Flow rate measuring apparatus for fluid media

p0001The invention relates to a flow rate measuring device for fluid media.

p0002Flow rate measuring means for fluid media that use ultrasonic waves for flow measurement are known from the prior art, for example <patcit id="pcit0001" dnum="DE20107894U1"><text>DE 201 07 894 U1</text></patcit>. <patcit id="pcit0002" dnum="EP1493998A2"><text>EP 1493998 A2</text></patcit> or the Danish utility model specification 38 808 known. The device contains a flow-through of the medium measured section, at opposite ends thereof deflecting mirrors are provided. Via the deflecting mirror the sound waves of the ultrasonic transducer can be deflected in the measuring section. In the apparatus of the Danish utility model specification 38 808, the deflection mirror are held by multi-piece reflector inserts, which are mounted at right angles to the flow-through measurement section in bores in the housing inner wall of the flow meter.

p0003The design effort for production and assembly of reflector inserts for deflecting is costly.

p0004The present invention has for its object, a flow rate measuring device which it combines the simple design with ease of handling in the preamble claim 1 to provide the type mentioned.

p0005The invention solves this problem by a flow rate measuring device according to claim 1. Preferred embodiments of the invention can be found in the dependent claims. Thereafter, the deflection mirror on a support arm which is supported between the housing inner wall and the measuring tube and the support arm is designed for insertion in a space between the measuring tube and the housing inner wall. The inserted support arm is then preferably parallel to the measuring tube or the flow-through measuring section oriented.

p0006The support arm may have any shape which enables supporting of the deflecting mirror. The support arm can, for example, as a pin or even surface, be in the form of a Tragerarmplatte with a front and back. In the last case are in the assembled state of the front side, the outer wall of the measuring tube and the rear side opposite to the housing inner wall.

p0007The angle between the support arm and the deflection mirror depends in relation to the deflection mirror and the measurement section essentially on the positioning of the ultrasonic transducer. At right angle reflection of the sound waves of the ultrasonic transducer through the front side of the deflection mirror in the measurement path, the angle between the support arm and the front of the deflection mirror preferably about 135 ° when the support arm is oriented parallel to the measuring tube or the flow-through measuring section. In general, it will be necessary that the angle between the support arm and the front of the deflection mirror 45 ° -150 °, preferably 90 ° -135 °.

p0008the invention of the reflecting mirror and its support arm Further, according to a preferred feature integral, this simplifies a much prepare the construction of the flow rate measuring device and allows the other folding mirror and the support arm in a single operation. The invention has recognized that bestimmta materials such as stainless steel sheet, excellent both as a reflecting mirror, as are also suitable as support arm. Thus, deflecting mirror and support arm may be integrally stamped from stainless steel sheet, before subsequently whose reflection properties can be improved by polishing the front side of the deflection mirror and the support arm is angled relative to the deflecting mirror.

p0009The longer the distance is, with the support arm between the measuring tube and the inner housing wall is held, the better the support arm is secured against changes in position. For this reason, the carrier arm according to a preferred embodiment of the invention over a length of at least 1.0, preferably 1.5, particularly preferably supported 2.0 the width of the diameter of the measuring tube between the housing inner wall and the measuring tube.

p0010In order to keep the measuring tube in the housing and fix, the measuring tube according to the invention on its outer wall spacers, which are in direct contact with the housing inner wall. These spacers can be formed or rib, for example, nose-like and engage in axial grooves or corrugation on the housing inner wall.

p0011A positioning and fixing of the measuring tube in the housing can also be effected in that the measuring tube over a portion of the periphery has a continuation section with receptacle for a head portion of the ultrasonic transducer. The sound waves radiating head region of the integrated into the housing ultrasonic transducer thus breaks through both the housing inner wall, and the continuation of the range of the measuring tube. This is the position the measuring tube and the deflection mirror, which is held by the supported between the measuring tube and the housing inner wall support arm, fixed with respect to the ultrasonic transducer. Measuring inaccuracies or false readings due to an unwanted change in position of the deflection mirror with respect to the ultrasonic transducers in the course of use, can thus be avoided.

p0012To reduce measurement inaccuracies founded turbulence of flowing past the deflecting mirrors fluid medium flow conditioner can be used. For example, the rear side of the deflection by appropriate attachments are designed verwirbelungsberuhigend.

p0013Embodiments are illustrated below with reference to drawings. Show it:<dl id="dl0001"><dt>Fig. 1</dt><dd>an interrupted cut long through the housing in the end regions of the measuring tube;</dd><dt>FIG. 2</dt><dd>a partial section through the housing already in the end of the measuring tube to a further embodiment of the invention;</dd><dt>Fig. 3</dt><dd>a section transversely through the housing; </dd><dt>Fig. 4</dt><dd>a section transversely through the housing taken along a line IV-IV from <figref idrefs="f0001">Fig. 1</figref> ;</dd><dt>Fig. 5</dt><dd>Support arm and mirror (in one piece);</dd><dt>Fig. 6</dt><dd>Support arm and mirror (in one piece), with hood;</dd><dt>Fig. 7</dt><dd>a partial section through the housing already in the end of the measuring tube to a further embodiment of the invention.</dd></dl>

p0014<figref idrefs="f0001">Fig. 1</figref> and <figref idrefs="f0004">4</figref> show schematically the construction of a flow rate measuring device for fluid media. The flow rate measuring device has a housing 1, whose interior is bounded by a casing inner wall of the second In the interior of a measuring tube 3 is arranged. In the vicinity of both ends of the measuring tube 3, the housing 1 seats for the ultrasonic transducer 5, the break with their head area, the housing inner wall. Seals 18, for example from the prior art known quad rings seal the existing between the ultrasonic transducer 5 and the housing 1 interspaces. Seals 18 also seal the two-part measuring tube 3 from the contact area of ​​both parts and are secured by a circumferential collar 19 on the measuring tube. 3 As shown in particular in<figref idrefs="f0004">Fig. 4</figref> to see the peripheral collar 19 in the ultrasonic transducer 5 opposite region was suspended at when required withdrawal of the measuring tube 3 at the ultrasonic transducer 5 past allow. The ultrasonic transducer opposite a deflection mirror 6 having a front face 7 and a rear side 8 is arranged. About the front sides 7 of the deflection mirror 6, the sound waves of the ultrasound transducer 5 are diverted into the measuring section. 4 The deflection mirror 6 is held by a support arm. 9 The support arm 9 has a front side 10 and a back side 11. The deflection mirror 6 is formed integrally with the support arm. 9 The support arm 9, which has an angle of about 135 ° relative to the front face 7 of the deflection mirror 6, is held in an intermediate space between the housing inner wall 2 and the measuring tube 3rd In this case, each of the front face 10 and the outer wall of the measuring tube 3 and the rear side 11 and the inner housing wall 2 are opposite.

p0015The in <figref idrefs="f0001">Fig.1</figref> and <figref idrefs="f0004">4</figref> Illustrated embodiment is easy to handle due to the simple design, maintain and repair. Thus, measuring tube 3, support arm 9 can be removed with the reflecting mirror 6 as a unit or individually through the side opening of the housing 1 and the ultrasonic transducer 5 over. An important advantage of this construction is that the so-consuming development of ultrasonic transducers 5 can be avoided in order to access the measuring tube 3 and the reflecting mirror 6 can.

p0016In <figref idrefs="f0004">Fig. 4</figref> is further shown that the support arm 9 in a guide 12, formed of a groove with a groove base 17 in the housing inner wall 2 on the one hand, and on the opposite side of Tragerarms 9 by a disposed on the outer wall of the measuring tube 3 saddle piece 15 having a flat bottom surface , to be led. On these surfaces, the carrier arm 9 is located with its front side 10 and its rear side 11 binding to.

p0017In a further embodiment according to <figref idrefs="f0002">FIG. 2</figref> has the flow tube 3, a return portion 14 which extends over part of the circumference of the measuring tube 3 at the pipe end and having a receptacle for the sound waves radiating head portion of the ultrasonic transducer. 5

p0018The measuring tube 3 also has spacers 13 (s. <figref idrefs="f0003">Fig. 3</figref> and <figref idrefs="f0004">4</figref>), Which is not shown in (engageable) axial grooves of the inner housing wall second In<figref idrefs="f0003">Fig. 3</figref> is the front 10 of the support arm 9 against a flattening at the Au βenwand of the measuring tube. 3 That is, the opposing surfaces abut each other and are congruent in the sense of the present invention. Simultaneously, the carrier arm 9 according to the invention carried out in the guide formed by the two spacers 13 of the measuring tube. 3 The rear side 11 of the support arm 9 is rounded at the side edges and thus has a larger contact area on the surface of the inner housing wall 2. Thus, the positioning and fixing of Tragerarms between measuring tube 3 and the housing inner wall 2 is supported.

p0019<figref idrefs="f0005">Fig. 5</figref> and <figref idrefs="f0006">6</figref> show a detailed representation of the deflection mirror 6 with support arm 9. The support arm 9 has on its longitudinal sides semicircular recordings on, can engage in the corresponding regions of the outer wall of the measuring pipe 3 (not shown). This is a fixed connection, quasi, which links between support arm 9 and the measuring tube. 3 The deflection mirror 6 has in relation to the supporting arm 9 in the region of the solid line by an angle of 135 °, which is not visible in plan view. The deflection mirror 6 may be a flow stabilizer 16 mounted on its rear side 8 in the form of a shoe-like cover for a vertebrate poor flow steering, which the front of the deflection mirror 7 6 encompassing border areas in<figref idrefs="f0006">Fig. 6</figref> are shown. The use of the shoe-like cover 16 as an integral part of the in<figref idrefs="f0002">FIG. 2</figref> Embodiment shown in <figref idrefs="f0007">Fig. 7</figref> shown.