Catheter with flow balancing valve
A catheter has at least two irrigated ablation electrodes and a coaxial irrigation tubing to transport fluid to the electrodes by separate and dedicated flow paths. A valve is used to control flow of fluid into the coaxial irrigation tubing by means of a plunger assembly that allows fluid to flow through one lumen of the coaxial irrigation tubing while regulating the flow into the other lumen of the coaxial irrigation tubing in response to the fluid flow rate and pressure applied to the plunger assembly.
1 . A valve for use with a catheter irrigation tubing, comprising:
a body defining an inlet opening, an outlet opening and an interior cavity connecting the inlet opening and the outlet opening, the inlet opening adapted to receive fluid flow at a selected flow rate;
a plunger assembly situated in the interior cavity, the plunger assembly having:
a plunger head;
a base comprising one or more openings through which fluid can pass;
a spring member supporting the plunger head from the base at a predetermined position relative to the inlet opening; and
a first lumen passing through the plunger head and the base,
the body defining first and second fluid flow paths, the first fluid flow path including the first lumen and excluding the interior cavity, and the second fluid flow path including the interior cavity and excluding the first lumen, the first fluid flow path receiving a first portion of a flow entering the valve via the inlet opening, the second fluid flow path receiving a second portion of the flow entering the valve via the inlet opening,
the spring member being configured to allow displacement of the plunger head relative to the inlet opening when the flow rate exceeds a threshold flow rate to vary at least one of the first and second portions of the flow received by the first and second fluid flow paths.
2 . The valve of claim 1 , wherein the body comprises:
a proximal body portion housing the plunger head and comprising the inlet opening and one or more inlet transitional regions having decreased cross-sectional area compared to the interior cavity; and
a distal body portion housing the base and comprising the outlet opening and one or more outlet transitional regions having decreased cross-sectional area compared to the interior cavity.
3 . The valve of claim 2 , wherein a size or shape of the one or more inlet transitional regions does not exactly correspond to a size and shape of the plunger head.
4 . The valve of claim 1 , wherein the plunger head comprises a proximal surface having one or more channels or grooves.
5 . The valve of claim 2 , wherein the base is fixedly positioned in the distal body portion.
6 . The valve of claim 5 , wherein the base is wedged against a flange in the distal body portion.
7 . The valve of claim 1 , wherein the plunger head is generally conical, spherical or planar in shape.
8 . The valve of claim 2 , wherein the plunger head has a generally convex profile and the one or more inlet transitional regions has a generally concave profile.
9 . The valve of claim 8 , wherein the convex profile of the plunger head and the concave profile of the one or more inlet transitional regions do not exactly correspond.
10 . The valve of claim 1 , wherein displacement of the plunger head farther from the inlet opening increases the flow received by the second fluid flow path.
11 . The valve of claim 1 , wherein displacement of the plunger head closer to the inlet opening decreases the flow received by the second fluid flow path.
12 . The valve of claim 1 , further comprising an outer lumen that surrounds a portion of the first lumen extending through the outlet opening.
13 . The valve of claim 1 , wherein the first fluid flow path includes the inlet opening and the first lumen.
14 . The valve of claim 1 , wherein the second fluid flow path includes the inlet opening, the interior cavity past the plunger head and the base, and the outlet opening.
15 . The valve of claim 1 , wherein the body has a longitudinal axis and the inlet opening and the outlet opening are generally aligned with the longitudinal axis.
16 . The valve of claim 1 , wherein the body has a longitudinal axis, and the first lumen is generally aligned with the longitudinal axis.
17 . The valve of claim 1 , wherein the spring member is a coil spring.
18 . The valve of claim 1 , wherein the spring member extends between the plunger head and the base.
19 . The valve of claim 1 , wherein the inlet opening and the outlet opening define a flow direction through the valve and the plunger head is upstream of the base in relation to the flow direction.