Flow sensor probes

• US 4,399,696 A
• Filed: 12/11/1980
• Issued: 08/23/1983
• Est. Priority Date: 04/19/1979
• Status: Expired due to Term

• Current Assignee: C/. Goodman Natalie Liebman, Model Screw Products Incorporated
• Original Assignee: Wilgood Corporation
• Inventors: Feller, Murray F.
• Primary Examiner(s): Goldstein, Herbert
• Application Number:
  US06/215,524
• Time in Patent Office: 985 Days
• Field of Search: 73/195, 73/861.77, 73/861.79, 73/861.89, 73/861.92
• US Class Current: 73/195
• CPC Class Codes: G01F 1/10 using rotating vanes with axial admission
• CPC Class Codes: G01F 1/115 with magnetic or electromagnetic coupling to the indicating device

Abstract

The disclosed flow sensors involve rotor-bearing probes proportioned for entry through a hole in a pipe. By omitting flow-straightening vanes, the rotors can be relatively large. Multiple rotors distributed across the flow passage, especially one or more pairs of oppositely rotating rotors, have respective rotation sensors whose outputs are combined for averaging out the varied effects of the flow on the rotors. The rotation sensors produce trains of pulses that are converted to narrow spikes before being combined.

Claims

1. A flow sensor, including a conduit, at least one pair of independently rotatable multiple-blade rotors mounted in the conduit for independent rotation about parallel axes displaced equally from the axis of the conduit, the blades of any pair of rotors being arranged to cause mutually opposite directions of flow-activated rotation of the rotors about the axes thereof, and rotation sensors adjacent said rotors, respectively.

2. A flow sensor as in claim 1, wherein each of said rotors is of the type whose axis is disposed along the flow path, said flow sensor being at least largely free of flow-straightening means for said rotors.

3. A flow sensor as in claim 2 wherein the axes of said pair of rotors are displaced symmetrically from the axis of the conduit.

4. A flow sensor as in claim 1, wherein said one pair of rotors forms part of a probe that includes a support for the rotors and the rotation sensors thereof, and means for mounting the probe as a closure for the hole in the wall of the conduit, the rotors being small enough to be inserted into the conduit through said hole yet so large as to exclude significant flow-straightening means from the probe.

5. A flow sensor as in claim 1, wherein said rotors have elements that sweep past said rotation sensors, respectively, to produce a train of pulses for each of said rotors and means for combining said trains of pulses.

6. A flow sensor as in claim 1 wherein said rotors have elements that sweep past said rotation sensors, respectively, to produce a train of pulses for each of said rotors, means for combining said trains of pulses, and means interposed between the rotation sensor of each said rotor and said combining means for sharply reducing the duration of the pulses from the sensor of each said rotor.

7. A flow sensor as in claim 1 wherein the conduit has a hole in the wall thereof through which a said rotor is admitted into the conduit, further including mounting means for each said rotor including a closure for said hole, each said rotor at least approaching the maximum size as limited by the hole through which it is admitted into the conduit, said flow sensor being free of significant flow-straightening means endwise of the rotors.

8. Flow-sensing means including a probe comprising a rotor having blades of high resistivity compared to the resistivity of the fluid whose flow is to be sensed, two elongated parallel metal members carrying bearings for said rotor, at least one insulating end support united to an end of each of said metal members, a rotation-sensing electrode carried by said end support adjacent the paths of the blades of said rotor, the blades of the rotor being arranged to effect predominating electric coupling between said sensing electrode and alternate ones of said metal members, and external electrical connection means extending to said elongated metal members and said sensing electrode.

9. Flow-sensing means as in claim 8, further including a second rotor having bearings carried by said elongated parallel metal members so that said rotors have parallel axes, a second support of insulation for the ends of said elongated metal members opposite to the ends thereof supported by said one end support, whereby said end supports and said elongated metal members constitute a frame supporting said rotors, and a second rotation-sensing electrode carried by said second support adjacent the paths of the blades of said second rotor, and an external electrical connection extending to said second rotation-sensing second electrode.

10. Flow-sensing means as in claim 9, including alternating excitation means having opposite-phase connections to said elongated metal members and a detector connected to each of said rotation sensing electrodes.

11. Flow-sensing apparatus, including a conduit, a probe having an elongated support and a means for mounting the probe on the wall of the conduit with the elongated support extending transverse to the flow of fluid therein, said probe comprising plural multiple-blade turbine-type rotors concurrently exposed to the flow of fluid and mounted on the support for independent flow-responsive rotation about parallel axes transverse to the length of the support and adapted to be disposed along the flow path and spaced apart along the support, said rotors being admissible into the conduit through a hole in the wall thereof, the hole being sealed by a portion of said mounting means, each said rotor including the blades thereof at least approaching the maximum size admissible into the conduit through said hole, said flow-sensing apparatus being free of significant flow straightening means endwise of the rotors, rotation sensing means for said rotors, respectively, and means for combining the outputs of said sensing means as a representation of the flow in the conduit.

12. A flow sensor, including a cylindrical conduit, plural independently rotatable multiple-blade rotors mounted in the conduit for rotation about axes parallel to each other and to the axis of the conduit, at least a pair of said rotors being arranged for concurrent flow-activated rotation in mutually opposite directions, a sensor adjacent each of said rotors, respectively, for providing output signals representing rotor rotation, and means for deriving from said sensors a combined representation of the flow.

13. A flow sensor as in claim 12, further including an elongated support extending transversely in said conduit, said pair of rotors being mounted on said common support.

14. A flow sensor as in claim 13 wherein the axes of said pair of rotors are displaced equally from the conduit axis.

15. A flow sensor as in claim 12 wherein said plural rotors are installed at least at two locations mutually displaced along the flow path.

16. A flow sensor as in claim 12 wherein the axes of said pair rotors are displaced equally from the conduit axis.

17. A flow sensor as in any of claims 12-16 wherein the rotors of said pair of rotors are dimensioned alike except that the blades thereof slope oppositely in relation to the flow path for causing the aforesaid rotation of the rotors in mutually opposite directions.

18. A flow sensor as in any of claims 12-16 wherein said rotors have mounting means, wherein said conduit has at least one hole for entry of the rotors and their mounting means into the conduit, and wherein each of said multiple-blade rotors including the blades thereof at least approaches the maximum size admissible through the hole at which it enters the conduit.