Flow Meter

Fluid flow meter incorporating magnetic detector

Flow Meter Abstract:
A device for measuring fluid volume output by a pump includes a meter housing having an inlet and an outlet through which the fluid flows. At least two inter-engaging screw spindles are rotatably mounted within the meter housing and are rotatable in response to fluid flow in an axial direction through the housing. An exciter disc is arranged in the fluid flow in the meter housing and connected to one of the at least two inter-engaging screw spindles for rotation therewith. The exciter disc has at least one substantially planar surface and a plurality of magnets circularly arranged thereon with their fields in an axial direction relative to the exciter disc. The meter housing is configured to form a gap and the exciter disc penetrates the gap, whereby a region of the meter housing is in close proximity to and extends over a portion of the planar surface of the exciter disc. At least two magnetic-sensitive detectors are disposed in the region of the meter housing proximate to and spaced from the exciter disc for cooperating with the magnets of the exciter disc for producing a signal representing rotation of the exciter disc.

Flow Meter Claims:
What is claimed is:

1. A device for measuring fluid volume, comprising:

a meter housing having an inlet and an outlet through which the fluid flows;

at least two inter-engaging screw spindles rotatably mounted within the meter housing and being rotatable in response to fluid flow in an axial direction through the housing;

an exciter disc arranged in the fluid flow in the meter housing and connected to one of the at least two inter-engaging screw spindles for rotation therewith, the exciter disc having at least one substantially planar surface and a plurality of magnets arranged thereon with their fields in an axial direction relative to the exciter disc, wherein the meter housing is configured to form a gap and the exciter disc penetrates the gap whereby a region in the meter housing accessible from outside the meter housing is in close proximity to and extends over a portion of the planar surface of the exciter disc; and

at least two magnetic-sensitive detectors disposed in said region of the meter housing proximate to and spaced from the exciter disc, for cooperating with the magnets of the exciter disc for producing a signal representing rotation of the exciter disc, wherein said at least two magnetic sensitive detectors are accessible in said region from outside the meter housing.

2. A device according to claim 1, wherein the detectors are Hall Effect sensors.

3. A device according to claim 1, wherein the meter housing has a measuring chamber through which the fluid flows, including a detector chamber, in which the detectors are disposed, with a wall proximate to the exciter disc forming the gap.

4. A device according to claim 3, wherein the meter housing includes a spindle housing section having the at least two inter-engaging spindles disposed within and a housing section mounted on the spindle housing section, the housing section enclosing the detector chamber.

5. A device according to claim 3, wherein the one spindle to which the exciter disc is connected has a spindle bearing, and further comprising:

a screen disposed in the meter housing above the spindle bearing and opposite the wall proximate the exciter disc, the screen having a central aperture through which fluid exits.

6. A device according to claim 3, wherein a flow channel in the measuring chamber in a region of the exciter disc has a cross-sectional area which is greater than or equal to the smallest cross-sectional area of the fluid flow.

7. A device according to claim 3, wherein the detector chamber contains more than two hall effect sensors.

8. A device according to claim 1, wherein the exciter disc carries magnets uniformly disposed in a circle on the disc.

9. A device according to claim 8, wherein the exciter disc carries eight (8) magnets.

10. A device according to claim 1, wherein the diameter of the exciter disc corresponds approximately to the diameter of the one inter-engaging screw spindle.

11. A device according to claim 1 wherein exciter disc is a circular disc, having a smooth surface.

12. The device according to claim 1, wherein the device constitutes a device for measuring liquid fuel in a petrol pump.

13. A method of measuring liquid fuel volume output by a petrol pump, comprising utilizing the device according to claim 1.

14. A meter for measuring fluid flow comprising:

a meter housing defining a chamber, the chamber having a fluid inlet and a fluid outlet;

two inter-engaging screw spindles within the chamber rotatably mounted between the inlet and outlet whereby fluid flows axially relative to the spindles, the spindles being arranged such that fluid flow urges the spindles to rotate;

an exciter disc within the chamber, the exciter disc comprising a plurality of magnets and being connected to one of the screw spindles; and

at least two magnetic-sensitive detectors mounted outside of the chamber in a region that extends over the exciter disc proximate to said magnets within said chamber and accessible from outside the chamber, which sensors cooperate with the magnets to detect rotation of the exciter disc.

Flow Meter Description:
What is claimed is:

1. A device for measuring fluid volume, comprising:

a meter housing having an inlet and an outlet through which the fluid flows;

at least two inter-engaging screw spindles rotatably mounted within the meter housing and being rotatable in response to fluid flow in an axial direction through the housing;

an exciter disc arranged in the fluid flow in the meter housing and connected to one of the at least two inter-engaging screw spindles for rotation therewith, the exciter disc having at least one substantially planar surface and a plurality of magnets arranged thereon with their fields in an axial direction relative to the exciter disc, wherein the meter housing is configured to form a gap and the exciter disc penetrates the gap whereby a region in the meter housing accessible from outside the meter housing is in close proximity to and extends over a portion of the planar surface of the exciter disc; and

at least two magnetic-sensitive detectors disposed in said region of the meter housing proximate to and spaced from the exciter disc, for cooperating with the magnets of the exciter disc for producing a signal representing rotation of the exciter disc, wherein said at least two magnetic sensitive detectors are accessible in said region from outside the meter housing.

2. A device according to claim 1, wherein the detectors are Hall Effect sensors.

3. A device according to claim 1, wherein the meter housing has a measuring chamber through which the fluid flows, including a detector chamber, in which the detectors are disposed, with a wall proximate to the exciter disc forming the gap.

4. A device according to claim 3, wherein the meter housing includes a spindle housing section having the at least two inter-engaging spindles disposed within and a housing section mounted on the spindle housing section, the housing section enclosing the detector chamber.

5. A device according to claim 3, wherein the one spindle to which the exciter disc is connected has a spindle bearing, and further comprising:

a screen disposed in the meter housing above the spindle bearing and opposite the wall proximate the exciter disc, the screen having a central aperture through which fluid exits.

6. A device according to claim 3, wherein a flow channel in the measuring chamber in a region of the exciter disc has a cross-sectional area which is greater than or equal to the smallest cross-sectional area of the fluid flow.

7. A device according to claim 3, wherein the detector chamber contains more than two hall effect sensors.

8. A device according to claim 1, wherein the exciter disc carries magnets uniformly disposed in a circle on the disc.

9. A device according to claim 8, wherein the exciter disc carries eight (8) magnets.

10. A device according to claim 1, wherein the diameter of the exciter disc corresponds approximately to the diameter of the one inter-engaging screw spindle.

11. A device according to claim 1 wherein exciter disc is a circular disc, having a smooth surface.

12. The device according to claim 1, wherein the device constitutes a device for measuring liquid fuel in a petrol pump.

13. A method of measuring liquid fuel volume output by a petrol pump, comprising utilizing the device according to claim 1.

14. A meter for measuring fluid flow comprising:

a meter housing defining a chamber, the chamber having a fluid inlet and a fluid outlet;

two inter-engaging screw spindles within the chamber rotatably mounted between the inlet and outlet whereby fluid flows axially relative to the spindles, the spindles being arranged such that fluid flow urges the spindles to rotate;

an exciter disc within the chamber, the exciter disc comprising a plurality of magnets and being connected to one of the screw spindles; and

at least two magnetic-sensitive detectors mounted outside of the chamber in a region that extends over the exciter disc proximate to said magnets within said chamber and accessible from outside the chamber, which sensors cooperate with the magnets to detect rotation of the exciter disc.