Cantilever beam, insertable, vortex meter sensor

A vortex fluid flowmeter comprising in combination:

• housing means having a conduit for fluid flow therethrough;
• bluff body means within said housing means and extending within said conduit, said bluff body means having slot means therethrough extending in a direction generally perpendicular to the direction of fluid flow;
• receptacle means having shoulder means within said bluff body means;
• sensor body means having bearing means forming a bearing surface, said sensor body means being receivable within said receptacle means with said bearing surface on said shoulder means;
• means for securing said sensor body means to said housing means;
• outer beam means affixed to said sensor body means and having a vane portion extending into said slot means for fluid flow contact, said outer beam means having at least the upper portion thereof formed as a hollow circular tube that serves as a flexure;
• inner beam means in spaced relation within the hollow upper portion of said outer beams means and secured therein at a point adjacent the bearing surface;
• flexure sensing means secured to said inner beam means for providing a signal indicative of the flexing of said lower portion of said first beam means upon flow of fluid through said conduit;
• said flexure sensing means is a strain gage beam member and a piezoelectric strain gage in contact therewith;
• said inner beam means has a generally circular cross-section and is in concentric relation within the upper portion of said outer beam means, and said strain gage beam member is generally bar-shaped and has a bar thickness much less than the diameter of said inner beam means;
• and
• said sensor body means has a generally hollow interior portion with said strain gage beam member extending therein, and a free end of said strain gage beam member is supported by a flexible link member secured thereto and to the adjacent inner wall of said sensor body means.

In a vortex sensor assembly for insertion into a flowmeter housing having a conduit for fluid flow there-through, with the housing having opening means with a shoulder portion through a wall thereof, said sensor assembly comprising the combination of:

• sensor body means having bearing means, said sensor body means being receivable within the opening means of said housing with said bearing means on said shoulder portion;
• first beam means having a hollow portion and being affixed to said sensor body means and having a vane portion for extending into said conduit for flexure in response to fluid flow;
• second beam means in spaced relation within the hollow portion of said first beam means and being secured therein at a point adjacent said bearing means;
• flexure sensing means operatively coupled to said second beam means for providing a signal indicative of the flexing of said first beam means upon flow of fluid through said conduit;
• said flexture sensing means include a strain gage beam member and a piezoelectric strain gage in contact therewith;
• said second beam means has a generally circular cross-section and is in concentric relation within the upper portion of said first beam means, and wherein said strain gage beam member is generally bar-shaped and has a bar thickness much less than the diameter of said second beam means;
• said sensor body means has a generally hollow interior portion with said strain gage beam member extending therein, and the free end of said strain gage beam member is supported by a flexible link member secured thereto and to the adjacent inner wall of said sensor body means;
• and
• said first, second and third beam means are configured, dimensioned and arranged for providing substantially zero stress on a portion of said third beam means in response to vibration of said flowmeter housing caused by pipeline vibration, and said electrical sensing means is placed on said portion of said third beam members.

A vortex sensor assembly for insertion into a flowmeter housing having a conduit for fluid flow therethrough, with the housing having opening means through a wall thereof, said sensor assembly comprising in combination:

• sensor body means receivable within the opening means of said housing;
• outer beam means operatively coupled to said sensor body means and having a vane portion for extending into said conduit for flexure in response to fluid flow;
• inner beam means operatively interconnected to said outer beam means for flexure upon flexure of said outer beam means;
• flexure sensing means operatively coupled to said inner beam means for providing a signal indicative of the flexing of said outer beam means upon flow of fluid through said conduit;
• said flexure sensing means comprising a strain gage beam member and a piezoelectric strain gage in contract therewith;
• said inner beam means has a generally circular cross-section and is in concentric relation within the upper portion of said outer beam means, and wherein said strain gage beam member is generally bar-shaped and has a bar thickness much less than the diameter of said inner beam means;
• said sensor body means has a generally hollow interior portion with said strain gage beam member extending therein, and a free end of said strain gage beam member is supported by a flexible link member secured thereto and to the adjacent inner wall of said sensor body means;
• and
• whereby said piezoelectric strain gage is positioned on the longitudinal portion of said bar-shaped beam member at a position sensitive to vortices and insensitive to vibration of said flowmeter housing.