GB1580569A

GB1580569A - Flowmeters

Info

Publication number: GB1580569A
Application number: GB3240077A
Authority: GB
Original assignee: Souriau et Cie
Current assignee: FCI France SA
Priority date: 1977-08-02
Filing date: 1977-08-02
Publication date: 1980-12-03

Description

(54) IMPROVEMENTS IN AND RELATING TO FLOWMETERS (71) We, SOURIAU ET CIE, a Company organized and existing under the Laws of France, of 13 Rue General Gallieni, 92100 Boulogne - Billancourt, France, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed to be particularly described in and by the following statement: The present invention relates to flowmeters for measuring the quantity and flow rate of fluids.

A known type of flowmeter comprises two housing portions which are secured together and in whose inner surfaces are formed respective annular grooves which combine to form an annular duct. Inlet and outlet ducts open into the annular duct for conducting fluid into and out of the annular duct. A body is located in the annular duct and is freely movable under the action of fluid flowing in the annular duct. The flow rate is measured by counting the number of complete orbits of the annular duct that the body makes in a preselected time period.

With flowmeters of this type it is not possible to adjust the relative positions of the inlet and outlet ducts.

Now, with flowmeters of the abovementioned type, the relative positioning of the inlet and outlet ducts determines how well the flowmeter operates, as is explained below.

If the locations at which the inlet and outlet ducts open into the annular duct are adjacent one another with the outlet duct immediately downstream of the inlet duct a portion of the fluid would pass directly from the inlet and to the outlet duct without circulating around the annular duct. On the contrary, should the locations be too far apart, this would result in a "dead" region occurring between the location where there would be virtually no circulation of fluid and where the body would be "trapped" with no possibility of escape. In either case, the flowmeter would not work satisfactorily.

Where the inlet duct opens into the annular duct close to but downstream of the opening of the outlet duct into the annular duct the body is carried continuously and smoothly around the annular duct traversing the portion of the annular duct between the inlet and outlet ducts under the action of the "pull" of the fluid entering through the inlet duct.

There is a specific relative positioning of the inlet and outlet ducts at which a flowmeter operates with maximum sensitivity, this positioning being liable to slight variatons from one flowmeter to another owing to machining tolerances for the size of the duct openings and the dimensions of the body.

The invention therefore seeks to provide an improved flowmeter.

Accordingly the present invention provides a flowmeter for measuring the flow of a fluid comprising a housing having first and second housing portions whose mating surfaces contain respective annular grooves which form together an annular duct, an inlet duct formed in one housing portion and opening into the annular duct for conducting fluid into the annular duct, an outlet duct formed in the other housing portion and opening into the annular duct for conducting fluid from the annular duct, and a body freely movable along the annular duct in response to fluid flow through the duct, the housing portions are secured to one another so as to be rotatable relative to one another about an axis substantially perpendicular to the plane in which the axis of said annular duct lies to vary the positions of the inlet and outlet ducts relative to one another.

In a preferred embodiment of the present invention the mobile body is in the form of a sphere with the separation between the closest edges of the inlet and outlet ducts at the locations where they open into the annular duct is about one half-diameter of the sphere. Preferably the two housing portions are secured together by means of a clamp in the form of a bolt and locking nut passing through the two housing portions centrally of the annular duct.

The present invention is further described hereinafter, by way of example, with reference to the accompanying drawings, in which: Fig. 1 is a plan view of a flowmeter according to the invention; Fig. 2 is an enlarged partial view of Fig.

1; and Fig. 3 is a sectional view along the line III-III of the flowmeter illustrated in Figure 1.

With reference with Fig. 1, the flowmeter 1 comprises an annular duct or channel 2 into which a fluid inlet duct 3 and a fluid outlet duct 4 opens at openings 31a and 4a, these ducts being respectively connected at 5 and 6 to external hydraulic circuits.

A body in the form of a sphere or ball 7 is located in the annular duct 2 and is freely movable around the duct 2 under the action of circulating fluid. Each complete orbit of the ball 7 is detected by optical means comprising a light source (not shown in the drawing) and a photo-sensor 8. The photosensor 8 is connected to electrical counting circuits which deliver an electrical signal proportional to the fluid flow or to the volume of the fluid flowing for a selected time period.

As it is best seen in Fig. 2, the crosssectional shape of the annular duct 2 is constant, but the cross-sectional area of ducts 3 and 4 decreases in the direction towards the duct 2. Thus, the openings 3a and 4a are smaller than the ball 7 in order to prevent the ball from escaping from duct 2 via either the ducts 3 and 4.

When used with a fluid such as petrol with a specific gravity of aproximately 0.75, the ball 7 can be made of superpolyamide (Nylon) of a specific gravity of approximately 1.12.

The duct 3 opens tangentially into the duct 2 with the opening of duct 4 being located upstream (in the direction of the ball displacement) and close to the opening of duct 3. The ducts 3 and 4 open into opposite sides of the duct 2.

The applicant has found that the nearest edges of the openings 3a and 4a should be spaced apart by a distance of approximately D/2, D being the diameter of the ball 7 (see Fig. 2).

As it is best seen in Fig. 3, the flowmeter 1 has a housing made of two plate-like housing portions 9 and 10 having abutting substantially planar surfaces 11 and 12.

Although these housing portions are illustrated as being discoidal in shape they may be of any suitable shape.

Two annular grooves 13 and 14 are formed in the respective surfaces 11 and 12 are joined together the grooves 13 and 14 such that when the two surfaces 11 and 12 combine to form the duct 2. These grooves are preferably formed during moulding of the housing portions 9 and 10 in order to provide grooves of a constant and uniform profile.

The inlet duct 3 and the outlet duct 4 are formed in the respective surfaces 11 and 12, either during the moulding of the housing portions 9 and 10 or at a later stage, for example by milling.

In addition, two further annular grooves are formed in the respective surfaces 11 and 12 to form an annular channel which has a smaller diameter than the annular duct 2 and which receives an annular seal 15. A further such channel may be provided for a second such annular seal 15.

The housing portions 9 and 10 being relatively thin, and thus liable to suffer from slight deformation, are clamped between two rigid disks 16 and 17 made for example of metal. The whole arrangement is fastened by means of a bolt 18 passing through axial holes 19 and 20 passing through the housing portions 9 and 10 and a nut 21 locked by a locking washer or ring 22. The axis of the bolt is substantially perpendicular to the plane in which the axis of the annular duct 2 lies. The metal disks 16 and 17 are of course provided with the necessary bores for the inlet and outlet ducts 3 and 4 and holes 19 and 20. A seal may be fitted between the ring 22 and the disk 17 and between the head of the bolt 18 and the disk 16.

The flowmeter can be adjusted as follows: The previously described assembly process is carried out by setting two opposite markers (not shown in the drawings) drawn on the radially outer edges of housing portions 9 and 10 for adjusting approximately the openings 3a and 4u ducts 3 and 4 into the required relative positions, i.e. spaced apart by a ball half-diameter, the nut 21 being unlocked.

The flowmeter is then put into operation and the operator manually rotates the housing portions relative to one another to adjust the instrument sensitivity for the lowest fluid flow value. The relative movement needed of the housing portions is of the order of a few tenths of a millimeter.

Once this adjustment has been carried out, the nut 21 is locked and the flowmeter is calibrated.

In particular, other means can be considered for adjusting the mutual angular position of both flanges. For example, as an alternative to or in addition to the bolt 18 one of the housing portions 9, 10 can be provided on its abutting surface with an upstanding spigot which projects into an arcuate recess or slot provided in the abutting surface of the other housing portion.

The length of the arcuate recess or slot determines the possible degree of relative rotation of the two housing portions. The spigot is conveniently formed integral with the said one housing portion.

In this case, when the bolt 18 is omitted, in order to facilitate relative rotation of the two housing portions one housing portion may be provided with a coaxial cylindrical portion raised on its abutting surface while the other housing portion has a correspondingly shaped recess with the grooves 13 and 14 being formed in the surfaces of the cylindrical portion and recess.

The co-operating surfaces 11 and 12 of the housing portions need not be planar but can be of any suitable shape such as conical, frusto-conical or cylindrical with the different grooves and being formed in these surfaces.

WHAT WE CLAIM IS: 1. A flowmeter for measuring the flow of a fluid comprising a housing having first and second housing portions whose mating surfaces contain respective annular grooves which together form an annular duct, an inlet duct formed in one housing portion and opening into the annular duct for conducting fluid into the annular duct, an outlet duct formed in the other housing portion and opening into the annular duct for conducting fluid from the annular duct, and a body freely movable along the annular duct in response to fluid flow through the duct, and wherein the housing portions are secured to one another so as to be rotatable relative to one another about an axis substantially perpendicular to the plane in which the axis of said annular duct lies to vary the positions of the inlet and outlet ducts relative to one another.

2. A flowmeter as claimed in claim 1, wherein said freely movable body is in the form of a sphere.

3. A flowmeter as claimed in claim 1 or 2, wherein the separation between the closest edges of the inlet and outlet ducts at the locations where they open into the annular ducts is approximately one half-diameter of the body.

4. A flowmeter as claimed in claim 1, 2 or 3, wherein the housing portions are sealed together by an annular insulating seal seated in mating grooves in the respective mating surfaces of the housing portions.

5. A flowmeter as claimed in any of claims 1 to 4, wherein the two housing portions are secured together by means of a clamp passing through the two housing portions centrally of the annular duct.

6. A flowmeter as claimed in claim 5, wherein said clamp comprises a bolt and locking nut.

7. A flowmeter as claimed in any of claims 1 to 6 wherein an arcuate recess is formed in the mating surface of one of said housing portions radially spaced from said axis of symmetry, said recess being engaged by a member projecting from the other housing portion whereby said recess determines the amount of relative rotation of the two housing portions.

8. A flowmeter as claimed in claim 7 wherein said member is integral with said other housing portion.

9. A flowmeter as claimed in any of claims 1 to 8, wherein the two housing portions are clamped between two stiffening metal plates.

10. A flowmeter as claimed in any of claims 1 to 9, wherein the fluid inlet duct opens tangentially into the annular duct.

11. A flowmeter for measuring the flow of a fluid substantially as hereinbefore described with reference to the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **.

position of both flanges. For example, as an alternative to or in addition to the bolt

18 one of the housing portions 9, 10 can be provided on its abutting surface with an upstanding spigot which projects into an arcuate recess or slot provided in the abutting surface of the other housing portion.

The length of the arcuate recess or slot determines the possible degree of relative rotation of the two housing portions. The spigot is conveniently formed integral with the said one housing portion.

In this case, when the bolt 18 is omitted, in order to facilitate relative rotation of the two housing portions one housing portion may be provided with a coaxial cylindrical portion raised on its abutting surface while the other housing portion has a correspondingly shaped recess with the grooves 13 and 14 being formed in the surfaces of the cylindrical portion and recess.

The co-operating surfaces 11 and 12 of the housing portions need not be planar but can be of any suitable shape such as conical, frusto-conical or cylindrical with the different grooves and being formed in these surfaces.

WHAT WE CLAIM IS: 1. A flowmeter for measuring the flow of a fluid comprising a housing having first and second housing portions whose mating surfaces contain respective annular grooves which together form an annular duct, an inlet duct formed in one housing portion and opening into the annular duct for conducting fluid into the annular duct, an outlet duct formed in the other housing portion and opening into the annular duct for conducting fluid from the annular duct, and a body freely movable along the annular duct in response to fluid flow through the duct, and wherein the housing portions are secured to one another so as to be rotatable relative to one another about an axis substantially perpendicular to the plane in which the axis of said annular duct lies to vary the positions of the inlet and outlet ducts relative to one another.
2. A flowmeter as claimed in claim 1, wherein said freely movable body is in the form of a sphere.
3. A flowmeter as claimed in claim 1 or 2, wherein the separation between the closest edges of the inlet and outlet ducts at the locations where they open into the annular ducts is approximately one half-diameter of the body.
4. A flowmeter as claimed in claim 1, 2 or 3, wherein the housing portions are sealed together by an annular insulating seal seated in mating grooves in the respective mating surfaces of the housing portions.
5. A flowmeter as claimed in any of claims 1 to 4, wherein the two housing portions are secured together by means of a clamp passing through the two housing portions centrally of the annular duct.
6. A flowmeter as claimed in claim 5, wherein said clamp comprises a bolt and locking nut.
7. A flowmeter as claimed in any of claims 1 to 6 wherein an arcuate recess is formed in the mating surface of one of said housing portions radially spaced from said axis of symmetry, said recess being engaged by a member projecting from the other housing portion whereby said recess determines the amount of relative rotation of the two housing portions.
8. A flowmeter as claimed in claim 7 wherein said member is integral with said other housing portion.
9. A flowmeter as claimed in any of claims 1 to 8, wherein the two housing portions are clamped between two stiffening metal plates.
10. A flowmeter as claimed in any of claims 1 to 9, wherein the fluid inlet duct opens tangentially into the annular duct.
11. A flowmeter for measuring the flow of a fluid substantially as hereinbefore described with reference to the accompanying drawings.