Evaporative humidifier

• US 4,225,542 A
• Filed: 12/12/1978
• Issued: 09/30/1980
• Est. Priority Date: 12/12/1978
• Status: Expired due to Term

• Current Assignee: 3M Company
• Original Assignee: 3M Company
• Inventors: Wall, Thomas H., Johnson, Kevin T.
• Primary Examiner(s): Chiesa, Richard L.
• Application Number:
  US05/968,829
• Time in Patent Office: 658 Days
• Field of Search: 261/70, 261/104, 261/107, 261/131, 261/142, 261/153, 261/154, 261/DIG. 65, 128/186, 128/188, 128/192-194, 219/271-276, 219/306, 219/307, 219/311, 219/362
• US Class Current: 261/142
• CPC Class Codes: A61M 16/1075 by influencing the temperature A61M16/1045 takes precedence
• CPC Class Codes: A61M 16/109 the humidifying liquid or the beneficial agent
• CPC Class Codes: A61M 16/167 acting vertically on the valve
• CPC Class Codes: A61M 2205/3368 Temperature
• CPC Class Codes: A61M 2205/3653 by Joule effect, i.e. electric resistance
• CPC Class Codes: Y10S 261/65 Vaporizers

Abstract

A sterilizable evaporative humidifier for respiratory usage having a disposable absorbent evaporative element is disclosed. The humidifier provides humidification, low pressure drop and a very short warm-up period. Electronic controls are provided to ensure safe automatic operation.

Claims

1. A sterilizable evaporative humidifier comprising a humidification chamber having an inlet port and an outlet port for gases, a liquid reservoir having a float valve for controlling the liquid level therein, a single-use, disposable porous evaporative element and a heating element isolated from said liquid reservoir, said humidification chamber having an internal volume of about 200 cc. and being surrounded by said heating element such that heat is transferred directly from the wall of said chamber to said porous evaporative element, said porous evaporative element being an open-ended cylinder having a vertical wicking rate of about two inches in the first minute and fitting loosely within said humidification chamber when dry and swelling into intimate contact with the side wall thereof when wet, one end of said evaporative element extending into said liquid reservoir to wick said liquid into the entire body of said evaporative element, said heating element being electronically controlled to provide respiratory gases to the patient at 100 percent relative humidity at a temperature of about 25°

to 40°

C. within two minutes of start-up, at a continuous flow rate of from about 1 to about 60 liters per minute and a peak inspiratory flow rate of about 10 to about 100 liters per minute, the pressure drop in said humidifier being about 0.1 cm. of water at a continuous flow rate of 30 liters per minute, with flow path of gases into and through said chamber being from said inlet port, along the interior surface of said porous evaporative element and thence through said outlet port, said humidifier being readily disassembled into its component parts for sterilization.

2. An evaporative humidifier according to claim 1 wherein said porous evaporative element comprises cellulosic material bonded together with a water insoluble adhesive.

3. An evaporative humidifier according to claim 2 wherein said porous evaporative element is a laminate of a highly liquid-absorbent cellulosic nonwoven paper and a dimensionally stable, absorbent high wet-strength paper.

4. An evaporative humidifier according to claim 3 wherein said porous evaporative element is flattened for shipping and storage, said evaporative element being restored to its original cylindrical shape by pressing along the creases and inserting same into the humidification chamber.

5. An evaporative humidifier according to claim 1 including electronic control means for interrupting the power supply to said humidifier when the temperature of the heating element or the gases at the patient exceeds a predetermined temperature level.