阅读说明：本技术 用于确定体积和/或质量流率的方法 (Method for determining a volume and/or mass flow rate ) 是由 克里斯托夫·胡伯 帕特里克·赖特 于 2018-11-15 设计创作，主要内容包括：本发明涉及一种用于确定在管(20)中流动的介质(M)的体积和/或质量流率的方法,其中,流体(F)的密度和/或粘度借助于MEMS传感器芯片(30)来确定,其中在管(20)中流动的介质(M)至少部分流过MEMS传感器芯片(30)的测量通道(31),以确定流体(F)的密度和/或粘度,且其中介质(M)的体积和/或质量流率借助于跨越MEMS传感器芯片(30)的测量通道(31)检查到的压降|p2-p1|和MEMS传感器(30)确定的密度和/或粘度来确定,与介质无关。(The invention relates to a method for determining a volume and/or mass flow rate of a medium (M) flowing in a tube (20), wherein a density and/or a viscosity of a fluid (F) is determined by means of a MEMS sensor chip (30), wherein the medium (M) flowing in the tube (20) flows at least partially through a measurement channel (31) of the MEMS sensor chip (30) in order to determine the density and/or the viscosity of the fluid (F), and wherein the volume and/or the mass flow rate of the medium (M) is determined by means of a pressure drop | p2-p1| detected across the measurement channel (31) of the MEMS sensor chip (30) and the density and/or the viscosity determined by the MEMS sensor (30), independently of the medium.)

1. Method for determining a volume and/or a mass flow rate of a medium (M) flowing in a tube (20), wherein a density and/or a viscosity of a fluid (F) is determined by means of a MEMS sensor chip (30), wherein the medium (M) flowing in the tube (20) flows at least partially through a measurement channel (31) of the MEMS sensor chip (30) to determine the density and/or the viscosity of the fluid (F), and wherein the volume and/or the mass flow rate of the medium (M) is determined by means of a pressure drop | p2-p1| checked across the measurement channel (31) of the MEMS sensor chip (30) and the density and/or the viscosity determined by the MEMS sensor (30), independently of the medium.

2. Method according to claim 1, wherein the measurement channel (31) of the MEMS sensor chip (30) is connected to the tube (20) in the following way: the medium (M) flows completely through the measurement channel (31) of the MEMS sensor chip (30) such that the pressure drop | p2-p1| is substantially generated by the measurement channel (31) of the MEMS sensor chip (30).

3. Method according to claim 1, wherein an orifice plate (21) is introduced into the tube in the following way: the medium flows in parallel through the orifice plate and the measuring channel of the MEMS sensor chip, and the pressure drop (| p2-p1|) is generated by the orifice plate (21) introduced into the tube (20) and the measuring channel (31) of the MEMS sensor chip (30) through which the medium partially flows.

4. The method according to the preceding claim, wherein the orifice plate (21) and the measuring channel (31) are matched to each other in the following way: the flow ratio between the medium (M) flowing through the measuring channel (31) and the medium (M) flowing through the orifice plate (21) is set to be less than 1: 20, preferably less than 1: 100, particularly preferably less than 1: 500.

5. An apparatus for determining the volume and/or mass flow rate (1) of a medium (M) flowing in a pipe (20), comprising at least:

-a MEMS sensor chip (30), the MEMS sensor chip (30) having a measurement channel (31), the measurement channel (31) being connected to the tube (20) to determine the density and/or viscosity of the medium (M) in the following manner: the medium (M) flows at least partially through the measuring channel (31),

-a differential pressure measurement device (40), the differential pressure measurement device (40) being configured to check a pressure drop | p2-p1| across the measurement channel (31) of the MEMS sensor chip (30), and

-an evaluation unit (50), the evaluation unit (50) being provided for determining a volume and/or mass flow rate of the medium (M) on the basis of the pressure drop | p2-p1| determined by the differential pressure measurement device and the density and/or viscosity determined by the MEMS sensor chip (30), independently of the medium.

6. The device according to the preceding claim, wherein the MEMS sensor chip (30) is connected to the tube (20) in the following way: the medium (M) flows completely through the measurement channel (31) of the MEMS sensor chip (30) such that a pressure drop | p2-p1| is substantially generated by the measurement channel (31) of the MEMS sensor chip (30), and the differential pressure measurement device (40) is further designed for examining the pressure drop across the measurement channel (31) of the MEMS sensor chip (30).

7. The device according to claim 5, further comprising an orifice plate (21), the medium (M) flowing through the orifice plate (21), wherein the orifice plate (21) and the measurement channel (31) of the MEMS sensor chip (30) are introduced into the tube (20) in the following manner: the medium (M) flows through the perforated plate (21) and the measuring channel (31), preferably in parallel.

8. Device according to at least one of claims 5 to 7, wherein the measurement channel (31) of the MEMS sensor chip (30) has a flow cross section (A) with a diameter in the range of 0.03-1 mm, preferably 0.05-0.6 mm, particularly preferably 0.1-0.3 mm_{Measuring channel}) And measuring the channel.

9. The apparatus according to at least one of the claims 5 to 8, wherein the orifice plate (21) has a flow cross section (A)_{Orifice plate}) Wherein the flow cross section (A) of the orifice plate opening_{Orifice plate}) Is designed in the following way: the flow cross-section (A) flowing through the measuring channel (31)_{Measuring channel}) And flowing through the orifice plate opening (A)_{Orifice plate}) Of the flow cross section (A)_{Orifice plate}) Is set to be less than 1: 20, preferably less than 1: 100, particularly preferably less than 1: 500.

Technical Field

The present invention relates to a method for determining the volume and/or mass flow rate of a medium flowing in a pipe, and to an apparatus for determining the volume and/or mass flow rate of a medium flowing in a pipe.

Background

Devices for determining the volume flow rate according to the differential pressure principle are known per se. For example, an orifice plate is used here as an effective pressure setting device, and the pressure difference across the orifice plate is checked. The measurement itself requires the use of differential pressure measurement devices and knowledge of the characteristic values of the material, in particular viscosity, density and adiabatic index. Details for this are given in the 2004 ISO 5167-1 standard and 2003 2: defined in the 2003 standard.

A disadvantage of this method is that the measurement of the volume flow rate is dependent on the material value of the medium (dependent on the medium), and therefore must be known.

Disclosure of Invention

The object of the invention is therefore to remedy this disadvantage.

This object is achieved by the invention by a method according to claim 1 and by an apparatus according to claim 5.

In order to determine the volume and/or mass flow rate of the medium flowing in the tube, the method according to the invention proposes to determine the density and/or viscosity of the fluid by means of the MEMS sensor chip, wherein the medium flowing in the tube flows at least partially through the measurement channel of the MEMS sensor chip in order to determine the density and/or viscosity of the fluid, and wherein the volume and/or mass flow rate of the medium is determined by means of the pressure drop | p2-p1| checked across the measurement channel of the MEMS sensor chip and the density and/or viscosity determined by the MEMS sensor, independently of the medium.

MEMS sensor chips are microelectromechanical systems that are used in metrology to check one or more measured values. These MEMS sensor chips are usually produced using single-layer or multilayer wafers, in particular silicon-based wafers, using methods common in semiconductor technology, such as etching processes, oxidation methods, implantation methods, bonding methods and/or coating methods.

MEMS sensor chips for determining measured values of a flowing medium, in particular a liquid or a gas, usually have at least one measuring channel, the interior of which forms a line through which the medium flows during the measurement.

According to the invention, it is now proposed that, in parallel with a conventional volume flow rate measurement according to the differential pressure principle, the MEMS sensor chip determines the current density and/or viscosity of the medium, so that a medium-independent volume and/or mass flow rate measurement is possible.

A further development of the invention proposes that the measurement channel of the MEMS sensor chip is connected to the tube in the following way: the medium flows entirely through the measurement channel of the MEMS sensor chip such that the pressure drop | p2-p1| is substantially generated by the measurement channel of the MEMS sensor chip.

An alternative further development of the invention proposes to introduce the orifice plate into the tube in the following manner: the medium flows in parallel through the orifice plate and the measuring channel of the MEMS sensor chip, and the pressure drop | p2-p1| is generated by the orifice plate in the inlet tube and the measuring channel of the MEMS sensor chip through which the medium partially flows. Further developments may in particular provide that the orifice plate and the measuring channel are matched to one another in the following manner: the flow ratio between the medium flowing through the measuring channel and the medium flowing through the perforated plate is set to less than 1: 20, preferably less than 1: 100, particularly preferably less than 1: 500.

The device according to the invention for determining the volume and/or mass flow rate of a medium flowing in a pipe comprises at least:

a MEMS sensor chip having a measurement channel connected to the tube for determining the density and/or viscosity of the medium in the following manner: the medium flows at least partially through the measurement channel,

a differential pressure measuring device for checking the pressure drop | p2-p1| across the MEMS sensor chip measurement channel,

an evaluation unit, which is provided for determining the volume and/or mass flow rate of the medium, independently of the medium, on the basis of the pressure drop | p2-p1| determined by the differential pressure measuring device and the density and/or viscosity determined by the MEMS sensor chip.

A further development of the invention proposes that the MEMS sensor chip is connected to the tube in the following way: the medium flows completely through the measurement channel of the MEMS sensor chip, so that the pressure drop | p2-p1| is essentially generated by the measurement channel of the MEMS sensor chip, and the differential pressure measurement device is further designed for examining the pressure drop across the measurement channel of the MEMS sensor chip.

An alternative further development of the invention proposes for this purpose that the device further has an orifice plate through which the medium flows, wherein the orifice plate and the measuring channel of the MEMS sensor chip are introduced into the tube in the following manner: the medium flows, preferably in parallel, through both the orifice plate and the channel.

A further development of the invention proposes that the measuring channel of the MEMS sensor chip has a flow cross section A with a diameter in the range from 0.03 to 1 mm, preferably from 0.05 to 0.6 mm, particularly preferably from 0.1 to 0.3 mm_{Measuring channel}。

According to a further development of the invention, the perforated plate has a flow cross section A_{Orifice plate}Wherein the flow cross section A of the orifice plate opening_{Orifice plate}Is designed in the following way: flow cross section A through the measuring channel_{Measuring channel}And a flow cross section A through the openings of the perforated plate_{Orifice plate}Is set to a flow ratio of less than 1: 20, preferably less than 1: 100, particularly preferably less than 1: 500.

Drawings

The invention is explained in more detail with reference to the following figures. Shown in the attached drawings:

FIG. 1: a first exemplary embodiment of the invention, and

FIG. 2: a second exemplary embodiment of the present invention that replaces the first embodiment.

Detailed Description

Fig. 1 shows a first exemplary embodiment of the present invention. In this case, the device 1 for determining a volume and/or mass flow rate comprises a differential pressure measuring device 40 for determining the volume flow rate, the differential pressure measuring device 40 being constructed according to the principle of the effective pressure setting device and having an orifice 21 in the pipe 20, through which pipe 20 the medium M flows. The tube 20 generally has a flow cross-section A_PipeTheir diameter ranges from < 30 mm, preferably < 10 mm, particularly preferably < 5 mm. An orifice plate 21 is introduced into the tube 20 in the flow direction as an effective pressure setting device. The orifice plate 21 has an opening or flow cross section A_{Orifice plate}The orifice plate openings of (a) are usually 0.2 to 10 mm, preferably 0.4 to 5 mm, particularly preferably 0.7 to 2mm in diameter. In addition to the flow path of the medium M through the orifice plate 21, a MEMS sensor chip 30 for determining the density and/or viscosity of the medium M is connected to the tube 20 in a flow path parallel to the path. The MEMS sensor chip 30 has a measurement channel 31 through which the medium M flows during the measurement, so that the MEMS sensor chip 30 can determine the density and/or the viscosity of the medium M. The measuring channel 31 generally has a flow cross section A with a diameter in the range from 0.03 to 1 mm, preferably from 0.05 to 0.6 mm, particularly preferably from 0.1 to 0.3 mm_{Measuring channel}。

In principle, the MEMS sensor chip 30 operates with an oscillatable unit, the oscillation behavior of which is examined in order to determine the density and/or viscosity. In this case, the Q factor of the oscillation of the oscillatable unit may be used to determine, for example, the viscosity of the medium M. Depending on the medium M, the oscillatable units of the MEMS sensor chip 30 may be designed differently. In the case of a medium M containing a gas, the oscillatable unit may be designed in the form of, for example, a cantilever or a crystal oscillator, while in the case of a medium M containing a liquid, the oscillatable unit may be designed to be excited to oscillate in the form of an oscillating measuring channel 31. In both cases, use is made of the fact that at least one characteristic of the oscillation of the oscillatable unit varies due to the density and/or viscosity of the medium M so that the density and/or viscosity can be determined.

The device 1 for determining a volume and/or mass flow rate further comprises an evaluation unit 50, which evaluation unit 50 is provided for determining the volume and/or mass flow rate of the medium, independently of the medium, on the basis of the pressure drop | p2-p1| determined by the differential pressure measurement means 40 and the density and/or viscosity determined by the MEMS sensor chip 30. For this purpose, the evaluation unit 50 can determine the volumetric flow rate through the pipe based on the determined pressure drop | p2-p1| and the viscosity according to the Hagen-Poiseuille law. Furthermore, the evaluation unit 50 may also determine the mass flow rate through the tube 20 based on the determined density.

Fig. 2 shows a second exemplary embodiment of the invention, which is an alternative to the first exemplary embodiment. The device 1 for determining a volume/mass flow rate differs from the first exemplary embodiment in that it is designed in such a way that the medium M flows completely through the measuring channel 31 of the MEMS sensor chip 30, although a differential pressure measuring device 40 is also provided here, in this case without an orifice plate. This means that the differential pressure measuring device 40 is thus designed in the following way: only the first pressure p1 before the measurement channel of the MEMS sensor chip and the second pressure p2 after the measurement channel of the MEMS sensor chip are checked to determine the pressure drop | p2-p1 |.

Reference symbols

Device for determining a volume and/or mass flow rate

20 tubes

21 orifice plate

30 MEMS sensor chip for determining density and/or viscosity

31 measurement channel of MEMS sensor

40 apparatus for determining a pressure drop

50 evaluation unit

A_{Orifice plate}Flow cross section of orifice plate opening

A_{Measuring channel}Measuring the flow cross section of a channel

A_PipeFlow cross section of pipe

| p2-p1| pressure drop values

M medium