U.S. patent application number 11/157108 was filed with the patent office on 2006-02-09 for peristaltic pump head and tube holder.
Invention is credited to Terence Donald Bannister, David John Michael Gibson.
Application Number | 20060029506 11/157108 |
Document ID | / |
Family ID | 32678108 |
Filed Date | 2006-02-09 |
United States Patent
Application |
20060029506 |
Kind Code |
A1 |
Gibson; David John Michael ;
et al. |
February 9, 2006 |
Peristaltic pump head and tube holder
Abstract
A tube holder for use with a peristaltic pump includes a housing
having a recess for receipt of a pump rotor and a tube race around
the recess. The tube race has a first race part and a second race
part, a first tube inlet into the first race part and a first tube
outlet from the first race part, a second tube inlet into the
second race part and a second tube outlet from the second race
part. The tube is insertable in the tube race by movement in a
substantially orthogonal direction relative to the tube race so
that it extends in through the first tube inlet, around the first
race part, out through the first tube outlet, in through the second
tube inlet, around the second race part, and out through the second
tube outlet.
Inventors: |
Gibson; David John Michael;
(Wellington, NZ) ; Bannister; Terence Donald;
(Wellington, NZ) |
Correspondence
Address: |
DANN, DORFMAN, HERRELL & SKILLMAN
1601 MARKET STREET
SUITE 2400
PHILADELPHIA
PA
19103-2307
US
|
Family ID: |
32678108 |
Appl. No.: |
11/157108 |
Filed: |
June 20, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/NZ03/00286 |
Dec 22, 2003 |
|
|
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11157108 |
Jun 20, 2005 |
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Current U.S.
Class: |
417/474 ;
417/476 |
Current CPC
Class: |
F04B 43/1253
20130101 |
Class at
Publication: |
417/474 ;
417/476 |
International
Class: |
F04B 43/08 20060101
F04B043/08; F04B 43/12 20060101 F04B043/12 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 20, 2002 |
NZ |
523300 |
Claims
1. A container holding at least one fluid for dispensing by a
peristaltic pump, the container comprising a plurality of discrete
magnetic or magnetisable areas in predetermined positions on the
container to identify the container, which magnetic or magnetisable
areas (once magnetised) are configured for detection by a pump
assembly having a plurality of sensors in predetermined positions
corresponding to the positions of the magnetic or magnetisable
areas.
2. A container as claimed in claim 1, wherein the container is a
flexible container having a reservoir holding fluid and comprising
a tube holder directly connected to the flexible container, the
tube holder having a tube race around a tapered aperture or recess
configured for receipt of a tapered rotor of a peristaltic pump
head, and a tube connector configured for connection to a
resiliently flexible tube and in fluid communication with the
reservoir, which tube holder can be brought into operable
connection with the pump head to occlude fluid through a tube
connected to the tube connector and extending around the tube race
to dispense fluid from the container; and wherein the magnetic or
magnetisable areas are located on the tube holder.
3. A container as claimed in claim 2, comprising a resiliently
flexible tube connected to the tube connector and extending around
the tube race.
4. A container as claimed in claim 2, wherein the flexible
container comprises a plurality of reservoirs sealed from one
another, and the tube holder comprises a corresponding number of
tube races so that the contents of the reservoirs can be
independently dispensed via respective tubes
5. A container as claimed in claim 2, wherein the tube race has a
first race part around one part of the recess and a second race
part around another part of the recess, a first tube inlet into the
first race part and a first tube outlet from the first race part, a
second tube inlet into the second race part and a second tube
outlet from the second race part; the tube being insertable in the
tube race by movement in a direction substantially orthogonal to
the tube race so that it extends in through the first tube inlet,
around the first race part, out through the first tube outlet, in
through the second tube inlet, around the second race part, and out
through the second tube outlet.
6. A container as claimed in claim 5, comprising a lip or
projection between the first outlet and second inlet, behind which
the respective tube can be located to maintain the tube in position
within the tube race.
7. A container as claimed in claim 4, wherein the container
comprises a neck portion and two separate reservoir portions in a
Y-configuration.
8. A container as claimed in claim 2, wherein the tube holder
comprises at least one mounting boss which is located in an
aperture in a neck of the container.
9. A container as claimed in claim 8, wherein an aperture extends
through the mounting boss and into a spigot which comprises the
tube connector to which a respective tube is connected, such that
the tube is in fluid communication with a respective reservoir.
10. A container as claimed in claim 1, wherein the container is a
flexible container having a reservoir holding fluid and comprising
a tube holder directly connected to the flexible container, the
tube holder having a tube race around a tapered aperture or recess
configured for receipt of a tapered rotor of a peristaltic pump
head, and a resiliently flexible tube in fluid communication with
the reservoir and extending around the tube race, so that the tube
holder can be brought into operable connection with the pump head
to occlude fluid through the tube extending around the tube race;
and wherein the magnetic or magnetisable areas are located on the
tube holder.
11. A container as claimed in claim 10, wherein the flexible
container comprises a plurality of reservoirs sealed from one
another, and the tube holder comprises a corresponding number of
tube races so that the contents of the reservoirs can be
independently dispensed via respective tubes.
12. A container as claimed in claim 10, wherein the tube race has a
first race part around one part of the recess and a second race
part around another part of the recess, a first tube inlet into the
first race part and a first tube outlet from the first race part, a
second tube inlet into the second race part and a second tube
outlet from the second race part; the tube being insertable in the
tube race by movement in a direction substantially orthogonal to
the tube race so that it extends in through the first tube inlet,
around the first race part, out through the first tube outlet, in
through the second tube inlet, around the second race part, and out
through the second tube outlet.
13. A container as claimed in claim 12, comprising a lip or
projection between the first outlet and second inlet, behind which
the respective tube can be located to maintain the tube in position
within the tube race.
14. A container as claimed in claim 11, wherein the container
comprises a neck portion and two separate reservoir portions in a
Y-configuration.
15. A container as claimed claim 10, wherein the tube holder
comprises at least one mounting boss which is located in an
aperture in a neck of the container.
16. A container as claimed in claim 15, wherein an aperture extends
through the mounting boss and into a spigot which comprises a tube
connector to which a respective tube is connected, such that tube
is in fluid communication with a respective reservoir.
17. A container as claimed in claim 1, wherein the plurality of
magnetic areas are provided by magnets.
18. A container as claimed in claim 1, wherein the plurality of
magnetisable areas are provided by one or more strips of material,
discrete part(s) of which can been magnetised.
19. A container as claimed in claim 1, wherein the plurality of
magnetisable areas are provided by a plurality of items of a
material which has no magnetic properties until magnetised.
20. The combination of a container as claimed in claim 1 and a pump
assembly comprising a plurality of sensors in predetermined
positions corresponding to the positions of the magnetic or
magnetisable areas, the sensors configured to sense whether the
corresponding positions are magnetic or magnetised when the
container is in close proximity or contact with the pump
assembly.
21. The combination as claimed in claim 20, wherein there are a
greater number of sensors than there are magnetic or magnetised
areas on the container.
22. The combination as claimed in claim 20, wherein the pump
assembly further comprises a microprocessor and a memory, which
microprocessor is configured to determine from the sensors the
numbers and positions of the magnetic or magnetised areas, and to
then access the memory to determine the substance(s) in the
container.
23. The combination as claimed in claim 22, wherein the
microprocessor is configured to activate a software routine
associated with the substance(s) of the container if the number and
position of the magnetic or magnetised areas corresponds to a value
stored in the memory.
24. The combination as claimed in claim 23, wherein the software
routine determines when pump(s) of the pump assembly should be
actuated, for how long, and in which combination.
25. The combination as claimed in claim 20, wherein the sensors are
Hall Effect sensors.
Description
FIELD OF THE INVENTION
[0001] The invention relates to a peristaltic pump head for pumping
fluids, and to a tube holder for use with a peristaltic pump
head.
BACKGROUND OF TE INVENTION
[0002] A large number of applications require the pumping of
fluids. Standard pumps result in the fluid coming into contact with
the pumping apparatus, thereby risking contamination of the fluid.
Peristaltic pumps operate by occluding a tube containing the fluid,
so that the fluid only comes into contact with the interior of the
tube, and not the pumping head of other pumping components.
[0003] One problem faced with conventional peristaltic pumps is
maintaining the tube in a desired position within the tube race, as
if the tube moves with movement of the pumping head, the fluid will
not be pumped efficiently.
[0004] Another issue with conventional peristaltic pumps is
maintaining correct alignment between the pump head and the tube in
the raceway, and maintaining the desired pressure on the tube for
consistent fluid pumping.
[0005] It is an object of at least a preferred embodiment of the
present invention to provide a peristaltic pump head and/or tube
holder which address at least one of the issues outlined above
and/or which at least provides the public with a useful choice.
SUMMARY OF THE INVENTION
[0006] In accordance with a first aspect of the present invention,
there is provided a tube holder for use with a peristaltic pump,
the tube holder including: [0007] a housing having a recess for
receipt of a pump rotor, a tube race for receipt of a tube around
the recess and having a first race part around one part of the
recess and a second race part around another part of the recess, a
first tube inlet into the first race part and a first tube outlet
from the first race part, a second tube inlet into the second race
part and a second tube outlet from the second race part; [0008] the
tube being insertable in the tube race by movement in a
substantially orthogonal direction relative to the tube race so
that it extends in through the first tube inlet, around the first
race part, out through the first tube outlet, in through the second
tube inlet, around the second race part, and out through the second
tube outlet.
[0009] The first tube outlet and second tube inlet are suitably
configured such that the tube can exit the housing between the
first outlet and second inlet.
[0010] The first tube outlet and second tube inlet may be in
communication with a recess or groove which is separate to the tube
race, but which is located within the housing.
[0011] The housing advantageously includes a lip or projection
between the first outlet and the second inlet, behind which the
tube can be located to maintain the tube in position within the
tube race.
[0012] The recess may be tapered for receipt of a tapered pump
rotor. Preferably, each tube race part is defined by a channel or
groove extending inwardly from a respective tube inlet and tube
outlet. The grooves suitably extend part way around the recess.
Preferably, the recess provides surfaces against which the tube is
occluded to pump fluid therethrough in use.
[0013] The tube holder may be a one-piece article.
[0014] The tube holder may be provided in combination with a pump
head having a tapered rotor which is received in the recess of the
tube holder, such that actuation of the pump head causes fluid to
be pumped through a tube in the tube holder by occlusion of the
tube.
[0015] The tube is suitably resiliently flexible so that it returns
substantially to its original shape following occlusion, to thereby
suck fluid through the tube.
[0016] Preferably, the rotor is axially biased towards its tapered
end, such that the pump rotor and tube race are self-adjusting, to
maintain a desired pressure on a tube in the tube race during
pumping. The rotor may be axially biased by a compression
spring.
[0017] The pump head preferably includes a stop to limit the axial
movement of the rotor relative to the housing. The stop is suitably
in the form of an annular lip on the rotor.
[0018] Preferably, the pump head includes a transmission mechanism
to transmit motive power from a power source to the rotor, and the
base of the tapered rotor includes a plurality of gear teeth which
engage with a gear of the transmission mechanism, with the gear
teeth of the rotor and the teeth of the gear of the transmission
mechanism of sufficient length to remain engaged during axial
movement of the rotor. The gear teeth of the rotor are suitably
elongate and longer than the teeth of the gear.
[0019] Part of the rotor may be substantially conical or
frustoconical, and advantageously has a plurality of rollers
rotatably mounted thereon which are configured to occlude the tube
in use. The rollers are suitably substantially frustoconical in
configuration, with their tapered ends directed towards the tapered
end of the rotor. The rollers are suitably mounted for rotation
with axes which taper toward the tapered end of the rotor.
[0020] The rotor preferably includes a main body part and a head
part, with the rollers mounted for rotation in a recess or recesses
between the main body part and the head part.
[0021] The tube holder and pump head may be fully separable from an
operable configuration in which the rotor is located in the recess
of the tube holder and configured to pump fluid through a tube to a
loading configuration in which the tube may be loaded into the tube
race.
[0022] In accordance with a second aspect of the present invention,
there is provided a method of loading a tube into a tube holder
including: [0023] providing a tube holder having a housing having a
recess for receipt of a pump rotor, a tube race for receipt of a
tube around the recess and having a first race part around one part
of the recess and a second race part around another part of the
recess, a first tube inlet into the first race part and a first
tube outlet from the first race part, a second tube inlet into the
second race part and a second tube outlet from the second race
part; [0024] providing a tube; and [0025] moving the tube in a
substantially orthogonal direction relative to the tube race such
that it extends in through the first tube inlet, around the first
race part, out through the first tube outlet, in through the second
tube inlet, around the second race part, and out through the second
tube outlet.
[0026] The tube holder may be as outlined in the first aspect
above.
[0027] The tube holder preferably includes a retainer which is in
the form of a projection or lip between the first outlet and the
second inlet, and the method may further include pulling the
installed tube in a direction away from the projection or lip so
that the tube is maintained in position within the tube race with
part of the tube located behind the projection or lip.
[0028] The method suitably includes bringing the tube holder into
engagement with a pump head to provide the combination of a tube
holder and a pump head, and so that the rotor so that the pump head
is located in the recess in the tube holder.
[0029] The combination may be as outlined above.
[0030] In accordance with a third aspect of the present invention,
there is provided the combination of a peristaltic pump head having
a tapered pump rotor which is rotatable about an axis of rotation,
and a tube holder having a recess for receipt of the tapered end of
the rotor, the tube holder having a tube race configured for
receipt of a tube for pumping of a fluid by movement of the rotor,
the tube race including a plurality of separate race parts around
the recess defined by a plurality of apertures or recesses such
that the tube can exit and re-enter the tube race
[0031] The tube is preferably insertable into the tube race without
separating the tube holder from the pump head.
[0032] Preferably, the tube holder and pump head are movable from
an operable configuration in which the rotor is located in the
recess of the tube holder and configured to pump fluid through a
tube to a loading configuration in which the tube may be loaded
into the tube race. Advantageously, the tube holder and pump head
are fully separable.
[0033] In a preferred embodiment, the tube holder has a housing, a
first tube race part around one part of the recess defined by a
first tube inlet aperture and a first tube outlet aperture, and a
second tube race part around another part of the recess defined by
a second tube inlet aperture and a second tube outlet aperture,
such that movement of a tube threaded therethrough in the axial
direction of the rotor is minimised or prevented by the
apertures.
[0034] The tube holder may be as outlined in the first aspect
above.
[0035] The tube is suitably resiliently flexible so that it returns
substantially to its original shape following occlusion, to thereby
suck fluid through the tube.
[0036] The rotor is suitably axially biased towards its tapered
end, such that the pump rotor and tube race are self-adjusting, to
maintain a desired pressure on a tube in the tube race during
pumping.
[0037] Preferably, the rotor is axially biased by a compression
spring.
[0038] The pump head preferably includes a stop to limit the axial
movement of the rotor relative to the housing. The stop is suitably
in the form of an annular lip on the rotor.
[0039] The pump head preferably includes a transmission mechanism
to transmit motive power from a power source to the rotor, and the
base of the tapered rotor preferably includes a plurality of gear
teeth which engage with a gear of the transmission mechanism, with
the gear teeth of the rotor and the teeth of the gear of the
transmission mechanism of sufficient length to remain engaged
during axial movement of the rotor. The gear teeth of the rotor are
suitably elongate and longer than the teeth of the gear.
[0040] Preferably, the tapered part of the rotor is substantially
conical or frustoconical, and has a plurality of rollers rotatably
mounted thereon which are configured to occlude the tube in
use.
[0041] The rollers are suitably substantially frustoconical in
configuration, with their tapered ends directed towards the tapered
end of the rotor. The rollers may be mounted for rotation with axes
which taper toward the tapered end of the rotor.
[0042] Preferably, the rotor includes a main body part and a head
part, with the rollers mounted for rotation in a recess or recesses
between the main body part and the head part.
[0043] In accordance with a fourth aspect of the present invention,
there is provided a peristaltic pump head, including: [0044] a
housing; [0045] a transmission mechanism for transmitting motive
force from a drive mechanism to a rotor, and including a gear with
a plurality of teeth; [0046] a tapered pump rotor mounted for
rotation about an axis of rotation within the housing and which is
axially biased towards its tapered end, the base of the tapered
pump rotor including gear teeth which engage with the teeth of the
gear of the transmission mechanism, wherein the gear teeth of the
rotor and the teeth of the gear of the transmission mechanism are
of sufficient length to remain engaged during axial movement of the
rotor relative to the housing.
[0047] The gear teeth of the rotor are suitably elongate and longer
than the teeth of the gear.
[0048] Preferably, the transmission mechanism includes a plurality
of gears.
[0049] The rotor may be axially biased by a compression spring.
[0050] The pump head preferably includes a stop to limit the axial
movement of the rotor relative to the housing. The stop may be in
the form of an annular lip on the rotor.
[0051] In accordance with a fifth aspect of the present invention,
there is provided a kit of parts for assembling a peristaltic pump
head assembly, including: [0052] a rotor and a housing having first
and second housing parts and configured for receipt of the rotor;
which rotor may be maintained in the housing by snapping the
housing parts together such that the pump head assembly can be
assembled without the use of adhesives or separate fasteners.
[0053] Advantageously, the rotor is provided in kit form, and
includes a main body part, a head part and at least one roller,
which rotor may be assembled by snapping the main body part and
head part together to sandwich the roller(s) therebetween.
[0054] Preferably, the rotor is tapered and is mountable for
rotation about an axis of rotation within the housing and to be
axially biased towards its tapered end, and wherein the rotor
includes a stop to limit the axial movement of the rotor relative
to the housing when assembled.
[0055] The kit may include a compression spring to axially bias the
rotor relative to the housing.
[0056] A base of the tapered rotor preferably includes gear teeth,
and the kit includes a gear with a plurality of teeth to transmit
motive force from a drive mechanism to the rotor, the gear teeth of
the rotor and the teeth of the gear being of sufficient length to
remain engaged during axial movement of the rotor relative to the
housing once assembled.
[0057] All components are preferably made of a plastics material.
Alternatively, all components other than the spring may be made of
a plastics material.
[0058] In accordance with a sixth aspect of the present invention,
there is provided a flexible container having a reservoir for
holding fluid and including a tube holder directly connected to the
flexible container, the tube holder having a tube race around a
tapered aperture or recess configured for receipt of a tapered
rotor of a peristaltic pump head, and a tube connector configured
for connection to a resiliently flexible tube and in fluid
communication with the reservoir, which tube holder can be brought
into operable connection with the pump head to occlude fluid
through a tube connected to the tube connector and extending around
the tube race to dispense fluid from the container.
[0059] The container preferably includes a resiliently flexible
tube connected to the tube connector and extending around the tube
race.
[0060] In accordance with a seventh aspect of the present
invention, there is provided a flexible container having a
reservoir for holding fluid and including a tube holder directly
connected to the flexible container, the tube holder having a tube
race around a tapered aperture or recess configured for receipt of
a tapered rotor of a peristaltic pump head, and a resiliently
flexible tube in fluid communication with the reservoir and
extending around the tube race, so that the tube holder can be
brought into operable connection with the pump head to occlude
fluid through the tube extending around the tube race.
[0061] The flexible container of the sixth or seventh aspect may
include a plurality of reservoirs sealed from one another, and the
tube holder may include a corresponding number of tube races so
that the contents of the reservoirs can be independently dispensed
via respective tubes.
[0062] Preferably, the tube race(s) has/have a first race part
around one part of the recess and a second race part around another
part of the recess, a first tube inlet into the first race part and
a first tube outlet from the first race part, a second tube inlet
into the second race part and a second tube outlet from the second
race part; the respective tube being insertable in the respective
tube race by movement in a direction substantially orthogonal to
the tube race so that it extends in through the first tube inlet,
around the first race part, out through the first tube outlet, in
through the second tube inlet, around the second race part, and out
through the second tube outlet.
[0063] The tube holder preferably includes a lip or projection
between the first outlet(s) and second inlet(s), behind which the
respective tube can be located to maintain the tube in position
within the tube race.
[0064] The container preferably includes a neck portion and two
separate reservoir portions in a Y-configuration.
[0065] The tube holder may include at least one mounting boss which
is located in an aperture in a neck of the container.
[0066] An aperture may extend through the mounting boss(es) and
into a spigot(s) which comprise(s) the tube connector to which a
respective tube is connected, such that tube(s) is/are in fluid
communication with a respective reservoir.
[0067] In accordance with an eighth aspect of the present
invention, there is provided a container holding at least one fluid
for dispensing by a peristaltic pump, the container including a
plurality of magnetic or magnetisable areas in predetermined
positions on the container to identify the container, which
magnetic or magnetisable areas (one magnetised) are configured for
detection by a pump assembly having a plurality of sensors in
predetermined positions corresponding to the positions of the
magnetic or magnetisable areas.
[0068] The may be of the type outlined in the sixth or seventh
aspects above, and the magnetic or magnetisable areas may be
located on the tube holder.
[0069] The plurality of magnetic areas may be provided by magnets.
Alternatively, the plurality of magnetisable areas may be provided
by one or more strips of material, discrete part(s) of which can
been magnetised. As another alternative, the plurality of
magnetisable areas may be provided by a plurality of items of a
material which has no magnetic properties until magnetised.
[0070] The container may be in combination with a pump assembly
including a plurality of sensors in predetermined positions
corresponding to the positions of the magnetic or magnetisable
areas, the sensors configured to sense whether the corresponding
positions are magnetic or magnetised when the container is in close
proximity or contact with the pump assembly.
[0071] There may be a greater number of sensors than there are
magnetic or magnetised areas on the container.
[0072] The pump assembly may further include a microprocessor and a
memory, which microprocessor is configured to determine from the
sensors the numbers and positions of the magnetic or magnetised
areas, and to then access the memory to determine the substance(s)
in the container. The microprocessor may be configured to activate
a software routine associated with the substance(s) of the
container if the number and position of the magnetic or magnetised
areas corresponds to a value stored in the memory. The software
routine preferably determines when pump(s) of the pump assembly
should be actuated, for how long, and in which combination.
[0073] The sensors may be Hall Effect sensors.
[0074] The invention consists in the foregoing and also envisages
constructions of which the following gives examples only.
BRIEF DESCRIPTION OF THE DRAWINGS
[0075] Preferred embodiments of the present invention will be
described by way of example only with reference to the accompanying
figures in which:
[0076] FIG. 1 is an overhead perspective view of a preferred
embodiment peristaltic pump head in combination with a tube
holder;
[0077] FIG. 2 is a plan view of the pump head and tube holder of
FIG. 1;
[0078] FIG. 3 is a side sectional view of the pump head and tube
holder along line 3-3 of FIG. 2, in a pumping configuration;
[0079] FIG. 4 is an overhead perspective sectional view of the pump
head and tube holder along line 3-3 of FIG. 2, before the tube
holder is moved into the pumping configuration;
[0080] FIG. 5 is a side sectional view of the pump head along line
3-3 of FIG. 2, with the tube holder removed;
[0081] FIG. 6 is an overhead perspective view of a first preferred
embodiment tube holder for use with the pump head of FIG. 1;
[0082] FIG. 7 is an underside perspective view of the tube holder
of FIG. 6;
[0083] FIG. 8 is an exploded overhead perspective view of the tube
holder of FIG. 6;
[0084] FIG. 9 is an exploded underside perspective view of the tube
holder of FIG. 6;
[0085] FIG. 10 is an overhead perspective view of a second
preferred embodiment tube holder for use with the pump head of FIG.
1;
[0086] FIG. 11 is an underside perspective view of the tube holder
of FIG. 10;
[0087] FIG. 12 is a plan view of the tube holder of FIG. 10;
[0088] FIG. 13 is an underside view of the tube holder of FIG.
10;
[0089] FIG. 14 is an overhead perspective view of a pump assembly
including three pump heads of FIGS. 1 to 4;
[0090] FIG. 15 is an overhead perspective view of a preferred
embodiment tube holder for use with the pump assembly of FIG.
14;
[0091] FIG. 16 is a perspective view of a sachet which will be
connected to the tube holder of FIG. 15;
[0092] FIG. 17 is an overhead perspective view of the tube holder
of FIG. 15 connected to a flexible container in the form of a
sachet;
[0093] FIG. 18 is an overhead perspective view of the tube holder
of FIG. 17, with tubes fed around the tube holding portions;
[0094] FIG. 19 is an overhead perspective detail view showing the
interconnection between one of the tubes and the sachet;
[0095] FIG. 20 shows the sachet and tube holder of FIG. 19 being
brought into connection with the pump assembly of FIG. 14;
[0096] FIG. 21 shows the sachet and tube holder of FIG. 19
connected to the pump assembly of FIG. 14;
[0097] FIG. 22 shows the sachet and tube holder of FIG. 17,
including magnets forming a coding system; and
[0098] FIG. 23 schematically shows a pump assembly configured to
read the coding system of the tube holder of FIG. 22.
DETAILED DESCRIPTION OF PREFERRED FORMS
[0099] With reference to FIG. 1, the peristaltic pump assembly has
a main housing 1 carrying a rotor 3, which is received in a tube
holder 105. The peristaltic pump head pumps fluid through a tube
maintained in the tube holder 105, by the rotor compressing the
tube and pushing fluid therethrough, this process known as
occlusion. Two alternative preferred tube holders will be described
below with reference to FIGS. 6-13.
[0100] As can be seen more clearly from the sectional views of
FIGS. 3 and 4, the preferred rotor 3 is tapered and more
particularly is substantially conical in configuration, with its
tapered end extending upwardly from the housing 1. The rotor 3 has
a main body part 7 and a head part 9 interconnected with the main
body part, which head part 9 is mounted for rotation on a boss 11
extending upwardly within the housing. As can be seen most clearly
in FIG. 3, in side profile the head part 9 has a curved upper
surface to enhance movement into the tube holder 105 when the
components are brought together.
[0101] The boss 11 defines the axis of rotation of the rotor 3, and
is substantially cylindrical or tubular and configured for receipt
of a pusher 13. The head of the pusher 13 is biased against the
underside of the head part 9 of the rotor by a biasing device 15,
which is most preferably a compression spring coiled around a shaft
of the pusher. The biasing device biases the rotor 13 towards its
tapered head end, and therefore towards the tube holder 105 in the
assembled configuration. A clearance is provided between the base
of the pusher 13 and the base of the boss 11, and also between the
base of the main body part 7 and the base of the housing 1. This
enables the rotor 3 to move downwardly relative to the housing
which allows it to automatically adjust within the tube holder as
will be described.
[0102] A recess is provided in the rotor between the head part 9
and the main body part 7 for receipt of a number of rollers 17. In
the preferred embodiment, three rollers are provided in an equally
spaced configuration around the central axis of the rotor. However,
it will be appreciated that the number of rollers can be varied as
desired. The rollers 17 are substantially frustoconical in
configuration, and are mounted for rotation on mounting members 19
which extend between the rotor main body part 7 and the head part
9. A corresponding number of inverted conical recesses 21 are
provided in the main body part 7 of the rotor, for receipt of the
enlarged conical bases 23 of the respective mounting members.
Smaller recesses 25 are provided in the underside of the head part
9 for receipt of the upper ends of the mounting members.
[0103] A stop, which in the embodiment shown is an annular lip 26,
extends outwardly from the main body part 7 of the rotor, which
defines the upper limit of travel of the rotor 3 within the housing
1. When the rotor is not in contact with the tube holder, the
spring 15 will bias the rotor upwardly until the lip 26 engages the
underside of the upper part of the housing 1 as shown in FIG. 5.
When the tube race 5, 105 is brought into contact with the rotor
(as will be described below) that will push the rotor downwardly
against the bias of the spring, so the lip 26 no longer engages
against the housing 1.
[0104] During assembly of the rotor 3, the mounting members 19 and
rollers 17 are mounted on the rotor main body part 7, and the head
part 9 is attached to the main body part 7 to maintain the rollers
in position in the rotor. The mounting members 19 define the axes
of rotation of the rollers 17 on the rotor, and it can be seen that
these axes taper towards the head part 9 of the rotor. The included
angles between the axes can be varied if desired.
[0105] A connector in the form of a pair of fingers 27 extend from
the base of the head part 9 and are receivable in the central
aperture of the main body part 7, so that the rotor can snap
together, thereby sandwiching the mounting members 19 and the
rollers 17 for rotation between the main body part 7 and the head
part 9. The assembled rotor can then be inserted on the pusher 13
and spring within the boss 11, and the upper and lower housing 1
parts can be snapped together. Accordingly, the entire assembly of
the housing 1, rotor 3 and gears 55, 57 can be assembled without
the use of any bolts, screws or adhesives. It is further preferred
that the engagement between the tube holder 5, 105 and rotor is
achieved without any fasteners, so the entire assembly of the pump
head and tube holder does not require the use of adhesives or
separate fasteners.
[0106] A transmission mechanism generally indicated by reference
numeral 51 is also provided in the housing for transmitting motive
force to the rotor. In the embodiment shown, the outer perimeter of
the main body part of the rotor includes a plurality of sprocket
teeth 53. The teeth 53 are engaged with teeth on an intermediate
gear 55, which in turn are engaged with the teeth of a drive gear
57. The sprocket teeth 53 around the base of the main body part are
elongate and of sufficient length that they remain in engagement
with the teeth of the intermediate gear 55 throughout the range of
axial movement of the rotor within the housing 1. An aperture 59 is
provided in the housing 1 and is aligned with the axis of rotation
of the drive gear. A shaft can extend through the aperture 59 and
engage the centre of the drive gear 57 to operably connect the
drive gear to an electric motor (not shown) or similar. As shown in
FIG. 4, coaxial apertures are provided in the housing 1 above and
below the drive gear 57, so that the shaft could enter the housing
either above or below as desired. Similarly, the housing could be
inverted so that a shaft below the housing engages the drive gear
57 from the upper aperture (orientation relative to the drawing) if
desired.
[0107] The relative numbers of teeth on the gears could be selected
to provided a desired up-speed or down-speed of the rotor relative
to the input speed as desired. More or less gears could be used.
Alternatively, an alternative transmission such as pulleys and
bands or gears and chains could be used. An electric servo motor
could be positioned within the housing 1 rather than, or in
addition to, using a transmission mechanism.
[0108] All of the components are most preferably made of a suitable
polymer plastic material, such as acetyl, ABS or similar. Such a
configuration is advantageous as it means the components can be
easily fabricated in large numbers such as by injection moulding,
the apparatus will be relatively light weight, and corrosion of the
components will not occur. It may however, be desirable to
fabricate the spring from a suitable metal such as spring steel to
provide the desired spring characteristics.
[0109] As can be seen from FIGS. 1 to 4, a tube holder 105 is
positioned above the rotor 3. That tube holder is described with
reference to FIGS. 10 to 13. Another suitable tube holder 5 is
shown in FIGS. 6 to 9. The tube holder has two parts, a base part
61 and a tube guide part 63 which together form a tube holder
housing. The tube guide part 63 and base part 61 preferably snap
together. The tube holder housing could be a unitary member if
desired. The tube guide part 63 includes a tapered frustoconical
recess 65 for receipt of the rotor 3 as shown in FIG. 3 for
example. A number of apertures 67a, 67b, 67c and 67d are spaced
around the recess and define a first tube inlet 67a, first tube
outlet 67b, second tube inlet 67c and second tube outlet 67d. The
apertures and the recess define a tube race within which the tube
extends around the recess when it is inserted in the tube
holder.
[0110] The tube race has a first race part defined by the first
tube inlet 67a, the first tube outlet 67b, and the surface of the
recess therebetween. The tube race has a second race part defined
by the second tube inlet 67c, the second tube outlet 67d, and the
surface of the recess therebetween.
[0111] As can be seen from FIG. 9, the underside of the tube guide
part 63 includes a plurality of channels aligned with the
apertures. In use, and with reference to FIGS. 6 and 9, a tube is
inserted into the housing through channel 69 and fed through the
first tube inlet aperture 67a. The tube is then extended around the
surface of the recess 65 as far as first tube outlet 67b and out
through the first tube outlet 67b, around channel 71, back into the
race through the second tube inlet 67c, around the surface of the
recess 65 as far as second tube outlet 67d, out through the second
tube outlet 67d, over the part of the tube extending inwardly
through channel 69 and back out of the housing through channel 73.
It will be appreciated that the tube could be inserted through the
housing in the other direction, ie in through channel 73 and out
through channel 69 if desired.
[0112] A transverse hole (not shown) may be provided at the
intersection of channels 69 and 73, the hole extending from top to
bottom of the tube holder. The edges where the hole meets the
channels 69 to 73 would provide a relatively sharp edge against
which the tube parts would engage to assist in gripping the tube
and maintaining it in position in the tube holder.
[0113] The portions of the tube located against the surface of the
recess 65 are occluded by the rollers 17 of the rotor 3 when the
tube holder and rotor are in the configuration shown in FIG. 3 and
the rotor is rotated. The surfaces of the recess 65 against which
the tube is seated provide occluding surfaces, with the tube being
compressed between the rollers 17 and those surfaces.
[0114] By having the tube exit and re-enter the tube race as
described above, movement of the tube in the axial direction of the
rotor during use is inhibited, as the edges of the apertures 67a,
67b, 67c and 67d prevent significant axial movement of the tube.
Further, as the rotors only act against discrete parts of the tube,
that also serves to minimise longitudinal movement of the tube as
the rotor rotates.
[0115] The rollers 17 on the rotor and the tube holder are
configured so that part of the tube is always compressed under at
least one roller, to prevent leaking of fluid from the reservoir or
backflow into the reservoir.
[0116] To provide additional stability to the tube in the holder,
the inside of the tube holder base 61 includes a number of shaped
projections 75, 77 and 79 which are located in channels 69, 71 and
73 respectively when the holder base part 61 and the guide part 63
are brought together. The projections may be sized such that there
is limited clearance between the ends of the projections and the
bases of the respective channels when the tube holder base part and
guide parts are assembled, so that the tube is slightly compressed
therebetween (such a configuration being shown in FIG. 6). In this
embodiment, the tube would need to be threaded into the guide part
before the guide part is brought into contact with the base part.
Corresponding protrusions 81 and apertures 83 are provided in the
base part and the guide part, which are an interference or snap fit
to maintain the base part and the guide part in the assembled
configuration.
[0117] However, it is not essential that the tube be slightly
compressed between the base and guide parts, as it can be
sufficiently held simply by exiting and reentering the tube race.
In the embodiment in which the tube is not compressed between the
base and guide parts, those components can be assembled before the
tube is fed into the housing.
[0118] FIGS. 10 to 13 show an alternative preferred tube holder
105. This tube holder is a unitary component, and again includes a
tapered frustoconical recess 165 for receipt of the rotor 3 as
shown in FIG. 3. Rather than using apertures to define tube inlets
and outlets, they are defined by a number of grooves. The grooves
define a first tube inlet 167a, a first tube outlet 167b, a second
tube inlet 167c and a second tube outlet 167d. The grooves and
recess define a tube race within which the tube extends around the
recess when it is inserted in the tube holder.
[0119] The tube race has a first race part defined by the first
tube inlet 167a, the first tube outlet 167b, and the surface of the
recess 165 therebetween. The tube race has a second race part
defined by the second tube inlet 167c, the second tube outlet 167d,
and the surface of the recess 165 therebetween.
[0120] The channels forming the first tube inlet 167a and second
tube outlet 167d could cross, in a similar manner to channels 69
and 73 of the embodiments of FIGS. 6 to 9. Additionally or
alternatively, the channels forming the tube inlets and outlets
could include features along their walls to improve grip on the
tube. For example, teeth or projections (not shown) could be
present along the walls of the channels to assist in gripping the
tube.
[0121] An outwardly extending projection or lip 107 is situated
between the first tube outlet 167b and the second tube inlet 167c.
The lip 107 is located above the level of the first tube outlet
167b and the second tube inlet 167c (in the orientation of FIG. 9),
and assists in maintaining the tube in the tube holder. The lip
could include a downwardly extending (in the orientation shown in
FIG. 10) projection at its distal end to assist in maintaining the
tube in the tube holder.
[0122] To load the tube into the tube holder, it is provided in a
substantially U-shaped configuration and is moved in a direction
substantially orthogonal to the tube race (ie downwardly in the
orientation of FIG. 10) such that the tube extends in through the
first tube inlet 167a, around the surface of the recess 165, out
through the second tube outlet 167b, in through the second tube
inlet 167c, around the surface of the recess 165, and out through
the second tube outlet 167d, as shown in phantom in FIG. 12. This
can be achieved in a single orthogonal movement, and can be
performed manually or by a machine.
[0123] The tube can then be pulled in the direction of first tube
inlet 167a and second tube outlet 167d such that the base of the
U-shape is located under the lip or projection 107. A wider lip or
projection 107 could be provided, and the first tube outlet 167b
and second tube inlet 167c could extend more towards the corners of
the tube holder than shown in FIG. 12 (in more of a "V" shape), to
provide a longer curved portion under the lip or projection 107
around which the tube extends when installed, to thereby assist in
maintaining the tube in position in the tube holder.
[0124] Again by virtue of the tube exiting and re-entering the tube
race, movement of the tube therein is inhibited. If desired, to
provide additional stability to the tube in the tube race, the base
of the grooves could be slightly enlarged relative to the upper
portions of the grooves so that the tube is a snap fit into the
grooves.
[0125] The portions of the tube extending around the recess 165 are
occluded by the rollers 17 of the rotor 3 when the tube holder and
rotor are in the configuration shown in FIG. 3 as the rotor is
rotated.
[0126] When the tube holder 105 is located in position on the pump
head housing 1, the outer edges of the grooves 167a-d will be
located against the surface of the housing 1.
[0127] One end of the tube will typically be fluidly connected to a
source of fluid, and the other end of the tube will typically be
fluidly connected to an apparatus for delivery of the fluid.
[0128] Either type of tube holder 5, 105 can be used in with
peristaltic pump head. In the assembled configuration of the pump
head and the tube holder, the tube holder 5, 105 may be floating
relative to the pump head housing 1, i.e. limited movement
transverse to the axial direction of the rotor will be provided, or
may be fixed relative to the housing. Limited axial movement of the
tube holder can also be provided, which is compensated for by the
biased pump head. For example, a tube holder carrier (not shown)
may be provided containing a recess within which the tube holder
can be placed, with limited axial and transverse movement of the
tube holder relative to the carrier. The components can then be
brought together so that the rotor extends through the recess in
the tube holder, to pump fluid through a tube in the tube holder.
The housing 1 could be attached to the carrier so that no movement
therebetween (but there could still be floating movement of the
tube holder), but it is preferred that some floating movement is
provided between the housing 1 and the carrier, to accommodate
misalignment between the rotor and the tube holder.
[0129] By virtue of the transverse floating of the tube holder 5,
105 and the axial bias of the rotor 3, the pump head will be self
aligning and self adjusting. The biased tapered rotor 3 will move
the tube holder 5, 105 transversely if necessary so that it is
aligned with the centre of the recess 65, 165. Further, the rotor
will automatically move axially a sufficient distance that the
rollers are located against the tube in the tube holder with a
desired force determined by the spring characteristics. Therefore,
the pressure applied to the tube by the rotor will be substantially
constant That would also occur without any transverse floating
between the tube holder and the pump head.
[0130] It is preferred that the pump head could be operable in a
forward or rearward direction, to either dispense or suck
fluid.
[0131] The tube holders are preferably made from a polymer plastics
material, such as acetyl, ABS or similar, and may be fabricated by
injection moulding for example. The pump head can be made to a
small size, with the dimensions of the main housing 1 being about
68 mm.times.25 mm.times.15 mm (at the deepest point shown), and the
dimensions of the tube holder being about 30 mm.times.25 mm.times.7
mm for example. However, the pump head is fully scalable, and could
be used to make much larger pumps. In larger pumps, the tube holder
could be modified to have a greater number of race parts, ie the
tube could be woven in and out of the housing a greater number of
times than described above.
[0132] FIG. 14 shows a pump assembly generally indicated by
reference numeral 201. The pump assembly includes a main housing
202 which includes a recess 203 containing three of the pump heads
1 described with respect to FIGS. 1 to 4. While three pump heads 1
are shown in the Figure, more or less pump heads could be provided
if desired. The pump heads are positioned so that the rotors 3 are
positioned in the recess 203, which is configured to receive a tube
holder as will be described below.
[0133] Although not shown in the Figure, the main housing also
includes an interior chamber which is covered by a cover 205. The
chamber preferably houses a drive mechanism or mechanisms such a
number of servo motors and a microprocessor for controlling the
rive mechanism(s). The housings of the pump heads 1 extend into the
interior chamber and the drive mechanism may be operably connected
to the transmission mechanism via a shaft extending through the
aperture 59 in each pump head housing for example. It is preferred
that the pump heads 1 are independently operable. The pump head
housings are preferably fixed in the pump assembly main housing 202
by fasteners or the like, so that they cannot move relative to the
pump assembly main housing 202.
[0134] FIG. 15 shows a preferred embodiment tube holder generally
indicated by reference numeral 251, for use with the pump assembly
of FIG. 15. The tube holder 251 includes a main body part 253 which
includes three tube holding portions 255a-c. The number of tube
holding portions will be selected to correspond with the number of
pump heads 1 in the pump assembly main housing 202.
[0135] Each of the tube holding portions 255a-c has generally the
same configuration as the tube holder of FIGS. 10 to 13, and
includes a tapered frustoconical recess 257 for receipt of the
rotor 3 of the respective pump head 1. Each tube race is defined by
a first tube inlet 259a, a first tube outlet 259b, a second tube
inlet 259c and a second tube outlet 259d. The tube race has a first
race part defined by the first tube inlet 259a, the first tube
outlet 259b, and the surface of the recess 257 therebetween. The
tube race has a second race part defined by the second tube inlet
259c, the second tube outlet 259d, and the surface of the recess
therebetween.
[0136] An outwardly extending projection or lip 261 is situated
between the first tube outlet 259b and the second tube inlet 259c.
The lip 261 is located above the level of the first tube outlet
259b and the second tube inlet 259c (in the orientation of FIG.
15), and assists in maintaining the tube in the tube holder.
[0137] The tube holder body 253 includes a flange 263, and a hinged
connecting member 265. The hinged connecting member 265 is movable
from the position shown in FIG. 15 wherein it is pivoted away from
the flange 263 to a position shown in FIG. 17 wherein it is in
contact with the flange 263. The flange 263 includes engagement
projections 267 with enlarged heads for engaging in recesses 269 in
the connecting member 265 when it is in the position shown in FIG.
17.
[0138] The hinged connecting member 265 is connected to a flexible
container in the form of a sachet for containing fluid to be
delivered by the pump. A suitable sachet 271 is shown in FIG. 16.
In the embodiment shown, the sachet 271 includes a neck portion 273
and two reservoir portions 275, 277 in a Y-configuration. It has
been found that by using two reservoir portions 275, 277 in the
configuration shown, a lower profile can be achieved while still
providing the desired storage volume for fluid to be administered
by the pump.
[0139] The neck portion 273 is formed with three enlarged apertures
279a-c, configured to receive corresponding mounting bosses 281a-c
on the hinged connecting member 265 of the tube holder 251. The
sachet 271 is connected to the tube holder 251 by inserting the
mounting bosses 281a-c into respective enlarged apertures 279a-c.
The sachet 271 and tube holder 251 may be maintained in connection
by adhering the bosses 281a-c in the enlarged apertures with an
adhesive or similar, or by plastic welding the components together
for example. Suitable materials for the sachet include, but are not
limited to, a flexible polymer plastic or foil. The tube holder is
preferably made from a polymer plastic.
[0140] Apertures 282a-c extend through the mounting bosses 281a-c
of the tube holder, and into corresponding spigots 283a-c which
extend towards the tube holding portions 255a-c when the connecting
member 265 is in the position shown in FIG. 17. The apertures are
in fluid communication with the interior of the sachet 271a. This
sachet differs as the interior of the sachet is divided into the
same number of independent fluid chambers as there are enlarged
apertures 279a-c in the neck. This is shown in more detail in FIGS.
18 and 21. In the assembled sachet/tube holder, each mounting boss
281a-c extends into a respective fluid passage 284a-c, each of
which is in fluid communication with a respective fluid chamber
285a-c (FIG. 21). The fluid passages 284a-c are sealed from one
another by webs 286. It is not necessary that the sachet is divided
into separate fluid chambers, and a single fluid chamber could be
provided. However, by providing independent fluid chambers, the
pump assembly and sachet/tube holder can be used to selectively
deliver different fluids from a single sachet.
[0141] In use, tubes are connected to the spigots and installed in
the tube holding portions 255a-c. More particularly, when the
hinged attachment member 265 is in the position shown in FIG. 15
(and connected to a sachet), a tube 287a-c is connected to each
spigot 283a-c. The tubes are preferably an interference fit on the
respective tube to assist in maintaining the connection between the
tubes and the spigots. The tubes 287a-c are held in a substantially
U-shaped configuration, and the hinged connecting member 265 is
moved to the position shown in FIG. 17. The tubes are moved so that
they extend around the respective tube holding portions 255a-c in a
similar manner as that described above with reference to FIGS. 9 to
13. The free ends of the tubes can then be pulled so that the tubes
are located under the lips 261 to assist in maintaining the tubes
in the tube holding portions 255a-c. The free ends of the tubes
287a-c extend through a channel 289 and out the side of the housing
253 as shown in FIGS. 18 and 19.
[0142] The installation of the tube holder 251 in the pump assembly
201 is shown in FIG. 20. In particular, the tube holder 251 and
sachet 271 are inverted from the orientation shown in FIGS. 17 to
19, and the tube holder body is inserted into the recess 203 in the
pump housing 202. One edge of the tube holder 251 is inserted
first, and the opposite edge is pushed downwardly to the recess.
When the tube holder is in position in the recess 203 of the pump
housing 202, the tapered rotors 3 are positioned in the recesses
257 of the tube holding portions 255a-c and engage the tubes 287a-c
so that actuation of the pump heads causes the tubes to be
occluded, and fluid delivered from the reservoirs through the
tubes. The tubes are preferably resiliently flexible so that they
return substantially to their original configuration after being
compressed by the rollers of the rotors during occlusion, meaning
that as they return to their original shape following occlusion.
They will suck fluid through the tubes behind the rollers, enabling
the flexible sachet to be used in anon-overhead configuration. For
example, the sachet could be positioned in use to be substantially
horizontal.
[0143] It is preferred that the pump heads could be operable in a
forward or rearward direction, to either dispense or suck
fluid.
[0144] A pair of biased clips 291 maintain the tube holder in
position in the pump housing by engaging a lip 299 of the tube
holder. To release the tube holder, the clips are moved in the
direction of arrow A in FIG. 20, and the tube holder can be lifted
out of the recess 203. Once empty, the sachet and tube holder can
be disposed of, and a further sachet and tube holder can be
connected to the pump housing in the manner described above.
[0145] FIGS. 22 and 23 show a coding system for coding the sachet
described above with reference to FIGS. 15 to 21. As shown in FIG.
22, the lip 299 of the tube holder 251 has a plurality of magnet
mounting sites 301a-301h for receipt of ferromagnetic inserts. In
the form shown, the magnet mounting sites are in the form of
apertures. The preferred embodiment is shown as having eight magnet
mounting sites, but more or less sites could be provided as
desired. By selectively placing magnets in one or more of the
sites, a binary code is provided which can be read by suitable
sensors to determine the contents of the sachet, in a manner to be
described below. In the embodiment shown, three magnets M.sub.1,
M.sub.2, M.sub.3 are located in the apertures 301a, 301c and
301e.
[0146] Referring now to FIG. 23, a corresponding number of sensors
3111a-311h are provided on or in the pump assembly main housing
202, in positions substantially corresponding to the positions of
the magnet mounting sites 301a-301h when the tube holder is
connected to the housing in the manner described above with
reference to FIG. 21. The magnet sensors can be provided either on
an upper surface of the housing or just below the surface, so that
each sensor can sense when a magnet is present in the corresponding
position on the tube holder. As will be readily apparent, the
magnets could be provided in other positions on the tube holder
than on the lip 299, and the magnet sensors could be positioned in
other corresponding positions on or in the pump assembly housing.
Further, the magnets could be provided on the sachet itself, rather
than the tube holder. The preferred type of magnet sensors are Hall
Effect sensors.
[0147] When the tube holder is inserted into the pump assembly main
housing and seated in its proper position, each sensor will sense
whether there is a magnet present at a respective magnet mounting
site on the tube holder. By using the sensors and magnets in the
configuration shown, the sensing can occur when the tube holder is
stationary relative to the pump assembly. For example, when the
tube holder of FIG. 23 is connected to the pump assembly main
housing, sensors 311a, 311c and 311e will sense that magnets are
present in locations 301a, 301c and 301e respectively, and the
remaining sensors will not detect any magnets. Sensors 301a, 301c
and 301e will then signal a microprocessor 321. The microprocessor
will determine from those signals the numbers and positions of the
magnets, and will then access a memory 323 to determine from the
code the substance(s) in the sachet (and, if more than one
substance is present, which pump to actuate to deliver that
substance). If the code is recognised, the processor activates
software routines associated with the code (and thereby the
particular sachet contents). The software routine may determine
when the pumps should be actuated, for how long, and in which
combination for example. Based on the software, the microprocessor
will signal a controller 325, which will selectively operate servo
motors 327, 329 and 331. If the code is not recognized, the pump
will not operate, and will issue a warning. Sachets containing
different substances will be coded with different combinations of
magnets, and the combinations will be stored in the memory 323
along with suitable software routines. That way, the pump assembly
will recognise the contents of a sachet and operate
accordingly.
[0148] It will be appreciated that the magnetic inserts provide a
number of magnetic areas for detection by the sensors on the pump
assembly. Other means of providing magnetic or magnetisable areas
could be used. For example, one or more strips of material could be
provided on the sachet, with discrete parts of the strip(s) being
magnetised as desired. Alternatively, a number of inserts of a
material which exhibits no magnetic properties until magnetised,
could be used. For example, Beryllium inserts could be used, some
or all of which are magnetised as required to provide the binary
code. As another example, the strip(s) of material could include a
number of linked Beryllium magnets, some or all of which are
magnetised as required.
[0149] When magnetic inserts are used, they would generally be
inserted to code the sachet when it is filled with one or more
substances by a supplier. Alternatively, the strip(s) of material
or the items of material which require magnetising could be
provided during manufacture of the sachet/tube holder, eg could be
moulded into the tube holder, and then magnetised as required when
the sachet is filled with one or more substances. Alternatively,
the sachet/tube holder could be pre-coded during manufacture for
use with a particular substance or substances.
[0150] The preferred tube holder and peristaltic pump head
described above have a number of advantages. In particular, the
tube holders in which the tubes exit and re-enter the tube race
maintain the tubes in a desired position in the race during a
pumping operation. Further, by virtue of the tube holder being
mounted to float transversely relative to the tapered rotor, the
rotor and tube race are self-aligning. By axially biasing the
rotor, the tube holder and the rotor as also self-adjusting to
maintain the desired pressure on a tube in the tube race.
[0151] The above describes preferred embodiments of the present
invention, and modifications may be made thereto without departing
from the scope of the invention.
[0152] For example, it is not essential that the rotor is axially
biased, nor that the tube holder is floating relative to the main
pump housing. However, including those features provides the
advantages outlined above.
[0153] In an alternative embodiment, rather than axially biasing
the rotor relative to the pump head housing, the tube holder could
be biased towards the rotor. Both the rotor and tube holder could
be axially biased towards one another.
* * * * *