U.S. patent application number 13/901845 was filed with the patent office on 2014-06-12 for diaphragm pump.
The applicant listed for this patent is Richard Weatherley. Invention is credited to Richard Weatherley.
Application Number | 20140161644 13/901845 |
Document ID | / |
Family ID | 46546662 |
Filed Date | 2014-06-12 |
United States Patent
Application |
20140161644 |
Kind Code |
A1 |
Weatherley; Richard |
June 12, 2014 |
Diaphragm Pump
Abstract
A disposable pump has a pump unit 4 engaging with a drive unit
6. The drive unit drives a piston 18. The pump has an internal
chamber having a flexible wall which engages with the piston 18 to
allow a snap fit. The pump unit 4 is manufactured out of only three
mouldings, one being the flexible wall which forms in part the
membrane or diaphragm of the pump, sandwiched between upper and
lower units 50,70.
Inventors: |
Weatherley; Richard; (Kent,
GB) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Weatherley; Richard |
Kent |
|
GB |
|
|
Family ID: |
46546662 |
Appl. No.: |
13/901845 |
Filed: |
May 24, 2013 |
Current U.S.
Class: |
417/360 |
Current CPC
Class: |
F04B 43/04 20130101;
F04B 53/22 20130101; F04B 43/021 20130101 |
Class at
Publication: |
417/360 |
International
Class: |
F04B 53/22 20060101
F04B053/22; F04B 43/04 20060101 F04B043/04 |
Foreign Application Data
Date |
Code |
Application Number |
May 25, 2012 |
GB |
1209238.3 |
Claims
1. A disposable pump unit for engagement with a drive unit, the
drive unit including a piston driven by a drive unit, the
disposable pump unit comprising: an internal chamber having a
flexible wall, a pump inlet in communication with the internal
chamber through an inlet one-way valve; a pump outlet in
communication with the internal chamber through an outlet one-way
valve; wherein: the disposable pump unit further comprises detent
extensions for engaging in a snap fit with the drive unit to form a
snap fit unit; and further comprising a gripping part formed on the
flexible wall arranged to mate with the piston when the disposable
pump unit is engaged in a snap fit with the drive unit.
2. A disposable pump according to claim 1 wherein the disposable
pump unit comprises: a rigid housing made up of an outer unit and
an inner unit defining the internal chamber between the outer unit
and the inner unit; and a flexible diaphragm between the inner unit
and the outer unit, the flexible diaphragm defining the flexible
wall.
3. A disposable pump according to claim 2 wherein the detent
extensions are legs extending from the outer unit past the inner
unit for engagement with the drive unit.
4. A disposable pump according to claim 1 wherein the gripping part
is a separate rigid part mounted on the flexible wall.
5. A disposable pump unit according to claim 1 wherein the
disposable pump unit is formed of an outer unit, an inner unit and
a diaphragm unit between the outer unit and the inner unit, wherein
the internal chamber is defined in the outer unit and the flexible
wall and gripping part is an integral part of the diaphragm
unit.
6. A disposable pump unit according to claim 2, wherein the inlet
one-way valve comprises an inlet tongue integrally formed in the
diaphragm unit; and the outlet one-way valve comprises an outlet
tongue integrally formed in the diaphragm unit.
7. A disposable pump unit according to claim 2, wherein the outer
unit comprises an inlet channel between the internal chamber and
the inlet valve, the outlet channel communicating with an inlet
valve chamber in the outer unit facing an inlet channel in the
inner unit in communication with the pump inlet, the inlet tongue
in flexible engagement against the inlet channel to provide a
one-way valve action; and the outer unit comprises an outlet
channel between the internal chamber and the inlet valve, the
outlet channel communicating with an outlet channel end in the
outer unit facing an outlet valve chamber in the inner unit in
communication with the pump outlet, the outlet tongue in flexible
engagement against the end of the outlet channel to provide a
one-way valve action.
8. A disposable pump unit according to claim 2 wherein the detent
extensions are legs extending from the outer unit past the inner
unit for engagement with the drive unit.
9. A two-part pump comprising a disposable pump unit and a drive
unit comprises a piston; wherein the disposable pump unit
comprises: an internal chamber having a flexible wall, a pump inlet
in communication with the internal chamber through an inlet one-way
valve; a pump outlet in communication with the internal chamber
through an outlet one-way valve; detent extensions for engaging in
a snap fit with the drive unit to form a snap fit unit; and a
gripping parts integrally formed on the flexible wall arranged to
mate with the piston when the disposable pump unit is engaged in a
snap fit with the drive unit; and the drive unit further comprises
a motor for driving the piston in the drive unit in reciprocating
action.
10. A two-part pump pump according to claim 9 wherein the
disposable pump unit comprises: a rigid housing made up of an outer
unit and an inner unit defining the internal chamber between the
outer unit and the inner unit; and a flexible diaphragm between the
inner unit and the outer unit, the flexible diaphragm defining the
flexible wall.
11. A two-part pump pump according to claim 10 wherein the detent
extensions are legs extending from the outer unit past the inner
unit for engagement with the drive unit.
12. A two-part pump pump according to claim 9 wherein the gripping
part is a separate rigid part mounted on the flexible wall.
13. A two-part pump according to claim 9, wherein the drive unit
includes holes for engagement with the detent extensions of the
disposable pump unit.
14. A two-part pump according to claim 9 wherein the drive unit
includes a recess and the disposable pump unit includes a boss
having an opening, the boss being in engagement with the recess
when the detent extensions grip the disposable pump unit to locate
the disposable pump unit on the drive unit.
15. A two-part pump according to claim 9 wherein the piston passes
through the opening into a mounting chamber holding the gripping
unit when the detent extensions grip the disposable pump unit.
16. A two-part pump according to claim 9, wherein the gripping part
is in the form of a socket and the piston has an end shaped to
releasably mate with the socket.
17. A two-part pump according to claim 16 wherein the end of the
piston has a ball arranged to mate with a spherically socket as the
gripping part.
18. A two-part pump according to claim 9 wherein the one of the
gripping part and the end of the piston includes a magnet and the
other of the gripping part and the end of the piston includes a
magnetic material so that the gripping part and the end of the
piston form a magnetic coupling.
Description
FIELD OF INVENTION
[0001] The invention relates to a diaphragm pump, especially for
example to a diaphragm pump having a removable or disposable pump
unit cooperating with a drive unit.
BACKGROUND ART
[0002] A diaphragm pump is a type of pump in which a driven
diaphragm, sometimes known as a membrane, is moved to increase and
decrease the volume of a chamber. The chamber is connected to an
inlet one-way valve and an outlet one-way valve.
[0003] US 2009/0035152 describes a fluid pump with a disposable
element, the disposable element including the chamber. In one
embodiment, the disposable element includes a flexible membrane
that forms not just the membrane adjacent to the chamber but forms
the valves on the inlet and outlet. The valves are not automatic
one-way valves but are driven by solenoids to be open and
closed.
[0004] Where disposable pumps are used, the cost of the disposable
element is critical. There is therefore a need for a pump element
that is simple and easy to manufacture.
SUMMARY OF INVENTION
[0005] According to a first aspect of the invention, there is
provided a disposable pump unit with detent extensions for engaging
in a snap fit with a drive unit to form a snap fit unit and a
gripping part integrally formed on the flexible wall arranged to
mate with the piston (18) when the disposable pump unit is engaged
in a snap fit with the drive unit.
[0006] By arranging for a separate disposable unit which can simply
snap fit on a drive part embodiments of the invention can
automatically align and mate the piston with the gripping part
mounting of the disposable unit is made easy and quick.
[0007] In one arrangement, the disposable pump unit is formed of an
outer unit, an inner unit and a diaphragm unit between the outer
unit and the inner unit. The internal chamber may be defined in the
outer unit and the flexible wall and gripping part may be integral
parts of the diaphragm unit. By making the disposable pump unit out
of only three components manufacture is simplified.
[0008] Each of the inlet and outlet one-way valves may have a
tongue integrally formed in the diaphragm unit. This integrally
forms the moving part of the valves without requiring an additional
component.
[0009] The detent extensions may be legs extending from the outer
unit past the inner unit for engagement with the drive unit. Such
extended legs provide a convenient attachment mechanism.
[0010] In another aspect, the invention relates to a two-part pump
with a disposable pump unit and a drive unit with a motor for
driving the disposable pump unit.
[0011] The drive unit may include holes for engagement with the
detent extensions of the disposable pump unit.
[0012] In embodiments, the drive unit may include a recess and the
disposable pump unit may include a boss having an opening, the boss
being in engagement with the recess when the detent extensions grip
the disposable pump unit to locate the disposable pump unit on the
drive unit. In this position, the piston unit may pass through the
opening. The accuracy of mating can be addressed.
[0013] In a further aspect, the invention relates to a disposable
pump unit for engagement with a drive unit.
BRIEF DESCRIPTION OF DRAWINGS
[0014] For a better understanding of the invention, embodiments of
the invention will be described, purely by way of example, with
reference to the accompanying drawings, in which:
[0015] FIG. 1 shows a perspective view of a first embodiment of the
two part pump with the parts separated;
[0016] FIG. 2 shows an end view of the two part pump with the two
parts separated;
[0017] FIG. 3 shows a section with the two parts mated;
[0018] FIG. 4 shows a longitudinal section with the two parts
mated;
[0019] FIG. 5 shows one piece of the disposable pump unit of the
above embodiment;
[0020] FIG. 6 shows another piece of the disposable pump unit;
[0021] FIG. 7 shows the third piece of the disposable pump unit;
and
[0022] FIG. 8 shows a detail of an alternative embodiment.
[0023] The drawings are schematic and the exact sizes and shapes of
various components may vary. The description of the components is
not necessarily repeated for different figures.
DETAILED DESCRIPTION
[0024] Referring to FIGS. 1 and 2, a perspective view and an end
view respectively, a pump 2 is made up of a disposable pump unit 4
and a drive unit 6. The two parts are arranged to be able to be
fitted together in a push fit, as illustrated in FIG. 3 which is a
section through the pump 2 with the disposable pump unit 4 fitted
into drive unit 6. The drive unit 6 contains a motor 28 (FIG. 4)
which drives drive piston 18. The disposable pump unit includes a
pump chamber 22 (FIG. 3) which will be described later, as well as
pump inlet 24 and pump outlet 26 (FIGS. 1 and 2).
[0025] FIG. 4 shows the assembled pump 2 in longitudinal section
through pump inlet 24. In the drive unit 6 may be seen a drive
unit, here an electric motor 28 connected to drive shaft 30 which
drives the drive piston 18 through a cam 32.
[0026] In use, the motor is driven to rotate which rotates drive
shaft 30 and which causes reciprocating motion of the drive piston
18 by virtue of cam 32.
[0027] The disposable pump unit 4 is manufactured from only three
plastics mouldings, namely a outer unit 50, a inner unit 70, and a
diaphragm sheet 60 which is sandwiched between the outer unit 50
and inner unit 70 in the disposable pump unit. These units are
illustrated separately in FIGS. 5, 6 and 7 showing the outer unit
50, diaphragm sheet 60 and inner unit 70--respectively. Please note
that in order to show the internal workings FIGS. 6 and 7 show
inverted views compared to FIG. 5--the diaphragm sheet 60 and inner
unit 70 are inverted to make up the assembled pump 2. Thus, the
inlet is to the outer left in FIG. 5 but in FIGS. 6 and 7 it is the
outlet that is in outer left.
[0028] Legs 10 depend from the disposable pump unit 4 and have a
detent lug 12 on the ends. The legs 10 are flexible and are formed
in the outer unit 50 and extend part the inner unit 70 towards the
drive unit 6. Holes 16 are provided through fixing plate 14 on the
drive unit 6 for engagement with the legs 10. In use, when the
disposable pump unit 4 is fitted onto the drive unit 6, the detent
lug 12 passes through the hole 16 in the fixing plate 14 and the
detent lug 12 engages with the fixing plate 14. This forms a secure
fit. To remove the disposable pump unit 4, the user compresses the
legs 10 to disengage the detent lug 12 from plate 14 and removes
the disposable pump unit 4.
[0029] The drive unit 6 also contains a drive piston 18 which
engages with a gripping part 20 in the disposable pump unit as will
be described later.
[0030] Referring to FIG. 6, the disposable pump unit forms a
diaphragm pump, also referred to as a membrane pump. The diaphragm
sheet 60 forms the diaphragm 62 of the pump as well as inlet tongue
64 and outlet tongue 66 which form the moving parts of inlet valve
34 and outlet valve 36. Note that the gripping part 20 is
integrally formed with diaphragm 62 and contains a recess in its
centre for gripping the drive piston. The disposable pump unit 60
is formed of a sheet of flexible plastics.
[0031] Referring to FIGS. 5 and 7, the inlet and outlet valves 34,
36 are formed by inlet valve chamber 52 and outlet valve chamber
72. Note that the outlet valve chamber 72 is formed in inner unit
70 and the inlet valve chamber 52 in the outer unit 50. The inlet
valve chamber 52 is in communication with inlet channel 54 which
communicates between the inlet valve chamber 52 and the pump
chamber 22. The outlet valve chamber 72 is in communication with
outlet channel 56. Note that both the inlet and outlet channels 54,
56 are formed in outer unit 50--the shape of the outlet valve
chamber 72 is arranged to have an extended recess 74 which faces
the end 58 of the outlet channel 56.
[0032] The outer unit 50 and inner unit 70 are made of
less-flexible resilient plastics so as to retain their shape when
mated with the inner unit.
[0033] The pump inlet 24 is connected to inlet opening 78 in the
inner unit 70 which faces the inlet valve chamber 52 and inlet
tongue 64.
[0034] The outlet valve 36 operates as follows. Fluid in the pump
can flow outwards along outlet channel 54 to end 58 where it forces
the outlet tongue 66 to bend away from the end 58 of the outlet
channel 56 into extended recess 74 to open the outlet valve 36. The
fluid can then pass to pump outlet 26. This allows fluid to exit
the pump chamber 22. However, fluid cannot return since in the
event of flow in the other direction the outlet tongue 66 is urged
against the end 58 of the outlet channel to seal the outlet channel
56.
[0035] The inlet valve 34 operates in a similar way but in the
reverse direction. Fluid flows in from inlet 24 through inlet
opening 78. The inlet tongue 64 is urged away from the inlet
opening into inlet valve chamber 52 and from there the fluid flows
along inlet channel 54 into chamber 22. In reverse, however, fluid
cannot flow out along inlet channel 54 since the fluid urges the
inlet tongue 64 against inlet opening 78.
[0036] Thus, in use, the motor 28 causes reciprocating motion of
piston 18 which urges the diaphragm 62 to reduce the size of the
chamber and then increase it. As the chamber size increases, fluid
is drawn in through the pump inlet 24 and inlet valve 34 and then
as the chamber size decreased the fluid is expelled through outlet
valve 36 and pump outlet 36.
[0037] Some further design features improve operation of the unit
and render it easier to manufacture.
[0038] The shape of the end of the piston unit 18 contains a
chamfered edge lip 38 around its circumference. This makes it easy
for the gripping part 20 to be mated with the end of the piston
unit.
[0039] The formation of the disposable pump unit 4 using only three
pieces, each of which can be separately moulded, allows for the
disposable pump unit to be manufactured relatively cheaply.
[0040] Moreover, the location of the channels and their design has
been designed to allow the pieces to be moulded as simply as
possible. Only the pump inlet 24 and pump outlet 26 require
internal channels, i.e. channels not open at outer or bottom--the
rest of the unit simply is a single shape with recesses. This
minimises the need for side arms in the injection moulding
apparatus which greatly increases the density of mouldings that can
be moulded in a single moulding operation.
[0041] Further aspects of the design allow the two parts to be
joined together with minimal rattles in the assembled pump. In
particular, a recess 80 surrounds the piston unit 18 at the outer
of the drive unit 6 and a boss 82 is provided on the underside of
the inner unit 70 to engage with this recess. The boss 82 is on rim
84 which defines an internal mounting chamber 86 which holds the
gripping part 20. The boss 82 accordingly has opening 88 through
which the piston unit 18 can pass to reach the gripping part 20.
The recess 80 is slightly less deep than the height of the boss 82,
for example 0.1 mm to 1 mm. This means that the boss 82 is urged
slightly inwards when the two parts are mated, since the plastics
used in the inner unit are slightly flexible as well as resilient
which allows rim 84 to bend slightly. This resilience urges the
boss 82 and recess 80 together which reduces rattling when the pump
is operated in use.
[0042] Further, the design allows the piston unit 18 to
automatically engage the gripping part 20 when the legs 10 are
passed through holes 16 in the plate 14 without requiring
additional alignment. Full mating of piston unit 18 and gripping
part 20 may occur after the motor has been switched on to fully
insert piston unit 18 inside gripping part 20.
[0043] Thus, the complete design uses only three plastics mouldings
for the disposable pump unit and yet fully implements the chamber
22, and the inlet and outlet valves 34, 36 of a diaphragm pump. The
disposable pump unit of the pump is therefore relatively
inexpensive.
[0044] The pump is suitable for any application where a disposable
pump may be used. In particular, the pump may be used for medical
applications.
[0045] Referring to FIG. 8, an alternative embodiment of the pump
unit has a different snap fit connector. In this case, the end of
the piston unit 18 is a ball 90 which is gripped by the gripping
part, in this case moulded spherical socket 92.
[0046] In an alternative embodiment, not shown, a steel shim disc
is bonded to the bottom of the pump diaphragm as the gripping part,
and a magnet provided on the end of piston unit 18 for magnetic
coupling to the gripping part.
[0047] Those skilled in the art will realise that the exact design
as described above may be varied as required. For example, the pump
inlet 24 and pump outlet 26 are both provided on the inner part 70
of the disposable pump unit 4, which requires the inlet and outlet
valves 34,36 to operate in different directions. Alternative
embodiments can provide one of the pump inlet 24 and pump outlet 26
on the outer part 50 and the other on the bottom part 70, or indeed
both on the outer part 50, with different arrangements of channels
and valves.
* * * * *