DE102011101257B4 - Flow meter and method of making a flow meter - Google Patents

Abstract

The invention relates to a flow meter (1) for determining the flow rate of a flowing medium with at least one first housing (2) in which an ultrasonic measuring section (3) is provided, along which a transit time measurement by means of at least one ultrasonic transducer (4) for transmitting or receiving ultrasonic signals can be carried out, a second housing (5) which contains an arithmetic unit (6) with electronic components by means of which signal processing and / or signal evaluation can be carried out, the ultrasonic transducer (4) is located in the area of the first housing (2), the second housing (5) is at least partially filled overhead with potting compound (7) and the potting compound (7) of the second housing (5) seals the ultrasonic transducer (4) located in the area of the first housing (2) to the outside. The invention also relates to a method for producing such a flow meter.

Description

The invention relates to a flowmeter for determining the flow rate of a flowing medium. Moreover, the invention relates to a method for producing a flow meter for determining the flow rate of a flowing medium.

Known flowmeters include in a housing an ultrasonic measuring section, in which a transit time measurement by means of at least one, in particular by means of at least two ultrasonic transducers can be performed, which emit and / or receive ultrasonic signals. By determining the differential transit time of the ultrasonic signals in and against the flow direction of the medium, the flow rate is determined. For this purpose, the flowmeter includes in a housing an arithmetic unit with electronic components, by means of which a signal processing and / or signal evaluation is feasible. On a display or a display unit, the measured flow rate can be read.

Out EP 2 037 231 A1 an ultrasonic measuring device is known in which two ultrasonic transducers are arranged outside of a housing, within which the measuring section is located. The two ultrasonic transducers penetrate the wall of the housing on which they are arranged.

The DE 10 2010 020 338 A1 describes a housing assembly for an ultrasonic flowmeter, in which a housing insert is provided, which is inserted into a corresponding recess in the measuring tube insert using a sealing ring. In this case, the ultrasonic transducers are used and back shed.

In the from the DE 10 2007 011 546 A1 known fluid meter is the measuring tube housing by means of a C-shaped bracket attached to a transmitter containing the transmitter and sealed by potting housing. In this case, the ultrasonic transducers are arranged on the side facing away from the molded housing of the measuring tube housing and sealed by the headband.

The object of the present invention is to provide a flow meter in which the ultrasonic transducers are protected from moisture entering from the outside in a cost-effective manner.

This object is achieved by the entire teaching of claim 1. Advantageous developments of the flow meter will become apparent from the claims 2-12. An inventive method for producing a corresponding flow meter is taught in the claims 13 and 14.

The flowmeter according to the invention for determining the flow rate of a flowing medium comprises at least a first housing in which an ultrasonic measuring section is provided, along which a transit time measurement by means of at least one ultrasonic transducer for emitting or receiving ultrasonic signals is feasible, and a second housing, which has an arithmetic unit includes electronic and / or electrical components, by means of which signal processing and / or signal evaluation is feasible, wherein the ultrasonic transducer is in the region of the first housing, the second housing is at least partially filled with potting compound over the top and the potting compound of the second housing in the area the first housing seals ultrasonic transducer to the outside. Due to the overhead casting, the ultrasonic transducer is advantageously simultaneously sealed together with the calculating unit or the electronics. Additional sealing elements, which would make the flowmeter and its installation more expensive, are not required. The second housing can therefore be formed in one piece. It also serves as a collecting reservoir for the potting compound. In addition, the opening of the second housing located on the side facing the first housing is expediently dimensioned such that the arithmetic unit can be inserted through the opening into the second housing. The overhead casting also has the advantage that in the region of the ultrasonic transducer which is located in the first Housing is located, air or gas can be included. As a result, a contact between the ultrasonic transducer and potting compound is avoided, otherwise disturbances may occur due to a damping of the ultrasonic transducer.

The potting compound may be at least partially open in the region of the opening. Advantageously, the potting compound is just open in the region of the opening. At the same time, the potting compound thus forms a boundary of the overhead metered flow meter to the outside. When casting the first housing with the second housing partially inserted therein, this also has the advantage that the flow level and the level of the potting compound is clearly visible and also no unwanted gas inclusion occurs in areas outside the ultrasonic transducer.

Advantageously, air or gas can be enclosed by the potting compound in the region of the ultrasonic transducer. As already mentioned above, a contact between the ultrasonic transducer and potting compound can be avoided in order to avoid disturbances of the ultrasonic transducer.

The arithmetic unit may have a preferably planar board, wherein at least one, preferably a plurality of passage openings are provided in the board and / or between the board and the second housing. The flat board simultaneously forms on the back a contact surface for the first housing. Through the passage openings, which are provided in the board, and / or the marginal distance between the board and the second housing, the cast-in from one side potting compound can rise up to the other side or back of the board and connect there with the first housing or Seal the ultrasonic transducer arranged therein. In addition, several passages allow a rapid and at the same time uniform rising of the potting compound through the board and a compact connection. Corresponding passages can directly over a receiving chamber for the ultrasonic transducer, z. B. an extension which is arranged in or on the first housing, are. This ensures that the potting compound also enters this receiving chamber and seals the ultrasonic transducer to the outside there.

Advantageously, the first housing may have an extension, in which the ultrasonic transducer is positioned, wherein the extension is at least partially immersed in the potting compound. As already explained above, is expediently potting compound within the extension to securely seal the ultrasonic transducer to the outside. By positioning the ultrasonic transducer in the extension, the ultrasonic measuring path within the first housing as well as the flow of the medium is not affected. The fact that the extension only partially immersed in the potting compound, it can be ensured at the same time that the ultrasonic transducer disposed therein does not come into contact with the potting compound or the air or gas enclosure is guaranteed.

With particular advantage, the extension can form a support for the calculator. As a result, the calculator is located over a large area, so that a stable mechanical connection of the two housing parts is made possible. Advantageously, the extension can be inclined or obliquely arranged on the first housing, so that at the same time a relatively large bearing surface for the calculator can be formed. In particular, the orientation of the extension to the support surface to z. B. 20 ° -70 °, z. B. by 45 °, inclined.

The extension can have a chamber for receiving the ultrasound transducer, in which the ultrasound transducer is positioned such that its surface normal N is inclined to the plane E of the arithmetic unit or to the plane A of a display element of the arithmetic unit. This design has the advantage that the ultrasonic transducer is no longer positioned at the uppermost position of the space through which the medium flows, but deeper. Accordingly, the gas bubbles present in the medium collect at an upper stall in the interior of the measuring section, where they have no effect on the accuracy of the measurement. At the same time, however, the calculator and thus also the display device, remain at the highest point, so that it is still easy to read. The lateral angular offset of the surface normal N of the ultrasonic transducer can be perpendicular to the plane E or the plane A in an angular range between 20 ° -70 °, preferably 30 ° -60 °, particularly preferably 40 ° -50 °. For example, the angle can be 45 °. With the inclined arrangement of the extension thus advantageously two functions can be fulfilled simultaneously, namely on the one hand the provision of a large bearing surface of the first housing for the arithmetic unit and on the other the inclined arrangement of the ultrasonic transducer to disturbances or measurement errors due to gas accumulation in the upper region of the flowed through To avoid space.

Conveniently, the ultrasonic transducer by means of a holding part in the extension, preferably spring-loaded, be held. As a result, the ultrasonic transducer is stably and securely held in position.

The contacting of the ultrasonic transducer can be effected via electrodes, the connecting parts or connecting wires protrude from the extension and thereby directly contactable with the circuit board. In this way, direct, short electrical wiring paths between the ultrasonic transducer and electronics can be created, so that z. B. can be dispensed with expensive coaxial cable. The protruding from the extension connecting parts can be soldered directly to the electronics or the board.

Expediently, the connection part of the electrode arranged on the back of the ultrasound transducer may comprise or cooperate with a spring element, so that the ultrasound transducer is securely held in its position by means of spring force and stabilized. The connection part can finally pass through the holding part and protrude from there from the extension. The connection part of the electrode arranged on the front side of the ultrasonic transducer can be guided laterally between the holding part and the inner wall of the chamber.

Advantageously, the ultrasonic transducer can be arranged such that it penetrates a region of the wall of the first housing. He is not directly connected to the flowing medium. The overhead casting for sealing the ultrasonic transducer is particularly suitable for such ultrasonic meters with wall penetrating.

The first housing may consist at least substantially of plastic. In particular, the region of the wall of the first housing, on which the ultrasonic transducer is arranged and the wall penetrated, consist of plastic. Plastic is particularly suitable for wall penetrating. The advantage of the ultrasonic transducer arranged outside the wall of the first housing is that the measuring path itself as well as the flow of the medium is not disturbed or influenced. In addition, a higher robustness of the device is achieved by eliminating the seal, which would be necessary in a bore in the housing wall in the arrangement of the ultrasonic transducer.

In the inventive method for producing a flowmeter for determining the flow rate of a flowing medium having a first housing, in which an ultrasonic measuring section is provided, along which a transit time measurement by means of at least one ultrasonic transducer for emitting or receiving ultrasonic signals is feasible, and a second housing, which includes an arithmetic unit with electronic components, by means of which a signal processing and / or signal evaluation is feasible, first the first housing is inserted with inserted ultrasonic transducer with a populated with electronic and / or electrical components board and inserted into the second housing and sealed by potting, wherein the potting compound seals the ultrasonic transducer located in the region of the first housing to the outside. This method can be carried out quickly and ensures a secure and permanent sealing of the ultrasonic transducers to the outside.

The casting takes place such that the second housing serves as a collecting reservoir for the potting compound during the pouring. Accordingly, the potting compound is filled in the upside-down second housing until the potting compound encloses at least the upper region of the first housing and thus also seals the ultra-converter. Subsequently, the entire arrangement is reversed again, so that the opening of the second housing is directed downward and the display device faces upward and is therefore readable.

Before casting, the electrodes of the ultrasonic transducer or its connection parts are contacted directly with the board. The use of additional cables is not required.

The invention is explained in more detail with reference to advantageous embodiments according to the drawing figures. These show:

1 : Exploded view of the flow meter in perspective view;

2 : schematic representation of the flow meter in section with wall penetrating;

3 : schematic representation of the flow meter in side view;

4 : schematic representation of the flow meter in section along the line IV-IV according to 3 with wall penetrating;

5 : schematic representation of the flow meter in section without wall penetrating;

6 : schematic representation of the flow meter in section along the line IV-IV according to 3 without wall penetrating as well

7a -I): Steps to make a flow meter according to 1 - 4 ,

The in 1 Flow meter shown with its parts is in its entirety by reference numeral 1 Mistake. It serves to determine the flow rate of a flowing medium and has two first housing 2 in which an ultrasonic measuring section 3 is provided along the transit time measurement by means of ultrasonic transducers 4 for transmitting or receiving ultrasonic signals is feasible. In a second housing 5 is a calculator 6 provided with electronic components, by means of which a signal processing and / or signal evaluation is feasible. In 1 is only the board from the calculator 9 illustrated for simplicity without electronic or electrical components. The ultrasonic transducers 4 are each located in the area of the first housing 2 , The second housing 5 is overhead with potting compound 7 at least partially filled, the potting compound 7 in the area of the first housing 2 located ultrasonic transducer 4 seals to the outside (see 2 and 4 ). By means of this construction are the ultrasonic transducers 4 as well as the electronics are protected against moisture penetrating from the outside. The potting can be done easily by the second housing 5 serves as collecting reservoir during the overhead grouting With reference numeral 26 are the reflectors, which serve to divert the ultrasonic signals characterized.

The potting compound 7 may conveniently be transparent or transparent, so that in the second housing 5 arranged display device 14 over which the potting compound 7 extends, still visible from the outside through the housing and remains readable. If the potting compound 7 is not transparent or transparent, must - preferably by providing a seal in particular foam between the display device 14 and second housing 5 - be taken to ensure that the potting compound 7 not in the room above the display 14 arrives. If the seal is also not transparent or transparent, it must be the actual display area of the display device 14 set free.

The second housing 5 has an opening 8th on, with the potting compound 7 partially in the area of the opening 8th is open. In this open area is the potting compound 7 just trained. The remaining area of the opening 8th is through an extension 12 in which the respective ultrasonic transducer 4 is arranged, covered. The exposed area of the potting compound 7 simplifies the entire construction of the flow meter 1 , whereby a cost-effective design is achieved. The exposed area of the potting compound 7 also has the advantage that during casting any air pockets in the potting compound 7 can escape easily.

In the area of the ultrasonic transducer 4 however, air is through the potting compound 7 locked in. This will create a contact between the ultrasonic transducer 4 and potting compound 7 avoided, causing disturbances due to attenuation of the ultrasonic transducer 4 be prevented.

The calculator 6 has a flat board 9 on, being between the board 9 and the second housing 5 Through openings 10 . 11 for the potting compound 7 are provided. In an embodiment not shown in the drawing figures also passages 10 . 11 in the board 9 be provided for yourself. So z. B. passages directly above the extension 12 or directly above a receiving chamber for the respective ultrasonic transducer 4 in the first case 2 is located. The passages 10 . 11 allow in any case, ie within the board 9 or between the board 9 and the second housing 5 , a passage of the potting compound 7 in overhead casting such that the second housing 5 or the ultrasonic transducers arranged therein 4 safe and free of bubbles are sealed against the environment. The passages 10 . 11 thus ensure a uniform and rapid potting and a secure sealing.

As already mentioned above, the respective first housing 2 an extension 12 on, in which the respective ultrasonic transducer 4 is positioned, with the extension 12 partly in the potting compound 7 dips. The potting compound 7 is also partially within the extension 12 in the chamber 13 in which the ultrasonic transducer 4 is arranged as from the drawing figures 2 . 4 . 5 and 6 shows, is the potting compound 7 up to a certain range or a certain height around the extension 12 as well as in the corresponding height or level within the extension 12 that is, the chamber 13 , The one in the chamber 13 arranged ultrasonic transducer 4 stands with the potting compound 7 not in contact, so that disturbances are avoided.

The extension 12 forms a circulation for the calculator 6 (see in particular 1 - 3 and 5 ). The large-scale arithmetic unit 6 enables a stable mechanical connection of both housing parts. The extension 12 has a bearing surface 23 on top of that by the ultrasonic transducer 4 defined contact surface is inclined by 45 °. As a result, a relatively large contact surface for the calculator 6 created.

The extension 12 for receiving an ultrasonic transducer 4 has a chamber 13 on, in which the respective ultrasonic transducer 4 is positioned such that its surface normal N to the plane E of the calculator 6 or to the level A of a display device 14 of the calculator 6 is inclined. This arrangement has the advantage that the ultrasonic transducer 4 is not positioned at the top position of the channel through which the medium flows, but laterally and deeper. Accordingly, the gas bubbles present in the medium, which always accumulate at the top, do not affect the accuracy of the measurement 14 with its level A remains well visible and easy to read through the transparent or transparent Vergoss. The surface normal N to the plane E of the arithmetic unit and to the level A of the display device is inclined at an angle of 45 °. By this inclined arrangement of the extension 12 at the same time becomes the large contact surface for the calculator described above 6 created.

The respective ultrasonic transducer 4 is by means of a holding part 15 in the extension 12 held spring loaded. For this purpose, according to the illustrated embodiment in 1 . 2 and 4 a spring element 20 between ultrasonic transducer 4 and holding part 15 arranged, which the ultrasonic transducer 4 holds securely in position without affecting its vibrations.

The contacting of the ultrasonic transducer 4 via electrodes 16 and 17 , their connecting parts 18 . 19 from the extension 12 stick out and directly with the board 9 contacted or soldered. In the 2 and 5 are the solder joints 25 shown on the board. Thus, the entire arrangement allows direct short electrical cabling paths between ultrasonic transducers 4 and electronics.

Instead of the arrangement of a separate spring element 20 it may be in an alternative embodiment z. B. also be provided that the connection part 18 even the one on the ultrasonic transducer 4 rear electrode 16 a spring element comprises, wherein this spring element is part of the connection part 18 is and z. B. with the electrode 16 connected is. The adjoining the spring element part of the connection part 18 can through the holding part 15 be guided and protrude from there upwards towards platinum.

According to the in the 2 and 4 illustrated embodiment durchschallt the ultrasonic transducer 4 an area 21 the wall 22 of the first housing 2 , The first case 2 consists of plastic, which is suitable for wall sound transmission.

In the in the 5 and 6 illustrated embodiment are the ultrasonic transducer 4 directly in contact with the flowing medium and lie directly on the flowed through space. There is no wall penetrating. The two variants show that the construction according to the invention can be realized with a flow meter with and without wall penetrating.

In 7 is the production process for a flowmeter according to the invention 1 with wall penetration in steps a) -i). The finished flow meter 1 includes a first housing 2 in which an ultrasonic measuring section 3 is provided along the one transit time measurement by means of two ultrasonic transducers 4 , which serve to send or receive ultrasound signals, is feasible, and a second housing 5 , which is an arithmetic unit 10 includes electronic components, by means of which a signal processing and / or signal evaluation is feasible (see 7i )).

In the manufacturing process, first, the first housing 2 provided, which has an extension 12 with a chamber 13 having. According to step b) is in the first housing 2 or in the chamber 13 an ultrasonic transducer 4 with the associated electrodes 16 . 17 as well as connecting parts 18 . 19 used. In step c), the spring element 20 inserted and by means of the holding part 15 pressed. In step d) becomes one with battery 24 , Display device 14 and other components populated board 9 (PCB) on the first case 2 put on, with the oblique top-side bearing surface 23 of the extension 12 is designed over a large area and thus a stable mechanical connection of board 9 and first housing 2 allows. In step e), the contacts of the outer ends of the connecting parts 18 . 19 soldered The solder joints are with reference numeral 25 Mistake. In step f) is the with the assembled board 9 connected first housing 2 in the second housing 5 used, this overall structure in step g) is rotated and turned upside down. in step h) becomes the second housing 5 by means of potting compound 7 so far shed that the potting compound 7 in the area of the first housing 2 located ultrasonic transducer 4 seals to the outside. The potting compound 7 penetrates partially into the chamber 13 and surrounds the extension also partially 12 , The second housing 5 serves as a collecting reservoir for the potting compound during potting 7 ,

After curing of the potting compound 7 the flow meter is ready (step i)), so that the flow meter with the upward facing indicator 14 can be installed.

LIST OF REFERENCE NUMBERS

1

Flowmeter

2

first housing

3

Ultrasonic measurement section

4

ultrasound transducer

5

second housing

6

calculator

7

potting compound

8th

opening

9

circuit board

10

Through opening

11

Through opening

12

extension

13

chamber

14

display

15

holding part

16

electrode

17

electrode

18

connector

19

connector

20

spring element

21

Area

22

wall

23

bearing surface

24

battery

25

soldered point

26

reflector

27

air

Claims (14)

Flow meter ( 1 ) for determining the flow rate of a flowing medium with at least one first housing ( 2 ), in which an ultrasonic measuring section ( 3 ) is provided, along which a transit time measurement by means of at least one ultrasonic transducer ( 4 ), which is located in the area of first housing ( 2 ), for transmitting or receiving ultrasonic signals is feasible, a second housing ( 5 ), which is an arithmetic unit ( 8th ) with electronic components, by means of which a signal processing and / or signal evaluation is feasible, wherein the second housing ( 5 ) as collecting reservoir for potting compound ( 7 ) is formed and on the first housing ( 2 ) directed side an opening ( 8th ), through which the second housing ( 5 ) over head with potting compound ( 7 ) is at least partially filled, such that the potting compound ( 7 ) of the second housing ( 5 ) in the area of the first housing ( 2 ) ultrasonic transducer ( 4 ) seals to the outside. Flowmeter according to claim 1, characterized in that the potting compound ( 7 ) at least partially in the region of the opening ( 8th ) is open. Flow meter according to at least one of the preceding claims, characterized in that in the region of the ultrasonic transducer ( 4 ) Air or gas through the potting compound ( 7 ) is included. Flowmeter according to at least one of the preceding claims, characterized in that the calculating unit ( 6 ) a preferably flat board ( 9 ) and at least one, preferably a plurality of passage openings ( 10 . 11 ) in the board ( 9 ) and / or between the board ( 9 ) and the second housing ( 5 ) is / are provided. Flow meter according to at least one of the preceding claims, characterized in that the first housing ( 2 ) an extension ( 12 ), in which the ultrasonic transducer ( 4 ), and the extension ( 12 ) at least partially into the potting compound ( 7 immersed). Flow meter according to claim 5, characterized in that the extension ( 12 ) an edition for the calculator ( 6 ). Flow meter according to at least one of claims 5 or 6, characterized in that the extension ( 12 ) for receiving the ultrasonic transducer ( 4 ) a chamber ( 13 ), in which the ultrasonic transducer ( 4 ) is positioned such that its surface normal N to plane E of the calculator ( 6 ) or to the level A of a display device ( 14 ) of the calculator ( 6 ) is inclined. Flow meter according to at least one of claims 5-7, characterized in that the ultrasonic transducer ( 4 ) by means of a holding part ( 15 ) in the extension ( 12 ), preferably spring-loaded, is held. Flow meter according to at least one of claims 5-8, characterized in that the contacting of the ultrasonic transducer ( 4 ) via electrodes ( 16 . 17 ), whose connecting parts ( 18 . 19 ) from the extension ( 12 protrude) and thereby directly with a board ( 9 ) are contactable. Flow meter according to claim 9, characterized in that the connecting part ( 18 ) on the ultrasonic transducer ( 4 ) rear electrode ( 16 ) a spring element ( 20 ) or cooperates with such. Flow meter according to at least one of the preceding claims, characterized in that the ultrasonic transducer ( 4 ) an area ( 21 ) of the wall ( 22 ) of the first housing ( 2 ). Flow meter according to at least one of the preceding claims, characterized in that the first housing ( 2 ), at least substantially, consists of plastic. Method for producing a flow meter for determining the flow rate of a flowing medium with a first housing ( 2 ), in which an ultrasonic measuring section ( 3 ) is provided, along which a transit time measurement by means of at least one ultrasonic transducer ( 4 ) for emitting or receiving ultrasonic signals, and a second housing ( 5 ), which is an arithmetic unit ( 10 ) with electronic components, by means of which a signal processing and / or signal evaluation is feasible, characterized in that the first housing ( 2 ) with inserted ultrasonic transducer ( 4 ) and connected to a populated board ( 9 ) in the second, as collecting reservoir for casting compound ( 7 ) serving housings ( 5 ) and over head by means of potting compound ( 7 ), in such a way that the potting compound ( 7 ) in the area of the first housing ( 2 ) ultrasonic transducer ( 4 ) seals to the outside. Method according to claim 13, characterized in that the electrodes ( 16 . 17 ) of the ultrasonic transducer ( 4 ) or their connecting parts ( 18 . 19 ) directly with the board ( 9 ) are contacted.

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