discharge pipes. A washing sequence was established, as detailed in the [Error! Reference source not found]. It is crucial to note that the characteristics of the slurry and the monitoring conditions of the equipment can lead to changes in cleaning times. For this reason, the proposed invention allows adjusting the execution times for each step of the washing sequence, thus ensuring the complete removal of particulate matter accumulated in the rheometers.Some tailings pulp conditions and washing times are cited.

[0057] Table 1 Solids content and yield stress of mining tailings pulps, and times associated with washing with the proposed washing system.

[0058]

[0059] a Cp : Solids content by weight of the pulp (wt. %), b T0 : Yield stress of the analyzed pulp. Case 2: For rheometers that analyze slurry tailings from channels

[0060] The need to analyze the tertiary characteristics of mineral slurries has led to the installation of online rheometers that analyze samples from sluice boxes. Unlike rheometers connected to mineral slurry pipelines, these devices must contend with the potential presence of foreign material that could obstruct a section of the rheometer, as well as the requirement of a sampling pipe that must always be primed. To address this, the proposed washing system allows for the configuration of a specific washing sequence, detailed in the [Error! Reference source not found.], to handle the particularities of slurries from sluice boxes. The execution times for each step of the sequence can be adjusted to suit specific cleaning needs, thus ensuring the complete removal of remaining solids and optimizing rheometer performance.This adaptability ensures that the rheometers operate efficiently and provide high-quality data for decision-making in mineral processing.

[0061] Table 2 Solids content and yield stress of mining tailings pulps, and times associated with washing with the proposed system.

[0062]

[0063] a Cp : Solids content by weight of the pulp (wt. %), b T0 : Yield stress of the analyzed pulp.

[0064] The application examples shown above are illustrative, serving to demonstrate the advantages of the invention. In this context, the appended claims are intended to claim the invention as broadly as possible, as conceived, and the examples presented are illustrative of applications selected from a range of all possible embodiments.

Claims

CLAIMS In the broadest possible sense, the invention protects:

1. An integrated and automated washing system, designed as a complement to online mineral pulp measurement systems, CHARACTERIZED by including: a) A manifold (a) with multiple connection ports for water inlet and outlet; b) two reducers (b) connected to the manifold, intended for the inlet and outlet of water; c) electrically operated valves (c), coupled to the manifold, arranged to control the water distribution and the corresponding washing cycles according to control logic; d) hydraulic hose connectors (d) connecting the valves to the manifold; e) hydraulic connection lines (e) to distribute water to key points of the online metering equipment; f) a programmable logic controller (PLC) (f), for programming and controlling the washing cycles in an automated manner or by remote control; g) an HMI interface (g) to allow manual operation and monitoring of the washing system; h) check valves (h) connected to the opposite end of the hydraulic lines (e) to prevent pulp from entering the measuring equipment components into the manifold; where the programmable logic controller (PLC) is configured to carry out washing cycles, by means of the selective and sequential activation and deactivation of the different electrically driven valves (c), to control different washing flows to the different components of the measuring equipment.

2. An integrated and automated washing system according to claim 1, CHARACTERIZED in that the manifold (a) can be made of steel regardless of the technical specification or another metal or alloy that is compatible with the use of water; however, in saline media, the manifold must be constructed of a corrosion-resistant material, preferably, although not exclusively, stainless steel or titanium.

3. An integrated and automated washing system according to claim 1, CHARACTERIZED in that the manifold can be installed horizontally, vertically or diagonally.

4. An integrated and automated washing system according to claim 1, CHARACTERIZED in that the reductions (b) are based on the ratio of larger external diameter to smaller external diameter with values ​​in the range of 2:1 to 6:1, and more preferably 3:

1. In addition, the larger external diameter must be equal to the external diameter of the manifold.

5. An integrated and automated washing system according to claim 1, CHARACTERIZED in that the dimensions of the manifold correspond to a maximum length of 2 meters, and a maximum diameter of 15 cm.

6. An integrated and automated washing system according to claim 1, CHARACTERIZED in that the number of connections to the manifold is a minimum of 3 and a maximum of 12, which are arranged to enable the cleaning of the components of the online measuring equipment.

7. An integrated and automated washing system according to claim 1, CHARACTERIZED in that the hydraulic lines, connectors and valves have the same diameter in order to maintain water pressure, and in turn preferably obey a diameter ratio of around 1:3 with respect to the manifold.

8. An integrated and automated washing system according to claim 7, CHARACTERIZED in that at least one of the valves and hydraulic lines has a diameter smaller than that specified in the ratio 1:3.

9. An integrated and automated washing system according to claim 1, CHARACTERIZED in that the water discharge at the cleaning points of the online measuring equipment generates turbulence, with a Reynolds number that is preferably between 10000 and 35000.

10. A method for performing the cleaning of online measuring equipment using the integrated and automated cleaning system according to claim 1, CHARACTERIZED in that it comprises the step of having a washing system that includes: a manifold with multiple connection ports for water inlet and outlet; a plurality of electrically actuated valves, coupled to the manifold and configured to allow water distribution; and a programmable logic controller (PLC) configured to selectively and sequentially activate and deactivate the various electrically actuated valves, and also to control components of the online measuring equipment; all of this allowing the following steps to be carried out: a) Discharge of the pulp contained in a conditioning tank, if one exists, which can be done by using a booster pump present in the online measuring equipment. b) Injection of wash water for cleaning the sampling line of the online measuring equipment, which can be done in the opposite direction to the entry of the pulp into the online measuring equipment; c) Injection of wash water for cleaning process lines of the online measuring equipment, which can be done in the same direction as the pulp flows into the online measuring equipment; d) Injection of washing water for cleaning the instrumentation lines and restricted passage areas, such as pressure transmitters, this is done by allowing the water to flow in the same direction as it flows from the pulp into the online measuring equipment.

11. A method for performing the cleaning of the online measuring equipment according to claim 10, CHARACTERIZED in that the injection of cleaning water for washing the sampling lines, process lines and instrumentation lines is carried out at a pressure that varies between 3 and 10 bar.

12. A method for performing online cleaning of measuring equipment according to claim 10, CHARACTERIZED in that steps a) and b) can be performed sequentially or in parallel.

13. A method for performing online measuring equipment cleaning according to claim 10, CHARACTERIZED in that the cleaning of the storage or conditioning tanks includes cleaning water injection lines directed to the instrumentation sensors.

14. A method for performing the cleaning of the online measuring equipment according to claim 10, CHARACTERIZED in that the cleaning of the tanks includes a partial filling and repeated emptying of the tanks present.

15. A method for performing the cleaning of the online measuring equipment, according to claim 10, CHARACTERIZED in that the discharge of the material present in the tank can be carried out through the process lines of the measuring equipment, or through a purge line, if the latter is available, by activating the corresponding electric drive to ensure its operation.

16. A method for performing the cleaning of the online measuring equipment according to claim 10, CHARACTERIZED by the arrangement of the hydraulic connections, where the entry of washing water can be carried out through the cleaning channels of the pressure transmitters, thus allowing the removal of particles settled in these restricted areas.

17. A method for performing the cleaning of the online measuring equipment according to claim 10, CHARACTERIZED by a control logic that allows the washing sequence to be adjusted automatically with a duration equal to or less than 15 minutes.

18. A method for performing the cleaning of the online measuring equipment according to claim 17, CHARACTERIZED in that the washing time can be extended up to 1 hour in case of cleaning of the storage tanks, which can happen repeatedly.

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