CN206945069U - a mass flow meter - Google Patents

Abstract

The utility model discloses a mass flowmeter can combine with an inclination sensor, and this inclination sensor can detect the inclination angle of at least a part of mass flowmeter for at least a reference axis, according to this detected inclination angle, points out the mass flowmeter's of the fluid mass velocity of flow that flows through this sensor output signal, can obtain the compensation to remedy any inaccurate about with the orientation that mass flowmeter was installed; these inaccuracies in providing compensation include thermosiphon effects and fluid buoyancy effects; by compensating for these inaccuracies, the mass flow meter can be used in any orientation and non-inertial environment, improving ease of use.

Description

a mass flow meter

technical field

The utility model relates to the technical field of flow meters, in particular to a mass flow meter.

Background technique

Mass flow meters have long been known in the art. Also, it is known in the art that the orientation of a mass flow meter can affect its performance. For example, the accuracy of a mass flow meter may vary significantly from one orientation to another due to a phenomenon known as the recirculation effect. Although attempts have been made to mitigate the effects of recirculation using many different mass flow meter designs, in general the degree of reduction depends on the particular orientation in which the mass flow meter is installed and used for which it is designed to be used. .

Therefore, it is necessary to design a new mass flow meter to solve the above technical problems.

Utility model content

Aiming at the problems existing in the background technology, the purpose of the utility model is to provide a mass flow meter, which can be used in any orientation and non-inertial environment, and improves the convenience of use.

The technical scheme of the utility model is realized as follows: a mass flowmeter has a fluid inlet and a fluid outlet, including a thermal mass flow sensor, an inclination sensor, a controller and adjacent fluid flow paths, and the thermal mass flow sensor is used for To provide a first electronic signal of the mass flow rate of fluid passing between the fluid inlet and the fluid outlet, the thermal mass flow sensor has a sensor inlet portion fluidly connected to the fluid inlet, a sensor outlet portion fluidly connected to the fluid outlet, and a placement and is fluidly connected to the sensor measuring part between the sensor inlet part and the sensor outlet part; the inclination sensor is used to provide at least one second electronic signal to provide the sensor inlet part, the sensor outlet part, and the sensor measuring part The inclination angle of at least one relative to at least one reference axis; the controller is used to receive the first electronic signal and the second electronic signal, calculate the correction factor according to the second electronic signal, and apply the correction factor to the first electronic signal to obtain providing a third electronic signal for providing a mass flow rate of fluid flowing between the fluid inlet and the fluid outlet to compensate for an inclination angle of at least one sensor portion relative to at least one reference axis; the adjacent A fluid flow path having a flow path inlet positioned adjacent to the sensor inlet and fluidly connected to the fluid inlet, and a flow path outlet positioned adjacent to the sensor outlet and fluidly connected to the fluid outlet.

In the above technical solution, it further comprises a bypass pipe placed in an adjacent fluid flow path.

In the above technical solution, the third electronic signal is used to compensate for recirculation between the thermal mass flow sensor and adjacent fluid flow channels.

In the above technical solution, the second electronic signal is used to provide the inclination angle of the sensor measuring portion relative to at least one reference axis, and the third electronic signal is used to compensate for the re-occurrence between the thermal mass flow sensor and the adjacent fluid flow path. cycle.

The mass flowmeter of the utility model can be combined with an inclination sensor. The inclination sensor can detect the inclination angle of at least a part of the mass flowmeter relative to at least one reference axis. According to the detected inclination angle, point out the flow The output signal of the mass flowmeter for the mass flow rate of the fluid passing through the sensor can be compensated for any inaccuracies related to the orientation in which the mass flowmeter is installed; providing compensation for these inaccuracies, including thermosiphon effects and fluid buoyancy effects . By compensating for these inaccuracies, mass flow meters can be used in any orientation and in non-inertial environments, improving ease of use.

Description of drawings

Fig. 1 is the functional block diagram according to the utility model mass flow meter;

Figure 2 is a flow chart of a conventional compensation method.

detailed description

The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. example. Based on the embodiments of the present utility model, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the scope of protection of the present utility model.

As shown in FIG. 1 , a mass flow meter 300 of the present invention includes a base 310 with a fluid inlet 320 and a fluid outlet 330 , a thermal mass flow sensor 346 , and some related electronic components 360 .

The thermal mass flow sensor 346 includes: a sensor inlet portion 346A, which is fluidly connected to the fluid inlet 320 to accommodate a portion of the process fluid contained in the fluid inlet 320; a sensor outlet portion 346B, which is fluidly connected to the fluid outlet 330; and a sensor measuring portion 346C around which are placed two resistive coils or windings 346D, 346E and which is fluidly connected to the sensor inlet and sensor outlet. The mass flow meter 300 may include a pressure drop bypass (existing structures not shown) through which the remainder of the fluid contained at the fluid inlet 320 flows, for where the mass flow meter is designed for Examples of higher flow rates.

Control electronics 360 are mounted on printed circuit board 365, which may be attached to thermal mass flow sensor 346, base 310, or both. Control electronics 360 includes: some form of controller 360A (e.g., a microprocessor or digital signal processor); some memory 360B (e.g., RAM, ROM, flash memory, or a combination thereof) connected to the controller , and can store digital and/or data that can be executed and/or used by the controller; and, some electronic components 360C combined with the thermal mass flow sensor 346 . Control electronics assembly 360 can process the electronic signal provided by thermal mass flow sensor 346 representing the flow rate of fluid flowing through the thermal mass flow sensor and provide an output signal representative of the mass flow rate of fluid flowing through mass flow meter 300 .

In general, thermal mass flow sensor 346 may be enclosed within a sensor housing 348 attached to base 310 to isolate thermal mass flow sensor 346 from the surrounding environment. The sensor housing 348 may be at least partially filled with an insulating material (not shown), such as insulating foam or insulating fibers, so that the amount of convection that may occur within the sensor housing 348 is limited and thermal mass flow can be diverted. Sensor 346 is further isolated from the surrounding environment.

Where control electronics 360 and printed circuit board 365 are integrated with thermal mass flow sensor 346 to form an integral mass flow meter, a second housing (not shown) may be attached to base 310 to provide Thermal mass flow sensor 346, sensor housing 348, control electronics assembly 360, and printed circuit board 365 are enclosed for purposes such as EMI/RFI shielding, safety considerations, aesthetic considerations, and the like. Regardless of whether other parts, such as control electronics and printed circuit boards, are integrated with the thermal mass flow sensor 346, the second housing can be used to further integrate the thermal mass flow sensor 346 with any other device that may affect the operation of the mass flow meter. isolated.

Mass flow meter 300 also includes an inclination sensor 370 capable of providing a signal indicative of the inclination angle of at least one of sensor inlet portion 346A, sensor outlet portion 346B, and sensor measurement portion 346C relative to at least one reference axis. In most thermal mass flow sensors, the sensor inlet portion 346A, the sensor outlet portion 346B, and the sensor measurement portion 346C are aligned on the same plane (for example, XY plane) in the manner shown in FIG. 1 , so that the sensor inlet portion 346A and sensor outlet portion 346B are generally perpendicular to the heated (or cooled) sensor measurement portion 346C and are substantially shorter in length than the sensor measurement portion. Because the sensor measurement portion is generally the longest portion of the sensor, and its tilt angle tends to have the strongest effect on recirculation, it is preferred that the inclination sensor 370 is capable of providing a sensor measurement portion 346C relative to at least one reference axis. reading of the tilt angle. However, since the shape of the flow sensor is generally known, it should be appreciated that the inclination sensor 370 may alternately provide a reading of the inclination angle of either sensor inlet portion 346A, sensor outlet portion 346B, or both. However, if the shape of the flow sensor is known, the inclination angle of one sensor part can be used to determine the inclination angle of another sensor part.

In the embodiment shown in FIG. 1 , when the sensor measurement portion 346C is generally parallel to a length of the base 310 and the X axis, the inclination sensor 370 can indicate the angle of inclination relative to at least the X axis (this can also be stated As a result, the inclination sensor can indicate the rotation of the sensor measuring part around the Z axis). Preferably, however, in the embodiment shown in FIG. 1 , the inclination sensor is able to indicate the angle of inclination with respect to more than one axis and, preferably, is able to indicate the angle of inclination that has the greatest impact on the accuracy of mass flow meter 300 . The angle of inclination of these axes. The inclination sensor 370 can indicate the inclination angle of the sensor measurement portion 346C relative to the X and Y axes (or, alternatively, the inclination sensor can indicate the rotation of the sensor measurement portion about the Z and X axes, respectively).

While the angle of inclination of the sensor's measuring section has a significant effect on recirculation, there are other physical phenomena that may affect the accuracy of a thermal mass flow meter, and are related to sensor inlet 346A, sensor outlet 346B, and The sensor measures the inclination angle of one or more of the parts 346C. One of these phenomena, referred to herein as the external effect, points out that the manner or rate at which heat (or cooling) the sensor housing 348 dissipates to its surrounding ambient temperature may vary depending on the orientation of the mass flow meter fact. Another phenomenon, referred to herein as the density effect or the rho-g-h effect, points out the different densities of the fluids in the sensor inlet and sensor outlet portions 346A, 346B, and the difference between the sensor inlet and sensor outlet portions. The combined result of the angle of inclination may contribute to the fact that temperature induced buoyancy forces either block or assist fluid flow through the sensor. From the detected inclination angle of a part of the sensor relative to at least one reference axis, correction factors can be determined which compensate for recirculation effects, external effects, density effects or other orientation-dependent effects Error in measured flow rate. Furthermore, these correction factors can also be applied to the mass flow signal provided by the mass flow meter.

According to one embodiment, the inclination sensor is capable of providing readings of the angle of inclination of the sensor measurement portion 346C with respect to three orthogonal axes, two of which are perpendicular to the longitudinal axis of the sensor measurement portion and the remaining axis aligned therewith. The longitudinal axis of the sensor's measuring section. In the embodiment shown in FIG. 1, these three orthogonal axes correspond to X, Y and Z axes respectively, so that the inclination sensor can indicate the rotation of the sensor measuring part around the Z, X and Y axes respectively. Although the most significant effect on recirculation is related to the tilt angle of the sensor measuring portion relative to the X axis (rotation around the Z axis in Figure 1), the tilt angle relative to the Y axis (rotation around the X axis in Figure 1 The rotation of the sensor, or the orientation in which the sensor inlet is aligned with the sensor outlet), generally has a small but still measurable effect on the accuracy of the thermal mass flow meter due to the density effects described above.

According to an embodiment of the present invention, inclination sensor 370 may be any of a number of known inclination sensors, such as electromechanical inclination sensors, piezoelectric inclination sensors, liquid inclination inclination sensors, optical or magnetic Inductive tilt sensor, thermal or capacitive MEMS tilt sensor. The tilt sensor is mounted such that at least one (preferably two) of the tilt effective axes are not parallel to the sensor measurement portion 346C and, preferably, perpendicular to the longitudinal axis of the sensor measurement portion. When using an inclination sensor with three effective axes of inclination, preferably the third effective axis of inclination is parallel to the longitudinal axis of the sensor's measuring portion.

In the embodiment shown in FIG. 1 , the inclination sensor 370 is attached to the printed circuit board 365 , which in turn is attached to the base 310 . The inclination sensor 370 can also be placed at other positions, as long as the orientation of the inclination effective axis of the inclination sensor has a well-known corresponding relationship with the orientation of the thermal mass flow sensor 346 . Thus, for example, the inclination sensor 370 could be attached to the base 310 or any other part of the flow meter with a known correspondence to the orientation of the sensor so that it can be correctly identified The inclination of at least a portion of the thermal mass flow sensor relative to at least one reference axis.

Mass flow meter 300 may include more than one temperature sensor 370A, 370B, and more than one pressure sensor 375, each in communication with controller 36A. In the embodiment shown in FIG. 1, a temperature sensor 370A is placed in thermal communication with the inlet 320 of the mass flow meter, thereby providing an indication of the temperature of the process fluid flowing into the mass flow meter. Where the base 310 is made of a thermally conductive material such as stainless steel, aluminum, or brass, this temperature generally represents the temperature of the fluid passing through the mass flow meter, but does not include the fluid within the thermal mass flow sensor 346 itself. Knowledge of the temperature of the process fluid entering the mass flow meter, when combined with knowledge of the amount of heating (or cooling) provided by the resistive coils or windings 346D, 346E, provides an estimate of the density of the fluid in different parts of the mass flow meter. and/or stickiness to provide more accurate determination.

In addition to one or more temperature sensors 370A placed in thermal communication with the process fluid, mass flow meter 300 may also include a temperature sensor 370B placed within the mass flow meter but not in contact with the process fluid flowing therein. Thermal connectivity. For example, the temperature sensor 370B may also be placed on the printed circuit board 365 and proximate to the sensor housing 348, thus measuring the temperature of the environment in its vicinity. A reading of the ambient temperature around the sensor housing can be used to determine the amount of error due to external effects.

To illustrate the manner in which orientation-dependent inaccuracies are determined, and the manner in which compensation may be provided, a conventional method of compensation for use with the mass flow meter shown in FIG. 1 will therefore be described with reference to FIG. 2 .

In step 410, a controller such as controller 360A in FIG. 1 may interrogate one or more tilt sensors capable of determining the tilt angle of the thermal mass flow sensor relative to at least one reference axis. It will be appreciated that this step is preferably after the flow meter has been installed at its intended location (ie its working location). Moreover, as previously described in FIG. 1 , the at least one reference axis preferably includes at least two reference axes that are orthogonal to each other, and preferably includes at least one reference axis that is not parallel to the sensor measuring portion 346C. In the embodiment shown in FIG. 1 , these at least two reference axes identify the extent to which the sensor measurement portion is offset from the horizontal direction and the direction in which the sensor inlet and outlet portions point. When separate inclination sensors are provided to correspond to each reference axis, the controller may interrogate each inclination sensor in sequence, however, it will be appreciated that a single inclination sensor may also be used to confirm that the relative to at least one The tilt angle of the reference axis. After interrogating one or more inclination sensors, the compensation routine proceeds to step 420 .

In step 420, the compensation routine determines a combined correction factor for recirculation and external effects to compensate for any inaccuracies in the mass flow output signal due to these effects and the orientation of the sensor.

In step 430, the compensation routine determines a correction factor for density effects or rho-g-h effects to compensate for any in the mass flow output signal primarily due to the orientation of the sensor inlet and outlet portions 346A, 346B. Inaccurate based on density.

In step 440, the correction factors determined in steps 420 and 430 are applied to the output signal of the mass flowmeter such that the output mass flow signal provided by the mass flowmeter compensates for the difference due to the installation orientation of the flowmeter. resulting in any orientation-induced inaccuracies.

The step 410 of determining the inclination of the mass flow meter only needs to be performed after the flow meter is installed in its working position, or after it is installed in a new working position. For example, to ensure that the orientation of the flowmeter is compensated, the determination of the inclination of the flowmeter may be performed when the mass flowmeter is powered, after any other start-up procedures have been performed.

The above descriptions are only preferred embodiments of the present utility model, and are not intended to limit the present utility model. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present utility model shall be included in the Within the protection scope of the present utility model.

Claims (4)

1. A mass flowmeter has a fluid inlet and a fluid outlet, characterized in that it includes a thermal mass flow sensor, an inclination sensor, a controller and adjacent fluid flow paths, and the thermal mass flow sensor is used to provide a fluid inlet and a fluid outlet A first electronic signal of a mass flow rate of fluid flowing between fluid outlets, a thermal mass flow sensor having a sensor inlet portion fluidly connected to the fluid inlet, a sensor outlet portion fluidly connected to the fluid outlet, and positioned and fluidly connected to the The sensor measuring part between the sensor inlet part and the sensor outlet part; the inclination sensor is used to provide at least one second electronic signal to provide at least one of the sensor inlet part, the sensor outlet part, and the sensor measuring part relative to The inclination angle of at least one reference axis; the controller is used to receive the first electronic signal and the second electronic signal, calculate a correction factor according to the second electronic signal, and apply the correction factor to the first electronic signal to provide a third electronic signal , the third electronic signal is used to provide the mass flow rate of the fluid flowing between the fluid inlet and the fluid outlet, so as to compensate the inclination angle of at least one sensor part relative to at least one reference axis; the adjacent fluid flow path, which There is a flow path inlet positioned adjacent to the sensor inlet portion and fluidly connected to the fluid inlet, and a flow path outlet positioned adjacent to the sensor outlet portion and fluidly connected to the fluid outlet. 2. The mass flow meter of claim 1, further comprising a bypass tube disposed in an adjacent fluid flow path. 3. The mass flow meter of claim 1, wherein the third electronic signal is used to compensate for recirculation between the thermal mass flow sensor and an adjacent fluid flow channel. 4. The mass flow meter according to claim 1, wherein the second electronic signal is used to provide an inclination angle of the measuring portion of the sensor relative to at least one reference axis, and the third electronic signal is used to compensate thermal mass flow Recirculation between the sensor and adjacent fluid flow paths.