A DEVICE FOR MEASURING THE RATE OF FLOW OF A FLOWING FLUID

Abstract: The device for measuring the rate of flow of a fluid flowing in a closed conduit (2) includes a rotor (5) whose speed of rotation is directly dependent on the flow rate of the fluid. The rotor (5) is carried symmetrically on a shaft (6) which extends substantially at right angles to the longitudinal axis of the conduit (2). The rotor (5) includes measuring means in the form of bores (9, 10) provided therein, and a light-conductor (11, 12) is provided for determining the rotational speed of the rotor. The rotor preferably consists of one or more mutually parallel and circular plates.

Description: A DEVICE FOR MEASURING THE RATE OF FLOW OF A FLOWING FLUID. The present invention relates to a device for measuring the rate of flow of a fluid in a closed line or con¬ duit, said device comprising a rotor which is fully surrounded by the fluid and the speed of rotation of which is directly dependent on the rate of fluid flow. The rotor of a flowmeter of this kind is carried sym- metrically by a shaft which extends substantially at right angles to the longitudinal axis of the conduit or line in which the fluid flows, and the rotor axis is asymmetric in relation to the median line of the flow field in a cross-section through the rotor shaft, so that as the fluid flows the rotor is subjected to a resultant torque and begins to rotate, and said device further including measuring means which are operative to determine the rotational speed of the rotor. Flowmeters provided with a rotor or like rotating element, for instance turbine wheels, paddle wheels or gear wheels powered by a flowing fluid are known to the art. One drawback with flowmeters of this known kind is the difficulty in manufacturing such meters, parti- cularly flowmeters provided with small bladed rotors. Furthermore, the viscosity of the fluid exerts a large retarding force which when the fluid has a high viscosity will render the flowmeter inoperative. An object of the present invention is to provide a novel flowmeter which is of considerably simpler con¬ struction than the flowmeters known hitherto and which is capable of functioning smoothly even when the fluid concerned has a very high viscosity. Accordingly, the inventive flowmeter is characterized in that the surfaces of the rotor over which the fluid flows are configured so that the torque-generating forces are the result of the friction of the fluid against said surfaces. According to one preferred embodiment of the invention, the inventive rotor comprises one or more, mutually parallel circular discs mounted on one and the same shaft, a circular cylinder or a polygonal body, for instance a four-sided plate, particularly a square plate. A perforated plate and also polygonal plates can obtain a given driving force as a result of the blade effect generated by the holes and the edges of the polygonal plates respectively. The simplicity of manufacture of an inventive rotor, particularly a rotor in the form of a planar plate, renders the flowmeter highly competitive with regard to price, in all sizes, which applies particularly to conduits or like flow-lines of large dimensions for which conventional flowmeters are manufactured in small numbers of sizes and at high tool costs. Furthermore, one and the same rotor can be used within a large volu- metric-flow area, by, for instance, modifying the diameter of the flow passage with the aid of different inserts. The invention will now be described in more detail with reference to the following drawings which illustrate preferred embodiments of an inventive flowmeter. Figure 1 is a longitudinal sectional view of a first embodi¬ ment, taken on the line I-I in Figure 2. Figure 2 is a cross-sectional view taken on the line II-II in Figure 1. Figure 3 is a longitudinal sectioned view of a second embodiment of the inventive device, and Figure 4 is a cross-sectional view taken on the line IV-IV in Figure 3. Figures 5 and 6 illustrate, in smaller scale, the flowmeter according to Figures 3 and 4 connected-up in a conduit or like flow-line. In the case of the embodiment illustrated in Figures 1 and 2, the body 1 of the flowmeter is incorporated in a conduit 2 having an inlet 3 and an outlet 4. The rotor of the flowmeter consists of a circular plate 5 which is journalled symmetrically on a shaft 6, which extends perpendicularly to the longitudinal axis of the conduit 2. The plate 5 is positioned in a space 7 in the body 1 which is asymmetric to the longitudinal axis of the conduit 2. Located at the outlet of the space 7 leading to the outlet 4 of the conduit is a flow- throttling nozzle 8. The plate 5 has two holes or bores 9 and 10 which extend parallel with the shaft 6 of said plate. These bores receive light from a light-conduc- tor, e.g. the light-conductor 11, and conduct the light to a further light-conductor, e.g. the light-conductor 12. It is thus possible to measure the speed of rota¬ tion of the plate 5 on the basis of the time which passes between those time points at which the light- conductor 12 receives the light from the light-conduc¬ tor 11. Alternatively, the speed at which the rotor or plate rotates can be measured with the aid of a light-emit- ter/light-receiver which operates with reflection on the rotor. Inductive and magnetic sensors can also be used for the purpose of measuring rotor speed. The embodiment of the flowmeter illustrated in Figures 3, 4, 5 and 6 has a rotor 13 which comprises three mutually parallel and circular plates 14 journalled on one and the same rotor shaft 15. The rotor 13 is coup¬ led so as to lie in two mutually parallel conduits 16,17 which constitute a mirror image of one another about an imaginary axis passing through the centre of the rotor 13. When fluid flows in mutually opposite directions through the conduits 16,17, as illustrated in Figures 5 and 6, the journals of the rotor 13 are relieved completely of fluid forces exerted by the rotor. In the Figure 5 illustration, the conduits 16,17 are connected in series, whereas in the Figure 6 illu¬ stration they are connected in parallel.

Claims: CLAIMS 1. A device for measuring the rate of flow of a flowing fluid in at least one closed conduit (2; 16, 17), said device comprising a rotor (5; 13) which is fully sur¬ rounded by the fluid and the speed of rotation of which is directly dependent on the flow rate of the fluid, and in which device the rotor (5; 13) is carried sym- metrically by a shaft (6; 15) which extends substan¬ tially at right angles to the longitudinal axis of the conduit (2; 16, 17), and in which measuring means (9, 10, 11, 12) are provided for determining the ; and in that the rotor surfaces over which the fluid flows are configured so that the torque-generating forces occur substantially as a result of the friction of the fluid against said surfaces. 2. A device according to Claim 1, c h a r a c - t e r i z e d in that the measuring means for deter¬ mining the rotary speed comprises at least one bore (9, 10) provided in the rotor (5) and extending parallel with said axis, said bore being operative to conduct light from one light source on one side of the rotor to a light-receiver on the other side of said rotor (5). 3. A device according to Claim 1 or 2, c h a r a c ¬ t e r i z e d in that the rotor comprises one or more mutually parallel plates (5, 14) mounted on one and the same shaft. 4. A device according to Claim 1 or 2, c h a r a c ¬ t e r i z e d in that the rotor has the form of a circular cylinder. 5. A device according to Claim 1 or 2, c h a r a c ¬ t e r i z e d in that the rotor has the form of a polygonal plate, for instance a four-sided plate, particularly a square plate. 6. A device according to any one of Claims 1-5, c h a r a c t e r i z e d in that the rotor surfaces around which the fluid flows are perforated, for in¬ stance with dense bores. 7. A device according to any one of Claims 1-5, c h a r a c t e r i z e d in that the rotor surfaces over which the fluid flows have an undulating conf¬ iguration. 8. A device according to any one of Claims 1-5, c h a r a c t e r i z e d in that the rotor surfaces over which the fluid flows are smooth. 9. A device according to Claim 1, c h a r a c ¬ t e r i z e d in that the rotor (13) is coupled so as to lie in two mutually parallel conduits (16, 17) which are the mirror image of one another around a longitu¬ dinal axis (18) passing through the centre of the rotor, whereby when fluid flows in mutually opposite directions in respective conduits (16, 17) the rotor journals will be completely relieved of load from the forces exerted by the fluid on the rotor. 10. A device according to Claim 1, c h a r a c ¬ t e r i z e d in that the rotor shaft (6) is located asymmetrically in relation to the median line of the flow field in a cross-section through the rotor shaft so that as the fluid flows the rotor (5) will obtain a resultant torque and begin to rotate.

Inventors: NOREN ANDERS, NOREN, ANDERS
Applicants: NOREN ANDERS, NOREN, ANDERS
Application year: 1989
Main classification: G01F1
IPC codes: G01F1