Infusion fluid warmer
The present invention relates in one aspect to an infusion fluid warmer which comprises a casing shell having an upper wall structure and a lower, opposing, wall structure. The casing shell encloses a fluid channel or passage extending through the casing shell in-between the upper and lower wall structures and fluid inlet and outlet ports coupled to opposite ends of the fluid channel or passage to allow a flow of infusion fluid through the casing shell. A housing shell is formed in a thermally conducting and electrically insulating material and a heating element is bonded to the housing shell and thermally coupled thereto. The fluid channel or passage extends through the housing shell or extends around the housing shell such that heat energy is transferred to the infusion fluid by direct physical contact with housing shell material.
1. An infusion fluid warmer comprising:
a casing shell having an upper wall structure and an opposing lower wall structure;
a fluid channel disposed within and extending through the casing shell;
fluid inlet and outlet ports coupled to opposite ends of the fluid channel to allow a flow of infusion fluid through the casing shell;
a housing shell comprising a plate shaped upper wall structure and an opposing plate shaped lower wall structure disposed within the casing shell, the housing shell formed of a thermally conducting and electrically insulating material;
an electrical resistor having a resistance, wherein the electrical resistor is bonded to and thermally coupled to the housing shell;
an aluminum heat exchanger thermally coupled to and sandwiched between the plate shaped upper wall structure and the opposing plate shaped lower wall structure;
wherein the fluid channel extends through the aluminum heat exchanger such that heat energy is transferred to the infusion fluid by direct physical contact with the aluminum heat exchanger,
wherein the electrical resistor acts as a first heating element delivering heat to warm the infusion fluid in the fluid channel and acts as a temperature sensor sensing a temperature of the infusion fluid in the fluid channel; and
a controller circuit operatively coupled to the electrical resistor,
wherein the controller circuit is configured to control an amount of power being delivered by the electrical resistor into the infusion fluid, based on a desired or target temperature of the infusion fluid and a temperature of the infusion fluid as sensed by the electrical resistor.
2. The infusion fluid warmer according to claim 1 , wherein the electrical resistor is bonded to a surface of the plate shaped upper wall structure facing away from a straight portion of the fluid channel and a second heating element is bonded to a surface of the plate shaped lower wall structure facing away from the fluid channel.
3. The infusion fluid warmer according to claim 2 , wherein at least one surface of the plate shaped upper and lower wall structures facing away from the fluid channel comprises a pair of electrical coupling terminals for receipt of electrical power to the electrical resistor or the second heating element.
4. The infusion fluid warmer according to claim 1 , wherein the plate shaped upper wall structure of the housing shell has a height less than 1.0 cm or the plate shaped lower wall structure has a height less than 1.0 cm.
5. The infusion fluid warmer according to claim 1 , wherein a height of the fluid channel is between 0.1 mm and 5 cm.
6. The infusion fluid warmer according to claim 1 , wherein the fluid channel comprises a straight portion possessing a rectangular cross-sectional profile.
7. The infusion fluid warmer according to claim 1 , wherein the housing shell comprises a ceramic material.
8. The infusion fluid warmer according to claim 7 , wherein the ceramic material is selected from the group consisting of Aluminum Oxide, Aluminum Nitrate and Beryllium Oxide.
9. The infusion fluid warmer according to claim 1 , wherein the resistor comprises a thick film or thin film resistor.
10. The infusion fluid warmer according to claim 1 , wherein the casing shell forms at least a portion of the fluid channel.
11. The infusion fluid warmer according to claim 10 , wherein the portion of the fluid channel is disposed between the housing shell and an opening of the casing shell.
12. The infusion fluid warmer according to claim 1 , wherein the infusion fluid is a liquid.
13. An infusion fluid warmer comprising:
a casing shell having an upper wall structure and an opposing lower wall structure;
a fluid channel disposed within and extending through the casing shell;
fluid inlet and outlet ports coupled to opposite ends of the fluid channel to allow a flow of infusion fluid through the casing shell;
a housing shell comprising a plate shaped upper wall structure and an opposing plate shaped lower wall structure disposed within the casing shell, the housing shell formed of a thermally conducting and electrically insulating material;
a first heating element comprising a resistor having a resistance bonded to and thermally coupled to the housing shell;
an aluminum heat exchanger thermally coupled to and sandwiched between the plate shaped upper wall structure and the opposing plate shaped lower wall structure;
wherein the fluid channel extends through the aluminum heat exchanger such that heat energy is transferred to the infusion fluid by direct physical contact with the aluminum heat exchanger; and
a temperature sensor comprising the resistor of the first heating element, the temperature sensor configured for determining a temperature of the infusion fluid in the fluid channel,
a controller circuit operatively coupled to the temperature sensor and to the first heating element to control instantaneous power dissipation of the first heating element, the controller circuit configured to adjust power dissipation in the first heating element in accordance with a desired or target temperature of the infusion fluid based on temperature data from the temperature sensor,
wherein the casing shell forms at least a portion of the fluid channel.
14. The infusion fluid warmer according to claim 13 , wherein the portion of the fluid channel is disposed between the housing shell and an opening of the casing shell.