Electrical flow meter |
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| 申请号 | US29547972 | 申请日 | 1972-10-06 | 公开(公告)号 | US3818758A | 公开(公告)日 | 1974-06-25 |
| 申请人 | FLUID FLOW INC; | 发明人 | EASTER E; | ||||
| 摘要 | Fluid flow rate determined by measuring the displacement of distributed electrical resistance along a flow conduit through which fluid is conducted. The flow conduit is heated by current simultaneously induced therein and in a fluid storing tube of the same structural and electrical configuration. The resistances of the flow conduit and the fluid storing tube form the resistive branches of a balanced bridge circuit through which changes in the resistance distribution are measured. | ||||||
| 权利要求 | 1. In a fluid flow metering apparatus, a flow conduit made of electrically conductive material having an electrical resistance that varies as a function of temperature, means for conducting a flow of fluid through said conduit between spaced locations of common electrical potential, electrical power means for producing a flow of electrical current through said material only between said locations to heat the flow conduit and vary the resistance between said locations and measuring means connected to the conduit at a single point intermediate said locations for establishing resistive branches of a bridge circuit between said locations to measure variations in distribution of the electrical resistance along the conduit during flow of fluid therethrough. 2. The combination of 1 wherein said single point divides the total electrical resistance of the conduit material between said locations in half to form said resistive branches during substantially zero flow of the fluid. 3. The combination of claim 2 including fluid storing means structurally and electrically similar to the conduit forming a reference resistance having a substantially symmetrical distribution pattern between said locations along the conduit, said measuring means being connected to the fluid storing means at a point of symmetry relative to said resistance distribution pattern. 4. The combination of claim 3 wherein said measuring means includes current metering means connected to the conduit and the fluid storing means at said points to form balanced potential junctures, the resistances of the conduit and the fluid storing means constituting the only resistive branches of the bridge circuit. 5. The combination of claim 4 wherein said electrical power means includes a transformer in which the conduit and the fluid storing means constitute secondary loop windings extending between said spaced locations within which said current is induced. 6. The combination of claim 1 including fluid storing means structurally and electrically similar to the conduit forming a reference resIstance having a substantially symmetrical distribution pattern between said locations along the conduit, said measuring means to complete said bridge circuit being connected to the fluid storing means. 7. The combination of claim 6 wherein said measuring means includes current metering means connected to the conduit and the fluid storing means. 8. The combination of claim 7 wherein said electrical power means includes a transformer in which the conduit and the fluid storing means constitute secondary loop windings extending between said spaced locations within which said current is induced. 9. The combination of claim 6 wherein said electrical power means includes a transformer in which the conduit and the fluid storing means constitute secondary loop windings extending between said spaced locations within which said current is induced. 10. The combination of claim 1 wherein said means for conducting a flow of fluid comprises an electrically grounded heat sink body having a flow passage conducting said fluid in parallel relation to the fluid conducted through said flow conduit, said flow conduit being connected to and extending from said body at said spaced locations. 11. The combination of claim 10 including fluid storing means structurally and electrically similar to the flow conduit forming a reference resistance extending between said spaced locations on the body and to which the measuring means is connected to complete the bridge circuit, said electrical power means comprising a source of alternating current and primary winding means connected to said source and inductively coupled to said flow conduit and said fluid storing means for inducing a flow of current between said spaced locations of common potential. |
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