Catheter fluid-velocity flow probe
AssigneeMillar Instruments, Inc.
InventorHuntly D. Millar
Life of this patent
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Abstract
A catheter fluid-velocity flow probe is disclosed which has greater sensitivity and which dissipates less heat during operation than flow probes heretofore constructed. These significant results are achieved by providing two electromagnets in the probe to generate two separate magnetic fields. Each electrode is positioned between the poles of an electromagnet in the region of highest magnetic flux density of each electromagnet. The electromagnets are reduced in size, and a tubing may be inserted in the central portion of the probe during construction. This tubing permits the attachment of additional measuring devices to the distal end of the probe to permit multiple measurements in a fluid to be made simultaneously.
Claims32
A fluid-velocity flow probe for insertion into a vessel carrying conductive fluid in a subject, which probe is suitable for attachment to the distal end of a catheter, which probe develops a voltage which is proportional to the velocity of the conductive fluid passing the probe, and which prope comprises:
- a housing;
- means for attaching the housing to a catheter;
- two electromagnets disposed in the housing of the probe for generating two separate magnetic fields, which electromagnets have ferromagnetic cores with gaps between poles;
- two electrodes located in the housing with outer surfaces for fluid-electrode interface, said outer surfaces being exposed to the conductive fluid, each electrode being disposed such that the exposed outer surface for the fluid-electrode interface is substantially in the gap between the poles of the respective electromagnets;
- electrical conductors associated with said electromagnets and electrodes;
- electrically insulating bonding material encapsulating the electromagnets and forming the housing, the bonding material being formed to permit exposure of the outer surfaces of the electrodes so that conductive fluid flowing past the probe will come in direct contact with the electrodes.
A fluid-velocity flow probe for attachment to a catheter and for insertion into a vessel carrying conductive fluid, comprising:
- an elongated housing having a pair of indentations formed on substantially opposite sides of the exterior of the housing;
- means for attaching the housing to a catheter;
- a pair of electromagnets located in the housing for generating separate magnetic fields in each of the indentations with magnetic flux in a direction generally perpendicular to the longitudinal axis of the housing, the electromagnets providing magnetic flux in each indentation in the same direction when voltage is applied;
- an electrode associated with each electromagnet and disposed in each of the indentations with the outer surface of each electrode exposed to form a fluid-electrode interface between the electrodes and the conductive fluid in the region substantially between the poles of each
- elect romagnet;
- electrical conductors associated with each of said electromagnets and electrodes;
- and
- an insulating material encapsulating the electromagnets, which forms the housing, and supporting the electrodes.
A fluid-velocity flow probe for insertion into a vessel carrying conductive fluid in a subject, which probe is suitable for attachment to the distal end of a catheter, which catheter comprises a central lumen and electrical conductors between its proximal and distal ends, which probe develops a voltage which is proportional to the velocity of the conductive fluid passing the probe, and which probe comprises:
- a housing;
- means for attaching said housing to a catheter;
- two electromagnets disposed in the housing of the probe for generating two separate magnetic fields, wherein each electromagnet comprises a ferromagnetic core with gaps between poles and windings having a start and a stop winding, said windings being wound on each ferromagnetic core in the same manner between the start and stop windings, and wherein electrical continuity is provided between the stop winding on the first ferromagnetic core and the start winding on the second magnetic core;
- a center-tap conductor electrically connected to the point of electrical continuity between the stop winding on the first ferromagnetic core and the start winding on the second ferromagnetic core;
- two electrodes located in the housing with outer surfaces for fluid-electrode interface, said outer surfaces being exposed to the conductive fluid, each electrode being associated with an electromagnet and being disposed such that the exposed outer surface for the fluid-electrode interface is substantially in the gap between the poles of the electromagnet;
- means for electrically connecting one conductor in the catheter to the start winding on the first ferromagnetic core, for connecting a second conductor in the catheter to the stop winding on the second ferromagnetic core, and for connecting a third conductor in the catheter to be center-tap conductor;
- means for connecting the electrodes to a fourth and a fifth conductor in the catheter;
- and
- electrically insulating bonding material encapsulating the electromagnets and forming the housing of the probe, the bonding material being formed to permit exposure of the outer surfaces of the electrodes to the conductive fluid so that conductive fluid flowing past the probe will come in direct contact with the electrodes.
Dependencies are inferred from the claim text.