U.S. patent number RE31,315 [Application Number 06/321,192] was granted by the patent office on 1983-07-19 for apparatus for converting a pump to a controller.
This patent grant is currently assigned to Imed Corporation. Invention is credited to Raymond E. Cannon, Jon A. Jenkins.
United States Patent |
RE31,315 |
Jenkins , et al. |
July 19, 1983 |
Apparatus for converting a pump to a controller
Abstract
Apparatus is provided for assuring that fluid is introduced from
a pump to a receiver, such as a patient, at a controlled and safe
pressure. This arrangement includes conduit means, such as inlet
and outlet lines, which extend from the pump to the receiver and
which are included in a disposable unit. The disposable unit
includes detent means cooperative with detent means in the pump to
hold the disposable unit in releasable relationship with the pump.
Resilient means such as diaphragm are disposed in the conduit means
in the disposable unit. The resilient means expand or contract in
accordance with the pressure of the fluid in the outlet line.
Actuatable means such as an actuatable arm is disposed in the
disposable unit and is captured in the conduit means and is
positioned in abutting relationship with the diaphragm for movement
with the diaphragm. When the pressure of the fluid in the output
line reaches a particular value, the actuating arm becomes
displaced through a particular distance to operate sensing means
external to the disposable unit. The operation of the sensing means
causes an output indicator to be energized. The particular pressure
for operating the sensing means is dependent upon the adjustable
positioning of control means, such as a knob, external to the
disposable unit. The manual adjustment of the knob causes a control
member to be adjusted in position. The adjustment in the position
of the control member may produce a corresponding adjustment in the
force required to actuate the arm, thereby producing an adjustment
in the fluid pressure at which the sensing means becomes
operative.
Inventors: |
Jenkins; Jon A. (Rancho Sante
Fe, CA), Cannon; Raymond E. (San Diego, CA) |
Assignee: |
Imed Corporation (San Diego,
CA)
|
Family
ID: |
26732467 |
Appl.
No.: |
06/321,192 |
Filed: |
November 13, 1981 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
Reissue of: |
053981 |
Jul 2, 1979 |
04277227 |
Jul 7, 1981 |
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|
Current U.S.
Class: |
417/63; 200/83S;
200/83Y; 604/31; 604/67 |
Current CPC
Class: |
A61M
5/14224 (20130101); F04B 49/10 (20130101); A61M
5/16854 (20130101) |
Current International
Class: |
A61M
5/168 (20060101); A61M 5/142 (20060101); F04B
49/10 (20060101); B04B 021/00 (); A61M
005/20 () |
Field of
Search: |
;417/63,214,38,45
;128/214E,214F,DIG.12,DIG.13 ;250/551 ;200/83R,83J,83S,83Y |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Jenkins; Robert W.
Attorney, Agent or Firm: Roston; Ellsworth R. Schwartz;
Charles H.
Claims
.[.I.]. .Iadd.We .Iaddend.claim:
1. In combination for use with a pump for introducing fluid to a
receiver and for controlling the pressure of the fluid introduced
by the pump to the receiver, the pump having detent means,
an output line for passing the fluid from the pump to the
receiver,
a resilient diaphragm connected in the output line for constraint
in accordance with the pressure of the fluid in the line,
means movable with the diaphragm for obtaining the production of an
output indication when the pressure of the fluid in the output line
has reached a particular level,
a housing holding the output line, the diaphragm and the movable
means, and
detent means on the housing for co-operating with the detent means
on the pump for releasably holding the housing in a particular
fixed relationship with the pump.
2. The combination set forth in claim 1 wherein
the housing is constructed to capture the movable means to provide
for a disposition of the movable means on the diaphragm and a
movement of the movable means with the diaphragm.
3. The combination set forth in claim 2 wherein
the housing defines an output line at one end of the housing and
defines an input end at the other end of the housing and defines a
chamber between the input and output lines and wherein the
diaphragm is disposed in the chamber.
4. The combination set forth in claim 1 wherein
means are adjustable to control the force required to move the
movable means through each increment of distance in accordance with
variations in fluid pressure and wherein means are included for
providing the output indication when the movable means has moved
through a particular distance.
5. The combination set forth in claim 1 wherein
means are adjustable to control the distance through which the
movable means is moved to obtain an output indication.
6. The combination set forth in claim 1 wherein
the diaphragm is disposed in a particular relationship to the input
and output lines in the housing and is stretched across the housing
between the input and output lines.
7. In combination for use with a pump for introducing fluid at
controlled pressures to a receiver and for providing an output
indication when the pressure of the fluid exceeds a particular
value, the pump having detent means,
conduit means extending from the pump to the receiver to introduce
fluid from the pump to the receiver,
resilient means included in the conduit means for variable
positioning in accordance with variations in the pressure of the
fluid in the conduit means,
actuatable means operatively coupled to the resilient means for
movement with the resilient means to obtain the production of the
output indication when the resilient means has reached a particular
position, and
detent means disposed externally of the conduit means for
co-operating with the detent means on the pump to hold the circuit
means in a particular fixed relationship to the pump.
8. The combination set forth in claim 7 wherein
means are associated with the conduit means for capturing the
actuatable means to retain the actuating means for movement with
the resilient means.
9. The combination set forth in claim 7 wherein
the conduit means define input and output lines and a chamber
between the input and output lines and wherein in the conduit means
support the resilient means in the chamber at a particular position
above the input and output lines.
10. The combination set forth in claim 9 wherein
means are associated with the conduit means for capturing the
actuatable means to retain the actuatable means for movement with
the resilient means and wherein
adjustable means are associated with the actuatable means to
control the variations in fluid pressure required to produce
increments in the movement of the resilient means and the
actuatable means.
11. The combination set forth in claim 9 wherein
means are associated with the conduit means for capturing the
actuatable means to retain the actuating means for movement with
the resilient means and wherein
adjustable means are associated with the actuatable means to
control the variations in the distance of movement of the
actuatable means required to obtain the production of the output
indication.
12. The combination set forth in claim 7 wherein
the resilient means constitutes a diaphragm and the actuatable
means constitutes an arm movable with the diaphragm.
13. The combination set forth in claim 7 wherein
the resilient means constitutes a diaphragm and the actuatable
means constitutes an arm movable with the diaphragm and the
adjustable means constitutes a manually movable knob and the
variably positioned means constitutes a control lever operatively
coupled to the knob for pivotable movement in accordance with the
manual adjustments of the knob.
14. The combination for controlling the flow of fluid to a
receiver,
a pump,
conduit means extending from the pump to the receiver to introduce
fluid from the pump to the receiver,
resilient means included in the conduit means for variable
positioning in accordance with variations in the pressure of the
fluid in the conduit means,
actuatable means included in the conduit means and operatively
coupled to the resilient means for movements with the resilient
means to obtain the production of the output indication when the
resilient means has reached a particular position,
sensing means associated with the actuatable means for sensing when
the actuatable means has moved through a particular distance,
and
detent means disposed in cooperative relationship on the pump and
the conduit means for retaining the conduit means in a particular
fixed, but removable, relationship to the pump.
15. The combination set forth in claim 14 wherein
means are associated with the conduit means for capturing the
actuatable means to retain the actuating means for movement with
the resilient means.
16. The combination set forth in claim 14 wherein
the sensing means are included in the pump and wherein the pump
also includes resilient means associated with the actuatable means
in the conduit means for variable positioning in accordance with
the variable positioning of the actuatable means and further
includes actuatable means operatively coupled to the resilient
means in the pump for movement with such resilient means and
wherein the sensing means are included in the pump and are
associated with the actuatable means in the pump for sensing when
such actuatable means has moved through a particular distance.
17. The combination set forth in claim 14 wherein
adjustable means are included for controlling the fluid pressure at
which the sensing means becomes operative and
means are included in the sensing means for variable positioning in
accordance with the adjustment of the adjustable means to control
the positioning of the actuatable means at which the sensing means
becomes operative.
18. In combination for controlling the flow of fluid to a
receiver,
a disposable unit including inlet and outlet lines and a chamber
between the inlet and outlet lines and a resilient diaphragm
disposed in the chamber between the inlet and outlet lines and
responsive to the pressure of the fluid in the chamber to become
positioned in accordance with such fluid pressure and including
detent means,
a pump including detent means disposed for cooperation with the
detent means on the disposable unit to hold the disposable unit in
removable relationship, the pump being constructed to pump fluid to
the input line, and
means associated with the pump and responsive to the positioning of
the resilient diaphragm for interrupting the operation of the pump
when the resilient diaphragm has reached a particular position.
19. The combination set forth in claim 18 wherein
the means for interrupting the operation of the pump are included
in the pump.
20. The combination set forth in claim 19 wherein
the means for interrupting the operation of the pump include a
resilient diaphragm disposed on the face of the pump and
positionable in accordance with the positioning of the diaphragm in
the disposable unit and wherein means are disposed in the pump and
are responsive to the positioning of the resilient diaphragm in the
pump for interrupting the operation of the pump when the resilient
diaphragm has reached a particular position.
21. The combination set forth in claim 18 wherein
the means for interrupting the operation of the pump are separate
from the pump.
22. In combination for controlling the flow of fluid to a
receiver,
a pump for pumping fluid to the receiver,
conduit means for receiving the fluid from the pump and for
introducing the fluid to the receiver,
first means associated with the conduit means and responsive to
variations in the pressure of the fluid in the conduit means for
variable positioning in accordance with such variations in fluid
pressure, and
second means responsive to variations in the positioning of the
first means for producing a signal for discontinuing the operation
of the pump when the first means has been displaced through a
particular distance,
the conduit means and the first means being disposed in a cassette
and first detent means being provided in the pump and second detent
means being provided in the cassette for cooperation with the
detent means on the pump to provide a releasable coupling between
the cassette and the pump,
the conduit means including a housing and inlet and outlet
lines,
the first means including a chamber between the inlet and outlet
lines, and
means disposed in the chamber and responsive to the pressure of the
fluid in the chamber for variable positioning in accordance with
such variations in fluid pressure,
the second detent means being disposed on the housing and the first
detent means include spring arms on the pump for releasably holding
the second detent means.
23. The combination set forth in claim 22 wherein
the second means are included in the pump.
24. A method of controlling the pressure of a fluid being pumped
from a source to a patient, including the following steps:
providing a pump for pumping the fluid from the source to the
patient and operatively coupling the pump between the source and
the patient,
passing the pumped fluid through a cassette containing a resilient
diaphragm constrainable in accordance with the pressure of the
fluid passing through the cassette,
converting the constraint of the resilient diaphragm to a movement
of an output member,
providing a member adjustable in positioning and cooperative with
the output member to provide an output signal at a position of the
output member dependent upon the adjustment in the positioning of
the adjustable member, and
interrupting the operation of the pump upon the production of the
output signal to maintain within particular limits the pressure
introduced to the patient,
the constrainable diaphragm in the cassette being coupled to a
constrainable diaphragm in the pump to produce a constraint of the
constrainable diaphragm in the pump in accordance with the
constraint of the diaphragm in the cassette and the output member
being disposed in the pump and being movable in accordance with the
constraint of the diaphragm in the pump and the adjustable member
being disposed in the pump.
25. In combination for converting a pump into a controller for
controlling within particular limits the pressure of fluid
introduced from a source to a patient,
a housing having an inlet and an outlet for the flow of fluid and
having a chamber in communication with the inlet and the
outlet,
a resilient diaphragm disposed in the chamber and constrainable in
accordance with the pressure of the fluid in the chamber,
a pivotable member,
a light source,
a photocell,
means for providing for a variation in the amount of the light
passing from the light source to the photocell in accordance with
the variations in the positioning of the resilient member, and
means responsive to a particular change in the passage of the light
from the source to the photocell for indicating that the pressure
of the fluid within the housing has exceeded the particular
limits.
26. The combination set forth in claim 25, including,
detent means on the housing for providing for a removable
attachment of the housing to the pump.
27. In combination for converting a pump into a controller for
controlling within particular limits the pressure of fluid
introduced from a source to a patient,
a housing,
detent means on the housing for releasable attachment to the
pump,
an inlet into the housing for receiving the fluid,
an outlet from the housing for providing for the transfer of the
fluid from the housing,
a chamber within the housing in communication within the inlet and
the outlet,
a diaphragm disposed across the chamber for constraint in
accordance with the pressure of the fluid in the chamber, and
an arm disposed in communication with the diaphragm for
transferring the constraint of the diaphragm as a force into the
pump.
28. The combination set forth in claim 27 wherein
the diaphragm seals the chamber at one end and wherein the arm
extends through the housing for communication with the pump.
29. The combination set forth in claim 27 wherein
the housing is provided with an opening at one end in communication
with the chamber and wherein the diaphragm is disposed across the
opening to seal the chamber from the opening and wherein the
diaphragm is constrainable in a direction to extend into the
opening in accordance with increases in the pressure of the fluid
in the chamber and wherein the arm is extended through the opening
to transfer the constraint of the diaphragm into the pump.
30. The combination set forth in claim 29 wherein
the housing is shaped to facilitate a manual manipulation of the
housing into releasable attachment with the pump and wherein the
detent means is disposed on the housing.
31. In combination in a disposable unit for operating in
conjunction with a pump to control within particular limits the
pressure of fluid introduced from a source to a patient,
a housing,
detent means on the housing,
an inlet for receiving the fluid from the source,
an outlet for passing the fluid to the patient,
a resilient diaphragm disposed across the chamber to close the
chamber and to become constrained in accordance with the pressure
of fluid in the chamber,
a reinforcement on the diaphragm at an intermediate position on the
diaphragm,
an opening disposed in the housing in communication with the
reinforcement at the end of the housing opposite the chamber,
and
force-transmitting means disposed in cooperative relationship with
the reinforcement and extending through the opening to produce a
force in the pump in accordance with the constraint of the
diaphragm.
32. The combination set forth in claim 31 wherein
the force-transmitting means constitutes an arm disposed in
cooperative relationship with the reinforcement and wherein
there is a passage in the housing in communication with the opening
and the passage is provided with dimensions converging toward the
opening and wherein
the arm has a tubular portion extending through the passage and the
opening to transmit the force on the diaphragm.
33. The combination set forth in claim 32 wherein
the reinforcement is hollow and the arm is disposed within the
hollow interior of the reinforcement.
34. In combination for controlling the pressure of fluid passing
from a source to a patient,
a pump for pumping fluid from the source to the patient,
a casing supported by the pump,
there being a socket in the casing,
detent means in the socket,
a disposable unit including a housing dimensioned to fit into the
socket and including detent means disposed on the housing to
cooperate with the detent means in the socket for removably
retaining the disposable unit in the socket,
there being a chamber in the housing,
an inlet disposed in the housing and communicating with the chamber
to provide for the introduction of fluid from the source into the
chamber,
an outlet disposed in the housing and communicating with the
chamber to provide for the passage of fluid from the chamber to the
patient,
a resilient diaphragm disposed in the chamber to close the chamber
and constrainable in accordance with the pressure of the fluid in
the chamber, and
means disposed in the pump and responsive to the constraint of the
diaphragm for providing an output indication when the pressure of
the fluid in the chamber has reached a particular limit.
35. The combination set forth in claim 34, including,
a knob on the face of the pump casing, the knob being adjustable to
different positions representing individual limits for the pressure
of the fluid in the chamber, and
the indicating means including means responsive to the adjustments
in the positioning of the knob for providing the output indication
when the pressure of the fluid in the chamber has reached the
particular limit represented by the adjustments in the positioning
of the knob.
36. In combination for controlling within particular limits the
pressure of fluid introduced from a source to a patient,
a pump for pumping the fluid from the source at a positive
pressure,
a housing having an inlet and an outlet for the flow of fluid and
having a chamber in communication with the inlet and the
outlet,
a resilient diaphragm disposed in the chamber and constrainable in
accordance with the pressure of the fluid in the chamber,
means for removably supporting the housing on the pump,
means disposed on the pump for adjustably setting the particular
limits for the pressure of the fluid flowing through the chamber,
and
means responsive to the constraint of the diaphragm and the
adjustable setting of the particular limits for providing an output
indication when the pressure of the fluid in the chamber has
reached such particular limits.
37. The combination set forth in claim 36 wherein
the indicating means includes a pivotable member and the member is
coupled to the diaphragm to receive a force in accordance with the
constraint of the diaphragm.
38. In combination for converting a pump into a controller for
controlling within particular limits the pressure of fluid
introduced from a source to a patient,
a pump for directing fluid from the source under pressure, the pump
including a casing having a receptacle,
a housing removably disposed within the casing for receiving the
fluid directed from the source by the pump and for directing the
fluid to the patient,
resilient means included within the housing for constraint in
accordance with the pressure of the fluid in the housing.
a knob extending externally from the pump casing and adjustable in
position from a position external to the pump casing to control
within particular limits the pressure of the fluid within the
housing, and
means operatively coupled to the resilient means and the knob for
providing an output indication when the resilient means have
received a particular constraint dependent upon the setting of the
adjustable knob.
39. The combination set forth in claim 38, including,
resilient detent means in the casing for removably holding the
housing, and
detent means on the housing for cooperation with the resilient
detent means in the casing to provide a removable retention of the
housing by the casing.
40. The combination set forth in claim 39,
there being a socket in the casing for receiving the housing, the
resilient detent means being disposed in the socket.
Description
This invention relates to apparatus for use with a pump for
controlling the pressure introduced from the pump to a receiver
such as a patient. More particularly, the invention relates to
apparatus for controlling the pressure of the fluid introduced from
a pump to a receiver such as a patient to assure that the pressure
of the fluid introduced to the patient is within selected
limits.
Various instrumentalities have been provided in recent years for
introducing fluid to a patient. For example, various pumps have
been provided for pumping fluid to a patient at a particular rate
on a positive basis. For example, U.S. Pat. No. 3,985,133 issued to
me, ORRIS H. FLATTEN and OSCAR E. HYMAN as joint inventors and
assigned of record to the assignee of record of this application
discloses and claims a volumetric pump which introduces a
controlled amount of fluid at a pre-selected rate to a patient.
Although pumps are advantageous in that they introduce fluid to a
patient on a positive basis, pumps occasionally offer difficulties
in that they may introduce the fluid to the patient at pressures
greater than the pressures which would ordinarily be considered
desirable. This is particularly true when fluids are introduced to
infants or the elderly.
Controllers have also been provided for introducing fluid to a
patient on a gravitational basis. Such controllers have been
advantageous in that they operate at the relatively low pressures
which are indicated for infants and the elderly. However,
controllers have been disadvantageous until now in that they have
not provided for the flow of controlled amounts of fluid at
pre-selected rates to a patient by a positive displacement of
fluid.
Until now, no one has provided an instrument with the advantages of
both a pump and a controller. Specifically, no one has provided a
unit which introduces a controlled amount of fluid to a patient at
a low and pre-selected pressure and at a pre-selected rate by a
positive displacement of such fluid. No one has specifically
provided apparatus which is able to operate with any type of pump
to provide such advantages. Considerable efforts have been devoted
to providing such a unit but such efforts have not been entirely
fruitful.
This invention provides a unit with the advantages of both a pump
and a controller. The invention provides the advantages of a
pump--actually, any kind of pump--by producing a flow of fluid at a
controlled rate by a positive displacement of such fluid. The
invention provides the further advantages of a controller by
producing the flow of fluid at the low pressures which are
indicated even for infants and the elderly.
The invention is also advantageous in providing a disposable
cassette which is releasably coupled to a pump to convert the
operation of the pump into the operation of a controller. The
cassette is advantageous in that all of the fluid flows through the
disposable cassette. In this way, each individual cassette can be
used for a different patient and can then be removed from the pump
and can be replaced by a new cassette when a different patient is
treated or a different treatment is applied to the same
patient.
In one embodiment of the invention, a disposable cassette is
provided with a housing having detent means for a releasable
engagement with detent means on a pump. The cassette includes
conduit means defining inlet and outlet lines and a chamber between
the lines. The inlet line receives fluid from the pump and the
outlet line passes the fluid to a patient. Resilient means such as
a diaphragm are disposed at a particular position in the chamber
and are extendable in accordance with the pressure of the fluid in
the chamber. An activating arm is captured in the cassette for
movement in accordance with the extension of the diaphragm.
The activating arm may produce the operation of a sensor when the
actuating arm has moved through a particular distance. The sensor
may be included in a unit forming a part of the pump or it may be
provided as a separate unit. When the unit forms a part of the
pump, the actuating arm in the cassette may extend a resilient
diaphragm on the face of the pump in accordance with the movements
of the arm. This resilient diaphragm may in turn actuate a flag in
accordance with the extension of the diaphragm. When the flag has
been moved through a particular distance, it causes the sensor to
be energized. The particular pressure necessary to move the flag
through the particular distance may be adjusted by manually
adjusting a knob. In this way, the adjustment of the knob controls
the fluid pressure at which the sensor becomes energized.
In the drawings:
FIG. 1 is a sectional view, partially schematic, of a pump and of
one embodiment of apparatus constituting this invention for
operating with the pump to control the pressure of fluid from the
pump;
FIG. 2 is a sectional view similar to that shown in FIG. 1 but with
the apparatus in position for discontinuing the operation of the
pump;
FIG. 3 is an enlarged fragmentary elevational view of sensors
included in the apparatus of FIGS. 1 and 2;
FIG. 4 is a sectional view, partially schematic, of another
embodiment of apparatus constituting this operation for operating
with a pump to control the pressure of fluid from the pump; and
FIG. 5 is a perspective view of the embodiment shown in FIG. 4.
In the embodiment of the invention shown in FIGS. 1 through 3, a
pump generally indicated at 10 is provided for pumping fluid at a
controlled rate to a patient 14 on a positive basis. The pump 10
may be a volumetric pump such as disclosed and claimed in U.S. Pat.
No. 3,985,133. Such a pump is advantageous because it provides a
flow of a pre-selected volume of fluid at a precise rate to a
patient. However, any other type of pump may also be used.
U.S. Pat. No. 3,985,133 also discloses a disposable cassette for
use with the pump. FIG. 1 shows the pump and the disposable
cassette in broken lines.
A disposable cassette generally indicated at 12 is coupled to the
disposable cassette in the pump 10 to receive fluid from the
disposable cassette in the pump and pass the fluid to the receiver
such as the patient 14. When the pressure of the fluid in the
cassette 12 rises through a particular magnitude dependent upon the
setting of a knob 64, sensing apparatus generally indicated at 16
becomes operative to discontinue the operation of the pump. In this
way, the pressure of the fluid introduced to the patient is
controlled within pre-selected limits.
The cassette 12 is shown in some detail in FIGS. 1 and 2. The
cassette 12 includes a housing 20 having detent means such as
tongues 22 disposed externally on opposite sides of the housing.
The housing 20 is shaped to define conduit means including an inlet
line 24, an outlet line 26 and a chamber 28 between the inlet and
outlet lines. The chamber 28 communicates with the inlet line 24
and the outlet line 26.
Resilient means such as a diaphragm 30 is stretched across the
chamber 28 between opposite sides of the housing 20. An actuatable
arm 32 rests on the diaphragm and extends upwardly from the
diaphragm through an aperture or opening 34 in the housing. In this
way, the arm 32 is captured by the aperture 34. The arm 32 is
disposed in cooperative relationship with a reinforcement 33 which
extends from the diaphragm. The aperture or opening 34 communicates
with a passage 35 which has a dimension converging towards the
relatively narrow dimensions of the aperture or opening 34.
When the sensing apparatus 16 is included in the pump, the arm 32
engages resilient means such as a diaphragm 36 on the face of the
pump 10. The diaphragm 36 may have a construction similar to that
of the diaphragm 30. The diaphragm 36 supports an arm 38 which
extends upwardly through a guide aperture 40 in a housing 42 so as
to be guided for movement only in a vertical direction. A
constrained spring 43 is disposed between the housing 42 and a
member 45 seated against the diaphragm 36. A flag 44 is carried at
the upper end of the arm 38 and is pivotable at one end on a pin 46
as a fulcrum. The flag 44 carries a light source 48.
A pair of bracket members 50 are supported on the housing 42.
Spring members 52 are supported between the housing 42 and the
bracket members 50. The spring members 52 are provided with spring
arms 54 which include detent means 56 for co-operating with the
detent means 22 on the disposable cassette to hold the cassette in
releasable relationship.
A lever arm 60 extends through a threaded aperture in one of the
bracket members 50. The lever arm 60 receives the knob 64, which is
manually rotatable to adjust the vertical positioning of the lever
arm 60. At its upper end, the lever arm 60 engages the free end of
a spring arm 70, the other end of which is attached to the pump
housing 42. A bracket 74 is attached to the housing 42 as by a
nut-and-bolt arrangement 76. The bracket 74 carries a photo sensor
78.
When operative, the pump 10 introduces fluid to the inlet line 24.
This fluid flows through the chamber 28 and the outlet line 26 to
the patient 14. The maximum pressure of this fluid is dependent
upon the setting of the knob 64.
It occasionally happens that the outlet line 26 may become
occluded. At such times, the fluid in the outlet line 26 rises into
the chamber 28. When this back-up of fluid in the outlet line 26
has occurred sufficiently, the fluid in the chamber presses against
the diaphragm 30 and forces the diaphragm upwardly. The diaphragm
30 in turn acts upon the arm 32 to force the arm upwardly.
The diaphragm 36 translates the movement of the arm 32 into a
corresponding movement of the arm 38. This produces a corresponding
pivotal movement of the flag 44 about the pin 46 as a fulcrum. When
the flag 44 has moved through a particular distance dependent upon
the setting of the knob 64, the light source 48 becomes aligned
with the photocell 78. This causes the photocell 78 to become
energized and produces a signal for interrupting the operation of
the pump 10.
The particular fluid pressure for energizing the photocell 78 can
be manually adjusted by rotating the knob 64. This causes the lever
arm 60 to be adjusted vertically in position. The adjustment in the
vertical position of the lever arm 60 in turn produces adjustments
in the pivotal position of the spring arm 70. This in turn produces
adjustments in the position at which the light source 48 becomes
level with the photocell 78 to energize the photocell.
The apparatus described above has certain important advantages. It
provides for a flow of fluid from a pump to a patient at controlled
and pre-selected pressures dependent upon the setting of the knob
64. If the pressures of the fluid from the pump should increase
above such controlled and pre-selected limits, the apparatus
instantaneously senses such increases in the fluid pressure beyond
such controlled and safe limits and causes an output signal to be
produced for interrupting the operation of the pump.
The apparatus described above also has other important advantages.
For example, it provides a cassette which is easily and releasably
coupled to the pump. Furthermore, the flow of fluid from the pump
to the patient is only through the cassette. In this way, a
different cassette can be substituted every time that a different
patient is to receive the introduction of fluid or the same patient
is to receive a different fluid. By providing such an arrangement,
the pump can be easily adapted to provide fluid to a patient at
relatively low levels of pressure without requiring that the pump
be cleaned or sterilized after each use.
The apparatus constituting this invention also has other
advantages. In addition to providing the disposable cassette 12, it
provides all of the other elements within the pump housing 42.
Furthermore, the diaphragm 36 is disposed at the face of the pump.
In this way, the diaphragm 36 helps to seal the pump and also
translates the pressure of the fluid on the diaphragm 30 into a
corresponding pivotal movement of the flag 44. Although all of the
components other than those in the cassette 12 are disposed in the
pump housing 42, it will be appreciated that these components can
also be disposed in a housing which is separate from the pump.
FIGS. 4 and 5 illustrate another embodiment of the invention. In
this embodiment, a cam 100 rotatable on a fulcrum 102 is included.
The cam includes a finger 104 for contacting a leaf spring 106, the
leaf spring being attached at one end to a housing 108 by a screw
or protuberance 110. The cam 100 is shaped to move the finger 104
in a direction towards the screw or protruberance 110 in accordance
with rotary movements of the cam in a clockwise direction and to
move the finger in a direction away from the screw in accordance
with rotary movements of the cam in a counter-clockwise direction.
The cam 100 is manually rotatable by a knob 112.
The spring 106 carries a flag 114 at the end opposite the screw
110. The flag 114 may interrupt the light from a light source 116
to a sensor 118 when it has moved upwardly through a particular
distance. The force required to move the flag 114 upwardly through
this particular distance is dependent upon the setting of the cam
100 since this setting controls the length of the torque arm
between the finger 104 and the flag. In this way, the setting of
the cam 100 controls the fluid pressure at which the light to the
sensor 118 becomes interrupted.
Although this application has been disclosed and illustrated with
reference to particular applications, the principles involved are
susceptible of numerous other applications which will be apparent
to persons skilled in the art. The invention is, therefore, to be
limited only as indicated by the scope of the appended claims.
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