U.S. patent application number 10/715164 was filed with the patent office on 2004-08-26 for personally portable vacuum desiccator.
Invention is credited to Watson, Richard.
Application Number | 20040167482 10/715164 |
Document ID | / |
Family ID | 25543492 |
Filed Date | 2004-08-26 |
United States Patent
Application |
20040167482 |
Kind Code |
A1 |
Watson, Richard |
August 26, 2004 |
Personally portable vacuum desiccator
Abstract
The vacuum desiccator low pressure vacuum pump and trap and is
transportable upon a user's person. The device is especially useful
to remove excess fluids from wounds and incisions as they heal. The
device includes a desiccator cartridge containing a fluid trapping
agent. The desiccator cartridge is connected to a vacuum pump
member providing a low vacuum pressure to the interior chamber of
the desiccator cartridge. A small battery powered, electric motor
drives the pump member. An electrical control circuit, including
the battery power source, controls the operation of the electric
motor. A single passage, one-way, gas/liquid flow pathway connects
the inlet port of the desiccator cartridge to an occlusive dressing
covering the wound to be drained. The control circuit includes one
or more ancillary circuits for controlling operation of the device,
such as: a power circuit, a moisture sensor, a timer circuit, a
vacuum pressure sensor, and a pressure differential sensor.
Inventors: |
Watson, Richard; (McPherson,
KS) |
Correspondence
Address: |
LOEFFLER JONAS & TUGGEY, LLP
755 EAST MULBERRY STREET
SUITE 200
SAN ANTONIO
TX
78212
US
|
Family ID: |
25543492 |
Appl. No.: |
10/715164 |
Filed: |
November 17, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10715164 |
Nov 17, 2003 |
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09996970 |
Nov 20, 2001 |
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6648862 |
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Current U.S.
Class: |
604/317 |
Current CPC
Class: |
A61M 1/784 20210501;
A61M 1/0001 20130101; A61M 2205/8206 20130101 |
Class at
Publication: |
604/317 |
International
Class: |
A61M 001/00 |
Claims
What is claimed is:
1. A personally portable vacuum desiccator comprising: moisture
trap, the trap further comprising a desiccator cartridge having an
interior chamber containing a trapping agent, and an inlet port and
an outlet port in gas/liquid communication with the interior
chamber; a vacuum pump member having a low pressure port and an
exhaust port, the low pressure port in gas/liquid flow
communication with the outlet port of the desiccator cartridge and
with the exhaust port vented to atmosphere, and the vacuum pump
member being operable to provide a low vacuum pressure to the
interior chamber; an electric motive means in communication with
the vacuum pump member and operative to drive the vacuum pump
member; and an electrical control circuit, including an electrical
power source, the control circuit in electrical communication with
and operative to control operation of the electric motive
means.
2. The personally portable vacuum desiccator of claim 1, further
comprising a single passage gas/liquid flow path delivery tube,
having an input end and an output end, the output end being
connected to the inlet port of the desiccator cartridge.
3. The personally portable vacuum desiccator of claim 1, further
comprising a housing containing the electric motive means and the
electrical control circuit.
4. The personally portable vacuum desiccator of claim 1, further
comprising a housing containing the electric motive means and the
electrical control circuit and at least one additional element
selected from the group consisting of the desiccator cartridge and
the vacuum pump member.
5. The personally portable vacuum desiccator of claim 1, wherein
the vacuum pump member is integral with the desiccator
cartridge.
6. The personally portable vacuum desiccator of claim 1, wherein
the electric motive means includes an electric motor mechanically
coupled to the vacuum pump member.
7. The personally portable vacuum desiccator of claim 1, wherein
the electric motive means includes an electric motor magnetically
coupled to the vacuum pump member.
8. The personally portable vacuum desiccator of claim 1, wherein
the electrical control circuit includes an electrical power source
comprising a battery.
9. The personally portable vacuum desiccator of claim 1, wherein
the electrical control circuit includes an electrical power source
comprising a battery, and the battery is removable from the
electrical control circuit and replaceable.
10. The personally portable vacuum desiccator of claim 1, further
comprising a one-way valve disposed proximate the inlet port of the
desiccator cartridge, the one-way valve preventing gas/liquid and
particulate flow out of the inlet port.
11. The personally portable vacuum desiccator of claim 1, wherein
the electrical control circuit includes a moisture sensor for
detecting the presence of moisture proximate the low pressure port
of the vacuum pump member.
12. The personally portable vacuum desiccator of claim 1, wherein
the electrical control circuit includes a timer circuit for
intermittently operating the electric motive means.
13. The personally portable vacuum desiccator of claim 1, wherein
the electrical control circuit includes a vacuum pressure sensor
for detecting a vacuum pressure in the interior chamber of the
desiccator cartridge.
14. The personally portable vacuum desiccator of claim 1, wherein
the electrical control circuit includes a pressure differential
sensor for sensing a difference in pressure between the inlet and
outlet ports of the desiccator cartridge.
15. The personally portable vacuum desiccator of claim 1, wherein
the desiccator cartridge is removable from the vacuum desiccator
and replaceable.
16. The personally portable vacuum desiccator of claim 1, wherein
components in gas/liquid flow communication are replaceable.
17. The personally portable vacuum desiccator of claim 1, wherein
the desiccator cartridge contains a trapping agent selected from
the group consisting of: a desiccant, an adsorbent and an
absorbent.
18. The personally portable vacuum desiccator of claim 1, further
comprising a micro-filter positioned after the outlet port of the
desiccator cartridge and before the exhaust port of the vacuum pump
member, the micro-filter blocking the passage of bacteria.
19. The personally portable vacuum desiccator of claim 1, where in
the power source is integrally combined with the desiccator
cartridge, and the combined desiccator-power source being
installable in and removable from the vacuum desiccator as a single
unit.
20. A personally portable vacuum desiccator comprising: a
desiccator cartridge, the cartridge being removable from the vacuum
desiccator and replaceable, and having an interior chamber
containing a trapping agent, the trapping agent being a moisture
trapping pillow, and an inlet port and an outlet port in gas/liquid
communication with the interior chamber, and a one-way valve
disposed proximate the inlet port for preventing gas/liquid and
particulate flow out of the input port; a single passage gas/liquid
flow pathway having an input end and an output end, the output end
being connected to the inlet port of the desiccator cartridge; a
vacuum pump member having a low pressure port and an exhaust port,
the low pressure port in gas/liquid flow communication with the
outlet port of the desiccator cartridge and with the exhaust port
vented to atmosphere, and the vacuum pump member being operable to
provide a low vacuum pressure to the interior chamber; an electric
motive means in communication with the vacuum pump member and
operative to drive the vacuum pump member, the electric motive
means including an electric motor coupled to the vacuum pump
member; and an electrical control circuit, including an electrical
power source, the control circuit in electrical communication with
and operative to control operation of the electric motive means,
the electrical power source comprising a battery, with the battery
being removable from the electrical control circuit and
replaceable, and wherein the electrical control circuit includes
one or more ancillary circuits selected from the group consisting
of a power circuit for turning the electrical control circuit on
and off, a moisture sensor for detecting the presence of moisture
proximate the low pressure port of the vacuum pump member, a timer
circuit for intermittently operating the electric motive means, a
vacuum pressure sensor for detecting a vacuum pressure in the
interior chamber of the desiccator cartridge, a pressure
differential sensor for sensing a difference in pressure between
the inlet and outlet ports of the desiccator cartridge.
Description
BACKGROUND OF THE INVENTION
[0001] A number of portable, low pressure vacuum apparatuses
capable of producing vacuum pressures down to about 500 mm HG
currently exist. Medicine, particularly the wound healing arts, is
a field where such devices have a specific utility. In the wound
healing arts, it has been recognized that the removal of excess
fluid from a wound site can improve the healing of the wound. This
recognition has motivated the field to develop wound treatment
regimens that include the use of vacuum devices for removing excess
exudate from a wound site. For example, in full thickness dermal
wounds devices to assist in the removal of excess fluid from these
wounds have been developed and used. Further, because of the
recognized benefits of encouraging patients to be active and mobile
if possible, these devices need to be portable, and preferably,
personally portable.
[0002] One strategy for providing a personally portable, low
pressure vacuum source for drainage of wound site involves the use
of a passive vacuum reservoir. Examples of this types of device
includes those disclosed by Fell, U.S. Pat. No. 5,073,172; Seddon
et al., U.S. Pat. No. 6,024,731; and Dixon et al., U.S. Pat. No.
5,944,703. Typically, these devices comprise an evacuated cannister
attached to a drainage tube. Because the vacuum pressure in the
reservoir of these devices continuously decreases as the wound is
drained (and the reservoir filled), they often include a means for
regulating the pressure delivered to the wound site at some level
below the maximum pressure of the vacuum reservoir. Additionally,
these devices require a reservoir of a relatively larger volume
than that of the volume of fluid they are capable of removing from
a wound site.
[0003] Recognizing these limitations, the field has been further
motivated to develop means for providing a portable, low pressure
vacuum source for drainage of a user's wound site which provides a
relatively constant vacuum pressure. A strategy for accomplishing
this objective includes having the device comprise a vacuum pump to
provide a constant low pressure vacuum source, or to replenish a
separate vacuum reservoir. An example of this type of device
includes that disclosed by McNeil et al., U.S. Pat. No. 4,710,165.
Also see U.S. Pat. No. 5,134,994 to Say. Although portable, these
devices are bulky and obvious to an observer of the user, and may
subject the user to embarrassment or personal questions. It would
be beneficial to have a portable vacuum device that was personally
portable by the user without being obvious to an observer.
[0004] An apparatus which addresses this latter benefit is
disclosed in U.S. Pat. No. 6,142,892 to Hunt et al. The Hunt
apparatus is supported on a belt or harness worn by the user, and
is small enough to be unobtrusive when worn under a jacket or the
like. However, the Hunt apparatus utilizes a liquid reservoir
containing the fluids drained from a wound site. Fluids contained
in the liquid reservoir of Hunt are subject to slouching, which may
adversely affect the function of the Hunt apparatus if the fluid
prematurely enters an inappropriate pathway (the outlet end of the
cannister). Also, the Hunt device requires multiple tubes or a
multi-lumen tube running from the device to the wound site to
accomplish its full utility. Additionally, the Hunt apparatus is
intended to be worn by a patient at waist level or higher. This
means that wound sites below and distal to the user's waist can be
subjected to a higher vacuum pressure than with a device that may
be located more proximal the wound site than the Hunt
apparatus.
[0005] Although the above apparatuses may be useful in the field
for accomplishing their intended purposes, it would be beneficial
to have an alternative personally portable vacuum device that can
be worn unobtrusively by the user, and which is not subject to
slouching of the fluid it retains, and further which does not
require special tubing to connect it to a wound site.
SUMMARY OF THE INVENTION
[0006] The present desiccator is a personally portable vacuum pump
and moisture trapping device. The invention is useful where a user
desires to carry a device for collecting and trapping small volumes
of liquids. As a specific example, the present invention is
therapeutically useful to provide a personally portable low
negative pressure source and trap for aspirating and collecting
fluid exudate from a wound or incision. A further benefit of the
present invention for such applications involving biological waste
is that the trap and all other components of the desiccator device
that contact the aspirated biological materials are removable from
the device and are replaceable. The desiccator device includes a
trap, a vacuum pump head member, an electric motive mechanism and
an electric control and power circuit.
[0007] The trap comprises a desiccator cartridge enclosing an
interior space or chamber. An inlet port and an outlet port provide
gas/liquid flow communication with the interior chamber of the
desiccator cartridge. The desiccator cartridge is of a design and
construction to withstand the application of an appropriate vacuum
without substantial collapse of the interior chamber. Some
distortion of the cartridge while under vacuum is desirable in some
applications, e.g., where buffering of the vacuum pressure of the
system is beneficial. A trapping agent is contained within the
interior chamber for retaining the fluid that enter the chamber.
The composition of the trapping agent is selectable by one of
ordinary skill in the art in view of the teaching herein and in
consideration of the characteristics of the fluid to be
trapped.
[0008] A vacuum pump member or pump head is connected in gas flow
communication with the interior chamber of the trap by having the
low pressure port of the vacuum pump member being connected to the
outlet port of the trap. The exhaust port of the vacuum pump member
is vented to atmosphere. Operation of the vacuum pump member
develops a low vacuum pressure which is communicated to the
interior chamber of the desiccator cartridge and then to the inlet
port of the trap. The vacuum pressure at the inlet port of the trap
is selectable by the ordinary skilled artisan depending on the
intended use of the present device. Typically, the selected vacuum
pressures range less than about 250 mm Hg, and in part depends on
the vacuum pressure to be delivered to the wound site and the any
loss of vacuum pressure across the delivery tube connecting the
inlet port to the wound site. An electric motive means (an electric
motor) is coupled to the vacuum pump member and drives the pump
head. An electrical control circuit, including an electrical power
source, is in electrical communication with the electric motive
means. The control circuit is operable to control the operation of
the electric motive means.
[0009] The desiccator cartridge of the trap has only a single,
ingress gas/liquid flow pathway, which is the inlet port.
Additionally, the flow path at the inlet port is unidirectional, in
that gas/liquid flow can enter the trap via the inlet port, but not
exit or back flow out of the trap via the inlet port. Optionally,
the personally portable vacuum desiccator includes a single passage
gas/liquid flow path delivery tube for connecting the trap to a
source of gas or liquids to be delivered into the trap. The
delivery tube has an input end for communicating with the
gas/liquid source and an output end connectable to the inlet port
of the desiccator cartridge. A one-way valve is located proximate
the inlet port of the desiccator cartridge. The one-way valve
prevents the contents of the desiccator cartridge from back-flowing
out of the inlet port. The one way valve may be separate from or
incorporated into the inlet port. The desiccator cartridge is
removable from the vacuum desiccator and separately disposable. A
fresh desiccator cartridge is installed in the desiccator to
replace the removed cartridge.
[0010] The desiccator cartridge contains a trapping agent for
containing the liquids or moisture delivered to the trap under the
force of the vacuum. The trapping agent combines with the liquid or
moisture to alter its physical features, i.e., from a liquid or
vapor to a mixed phase or solid state. Compositions suitable for
use as trapping agents in the present invention are selectable by
one of ordinary skill in the art in view of the present disclosure
and teachings herein. The trapping agent should adsorb, absorb or
in some way combine with the liquid or moisture to immobilize and
keep it from sloshing in the desiccator cartridge as it is
accumulated in the interior chamber. Examples of potentially
suitable trapping agents include: a desiccant, an adsorbent and an
absorbent. Specific examples include silica gel, sodium
polyacrylate, potassium polyacrylamide and related compounds. Such
moisture trapping materials are often found in disposable baby
diapers and in feminine napkins. The level of moisture in the
desiccant chamber is monitored by the moisture sensor circuit. When
the amount of moisture trapped in desiccant material approaches
saturation, the chamber may either be removed and disposed of or
recharged with fresh desiccant material and repositioned in the
device (depending on the design of the desiccator cartridge).
[0011] The present vacuum desiccator can further comprise a filter
for blocking bacteria and/or untrapped moisture from passing into
the vacuum pump member or from being vented to atmosphere. The
filter may be located proximate the outlet port to protect the pump
member and/or proximate the exhaust port to prevent venting
bacteria or moisture to atmosphere.
[0012] The electric motive means of the vacuum desiccator includes
an electric motor. The motor is coupled to the vacuum pump member
to drive the pump. The motor may be coupled to the pump head by any
of a number of means known to and practicable by the ordinary
skilled artisan. For example, the motor shaft may be integrated
with the vacuum pump head, it may be mechanically coupled to the
vacuum pump so as to be readily separable from the pump head, or it
may be magnetically coupled to the pump head so as to, again, be
readily separable from the vacuum pump member. A readily separable
motive means is particularly useful where the vacuum pump member
and the desiccator cartridge are integrated together as a unit.
[0013] A purpose of the electrical control circuit is to monitor
the condition of the device and to control operation of the motive
means. The electrical control circuit includes the electrical power
source for the device. The power source comprises an electrical
power storage means, such as a battery. A feature of the power
source is that the electrical storage means is removable from the
electrical control circuit and is replaceable. Additionally, the
electric control circuit optionally includes other ancillary
circuits for the operation and control of the device. These
circuits include: a moisture sensor circuit for detecting the
presence of moisture proximate the low pressure port of the vacuum
pump member; a timer circuit for intermittently operating the
electric motive means; a vacuum pressure sensor circuit for
detecting a vacuum pressure in the interior chamber or elsewhere in
the device; and a pressure differential sensor circuit for sensing
a difference in pressure between the inlet and outlet ports of the
desiccator cartridge.
[0014] The component parts of the vacuum desiccator device which
are in gas/liquid flow communication are replaceable. This allows
the components of the device which are exposed to contact with the
wound fluids to be separable from the other components of the
device to facilitate cleaning or disposal of contaminated
components.
[0015] The present personally portable vacuum desiccator can
further comprise a housing for containing some or all of the
component parts of the device. For example, the housing may contain
the electric motive means and the electrical control circuit, while
the other components are simply attached to the housing, e.g., an
integrated pump head/trap combination assembly. Other
configurations obviously are possible, such as a housing containing
the electric motive means and the electrical control circuit and
additionally either or both of the trap (desiccator cartridge) and
the vacuum pump member.
[0016] Additionally, the present vacuum desiccator device may
comprise the battery being housed in a battery compartment attached
or integral to the desiccator cartridge of the moisture trap. In
this configuration, the battery and the desiccator cartridge are
replaceable in the device as a single unit.
[0017] It is a feature of the present invention that the personally
portable vacuum desiccator can be used as part of a treatment
regimen to promote wound healing by drawing excess wound exudate
away from the wound site. As an example of using the desiccator for
this purpose, an open, full thickness dermal wound is covered with
an air tight dressing, such as are commercially available. The
input end of the gas/liquid flow delivery tube is positioned under
the dressing in flow communication with the wound site. The vacuum
desiccator is activated, a low negative pressure is produced at the
wound site via the delivery tube and excess fluids excreted by the
wound are removed under the force of the low negative pressure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIG. 1 is a schematic diagram of the major components of the
present vacuum desiccator showing the electric control circuit
contained in a housing with the motor coupled to the trap and
vacuum pump member.
[0019] FIG. 2A is a side elevation and partial cross-sectional view
of the desiccator cartridge of the present device, showing the
interior chamber containing a trapping agent.
[0020] FIG. 2B is a top plan and partial cross-section view of the
desiccator cartridge showing the interior chamber containing
alternative trapping agents and showing alternative moisture/fluid
sensors for detecting fluid in flow path proximate the outlet port
of the cartridge. Also shown is a separately mountable outlet
micro-filter.
[0021] FIG. 3 is a partial top plan view of the outlet port portion
of the desiccator cartridge showing in phantom a micro-filter
integral to the desiccator cartridge flow path, and also a vacuum
pressure sensor mountable to the outlet port of the cartridge.
[0022] FIG. 4 is a cross-sectional view through a side elevation of
a combination of a desiccator cartridge and vacuum pump head as an
integral unit.
[0023] FIG. 5A is a partial top plan view of the inlet portion of
the desiccator cartridge showing the inlet port with a one-way
gas/fluid flow valve installed.
[0024] FIGS. 5B and 5C are partial cross-sectional views of two
types of one-way gas/liquid flow valves.
[0025] FIG. 6 is a block diagram of the electric control circuit of
the desiccator device indicating its sub-circuits and the
interconnect relationship with certain ancillary components.
[0026] FIGS. 7A and 7B show alternative strain-gauge means for
monitoring vacuum pressure in the interior chamber of the
desiccator cartridge.
[0027] FIG. 8 is a partial cross-section of a side elevation of a
desiccator cartridge showing the interior components and their
layout.
[0028] FIG. 9A is an exploded view of a side elevation of a
desiccator cartridge showing a cover member incorporating an
integral gas flow channel.
[0029] FIG. 9B is a bottom plan view of the cover member of FIG. 9A
illustrating an example of an integral gas flow channel layout (in
phantom) and the perforations by which the integral channel is in
gas flow communication with the interior chamber of the desiccator
cartridge.
DETAILED DESCRIPTION OF THE INVENTION
[0030] The personally portable vacuum desiccator is a device useful
as a source for providing a low vacuum pressure for removing excess
wound exudate from dressed dermal wounds. This application of
present personally portable vacuum desiccator is useful for
promoting wound healing by draining such excess wound exudate from
the wound site.
[0031] Referring now to the drawings, the details of preferred
embodiments of the present invention are graphically and
schematically illustrated. Like elements in the drawings are
represented by like numbers, and any similar elements are
represented by like numbers with a different lower case letter
suffix.
[0032] As shown in FIG. 1, the present invention is a personally
portable vacuum desiccator 10 comprises a trap 12, a vacuum pump
member operable to provide a source of low vacuum pressure, an
electric motive or drive means 36 for operating the vacuum pump
member, and an electrical control circuit, including an electrical
power source. The control circuit is electrically connected to the
electric motive means to control its operation, i.e., to turn it on
and off. The trap 12 includes a desiccator cartridge 14 The
desiccator cartridge 14 has an interior chamber 16 containing a
trapping agent 54 (see FIG. 2). Additionally, the desiccator
cartridge 14 has an inlet port 18 and an outlet port 20 in
gas/liquid communication with the interior chamber 16 of the
cartridge 14. A vacuum pump head or member 22 serves as a source
for a low pressure vacuum of about 250 mm Hg or less. The vacuum
pump member 22 is placed after desiccant chamber 14 in the
gas/liquid flow pathway to facilitate preventing fluid from
entering the vacuum pump member. The vacuum pump head 22 has a low
pressure port 24 and an exhaust port 26. The low pressure port 22
is in gas/liquid flow communication with the outlet port 20 of the
desiccator cartridge 14. The exhaust port 26 of the vacuum pump
head 22 is vented to atmosphere. When operated, the vacuum pump
member 22 provides a low vacuum pressure to the interior chamber 16
of the desiccator cartridge. As further shown in FIG. 1., an
electric motive means 36 is in communication with the vacuum pump
member 22 via a coupling 38. The electric motive means 36 is a low
voltage electric motor, which is operable to drive the vacuum pump
member 22, thus providing a low vacuum pressure at the pump
member's low pressure port 24. The electrical control circuit 40,
including an electrical power source 46, is in electrical
communication with the electric motive means 36 via an electric
motor lead 42. The control circuit 40 controls the operation of the
electric motive means.
[0033] Optionally, a delivery tube 32 is included with the
desiccator device 10 to put the trap 14 in gas/liquid flow
communication with a location to which a low negative vacuum
pressure is to be applied, such as a wound site covered by an
occlusive dressing (not shown). The delivery tube 32 consists of a
single passage gas/liquid flow path, having an input end 33 and an
output end 24, the output end 34 being connected to the inlet port
18 of the desiccator cartridge 14.
[0034] The components of the personally portable vacuum desiccator
10 can further comprise a housing 50 for containing or mounting the
component parts of the vacuum desiccator 10. As exemplified in FIG.
1, the housing 50 contains the electric motive means 26 and the
electrical control circuit 40. Alternatively, the housing 50 can
contain the electric motive means 36, the electrical control
circuit 40 and additionally, the desiccator cartridge 14 and/or the
vacuum pump member 22.
[0035] The trap 12 comprises a desiccator cartridge 14. As shown in
FIGS. 2A and 2B, the desiccator cartridge 14 encloses an interior
space or chamber 16. The desiccator cartridge 14 is of a design and
material construction to withstand the application of an
appropriate vacuum without substantial collapse of the interior
chamber 16. Some distortion of the cartridge while under vacuum is
desirable in some applications, e.g., where buffering of the vacuum
pressure of the system is beneficial or distortion of the chamber
16 is used as an index of the vacuum pressure within the interior
chamber 16.
[0036] A trapping agent 54 is contained within the interior chamber
16 to retain (trap) fluids and moisture that enter the chamber 16.
There are a variety of compositions available in the art that are
appropriate trapping agents for practice in the present invention.
A specific composition or combination of compositions useful as the
trapping agent 54 is readily selectable by one of ordinary skill in
the art in view of the teaching herein and in consideration of the
characteristics of the fluid to be trapped. Examples of classes of
such compositions suitable as trapping agents 54 include
desiccants, adsorbents, absorbents and the combination of any of
these. Specific examples include silica gel, sodium polyacrylate,
potassium polyacrylamide and related compounds. Such moisture
trapping materials are often found in disposable baby diapers and
in femnine napkins. These compositions may be particulate trapping
agents 54a or fibrous trapping agents 54b. In a preferred
embodiment, the trapping agent 54 was a pillow-like structure (see
FIG. 8), which included a fiber matrix material which served to
contain and somewhat immobilize the other loose components of the
trapping agent, and to act as a wick to distribute the fluid as it
entered the interior chamber. The level of moisture in the interior
chamber 16 proximate the outlet port 20 is monitored by a moisture
sensor 84 (see FIG. 1). When the amount of moisture retained by the
trapping agent 54 approaches saturation (as detected by the
moisture sensor 84 or indicated by other means), the desiccator
cartridge 14 may either be removed and disposed of or recharged
with fresh desiccant material and repositioned in the device
(depending on the design of the desiccator cartridge). Other means
for detecting the degree of saturation of the trapping agent 54 are
available. For example, the desiccant cartridge 14 may be
constructed in part from a transparent material, allowing the
trapping agent 54 to be directly observed. The degree of saturation
of the trapping agent 54 maybe indicated by a color change in a
component of the trapping agent 54 in response, for example, to a
pH change or degree of hydration.
[0037] In a preferred embodiment of the vacuum desiccator 10, all
of the components in gas/liquid flow communication are replaceable.
This allows the components of the device that are exposed to
contact with the wound fluids to be separable from the other
components of the device to facilitate cleaning or disposal of
contaminated components. In particular, the desiccator cartridge 14
is removable from the device 10 and separately disposable. A fresh
desiccator cartridge 14 is installed in the desiccator 10 to
replace the removed cartridge. Alternatively, the cartridge 14 can
be constructed to make its interior chamber 16 accessible, e.g.,
through a lid or by disassembly, whereby the used trapping agent 54
can be replaced with fresh. The refreshed desiccator cartridge may
then be reattached to vacuum desiccator 10. This feature may be
useful where the desiccator cartridge and vacuum pump head are
combined as a single integrated unit (see FIG. 4).
[0038] The desiccator cartridge 14 has a single, gas/liquid flow
pathway, which is the inlet port 18, as the only inlet path into
the trap 12. The flow path at the inlet port 18 is unidirectional,
in that gas/liquid flow can enter the trap via the inlet port 18,
but not exit or back flow out of the trap 14 via the inlet port 18.
Unidirectional flow at the inlet port is accomplished by a one-way
valve 30 located proximate the inlet port 18 of the desiccator
cartridge 14 (see FIG. 5A). The one-way valve 30 prevents the
contents of the desiccator cartridge 14 from back-flowing out of
the inletport 18. The one-way valve 30 maybe separable from the
desiccator cartridge 14, as shown in FIG. 5A, or it may be
incorporated into the cartridge 14 proximate the inlet port 18 (not
shown). One-way gas/liquid flow valves practicable in the present
invention are known in the art and selectable by the ordinary
skilled artisan for use in the present invention. Examples of such
one-way valves include biased and/or unbiased piston-type 30a and
ball-stop 30b valves as exemplified in FIGS. 5B and 5C.
[0039] A micro-filter 28 useful for blocking bacteria and/or
untrapped moisture from passing into the vacuum pump member or from
being vented to atmosphere is located in the gas/liquid flow path
of the device 10 after the interior chamber 16 of the desiccator
cartridge. The micro-filter 28 may be located proximate the outlet
port 20 to protect the pump member 22 and/or proximate the exhaust
port 26 to prevent venting bacteria (or moisture) to atmosphere.
The micro-filter may be an in-line micro-filter 28a separate from
the desiccator cartridge as shown in FIG. 2B, or an integral
micro-filter 28b incorporated into the cartridge 14 proximate the
outlet port 20 as shown in FIG. 3.
[0040] As shown in FIG. 1, an electric motive means 36 is coupled
to the vacuum pump member 22 of the vacuum desiccator 10. In the
preferred embodiment, the motive means 36 is an electric motor.
Electric motors practicable in the present invention are known to
and selectable by one of ordinary skill in the art in view of the
teachings and figures contained herein. For example, a miniature,
oil-less diaphragm pump is commercially available from the Gast
Manufacturing, Inc. (Michigan): series 3D1060, model 101-1028. The
electric motor 36 communicates with the vacuum pump member 22 via a
drive coupling 38 to drive the pump. The drive coupling 38 for
connecting the motor 36 to the pump head 22 may be accomplished by
any of a number of means known to and practicable by the ordinary
skilled artisan. For example, a motor shaft coupling 38 may be
integrated with the vacuum pump head, i.e., the motor 36 and pump
member 22 are substantially a single unit. Alternatively, a motor
shaft coupling 38 may be mechanically coupled to the vacuum pump
head 22 so as to be readily separable from the pump head 22. For
instance, as exemplified in FIG. 4, the hub 100 of a rotary-vane
pump head 22a has a motor shaft receiver 102 for accepting the end
or spindle of a shaft coupling 38 of a motor 36. The shaft receiver
102 has a threaded, keyed or similar interfacing configuration (not
shown) complementary to the spindle or end of the shaft coupling 38
of the motor 36. As a further alternative, the motor 36 may be
magnetically coupled (not shown) to the pump head 22 so as to again
be readily separable from the vacuum pump member 22. A readily
separable motive means 36 is particularly useful where the vacuum
pump member 22 and the desiccator cartridge 14 are integrated
together as a unit, as shown in FIG. 4.
[0041] As shown in FIG. 6, the present vacuum desiccator device 10
includes an electrical control circuit 40 that comprises logic and
switching circuits and a number of ancillary circuits and
functions, external sensors, electrical connections and a power
source. In the preferred embodiment, the purpose of the electrical
control circuit 40 is to monitor the condition of the device 10 and
to control operation of the motive means 36. The ancillary circuits
can be chosen for inclusion in an embodiment of the device 10 to
affect one or more of the following functions: device data
Input/Output, electrical power, sensor signal processing and motor
control (power to the motor). An I/O unit 70 for accomplishing
device data input and out put can include data input means such as
a power and data entry switches (e.g., a key pad and/or on-off
switch), and a readout display and alarms. Such I/O units 70 are
well known in the art, and are readily practicable in the present
invention by the ordinary skilled artisan. Other ancillary circuits
and other sensors 88 may be provided at the user's option, and are
similarly accomplishable by the ordinary skilled artisan.
[0042] In the preferred embodiment exemplified in FIG. 1, the power
source 46 for storing and providing electrical energy for the
device 10 is a battery 60. In the preferred embodiment, the power
source 46 is removable from the electrical control circuit 40 and
is easily replaceable. The POLAROID.RTM. P100 Polapulse.TM. battery
is an example of an appropriate battery 60 useful as a power source
46 in the present vacuum desiccator device 10 in a preferred
embodiment because of its planar configuration and low profile. See
FIGS. 7A and 7B.
[0043] It is intended that the electrical control circuit have
sensory capabilities to detect certain physical conditions of the
device 10, and to utilize the conditions to control operation of
the motor 36, and other appropriate functions of the control
circuit 40. These ancillary sensory circuits include: a moisture
sensor 84 and circuit, for detecting the presence of moisture
proximate the outlet port 20 of the desiccant cartridge 14; at
least one vacuum pressure sensor 76 and circuit, for detecting a
vacuum pressure in the interior chamber or elsewhere in the device;
and a pressure differential sensor circuit, for sensing a
difference in pressure between two sections of the gas/liquid flow
pathway of the device 10, e.g., between the inlet and outlet ports
18 & 20 of the desiccator cartridge 14. The sensors are
interconnected to the control circuit 40 via electrical leads 44.
Sensors appropriate for accomplishing the various sensory functions
of an electrical control circuit are known in the art and are
readily adaptable for practice in the present invention by the
ordinary skilled artisan. For example, a vacuum pressure sensor 76
(MPL model 500, diaphragm-type pressure differential sensor)
suitable for practice in the present device is commercially
available from Micro Pneumatic Logic, Inc. (Florida) from a line of
pressure sensors. Other types of sensors are adaptable for use in
the present invention for detecting or sensing pressure, such as
surface strain gauges mounted on the surface of the desiccator
cartridge 14, and optical displacement gauges mounted to transmit
light through the surfaces of desiccator cartridge 14. For example,
an optical fiber strain gauge 77 is commercially available from
FISO Technologies (Quebec, model FOS "C" or "N") from a line of
optical strain gauges. This sensor can be used to monitor and
indicate the presence of a vacuum in the desiccator cartridge by
displacement (bending) of the cartridge surface under the force of
a vacuum in the interior chamber 16. Optical displacement/strain
gauges 78 are also commercially, including for the detection of
fluid intrusion into a section of tubing. These gauges typically
comprise a combination light source/detector 78a and a mirror 78b.
Distortion of the surface of the desiccator cartridge 14 on which
the mirror 78b is mounted alters the reflection path of the emitted
light as it passes through the cartridge to return to the detector,
which alteration is detectable. Of course, this requires the walls
of the cartridge 14 proximate the optical displacement gauge 78 to
be transparent to the light. The use of more than one pressure
sensor 76 can allow sensing and/or measurement of the pressure
differential between two different points in the gas/liquid flow
pathway, such as between the inlet and outlet ports 18 & 20 of
the desiccator cartridge 14.
[0044] The vacuum pressure sensor 76 is used to monitor the vacuum
pressure in the interior chamber 16 of the desiccator cartridge 14.
When the vacuum pressure detected in the chamber 16 by the pressure
sensor 76 is sufficient, the electric control circuit 40 may switch
off the motor 36, thereby conserving electrical power. When the
vacuum pressure detected in the chamber 16 by the pressure sensor
76 is no longer sufficient, the control circuit 40 may switch on
the motor 36 to reestablish an appropriate vacuum pressure in the
interior chamber 16 of the desiccator cartridge 14. Also, the
electrical control circuit 40 can include a clock/timer circuit for
intermittently operating the electric motive means 36, as another
way of conserving electrical power. The I/O unit 70 can be utilized
to set the time interval for the control circuit's intermittent
operation of the motor 36.
[0045] In an alternative preferred embodiment of the vacuum
desiccator 10, the battery 60 of the power source 46 is integral
with the desiccator cartridge 14a. As exemplified in FIG. 8, the
battery 60 is contained in a battery compartment 110, which is
integral to the structure of the desiccator cartridge 14a. Battery
leads 112 connect the battery 60 to electrical battery contacts 114
on the exterior surface 120 of the desiccator cartridge 14a. In
this embodiment, the desiccator cartridge 14a and battery 60 are
replaceable as a unit.
[0046] FIG. 8 also illustrates another preferred feature of a
desiccator cartridge 14, in which a gas flow channel is disposed
inside the interior chamber 16 of the cartridge 14a. In the
embodiment illustrated, the flow channel 120 is a tube connected to
the outlet port 20 and having a length sufficient to allow it to be
coiled or snaked about the interior chamber 16 (also see FIG. 9B).
The flow channel tube 120 has perforations 122 along its length, or
is otherwise constructed, to allow gas flow from the interior
chamber 16 into the lumen of the flow channel tube 120 under the
force of the vacuum pressure from the pump member 22. Further shown
in FIG. 8, is trapping agent 54c having a pillow-like structure.
The flow channel tube 120 is laid out on one side of the pillow
trapping agent 54c. In the preferred embodiment, the pillow
trapping agent 54c was constructed using 10 grams of sodium
polyacrylate distributed between two layers of an elastic mesh
material (nylon stocking). In addition to elastic mesh material,
other fabrics are suitable for practice with the moisture trapping
pillow 54c, including knitted fabric mesh materials like gauze and
similar fabrics. To maintain even distribution of the sodium
polyacrylate, the two layers of elastic mesh material were sewn
together to form compartments. The volume of the interior chamber
16 of the desiccator cartridge 14 was sufficient to hold the pillow
and about 50 cc of trapped moisture.
[0047] A flow channel may be accomplished by means other than a
tube. For example, a flow channel may be integrated into the
desiccator cartridge 14 and be in gas flow communication with the
interior chamber 16. This embodiment of a desiccator cartridge 14
can be accomplished as shown in FIGS. 9A and 9B, wherein the
cartridge 14b has a cover member 124 and a body member 126 (FIG.
9A). The cartridge cover member 124 has a gas flow channel 120a
integrated into it. The integral flow channel 120a has perforations
122a along its length, or is otherwise constructed, to allow gas
flow from the interior chamber into the lumen of the integral
channel 120a under the force of the vacuum pressure from the pump
member 22.
[0048] While the above description contains many specifics, these
should not be construed as limitations on the scope of the
invention, but rather as exemplifications of one or another
preferred embodiment thereof. Many other variations are possible,
which would be obvious to one skilled in the art. Accordingly, the
scope of the invention should be determined by the scope of the
appended claims and their equivalents, and not just by the
embodiments.
* * * * *