HUMIDIFICATION

• US 3,638,926 A
• Filed: 09/26/1968
• Issued: 02/01/1972
• Est. Priority Date: 09/27/1967
• Status: Expired due to Term

• Current Assignee: Fisher & Paykel Limited (Haier Group Company)
• Original Assignee: Alfred W. Melville, David H O'Hare, Frank W. Shacklock
• Inventors: Melville, Alfred W., Shacklock, Frank W., O'Hare, David H.
• Primary Examiner(s): Miles, Tim R.
• Application Number:
  US04/762,683
• Time in Patent Office: 1,223 Days
• Field of Search: 128/192,193,212,1B 219/274,301,307 261/139,142,130,154,153,DIG.34,DIG.65
• US Class Current: 261/130
• CPC Class Codes: A61M 16/16 Devices to humidify the respiration air A61M16/1045 takes precedence
• CPC Class Codes: F24F 6/04 using stationary unheated wet elements
• CPC Class Codes: F24H 1/00 Water heaters, e.g. boilers, continuous-flow heaters or water-storage heaters steam boilers F22B
• CPC Class Codes: Y10S 261/34 Automatic humidity regulation

Abstract

Humidification and heating apparatus preferably including a spirally wound resistance-heated plate with its axis vertical and one side in thermal contact with a sheet of water absorbent material. Both plate and material are partially immersed in water in a tank the lid of which is sealingly engaged with the spiral plate. When used for artificial respiration air from a respirator is admitted and discharged from the tank at points such that it must travel along the spiral passage formed by the plate, water surface and lid thus picking up heat and water vapor to emerge preferably substantially saturated at a temperature which does not exceed the maximum desired input temperature at the patient. To prevent condensation en route to the end user, sufficient further heat is imparted to balance that lost in passage. Preferably the interconnecting apparatus between the humidifier and patient is heated at least in portions along its length and preferably by electrically heated elements embedded in the wall of the usual flexible tube leading from the humidifier to the patient.

Claims

1. Apparatus for humidifying and heating air to be breathed by a patient undergoing artificial respiration, comprising humidification and heating means to heat air to a suitable temperature which does not exceed, under steady operating conditions, the maximum desired temperature at which the air is desired to be admitted into the patient'"'"''"'"'s body, and to substantially saturate the air with water vapor at that output temperature;

and further heating means to further heat the substantially saturated air from said output temperature, the air heated by said further heating means being carried in use through auxiliary apparatus into the patient'"'"''"'"'s body, the construction and arrangement being such that in use the increase in temperature of the air to be breathed which is imparted by said further heating means at the output thereof is selected to be equal to or to exceed the temperature drop which occurs in the air so heated in its passage between said output of said further heating means and the patient'"'"''"'"'s body and in any event said temperature increase is adJusted to insure that the air is delivered to the patient at no more than said maximum desired temperature;

said air humidifier and heater comprising a body portion forming a water container adapted to be pressurized and including sealable water inlet means to enable water to be introduced from time to time in use;

a water heater to heat water placed in said water container in use;

a heat conductive plate arranged as a spiral coil with suitably spaced turns and located within said water container;

a water absorbent material disposed along the spiral passage formed by said heat conductive plate;

firs and second air passages through said body portion communicating with the interior of said body portion, at least the entrance of the outlet air passage being above water level and one of said air passages communicating with the outside core, and the other with the inside core, of said spiral passage, said water absorbent material being partially immersed in water, said spirally coiled heat conductive plate arranged with its axis substantially vertical in use and also being partially immersed in said water to provide a lower seal to said spiral passage, the top of said spirally coiled heat conductive plate being substantially in sealing engagement with said body portion so that air passing in whichever of said first or second air passages is the inlet passage can only leave via the other air passage and after passing through said spiral passage during which it gains an increased heat and water vapor content.

2. Apparatus as claimed in claim 1 wherein the exit of said air inlet passage is above water level.

3. Apparatus as claimed in claim 1 wherein said humidifier and heater effects at least 85 percent saturation of the air passing through it at a volume flow of 30 liters per minute.

4. Apparatus as claimed in claim 1 which includes air temperature control means to monitor and control the temperature of the air leaving the humidifier and heater.

5. Apparatus as claimed in claim 4 in which the humidification and heating means include control means to ensure that the air supplied therefrom does not exceed a temperature of blood heat.

6. Apparatus as claimed in claim 1 wherein said body portion is in two parts one of which comprises a water tank and the other a lid therefor, both being normally in sealing engagement but being demountable when desired.

7. Apparatus as claimed in claim 6 wherein said sealable water inlet is comprised by providing said body portion in said two parts.

8. Apparatus as claimed in claim 6 wherein a sealable hole is provided through said water container to enable water to be added to said apparatus.

9. Apparatus as claimed in claim 1 wherein said water absorbent material is in contact with said heat conductive plate.

10. Apparatus as claimed in claim 9 wherein said water absorbent material is paper.

11. Apparatus as claimed in claim 10 wherein said water heater is comprised by said heat conductive plate.

12. Apparatus as claimed in claim 11 wherein said heat conductive plate is in thermal contact with an electrical heating element.

13. Apparatus as claimed in claim 12 wherein said heat conductive plate is a metal plate having pressed out tabs securing to it, in a suitable disposition, a suitable length of insulated electric heating element wire.

14. Apparatus as claimed in claim 12 wherein said heat conductive plate is itself electrically conducting and is heated by passage of current directly through it.

15. Apparatus as claimed in claim 14 wherein said heat conductive plate is made of stainless steel.