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US 3,992,598 AGranted
Airflow velocity switch
AssigneeAfton Incorporated
InventorsRichard Francis Welsh, Philip James Beer, Quinten La Marr Hazleton
Life of this patent
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AssigneeAfton Incorporated
InventorsRichard Francis Welsh, Philip James Beer, Quinten La Marr Hazleton
Estimating the term…
A switch assembly for sensing velocity of airflow along an airflow path and having a vane for disposition in the airflow. The vane is pivoted in a case of framework and rotational movement of the vane about the pivot axis actuates a magnetic reed switch mounted within the framework. A variety of weights are provided for attachment to the side of the vane opposite the side upon which the airflow impinges for providing a variety of unbalance torques to the vane which are counter to torque produced by airflow impingement. A consequent variety of airflow velocity switching points may be obtained. For airflow paths which are small in cross section, the pivot axis of the vane may extend parallel to the cross section and the angle through which the vane may move approaches 80.degree. from the plane of the cross section so that a minimal surface of the vane will oppose airflow through the path.
A switch sensing the flow velocity of a fluid along a vertical flow path in an upward direction comprising a vane having an upper downstream side and an upstream side exposed to the fluid flow, means for retaining said vane in horizontal disposition in the vertical flow path in the absence of flow of the fluid, means for mounting said vane for pivotal motion about a transverse axis so that the fluid flow urges said vane rotationally thereabout, a framework supporting said means for mounting, a magnetically actuated switch disposed on said framework, a magnet mounted on said vane for rotational movement therewith in and out of a position adjacent to said magnetically actuated switch, whereby said switch is actuated by a predetermined angle of rotational movement of said vane, and a predetermined mass fixedly attached to said downstream side of said vane spaced from said transverse axis, whereby airflow disruption by said predetermined mass is minimized and a predetermined torque is applied to said vane, said predetermined torque having a sense counter to that of the torque produced by the flow velocity of the fluid, the torque caused by fluid impinging against said vane at a predetermined fluid flow velocity along the flow path being greater than said predetermined torque thereby rotating said vane through said predetermined angle.
A gas flow switch indicating a predetermined gas flow velocity in one direction along an upward vertical gas flow path, comprising a framework positioned in juxtaposition with the gas flow path, pivot means mounted in said framework defining a pivot axis relative thereto, a magnetically actuated switch mounted on said framework, a vane mounted on said pivot means having opposing broad surfaces for disposition in the gas flow path, said broad surfaces being disposed on one side of said pivot axis, a magnet mounted on said vane on the other side of said pivot axis, so that said magnet moves angularly with said broad surfaces into and out of a position adjacent to said magnetically actuated switch, a weight fixedly mounted on one of said broad surfaces spaced from said pivot axis for producing a first torque for urging said vane to rotate about said pivot against the direction of the gas flow, and means for stopping said first torque from producing rotation of said vane when said broad surfaces are disposed in a substantially horizontal orientation and there is no gas flow, so that when the predetermined gas flow velocity is directed against one of said broad surfaces a second torque is produced which is greater than and counter to said first torque, whereby said magnetically actuated switch is operated by the torque derived from the predetermined gas flow velocity.
Dependencies are inferred from the claim text.