CA1167283A

CA1167283A - Fluid flow meter

Info

Publication number: CA1167283A
Application number: CA000399636A
Authority: CA
Inventors: Glen Brand
Original assignee: Individual
Current assignee: Individual
Priority date: 1981-04-16
Filing date: 1982-03-29
Publication date: 1984-05-15
Also published as: GB2097133B; GB2097133A; US4393723A; FR2504259A1; DE3213702A1; IT8248226A0; IT1147683B; JPS589025A

Abstract

ABSTRACT OF THE DISCLOSURE
A fluid flow meter with a turbine rotationally supported within a transparent cylindrical housing and biased against its rotational response to the flow of fluid whereby flow rates are read on a circumferential scale mounted on the turbine. In an alternative embodiment, in addition to rotational movement the turbine is biased against axial movement whereby a helical scale mounted on the turbine may be calibrated and read along more than a single 360° of angular movement. In another alternative embodiment, a compression spring in combination with a threaded axle which mates with a threaded cavity within the turbine, provides helical displacement of the turbine for permitting the calibration of more than 360° of angular rotation.

Description

BACKGROUND OF THE INVENTION
This invention relates generally to fluid flow meters and more particularly to meters which t~anslate the proportionate travel of an object within the meter housing which is biased against the direction of flow of the fluid being measured.
A simple and inexpensive meter of this type is comprised of a bullet-nosed object held against the fluid flow by a compression spring which is centrally supported within a housing. The downstream defleetion of the object is calibrated and read through a window in the housing or transparent length of pipe. Although these devices have generally performed satisfactorily, for more accuracy a longer more precise spring is required, sometimes thus precluding their practicality where space is a 10 factor. Also their inherent economy is compromised since the cost of springs which will perform adequately increases geometrically as they are lengthened.
More complex meters of this type such as that disclosed in U. S. Patent No. 4,041,891, employ propellers which are biased against the direction of flow by torsion springs. However, in these devices the springs are typically located outside the housing in which the fluid is flowing, thus requiring special treatment to seal off a dry spring and indicator chamber and requiring other additional components in the form of seals, gears and various moving parts.
Other meters employ propellers by measuring their rotational speed and also must transfer readings externally by structures more complex than a window or 20 transparent length of pipe. Some of these struetures include routing the liquid out of its general path of flow so that the propeller can be normal thereto, use of a worm gear in order that the propeller can be normal to the general path of fluid flow, and counting electronic pulses transmitted through a non-conductive housing by ferro-magnetic elements on the propeller. All of these latter types of rate of flow meters can be relatively accurate in a confined space, but also are complex devices requiring high initial cost and expensive maintenance.

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2~3 In one embodiment, the present invention provides a fluid flow meter, comprising: a turbine having a hub for mount-ing on a supporting structure affixed to the interior of a housing, said housing having inlet and outlet ends, for both rotational and downstream movement of said turbine in response to the rate of flow of fluid through said housing; means for biasing said turbine in a direction opposite to that produced by said fluid flow; and means for determining the combined rotational and downstream displacement of said turbine, whereby said flo~ rate can be translated to more than 360 of angular displacement of said turbine.
Another embodiment of this invention provides a fluid flow meter, comprising: a cylindrical housing having an inlet and outlet at opposite ends thereof; a supporting structure affixed to the interior of said housing, including: a base member extending to the central area of said housing; and an axle protruding upstream from said central area; a turbine having a hub open at its downstream end mounted on said axle; means within said housing for biasing said turbine in a direction opposite to that produced by the fluid flow; and means for determining the displacement of said turbine.
Yet another embodiment of this invention provides a mechanical fluid flow rate indicator comprising a housing having :` ~ :
; a transparent barrel defining a flow axis, said harrel having a fluid inlet and a fluid outlet spaced apart along said axis, a turbine impeller mounted in said barrel for limited angular displacement upon one end of an axle which is cantîlevered up- -stream along said flow axis from a supporting structure affixed . .
to the interior of the housing, said turbine impeller being .

displaced in response to the rate of flow of fluid through said barrel; means which biases said turbine impeller in a direction opposite the movement of the turbine impeller produced by said : ~ .

7~2~3 fluid flow; and indicia visible from outside the barrel for indicating the amount of displacement of said turbine impeller in response to said fluid flow.

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~ ~ ' BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a perspective view of the preferred embodiment of my fluid flow meter in its assembled form;
Fig. 2 is an exploded perspective view showing the preferred embodiment of my fluid flow meter, which indicates the relative position of its elements, and which includes a partial internal view of a housing member;
Fig. 3 is a cross-sectional view of the preferred embodiment of my fluid flow meter taken along line 3-3 of Fig. 1;
Fig. 4 is a cross-sectional view of an alternative embodiment of my fluid 10 flow meter which indicates its differences with the preferred embodiment of Figs. 1, 2 and 3; and Fig. 5 is a cross-sectional view of another alternative embodiment of my fluid flow meter which indicates its differences with the preferred embodiment of Figs. 1, 2 and 3.

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DESCRIPTION OF THE PREFERRED AND ~LTE~NATIVE EMBODIMEN~S
Referring now to the drawings wherein like numerals designate identical or corresponding parts throughout the se~leral views, and more particularly to Fig. 1, whereon the meter is depicted generally at 10, its key elements are viewed enclosed within a housing assembly 20 which is comprised of a transparent cylindrical tube 21 having an inlet end 22 and an outlet end 23, two identical bolt-head fittings 24 for threaded conjoinment within either end of transparent tube 21, and identical rubber seal rings 26 for use with each fitting 24. As can be best seen in Fig. 2, bolt-head fitting 24 is generally cylindrical in shape having a central hollow core, its wall being 10 L-shaped in cross section, the horizontal leg of the "L" representing an external bolt-head shaped projection 27 for the application of torque with a wrench and the vertical leg of the "L" representing the wall of the hollow cylinder having thereon external threads 28 distal the bolt-head configuration 27 for cooperation with internal threads in either end of tube 21 and internal threads 25 thereon proximal the bolt-head configuration 27 for conjoinment with the adjacent upstream and downstreqm fluid conduits. Between configuration 27 and external threads 28 is a seal ring retainer space 29 for the location of compressible seal ring 26. The bolt-head fitting 24 makes it possible to adjustably install the fluid ~low meter 10 within a standard section of pipe through which a fluid is conducted by removing a section thereof appropriate in 2~ length and appropriately threading freed ends of the conduit.
Within housing assembly 20 and co-axial with it is eylindrical scale 31 which includes numerical designations 32 for reading comparatiYe flow rates against hairline mark 15, said mark 15 being located on the surface of transparent tube 21 and adjacent to numerical designations 32. A novel feature of my flow meter is the circumferential translation onto scale 31 of the linear rate of flow of a fluid through the meter, thus making available the full circumference of cylindrical scale 31 for calibrating flow rates. The means by whieh cylindrical scale 31 rotates in response to ehanges in fluid flow rates will be explained hereinafter.
Visible in Figs. 1, 2 and 3, but best seen in Fig. 2 is supporting structure 30 base 33. ~ase 33 in this embodiment is a three-legged spider which may be integral with or affixed in a well known matter to the inside wall of cylinder 21 adjacent the threads at outlet end 23. Supporting structure base 33 has a center cylindrical axle supporting cavity 34 in its upstream face which is co-axial with housing assembly 2D

and which can be seen in Fig. 3 and is best depicted by dashed lines in Fig. 2. Rigidly supported within cavity 34 is an axle 36. Axle 36 could be integral with supporting structure base 33. The use of either a free or an integral axle being dictated by other than functional considerations.
As can be seen in Fig. 2, axle 36 has molmted thereon in spaced apart relationship two O-rings 37 for the provision of a minimal frictional surface upon which a turbine assembly, designated generally at 30, can revolve in response to the flow of a fluid through the meter. Turbine assembly 30 is comprised of a hub member 38, vane members 39 and cylindrical scale members 31 which was described hereinabove. Hub member 38 has an external axially centered, cylindrical portion 41 with a c~axial cylindrical cavity 42 for the insertion therein of the upstream end of axle 36 and bearing O-rings 37 and for the affixation to the downstream end thereof of the central end 43 of torsion spring 44 by its insertion into slot 35 of constriction 45.
To the internal extension 46 of hub 38 within turbine assembly 30 are affixed equi-angular radially outwardly directed vanes 39 and within internal extension 46 of hub 38 cylindrical cavity 42 is continued so far as to prevent hub 38 from being moved by fluid pressure against supporting structure base 33. This relationship can best be appreciated by viewing Fig. 3 which shows the length of cylindrical cavity 42 to be slightly less than the length of the portion of axle 36 which protrudes upstream from supporting structure base 33 plus the diameter of a ball bearing 47. Also best understood by viewing Fig. 3 is the fact that frictional impediments to the accuracy of ; my meter are minimi2ed by the use of but two O-ring bearings 37 and a singie ball bearing 47j O-rings 37 having a surface of Teflon or the like. Where hub 38 protrudes upstream beyond vanes 39 and cylindrical scale 31, it is bullet-nosed in configuration for~ reducing turbulence and maintaining the even balance of turbine assembly 30 upon axle 36~ Cylindrical scale 31 which is co-axial with housing assembly 20, axle 36, and hub 38 is affixed at its internal wall to the radial extension of each of the vanes 39.
To complete this preferred embodiment 10 of my meter, turbine assembly 30 and the internal wall of tube 21 of housing assembly 20 is connected to torsian spring 44 at its peripheral end 48 through a post 49 which protrudes upstream from one leg of supporting structure base 33. It should be appreciated that the connection to tube 21 does not necessarily have to be done through base 33. In the :~
embodiment depicted herein, the vanes 39 are conformed so as to turn turbine ~ Trc~ d~ i~r ~

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~L~ tjt.~2~3 assembly 30 clockwise with respect to the upstream end of housing assembly 20 in response to the flow of a fluid through the meter, and torsion spring 44 is oriented so as to bias turbine assembly 30 in the counter-clockwise direction.
Referring now to Fig. 4, an alternative embodiment of my fluid flow meter is depicted generally at lOa. The following description of this embodiment will rely on the foregoing description of the preferred embodiment 10 for elements which are structuraUy and functionally the same by merely appending an "a" to the comparable numerical designations. Analogous elements will also employ the appended "a" with essential differences only described.

Housing assembly 20a is shown to differ from housing assembly 20 of the preferred embodiment 10, in that transparent tube 21a is longer than its counterpart, tube 21 of housing assembly 20, in relation to the comparative lengths of its hub member 38a and hub member 39. Supporting base member 33a being located the same relative distance from the outlet end 23a of tube 21a as its counterpart, supporting base member 33 of housing assembly 20 is from outlet end 23, space downstream from hub member 38a is provided for the movement of hub member 38a along axle 36a.
In this embodiment of my fluid flow meter, turbine assembly 30a is in the same relative position with respect to inlet end 22a of housing assembly 20a as is turbine assembly 30 with respect to housing assembly 20 in the preferred embodi-20 ment 10 when the fluid flow rate is zero. In embodiment 10a an addtional element inthe form of a compression spring 51 is located within cavity 42a and interposed between ball bearing 47a and the upstream end of cavity 42a. This compression spring is of a design which will enable it to resist downstream movement of turbine assembly 30a a sufficient distance to enable number designations 32a aligned helically on cylindrical scale 31a to be read against a hairline mark 15a (not visible in Fig. 4) located on the surface of transparent tube 21a at flow rates above that which cause turbine assembly 30a to revolve more than 360.
External cylindrical portion 41a of hub member 38a being further from supporting base member 33a, as set forth hereinabove, it is necessary that post 49a be 30 longer than post 49 of preferred embodiment 10. It should be appreeiated that to permit hub assembly 30a to move axially downstream it will be necessary for torsion spring 44a to flex somewhat in the downstream direction. In so flexing, torsion spring 44a will actually he assisting compression spring 51 in biasing turbine assembly 30a against downstream axial movement resulting from higher fluid flow rates. Whatever affect the downstream flexing of torsion spring 4~a has on turbine assembly 30a will be resolved, along with that of compression .spring 51, when the meter is calibrated.
It should also be appreciated that greater than 360 of angular motion could be calibrated on a scale with number designations in helical arrangement, such as in alternate embodiment lOa withou~ a compression spring such as spring 51 thereof, by changing only the length of transparent tube 20 and post 49 of pre~erred embodiment 10 and relying only on downstPeam flexing of torsion spring 44a for the 10 appropriate bias against downstream axial movement of turbine assembly 30. A
further modification which would avoid problems resulting from the flexing of a flat torsion spring would be to leave post 49 its original length and replace the flat torsion spring with a helical or cone-shaped torsion spring with its base oriented downstream.
A flatter helial torsion spring might also be used in embodiment lOa with the length of post 49a adjusted accordingly.
Referring now to Fig. 5, whereon another alternate embodiment of the meter is depicted generally at lOb, and as in alternative embodiment lOa, only those elements which are different in a functional and significant way are to be described, another embodiment which permits the calibration of more than 360 of angular 20 rotation of turbine assembly 30b is shown. In the embodiment lOb, cavity 42b is threaded at a pitch equal to the desired spacing of the annular segments of helically arranged numerical designations 32b on cylindrical scale 31b. Axle 36b is of a diameter and threaded at a pitch for threaded cooperation with cavity 42b, its length being such that adequate axial movement of turbine assembly 30b is available between its zero-flow rate position and its highest flow rate positi~n. In the alternative embodiment 10b, compression spring 51b surrounds threaded aa~le 36b and is retained at its downstream end by a retaining collar 52 mounted on supporting structure 33b and at its upstream end by retaining collar 53 mounted on the downstream end of hub 38b adjacent and surrounding cavity 42b. Vanes 39b of turbine assembly 3Ub are 30 pitched sympathetically with the threads of axle 36b so as to overcome inertia in turbine assembly 30b. Compression spring 51b in combination with the threaded mating of turbine assembly 30b and threaded axle 36b will permit the calibration and metering of flow rates over a helical course such that more than 360 of angular and 2~3 axial movement of turbine assembly 30b may be encompassed. While embodiment 10b employs a turbine as does the other two embodiments of my invention disclosed herein, it is the mating threads on axle 36b and in cavity 42b, upon which it relies for its rotational movement, not turbine assembly 30b; hence9 other objects than a turbine which would respond to the rate of flow of fluid through the meter could be employed, the turbine providing the functions of overcoming inertia and friction along the threads.
It should also be appreciated that both alternative embodiments 10a and 10b can be constructed so as to be read along a helical scale with any number of 10 annular segments in excess of 360 although a scale of but two revolutions is depicted in ~igs. 4 and 5. It is also well known in the art that magnetic, electronic, or other structures can substitute for springs to provide biasing to the turbine in my fluid flow meter.
Obvious numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practised otherwise than as specifically described herein.

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Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A fluid flow meter, comprising:
a turbine having a hub for mounting on a supporting structure affixed to the interior of a housing, said housing having inlet and outlet ends, for both rotational and downstream movement of said turbine in response to the rate of flow of fluid through said housing;
means for biasing said turbine in a direction opposite to that produced by said fluid flow; and means for determining the combined rotational and downstream displacement of said turbine, whereby said flow rate can be translated to more than 360° of angular displacement of said turbine.

2 The fluid flow meter of Claim 1 wherein said biasing means includes a compression spring interposed between said turbine and said supporting structure and a torsion spring affixed at its central end to the hub of said turbine and at its peripheral end to the interior of said housing.

3. The fluid flow meter of Claim 1 wherein said supporting structure includes:
a base member extending to the central area of said housing; and a threaded axle protruding upstream from said base member, the hub of said turbine having interior threads corres-pounding with said axle threads; and said biasing means is a compression spring interposed between said turbine and said base member.

4. The fluid flow meter of Claim 1, 2 or 3 wherein said displacement determining means includes a transparent portion of said housing and a means coaxial with and mounted on said tur-bine for displaying comparative flow rates.

5. The fluid flow meter of Claim 1, 2 or 3, wherein said displacement determining means includes a transparent portion of said housing and a means coaxial with and mounted on said turbine for displaying comparative flow rates, and wherein the displacement determining means further comprises a helical scale mounted on said flow rate displaying means.

6. A fluid flow meter, comprising:
a cylindrical housing having an inlet and outlet at opposite ends thereof;
a supporting structure affixed to the interior of said housing, including:
a base member extending to the central area of said housing; and an axle protruding upstream from said central area;
a turbine having a hub open at its downstream end mounted on said axle;
means within said housing for biasing said turbine in a direction opposite to that produced by the fluid flow; and means for determining the displacement of said turbine.

7. The fluid flow meter of Claim 6 wherein said supporting structure further includes a plurality of spaced apart O-rings mounted on said axle for bearing contact with the hub of said turbine.

8. The fluid flow meter of Claim 7 wherein said supporting structure further includes bearing means interposed between the upstream end of said axle and the interior of the hub of said turbine.

9. The fluid flow meter of Claim 8 wherein said biasing means is a torsion spring affixed at its peripheral end to the interior of said housing and at its central end to the hub of said turbine.

10. A mechanical fluid flow rate indicator comprising a housing having a transparent barrel defining a flow axis, said barrel having a fluid inlet and a fluid outlet spaced apart along said axis, a turbine impeller mounted in said barrel for limited angular displacement upon one end of an axle which is cantilevered upstream along said flow axis from a supporting structure affixed to the interior of the housing, said turbine impeller being displaced in response to the rate of flow of fluid through said barrel; means which biases said turbine impeller in a direction opposite the movement of the turbine impeller produced by said fluid flow; and indicia visible from outside the barrel for indicating the amount of displacement of said turbine impeller in response to said fluid flow.