Systems and methods for humidity control

Patent metadata

Field	Value
Publication number	US-2016184547-A1
Application number	US-201414587898-A
Country	US
Kind code	A1
Filing date	Dec 31, 2014
Priority date	Dec 31, 2014
Publication date	Jun 30, 2016
Grant date	—

Abstract

Systems, methods, and devices for humidifying a breathing gas using a vapor transfer unit are presented. The method includes providing a first vapor transfer unit having a gas passage and a liquid passage, delivering a liquid to the liquid passage, delivering a gas to the gas passage, humidifying the gas by delivering vapor from the liquid in the liquid passage to the gas in the gas passage, exiting the humidified gas outside the vapor transfer unit at first relative humidity and at a high gas flow rate, and reducing the gas flow rate through the first vapor transfer unit to less than a low gas flow rate, while preventing the relative humidity from exceeding the first relative humidity by more than an acceptable margin.

First claim

1 . A vapor transfer unit for humidifying breathing gas, the vapor transfer unit comprising:
a housing having a gas inlet and a gas outlet; a plurality of tubes disposed within the housing and each defining a passage for a flow of gas from an upstream end of the passage to a downstream end of the passage; a valve positionable between a first position and a second position; wherein the valve obstructs the flow of gas through a first subset of the plurality of tubes when in the first position; and wherein the valve obstructs the flow of gas through a second subset of the plurality of tubes, different from the first set, when in the second position.

2 . The vapor transfer unit of claim 1 , wherein the plurality of tubes comprises a first group and a second group, wherein tubes of the first group are porous and tubes of the second group are non-porous.

3 . The vapor transfer unit of claim 1 or 2 , wherein the first position corresponds to a first ratio of unobstructed porous tubes to unobstructed non-porous tubes, and wherein the second position corresponds to a second ratio of unobstructed porous tubes to unobstructed non-porous tubes.

4 . The vapor transfer unit of claim 3 , wherein the first ratio is greater than the second ratio.

5 . The vapor transfer unit of claim 4 , wherein the first ratio is greater than about 50 and the second ratio is less than about 25.

6 . The vapor transfer unit of claim 1 , wherein a first number of tubes included in the first subset is greater than a second number of tubes included in the second subset.

7 . The vapor transfer unit of claim 1 , wherein the valve is positionable to a plurality of intermediate positions, wherein the plurality of intermediate positions is between the first and second positions.

8 . The vapor transfer unit of claim 1 , wherein the gas inlet is positioned to direct gas to the upstream end of each of the passages of the tubes.

9 . The vapor transfer unit of claim 1 , wherein the gas outlet is positioned to direct gas from the downstream end of each of the passages of the tubes.

10 . The vapor transfer unit of claim 1 , wherein the housing further comprises:
a liquid inlet positioned to direct liquid toward outer surfaces of the tubes; and a liquid outlet positioned to direct liquid from the housing.

11 . The vapor transfer unit of claim 1 , wherein the plurality of tubes comprises a first group and a second group, wherein tubes of the first and second groups are porous.

12 . The vapor transfer unit of claim 1 , wherein the second group of tubes is configured to prevent liquid from contacting outer surfaces of tubes of the second group.

13 . A method for humidifying a breathing gas using a vapor transfer unit, the method comprising:
delivering breathing gas to a plurality of tubes disposed within a housing; directing liquid toward outer surfaces of the plurality of tubes; obstructing gas flow through a subset of the plurality of tubes; and adjusting a humidity level of gas output from the vapor transfer unit by adjusting the subset of obstructed tubes.

14 . The method of claim 13 , wherein a first group of the tubes are porous and a second group of the tubes are non-porous.

15 . The method of claim 14 , wherein the plurality of tubes comprises a number of unobstructed porous tubes and a number of unobstructed non-porous tubes; and wherein adjusting the subset of obstructed tubes comprises changing a ratio of the number of unobstructed porous tubes to the number of unobstructed non-porous tubes from a first ratio to a second ratio.

16 . The method of claim 15 , wherein the first ratio is greater than 50 and the second ratio is less than 25.

17 . The method of claim 13 , wherein adjusting the subset of obstructed tubes comprises changing a total number of obstructed tubes.

18 . The method of claim 13 , wherein the gas is delivered at a flow rate of greater than 8 liters per minute.

19 . The method of claim 13 , wherein liquid is directed to outer surfaces of a first group of the plurality of tubes and is not directed to outer surfaces of a second group of the plurality of tubes.

20 . A system for humidifying breathing gas, the system comprising:
a housing having a liquid inlet, a liquid outlet, a gas inlet, and a gas outlet; a vapor transfer compartment disposed within the housing and having:
a first gas passage coupling the gas inlet to the gas outlet;
a liquid passage coupling the liquid inlet to the liquid outlet; and
a porous membrane separating the first gas passage and the liquid passage; and
a bypass gas passage disposed within the housing and coupling the gas inlet to the gas outlet, the bypass gas passage comprising a constriction and being configured to receive a fraction of the gas received by the gas inlet; wherein the constriction is sized so that the fraction of gas received by the bypass passage decreases as a rate of gas flow into the gas inlet increases.

21 . The system of claim 20 , wherein a cross-sectional area of the constriction is fixed.

22 . The system of claim 21 , wherein the porous membrane comprises a plurality of hollow fiber membranes.

23 . The system of claim 22 , wherein the first gas passage is defined by internal walls of the plurality of hollow fiber membranes.

24 . The system of claim 23 , wherein the liquid inlet is formed in the housing and is positioned to direct liquid toward outer surfaces of the hollow fiber membranes and the liquid outlet is positioned to direct liquid from the housing.

25 . A method for humidifying a breathing gas using a vapor transfer unit, the method comprising:
delivering gas to a vapor transfer unit having a vapor transfer device and a bypass gas passage, wherein the gas is delivered at a gas flow rate; passing a fraction of the gas through the bypass gas passage; and automatically altering the fraction of the gas passed through the bypass gas passage inversely with a change in the gas flow rate.

26 . The method of claim 25 , further comprising maintaining fixed internal dimensions of the vapor transfer unit.

27 . The method of claim 26 , wherein passing the fraction of the gas through the bypass gas passage comprises passing gas through a constriction, wherein the constriction is sized so that the fraction of gas received by the bypass gas passage decreases as the gas flow rate increases.

28 . The method of claim 27 , further comprising delivering liquid to the vapor transfer device.

29 . The method of claim 28 , wherein the vapor transfer device includes a first gas passage and a liquid passage, and wherein the gas is delivered to the first gas passage and the liquid is delivered to the liquid passage.

30 . The method of claim 29 , wherein the vapor transfer device comprises a plurality of hollow fiber membranes.

31 . The method of claim 30 wherein delivering the liquid comprises directing liquid toward outer surfaces of the plurality of hollow fiber membranes.

32 . The method of claim 25 , wherein the gas is delivered at a flow rate of greater than or equal to about 8 liters per minute.

33 . The method of claim 25 , wherein the gas is delivered at a flow rate of greater than or equal to about 30 liters per minute.

34 . The method of clai

Assignees

• Vapotherm Inc

Inventors

• Leonard Scott A
• Kate Meghan H

Classifications

• A61M16/0003

  Accessories therefor, e.g. sensors, vibrators, negative pressure · CPC title

• A61M16/0875

  Connecting tubes · CPC title

• A61M16/16 Primary

  Devices to humidify the respiration air {(A61M16/1045 takes precedence)} · CPC title

• A61M2205/3327

  Measuring · CPC title

• A61M16/20

  Valves specially adapted to medical respiratory devices · CPC title