U.S. patent application number 10/759503 was filed with the patent office on 2005-07-21 for method and apparatus for a molded tube and peristaltic pump.
Invention is credited to Romanyszyn, Michael T., Schroeder, Alfred A..
Application Number | 20050158196 10/759503 |
Document ID | / |
Family ID | 34749706 |
Filed Date | 2005-07-21 |
United States Patent
Application |
20050158196 |
Kind Code |
A1 |
Schroeder, Alfred A. ; et
al. |
July 21, 2005 |
Method and apparatus for a molded tube and peristaltic pump
Abstract
A peristaltic pump (10) and tube (18) system are provided. The
peristaltic pump (10) operates to squeeze the tube (18) and push
liquid in the tube (18) in the desired direction. The tube (18) is
molded, and thus allows for predictable and consistent flow
rates.
Inventors: |
Schroeder, Alfred A.; (San
Antonio, TX) ; Romanyszyn, Michael T.; (San Antonio,
TX) |
Correspondence
Address: |
Dennis Braswell
Braswell & Associates, P.C.
105 Soost Ct.
Mobile
AL
36608
US
|
Family ID: |
34749706 |
Appl. No.: |
10/759503 |
Filed: |
January 16, 2004 |
Current U.S.
Class: |
417/474 ;
417/572 |
Current CPC
Class: |
F04B 43/09 20130101 |
Class at
Publication: |
417/474 ;
417/572 |
International
Class: |
F04B 043/08; F04B
043/12 |
Claims
What is claimed is:
1. A pump for pumping a material, comprising: a motor; a molded
tube; and one or more compression heads coupled to the motor and
adapted to compress the molded tube for pushing the material in a
desired flow direction.
2. The pump of claim 1, wherein the molded tube comprises a first
section having a first inside diameter, and a second section having
a second inside diameter greater than the first inside
diameter.
3. The pump of claim 2, and further comprising a fitment coupled to
the second section.
4. The pump of claim 2, wherein the first section is a discharge
end of the molded tube.
5. The pump of claim 1, wherein the molded tube comprises an
injection molded tube.
6. A fluid delivery system, comprising: a peristaltic pump; a
molded tube coupled to the peristaltic pump through which the fluid
flows; a supply of the fluid coupled to the molded tube upstream of
the peristaltic pump; and a dispenser coupled to the molded tube
downstream of the peristaltic pump.
7. The system of claim 6, wherein the molded tube comprises a first
section having a first inside diameter, and a second section having
a second inside diameter greater than the first inside
diameter.
8. The system of claim 7, and further comprising a fitment coupled
to the second section.
9. The system of claim 7, wherein the first section is a discharge
end of the molded tube.
10. The system of claim 6, wherein the molded tube comprises an
injection molded tube.
11. The system of claim 6, wherein the fluid is a beverage
concentrate.
12. The system of claim 6, wherein the fluid is a
pharmaceutical.
13. A method of forming a molded tube for a peristaltic pump,
comprising: providing a core and a fitment; providing a cavity
adapted to mate with the core and fitment; injecting material into
the cavity for forming the molded tube around at least a part of
the core and fitment; and ejecting the molded tube and fitment from
the core.
14. The method of claim 13, wherein the injected material comprises
a thermosetting elastomer.
15. The method of claim 13, wherein ejecting comprises ejecting the
molded tube and fitment by supplying a gas through the core.
16. The method of claim 13, wherein providing a fitment comprises
forming the fitment and placing the fitment on the core.
17. The method of claim 13, wherein providing a fitment comprises
molding the fitment in place on the core.
18. The method of claim 13, and further comprising forming a
weakened area on the molded tube for removing an end of the
tube.
19. The method of claim 18, and further comprising forming a
removal tab proximate to the weakened area.
20. The method of claim 13, wherein the fitment has a fitment
inside diameter, and the fitment inside diameter is greater than or
equal to an inside diameter of a portion of the molded tube not
formed around the fitment.
21. The method of claim 13, wherein the molded tube has a discharge
end with an inside diameter different than a portion of the molded
tube not formed around the fitment.
Description
TECHNICAL FIELD OF THE INVENTION
[0001] This invention relates generally to pumping systems, and
more particularly to peristaltic pumping systems.
BACKGROUND OF THE INVENTION
[0002] Peristaltic pumps are widely used in various applications,
including applications in the beverage and pharmaceutical fields,
among other fields. Peristaltic pumps generally operate by
compressing a flexible tube or channel with one or more heads (or
other mechanisms). The head or heads pinch off a portion of the
tube or channel (against either a back or an opposing head) and
push fluid in the desired direction.
[0003] In some applications, a peristaltic pump itself is used over
and over again and the tube is frequently replaced, such as when a
beverage concentrate is depleted in a beverage system or a medicine
is depleted in a pharmaceutical application. In other applications,
one tube may be used with the same pump for a relatively long time.
In still other applications, the pump itself may be disposable
along with the tube.
[0004] Although peristaltic pumps offer certain advantages, they do
not economically allow for the kind of reproducible and precise
flow rates that are often required. In many instances, the
inaccuracies result from the tubes, which are made with an
extrusion process. The extrusion process results in variations in
the inside diameters of the tubes, as well as variations in the
thickness of the tube walls. Because of such variations, as tubes
are replaced, different flow rates result from the same pump. Also,
variations occur from pump to pump (and thus system to system),
because of the differences in the tubes, both in disposable tube
applications, and in applications where one tube is used for a
relatively long time. It is generally not practical to calibrate
systems to overcome the variations.
[0005] Thus, for example, where a beverage concentrate is to be
pumped at a specific flow rate for mixture with water at a given
ratio, tube variations result in inaccurate mixture ratios--and
hence different quality drinks--from tube to tube. Such beverage
systems are often used in restaurants and convenience stores (among
other locations), and the variations create unacceptable
differences in drink quality from batch to batch in the same
location, and from location to location. Similar issues are found
in other applications, such as those in the pharmaceutical
field.
[0006] Another problem with prior art peristaltic pumps is that the
pump inlet side of the tube is often attached to a tube fitment
that operates as a restriction to free flow to the inlet to the
pump.
[0007] Therefore, a need has arisen for peristaltic pump and tube
system that overcomes the limitations of prior art systems.
SUMMARY OF THE INVENTION
[0008] In accordance with the teachings of the present invention,
methods and apparatus for a molded tube and peristaltic pump are
provided which eliminate or substantially reduce the problems
associated with prior art systems.
[0009] In a particular embodiment, a pump for pumping a material is
provided which includes a motor, a molded tube, and one or more
compression heads coupled to the motor and adapted to compress the
molded tube for pushing the material in a desired flow direction.
In one embodiment, the molded tube comprises a first section having
a first inside diameter, and a second section having a second
inside diameter greater than the first inside diameter. In another
embodiment, a fitment is coupled to the second section. Also, the
discharge end of the tube may have an inside diameter greater or
less than other parts of the molded tube. The molded tube may be an
injection molded tube.
[0010] In another embodiment of the present invention, a fluid
delivery system is provided which includes a peristaltic pump, a
molded tube coupled to the peristaltic pump through which the fluid
flows, a supply of the fluid coupled to the molded tube upstream of
the peristaltic pump, and a dispenser coupled to the molded tube
downstream of the peristaltic pump. In one embodiment, the molded
tube comprises a first section having a first inside diameter, and
a second section having a second inside diameter greater than the
first inside diameter. In another embodiment, a fitment is coupled
to the second section. Also, the discharge end of the tube may have
an inside diameter greater or less than other parts of the molded
tube. The molded tube may be an injection molded tube.
[0011] Particular applications for the present invention include,
without limitation, beverage and pharmaceutical applications.
[0012] Also provided is a method of forming a molded tube for a
peristaltic pump, which includes providing a core and a fitment,
providing a cavity adapted to mate with the core and fitment,
injecting material into the cavity for forming the molded tube
around at least a part of the core and fitment, and ejecting the
molded tube and fitment from the core.
[0013] In a particular embodiment, the injected material is a
thermosetting elastomer. In one embodiment, the molded tube and
fitment are ejected by supplying a gas through the core. In another
embodiment, the fitment is formed and then placed on the core. In
an alternative embodiment, the fitment is molded in place on the
core. In another embodiment, a weakened area may be formed on the
molded tube for removing an end of the tube, and, if desired, a
removal tab may be formed proximate to the weakened area.
[0014] In another embodiment, the fitment has a fitment inside
diameter, and the fitment inside diameter is greater than or equal
to an inside diameter of a portion of the molded tube not formed
around the fitment. In still another embodiment, the molded tube
has a discharge end with an inside diameter different than a
portion of the molded tube not formed around the fitment.
[0015] One important technical advantage of the present invention
is that it includes a molded tube which allows more precise and
repeatable flow rates from peristaltic pumping systems than prior
art systems. Another important technical advantage of one
embodiment of the present invention is that it includes a molded
tube which may be formed in combination with a fitment. Still
another important technical advantage of the present invention is
that it includes a molded tube which may be formed with an
increased diameter portion which makes it easier to improve flow
rates into peristaltic pumping systems.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Reference is made in the description to the following
briefly described drawings, wherein like reference numerals refer
to corresponding elements:
[0017] FIG. 1 is a block diagram of one embodiment of a peristaltic
pump and tube according to the teachings of the present
invention;
[0018] FIG. 2 illustrates one embodiment of a tube for a
peristaltic pump according to the teachings of the present
invention;
[0019] FIG. 3 is an isometric view of one embodiment of a mold for
making a tube according to the teachings of the present
invention;
[0020] FIG. 4 illustrates another embodiment of a tube for a
peristaltic pump according to the teachings of the present
invention;
[0021] FIG. 5 is a cross sectional view of one embodiment of a
molding system for making a combined fitment and molded tube
according to the teachings of the present invention; and
[0022] FIG. 6 is a cross sectional view of the molding system of
FIG. 5 in the open position.
DETAILED DESCRIPTION OF THE INVENTION
[0023] As shown in FIG. 1, a peristaltic pump 10 is shown in block
form, which includes a motor 12, a shaft 14, and head (or heads)
16. Head or heads 16 engage a molded tube 18.
[0024] The head or heads 16 squeeze the tube 18 (against a back or
opposing head or heads) and push fluid in the desired direction. In
the particular example illustrated in FIG. 1, the fluid comes from
a supply 20, which may be a bag of fluid, such as a plastic bag
used in a bag-in-box beverage system, or a pharmaceutical bag, used
for pharmaceuticals or other fluids. The supply 20 generally
includes a supply fitment 22 that is coupled to a tube fitment 24
through any of several known approaches. The tube fitment 24 may be
coupled to the tube 18 through any of several known approaches, or
as described below as part of the molding process. Downstream of
the pump 10, the tube 18 is coupled to dispenser 26. Dispenser 26
may be, for example and without limitation, a beverage dispenser or
a needle for an injection into a patient, or any other dispensing
device, and may also be simply the open end of the tube 18. It
should also be understood that the tube 18 or tube fitment 24 may
be coupled directly to the supply 20 (or to the supply fitment 22)
and to the dispenser 26, or through any number of intermediate
coupling devices. Of course, the pump may be integrated with the
dispenser or the supply.
[0025] Although a peristaltic pump with a motor, shaft, and head is
illustrated, any peristaltic pump mechanism may be used, including,
without limitation, those that squeeze a tube and move fluid in the
tube with one or more roller heads, sliding heads, caterpillar
mechanisms, wave mechanisms, cams, disks, or other devices.
Examples of particular peristaltic pumps are described in U.S. Pat.
Nos. 5,413,252 and 5,558,507, which are herein incorporated by
reference in their entirety. The incorporation of these examples is
illustrative only, and not by way of limitation, and thus is not
meant to limit the scope of the invention or to exclude from
coverage any other type of peristaltic pump mechanism. For ease in
describing any of the various peristaltic pump mechanisms, the
squeezing mechanism may be referred to herein as a compression
head. Also, although the supply 20 is illustrated as a flexible
bag, any source may be used.
[0026] The tube 18 of the present invention is molded, and is not
extruded as are prior art tubes. In a particular embodiment, the
molding process is an injection molding process. Because the
molding process allows for very precise tolerances, the kinds of
variations found in prior art tubes are substantially or completely
eliminated with the molded tube of the present invention. It should
be understood that any other suitable molding process may also be
used, including, without limitation, compression molding.
[0027] FIG. 2 illustrates a particular tube 18, in combination with
a tube fitment 24, before being used in a dispensing system such as
that shown in FIG. 1. In the particular embodiment shown in FIG. 2,
the tube 18 includes an end 30 and an expanded diameter section 32.
The end 30 is a sealed (or otherwise closed) end of the tube 18,
and ensures that the tube 18 remains clean before use (at which
time the end 30 is removed). It should be understood that the end
does not have to be sealed.
[0028] The expanded diameter section 32, although not necessary in
all embodiments of the present invention, provides a significant
advantage over prior art tubes. In particular, by forming the
expanded diameter section 32 with an inside diameter greater than
that of the main portion of tube 18, the tube fitment 24 (or supply
fitment if the tube is coupled directly to the supply) may have an
inside diameter equal to or greater than that of the main portion
of tube 18, and can be easily coupled to the tube 18 (the tube may
also be formed on the fitment, as described below). With such a
fitment, flow to the pump inlet side of the tube is not restricted
(as the diameter is not diminished), and thus the peristaltic pump
is not "starved" and its performance limited thereby. In some prior
art systems, tube fitments cause inlet pump flow restrictions, as
it is difficult to stretch an extruded tube over a wide tube
fitment. The flow restriction issue is particularly important in
pumping relatively high viscosity liquids, such as, without
limitation, orange juice concentrate, wherein inlet flow
restrictions can significantly affect desired flow rates.
[0029] The expanded diameter section 32 may be formed in other
processes as well, such as, without limitation, with an expansion
mandrel inserted into the tube 18. Furthermore, the expanded
diameter section may be formed with features, such as, without
limitation, shoulders, grooves, or lips, to accommodate the tube
fitment 24 (or supply fitment) and enhance the fit between them.
However, it should be understood that any approach may be used to
couple the tube with a fitment.
[0030] FIG. 3 is an exploded view of one embodiment of a molding
system for forming a molded tube 18 according to the teachings of
the present invention. As shown in FIG. 3, a male plug (or core) 40
is formed on a base 42. A cavity block 44 having a cavity 46 mates
with the core 40. Injection material, such as, without limitation,
an injection-moldable grade of a thermosetting elastomer, for
example "liquid silicone" rubber, is injected into the cavity 46
and cured around the core 40 to form the molded tube 18 shown in
FIG. 3. It should be understood that other injection materials,
such as, without limitation, a thermoplastic elastomer, may also be
used.
[0031] The particular core shown in FIG. 3 includes a base 48 for
forming expanded diameter section 32. It should be understood,
however, that, although desirable, no such base or expanded
diameter section is required as part of the present invention. As
discussed above, it is also desirable that the top of the tube 18
be closed, and thus the tube 18 is shown with a sealed end 30
(which may or may not have the same diameter as that of the main
section of the tube). However, it should be understood that no such
sealing is required as part of the present invention. Also, it
should be understood that the end of the molded tube 18 opposite
the section 32 (the discharge end) may be molded to form any shape
desirable for coupling with downstream devices, and thus may have
an expanded or reduced diameter. In some applications, for example,
without limitation, those with high flow rates or relatively large
diameter tubes, dripping is reduced by forming the discharge end
with an inside diameter less than that of the main portion of tube
18.
[0032] As shown in FIG. 4, the tube 18 may be (but need not be)
formed with a weakened area 50 to facilitate easy removal of the
end 30. Also, a removal tab 52 may be formed proximate to the
weakened area 50 to allow a user to tear away the end 30 before use
of the tube.
[0033] The tube 18 may be ejected from the mold system by any
suitable approach. One approach, without limitation, is to inject a
gas through a gas port 54, which allows gas (such as, without
limitation, air) to flow through the end of the core 40 to eject
the molded tube 18.
[0034] FIGS. 5 and 6 are cross sectional views of another
embodiment of a system for molding a tube 18 according to the
teachings of present invention. In the particular embodiment shown
in FIGS. 5 and 6, the tube 18 is molded around a fitment 24. FIG. 5
shows the molding system in the closed position, and FIG. 6
illustrates it in the open position, with the tube 18 ready to be
ejected. The fitment 24 may be of any suitable material, including,
without limitation, plastic or metal. The fitment 24 may be formed
in another process and inserted into the mold before it is closed,
or molded in place in a shuttle mold system that allows for the
injection of the fitment material and for injection of the tube
material. If desired, although not required, the materials may be
chosen so that they chemically bond to one another. With the
embodiment of FIGS. 5 and 6, a combined tube and fitment are
produced, and no additional step of coupling a tube fitment with
the tube is necessary.
[0035] An air injection pin 56 is fully inserted during the
injection process, to prevent the injection material 58 from
entering an ejection channel 60. Ejection channel 60 runs from the
end of the core 40 to the gas port 54. When the air injection pin
56 is retracted, as shown in FIG. 6, the channel 60 is opened and
gas may be blown into the port 54 and through the core 40, to eject
the tube 18 from the mold. The mechanism shown form ejecting the
tube may also be used with the embodiment shown in FIG. 3.
[0036] The particular embodiments and descriptions provided herein
are illustrative examples only, and features and advantages of each
example may be interchanged with, or added to the features and
advantages in the other embodiments and examples herein. Moreover,
as examples, they are not meant to limit the scope of the present
invention to any particular described detail, and the scope of the
invention is meant to be broader than any example. For example, and
without limitation, although beverage and pharmaceutical
applications have been illustrated, the present invention may be
used with any other fluid delivery system. And, in general,
although the present invention has been described in detail, it
should be understood that various changes, alterations,
substitutions, additions and modifications can be made without
departing from the intended scope of the invention, as defined in
the following claims.
* * * * *