Measuring and testing – Volume or rate of flow – By measuring swirl rate imparted by static means
Patent
1993-01-12
1995-02-14
Goldstein, Herbert
Measuring and testing
Volume or rate of flow
By measuring swirl rate imparted by static means
7386177, G01F 110
Patent
active
053884663
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a flow meter, and in particular, to a flow meter having a helical diffuser and a rotor for measuring volumetric flow of a medium.
A flow meter of the specified type is known, for example, from European Patent Specification 0,228,577. In the case of this flow meter, there is arranged upstream of the rotor, which is disposed in a flow passage for the medium, a helical diffuser for generating a swirl in order to impinge on axially parallel extending and circumferentially bent blades of the rotor which sets the latter in rotation. Each blade of the rotor has a window designed as an axially parallel slit. A beam of a light barrier directed at right angles to the rotor spindle, passes the window. The light source of the light barrier is arranged on one side and the light receiver being arranged on the opposite side of the rotor on the housing. This principle presupposes, however, that the medium of which the flow rate is to be measured is transparent to enable transmission of the light beam of the light barrier and thus, restricts its possible applications. In addition, the number of pulses to be received per rotor revolution for the measurement when blade windows are to be passed is restricted to three, due to blade overlapping.
Whereas the known flow meter operates reliably in applications with relatively great flow rates, at low flow rates it shows that it is not capable of supplying accurate measuring results.
The present invention is therefore based on the object of providing an inexpensively producible flow meter which, on account of accurate measuring results even at the smallest rates, can be used universally.
To achieve this object, the flow meter has a substantially cylindrical housing and a rotor coaxially mounted for rotation in the housing. The rotor includes curved blades having a full surface area. A helical diffuser is disposed in a passage of the housing with the passage being coaxially upstream of the rotor. The diffuser divides a flow medium flowing through the housing into a plurality of streams and generates a swirl so as to rotate the rotor by impinging the blades. A ring member is affixed to and surrounds outer ends of the blades. A signal generator is provided which interacts with the rotor to determine a flow rate of the medium.
The use of a ring on the rotor in combination with the impingement of the curved blades on their concave side brings about an increase in the response sensitivity of the same. The cause for this is likely to be an approximately complete utilization of the kinetic energy of the flow of which the throughput is to be measured. This takes place by preventing a radial flow-off in the blade region. In this case, due to the rigid anchoring of the blades, the ring can also be used for stiffening the blades at their outer ends. This allows the blade mass to be reduced without reducing the impinged surface area. Consequently, the overall mass of the rotor does not increase due to the mass of the ring.
The ring is expediently designed in one piece together with the blades and the rotor spindle, which benefits both the stiffness and the reduction in mass. Moreover, a rotor produced in one piece allows corresponding assembly costs to be avoided. According to a preferred further development of the flow meter according to the invention, the counting or measuring signals are obtained by scanning the outer surface of the rotor ring, provided with markings. Since the flow meter consequently does not have to keep a beam path clear for a light barrier, the form of the rotor is simplified. The universal applicability of the flow meter is further increased inter alia by the fact that the medium does not have to be transparent. Apart from this, virtually any number of signals can be generated per revolution.
Further details and advantages emerge from the following description, in which an embodiment of the flow meter is described in more detail purely by way of example with reference to the drawings, in which:
FIG. 1 shows a longitudinal section through a flow
REFERENCES:
patent: 2209700 (1938-03-01), Mayo et al.
patent: 3036460 (1962-05-01), White et al.
patent: 3217539 (1961-04-01), Owen et al.
patent: 3240063 (1966-03-01), Brueckner
patent: 3307396 (1967-03-01), Griffo
patent: 3680378 (1972-08-01), Aurilio et al.
patent: 3898883 (1975-08-01), Kozak et al.
patent: 4393723 (1983-07-01), Brand
patent: 4395919 (1983-08-01), Peters
patent: 4428243 (1984-01-01), Taylor
patent: 4733570 (1988-03-01), Peters
Goldstein Herbert
Patel Harshad
LandOfFree
Flow meter does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Flow meter, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Flow meter will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-280866