HIGH-PRESSURE SYSTEM, METHOD FOR DETERMINING A FLOW CONTROL VALUE OF A FLUID FLOWING THROUGH A HIGH-PRESSURE SIDE HIGH-PRESSURE PUMP OUTLET OF A HIGH-PRESSURE PUMP, AND USE OF AN ULTRASONIC MEASURING DEVICE FOR DETERMINING A FLOW RATE THROUGH A THICK-WALLED PIPE OF A FLUID FLOWING THROUGH A HIGH-PRESSURE SIDE HIGH-PRESSURE PUMP OUTLET OF A HIGH-PRESSURE PUMP

Description

[0001] The present invention relates to a method and a high-pressure system for determining a flow control parameter of a fluid flow passing through a high-pressure-side outlet of a high-pressure pump, in particular a fluid flow passing through a high-pressure piping system (high-pressure pipe) connected to the high-pressure-side outlet of a high-pressure pump. The invention further relates to the use of an ultrasonic measuring device for determining a flow control parameter of a fluid flow passing through a thick-walled pipe of a high-pressure-side outlet of a high-pressure pump. STATE OF THE ART

[0002] Plants, such as chemical plants, exhibit a complex interplay of material and energy flows, which must be continuously monitored, particularly to ensure product quality, operational safety, and trouble-free plant operation. It is well known that the measuring devices in high-pressure systems, in particular, are subject to stringent requirements due to the prevailing operating conditions. The frequently used organic and inorganic, toxic, and corrosive media, which must be monitored with regard to temperature, pressure, and / or flow rate, can lead to wear and tear on the measuring instruments and consequently to measurement inaccuracies.Conventionally used instruments, such as orifice plates and other differential pressure gauges, magnetic-inductive flow meters, vortex flow meters, and Coriolis flow meters, require frequent maintenance, which leads to production downtime. Furthermore, they cause pressure loss in the pipeline. Both of these factors reduce plant availability and profitability.

[0003] Particularly in high-pressure systems, such as those used for the polymerization of ethylene (ethene) or propylene (propene), the difficulty of obtaining accurate and meaningful measurement results repeatedly arises. This is due, firstly, to the fact that, especially in high-pressure polymerization systems or in the production of ethylene copolymers, the substances being measured themselves pose a challenge, as their flow rate (volume flow or mass flow) is very low, amounting to only a few liters per hour. Furthermore, high-pressure systems also cause a change in substance density due to the prevailing high pressure, which significantly alters the propagation speed of sound within the medium. The fluids to be monitored in these high-pressure systems are known to be pumped in so-called high-pressure pumps (e.g.,...).In high-pressure intensifiers, phased-flow pumps, and hand-operated pumps, the fluid is compressed to the required pressure, resulting in pressure pulsation. This pulsating signal of the pumped medium (fluid) leads to undesirable inaccuracies in the measurement result. Furthermore, these pressure changes also cause changes in the geometry of the high-pressure lines of the high-pressure system. In particular, the high-pressure pipes used, which have a small inner diameter and a correspondingly large wall thickness, significantly complicate the measurement of the flow rate, for example, of initiators (peroxides) and comonomers. Additionally, the propagation speed of sound also depends on the stress states in the pipe material; that is, it changes with increasing pressure.

[0004] It is generally known to use non-invasive measuring devices, such as a clamp-on ultrasonic measuring device, particularly in low-pressure systems, to enable measurement using a low-maintenance and low-wear measuring instrument, as mentioned above. The clamp-on ultrasonic measuring device is attached externally to a part of the system, such as a section of pipe in a piping system, and measures the velocity of flowing liquids or gases (fluids) using the well-known ultrasonic transit-time difference method. The ultrasonic transit-time difference method is a technical procedure used to determine transit-time differences between ultrasonic waves traveling in opposite directions through a fluid. These transit-time differences arise due to the deflection of the mechanically coupled ultrasonic waves caused by the movement of the fluid.Consequently, the runtime differences serve as the basis for determining the fluid velocity, which in turn enables a statement about the volume flow and mass flow (Source: Flexim GmbH).

[0005] These ultrasonic measurement systems are currently used in operating high-pressure plants only to measure the initiator or comonomer being introduced into the reactor on the low-pressure side, particularly the suction side of the high-pressure pump, especially in high-pressure polymerization plants or in the production of ethylene copolymers. Often, only the stroke rate of the high-pressure pump is monitored to obtain a measurement. However, this measurement can only vaguely or approximately indicate the true volumetric flow rate of the fluid flowing into the reactor. Furthermore, often only the end product itself is tested to determine whether the amount of fluid (initiator or comonomer) dosed into the reactor was optimal. If an undesired deviation from the target state is detected, in the worst case, the entire product batch must be destroyed, which in turn is associated with high production costs.

[0006] In the case of applications such as waterjet cutting systems or high-pressure pastorizing systems, where high-pressure pumps are used that can generate a water pressure of up to 6000 bar, the flowing fluid is measured in a known manner by measuring the high-pressure side of the high-pressure pumps with the turbine flow meters permanently installed in the high-pressure lines, but only up to 4000 bar.

[0007] Numerous applications of ultrasonic measuring devices are known, particularly in low-pressure systems, as are modifications of ultrasonic measuring devices, as listed below. German patent DE 10 2017 002 297 A1 describes a centrifugal pump unit with a flow sensor. The electrically driven centrifugal pump unit comprises a pump housing and a flow sensor for providing a flow rate value, which is mounted in or on the pump housing, and is connected to pump electronics for controlling the centrifugal pump unit depending on the flow rate value. WO 2018 / 072926 A1 describes the use of a clamp-on ultrasonic sensor for an ultrasonic flow meter. The clamp-on ultrasonic sensor is designed to generate at least one Lamb wave mode in a measuring tube wall of the ultrasonic flow meter.To ensure compatibility with various types of measuring tubes, the clamp-on ultrasonic sensor features an interchangeable coupling element adapted to each specific tube type. US Patent 7,624651B2 describes a device for attenuating an unwanted component of an ultrasonic signal. The device comprises a sensor attached to a tube, including a transmitter and a receiver. The transmitted ultrasonic signal contains a structural component that propagates through the tube and a fluid component that propagates through a flow within the tube. The device includes an attenuating structure that attenuates the structural component of the ultrasonic signal and consists of a housing attached to the tube to modify the ultrasonic vibration characteristics.

[0008] CN100578191C describes a measurement of a rheological property of a high polymer system, wherein a tester is used to examine the rheological properties of supercritical fluids and ultrasonic irradiation on high polymer systems and the influence of these properties on the molded product. CN101074885B describes a transmit / receive flow meter that uses the changes in the state of a fluid to measure the propagation time. DE 10 2005 032636 A1 discloses a method for assessing the functionality of a high-pressure fuel supply system of a motor vehicle based on a fuel flow detected in the fuel supply system by means of ultrasonic flow measurement. REVELATION OF THE INVENTION

[0009] It is therefore the object of the present invention to at least partially overcome the disadvantages described above in measuring the flow velocity of a flowing fluid in a high-pressure system. In particular, it is the object of the present invention to provide a method and a high-pressure system for determining a flow control variable that, in a simple and cost-effective manner, enables both an accurate measurement of the volumetric flow rate (and / or mass flow rate) of the measured fluid, independent of the aforementioned difficulties in the measurement method for measuring fluid flow in high-pressure systems, and the determination of a value for a flow control variable for regulating the flowing fluid flow.

[0010] The foregoing problem is solved by a method for determining a flow control variable of a fluid flow passing through a high-pressure-side high-pressure pump outlet of a high-pressure pump, having the features of claim 9, and by a high-pressure system having the features of claim 1.

[0011] Furthermore, the aforementioned problem is solved by using an ultrasonic measuring device to determine a flow control variable of a fluid flow passing through a thick-walled pipe of a high-pressure-side outlet of a high-pressure pump, with the features of claim 15. Further features and details of the invention will become apparent from the dependent claims, the description, and the drawings. Features and details described in connection with the method according to the invention naturally also apply in connection with the high-pressure system according to the invention, in particular in connection with the use of the ultrasonic measuring device, and vice versa, so that the disclosure regarding the individual aspects of the invention always refers, or can refer, to each other. In addition, the method according to the invention can be carried out with the high-pressure system according to the invention.

[0012] According to a first aspect of the invention, the inventive method serves to determine a flow control variable of a fluid flow flowing through a high-pressure-side high-pressure pump outlet of a high-pressure pump of a high-pressure system according to the second aspect of the invention described below, comprising at least the following steps: Measurement of the flow velocity of the fluid flow through a pipe (high-pressure pipe, high-pressure piping) of the high-pressure-side high-pressure pump outlet by means of at least one ultrasonic measuring device, in particular an externally arranged ultrasonic measuring device, to obtain a measurement result of the flow velocity, transmission of the measurement result of the flow velocity to an evaluation unit, and calculation of a current flow value as well as the flow control variable from the measurement result of the flow velocity by means of the evaluation unit.

[0013] The ultrasonic measuring device used could, for example, be a clamp-on ultrasonic measuring device. This type of ultrasonic measuring device, which operates using an ultrasonic transit-time difference method, offers the advantage of simple, quick, and non-invasive mounting, as it is mounted externally on the high-pressure pump outlet. It is also conceivable that a hybrid measurement method, consisting of the transit-time difference method and a noise trek method, could be applied using the same ultrasonic measuring device. Consequently, as a hybrid device, the ultrasonic measuring device is also capable of emitting corresponding noise trek signals. In this case, stable measurement can be reliably performed even with a high gas and solids content in the fluid flow. The use of this device does not require any structural modification of the existing high-pressure system.The installation of the ultrasonic measuring device is not strictly necessary. It would be advantageous, however, to design at least an inlet section before the measuring section and / or an outlet section after the measuring section in such a way that the measured fluid flow is homogenized. The measuring section is advantageously defined as the section of pipe, particularly the high-pressure pipe at the high-pressure-side outlet of the high-pressure pump, where the at least one ultrasonic measuring device is located. It is also conceivable that at least two or more ultrasonic measuring devices, in particular a multitude of ultrasonic measuring devices, are arranged in the area of ​​the measuring section and aligned with each other in a metrologically optimized manner. The process taking place in the high-pressure system, such as polymerization, is not affected by the installation or use of the ultrasonic measuring device.Furthermore, the ultrasonic measuring device used offers virtually wear-free operation, as it does not come into contact with the fluids being measured and monitored, some of which may be toxic. The use of an ultrasonic measuring device also minimizes, and in some cases even completely eliminates, the risk of leakage. This is particularly important in high-pressure systems in potentially explosive atmospheres, where the entire measuring device must meet explosion protection requirements. Another advantage is that no additional pressure loss occurs in the high-pressure piping system during operation of the ultrasonic measuring device.

[0014] It is also conceivable to enable a multi-path arrangement and / or a series arrangement of ultrasonic measuring devices, which advantageously further increases the measurement accuracy and minimizes the influence of an asymmetrical flow profile. More precisely, this means that, for example, two or more ultrasonic measuring devices (within the measuring section) are arranged sequentially in the direction of flow at the same circumferential position of the pipe (high-pressure pipe), particularly on the same side of the pipe. In this case, the signal emitted by a first ultrasonic measuring device can be reflected off an inner wall of the pipe and received by the other adjacent ultrasonic measuring device, and vice versa. This is referred to as a reflection mode, in which the number of sound paths is even or corresponds to an even number.The first sound path is therefore the path between the transmitting ultrasonic measuring device and the inner wall of the pipe, while the second sound path is the path between the inner wall of the pipe and the receiving ultrasonic measuring device. Alternatively or additionally, it is conceivable that for each ultrasonic measuring device, a second ultrasonic measuring device is positioned on the opposite side of the pipe (high-pressure pipe) to receive and transmit signals. This is a transmission mode in which the number of sound paths is odd. If one ultrasonic measuring device transmits a signal through the pipe to its essentially opposite ultrasonic measuring device, this is a single sound path. Increasing the number of sound paths also increases the accuracy of the measurement, but simultaneously increases the signal attenuation.

[0015] The flow control variable, which can also be referred to as the flow control value within the scope of the invention, represents a value "x". This value "x" defines the deviation between an actual value, more precisely the measured flow value, in particular the measured flow velocity, and the target value, more precisely the specified required flow value, in particular the required flow velocity, over time "t". Accordingly, "actual * x = target". More precisely, determining the value "x", i.e., the flow control variable, yields a value that compensates for the difference between the measured actual value and the required target value. The required target value, more precisely the defined or specified flow value, is advantageously a variable quantity that can be changed and adjusted according to the requirements and conditions of the high-pressure system.The target values ​​are defined, for example, by the operator of the high-pressure system. Advantageously, these target values ​​are stored in a memory unit of an evaluation unit and can be queried or retrieved for individual operating modes of the high-pressure system.

[0016] The method according to the invention serves to measure fluids used in the high-pressure application areas presented below.

[0017] One initial application is the polymerization of polyethylene in a high-pressure system. This process generates pressures in the range of 1000–3500 bar, at which initiators, such as peroxides, are introduced into the reactor. One objective is to continuously optimize the amount of initiator introduced into the process with regard to production volume and plant safety. In particular, an unintentionally excessive amount of initiator increases the risk of an unintended, sudden decomposition of the ethylene, which in turn leads to a strong exothermic reaction and consequently to the shutdown of the entire high-pressure system. This necessitates precise measurement of the initiator flow upstream of the reactor, i.e., immediately before the initiator is introduced.The present invention allows the metered initiator quantity, in particular the metered peroxide quantity, and correspondingly also the initiator losses, to be measured on the high-pressure side, i.e., at the high-pressure pump outlet of the high-pressure pump. Initiator losses occur, for example, due to leaks at worn high-pressure seals.

[0018] Another application is the production of ethylene copolymers. In this process, comonomers such as vinyl acetate, methyl acrylate, or butyl acrylate are metered into the reactor using high-pressure pumps. The injection of comonomers into the ethylene takes place before or directly in the reactor. Since ethylene copolymers are modern, high-quality plastic products, precise measurement of the comonomer flow before the reactor, as well as its manual, semi-automatic, or preferably fully automatic dynamic regulation, is of immense importance.

[0019] Another area of ​​application is waterjet cutting systems or high-pressure pastorizing (HPP) systems, which use high-pressure pumps capable of generating water pressures up to 6000 bar. For these high-pressure systems, non-invasive measurement of the water volume at pressures up to 6000 bar is highly relevant for acceptance and testing purposes, as well as for the advantageously automatic detection of water leaks or nozzle blockages during operation.

[0020] The flow velocity of the fluid used, determined or measured by the ultrasonic measuring device (which is understood as the mean flow velocity and can also be referred to as flow rate), is transmitted by the ultrasonic measuring device to an evaluation unit. This evaluation unit is used to calculate a current flow value, such as a volumetric flow rate (dV / dt or V). Advantageously, this volumetric flow rate can be converted into a mass flow rate (dm / dt or V) using the fluid density. ṁThe current flow rate (volume flow, mass flow) thus indicates the currently measured actual state to the operator of the high-pressure system. This means that when the evaluation unit queries the current flow rate at a measuring point, such as the high-pressure pump outlet on the high-pressure side, the operator receives the currently prevailing volume flow or mass flow. This value can change continuously, as the flow velocity measurement is also continuous, and in particular dynamic. To display at least the current flow rate and the flow control variable, the evaluation unit has a display element, such as a screen, a display panel, etc. The evaluation unit determines the flow control variable based on the current flow rate.The flow control variable is, in particular, a value required to achieve a desired flow rate. This means the flow control variable is a factor necessary to achieve a specific volumetric or mass flow rate, ultimately a specific flow velocity of the fluid introduced into the reactor to obtain the expected result. Accordingly, the flow control variable is a control parameter used to determine how much the flow velocity of the fluid flowing through the high-pressure pump outlet must be increased or decreased to ensure the current flow rate remains within predefined limits.The specified limit values ​​are set with regard to the desired end product and enable the introduction of a specified and required amount of fluid into the reactor.

[0021] According to one embodiment, the measurement of the flow velocity, the transmission of the measurement result, and the calculation of the current flow rate and the flow control variable are performed dynamically. This means that the ultrasonic measuring device continuously detects / measures the flow velocity and consequently transmits it continuously to the evaluation unit as a measurement result. This evaluation unit then continuously determines the current flow rate, in particular the current volumetric or mass flow rate, as well as a flow control variable, in particular a flow control value, from this measurement result. The subsequent control of the high-pressure pump is also dynamic.

[0022] According to another embodiment, the evaluation unit calculates the current flow rate using an equation method, that is, a mathematical calculation method using an equation or formula, and / or the flow control variable using a comparison method. For example, the current flow rate is calculated as the volumetric flow rate, which is the product of the pipe cross-section on which the ultrasonic measuring device is mounted and the measured flow velocity. The evaluation unit, particularly its processing unit, which is a component of the evaluation unit, advantageously calculates the current mass flow rate as the product of the previously calculated / determined volumetric flow rate and a fluid density.The obtained current flow rate, which can also be referred to as the actual flow rate (ACTUAL VALUE), is then advantageously compared to a target flow rate (TARGET VALUE), in particular a minimum target flow rate and a maximum target flow rate, using a comparison method. For this purpose, the evaluation unit includes, for example, a comparison unit, which is a component of the evaluation unit, specifically a component of the processing unit. If the actual flow rate is greater than or equal to the minimum target flow rate and less than or equal to the maximum target flow rate, no process control takes place, in particular no control of the high-pressure pump. However, if the actual flow rate is less than the minimum target flow rate or greater than the maximum target flow rate, process control is required. The evaluation unit determines the degree of deviation for this purpose, in particular the flow control variable.The flow control value is calculated from the actual flow rate to the minimum or maximum target flow rate, preferably via an equation. This is performed by the processing unit, in particular a deviation detection unit of the evaluation unit. The degree of deviation, especially the flow control variable or flow control value, indicates how much additional fluid must be introduced into the reactor or how much less fluid must be introduced. This flow control variable is therefore used to determine whether the flow rate of the high-pressure pump must be increased or decreased. The high-pressure pump is then controlled either manually (by an operator), semi-automatically, or advantageously (fully) automatically by actuators in order to regulate and control the high-pressure pump according to the result of the flow control variable.For this purpose, the evaluation unit is advantageously connected to at least one actuator on the high-pressure pump via a wired or wireless data transmission connection. The process of measuring, calculating, and controlling / regulating is a dynamic process that is therefore carried out continuously during the operation of the high-pressure system, so that the high-pressure pump can also be advantageously controlled continuously according to demand.

[0023] In a further embodiment, the flow velocity measured by the ultrasonic measuring device is corrected taking into account other available or determined information, such as the temperature and / or pressure of the fluid flow. The necessary mathematical relationships and, if applicable, required factors are determined theoretically or empirically. Additional sensors advantageously arranged along the measuring section, such as temperature and / or pressure sensors, can be useful in this regard. These sensors are also advantageously connected to the evaluation unit to transmit the determined data.

[0024] As a further aspect of the invention, a high-pressure system is claimed, which comprises a high-pressure pump with a high-pressure pump inlet and a high-pressure-side high-pressure pump outlet. At least one ultrasonic measuring device, in particular an externally arranged ultrasonic measuring device, is arranged at the high-pressure-side high-pressure pump outlet for measuring the flow velocity of a fluid flow passing through a pipe of the high-pressure-side high-pressure pump outlet. In particular, the at least one ultrasonic measuring device is arranged externally on the pipe (high-pressure pipe) of the high-pressure-side high-pressure pump outlet. It is particularly advantageous if the at least one ultrasonic measuring device is arranged within a measuring section on the pipe (high-pressure pipe) of the high-pressure-side high-pressure pump outlet. The pipe (high-pressure pipe) can be a component of the high-pressure-side high-pressure pump outlet or connected to it, in particular operatively connected.Advantageously, this makes it possible to determine the volumetric or mass flow rate of the fluid leaving the high-pressure pump and consequently entering the reactor, in order to control this, in particular the flow velocity of the fluid flowing through the high-pressure pump outlet. According to the invention, the high-pressure system is a high-pressure system, as described above, for the polymerization of ethylene and propylene or ethylene and comonomers, or a waterjet cutting system, or a high-pressure pasteurization system.

[0025] According to the invention, the high-pressure side outlet of the high-pressure pump has a thick-walled pipe with an inner diameter to outer diameter ratio of 1:1.5 to 1:5, with the ultrasonic measuring device being arranged on the outside of this thick-walled pipe. This thick-walled pipe is specifically designed for use in high-pressure systems and has a relatively small inner diameter compared to its relatively large outer diameter, resulting in a significantly thicker wall thickness than that of commercially available pipes in conventional systems. The inner and / or outer surface of this pipe can be machined with particular care to achieve a very fine surface finish and / or extremely tight geometric tolerances.

[0026] It is conceivable that the system includes a reactor chamber for carrying out a chemical, thermal, thermodynamic, or mechanical reaction, and that the thick-walled pipe is arranged directly or indirectly between the reactor chamber and the high-pressure pump. This means that the thick-walled pipe is connected to or attached to the high-pressure pump either directly (without any intervening element or component) or indirectly (via an intermediate element or component). The thick-walled pipe can be located at the high-pressure-side outlet of the high-pressure pump or be a component of the high-pressure-side outlet.

[0027] According to one embodiment of the invention, the high-pressure system is a system for the polymerization of monomers, in particular ethene (ethylene) and propene (propylene).

[0028] According to another embodiment, the thick-walled pipe comprises a material from the group of metal alloys, such as high-alloy or low-alloy steels, titanium alloys, copper alloys, nickel alloys, tantalum alloys, chromium alloys, or cobalt alloys. The thick-walled pipe is thus advantageously resistant to corrosive media and high-pressure resistant. Deformation of the thick-walled pipe is largely avoided, or advantageously prevented, due to the materials used. It is also conceivable that the thick-walled pipe comprises a mixture of the aforementioned metal alloys. Furthermore, the thick-walled pipe is not limited to these metal alloys.

[0029] It is also conceivable that the thick-walled pipe (high-pressure pipe) is fixed to the high-pressure pump by means of a flange. This flange has a flow channel with a section that increases conically at least partially in the direction of flow, extending over at least one-third, and in particular over half, of the total length of the flow channel. The geometry of the flange's flow channel described above advantageously allows for a smooth transition from the high-pressure pump outlet to the thick-walled pipe. This enables advantageously optimized flow conditions for the fluid coming from the high-pressure pump and flowing through the flange and the thick-walled pipe.

[0030] According to a further embodiment, the inner diameter of the thick-walled tube comprises a section that increases continuously at least in certain segments, a cylindrical section, and a section that decreases continuously at least in certain segments. Advantageously, all three sections are arranged sequentially such that, in the direction of flow, the section that increases continuously at least in certain segments is formed first, followed by the cylindrical section, and then the section that decreases continuously at least in certain segments. Advantageously, the sections merge into one another such that the first section merges into the next (second) section, and the next (second) section merges into the following (third) section. This advantageously homogenizes the flow conditions of the fluid flow so that a substantially uniform, mostly turbulent, fluid flow is generated.The advantage of this is that the measurement signal is more constant and has less noise overall.

[0031] According to a further embodiment, a straight, in particular curvature-free, calming section with a length at least five times the inner diameter (pipe inner diameter) of the thick-walled pipe is formed upstream of the ultrasonic measuring device, and a straight, in particular curvature-free, calming section with a length at least three times the inner diameter (pipe inner diameter) of the thick-walled pipe is formed downstream of the ultrasonic measuring device. The calming sections are advantageously pipe sections, in particular straight pipe sections or pipes. These pipes (calming pipes / calming pipe sections) are advantageously arranged upstream and downstream of the thick-walled pipe (high-pressure pipe) of the high-pressure-side high-pressure pump outlet and are connected / functionally connected to it.Alternatively, the calming sections can be segments of the thick-walled pipe (high-pressure pipe) of the high-pressure pump outlet on the high-pressure side. It is advantageous for the calming sections to be located before and after the measuring section, which is also a segment of the thick-walled pipe. The calming sections (as independent pipe segments or as sections of a common thick-walled high-pressure pipe) can each have a uniform inner diameter or an inner diameter that tapers or widens in the direction of flow. It is also conceivable that one calming section has a smaller / larger inner diameter than the other. The primary purpose of the calming sections is to homogenize the fluid flow and enable reliable and accurate measurement.

[0032] Furthermore, it is possible that the fluid stream consists of a fluid containing a chemical initiator, in particular peroxide, or a comonomer, in particular vinyl acetate, methyl acetate, or butyl acetate, or another liquid. This list is not exhaustive, however. Other fluids may also be part of the fluid stream.

[0033] The invention provides that the high-pressure pump is designed to generate a pressure between 1000 and 6000 bar. This advantageously enables a wide variety of applications in high-pressure systems.

[0034] According to another embodiment, the ultrasonic measuring device is connected to an evaluation unit via signal transmission or data transmission to transmit the measured fluid flow velocity to the evaluation unit. Data and signal transmission can be wireless or wired. The evaluation unit itself comprises a variety of additional units, such as a display unit for showing the determined / measured, calculated, and controlled / regulated data, and / or an input unit for entering or changing data and parameters.A calculation unit, a deviation detection unit, and / or a comparison unit are also conceivable units, whereby the calculation unit calculates the flow values ​​to be determined from the measurement results, the comparison unit compares the calculated values ​​with target values, and the deviation detection unit evaluates the result in relation to the target values ​​(determining deviations / degree of deviation / flow control variable). Transmitting and receiving units for data transmission are also helpful and are advantageously a component of the evaluation unit. Advantageously, the evaluation unit can be used for preferably (fully) automatic data acquisition and calculation, as well as (fully) automatic dynamic control of the high-pressure pump with regard to at least its flow velocity parameter.

[0035] Consequently, the high-pressure system advantageously incorporates control and regulating devices that serve to control or regulate the fluid's volumetric / mass flow rate as required. These control and regulating devices are advantageously arranged – viewed in the direction of flow – upstream of the ultrasonic measuring device, particularly upstream of the calming section.

[0036] The described high-pressure system offers all the advantages that have already been described for a method for determining a flow control variable according to the first aspect of the invention.

[0037] As a further aspect of the invention, the use of an ultrasonic measuring device for determining the (current / instantaneous) flow rate of a fluid flow passing through a thick-walled pipe of a high-pressure pump outlet on the high-pressure side of a high-pressure pump in a high-pressure system, as described above in the second aspect of the invention, is claimed. The ultrasonic measuring device is arranged externally on the thick-walled pipe of the high-pressure pump outlet, which has an inner diameter to outer diameter ratio of 1:1.5 to 1:5. This ultrasonic measuring device dynamically measures the (current) flow velocity of the fluid flow, and this measured flow velocity is then used as a measurement result at an evaluation unit to calculate a current flow rate and a flow control variable.A flow control value is transferred from the measurement result (also dynamically).

[0038] The described use yields all the advantages already described for a method for determining a flow control variable according to the first aspect of the invention and for the high-pressure system according to the second aspect of the invention.

[0039] An inventive use of an ultrasonic measuring device for determining the (current / instantaneous) flow rate of a fluid flow passing through a thick-walled pipe of a high-pressure-side outlet of a high-pressure pump, as well as an embodiment of an evaluation unit and a high-pressure system, are explained in more detail below with reference to the drawings. The drawings schematically show: Figure 1A in a perspective view of a section of a thick-walled pipe with ultrasonic measuring devices arranged in series, Figure 1B in a perspective view of a section of a thick-walled pipe with ultrasonic measuring devices arranged in parallel, Figure 2 in a schematic representation of an embodiment of an evaluation unit, Figure 3 in a sectional view of an embodiment of a thick-walled pipe with a flange for arrangement on a high-pressure-side high-pressure pump outlet, and Figure 4 a circuit diagram of an embodiment of a high-pressure system.

[0040] Elements with the same function and mode of operation are in the Figs. 1 to 4 each provided with the same reference numerals.

[0041] In the Figures 1A and 1B Each figure schematically shows a perspective view of a section of a thick-walled pipe 1 with ultrasonic measuring devices 10, 11 attached to it. In the Figure 1AIn the embodiment shown, the ultrasonic measuring devices 10, 11 are arranged in series. This means that both ultrasonic measuring devices 10, 11 are mounted on the same side of the pipe 1. This arrangement of the ultrasonic measuring devices 10, 11 is particularly suitable for the use of a reflex mode and for generating an even number of sound paths 2, 3. As shown in the Figure 1AAs shown schematically, two sound paths 2, 3 (dotted line) are generated: a first sound path 2 between the first ultrasonic measuring device 10 and the inner wall of the pipe 1, and a corresponding second sound path 3, connected to the first sound path 2, between the inner wall of the pipe 1 and the second ultrasonic measuring device 11. Since the second ultrasonic measuring device 11 also emits signals, in particular ultrasonic waves, it consequently also uses the two sound paths 2, 3, whereby the signals / sound waves consequently travel in the opposite direction to the first signals / sound waves. In the embodiment according to the Figure 1BThe ultrasonic measuring devices 10, 11 are essentially arranged in parallel. This means that the ultrasonic measuring devices 10, 11 are arranged on opposite sides of the pipe 1. Viewed in the direction of flow, the ultrasonic measuring devices 10, 11 are spaced apart from each other and are therefore not directly above one another. Rather, the ultrasonic measuring devices 10, 11 are spaced apart from each other in the direction of flow. This arrangement of the ultrasonic measuring devices 10, 11 is advantageously suited for the use of the transmission mode, in which an odd number of sound paths 2 are generated. As in the Figure 1BA sound path 2 is evident between the first ultrasonic measuring device 10 and the second ultrasonic measuring device 11. The sound waves emanating from the ultrasonic measuring devices 10 and 11 are therefore not reflected at the inner surface of the pipe 1, but penetrate the pipe 1 from one side to the other.

[0042] As in the Figures 1A and 1B As shown, the ultrasonic measuring devices 10, 11 are arranged externally on the thick-walled tube 1 and each is fixed by means of a fastening element 12, here, for example, designed as a fastening strap. The thick-walled tube 1 has an inner diameter Di and an outer diameter Da. Both ultrasonic measuring devices 10, 11 dynamically measure the flow velocity of the flowing fluid and continuously transmit the measurement results to an evaluation unit 50, as shown in the Figure 2 schematically represented.

[0043] The one in Figure 2The evaluation unit 50, shown schematically, advantageously comprises a plurality of units. The evaluation unit 50 receives, by means of the receiving unit 55, the measured values ​​(arrow 60) transmitted by the ultrasonic measuring devices 10, 11 with regard to the flow velocity or current velocity of the fluid passing through the thick-walled pipe 1 (see figure). Figure 1) flowing fluid. The received data / values ​​are then either passed on directly to a processing unit 51 (arrow 61) or indirectly to a storage unit 54 (arrow 62) and then, via this storage unit 54, which serves, among other things, for temporary data storage, to the processing unit 51 (arrow 63). The processing unit 51 determines a current flow value, such as a volumetric flow rate and / or a mass flow rate, from the currently transmitted data. This determined current flow value is then passed on to the comparison unit 52, which can be a component of the processing unit 51. The comparison unit 52 compares the received flow value with predefined minimum target flow values ​​and maximum target flow values. The result is then transferred to a deviation detection unit 53, which is also advantageously a component of the processing unit 51.The deviation detection unit 53 determines the manipulated variable, in particular the flow control variable, or the flow control value, required to control the high-pressure pump such that the measured flow velocity and the resulting flow rate are within predefined limits. These values / data are then transmitted either directly (immediately) as command data to a transmitter unit 56 (arrow 64) or indirectly via the aforementioned storage unit 54 (arrow 65 and arrow 66). The transmitter unit 56 then forwards the data or manipulated variables, in particular the flow control variable, or the flow control value, to actuators (control and regulating devices) of the high-pressure pump (arrow 67), which are not shown here. These actuators then ensure demand-driven control of the high-pressure pump.

[0044] In the Figure 3Figure 1 shows a cross-sectional view of an embodiment of a thick-walled pipe 1 with a flange 20 for mounting on a high-pressure-side outlet of a high-pressure pump (not shown here). The thick-walled pipe 1 is connected to the flange 20 with suitable sealing elements 21 to prevent leakage and has an inner diameter Di and an outer diameter Da. The flange 20 has a flow channel 22, which extends from the high-pressure-side outlet of the high-pressure pump (not shown here) to the thick-walled pipe 1. The flow channel 22 has a conical section 23, in particular a section 23 that increases conically in the flow direction S. The distal end 24 of the flow channel 22, which is oriented towards the thick-walled pipe 1, advantageously has an inner diameter di that corresponds to at least two-thirds of the inner diameter Di or the inner diameter Di of the thick-walled pipe 1.Advantageously, the inner diameter di of the flow channel 22 is the same size as the inner diameter Di of the thick-walled pipe 1.

[0045] In the Figure 4 A schematic circuit diagram of a high-pressure system 30 is shown. This is primarily a high-pressure system for the production of ethylene copolymers in reactor 31, which can advantageously be designed as a stirred reactor. Alternatively, it is conceivable that the [system] in the Figure 4The high-pressure system 30 shown comprises a tubular reactor. Ethylene and / or propylene are compressed by the compressors (primary compressor, hyper compressor) and pumped into the reactor 31. This results in the flow direction S. Upstream of the reactor 31, i.e., opposite the flow direction S, the possible high-pressure pumps 32 are arranged, which are connected to the reactor 31, in particular via their high-pressure-side high-pressure pump outlet. These high-pressure pumps 32 are advantageously used for pumping initiators (sometimes also referred to as catalysts, peroxides), modifiers, and / or comonomers. Furthermore, the high-pressure pumps 32 are advantageously used as control elements (control and regulating devices) in the high-pressure system 30, since the amount of fluid pumped in influences the polymerization process, and in some cases even initiates it. Precise metering of the fluids to the high-pressure medium ensures, among other things,It regulates the temperature and degree of polymerization, thus decisively influencing the quality of the produced plastic. Reference symbol list

[0046] 1. Thick-walled pipe 2. (First) sound path 3. (Second) sound path 10, 11 Ultrasound measuring device 20 Flange 21 Sealing element 22 Flow channel 23 Continuously conically increasing section 24 Distal end 30 High-pressure system 31a, b Reactor / Reactor chamber 32 High-pressure pump 50 Evaluation unit 51 Computing unit 52 Comparison unit 53 Deviation determination unit 54 Storage unit 55 Receiving unit 56 Transmitting unit 60 Input of measured values ​​61 Transmission of measured values ​​to processing unit 62 Transmission of measured values ​​to storage unit 63 Transmission of measured values ​​to processing unit 64 Transmission of command data to transmitting unit 65 Transmission of command data to storage unit 66 Transmission of command data to transmitting unit 67 Transmission of command data to actuators Da Outer diameter of thick-walled pipe / pipe outer diameter Di Inner diameter of thick-walled pipe / pipe inner diameter Di Inner diameter of flow channel Flow direction

Claims

1. High-pressure installation (30) comprising a high-pressure pump (32), wherein the high-pressure pump (32) is designed to generate a pressure between 1000 to 6000bar, with a high-pressure pump inlet and a high-pressure-side high-pressure pump outlet, wherein at least one ultrasonic measuring device (10, 11) is arranged externally on the high-pressure-side high-pressure pump outlet for measuring a flow velocity of a fluid flow flowing through a pipe (1) of the high-pressure-side high-pressure pump outlet, characterized in that the high-pressure installation is a high-pressure installation for polymerization, a high-pressure installation for the production of copolymers, a water jet cutting installation or a high-pressure pasteurization installation, and that the high-pressure-side high-pressure pump outlet has a thick-walled pipe (1) with a ratio of the pipe inner diameter (Di) to the pipe outer diameter (Da) of 1:1,5 to 1:5 and the ultrasonic measuring device (10, 11) is arranged on this thick-walled pipe (1).

2. High-pressure installation according to claim 1, characterized in that the high-pressure installation (30) has a reactor chamber (31) for carrying out a chemical, thermal, thermodynamic or mechanical reaction and the thick-walled pipe (1) is arranged directly or indirectly between the reactor chamber (31) and the high-pressure pump (32).

3. High-pressure installation according to one of claims 1 or 2, characterized in that the high-pressure installation (30) is an installation for polymerization of monomers, in particular of ethene (ethylene) and propene (propylene).

4. High-pressure installation according to one of claims 1 to 3, characterized in that the thick-walled pipe (1) has a material from the group of metal alloys, such as high-alloy or low-alloy steels, titanium alloys, copper alloys, nickel alloys, tantalum alloys, chromium alloys or cobalt alloys.

5. High-pressure installation according to one of claims 1 to 4, characterized in that the thick-walled pipe (1) is fixed to the high-pressure pump (32) by means of a flange (20), which flange (20) has a flow channel (22) with a section (23) that continuously widens conically at least in sections - in the flow direction -, wherein this conical section (23) extends at least over one third, in particular over half of the total length of the flow channel (22).

6. High-pressure installation according to one of claims 1 to 5, characterized in that the inner diameter (Di) of the thick-walled pipe (1) has a section that continuously widens at least in sections, a cylindrical section and a section that continuously narrows at least in sections.

7. High-pressure installation according to one of claims 1 to 6, characterized in that in the flow direction before the ultrasonic measuring device (10, 11) a straight, in particular curvature-free calming section with a length which corresponds to at least five times the inner diameter of the thick-walled pipe (1), and in the flow direction after the ultrasonic measuring device (10, 11) a straight, in particular curvature-free calming section with a length which corresponds to at least three times the inner diameter (Di) of the thick-walled pipe (1), are formed.

8. High-pressure installation according to one of claims 1 to 7, characterized in that the ultrasonic measuring device (10, 11) is connected to an evaluation unit (50) in terms of signal transmission in order to transmit the measurement result of the flow velocity of the fluid flow to the evaluation unit (50).

9. Method for determining a flow control variable of a fluid flow flowing through a high-pressure-side high-pressure pump outlet of a high-pressure pump (32) in a high-pressure installation according to at least one of the preceding claims, comprising at least the following steps: - measurement of the flow velocity of the fluid flow flowing through a pipe (1) of the high-pressure-side high-pressure pump outlet by means of at least one ultrasonic measuring device (10, 11), in particular an ultrasonic measuring device (10, 11) arranged externally, to obtain a measurement result of the flow velocity, - transmission of the measurement result of the flow velocity to an evaluation unit (50), and - calculation of a current flow value as well as the flow control variable from the measurement result of the flow velocity by means of the evaluation unit (50).

10. Method according to claim 9, characterized in that the measurement of the flow velocity as well as the transmission of the measurement result and the calculation of the current flow value as well as the flow control variable to be achieved are carried out dynamically.

11. Method according to one of the preceding claims, characterized in that the evaluation unit (50) calculates the current flow value by means of an equation method and / or the flow control variable by means of a comparison method.

12. Method according to one of the preceding claims, characterized in that the flow velocity measured by means of the ultrasonic measuring device (10, 11) is corrected taking into account further available or determined information data such as, for example, a temperature of the fluid flow and / or a pressure of the fluid flow, wherein the mathematical relationships necessary for this and, if applicable, necessary factors are determined theoretically or determined empirically.

13. Use of an ultrasonic measuring device (10, 11) for determining a flow value of a fluid flow flowing through a thick-walled pipe (1) of a high-pressure-side high-pressure pump outlet of a high-pressure pump of a high-pressure installation according to at least one of claims 1 to 8, wherein the high-pressure pump (32) is designed to generate a pressure between 1000 to 6000bar, characterized in that the ultrasonic measuring device (10, 11) is arranged externally on the thick-walled pipe (1) of the high-pressure pump outlet, which pipe (1) has a ratio of the inner diameter (Di) to the outer diameter (Da) of 1:1,5 to 1:5, such that this ultrasonic measuring device (10, 11) dynamically measures the flow velocity of the fluid flow and transmits this measured flow velocity as a measurement result to an evaluation unit (50) for calculating a current flow value as well as a flow control variable to be achieved from the measurement result.