Heating element for liquid warming device

• US 20060086361A1
• Filed: 08/23/2005
• Published: 04/27/2006
• Est. Priority Date: 08/24/2004
• Status: Active Grant

• Current Assignee: C Change Surgical LLC
• Original Assignee: C Change Surgical LLC
• Inventors: Kammer, Patrick, Rackers, Kevin Joseph
• Granted Patent: US 7,560,667 B2
• Time in Patent Office: Days
• US Class Current: 128/849
• CPC Class Codes: A61B 46/10 specially adapted for instruments, e.g. microscopes
• CPC Class Codes: A61M 3/0245 Containers therefor, e.g. with heating means or with storage means for cannula
• CPC Class Codes: A61M 5/44 having means for cooling or heating the devices or media

Abstract

This disclosure provides examples of innovations for a heating pad to be used with heating removable basins or drapes containing sterile fluid. When used with a sterile basin, it is desirable for the pad to deform to conform to the irregular surface on the bottom of the basin. It is also desirable for the pad to have a low thermal mass so that the pad is more responsive to the control system.

Claims

1. A pad for heating a fluid in a basin, the pad comprising:

a set of at least one imbedded resistive heater located inside the pad;

a top of the pad located above the at least one imbedded resistive heater and intended to support a basin containing fluid in the basin so that the fluid in the basin can be heated;

a bottom of the pad located below the at least one imbedded resistive heater;

a rim around the perimeter of the pad; and

a set of protrusions extending downward from the bottom of the pad for contacting a surface of a liquid warming device.

2. The pad of claim 1 wherein the top of the pad and the bottom of the pad are made from the same material and the top of the pad had been fused to the bottom of the pad to imbed the set of at least one imbedded resistive heater between the top of the pad and the bottom of the pad.

3. The pad of claim 1 wherein the top of the pad and the bottom are made from thermal insulators and the thickness of the top of the pad is less than half the thickness of the bottom of the pad such that the bottom of the pad insulates the heater more than the top of the pad insulates the heater so that more heat leaves the pad through the top of the pad than through the bottom of the pad.

4. The pad of claim 1 wherein the protrusions are adapted to deform to facilitate the movement of the top of the pad to conform to the shape of a basin bottom for the basin containing fluid located on the top of the pad.

5. The pad of claim 4 wherein the protrusions are conical frustums.

6. The pad of claim 4 wherein the height of the outer rim is less than the combined height of a protrusion, the bottom of the pad above the protrusion, the portion of the at least one heater above the bottom of the pad, and the top of the pad above the portion of the at least one heater such that the pad is supported by the contact of the protrusions on the surface of the liquid warming device.

7. The pad of claim 1 wherein the protrusions are comprised of a thermal insulator.

8. The pad of claim 1 further comprising a heat distribution layer adjacent to the at set of at least one imbedded resistive heater, the heat distribution layer serving to move heat from the set of at least one imbedded heater towards the rim of the pad.

9. The pad of claim 8 wherein the heat distribution layer comprises fingers to move heat towards the rim of the pad.

10. A pad for heating a fluid in a basin, the pad comprising:

an inside face designed to make contact with basin;

an outside face with a set of protrusions extending outward from the outside face of the pad for contacting a surface of a liquid warming device; and

a set of at least one imbedded resistive heater located within the pad between the inside face and the outside face of the pad, the set of at least one imbedded resistive heater located within the pad closer to the inside face of the pad than to the outside face of the pad.

11. A method of heating fluid in a removable basin, the basin comprising an inside and an outside and a rim extending out essentially horizontally from the top of the inside of the basin, with the inside adapted to contain water, the outside having a bottom, the method comprising:

placing the bottom of the basin on a pad in a liquid warming device, the basin encircled by a drape such that the bottom of the basin contacts the pad and not the drape and the drape extends outward from the basin beyond the rim of the basin to cover at least a portion of the liquid warming device;

adding fluid to the basin; and

applying heat from a heater in the pad through the top of the pad which has substantially conformed to the shape of the bottom of the basin.

12. The method of claim 11 wherein further comprising the step of deforming a set of protrusions extending from a bottom of the pad to deform the pad to assist the top of the pad in substantially conforming to the shape of the bottom of the basin.

13. The method of claim 11 wherein the step of placing the bottom of the basin encircled by the drape on the pad in the liquid warming device further comprises the step of positioning a drape with a hole in the drape to place the hole over a cavity in the liquid warming device, the cavity containing the pad such that the basin is placed on the pad by placing the bottom of the basin through the hole in the drape.

14. The method of claim 11 wherein the step of placing the bottom of the basin encircled by the drape on the pad in the liquid warming device further comprises the step of bonding the drape to the exterior of the basin below the top face of the rim and above the bottom of the basin such that the bottom of the basin with the bonded drape is placed in a cavity in the liquid warming device containing the pad.

15. A liquid warming device comprising:

a sterile drape in a cavity of the liquid warming device, a portion of the drape extending out beyond the cavity to cover at least a portion of the liquid warming device to separate the covered portion of the liquid warming device from a sterile field;

another portion of the drape resting on a pad, the pad comprising;

a first layer of pliable thermally insulative material above a set of at least one heating unit which is above a second layer of pliable thermally insulative material, at least twice as thick as the first layer such that more heat leaves the pad through top of the first layer than through the bottom of the second layer;

such that the drape is partially protected from mechanical damage from a dropped item dropped into the draped cavity as the pad will deform upon impact from a dropped item onto the draped pad.

16. The liquid warming device of 15 wherein the pad further comprises a set of protrusions extending downward from the second layer of pliable thermally insulative material such that a portion of the deformation of the pad upon impact from a dropped item comes from deformation of at least one of the set of protrusions.