Moisture Removal and Condensation and Humidity Management Apparatus for a Breathing Circuit

Abstract

A moisture removal and condensation and humidity management apparatus for a breathing circuit comprises a breathing circuit tubing defining a breathing gas conduit. The breathing gas has a first humidity level and a level of moisture therein. A dry gas conduit is adjacent at least a portion of the breathing gas conduit. The dry gas flow is configured to have a second humidity level lower than the first humidity level. A moisture transmission pathway is provided between the breathing gas conduit and the dry gas conduit, such that humidity in the flow of breathing gas is lowered and moisture is transferred to the dry gas flow. The moisture transmission pathway may be provided by a permeable portion which is permeable to water vapor but impermeable to liquid water, or by one or more perforations which permit drainage of liquid water from the breathing gas conduit to the dry gas conduit.

1 . A moisture removal apparatus comprising:
 a first tube;   a second tube, the first tube and the second tube defining:
 a breathing gas conduit that directs a flow of breathing gas in a direction from an upstream end of the apparatus to a downstream end of the apparatus; and 
 a dry gas conduit that directs a dry gas flow in the direction from the upstream end of the apparatus to the downstream end of the apparatus; and 
   a moisture transmission pathway between the breathing gas conduit and the dry gas conduit that lowers the humidity of the breathing gas by transferring the humidity to the dry gas flow.   
     
     
         2 . The moisture removal apparatus of  claim 1 , wherein the moisture transmission pathway is permeable to water vapor but impermeable to liquid water. 
     
     
         3 . The moisture removal apparatus of  claim 1 , wherein the first tube is an inner tube and the second tube is an outer tube that is concentric with the inner tube. 
     
     
         4 . The moisture removal apparatus of  claim 3 , wherein the inner tube defines the breathing gas conduit, and further comprising an annular space between the inner tube and the outer tube, the annular space defining the dry gas conduit. 
     
     
         5 . The moisture removal apparatus of  claim 1 , wherein at least one of the first tube or the second tube is a corrugated tube. 
     
     
         6 . The moisture removal apparatus of  claim 3 , wherein the inner tube includes a permeable portion that defines the moisture transmission pathway that is permeable to water vapor but impermeable to liquid water. 
     
     
         7 . The moisture removal apparatus of  claim 6 , wherein the permeable portion spans the entire wall of the inner tube. 
     
     
         8 . The moisture removal apparatus of  claim 6 , wherein the permeable portion includes a hydrophilic polyester ester membrane. 
     
     
         9 . The moisture removal apparatus of  claim 1 , further comprising:
 an exit port fluidly coupled to the dry gas conduit; and   a filter fluidly coupled to the exit port.   
     
     
         10 . The moisture removal apparatus of  claim 1 , wherein the apparatus is configured to be an expiratory limb of a ventilator circuit. 
     
     
         11 . The moisture removal apparatus of  claim 1 , wherein the dry gas conduit is a first dry gas conduit, the dry gas flow is a first dry gas flow, the direction is a first direction, and further comprising:
 a return conduit that directs a second dry gas flow in a second direction from the downstream end to the upstream end of the apparatus.   
     
     
         12 . A moisture removal apparatus comprising:
 an inner tube defining a breathing gas conduit that directs a flow of breathing gas, the inner tube including a permeable portion that defines a moisture transmission pathway that is permeable to water vapor;   an outer tube concentric with the inner tube;   an annular space between the inner tube and the outer tube, the annular space defining a first dry gas conduit that directs a first dry gas flow in a first direction from a first end of the apparatus to a second end of the apparatus; and   a return conduit that directs a second dry gas flow in a second direction from the second end of the apparatus to the first end of the apparatus.   
     
     
         13 . The moisture removal apparatus of  claim 12 , wherein the return conduit is positioned within the annular space. 
     
     
         14 . The moisture removal apparatus of  claim 13 , further comprising a dividing wall between the inner tube and the outer tube that divides the annular space into the first dry gas conduit and the return conduit. 
     
     
         15 . The moisture removal apparatus of  claim 12 , wherein the outer tube is a corrugated tube; and
 wherein the moisture transmission pathway is impermeable to liquid water.   
     
     
         16 . The moisture removal apparatus of  claim 12 , wherein the apparatus is configured to be an expiratory limb of a ventilator circuit. 
     
     
         17 . A moisture removal apparatus comprising:
 a breathing circuit tube including:
 a breathing gas conduit that directs a flow of breathing gas in a first direction from a first end of the apparatus to a second end of the apparatus; and 
 a dry gas conduit that directs a first dry gas flow in the first direction; and 
   a moisture transmission pathway between the breathing gas conduit and the dry gas conduit that lowers the humidity of the breathing gas by transferring the humidity to the first dry gas flow; and   wherein the moisture removal apparatus includes at least one of:
 a return conduit that directs a second dry gas flow in a second direction from the second end of the apparatus to the first end of the apparatus; or 
 a dividing wall that divides the breathing circuit tube into the breathing gas conduit and the dry gas conduit, the dividing wall including a permeable portion that defines the moisture transmission pathway, the moisture transmission pathway being permeable to water vapor. 
   
     
     
         18 . The moisture removal apparatus of  claim 17 , wherein the breathing circuit tube is a corrugated tube. 
     
     
         19 . The moisture removal apparatus of  claim 17 , wherein the moisture transmission pathway is impermeable to liquid water. 
     
     
         20 . The moisture removal apparatus of  claim 17 , wherein the moisture removal apparatus includes the return conduit that directs the second dry gas flow in the second direction from the second end of the apparatus to the first end of the apparatus; and
 further comprising:   an inner tube that defines the breathing gas conduit; and   an outer tube concentric with the inner tube, the inner tube and outer tube defining an annular space between the inner tube and the outer tube, the annular space defining the breathing gas conduit; and   wherein the return conduit is positioned within the annular space.