JP2022539319A - Time-resolved once-through process measurement system for media and method for determining thermal expansion coefficient using the system - Google Patents

Abstract

The present invention is located between the inlet (12), the outlet (14), and the inlet (12) and the outlet (14) and comprises at least a pump (48), a density sensor (50) and a temperature sensor (51). , and a flow meter (10) comprising electrical or electronic components. So that the density does not have to be measured at exactly the same temperature as the volume, the present invention provides the density sensor (50) or a conduit section (56) leading to the density sensor (50) immediately upstream of the density sensor (50). , is in heat-conducting contact with heat-generating electrical or electronic components, and the rotational speed of the pump (48) is controlled. Correspondingly, the present invention relates to a method for determining the coefficient of thermal expansion, in which the density and temperature of a medium heated in a heat-generating electrical or electronic component are determined at two different rotational speeds of the pump (48). Measured with sensor (50) and temperature sensor (51), the thermal expansion coefficient is calculated from the density sensor (50) measurements and the corresponding temperature sensor (51) measurements. [Selection diagram] Fig. 1

Description

The present invention is a time-resolved flow-through process for media comprising an inlet, an outlet, and a flow meter positioned between the inlet and the outlet and comprising at least a pump, a density sensor, a temperature sensor, and electrical or electronic components. It relates to a measurement system and a method for determining the coefficient of thermal expansion using a time-resolved once-through process measurement system for media.

Systems of this kind have been known for many years and are used, for example, for injection quantity measurement in internal combustion engines. For example, DE 1798080 describes an electronically controlled flow meter with an inlet and an outlet, between which a rotating displacer in the form of a gear pump is arranged and parallel to the displacer. A piston is arranged in the measuring chamber in the conduit. To determine the flow rate, the displacement of the piston within the measuring chamber is measured using an optical sensor. The speed of the gear pump is continuously readjusted in the evaluation control unit on the basis of this signal so that whenever possible the piston is always returned to the starting position and only a small flow occurs in the bypass conduit. . Thus, the flow rate within a specified time interval is calculated from the number of revolutions or partial revolutions of the gear pump as measured by the encoder and the known pumped volume of the gear pump during one revolution.

A flow measuring device constructed in such a manner is also described in DE 103 31 228 B1. To determine an accurate injection flow curve, the gear pumps are each set to a constant speed before injection begins and the piston motion is then measured and used to determine the injection curve.

In order to further avoid measurement errors due to variations in the density of the medium being measured, a system for measuring time-resolved flow-through processes of a medium is described in EP-A-3073228, hereby incorporated by reference. In order to provide an accurate statement of the existing density of the medium being measured at precise timing, the flowmeter conduit section is bypassable using a bypass conduit in which the pump and density sensor are arranged in series. , the density can be used to calculate the mass flow rate from the measured volumetric flow rate.

It is also known from DE 102010045521 to determine the thermal expansion of the fuel by introducing it into a measuring volume and supplying it with energy in the measuring volume. The pressure is measured at the initial and final conditions and the thermal expansion is calculated from the pressure difference. The measurements thus obtained can also be used to draw conclusions about the mixture of substances used.

In the measuring instruments currently available on the market, attempts are made to determine the density as accurately as possible at the temperature at which the volumetric flow-through is also measured, in order to avoid conversion to the temperature at which the volumetric flow-through is measured. The reason is that the exact coefficients of thermal expansion must be known for such transformations. Transformation of the measured volumetric through-flow into a volumetric through-flow at a reference temperature is also not possible without a coefficient of thermal expansion, so that a corresponding pretreatment of the medium is necessary. However, prior determination of the coefficient of thermal expansion has been shown to be insufficient in many cases, since the composition of the medium being measured varies to some extent. Furthermore, especially due to miniaturization, there are often heat-generating components in the vicinity of the density sensor, which causes the problem that the temperature at the density sensor differs from the temperature of the medium at the flowmeter itself. This creates the need for conversion to volume or density at gear temperature, for which the exact coefficient of expansion must be known.

German Patent No. 1798080 European Patent Publication No. 3073228 DE 102010045521

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a time-resolved once-through process measurement system for media, as well as a method for determining the coefficient of thermal expansion using the system, with which additional measuring devices can be used for this purpose. or the need to measure a separate sample, the coefficient of thermal expansion can be determined as accurately as possible and used in standardized volumetric flow-through or mass flow calculations. Measurement results are improved compared to systems and methods. In particular, the aim is to avoid the need to measure density at exactly the same temperature as volume in order to obtain accurate measurements.

This problem is solved with a time-resolved once-through process measurement system for media having the features of claim 1 and a method for determining the coefficient of thermal expansion using the system according to claim 11 .

With respect to a time-resolved once-through process measurement system for media, the object is that the density sensor, or a conduit section leading to the density sensor just upstream of the density sensor, is in thermally conductive contact with a heat-generating electrical or electronic component, and the pump is speed-resolved. resolved in terms of being controlled. This is because with such a mechanism it is possible to carry out the method according to the invention, in which the density and temperature of the medium heated in the heat-generating electrical or electronic component varies depending on the pump are measured with the density and temperature sensors at two different rotational speeds of , and the coefficient of thermal expansion is calculated from the density sensor measurements and the associated temperature sensor measurements. Usually the rotational speed is changed permanently and a number of measurements are taken accordingly. This calculation is then performed for two different measurements at two different velocities, for example using the formula: γ=1/(T ₂ −T ₁ )(ρ ₁ /ρ ₂ −1). will be The temperature sensor is often integrated into the density sensor, so the measured temperature also corresponds to the temperature at the density sensor. First, a measurement is taken at the first specified rotational speed of the pump. This means that the medium reaches the density sensor at a first temperature, which is slightly higher because the density sensor or the conduit leading directly to the density sensor is in heat-conducting contact with the heat-generating component. Thus, a first density is measured for a first temperature above the temperature of the medium conveyed in the rest of the flow meter. If, for example, the pump is then sped up, more cold medium will be circulated out of the flow meter, which will correspondingly act as a heat sink, resulting in a drop in temperature at the temperature sensor and at the heat source. Density sensors that are in close proximity, ie located at the location of the heat-generating component, result in different densities, resulting in different densities than the initial measurement. Therefore, by varying the speed of the pump, multiple measurements can be made at different temperatures, thus allowing the coefficient of thermal expansion to be calculated very accurately in a highly dynamic manner. Thus, this mechanism can be used to actively track fluid properties within the flow meter.

It is also advantageous if the density sensor has a particularly controllable heat source. That is, the heat source is preferably integrated into the density sensor. In this case the heat source is controlled instead of the amount of fluid circulated. This can then be regarded as equivalent to circulation rate control with a pump, so that the pump will rotate at a constant speed. A combination of both control schemes is of course also possible. Although this increases complexity, it makes the temperature control more flexible and allows a higher level of integration to be achieved.

Preferably, the flow meter comprises a main conduit through which the inlet is fluidly connected to the outlet, a displacer disposed within the main conduit, the main conduit being bypassable with a bypass conduit, the bypass conduit branches from the main conduit between the inlet and the displacer and opens into the main conduit between the displacer and the outlet, a pressure differential transducer is located in the bypass conduit, the displacer detects the pressure differential present in the pressure differential transducer Driven by a drive motor controllable by an electronic unit, depending on the heat generation, the drive motor of the displacer or the electronic unit is in thermal conductive contact with the density sensor or with the conduit leading to the density sensor just upstream of the density sensor. acts as an electrical or electronic component that Accordingly, the medium is heated in the electronic unit of the displacer and/or the drive motor in the conduit section leading to the density sensor immediately upstream of or at the density sensor. Such a flow meter operates with high accuracy and can be implemented within a relatively small installation space. Using electronic and/or electrical components as the heat source for tracking the fluid characteristic curve eliminates additional components for determining the coefficient of thermal expansion.

In a preferred further development of the system, the conduit section of the main conduit or the bypass conduit can be bypassed using a second bypass conduit in which said pump and density sensor are arranged in series. Thus, circulation occurs in the bypass so that the density of the medium can be determined during the measurement without feedback effects on the measurement circuit. The medium absorbs heat from the bypassed conduit section of the main conduit or from the bypassed conduit. The medium that is not heated in the electronic component, ie the main flow in the bypass line or main conduit, accordingly acts as a heat sink, whereby the circulated medium flow is cooled again.

Preferably, the pump is driven via a second drive motor and is controllable with a control unit, the control unit and/or the drive motor connecting to the density sensor or a conduit leading to the density sensor immediately upstream of the density sensor. Acts as a heat-generating electrical or electronic component in thermally conductive contact with the part. The second drive motor is controlled by a control unit with at least two different speeds in order to be able to determine the possible coefficient of thermal expansion from the two measurements. This thermal expansion coefficient determination becomes more accurate as the number of measurements taken at different speeds of the pump increases.

Also in that way, with respect to the method, the medium can be heated in the second drive motor and/or the control unit of the pump in the conduit section of the bypass line upstream of the density sensor or at the location of the density sensor. The drive motor or control unit of the pump thus plays the role of the heat source and thus provides the possibility of operating along a characteristic curve. Thus, in addition to driving the displacer, the driving of the pump can also directly serve as a heat source, whichever is preferred from a system design point of view. Also, the medium can additionally or alternatively be heated with a heating element dedicated for this purpose.

In order to eliminate the effects on the flow meter readings, and in particular on the pressure differential transducers, as a result of the bypass line, the pump is configured to be pulsation free, in particular as a Tesla pump. This also eliminates errors in the measurements of the density sensor, which, for example when designed as a MEMS sensor or in the case of a sensor visible to the naked eye, is excited to oscillate itself due to pulsations in the medium. there is a possibility. Tesla pumps simply use viscous forces to convey fluid based on the existing viscosity of the fluid, without the need to use vanes. For this purpose, several discs arranged side by side are rotated by a drive motor, between which the medium is introduced centrally, so that due to the viscosity and sticking due to the outwardly increasing speed, The medium is conveyed tangentially in the direction of rotation and radially outward. This results in efficient, pulseless delivery.

In a more advanced embodiment, the Tesla pump is placed upstream of the density sensor in the bypass conduit in the conveying direction of the medium, thereby preventing air bubbles from reaching the pump in the area of the sensor during start-up. Such air bubbles cannot be transported in Tesla pumps due to insufficient cohesion of the medium, otherwise they would greatly reduce the efficiency of the pump.

It is also advantageous if the second bypass conduit branches from the first bypass conduit between the inlet and the pressure differential transducer and opens into the first bypass conduit. On the one hand, this position is very accessible, so that short connecting lines are sufficient, and on the other hand, the medium can be circulated directly without creating a flow in the measuring chamber, thus preventing any influence on the measurement of the flowmeter.

The temperature sensor is integrated into the density sensor in order to measure the temperature at the same place as the density on the one hand and to simplify the mechanics of the system on the other hand.

A simplification of the structure of the system is also achieved in that the control unit of the second drive motor of the pump is integrated into the electronic unit.

Accordingly, a time-resolved once-through process measurement system for media and a method for determining the coefficient of thermal expansion using the system are provided for determining the coefficient of thermal expansion of media in a highly dynamic manner and with high accuracy. In addition, the fluid characteristic curve of each medium used can be traced directly on the flow meter. The values obtained can therefore be used in the calculations of the mass and volumetric flow-through determined in the flowmeter, so they also have a higher accuracy. No additional components are required for this purpose. Instead, in tracing the characteristic curve, the part that produces heat anyway is used as the heat source and the cooler medium is used as the heat sink.

A time-resolved once-through process measurement system for media according to the invention, as well as a method for determining the coefficient of thermal expansion using the system, will be described below on the basis of non-limiting example embodiments shown in the figures.

1 is a schematic diagram of the basic structure of a time-resolved once-through process measurement system for media according to the present invention; FIG. 1 is a perspective view of a media time-resolved flow-through process measurement system with the body partially cut open; FIG.

A time-resolved once-through process measurement system for a medium according to the invention, shown in FIG. Conduit section 18 of flow meter 10 is bypassable.

Through the inlet 12 , the medium to be measured, in particular fuel, flows from the device that produces the flow entering the main conduit 20 of the flowmeter 10 . A rotary displacer 22 in the form of a double gear pump is arranged within this main conduit 20 . Downstream of displacer 22 , main conduit 20 terminates at outlet 14 . The rotary displacer 22 is driven by a drive motor 24 coupled to a joint or gearbox and the drive motor 24 is controlled by an electronic unit 25 .

A first bypass conduit 26 branches off the main conduit 20 between the inlet 12 and the rotary displacer 22 and opens back into the main conduit 20 downstream of the rotary displacer 22 between the rotary displacer 22 and the outlet 14 to provide a main conduit. It is fluidly connected to inlet 12 and outlet 14 as well as tube 20 . A translational pressure differential transducer 28 is arranged in this bypass line 26 and consists of a measuring chamber 30 and a freely displaceable piston 32 arranged in the measuring chamber 30, the piston 32 displacing the measuring medium. , ie fuel, and is cylindrical in shape like the measuring chamber 30 , so that the measuring chamber 30 has an inner diameter substantially corresponding to the outer diameter of the piston 32 . Application of a pressure differential between the front and rear sides of the piston 32 causes displacement of the piston 32 from its rest position. The displacement of piston 32 is therefore a function of the applied pressure differential. A displacement sensor 34 is arranged in the measuring chamber 30 and is operatively connected with the piston 32 in which a voltage is generated which depends on the magnitude of the displacement of the piston 32 . This displacement sensor 34 is mounted in the measuring chamber 30 and is in particular a magnetoresistive sensor which converts the field strength of the magnet 36 acting on it into a voltage. For this purpose a magnet 36 is attached to the center of gravity of the piston 32 . However, an optical sensor may be used as the displacement sensor 34 .

The displacement sensor 34 is also connected to an electronic unit 25, which is accordingly used to evaluate the measured value of the displacement sensor 34 and convert it into a control signal to the drive motor 24, the drive motor 24 is controlled so that the piston 32 is always in a defined starting position. The rotary displacer 22 thus always substantially compensates for the pressure difference occurring at the piston 32 due to the injected medium at all times of the transport. This means that if the piston 32 is displaced to the right, the pump speed will be increased as a function of the magnitude of this displacement and vice versa. For this purpose, the displacement of the piston 32, or the volume displaced by it in the measuring chamber 30, is converted by a transfer function into the required delivery volume of the rotary displacer 22 or the speed of the drive motor 24, and correspondingly Current is supplied to the drive motor 24 . However, the electronic unit 25 also contains heat-generating power semiconductors for driving the drive motor 24 .

A pressure-measuring element 40 is arranged in the measuring chamber 30 and a temperature-measuring element 42 is arranged directly behind the rotary displacer 22 and continuously measures the pressure and temperature occurring in this area and measures They are then supplied to the electronic unit 25 so that the density variations in the chamber 30 can be taken into account in the calculations.

A series of measurements was taken to calculate the total flow rate determined by the electronic unit 25, the flow rate in the bypass line 26 due to the movement or position of the piston 32 and the volume displaced within the measuring chamber 30, and the flow rate for a fixed time. Both the actual flow rate of the rotating displacer 22 within the interval are considered and implemented to add both flow rates together to determine the total flow rate.

The flow rate at the piston 32 is determined, for example, by differentiating the displacement of the piston 32 in an electronic unit 25 connected to a displacement sensor 34 and then multiplying it by the base area of the piston 32 to obtain the value in the bypass line 26 during said time interval. is determined by obtaining the volumetric flow-through of

The flow rate through the rotary displacer 22, and thus the main conduit 20, can be determined from determined control data for controlling the displacer 22, or can be determined at the displacer 22 or the drive motor 24, for example by optical encoders or magnetoresistive sensors. It can also be calculated using the rotational speed as measured directly.

In this embodiment, the second bypass conduit 16 branches off from the bypass conduit 26 between the inlet 12 and the measurement chamber 30 , bypasses the conduit section 18 and reenters the bypass conduit 26 upstream of the measurement chamber 30 . The second bypass conduit 16 may be branched and re-entered at any other location in the main conduit 20 or bypass conduit 26 , although the second bypass conduit 16 includes both the displacer 22 and the pressure differential transducer 28 . should not be bypassed either.

A non-pulsating pump 48 in the form of a Tesla pump and a density sensor 50 are arranged in series following each other in the bypass conduit 16 between the branch 44 and the opening 46 to the bypass conduit 26 . A temperature sensor 51 is also typically included within the density sensor 50 so that the temperature at which the density is measured is known exactly. This density sensor 50 may for example be defined as a MEMS sensor measuring according to the Coriolis principle. The Tesla pump 48 is driven by a second drive motor 52 , which is controlled by a control unit 54 , which in this embodiment is integrated into the electronic unit 25 . The second drive motor 52 and the density sensor 50 comprising the temperature sensor 51 are thus electrically connected to the electronic unit 25 so that the measurements of the density sensor 50 are used to convert the calculated flow value to the medium. , the Tesla pump 48 can be controlled to ensure flow through the density sensor 50, the measurement of which is otherwise within the measurement chamber due to flow stagnation. deviation from the actual value measured in The pulseless delivery of Tesla pump 48 also prevents sensor 50 readings from being erroneous.

This is because sensor 50 always oscillates at a precisely defined frequency, which depends on the design of the sensor. MEMS sensors have much higher oscillation frequencies than conventional sensors due to their compact design. For typical density sensors, the oscillation frequency is between 100 Hz and 1 kHz, and for MEMS sensors it is typically 1 kHz or higher. Thus, if the Tesla pump 48 now produces a pulsation close to the oscillation frequency of the sensor 50, the sensor 50 will be disturbed and pulsation of the pump should be avoided. Conduit portion 18 of bypass conduit 26 is thus bypassed using second bypass conduit 16 when pumped by Tesla pump 48, and from opening 46 of bypass conduit 16 to bypass conduit 26 to branch 44, conduit creating a circuit flow across the portion 18 , especially because the rotary displacer 22 ideally fully compensates for the pressure differential across the piston 32 , so ideally no flow occurs in the bypass conduit 26 . is.

The flow cross-section of the bypass conduit 26 of the flow meter 10 is significantly larger than the cross-section of the second bypass conduit 16, which has a diameter of, for example, about 4 mm, so a comparative A small amount of flow is sufficient. The lack of pulsation of the pump 48 and such lower amount of flow ensures that there is substantially no feedback effect on the control circuitry of the displacer 22 and pressure differential transducer 28 due to unwanted flow or pulsation. Guaranteed. Accurate additional information is thus supplied to the electronic unit 25, which can be used both in the control of the displacer 22 and in the calculation of the flow-through, thereby further improving the results.

In order to be able to use the measurements of the density sensor 50, this sensor 50 detects the density of the medium at exactly the same temperature as the temperature at which the flowmeter 10 operates, i.e. the temperature present in the measuring chamber 30 or the displacer 22. It is necessary to measure However, this is usually not the case because the temperature, and therefore the density, at different locations in the system, usually through ambient heat, can differ, which causes measurement deviations. This is further compounded by the demand for smaller measuring devices due to the increased influence of heat generating components, such as from the electronic unit 25, on the sensors 50,51. This is especially true at low flow rates, since then only a small amount of fresh conditioned medium is conveyed into the sensor 50 . As a result, even the smallest heat source is sufficient to cause significant heating of the medium. It is possible to condition the entire sensor in a separate conditioning path, thereby reducing this effect. However, this presents a significant limitation of sensor 50, especially in mobile applications, as there is no conditioning circuitry that can be connected to the sensor.

In order to still be able to use the measured values, a transformation of the determined volumetric through-flow is required, thereby compensating for the temperature difference in this case and the resulting volume difference. However, for such transformations the coefficient of thermal expansion of each medium used must be known. This is also required whenever the measurement volume for a particular reference temperature has to be determined. In the past, samples were sent to laboratories to determine the coefficient of thermal expansion, but this is necessary because the composition of the fuel to be measured changes frequently, and there is therefore a demand for highly dynamic determination of the coefficient of expansion. Today it is no longer enough.

In accordance with the present invention, the density sensor 50 or the conduit portion 56 of the second bypass conduit 16 leading directly to the density sensor 50 may be coupled to heat-generating components of an existing system or heat-transferred to determine the coefficient of thermal expansion. It is placed near it to generate heat, so that each heat-generating component acts as a heat source.

In this embodiment, in FIG. 2, the density sensor 50 and the second bypass conduit 16 leading to the density sensor 50 are arranged such that heat transfer to the medium occurs and the electronic unit 25 and the drive motor 24 act as heat sources. It can be seen that the conduit section 56 is arranged near the drive motor 24 and the electronic unit 25 of the displacer 22 . As a result, the medium reaching density sensor 50 has a slightly higher temperature than the medium in bypass conduit 26 and main conduit 20 and measuring chamber 30 . This difference is now used to drive at least two, but usually several, Tesla pumps 48 at different speeds to operate along the temperature characteristic curve of the medium. These different velocities result in different temperatures at the density sensor 50 and also at the temperature sensor 51, because as the flow rate increases, the effect of the cooler medium injected from the bypass line 26 acting as a heat sink increases. , and also because the influence of the heat source formed in the electronic unit 25 is reduced, since this heat source acts on the medium for a shorter time. In this way different densities at different temperatures can be measured with the density sensor 50 and thus with the temperature sensor 51, from which the formula: γ=1/(T ₂ −T ₁ )(ρ ₁ / ρ ₂ −1), it is already possible to calculate the coefficient of thermal expansion for two different temperatures. A larger number of measurements are taken, as a result of which the entire characteristic curve can be traced and the larger temperature spectrum can be used to determine the coefficient of thermal expansion, especially for nonlinear media with non-constant coefficients of thermal expansion. In this case, the accuracy of the determined coefficient of thermal expansion is improved. For example, in solutions containing water, the coefficient of expansion varies greatly with temperature, so such solutions should be subjected to the maximum possible number of measurements. It is also possible to weight each determined density and temperature value pair, which can, for example, reduce the influence of older measurements, so that after a certain period of time the older value pairs are associated with thermal Not taken into account when determining the coefficient of expansion.

Further, if the corresponding known fuel characteristic curve is stored, characteristic curve tracing can be used to determine the composition of the fuel used. It is also possible to fully evaluate characteristic curves with slope changes or reversal points, as is the case, for example, with water.

In summary, a method for determining the coefficient of thermal expansion and a time-resolved once-through process measurement system for media suitable for the method are provided, which can be used to determine the coefficient of thermal expansion highly dynamically in existing equipment and to jet it. It can be used in fuel quantity calculations to further improve the accuracy of the results. Using this method eliminates the need to measure density at the exact temperature at which volume is measured, as the coefficient of expansion is available for conversion. This is necessary in particular for the steady miniaturization of measuring instruments. Convertible to reference temperature.

The flow meter thus continuously calculates with high accuracy the flow-through process highly resolved in time, in particular with respect to the thermal expansion coefficient of the medium, compared with known configurations, for controlling the system or measuring results. provide additional data to assess

It will be clear that the invention is not limited to the embodiments described, but that various modifications are possible within the scope of protection of the main claims. In principle, other continuously operating flow meters could be used, or bypass conduits could bypass the corresponding conduit section at another location in the flow meter. Other components such as the drive motor or control unit of the Tesla pump are also used as heat sources. In other flow meters, other heat generating components are used for the purpose of tracking the characteristic curve.

Claims (15)

an inlet (12);
an outlet (14);
A flow meter (10) disposed between said inlet (12) and said outlet (14) and comprising at least a pump (48), a density sensor (50), a temperature sensor (51) and electrical or electronic components )When,
A time-resolved once-through process measurement system for media, comprising:
Said density sensor (50), or a conduit (56) leading to said density sensor (50) immediately upstream of said density sensor (50), is in thermally conductive contact with said heat-generating electrical or electronic component, said pump (48) is velocity controlled,
A system characterized by: Said flow meter (10) comprises a main conduit (20) through which said inlet (12) is fluidly connected to said outlet (14) and a displacer ( 22) is arranged, said main conduit (20) being bypassable with a bypass conduit (26), said bypass conduit (26) being between said inlet (12) and said displacer (22). branching from said main conduit (20) and opening into said main conduit (20) between said displacer (22) and said outlet (14);
a pressure differential transducer (28) is positioned within said bypass conduit (26);
said displacer (22) is drivable by a drive motor (24) controllable by an electronic unit (25) depending on the pressure differential present across said pressure differential transducer (28);
Said drive motor (24) or said electronic unit (25) of said displacer (22) is connected to said density sensor (50) or said conduit section leading to said density sensor (50) immediately upstream of said density sensor (50). 56) acting as a heat-generating electrical or electronic component in thermally conductive contact with
A time-resolved once-through process measurement system for a medium according to claim 1, characterized in that: The conduit portion (18) of said main conduit (20) or said bypass conduit (26) employs a second bypass conduit (16) in which said pump (48) and said density sensor (50) are arranged in series. can be bypassed by
3. A time-resolved once-through process measurement system for a medium according to claim 1 or 2, characterized in that: Said pump (48) is driven via a second drive motor (52) and is controllable by a control unit (54), said control unit (54) and/or said drive motor (52) , acting as a heat generating electrical or electronic component in thermal conductive contact with said density sensor (50) or said conduit (56) leading to said density sensor (50) immediately upstream of said density sensor (50);
A time-resolved once-through process measurement system for a medium according to any one of claims 1 to 3, characterized in that: wherein said pump (48) is a non-pulsating pump;
A time-resolved once-through process measurement system for a medium according to claim 4, characterized in that: wherein said non-pulsating pump (48) is a Tesla pump;
A time-resolved once-through process measurement system for a medium according to claim 5, characterized in that: said Tesla pump (48) is arranged upstream of said density sensor (50) in the conveying direction;
A time-resolved once-through process measurement system for a medium according to claim 6, characterized in that: said second bypass conduit (16) branches from said bypass conduit (26) between said inlet (12) and said pressure differential transducer (28) and opens into said bypass conduit (26);
A time-resolved once-through process measurement system for a medium according to any one of claims 3 to 7, characterized in that: wherein said temperature sensor (51) is integrated into said density sensor (50);
A time-resolved once-through process measurement system for a medium according to any one of claims 1 to 8, characterized in that: said control unit (54) of said second drive motor (52) of said pump (48) is integrated in said electronic unit (25);
A time-resolved once-through process measurement system for media according to any one of claims 1 to 9, characterized in that: A method for determining the thermal expansion coefficient of a medium according to any one of claims 1 to 10 using a time-resolved once-through process measurement system, comprising:
The density and temperature of the medium heated by the heat-generating electrical or electronic component are measured with a density sensor (50) and a temperature sensor (51) at two different rotational speeds of the pump (48), said coefficient of thermal expansion being , calculated from the density sensor (50) measurements and the corresponding temperature sensor (51) measurements,
A method characterized by: 12. A method for determining a coefficient of thermal expansion according to claim 11 using a time-resolved once-through process measurement system for the medium of claim 2, comprising:
the electronic unit (25) of the pump (48) in a conduit section (56) leading to said density sensor (50) immediately upstream of said density sensor (50) or at the location of said density sensor (50), and / or heated by the second drive motor (52),
A method characterized by: A method for determining the coefficient of thermal expansion according to claim 11 or 12 using a time-resolved once-through process measurement system for the medium according to claim 3,
the medium from the bypassable conduit portion (18) of the main conduit (20) or the bypass conduit (26) absorbs heat from the medium flow in the secondary bypass conduit (16);
A method characterized by: A thermal expansion coefficient method according to any one of claims 11 to 13, comprising a time-resolved once-through process measurement system for the medium according to claim 4,
Said pump (48) is driven by a second drive motor (52), said second drive motor (52) actuating said temperature and said density measurements to said density sensor (50) and said temperature sensor (51). controlled in a control unit (54) with at least two different speeds performed by
A method characterized by: 15. A method for determining a coefficient of thermal expansion according to claim 14 using a time-resolved once-through process measurement system for the medium of claim 4, comprising:
a second drive motor (52) of said pump in a conduit section (56) of a second bypass conduit (16) where said medium is upstream of or at said density sensor (50); and/or heated in the control unit (54) of the second drive motor (52),
A method characterized by:

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