Mass flow sensor assembly and method for manufacturing a mass flow sensor assembly

Abstract

A mass flow sensor assembly (10) for a mass flow regulator or a mass flow measuring device has a mass flow sensor (22) comprising a capillary tube (28) held by a first corner carrier (24) and a second corner carrier (26), which are formed independently of one another. The capillary tube (28) comprises a sensor section (34) which is located between the two corner carriers (24, 26), and wherein the two corner carriers (24, 26) each have an arcuate slot (88, 90) in which the capillary tube (28) is partially accommodated. Furthermore, a method for manufacturing a mass flow sensor assembly (10) is described.

Description

Technical Field

[0001] This invention relates to a mass flow sensor assembly for use in a mass flow controller ("MFC") or mass flow meter ("MFM"). Furthermore, this invention relates to a method for manufacturing the mass flow sensor assembly. Background Technology

[0002] Mass flow controllers or mass flow meters are known in the prior art, and these controllers or meters typically include a mass flow sensor configured as a capillary sensor. The mass flow sensor is usually associated with a bypass line of the mass flow controller or meter. In addition to the bypass line, the mass flow controller or meter usually includes a main line, which, for example, constitutes a primary channel through which most of the medium to be measured flows. A (laminar) flow element is disposed in the primary channel, which generates a (small) pressure drop. The laminar flow element is also called a laminar element (LFE). Due to the pressure drop, a portion of the total flow rate proportional to the pressure drop is driven by the capillary of the mass flow sensor, which measures the corresponding mass flow. From this, the total mass flow rate can be deduced, provided the characteristics of the flow element are known. Alternatively, the main line can be closed as much as possible, so that an approximate total mass flow rate flows through the bypass line. The terms "bypass line" and "main line" can, in principle, be used in reverse order of understanding.

[0003] The specific measurement of mass flow is typically performed via a sensor coil, which is formed by a wound heating resistor or heating wire connected to the evaluation electronics. As the medium to be measured flows through the capillary, heat is transported along the flow direction by the flow, which is detected accordingly by the sensor coil and can then be evaluated by the evaluation electronics.

[0004] Mass flow sensor assemblies known from existing technologies are relatively complex to manufacture due to the costly operation of delicate capillaries. This complexity leads to high manufacturing costs. Summary of the Invention

[0005] The object of this invention is to provide a mass flow sensor assembly that is simple in construction and cost-effective to manufacture.

[0006] The objective according to the invention is achieved by a mass flow sensor assembly for a mass flow regulator or mass flow meter, the mass flow sensor assembly including a mass flow sensor. The mass flow sensor has a capillary tube held by a first corner support and a second corner support, the first and second corner supports being independently formed. The capillary tube includes a sensor section located between the two corner supports. Each of the two corner supports has an arcuate groove in which the capillary tube is partially accommodated.

[0007] The basic concept of this invention is to mechanically fix a capillary tube in a simple manner, namely, by having the capillary tube supported by two separately constructed corner carriers. Furthermore, the capillary tube can be pre-fixed in a desired form, as it only needs to be inserted into the two corner carriers, particularly the corresponding arcuate grooves, for secure holding. The capillary tube is manufactured as a one-piece or integral component, thereby simplifying its operability and mechanical fixation, which is particularly significant when subsequently setting up the sensor coil.

[0008] Furthermore, the capillary tube, especially its sensor section, is exposed between the two corner support members. This allows the sensor section to be more easily surrounded by thermal insulation, resulting in better thermal protection. Consequently, measurement accuracy is improved because external thermal influences are effectively shielded.

[0009] As long as the two corner bearings are not touching each other, the corner bearings will not come into contact. More precisely, the two corner bearings will be spaced apart from each other.

[0010] Because the two corner support members are spaced apart from each other, a gap or free space is provided between the two corner support members. The free space is particularly related to the sensor section.

[0011] The two corner bearings are therefore associated only with different sections of the capillary, particularly with respect to the reverse section of the sensor section of the capillary. The reverse section of the sensor section is the section connected to the corresponding end of the sensor section.

[0012] The two corner support members are specifically positioned in a common plane, particularly in the common section of the mass flow sensor assembly. The capillary also extends in this plane.

[0013] Therefore, the corner support is not two housing halves assembled to form a housing for the capillary.

[0014] In the mass flow sensor assembly, the two corner carriers are components that are independent of each other.

[0015] The mass flow sensor assembly is based on the capillary sensor's measurement principle.

[0016] One aspect proposes that the capillary has at least two arcuate segments disposed in arcuate grooves of two corner support members, wherein a sensor segment is disposed in the two arcuate segments. Straight-extending legs can be connected to the two arcuate segments respectively, particularly to the corresponding ends of the arcuate segments opposite to the sensor segments. The arcuate segments can each correspond to a (basically) 90° curve, such that the entire capillary has a (basically) U-shape.

[0017] U-shaped capillaries can be manufactured accordingly or should be modified accordingly beforehand, for example, by plastic deformation.

[0018] In particular, the corner support is associated (only) with one of the two arcuate segments of the capillary. For this reason, the corner support is also called a corner carrier, because it supports the arcuate segment of the capillary corresponding to the corner.

[0019] The corner support can therefore be configured such that it each accommodates only one arcuate segment, wherein the leg extending from the arcuate segment and the sensor segment extending from the arcuate segment are not supported by the corresponding corner support. In other words, the leg and the sensor segment are exposed with respect to the corresponding corner support.

[0020] Overall, only the two curved sections of the capillary are supported by corner brackets, while the two legs and the sensor section are exposed relative to the corner brackets. In particular, the curved sections of the capillary are supported only by corner brackets.

[0021] In principle, especially in a one-piece construction, the capillary can be made of metal, such as stainless steel. This allows corrosive media to be guided through the capillary. In particular, it lacks elastomers, such as seals or the like, which could come into contact with the media and be corroded.

[0022] To secure the capillary to the corner support, the arcuate section is additionally secured by material fit and / or force fit, for example, via adhesive bonding, after it is inserted into the corresponding arcuate groove (form fit). This ensures the capillary's durable fixation to the corner support, thereby ensuring the reliable functionality of the mass flow sensor.

[0023] On the other hand, it is proposed that the mass flow sensor has a first sensor coil and a second sensor coil, which are electrically insulated from each other and at least partially wound around a sensor segment, wherein the first sensor coil is associated with a first corner support and the second sensor coil is associated with a second corner support. The sensor coils are wound in a particularly identical manner, resulting in high measurement accuracy of the mass flow sensor because there are no manufacturing-dependent variations in the sensor coils that could affect the measurement results. The sensor coils can be wound in mirror-image configurations such that they extend in the same manner from their associated corner support toward their respective other sensor coils.

[0024] The two sensor coils can be electrically insulated from each other by wrapping the two wires with an electrical insulating layer. A gap exists between the two sensor coils in the region of the sensor section of the capillary. In other words, this means that the windings of the two sensor coils do not overlap.

[0025] In principle, the sensor coil can be constructed using wires wound around a capillary tube, thus comprising multiple windings. The wires can be heating wires or wires used as heating resistors.

[0026] The sensor coil can also be fixed to the capillary and / or corresponding corner support in a material-fit and / or force-fit manner, especially bonded to the capillary or corner support. This ensures that the corresponding sensor coil cannot slip off. A form-fit connection has already been established via the winding, to which a material-fit or force-fit connection can be additionally provided.

[0027] Specifically, the respective sensor coils, namely the first sensor coil and the second sensor coil, have a first end and a second end, which are connected to a first contact element or a second contact element of the associated corner carrier. In other words, the first end of the respective sensor coil is connected to the first contact element (electrically and / or mechanically) of the respective corner carrier. The second end of the respective sensor coil is connected to the second contact element (electrically and / or mechanically) of the respective corner carrier. The two sensor coils thus each have two ends, which are connected to the associated contact element of the respective corner carrier. The two ends are therefore free ends of the respective wires, which are wound around a capillary tube to form the respective sensor coil. The connection between the ends and the respective contact elements can be established via welding, bonding, and / or adhesive bonding.

[0028] In principle, the corner brackets, in addition to mechanically securing the capillary tube, also serve to electrically contact the corresponding sensor coil. This further enables a more precise configuration of the sensor coil, i.e., a more precise winding. The corresponding ends can be mechanically fixed to the corner brackets, effectively preventing the sensor coil from slipping off.

[0029] On the other hand, it is proposed that the corresponding sensor coil has at least one winding that is wound around a fixed protrusion of an associated corner support. The protrusion may be part of a first contact element, thereby enabling electrical contact. It is also possible to propose that the corresponding sensor coil is wound around the fixed protrusion with at least one winding to fix the sensor coil in its position. In either case, this simplifies the electrical contact and mechanical fixation of the corresponding sensor coil.

[0030] In particular, the fixing protrusion is oriented substantially perpendicular to the sensor section. This improves the mechanical fixation of the sensor coil relative to the capillary.

[0031] In principle, the fixed protrusion can also be called the corner bearing nose, because the fixed protrusion extends outward from the base of the corner bearing in a nose-like shape.

[0032] On the other hand, it is proposed that the mass flow sensor assembly has a sensor housing in which the mass flow sensor is partially housed, and particularly wherein the sensor housing is constructed in multiple parts. The sensor housing protects the mass flow sensor from external influences.

[0033] In particular, the sensor housing also provides thermal insulation, which improves the measurement accuracy of the mass flow sensor. In other words, the mass flow sensor, especially the capillary, is better thermally shielded.

[0034] For example, the sensor housing includes a base and a cover, which together define a receiving space for a mass flow sensor. The mass flow sensor can be inserted into the base, wherein the cover is largely closed outward to protect the mass flow sensor. Castable refractory can be additionally introduced into the receiving space.

[0035] In this regard, the sensor housing can be constructed in two pieces or composed of two separate parts.

[0036] One approach proposes a sensor housing comprising two open sections and a cavity, wherein two corner support members are accommodated in the open sections, and the cavity is located between the two open sections, through which a capillary sensor section extends, and in particular, at least one insulating portion is disposed within the cavity. Improved thermal insulation of the mass flow sensor is ensured via the cavity, which is associated with the capillary sensor section. Through this additional thermal insulation, the capillary, and particularly the sensor section, is further shielded from external or environmental influences.

[0037] Furthermore, the mass flow sensor assembly may have a printed circuit board that is electrically contacted with the mass flow sensor via at least one electrical contact. The printed circuit board particularly has multiple electrical contacts that are respectively electrically contacted with contact elements formed on the corner carrier.

[0038] In this regard, corner carriers have other functions, enabling direct electrical contact with printed circuit boards without the need for additional components.

[0039] In principle, the corner carrier therefore has different functions: mechanically fixing the capillary, electrically contacting the sensor coil, and making direct electrical contact with the printed circuit board. In other words, the corner carrier has multiple electrical interfaces and mechanical interfaces to provide the above functions.

[0040] In principle, the present invention further includes a mass flow controller (MFC) or mass flow meter (MFM) having a mass flow sensor assembly of the type described above. The mass flow controller or meter, in addition to the mass flow sensor, has a fluid block and optionally a valve. Furthermore, the mass flow controller or meter may also have a housing, as long as this is not constructed through a sensor housing. A printed circuit board including evaluation electronics can also provide electronics for the mass flow controller or meter, as long as it does not have its own electronics.

[0041] The fluid block may have: at least one main pipeline having a flow element or flow resistance element disposed therein; and an interface for a mass flow sensor assembly, which constitutes a bypass pipeline. In particular, a capillary tube constitutes a bypass pipeline for a mass flow controller (MFC) or mass flow meter (MFM).

[0042] Furthermore, the objective is achieved according to the present invention by a method for manufacturing a mass flow sensor assembly, comprising the following steps:

[0043] - Provides a first corner support and a second corner support, the first corner support and the second corner support each having an arcuate groove and being spaced apart from each other, and

[0044] - The capillary tube is inserted into the corner support by placing the arc-shaped section of the capillary tube into the arc-shaped groove, so that the sensor section of the capillary tube is formed between two spaced corner support members.

[0045] This results in a mass flow sensor assembly that ensures the capillary sensor section can be particularly well shielded because it is located between two spaced-apart corner carriers. In other words, the sensor section is exposed (initially) between the two corner carriers, allowing the thermal insulation to be positioned very close to the sensor section. This leads to improved measurement accuracy of the mass flow sensor assembly.

[0046] Because the two corner support members are spaced apart from each other, there is a gap or free space between the two corner support members. The free space is particularly related to the sensor section.

[0047] Furthermore, the mass flow sensor assembly is made easier to manufacture because the capillary is prefabricated in a desired manner and can then be easily coupled to the two corner carriers by inserting the pre-formed capillary into the arcuate grooves of the corner carriers.

[0048] Furthermore, capillary tubes can be constructed as a single piece, rather than consisting of multiple separately constructed components connected to each other via seals or the like. This also enables the use of mass flow sensor assemblies in processes involving corrosive media.

[0049] One approach proposes manufacturing two corner carriers within a common nutzen. The nutzen is a main circuit board, as commonly referred to in electrical interconnect technology, composed of individual circuit boards that are not yet segmented. In this regard, the nutzen has multiple corner carriers arranged side-by-side or overlapping. The corner carriers can be formed by milling or etching.

[0050] In connecting plates, the corner carriers are arranged substantially in pairs, mirror-symmetrically to each other, i.e., mirror-symmetrical about an axis of symmetry. These corner carriers can be two corner carriers for a mass flow sensor assembly, particularly for the mass flow sensor itself.

[0051] Furthermore, the connecting plate may have multiple separating edges, through which the corresponding corner support can be easily separated, for example, by manually breaking the corner support at the separating edge to separate it from the rest. Alternatively or additionally, the corner support can be freely milled or punched. Apart from the separating edges, the corner support typically does not have a connection to the connecting plate.

[0052] In principle, since the connecting plate includes at least two corner support components of the mass flow sensor, the level of automation can be increased when manufacturing the mass flow sensor assembly, thereby reducing the overall manufacturing cost.

[0053] On the other hand, it is proposed that a first sensor coil and a second sensor coil are wound around a sensor segment, and the first and second sensor coils are associated with a first corner carrier or a second corner carrier. The sensor coils can be manufactured from wire, which is wound around a capillary in the region of the sensor segment, such that the wire constitutes the respective sensor coil. The two sensor coils can be wound substantially identically, thereby achieving a correspondingly high measurement accuracy of the manufactured mass flow sensor assembly.

[0054] First, the first end of the wire can be temporarily secured to an associated corner element, whereby the remainder of the wire is subsequently wound around a capillary to form a corresponding sensor coil. Then, the other end of the wire, the second end, is secured (temporarily) and, more permanently, by means of a corner carrier. Alternatively, the second end of the wire can be permanently secured directly. The first end of the wire can then be permanently secured as long as it has not yet been started.

[0055] Temporary fixation at the ends can be achieved via adhesive tape, which is then removed after the ends have been permanently secured and / or electrically contacted. Alternatively, temporary fixation can be omitted, leaving the ends directly and permanently fixed.

[0056] The two ends of the respective sensor coils can be electrically and / or mechanically connected to the first contact element and the second contact element of the respective corner carrier, for example by means of welding. By welding, the (previously applied) electrical insulation layer of the two sensor coils is removed. This ensures that the sensor coils are electrically contacted and simultaneously achieve the desired position.

[0057] The sensor coils thus make electrical contact with the contact elements of the associated corner carriers via their ends.

[0058] It can be proposed that at least one winding of each sensor coil is wound around a fixed protrusion of the associated corner carrier in order to mechanically fix the corresponding sensor coil to the corner carrier.

[0059] The above steps are performed on both sensor coils. This can be done simultaneously or sequentially.

[0060] Furthermore, it can be suggested that the corresponding sensor coils are also fixed to the capillary in a material-fitting and / or force-fitting manner to prevent subsequent movement of the individual windings. For example, an adhesive connection may be provided.

[0061] Therefore, mass flow sensors can be manufactured and constructed.

[0062] A sensor housing is provided for this purpose, which is constructed, for example, in a multi-part configuration. For instance, the sensor housing includes a base component and a cover component.

[0063] Firstly, the sleeve can be pressed into the sensor housing, especially the base component, and / or the insulating part can be placed in the cavity of the sensor housing. Alternatively, the sleeve can be glued to the sensor housing and / or welded to the sensor housing.

[0064] The mass flow sensor is inserted as follows: the legs of the U-shaped capillary are introduced into the corresponding sleeve, positioning the mass flow sensor and orienting it relative to the sensor housing. The sensor section of the capillary is then positioned in the cavity region of the sensor housing, which is partially closed outward from one side by an insulating portion. The legs of the U-shaped capillary can extend noticeably and at an undefined distance after being introduced into the corresponding sleeve.

[0065] Subsequently, a second insulating part can be inserted into the cavity, so that the sensor section of the capillary can be thermally surrounded or encapsulated by the insulating part.

[0066] The sensor housing can then be sealed. This can be achieved by attaching a cover to the base component of the sensor housing, thus protecting the mass flow sensor from external environmental influences. Both the cover and the base component share a receiving space in which the mass flow sensor is housed.

[0067] The second insulating part can also be placed in the cover, so that when the cover is placed on the base, the second insulating part thermally encapsulates the sensor section together with the first insulating part.

[0068] Subsequently, the mass flow sensor can be permanently connected, for example by coupling the capillary to at least one of the sleeves, particularly by welding.

[0069] To address this, the capillary tube is first moved back into the sleeve by a punch until it protrudes slightly from the sleeve, for example, by a predetermined distance.

[0070] Subsequently, the end of the capillary can be modified using a punch, especially by curling the edges.

[0071] After that, the sleeve can be pressed together with the capillary tube using a punch.

[0072] Subsequently, the capillary can be welded to the sleeve. Here, a laser can be provided that performs a (oscillating) rotational motion to effectively weld the modified end of the capillary to the sleeve.

[0073] The space containing the mass flow sensor is then filled with a casting material, such as casting resin, so that the mass flow sensor is embedded in the casting material and thus protected within the sensor housing.

[0074] Finally, the printed circuit board (PCB) can be coupled to the sensor housing, and the PCB can simultaneously make electrical contact with the corner carrier. The PCB has corresponding electrical contacts for this purpose. These electrical contacts can be permanently connected to the corner carrier separately, for example, by soldering. This ensures both mechanical and electrical connections between the PCB and the corresponding corner carrier, i.e., the mass flow sensor.

[0075] The filling space can be filled with castable material, or it can be done after the mechanical and electrical connections are established. Attached Figure Description

[0076] Other advantages and features of the invention will become apparent from the following description and the accompanying drawings. The drawings show:

[0077] - Figure 1 An exploded view of the mass flow sensor assembly according to the present invention is shown.

[0078] - Figure 2 Show Figure 1 A perspective view of the mass flow sensor assembly according to the present invention.

[0079] - Figure 3 Show Figure 1 and 2 A cross-sectional view of the mass flow sensor assembly.

[0080] - Figure 4 A top view is shown of the connecting plate for manufacturing the corner support member of the mass flow sensor assembly according to the present invention.

[0081] - Figure 5 Show Figure 4 Detailed images showing two corner support members.

[0082] - Figure 6 This is shown in the subsequent manufacturing steps. Figure 5 Corner bearings,

[0083] - Figure 7 Show Figure 6 A view rotated 180°.

[0084] - Figure 8 Show Figure 6 and 7 A three-dimensional view showing details of the subsequent manufacturing steps.

[0085] - Figure 9 Show Figure 8 Details

[0086] - Figure 10 A perspective view of the mass flow sensor assembly to be manufactured at a subsequent moment in the manufacturing process is shown.

[0087] - Figure 11 The basis shown at the subsequent moment Figure 2 A 3D view of the mass flow sensor assembly manufactured.

[0088] - Figure 12 Showing according to Figure 11 A cross-sectional view of the manufactured mass flow sensor assembly, and

[0089] - Figure 13 Show Figure 12 Detailed images. Detailed Implementation

[0090] exist Figure 1 An exploded view of a mass flow sensor assembly 10 is shown, which is used in a mass flow controller (MFC) or mass flow meter (MFM).

[0091] In the illustrated embodiment, the mass flow sensor assembly 10 includes a sensor housing 12, which is currently constructed in two parts and includes a base component 14 and a cover component 16, which may also be referred to as a housing cover.

[0092] Furthermore, the mass flow sensor assembly 10 includes a printed circuit board 18, which, in its assembled state, is coupled to the sensor housing 12, as from... Figure 2 The conclusion drawn from this is that... Figure 2 The image shows the mass flow sensor assembly 10 in an assembled state.

[0093] The printed circuit board 18 can be at least partially inserted into or mounted on the sensor housing 12, and can be mechanically and releasably fixed to the sensor housing 12 via a fixing mechanism 20, such as screws. Figure 2 As clearly seen in the text.

[0094] Furthermore, the mass flow sensor assembly 10 includes a mass flow sensor 22, which, in its assembled state, is at least partially, and especially as far as possible, housed within the sensor housing 12, such as from... Figure 2 As clearly seen in the text.

[0095] The mass flow sensor 22 includes two corner support members 24, 26 and a capillary tube 28, which is supported or held by the two corner support members 24, 26.

[0096] Capillary 28 includes a first leg 30, an arcuate section 32 connected thereto, a sensor section 34 connected thereto, an arcuate section 36 connected thereto, and a second leg 38, the second leg extending from the second arcuate section 36, such as from... Figure 3 As can be clearly seen in the middle, Figure 3 This shows a view rotated 180°.

[0097] The two arc-shaped segments 32 and 36 basically correspond to a 90° curve, making the capillary 28 U-shaped overall, wherein the two free ends of the capillary 28 are associated with the legs 30 and 38.

[0098] Furthermore, the mass flow sensor 22 includes a first sensor coil 40 and a second sensor coil 42, which are wound around the sensor section 34 of the capillary 28. The two sensor coils 40 and 42 are electrically insulated from each other. In addition, a gap 44 is provided between the two sensor coils 40 and 42. In other words, the windings of the sensor coils 40 and 42 do not overlap in the region of the gap 44.

[0099] Sensor coils 40 and 42 are associated with one of the two corner carriers 24 and 26, respectively.

[0100] The two sensor coils 40 and 42 are each made of wire, which is wound around the capillary 28 in the region of the sensor section 34. The respective wires therefore have two open ends, which must be electrically contacted.

[0101] In particular, each of the two sensor coils 40, 42 is electrically connected to the corner carriers 24, 26 via its two ends.

[0102] The corresponding corner carriers 24, 26 have first contact elements 46, 48 or second contact elements 50, 52 on which the two ends of the sensor coils 40, 42 are mechanically and electrically connected, for example, via welding.

[0103] In the illustrated embodiment, the first contact elements 46 and 48 of the two corner carriers 24 and 26 are associated with the fixing protrusions 54 and 56 of the corner carriers 24 and 26, respectively.

[0104] Specifically, sensor coils 40 and 42 are wound with at least one winding around the corresponding fixed protrusions 54 and 56 of the corresponding corner bearings 24 and 26, respectively, so that the mechanical fixation of sensor coils 40 and 42 about capillary tube 28 is feasible.

[0105] The first contact elements 46, 48 extend from the fixed protrusions 54, 56 to the distal ends of the corresponding corner bearings 24, 26, and the second contact elements 50, 52 also extend toward there.

[0106] The distal ends of the corresponding corner support members 24, 26 extend from the sensor housing 12 such that if the mass flow sensor 22 is housed within the sensor housing 12, the distal ends are contacted by the printed circuit board 18, as from... Figure 2As clearly seen in the text.

[0107] The printed circuit board 18 has first electrical contacts 58, 60 and second electrical contacts 62, 64, which work together with the corresponding first contact elements 46, 48 and second contact elements 50, 52 of the corner carriers 24, 26 to ensure electrical contact between the mass flow sensor 22 and the printed circuit board 18.

[0108] Electrical connections can also be established via welding, which also enables mechanical fixation.

[0109] from Figure 1 It is also clear that the mass flow sensor 22 can be housed in the sensor housing 12, especially in the base 14, because there are openings 66, 68 for this purpose, in which the two corner support members 24, 26 of the mass flow sensor 22 can be accommodated.

[0110] The openings 66 and 68 are associated with the openings 70 and 72 of the sensor housing 12, particularly the basic component 14, into which sleeves 74 and 76 are inserted, as also referred to below. Figures 4 to 13 As explained.

[0111] A cavity 78 is provided between the two empty portions 66 and 68. When the mass flow sensor 22 is inserted into the sensor housing 12, the cavity is associated with the sensor section 34 of the capillary 28.

[0112] In addition, two insulating parts 80 and 82 are provided in the cavity 78 in the assembled state, which thermally insulate the mass flow sensor 22 and, in particular, thermally encapsulate the sensor section 34 of the capillary 28.

[0113] After the mass flow sensor 22 is inserted into the sensor housing 12, the cover 16 is connected to the base 14 via the fixing mechanism 84, so that the mass flow sensor 22 is housed in the sensor housing 12 against external influences.

[0114] The intermediate space between the cover 16 and the base 12, which accommodates the mass flow sensor 22, is completely filled, for example, by the casting material 86, so that the mass flow sensor 22 is protected and accommodated in the sensor housing 12. The fillable intermediate space includes, for example, empty portions 66, 68 and vacates a cavity 78 with insulating portions 80, 82 in which the mass flow sensor 22 is located.

[0115] From the shown Figure 2 cross-sectional view Figure 3Furthermore, it is found that the free end of the U-shaped capillary 28, namely the end of the capillary 28 associated with the legs 30, 38, is associated with two sleeves 74, 76, which are inserted into the openings 70, 72.

[0116] In addition, from Figure 3 It is found that the two corner bearings 24 and 26 have arc-shaped grooves 88 and 90 respectively, and the capillary 28 is accommodated in the arc-shaped grooves via its two arc-shaped sections 32 and 36.

[0117] The arc grooves 88 and 90 therefore also have a bend of about 90° in order to guide the capillary 28 accordingly.

[0118] The two corner bearings 24 and 26, especially the arcuate grooves 88 and 90 of the corner bearings 24 and 26, are therefore associated with only one of the two arcuate segments 32 and 36 of the capillary 28, respectively.

[0119] In other words, the two corner support members 24 and 26 are associated with different sections of the capillary 28, specifically with the two arcuate sections 32 and 36 of the capillary 28. Here, the following section of the capillary 28 is connected to the corresponding end of the sensor section 34.

[0120] The two corner bearings 24 and 26 are therefore not in contact with each other. More precisely, the two corner bearings 24 and 26 are spaced apart from each other.

[0121] In addition, from Figure 3 It is clear that the two corner bearings 24, 26 and the capillary 28 are in a common plane, especially in a common section of the mass flow sensor assembly 10.

[0122] In addition, from Figure 3 It is found that the two contact elements 46-52 of the corner bearings 24 and 26 extend to the distal end, which is opposite to the free end of the capillary 28.

[0123] The following is for reference. Figures 4 to 13 Explain how to manufacture in Figures 1 to 3 The mass flow sensor assembly 10 is shown in the figure.

[0124] In the first step, provide in Figure 4 The connecting plate 92 shown in the figure includes a plurality of corner support members 24, 26, which are arranged in substantially pairs and mirror each other around the axis of symmetry S.

[0125] exist Figure 4In the embodiment shown, a total of ten pairs of corner carriers 24, 26 are shown, each pair including a first corner carrier 24 and a second corner carrier 26, which are always used for a mass flow sensor assembly 10.

[0126] The two corner bearings 24 and 26 are oriented toward each other in the connecting plate 92 such that their arcuate grooves 88 and 90 point toward each other by means of their respective ends, see in particular Figure 5 The orientation already corresponds to the orientation in the completed manufacturing state of the mass flow sensor assembly 10, and especially the mass flow sensor 22.

[0127] In other words, the two corner support members 24 and 26 have been correctly oriented toward each other on the connecting plate 92, thereby increasing the degree of automation and reducing manufacturing costs.

[0128] In principle, the connecting plate 92 has multiple corner support members 24, 26, which are arranged side by side or stacked. The corresponding corner support members 24, 26 can be manufactured by milling or etching.

[0129] Furthermore, the connecting plate 92 includes a separating edge 94, which ensures that the corner support members 24, 26 can be easily separated from the connecting plate 92. This can be done by manual breaking, free milling, or punching.

[0130] Apart from the separating edge 94, the corresponding corner bearings 24 and 26 do not have a connection with the connecting plate 92.

[0131] Subsequently, capillary tubes 28, which have been U-shaped, are inserted into a pair of corner support members 24 and 26, i.e., into two corner support members 24 and 26 arranged in a mirror image. The arcuate segments 32 and 36 of the capillary tubes 28 are inserted into the arcuate grooves 88 and 90 of the corner support members 24 and 26, as shown in... Figure 6 As shown in the diagram.

[0132] Subsequently, the capillary 28 can be permanently connected to the two corner support members 24, 26, for example, via an adhesive portion 96, which is also provided in the respective corner support members 24, 26, particularly as a recess. The adhesive portion 96 can be created by milling or etching.

[0133] In this regard, the capillary 28 can be permanently mechanically connected to the corresponding corner bearings 24, 26 via the adhesive point at the bonding site 96.

[0134] exist Figure 6 The image shows the bonding point used only for the first corner support 24, making the recess in the second corner support 26 also visible.

[0135] After the capillary tube 28 is coupled to the two corner bearings 24 and 26, the two corner bearings 24 and 26 can be separated from the connecting plate 92 via the separating edge 94. Figure 6 As already shown in the image.

[0136] This results in two separate corner support members 24 and 26, which are connected to each other only via capillary tubes 28.

[0137] exist Figure 7 The text shows about Figure 6 The mass flow sensor 22 is rotated 180° to the corresponding intermediate state, making the corresponding contact elements 46-52 visible.

[0138] In other words, the contact elements 46-52 are located on the side of the corner carriers 24, 26 opposite to the arcuate grooves 88, 90. In an alternative embodiment, the contact elements 46-52 may also be located on the same side of the respective arcuate grooves 88, 90 or within the corner carriers 24, 26.

[0139] from Figure 7 It is clear that the corresponding first contact elements 46, 48 extend from the corresponding fixed protrusions 54, 56 to the distal ends of the corner bearings 24, 26, in particular in a U-shape, which protrudes from the sensor housing 12.

[0140] After the two corner support members 24 and 26, along with the inserted capillary tube 28, separate from the connecting plate 92, the first wire and the second wire are wound around the capillary tube 28 in the region of the sensor section 34 to form the first sensor coil 40 and the second sensor coil 42. Figure 8 It is illustrated in the diagram.

[0141] In this regard, the corresponding lines are (temporarily) connected to the associated corner bearings 24, 26 via the free ends of the lines.

[0142] The remainder of the wire is then wound around the capillary 28, especially the sensor section 34, until the corresponding sensor coils 40, 42 are wound in the desired manner.

[0143] The other free end of the wire is then connected to one of the two contact elements 46-52 of the corresponding corner carriers 24, 26, for example, via welding. In particular, the free end of the wire is also connected to the corresponding second contact elements 50, 52 of the corresponding corner carriers 24, 26.

[0144] Subsequently, the first line end that was previously only temporarily coupled to the corner carriers 24, 26 can also be permanently connected to the corner carriers, for example, by welding.

[0145] However, it can also be proposed that the first line end has already begun to be permanently connected to the corner carriers 24, 26, and especially the corresponding contact elements 46-52, preferably to the first contact elements 46, 48.

[0146] The two wires that make up the two sensor coils 40 and 42 can be wound around the capillary 28 in the region of the sensor section 34 simultaneously or sequentially.

[0147] Ultimately, the two sensor coils 40 and 42 are constructed in the same manner, wherein the two sensor coils 40 and 42 are insulated from each other because the windings of the wires of the two sensor coils do not overlap. In other words, a gap 44 is established between the two sensor coils 40 and 42 when they are wound.

[0148] After the two sensor coils 40, 42 are wound, the associated wires are coupled to the capillary 28 in a material-compatible and / or force-compatible manner to prevent subsequent slippage of the respective sensor coils 40, 42.

[0149] In a simple way, this can be ensured via adhesive bonding.

[0150] from Figure 8 and 9 Furthermore, it is found that the corresponding sensor coils 40, 42 are wound around the associated fixing protrusions 54, 56 of the corresponding corner bearings 24, 26 by means of at least one winding. In this way, the mechanical fixation of the corresponding sensor coils 40, 42 can also be achieved.

[0151] As already described, the corresponding fixing protrusions 54, 56 are part of the first contact elements 46, 48 of the corresponding corner bearings 24, 26, as also from... Figure 7 This means that, in addition to mechanical fixation, electrical contact of the sensor coils 40 and 42 can also be achieved via the fixed protrusions 54 and 56.

[0152] Mass flow sensor 22 is now manufactured and can be inserted into sensor housing 12, as from Figure 10 This is derived from...

[0153] To do this, first insert the two sleeves 74 and 76 into, for example, the openings 70 and 72, or holes.

[0154] The base component 14 of the sensor housing 12 can be formed of aluminum, which improves thermal conductivity. Alternatively, the base component 14 can be made of copper or other thermally conductive materials.

[0155] Subsequently, the first insulating part 80 is inserted into the cavity 78.

[0156] Next, the mass flow sensor 22 is inserted into the sensor housing 12, particularly the base component 14, by inserting the two corner support members 24 and 26 into the associated recesses 66 and 68. Here, the capillary tube 28 is inserted into the sleeves 74 and 76 via its ends. The sensor section 34 of the capillary tube 28 extends through the cavity 78, which is covered on one side by the first insulating portion 80.

[0157] Subsequently, a second insulating portion 82 is inserted to thermally insulate or heat-encapsulate the capillary 28, particularly the sensor section 34. This effectively shields the mass flow sensor 22 from environmental influences.

[0158] Subsequently, the cover 16 is placed and connected to the base 14 via the fixing mechanism 84.

[0159] Alternatively, the second insulating part 82 can be inserted into the cover 16 first, such that if the cover 16 is placed, the second insulating part 82 surrounds the capillary 28, especially the sensor section 34.

[0160] After the mass flow sensor 22 is inserted into the sensor housing 12, the capillary tube 28 is also coupled to the sleeves 74 and 76 in a tensile-resistant manner.

[0161] To address this, a punch 98 is used to move the capillary 28 back into the corresponding sleeves 74 and 76 until the capillary 28 protrudes only slightly from the sleeves 74 and 76. This is in Figures 11 to 13 As shown in the image.

[0162] After the printed circuit board 18 is coupled to the sensor housing 12, punch 98 is used here. This, however, can also be done beforehand, as described below.

[0163] The end of the capillary tube 28 is modified by means of the punch 98, especially the edge is rolled.

[0164] Subsequently, the corresponding sleeves 74, 76 are pressed together with the corresponding ends of the capillary 28, wherein the capillary 28 is then welded to the corresponding sleeves 74, 76 via its ends. For this purpose, a laser can be used to perform the (oscillating) rotational motion.

[0165] After the capillary 28 is permanently coupled to the sleeves 74 and 76, the mass flow sensor 22 housed in the housing 12 is cast with the casting material 86, so that the mass flow sensor 22 is housed in the sensor housing 12 against external influences.

[0166] Subsequently, the printed circuit board 18 is first fixed to the sensor housing 12, especially via the fixing mechanism 20.

[0167] The distal ends of the corresponding corner support members 24, 26 extending from the sensor housing 12 can then be mechanically and electrically coupled to the electrical contacts 58-64 of the printed circuit board 18, for example, via soldering.

[0168] The mass flow sensor assembly 10 is thus made.

Claims

1. A mass flow sensor assembly for a mass flow controller or mass flow meter, comprising a mass flow sensor including a capillary tube held by a first corner support and a second corner support, the first corner support and the second corner support being separately configured with respect to each other, wherein the capillary tube includes a sensor section located between the two corner supports, and wherein each of the two corner supports has an arcuate groove, the capillary tube being partially accommodated in the arcuate groove, wherein the two corner supports are spaced apart such that a free space is provided between the two corner supports, the sensor section being located in the free space, wherein the capillary tube has at least two arcuate sections disposed in the arcuate grooves of the two corner supports, wherein the sensor section is disposed between the two arcuate sections, and wherein the capillary tube Each arcuate segment contacts the arcuate groove of a corresponding corner carrier of the two corner carriers and is permanently connected to the corresponding corner carrier of the two corner carriers at the adhesive point, wherein the two corner carriers are separately constructed components arranged in a common plane in which the capillary extends, and wherein the two corner carriers are associated only with different segments of the capillary that are opposite to the sensor segment of the capillary, wherein the mass flow sensor assembly has a sensor housing in which the mass flow sensor is at least partially housed, and wherein the sensor housing includes two open portions and a cavity between the two open portions, wherein two corner carriers are housed in the open portions, and wherein the sensor segment of the capillary extends through the cavity.

2. The mass flow sensor assembly according to claim 1, Its features are, The mass flow sensor has a first sensor coil and a second sensor coil, which are electrically insulated from each other and wound at least partially around the sensor segment, wherein the first sensor coil is associated with the first corner support and the second sensor coil is associated with the second corner support.

3. The mass flow sensor assembly according to claim 2, Its features are, The corresponding sensor coil has a first end and a second end, which are connected to a first contact element and a second contact element of an associated corner carrier.

4. The mass flow sensor assembly according to claim 2 or 3, Its features are, The corresponding sensor coil has at least one winding that is wound around a fixed protrusion of the associated corner carrier.

5. The mass flow sensor assembly according to claim 4, Its features are, The fixed protrusion is perpendicular to the orientation of the sensor section.

6. The mass flow sensor assembly according to claim 3, Its features are, The corresponding sensor coil has at least one winding that is wound around a fixed protrusion of an associated corner carrier, wherein the fixed protrusion is part of the first contact element.

7. The mass flow sensor assembly according to claim 1, Its features are, The sensor housing is composed of multiple parts.

8. The mass flow sensor assembly according to claim 1, Its features are, At least one insulating part is disposed in the cavity.

9. A method for manufacturing a mass flow sensor assembly, the method comprising the following steps: - A sensor housing, a first corner support, and a second corner support are provided. The sensor housing has two open portions and a cavity between the two open portions. The corner support members each have arc-shaped grooves that are spaced apart from each other, creating a free space between the two corner support members. The two corner support members are independently constructed components arranged in a common plane. - Insert the corner support into the open portion of the sensor housing, and - The capillary is inserted into the corner carrier in such a way that the arcuate section of the capillary is placed into the arcuate groove, such that the sensor section of the capillary is formed between two spaced-apart corner carriers and located in the free space between the two corner carriers and in the cavity of the sensor housing, and such that each arcuate section of the capillary contacts the arcuate groove of the corresponding corner carrier of the two corner carriers, and is permanently connected to the corresponding corner carrier of the two corner carriers at the adhesive point, wherein the capillary extends in the common plane, the two corner carriers are arranged in the common plane, and wherein the two corner carriers are associated only with different sections of the capillary, the different sections being opposite in direction with respect to the sensor section of the capillary.

10. The method according to claim 9, Its features are, In addition, two corner bearings are manufactured in the common connecting plate.

11. The method according to claim 9 or 10, Its features are, A first sensor coil and a second sensor coil are wound around the sensor segment, and the first sensor coil and the second sensor coil are respectively associated with the first corner support and the second corner support.

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