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A fluid flow detection device includes a housing of non-magnetic metal, a flow passage through the housing and a valve seat in the flow passage. A magnetic valve element emits a magnetic field. The valve element is movable relative to the valve seat between a closed position blocking fluid flow thro

A fluid flow detection device includes a housing of non-magnetic metal, a flow passage through the housing and a valve seat in the flow passage. A magnetic valve element emits a magnetic field. The valve element is movable relative to the valve seat between a closed position blocking fluid flow through the flow passage and an open position allowing fluid flow through the flow passage. The magnetic valve element is biased toward the closed position. A magnetic field enhancer is movable with the magnetic valve element for enhancing the magnetic field. A magnetic field sensor on the housing is operable to signal a change in position of the valve element as it moves between its open and closed positions.

대표청구항 ▼

1. A fluid flow detection device, comprising a housing of non-magnetic metal,a flow passage through the housing,a valve seat in the flow passage,a magnetic valve element comprising a magnetized metal ball valve emitting a magnetic field, said valve element being movable relative to the valve seat be

1. A fluid flow detection device, comprising a housing of non-magnetic metal,a flow passage through the housing,a valve seat in the flow passage,a magnetic valve element comprising a magnetized metal ball valve emitting a magnetic field, said valve element being movable relative to the valve seat between a closed position blocking fluid flow through the flow passage and an open position allowing fluid flow through the flow passage, said magnetic valve element being biased toward said closed position,a magnetic field enhancer movable with the magnetic valve element for enhancing said magnetic field, anda magnetic field sensor on the housing operable to signal a change in position of the valve element as it moves between its open and closed positions. 2. A fluid flow detection device as set forth in claim 1 wherein the valve element is sized to move from its closed position toward its open position a distance sufficient to be sensed by said magnetic field sensor in response to a fluid flow volume as small as 0.0015 cubic inch. 3. A fluid flow detection device as set forth in claim 1 wherein the magnetized metal ball valve having a diameter in a range from about 0.125 inch to about 0.25 inch. 4. A fluid flow detection device as set forth in claim 3 wherein the metal ball valve has a diameter in a range from about 0.125 inch to about 0.188 inch. 5. A fluid flow detection device as set forth in claim 3 wherein said flow passage has a relatively narrow section immediately downstream from the valve seat and a wider section downstream from the first narrow section at a position aligned with the valve element when the element is in the open position, said wider section having a diameter greater than the diameter of the metal ball. 6. A fluid flow detection device as set forth in claim 3 wherein the magnetic field enhancer is downstream from the ball valve. 7. A fluid flow detection device as set forth in claim 6 wherein the magnetic field enhancer comprises a metal plunger extending longitudinally with respect to the flow passage. 8. A fluid flow detection device as set forth in claim 7 further comprising a spring engaging to plunger for biasing the plunger and ball valve toward said valve seat. 9. A fluid flow detection device as set forth in claim 8 further comprising a device for adjusting the biasing force exerted by the spring. 10. A fluid flow detection device as set forth in claim 7 wherein the magnetic field sensor is a solid-state sensor. 11. A fluid flow detection device as set forth in claim 10 wherein the solid-state sensor comprises a body and a sensing face adjacent a front end of the body, the front end of the body being mounted in a recess in the housing configured to reduce the distance between the sensing face and the magnetic valve element. 12. A fluid flow detection device as set forth in claim 11 wherein the recess comprises a bore extending generally at right angles to a centerline of the fluid flow passage. 13. A fluid flow detection device as set forth in claim 1 wherein the flow passage has an inlet end configured for receiving a lubricant feed line. 14. A fluid flow detection device as set forth in claim 13 wherein the lubricant comprises grease or oil. 15. A fluid flow detection device as set forth in claim 1 wherein the housing comprises brass, aluminum, or stainless steel. 16. A fluid flow detection device as set forth in claim 1 installed in a lubricant delivery system comprising a lubricant distributor for delivering metered volumes of lubricant to a lubrication site at intermittent intervals, said flow passage in the non-magnetic housing having an inlet in communication with the lubricant distributor and an outlet in communication with the lubrication site. 17. A lubricant delivery system, comprising: a lubricant delivery device for delivering lubricant to a lubrication site at intermittent intervals;a flow detection device comprising a non-magnetic metal housing, a flow passage through the housing having an inlet in communication with the lubricant delivery device and an outlet in communication with the lubrication site, a valve seat in the flow passage, a magnetic valve element comprising a magnetized metal ball valve movable relative to the valve seat between a closed position blocking fluid flow through the flow passage and an open position allowing fluid flow through the flow passage, said magnetic valve element being biased toward said closed position, a magnetic field enhancer movable with the magnetic valve element for enhancing the magnetic field adjacent the magnetic valve element, and a magnetic field sensor on the housing operable to signal a change in position of the valve element as it moves between its open and closed positions; anda controller for controlling operation of the lubricant delivery device and receiving signals from the magnetic field sensor. 18. A lubricant flow detection device as set forth in claim 17 wherein the valve element is sized to move from its closed position toward its open position a distance sufficient to be sensed by said magnetic field sensor in response to a fluid flow volume as small as 0.0015 cubic inch. 19. A fluid flow detection device as set forth in claim 18 wherein the magnetized metal ball valve having a diameter in a range of about 0.125 inch to about 0.25 inch. 20. A fluid flow detection device as set forth in claim 19 wherein the magnetic field enhancer comprises a metal plunger extending longitudinally of the flow passage downstream from the ball valve.