U.S. patent application number 10/045415 was filed with the patent office on 2003-04-24 for gas/liquid separator including a liquid trap filter.
Invention is credited to Larsen, Michael T., Soroka, Leonid B..
Application Number | 20030075049 10/045415 |
Document ID | / |
Family ID | 21937747 |
Filed Date | 2003-04-24 |
United States Patent
Application |
20030075049 |
Kind Code |
A1 |
Larsen, Michael T. ; et
al. |
April 24, 2003 |
Gas/liquid separator including a liquid trap filter
Abstract
A liquid separator for a respiratory gas sample analyzer
includes a closed container having a liquid trap filter chamber
integral with the container. The liquid trap filter chamber
includes an inlet compartment and an outlet compartment. The inlet
compartment is interposed between a sample inlet port and a sample
outlet port and includes a gas permeable, liquid impermeable filter
element for separating liquid from a gas sample, the liquid
separated from the gas sample passing to a collection chamber. The
outlet compartment includes a further gas permeable, liquid
impermeable trap filter element which is interposed between the
collection chamber and a low pressure port, for preventing the flow
of liquid through the output compartment to the low pressure
port.
Inventors: |
Larsen, Michael T.;
(Brookfield, WI) ; Soroka, Leonid B.; (Whitefish
Bay, WI) |
Correspondence
Address: |
REINHART BOERNER VAN DEUREN S.C.
ATTN: LINDA GABRIEL, DOCKET COORDINATOR
1000 NORTH WATER STREET
SUITE 2100
MILWAUKEE
WI
53202
US
|
Family ID: |
21937747 |
Appl. No.: |
10/045415 |
Filed: |
October 19, 2001 |
Current U.S.
Class: |
96/4 ;
96/413 |
Current CPC
Class: |
B01D 46/543 20130101;
B01D 2265/028 20130101; B01D 46/0031 20130101; B01D 2271/02
20130101 |
Class at
Publication: |
96/4 ;
96/413 |
International
Class: |
B01D 053/22 |
Claims
What is claimed is:
1. A liquid separator for a gas analyzer, said liquid separator
comprising: a closed container including a sample inlet port, a
sample outlet port, and a low pressure port; said container
defining a liquid collection chamber; a liquid trap filter chamber
integral with said container, said liquid trap filter chamber
including an inlet compartment interposed between said sample inlet
port and said sample outlet port for receiving a gas sample
introduced into said sample inlet port, said inlet compartment
having an upper outlet communicated with said sample outlet port
and a lower outlet communicated with said liquid collection
chamber; and a liquid trap filter element contained in said inlet
compartment interposed between said sample inlet port and said
sample outlet port for separating liquid from the gas sample,
liquid separated from the gas sample passing through said lower
outlet to said collection chamber.
2. The liquid separator according to claim 1, wherein said inlet
compartment includes a barrier interposed between said filter
element and said sample outlet port, said barrier defining said
upper outlet.
3. The liquid separator according to claim 2, wherein said liquid
trap filter chamber includes a cover which encloses said filter
element within said inlet compartment.
4. The liquid separator according to claim 3, wherein said cover
includes at least one concave filter engaging surface engaging said
filter element to trap said filter element between said cover and
said barrier.
5. The liquid separator according to claim 1, wherein said filter
element comprises a membrane bearing a polytetrafluoroethylene
laminate.
6. The liquid separator according to claim 1, wherein said liquid
trap filter chamber includes an outlet compartment interposed
between said collection chamber and said low pressure port, said
outlet compartment having an inlet communicated with said
collection chamber and an outlet communicated with said low
pressure port, and a second liquid trap filter element contained in
said outlet compartment interposed between said inlet and said
outlet of said outlet compartment.
7. The liquid separator according to claim 6, wherein said outlet
compartment includes a barrier interposed between said second
filter element and said low pressure port, said barrier defining
said outlet port of said outlet compartment.
8. The liquid separator according to claim 6, wherein said second
filter element comprises a membrane bearing a
polytetrafluoroethylene laminate.
9. The liquid separator according to claim 1, and including a
self-sealing filter in at least one of said sample outlet port and
said low pressure port.
10. A liquid separator for a gas analyzer, said liquid separator
comprising: a sample inlet port; a sample outlet port; an inlet
compartment having an inlet in fluid communication with said sample
inlet port for receiving a gas sample introduced into said sample
inlet port, said inlet compartment having an upper outlet
communicated with said sample outlet port; a liquid collection
chamber in fluid communication with said inlet compartment for
receiving liquid from said inlet compartment; a low pressure port;
an outlet compartment interposed between said collection chamber
and said low pressure port, said outlet compartment having an inlet
communicated with said collection chamber and an outlet
communicated with said low pressure port; and a gas permeable,
liquid impermeable filter element contained in one of said inlet
compartment and said outlet compartment, interposed between said
inlet and outlet of said one compartment for substantially
preventing flow of liquid while allowing the flow of gas from said
inlet to said outlet of said one compartment.
11. The liquid separator according to claim 10, wherein said filter
element is contained in said inlet compartment interposed between
said sample inlet port and said upper outlet for separating liquid
from the gas sample.
12. The liquid separator according to claim 10, wherein said filter
element is contained in said outlet compartment interposed between
said inlet of said outlet compartment and said outlet of said
outlet compartment for substantially preventing the passage of
liquid through said outlet compartment to said low pressure
port.
13. The liquid separator according to claim 10, wherein at least
said one compartment includes a cover separating said inlet and
outlet compartments.
14. A liquid separator according to claim 10, wherein said filter
element comprises a membrane bearing a polytetrafluoroethylene
laminate.
15. The liquid separator according to claim 10, including a
self-sealing filter in at least one of said sample outlet port and
said low pressure port.
16. A liquid separator for a gas analyzer, said liquid separator
comprising: a sample inlet port; a sample outlet port; an inlet
compartment having an upper outlet communicated with said sample
outlet and a lower outlet communicated with said collection
chamber; a gas permeable, liquid impermeable filter element
contained in said inlet compartment interposed between said sample
inlet port and said upper outlet for separating liquid from the gas
sample; said inlet compartment including a barrier interposed
between said filter element and said sample outlet port, said
barrier defining said upper outlet; and a liquid collection chamber
for receiving liquid passed through said lower outlet of said inlet
compartment.
17. The liquid separator according to claim 16, including an outlet
compartment interposed between said collection chamber and said low
pressure outlet, said outlet compartment having an inlet
communicated with said collection chamber and an outlet
communicated with said low pressure port, and a second gas
permeable, liquid impermeable filter element contained in said
outlet trap filter compartment interposed between said inlet and
said outlet of said outlet trap filter compartment.
18. The liquid separator according to claim 17, wherein said
first-mentioned and said second filter elements each comprises a
membrane bearing a polytetrafluoroethylene laminate.
19. A liquid separator for a gas analyzer, said liquid separator
comprising: a sample inlet port; a sample outlet port; a liquid
collection chamber; a separation compartment for separating liquid
from the gas sample, said separation compartment having an upper
outlet communicated with said sample outlet port and a lower outlet
communicated with a collection chamber; a low pressure port; and an
outlet compartment interposed between said collection chamber and
said low pressure port, said outlet compartment having an inlet
communicated with said collection chamber and an outlet
communicated with said low pressure port, and a gas permeable,
liquid impermeable filter element contained in said outlet
compartment interposed between said inlet and said outlet of said
outlet compartment.
20. A liquid separator for a gas analyzer, said liquid separator
comprising: a sample inlet port; a sample outlet port; an inlet
compartment for receiving a gas sample introduced into said sample
inlet port, said inlet compartment having an upper outlet
communicated with said sample outlet port and a lower outlet
communicated with said collection chamber; a first gas permeable,
liquid impermeable filter element contained in said inlet
compartment interposed between said sample inlet port and said
upper outlet for separating liquid from the gas sample; a liquid
collection chamber receiving liquid passed through said lower
outlet of said inlet trap filter compartment; a low pressure port;
an outlet compartment interposed between said collection chamber
and said low pressure port, said outlet compartment having an inlet
communicated with said collection chamber and an outlet
communicated with said low pressure port; and a second gas
permeable, liquid impermeable filter element contained in said
outlet compartment interposed between said inlet and said outlet of
said outlet compartment.
Description
BACKGROUND OF THE INVENTION
[0001] This invention relates to gas/liquid separators for use with
respiratory gas analyzers, and more particularly, to gas/liquid
separator including a liquid trap filter for removing liquid from a
respiratory gas sample.
[0002] Respiratory gas analyzers monitor exhaled air from a
patient. It has long been recognized that means must be provided
for removing excess moisture from the exhaled air prior to
analysis. One technique for removing excess moisture from
respiratory gas samples utilizes the effects of surface tension and
capillary action to separate water from gas samples. Known
gas/liquid separators, or water traps, employing this technique
include a separation chamber which has a geometrical configuration
designed to draw water away from a gas sample outlet and direct the
water to a collection chamber. Examples of such prior art water
traps are disclosed in U.S. Pat. Nos. 4,579,568 and 4,713,095 to
Ricciardelli. However, these prior art water traps can become
filled, and the sample inlet line that conducts exhaled air to the
water trap can become blocked with condensed moisture.
[0003] Another water trap, disclosed in U.S. Pat. No. 4,924,860,
employs a separation chamber having a geometrical configuration
similar to the one disclosed in U.S. Pat. No. 4,713,095. This water
trap additionally includes self-sealing filters which positively
seal the exit ports of the water trap in the event the water trap
becomes over filled and can no longer perform its water trap
function. In one embodiment, one self-sealing filter is disposed in
a sample outlet conduit and a further self-seating filter is
disposed in a vacuum conduit. The self-sealing filters comprise a
porous matrix including means for rendering the porous matrix
substantially non-porous when exposed to water, thereby blocking
the exit ports of the water trap.
SUMMARY OF THE INVENTION
[0004] The present invention provides a liquid separator for use
with a gas analyzer for separating liquid from a gas sample to be
analyzed. The liquid separator comprises a container including a
sample inlet port, a sample outlet port and a liquid trap filter
chamber integral with the container. The liquid trap filter chamber
includes an inlet compartment which has an upper outlet
communicated with the sample outlet port and a lower outlet
communicated with a collection chamber. A liquid trap filter
element is contained in the inlet compartment for separating liquid
from the gas sample, liquid separated from the gas sample passing
through the lower outlet of said inlet compartment to the
collection chamber
[0005] In one embodiment, the liquid trap filter chamber includes
an outlet compartment which is interposed between the collection
chamber and a low pressure port, the outlet compartment having an
inlet communicated with the collection chamber and an outlet
communicated with the low pressure port. A second liquid trap
filter element is contained in the outlet compartment interposed
between the inlet and the outlet of the outlet compartment.
[0006] Further in accordance with the invention, there is provided
a liquid separator for a gas analyzer which comprises a separation
compartment for separating liquid from a gas sample. The separation
compartment includes an upper outlet communicated with a sample
outlet port and a lower outlet communicated with a collection
chamber for receiving and storing liquid separated from the gas
sample. The liquid separator further comprises an outlet
compartment which is interposed between the collection chamber and
a low pressure port. The outlet compartment contains a liquid trap
filter element for preventing the flow of liquid through the outlet
compartment from the collection chamber to the low pressure
port.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] The features of the present invention which are believed to
be novel are set forth with particularity in the appended claims.
The invention, together with the further objects and advantages
thereof, may best be understood by reference to the following
description taken in conjunction with the accompanying drawings,
wherein like reference numerals identify like elements, and
wherein:
[0008] FIG. 1 is a perspective view of a gas/liquid separator in
accordance with the invention;
[0009] FIG. 2 is an exploded view of the gas/liquid separator of
FIG. 1;
[0010] FIG. 3 is a vertical section view of the gas/liquid
separator taken along the line 3-3 of FIG. 1;
[0011] FIG. 4 is a vertical section view of the gas/liquid
separator taken along the line 4-4 of FIG. 1;
[0012] FIG. 5 is a perspective view of a base of the gas/liquid
separator of FIG. 1;
[0013] FIG. 6 is a bottom plan view of the base of FIG. 5;
[0014] FIG. 7 is a vertical section view of the base of FIG. 5;
[0015] FIG. 8 is a perspective view of a top of the gas/liquid
separator of FIG. 1;
[0016] FIG. 9 is a front elevation view of the top of FIG. 8;
[0017] FIG. 10 is a vertical section view of the top of FIG. 8;
[0018] FIG. 11 is a bottom plan view of the top of FIG. 8;
[0019] FIG. 12 is a front perspective view of a cover of the
gas/liquid separator of FIG. 1;
[0020] FIG. 13 is a back perspective view of the cover of FIG.
12;
[0021] FIG. 14 is a plan view of the back of the cover of FIG.
12;
[0022] FIG. 15 is a section view of the cover of FIG. 12;
[0023] FIG. 16 is a perspective view of a mounting clip for use
with the gas/liquid separator of FIG. 1; and
[0024] FIG. 17 is a front elevation view of the mounting clip of
FIG. 16.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0025] Referring to the drawings, FIGS. 1 and 2 illustrate a
gas/liquid separator 10 in accordance with one embodiment of the
invention. The gas/liquid separator 10, hereinafter liquid
separator, includes a closed container 12, a gas/liquid sample
inlet port 14, a liquid trap filter chamber 16, a sample outlet
port 18, a trap reservoir or liquid collection chamber 20 and a low
pressure port 22.
[0026] A gas permeable, liquid impermeable trap filter element 24
is contained in an inlet trap filter compartment 26 of the liquid
trap filter chamber 16, interposed between the inlet port 14 and
the sample outlet port 18 for separating liquid from the
respiratory sample. A further gas permeable, liquid impermeable
trap filter element 28 is contained in an outlet compartment 30 of
the liquid trap filter chamber 16, interposed between the
collection chamber 20 and the low pressure port 22. The liquid
separator 10 can include a self-sealing, hydrophilic filter 34 in
the sample outlet port 18 and a further self-sealing, hydrophilic
filter 36 in the low pressure port 22.
[0027] Briefly, with reference to FIGS. 1, 2 and 3, a sample
respiratory gas of exhaled air is introduced into the liquid
separator through the sample inlet port 14. The liquid trap filter
element 24 in inlet trap filter compartment 26 separates liquid
from the sample respiratory gas. Liquid from the respiratory sample
exits the liquid trap filter compartment 16 and flows into the
liquid collection chamber 20, while the gas sample leaves the inlet
trap filter compartment 26 via the sample outlet port 18. In one
embodiment, the low pressure port 22 can be connected to a vacuum
pump to produce a low pressure within the collection chamber 20 by
withdrawing air from the collection chamber through the outlet trap
filter compartment 30.
[0028] The liquid separator 10 provided by the present invention,
employs a gas permeable, liquid impermeable trap filter element 24
for separating liquid in contrast to a separation chamber, the
operation of which is dependent upon the geometrical configuration
of the separation chamber, as is the case for the water traps
disclosed in the patents referenced above. Moreover, the gas
permeable, liquid impermeable trap filter element 28, which is
interposed between the collection chamber 20 and the low pressure
port 22 as shown in FIG. 4, for example, is used to substantially
prevent liquid from the collection chamber 20 from being drawn
through the outlet trap filter compartment 30 and into the low
pressure port 22.
[0029] Considering the liquid separator 10 in more detail, with
reference also to FIGS. 5-7, the container 12 includes a base 40, a
top 42 and a cover 44. In one embodiment, the base 40, top 42 and
cover 44 are molded of a rigid transparent plastic, such as
plexiglass.
[0030] The base 40, which defines the collection chamber 20, is a
cup-like member which is closed at its lower end by a base member
46 and which has an open upper end defined by an upwardly
projecting side wall 48. The side wall 48 includes a forward
portion 50, a rearward portion 52 and an upper peripheral edge 54.
The outer surface of the base member 46 includes a raised portion
56, which extends forwardly from near rearward portion 52, and a
pair of recesses 58, located near forward portion 50, for a purpose
to be shown.
[0031] The top 42 is mounted on the upper peripheral edge 54 of the
base 40, as shown in FIG. 1, closing the upper end of the base 40
to form the closed container 12 including the collection chamber
20.
[0032] Referring to FIGS. 1, 2, 8, 9 and 11, the top 42 includes a
base 60, a filter housing 62 and a pair of upwardly extending
bosses 64 and 66. The filter housing is located near the forward
portion 61 of the top 42 and defines the liquid trap filter chamber
16. The bosses 64 and 66 are located near the rearward portion 63
of the top 42 and define the sample outlet port 18 and the low
pressure port 22, respectively.
[0033] The inlet trap filter compartment 26 of the liquid trap
filter chamber 16 has a lower outlet 68 in fluid communication with
the collection chamber 20. The lower outlet 68 is located forwardly
of a back wall or barrier 76 of the inlet trap filter compartment
26. Similarly, the outlet trap filter compartment 30 of the liquid
trap filter chamber 16 has a lower inlet 70 in fluid communication
with the collection chamber 20. The lower inlet 70 is located
forwardly of a back wall or barrier 86 of the outlet trap filter
compartment 30.
[0034] The inlet trap filter compartment 26 has an upper outlet 72
located near the center of the cover 42. In one embodiment, the
axis of the upper outlet 72 can be offset with respect to the axis
of the inlet trap filter compartment 26 to bring the upper outlet
72 in line with the sample outlet port 18 while maximizing the
active surface area of the trap filter element 24. The inlet trap
filter compartment 26 further includes a support web 74 formed on
the back wall 76 thereof. The support web 74 supports the trap
filter element 24 within the inlet trap filter compartment 26 to
prevent excessive stress on the trap filter element 24. The support
web spaces the trap filter element 24 forwardly of the back wall
providing an active area through which gas can flow. The support
web 74 also prevents the trap filter element 24 from being drawn
against the back wall 76 by vacuum. The back wall 76 defines the
upper outlet 72 of the inlet trap filter compartment 26.
[0035] Similarly, the outlet trap filter compartment 30 has an
upper outlet 82 (FIG. 9) located near the center of the cover 42.
In one embodiment, the axis of the upper outlet 82 is offset with
respect to the axis of the outlet trap filter compartment 30 to
bring the upper outlet 82 in line with the low pressure port 22
while maximizing the active surface area of the trap filter element
28. The outlet trap filter compartment 30 includes a support web
84, similar in structure and function to support web 74, on the
back wall 86. The support web 84 supports the trap filter element
28 within the outlet trap filter compartment 30, preventing excess
stress on the trap filter element 28 and spaces the trap filter
element 28 forwardly of the back wall 86, providing an active area
through which gas can flow. The support web 84 also prevents the
trap filter element 28 from being drawn against the back wall 86 by
vacuum. The back wall 86 defines the upper outlet 82 for the outlet
trap filter compartment 30. The surface of the top 42 surrounding
the inlet and outlet trap filter compartments 26 and 30 can be
stepped as indicated by reference numbers 90 and 91, respectively.
The top 42 has a stepped inner edge 92 which extends around the
periphery of the trap filter compartments 26 and 30.
[0036] In one embodiment, the gas permeable, liquid impermeable
trap filter elements 24 and 28 can be a membrane filter element
such as GORE-TEX expanded polytetrafluoroethylene (PTFE) laminate
having a one micron pore size on spunbonded polyester, with the
PTFE laminate surfaces 94 and 96 of trap filter elements 24 and 28,
respectively, facing forwardly. In one embodiment, the trap filter
elements 24 and 28 can be permanently bonded to the back walls 76
and 86. The cover 44 is mounted on the top 42, overlying the open
side of the trap filter chamber 16, closing the trap filter chamber
and can aid in holding the trap filter elements 24 and 28 in place
in the inlet and outlet trap filter compartments. The cover 44 also
separates the inlet trap filter compartment 26 from the outlet trap
filter compartment 30.
[0037] The top 42 includes an interior conduit 78, shown in FIGS. 3
and 10, for example, which communicates the upper outlet 72 of the
inlet trap filter compartment 26 with the sample outlet port 18. A
further interior conduit 88 communicates the upper outlet 82 of the
outlet trap filter compartment 30 with the low pressure port 22 as
shown in FIG. 4, for example. The upper outlet 82 is communicated
with the collection chamber 20 only through the trap filter element
28 and the lower inlet 70. There is no direct connection between
the sample outlet port 18 and the collection chamber 20. Also, the
sample inlet 14 is communicated with the sample outlet port 18 only
through the trap filter element 24. The top includes a baffle 87
which extends from the bottom of the cover 42, beneath the liquid
trap filter chamber 16. The baffle 87 extends from near the forward
portion 61 and to the rearward portion 63 of the top 42 and is
located between the reservoir inlet or lower outlet port 68 (FIG.
8) of the inlet trap filter compartment and the lower inlet port 70
outlet trap filter compartment, providing a barrier therebetween.
The baffle 87 blocks the growth of any bubbles emanating from the
trap reservoir inlet 68 before the bubbles can reach the trap
reservoir outlet 70. The baffle 87 slows down the bubbles so that
the bubbles burst prior to reaching the trap reservoir outlet
70.
[0038] In one embodiment, the base 40 and the top 42 can be
produced as independent components with the top 42 being
permanently secured to the base 40 such that the container 12 is an
integral, one-piece member. By way of example, the top 42 can be
secured to the base 40 by ultrasonic welding techniques, or by any
other bonding techniques, such as by the use of epoxy type cement
or solvent type cement. Whatever the technique used, the junction
between the base 40 and the top 42 should be leak proof and secure
in the presence of water and 100% humidity.
[0039] Referring to FIGS. 12-14, the cover 44 includes a flat, oval
base with a hollow cylindrical boss 102 projecting outwardly
therefrom on one side 104 near one end 106 thereof, defining the
inlet port 14. The boss 102 defines a female luer connection as
indicated generally at 108. Referring also to FIG. 15, the boss 102
includes a through bore 110. The cover 44 includes annular steps
112 and 113 which mate with corresponding surfaces of the top 42 to
provide sealing between the cover and the top for the trap filter
inlet and the trap filter outlet compartments.
[0040] The cover 44 has two raised annular portions 114 and 116 on
its opposite side 118. The annular portions 114 and 116 have
concave, filter engaging surfaces 120 and 122 surrounded by an
annular peripheral rims 121 and 123, respectively. One of the
annular filter engaging portions 114 has a notch 124 in rim 121
near its lower end, which is located adjacent to and in fluid
communication with a notch in the cover 42 that defines the lower
outlet 68 of the inlet trap filter compartment 26, outwardly of the
trap filter element 24. Liquid trapped at the forward side of the
filter element can pass through the notch 124 to the lower outlet
or trap reservoir outlet 68. Similarly, annular portion 116 has a
notch 126 in rim 123 near its lower end which is located adjacent
to and in fluid communication with a notch in the cover 42 that
defines the lower inlet or trap reservoir outlet 70 of the outlet
trap filter compartment 30. In one embodiment, the cover 44 can be
secured to the top 42 by ultrasonic welding techniques, or by any
other bonding techniques, such as by the use of epoxy type cement
or solvent type cement. Whatever the technique used, the junction
between the cover 44 and the top 42 should be leak proof and secure
in the presence of water and 100% humidity.
[0041] Referring to FIG. 16, there is shown a mounting clip 130
which can be used to facilitate attachment of the liquid separator
to a gas analyzer (not shown) with which it is used. The mounting
clip 130 includes a base portion 132 with a pair of flexible arms
133, 134 with hooked ends. The arms 133 and 134 are sized to engage
the raised portion on the outer surface of the base member. The
mounting clip 130 includes projections or posts 136 which are
received in the recesses 58 (FIG. 6) in the outer surface of the
base member 46. The mounting clip 130 can be made of a plastic
material such as cycoloy, for example.
[0042] Referring to FIGS. 1, 6 and 16, the mounting clip 130 can be
pressed onto the bottom of the base 40, with the posts 136 located
in the recesses 58 and the arms 133 and 134 fitting around and
resiliently engaging the raised bottom portion 56 of the base
member 46. In another embodiment, one or both of the back outer
corners 152 and 154 of the base 40 (FIGS. 3 and 6) can include a
serrated surface and/or can project outwardly beyond the plane of
the adjacent pair of sides 156, 158 and 158, 160, to provide a
interference fit between the liquid separator and the manifold of a
gas analyzer with which the liquid separator is used. In this
embodiment, the retaining clip does not have to be used.
[0043] Referring to FIGS. 1-4, the self-sealing, hydrophilic line
filters 34 and 36 can be similar to those disclosed in U.S. Pat.
No. 4,924,860, which is incorporated herein by reference for its
teaching as to self-sealing filters. Filter plugs 140 and 142 can
be pressed into the top of the bosses 64 and 66 and be glued or
otherwise secured to the bosses to maintain the line filters 34 and
36 in place. The filter plugs 140 and 142 can be made of a plastic
material such as plexiglass, for example.
[0044] As more fully described in U.S. Pat. No. 4,924,860
referenced above, the self-sealing filters 34 and 36 preferably
comprise a cellulose extract disposed in the plastic material to
seal the pores when it comes into contact with a liquid, such as
water. The self-sealing filters 34 and 36 are normally "open". The
filters 34 and 36 ensure that no fluid contamination is able to
reach the gas monitoring system with which the gas/liquid separator
10 is used. For example, in the event the collection chamber 20
becomes filled with collected water and water rises to a level
sufficient to allow the water to come into contact with the
self-sealing filters 34 and 36, the filters 34 and 36 immediately
become non-porous, thereby sealing the respective conduits as to
both liquid flow and gas flow therethrough. As is described in
detail in U.S. Pat. No. 4,924,860, the filters 34 and 36 operate as
a water sensor which signals undesired water presence to a suitable
control system for appropriate action. In this way, liquid,
including water and mucous secretions, are reliably prevented from
entering the gas analyzer. This is an important advantage, because
considerable time and expense can be required to clean a gas
analyzer once contaminated by liquid.
[0045] Referring to FIGS. 1, 3, and 4, the operation of the liquid
separator 10 is apparent from the foregoing detailed description,
and accordingly, the following is a brief description of the
operation. A vacuum is applied to the low pressure port 22, drawing
air out of the collection chamber 20 through the outlet trap filter
compartment 30. The low pressure port 22 is normally in fluid
communication with the outlet side of the outlet trap filter
compartment 30 through conduit 88 and the upper outlet 82. The
inlet side of the outlet trap filter compartment 30, in turn, is
communicated with the collection chamber 20 through lower inlet 70.
However the trap filter element 28 in the outlet trap filter
compartment 30 substantially blocks the passage of liquid from the
collection chamber 20 to the low pressure port 22.
[0046] A sample respiratory gas of exhaled air is introduced into
the gas/liquid sample inlet port 14 and passed into the inlet trap
filter compartment. The trap filter element 24 in inlet trap filter
compartment 26 separates liquid from the sample respiratory gas.
Liquid from the sample falls by gravity to the bottom of the inlet
trap filter compartment 26 and flows through the lower outlet 68
into the liquid collection chamber 20. The gas sample, passed
through the filter element 24, passes through the upper outlet 72
and conduit 78 to the sample outlet port 18 from which the gas
sample can be applied to a gas analyzer (not shown).
[0047] The container 12 is transparent to allow a care giver to
know when the collection chamber 20 is close to being filled so
that the liquid separator 10 can be changed. In the event the
liquid separator 10 becomes over filled and can no longer perform
its function, the self-sealing filter 34 and 36, disposed in the
sample outlet port 18 and low pressure outlet 22 become
substantially non-porous, thereby blocking the exit ports of the
liquid separator 10.
[0048] The liquid separator 10 can be used in a conventional gas
analyzer in which the physical sealing effect provided by the
self-sealing filters 34 and 36 protects the gas analyzer from
liquid contamination. However, the liquid separator 10 is
preferably used in a gas analyzer, such as that disclosed in U.S.
Pat. No. 4,924,860, referenced above, which monitors pressures in a
conduit coupled to the low pressure port and a conduit coupled to
the sample outlet port to detect sealing by the self-sealing
filter.
[0049] While preferred embodiments have been illustrated and
described, it should be understood that changes and modifications
can be made thereto without departing from the invention in its
broadest aspects. Various features of the invention are defined in
the following claims.
* * * * *