U.S. patent application number 10/697529 was filed with the patent office on 2004-06-10 for diaphragm pump.
This patent application is currently assigned to Bayer Aktiengesellschaft. Invention is credited to Jahn, Peter, Krumbach, Bernhard.
Application Number | 20040109769 10/697529 |
Document ID | / |
Family ID | 32474847 |
Filed Date | 2004-06-10 |
United States Patent
Application |
20040109769 |
Kind Code |
A1 |
Jahn, Peter ; et
al. |
June 10, 2004 |
Diaphragm pump
Abstract
Diaphragm pump with a multipart pump body, comprising at least
three rigid plates and at least two elastic diaphragms arranged
between said plates , the plates forming at least one pumping
chamber and at least two shut-off chambers, and the pumping chamber
and shut-off chambers forming, together with an inlet duct
connecting ducts and an outlet duct, a passage duct; the pumping
chamber and the shut-off chambers being separated by the diaphragms
in each case into a product space and a control space with an
axially movable disc, with an extended rod attached on one side,
inserted into said control space, so that the rod, attached on one
side of the movable disc, projects outside the metering head and
can be adjusted outside the pump to move the movable disc axially
and reduce or increase the maximum possible diaphragm travel in the
pumping chamber.
Inventors: |
Jahn, Peter; (Leverkusen,
DE) ; Krumbach, Bernhard; (Leverkusen, DE) |
Correspondence
Address: |
Norris, McLaughlin & Marcus P.A.
30th Floor
220 East 42nd Street
New York
NY
10017
US
|
Assignee: |
Bayer Aktiengesellschaft
Leverkusen
DE
|
Family ID: |
32474847 |
Appl. No.: |
10/697529 |
Filed: |
October 30, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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10697529 |
Oct 30, 2003 |
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10600299 |
Jun 20, 2003 |
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10600299 |
Jun 20, 2003 |
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10383954 |
Mar 7, 2003 |
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Current U.S.
Class: |
417/395 |
Current CPC
Class: |
F04B 43/0733
20130101 |
Class at
Publication: |
417/395 |
International
Class: |
F04B 043/06 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 12, 2002 |
DE |
102 16 146.1 |
Claims
We claim:
1. Multipart pump head, comprising at least three rigid plates,
said at least three rigid plates comprising two outer plates (201,
205) and one inner plate (203), and at least two elastic diaphragms
(204, 202) arranged between these plates (201, 203, 205), the
plates (201, 203, 205) forming at least one pumping chamber (211)
and at least two shut-off chambers (210, 212), in the geometry of a
spherical segment, a spherical zone, a cylinder or a truncated
cone, each with an inlet orifice (240) and an outlet orifice (241)
for feed material, and the pumping chamber (211) and the shut-off
chambers (210, 212) forming, together with an inlet duct (207),
connecting ducts (208) and (209) and an outlet duct (206), a
passage duct, the pumping chamber (211) and the shut-off chambers
(210, 212) being separated by the diaphragms (204, 202) in each
case into a product space (230, 231, 232) and a control space (220,
221, 222), and the control spaces (220, 221, 222) having control
lines (119, 120, 121) which are connected to a control unit (100,
115), wherein the control space of at least one pumping chamber is
enlarged sufficiently to accommodate an axially movable disc (1001)
with an extended rod (1002) attached on one side, which is inserted
into said control space, with the rod attached on one side of the
movable disc extending through the outer plate and projecting
outside the head and is adjustable (1003) outside the pump, whereby
the disc (1001) located in the control space is movable axially to
reduce or increase the maximum diaphragm travel in the pumping
chamber, so that the liquid volume conveyed per conveying stroke
can be varied and the pump is operable in a part-stroke operating
mode, without the dead-space volume in the product space being
increased.
2. Diaphragm pump with a multipart pump head according to claim 1,
wherein said diaphragm pump has a decentral electropneumatic
control unit.
3. Diaphragm pump according to claim 2, wherein the pump has a
product space (231) defined, in part, by a surface having a vertex
and a groove (213) which runs from the vertex of the product space
to the outlet orifice.
4. Diaphragm pump according to claim 2, wherein the pumping chamber
(211) and the shut-off chambers (210, 212) are sealed by means of
the diaphragms (204, 202).
5. Diaphragm pump according to claim 2, wherein the diaphragms
(204, 202) are of an elastic material.
6. Diaphragm pump according to claim 2, wherein the pump is
comprised of at least three plates (201, 203, 205), and the pumping
chamber (211) and the shut-off chambers (210, 212) are formed by
depressions (210', 211', 212') in the plates (201, 203, 205).
7. Diaphragm pump according to claim 2, wherein the movable disc
(1001) on the side facing the diaphragm is planar or has an obtuse
cone or is adapted to the shape of the product-side pumping chamber
and is provided with a plurality of bores (1007).
8. Diaphragm pump according to claim 2, wherein the diaphragm (204)
of the pumping chamber is a chambered diaphragm.
9. Diaphragm pump according to claim 2, wherein it is a double
diaphragm pump which consists of three plates and in which all the
pumping and shut-off chambers are formed in the middle plate.
10. Diaphragm according to claim 2, wherein in the middle plate
four shut-off chambers (1200, 1201, 1202, 1203) are associated with
said at least one pumping chamber (1205).
11. Diaphragm pump according to claim 2, consisting of three plates
and operable as a multi-way distributor valve.
12. A multi-way distributor valve, characterized in that the latter
comprised of the diaphragm pump of claim 11 having a central
material inlet duct (1308'), a distributor chamber (1310') and a
multiplicity of connecting ducts (1312') having associated shut-off
chambers (1314') and following outlet ducts (1316').
13. Multiduct diaphragm valve comprised of the multipart pump head
of claim 1, having three plates, wherein a distributor chamber is
connected by means of an inlet duct via a connecting duct to at
least one shut-off chamber which has an outlet duct, and the
chambers have depressions of identical size and can be activated
separately, so that, for the passage of a material, at least two
chambers must be opened simultaneously in the desired throughflow
direction, and all the chambers are actuated by a decentral control
unit.
14. Diaphragm pump according to claim 2, wherein at least one outer
plate is thermally controllable.
15. Diaphragm pump according to claim 2 further comprising
controllable valves along with a decentral control unit, wherein,
in the throughflow direction through the pump, the inlet duct with
a throughflow shut-off chamber and a connecting duct to the pumping
chamber has a larger hydraulic cross section than the discharging
connecting duct with a following shut-off chamber and outlet
duct.
16. Diaphragm pump according to claim 2 with controllable valves
and with a decentral control unit, wherein the volume of the
pumping chamber is in the range of 0.005 ml to 1000 ml.
17. Diaphragm pump according to claim 2, with controllable valves
along with a decentral control unit, wherein the product-side
dead-space volume of the pumping chamber is 0.1% to 20% of the
pumping chamber volume.
18. Diaphragm pump according to claim 2, wherein the product spaces
of the shut-off chambers (210, 212) are designed smaller than the
product space of the pumping chamber (211).
19. Diaphragm pump according to claim 2, wherein at least one
pumping chamber is provided in the middle plate, and at least three
smaller shut-off chambers are associated with each pumping chamber
and each shut-off chamber has a connecting duct to the pumping
chamber and an inlet duct or outlet duct for the supply or
discharge of at least one fluid, and all the chambers are
separately activatable via a decentral control unit.
20. Diaphragm pump according to claim 2, wherein a plurality of
inlet or outlet ducts with shut-off chambers are associated with a
pumping chamber and a mixing chamber is provided in at least one
outlet duct, said mixing chamber being associated with a second
pumping chamber with a plurality of inlet and outlet ducts and
shut-off chambers, adapted to pump around a sample intercepted in
the mixing chamber, so that, when a separate diluting agent is
supplied into the mixing chamber, the sample located there can be
diluted or mixed, in order, after mixing, to extract the diluted
sample by pumping it away and to analyze it.
21. A sampling system or conveying device comprising the diaphragm
pump of claim 2.
22. A method for conveying liquids with a viscosity range of 0.001
Pas to 10 Pas, which comprises conveying said liquids with a
diaphragm pump of claim 1.
23. A decanting appliance or decanting system comprising the
diaphragm pump of claim 1.
24. Diaphragm pump according to claim 5, wherein said elastic
material is an elastomer, silicone, fluoroelastomer,
polytetrafluoroethylene or a rubber.
25. Diaphragm pump according to claim 5, wherein said elastic
material is comprised of at least two interconnected material
layers having different moduli of elasticity.
26. Diaphragm pump according to claim 1, wherein the travel of one
or more of the diaphragms which separate the product space (231)
and control space (221) of the pumping chamber (211) or the product
spaces (230, 232) and control spaces (220, 222) of the shut-off
chambers (210, 212) is limited to produce a maximum deformation of
said one or more diaphragms into said product space of 20%.
27. Diaphragm pump according to claim 26, wherein said maximum
deformation is 10%.
28. Diaphragm pump according to claim 27, wherein said maximum
deformation is less than 5%.
29. Diaphragm pump according to claim 26, wherein said travel is
limited by dimensions of one or more of the shut-off chambers,
pumping chamber, control spaces and product spaces
Description
[0001] This application is a continuation-in-part of application
Ser. No. 10/600,299 filed Jun. 20, 2003, now pending, which is a
continuation-in-part of application Ser. No. 10/383,954, filed Mar.
7, 2003, now pending.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to a diaphragm pump as
disclosed in copending application Ser. No. 10/383,954, but with a
variable stroke volume, this being achieved by means of a metering
device in the form of a metering head, and to the use of this
diaphragm pump as a controllable valve or as controllable multi-way
distributor valves or multi-component distributor valves.
[0003] Copending application Ser. No. 10/383,954, the disclosure of
which is incorporated herein by reference, discloses a diaphragm
pump with a multipart pump body, said pump comprising at least of
three rigid plates and at least two elastic diaphragms arranged
between these plates, the plates forming, in particular, one
pumping chamber and at least two shut-off chambers, each with an
inlet and an outlet orifice for the feed material, and the pumping
chambers and shut-off chambers forming, together with an inlet
duct, connecting ducts and an outlet duct, a passage duct, the
pumping chamber and the shut-off chambers being divided by the
diaphragms in each case into a product space and a control space,
and the control spaces having control lines which are connected to
a control unit.
[0004] It was shown, when the diaphragm pump according to copending
application Ser. No. 10/383,954 was used, that this does not always
satisfy all requirements, particularly when substances of different
density are to be metered accurately or the diaphragm pump is to be
used as a multi-way valve.
[0005] The object of the present invention is, therefore, to
provide a diaphragm pump which is an improvement over the diaphragm
pump of application Ser. No. 10/383,954 and which, highly
miniaturized, conveys small volume quantities per unit of time and
possesses high short-term metering accuracy. The improved pump has
a good intake behavior and conveys against pressure, so that even
in the non-flooded state of the pump head, conveyance against
pressure and a part-stroke operating mode are possible, but a
sampling of the feed material is also possible at any time.
SUMMARY OF THE INVENTION
[0006] This object is achieved by an electropneumatically driven
pump head as illustrated in FIG. 2 which is constructed in a
modular lamella-like manner and which, multi-part, is comprised of
at least three rigid plates (lamellae), said at least three rigid
plates comprising two outer plates (201, 205) and one inner plate
(203) and at least two elastic diaphragms (204, 202) arranged
between these plates, the inner plate (203) and at least one outer
plate (205) forming at least one pumping chamber (211) and the
inner plate and the other of said at least two outer plates (201)
forming at least two shut-off chambers (210, 212), particularly in
the geometry of a spherical segment, a spherical zone, a cylinder
or a truncated cone, each with an inlet orifice (240) and an outlet
orifice (241) for the feed material, and the pumping chamber (211)
and the shut-off chambers (210, 212) forming, together with an
inlet duct (207), the connecting ducts (208) and (209) and an
outlet duct (206), a passage duct, the pumping chamber (211) and
the shut-off chambers (210, 212) being separated by the diaphragms
(204, 202) in each case into a product space (230, 231, 232) and a
control space (220, 221, 222), and the control spaces (220, 221,
222) having control lines (119, 120, 121) which are connected to a
control unit (100, 115), and wherein the control space of the
pumping chamber is enlarged sufficiently to accommodate an axially
movable disc (1001), having an extended rod (1002) attached on one
side, inserted into said control space, so that the rod attached on
one side of the movable disc is extended through the outside plate
and projects outside the metering head, and can be adjusted (1003)
from outside the pump, and, as a result, the disc (1001) located in
the control space is movable axially to reduce or increase the
range of possible diaphragm travel in the pumping chamber, so that
the metered liquid volume per conveying stroke can be varied and
the pump operated in a part-stroke operating mode, without the
dead-space volume in the product space being increased.
[0007] Preferably, the outer plate forming the pumping
chamber/control space within which the axially movable disc (1001)
is inserted is of stronger or thicker design than the other plates,
so as to accommodate said axially movable disc.
[0008] The invention relates, furthermore, to a diaphragm pump as
illustrated in FIG. 1, with a multi-part pump head which is
comprised of at least three rigid plates (lamellae), said at least
three rigid plates comprising two outside plates (201, 205) and an
inner plate (203) and at least two elastic diaphragms (204, 202)
arranged between these plates (201, 203, 205), the inner plate
(203) and one of said outside plates ( 205) forming at least one
pumping chamber (211) and said inner plate and the other outside
plate (201) forming at least two shut-off chambers (210, 212),
particularly in the geometry of a spherical segment, a spherical
zone, a cylinder or a truncated cone, each with an inlet orifice
(240) and an outlet orifice (241) for the feed material, and the
pumping chamber (211) and the shut-off chambers (210, 212) forming,
together with an inlet duct (207), the connecting ducts (208) and
(209) and an outlet duct (206), a passage duct; the pumping chamber
(211) and the shut-off chambers (210, 212) being separated by the
diaphragms (204, 202) in each case into a product space (230, 231,
232) and a control space (220, 221, 222), and the control spaces
(220, 221, 222) having control lines (119, 120, 121) which are
connected to a control unit (100, 115), the control space of the
pumping chamber being sufficiently enlarged to accommodate an
axially movable disc (1001), having a rod (1002) attached on one
side, inserted in the control space, so that the rod attached on
one side of the movable disc extends through the outer plate (205)
and projects outside the metering head and can be adjusted (1003)
from outside the pump, and, as a result, the disc (1001) located in
the control space can be moved axially to reduce or increase the
possible diaphragm travel in the pumping chamber, so that the
metered liquid volume per conveying stroke can be varied and the
pump operated in a part-stroke operating mode, without the
dead-space volume in the product space being increased, and wherein
said diaphragm pump has a decentral electropneumatic control unit
for driving the pump head. Preferably, the outer plate (205)
forming the pumping chamber/control space within which the axially
movable disc (1001) is inserted is of stronger or thicker design
than the other plates, so as to accommodate the movable disc
(1001).
DETAILED DESCRIPTION
[0009] The diaphragm pump according to the invention, comprised of
the pump head according to the invention and a decentral control
unit, makes it possible to convey small volume quantities per unit
of time, has high short-term metering accuracy, exhibits a good
intake behavior, is capable of conveying against pressure even in a
non-flooded state of the pump head and also is capable of
part-stroke operating mode at any time. The diaphragm pump
according to the invention makes it possible, in the most diverse
possible applications, to convey liquids with a viscosity range of
0.001 Pas to 10 Pas, preferably 0.001 to 5 Pas and, particularly
preferably, liquids with a viscosity of 0.001 to 2 Pas.
[0010] The disc (1001) movable in the axial direction in the
control space of the pumping chamber (211) by rotation of the
threaded rod makes it possible to reduce or increase the maximum
stroke travel of the conveying pump diaphragm (204), so that
pumping in a part-stroke operating mode is possible. In addition, a
reduction in the diaphragm load occurs, so that, depending on the
elastic material used, the permanent deformation arising is
compensated by a variation in the diaphragm stroke travel.
[0011] The axially movable disc (1001) within the control space of
the pumping chamber varies the possible diaphragm movement in the
axial direction in the range of from 1% to 100% of the structurally
largest stroke travel, the limitation preferably being from 10% to
100% and, particularly preferably, the limitation being in a range
of 20% to 100% stroke travel, without the dead-space volume of the
pumping chamber being increased.
[0012] The rod (1002) allows the adjustment of the movable disc
(1001) from outside of the diaphragm pump. The adjustment can be
for example motoric, hydraulic, pneumatic, a piezo-operated
adjustment or a simple manual adjustment. Anyway the adjustment is
done by rotary motion. The rod (1002) may be a threaded rod or
non-threaded rod.
[0013] In a preferred embodiment of the invention, the axial disc
adjustment within the control space of the pumping chamber may take
place at the adjusting wheel (1003), even automatically or by
remote control when an electrically operated motor or a hydraulic
or pneumatic drive is mounted.
[0014] An automatically adjustable part-stroke of the pump
diaphragm forms an actuator, so that, in combination with a
throughflow sensor, throughflow regulation can be set up.
[0015] The set delivery rate of the pump may be checked, for
example, by means of a balance. If deviations from the
predetermined metering rate occur, the balance transmits a signal
to the monitoring controller, and the controller transmits a
control signal to the drive which can move, in the axial direction,
the disc (1001) fastened to the output shaft in the pump control
space and thus adjust the pump-stroke volume, in order to make a
correction of the pump delivery rate.
[0016] The axially movable disc (1001) inserted in the control
space may have different shapes on the side facing towards the
diaphragm . The disc may be in the shape of a planar cylindrical
disc (FIG. 2a), of an obtuse cone (FIG. 2b) or of a spherical
segment as shown in FIG. 2 (1001). In particular, a shape adapted
to the product-side depression of the pumping chamber has
advantages to the effect that, in the case of a maximum adjustment
of the movable disc, the supplying and discharging connecting ducts
(208,209) of the pumping chamber are closed.
[0017] The axially movable disc (1001) is provided with orifices or
bores (1007) and, if appropriate, is additionally provided, on the
side facing away from the diaphragm, with a concentrically raised
ring (1008), so that the pneumatic connection cannot be closed in
the case of a complete return of the disc.
[0018] As compared with the diaphragm pump according to copending
application Ser. No. 10/383,954, the diaphragm pump improved
according to the present invention has a simpler setting or
variation of the metering capacity and of the volume flows to be
conveyed. The use of the part-stroke operating mode applies to
pumping chambers with a stroke volume of from greater than 10
.mu.l/stroke up to 100,000 .mu.l/stroke. In light of different
corrosion requirements in the chemical industry, the diaphragm pump
according to the invention can be produced cost-effectively from
various corrosion resistant materials. Repair and maintenance are
simple and inexpensive.
[0019] The design of the control or drive technology of the
diaphragm pump according to the invention has no influence on the
pump-head size and the possibility of integration in a miniaturized
test installation set-up. The diaphragm pump according to the
invention can be constructed in a modular manner, so that, by
appropriate additions or the exchange of module parts, an easy
adaptation of its functions to the feed material can be carried
out. The change in the metering capacity takes place, without the
displacement travel of the diaphragm or of the movable disc (1001)
in the pump head increasing the dead volume, so that the liquid
volume taken-in is displaced out of the pump head completely at any
time.
[0020] In a further preferred embodiment of the diaphragm pump or
of the pump head, by means of a pressure regulator preceding the
control unit, the control pressure on the diaphragm in all the
control spaces is at least 0.1 bar higher than the prevailing
pressure at the outlet duct of the pump head, preferably the
control pressure is at least 0.5 bar higher and, particularly
preferably, the control pressure is 1 bar higher than the pressure
to be expected at the outlet duct.
[0021] The higher differential pressure between the outlet duct
(206) and the control-side pressure ensures the leak-tight closing
of the respective inlet orifices in the chambers by means of the
diaphragm.
[0022] The diaphragms (202, 204) are preferably formed of an
elastic material, in particular of an elastomer, silicone,
Viton.RTM. fluroroelastomer, Teflon.RTM. polytetrafluoroethylene or
a rubber.
[0023] Preferred diaphragms are comprised of an elastic laminate of
at least two interconnected material layers with different modului
of elasticity. The individual layers are adhesively bonded or
connected to one another. In principle, this feature may also be
applied to the diaphragm pump of copending application Ser. No.
10/383,954.
[0024] Thus, for example, a thin Teflon.RTM. film may be connected
to a highly elastic rubber, in order to increase the required
return forces of the diaphragm laminate and thus reshape into the
original state, with insignificant auxiliary energy, a diaphragm
laminate which is deformed during the displacement of liquid.
[0025] A preferred version of the diaphragms used is one wherein
thin elastic films are partially chambered and the structural parts
or the components for diaphragm chambering are comprised of
corrosion-resistant materials and chamber up to 30% of the
product-touched diaphragm surface, preferably chamber up to 65% and
particularly preferably up to 80% of the product-touched diaphragm
surface.
[0026] The use of a chambered diaphragm reduces the plastic
deformation occurring under load, so that, under high mechanical
load, the plastic or permanent diaphragm deformation is extremely
low or has a negligible influence on metering accuracy. The two
plate-shaped diaphragm chamber elements in FIG. 3 (1100, 1101) are
preferably disc-shaped and on the outer diameter have a concentric
raised ring (1102, 1103) formed towards the diaphragm side, so that
large diaphragm-surface fractions are clamped and are not subject
to any deformation force or stretching force in the chambered
region.
[0027] Preferably, chamber elements are used in the case of a
diaphragm diameter larger than 10 mm to smaller than 1000 mm,
preferably in a diameter range of larger than 20 mm to smaller than
800 mm and, particularly preferably, in a diameter range of larger
than 25 mm to smaller than 200 mm.
[0028] A preferred version of the diaphragm pump or of the pump
head, characterized in that the pumping chamber and the shut-off
chambers are provided with associated chambered diaphragms, is
particularly advantageous.
[0029] A preferred version of the diaphragm pump or of the pump
head, characterized in that only the pumping chamber is provided
with a chambered diaphragm, is particularly advantageous (FIG.
3).
[0030] If large surface fractions of the diaphragm are chambered,
the product-side surface (1104) of the diaphragm chamber component
may be coated with an elastic layer or film in order to close
supplying and/or discharging connecting ducts of the pumping
chamber in a leak-tight manner (see FIG. 3).
[0031] A preferred version of the diaphragm pump or of the pump
head, in which a plurality of shut-off chambers have a common
diaphragm, is particularly advantageous (FIG. 1).
[0032] A preferred version of the diaphragm pump or of the pump
head is characterized in that the pump head is comprised of at
least three plates and the pumping and shut-off chambers are formed
by depressions in the plates (FIG. 2).
[0033] In a particularly preferred form of construction, the
diaphragm pump or the pump head is comprised of at least three
plates and the pumping and shut-off chambers (210, 211, 212) are
formed by depressions in the middle plate.
[0034] Another particularly preferred form of the diaphragm pump or
of the pump head is characterized in that it is comprised of at
least three plates and the pumping and shut-off chambers are formed
by depressions (210, 211, 212) in the outer plates.
[0035] In a particularly preferred embodiment of the diaphragm pump
or of the pump head, a groove (213), which connects the vertex of
the pumping-chamber depression to the outlet orifice of the pumping
chamber, is located at least in the product space of the pumping
chamber (231).
[0036] In a preferred embodiment, those walls of the control spaces
which are located opposite the diaphragm, but at least in the
pumping chamber, have a compensating volume in the form of a
sheet-like depression. As a result, when a vacuum prevails in the
control space, the diaphragm becomes deformed and can in extreme
situations fit snugly together with the adjustable disc which is
the wall of the control space. At the same time, an enlargement of
the respective product space takes place (illustrated by way of
example in FIG. 1 in the product space of the shut-off chamber
(212)).
[0037] In a particularly preferred embodiment of the diaphragm pump
or of the pump head, the compensating volume is at most 100% of the
respective associated product-space volume, preferably the
compensating volume is at most 20%, and, particularly preferably,
the compensating volume is at most 10% of the product-space
volume.
[0038] The compensating volume describes the space into which the
diaphragm present is deformed when a vacuum prevails. If the
compensating volume is increased and equipped with an adjustable
disc (1001), the compensating volume has no influence on the
product-side depression volume of the pumping chamber due to the
axial adjustment of the movable disc (1001).
[0039] Typically, the product spaces of the shut-off chambers (210,
212) are designed to be smaller than the product space of the
pumping chamber (211).
[0040] In a particularly preferred embodiment of the diaphragm pump
or of the pump head, the shut-off-chamber volume is 1% to 50% of
the product-side pumping-chamber volume, preferably 1% to 30% and
particularly preferably 1% to 15%. In principle, this feature may
also be applied to a diaphragm pump according to copending
application Ser. No. 10/383,954.
[0041] The center-to-center distance of the respectively adjacent
inlet and outlet of each pumping or shut-off chamber is two to ten
times the largest hydraulic diameter of the respective inlet
orifice (240) or outlet orifice (241), preferably the
center-to-center distance is two to five times and particularly
preferably twice to three times the hydraulic diameter of the
largest of said orifices.
[0042] The defined center-to-center distance is an important
functional dimension of the chambers. It ensures a leak-tight
closing of the supplying and discharging ducts or orifices and
increases the reproducibility of the conveyance of gaseous or
liquid substances and influences the degree of miniaturization.
[0043] In a preferred version, the connecting ducts (208, 209)
between the pumping chamber and the shut-off chambers are of
straight design and have a ratio of the duct length to the
respective hydraulic diameter of the ducts of at most 20,
preferably at most 10, particularly preferably at most 5.
[0044] A further particularly preferred form of the diaphragm pump
or of the pump head is characterized in that the connecting ducts
and portions of the inlet and the outlet ducts are at an angle
.alpha. with respect to a line that is perpendicular to the plane
of the face of the plate in which they are formed, the angle
.alpha. being in a range of +/-20 to 70 degrees, preferably in the
range of +/-30 to 60 degrees (FIG. 3b). The angle .check mark. is
measured from the deepest point of the depression to the connecting
duct or inlet duct our outlet duct (FIG. 3b).
[0045] The ducts and duct portions which are at an angle reduce
flow losses during the intake and the conveying operation. A
pressure-loss reduction is particularly advantageous, because flow
processes in the diaphragm pump according to the invention or in
the pump head are initiated by abruptly changing variations in
pressure and vacuum. In principle, this feature may also be applied
to a diaphragm pump/pump head according to copending application
Ser. No. 10/383,954.
[0046] The small dead-space volume between the pumping and the
shut-off chambers improves the intake capacity of the diaphragm
pump or of the pump head.
[0047] A further particularly preferred form of the diaphragm
pump/pump head is characterized in that the pump head is comprised
of at least three plates and at least one outer plate is designed
to be thermally controllable. In principle, this feature may also
be applied to a diaphragm pump/pump head according to copending
application Ser. No. 10/383,954.
[0048] The thermal control of the outer plate takes place by
thermostat control or by electrical heating combined with a cooling
device.
[0049] The present invention preferably relates, moreover, to a
diaphragm pump with controllable valves and with a decentral
control unit, characterized in that in the pump head, in the
throughflow direction of the fluid, the inlet duct with a
throughflow shut-off chamber and with connecting duct to the
pumping chamber has a larger hydraulic cross section than the
discharging connecting duct with a following shut-off chamber and
outlet duct.
[0050] The present invention relates particularly preferably to a
diaphragm pump with controllable valves and with a decentral
control unit, characterized in that, in the pump head, the volume
of the pumping chamber (211) is in the range of 0.005 ml to lower
than 1000 ml, preferably 0.01 ml to 100 ml, and, particularly
preferably, the volume of the pumping chamber is 0.1 ml to 10
ml.
[0051] The present invention relates in a very particularly
preferable way to a diaphragm pump with controllable valves and
with a decentral control unit, characterized in that, in the pump
head, the dead-space volume of the product space of the pumping
chamber (211) is 0.1% to 20%, preferably 0.1% to 10% and
particularly preferably 0.1% to 5%.
[0052] An increase of the performance by combining in a compact
style for example two pump heads with controllable valves and with
a decentral control unit, comprised of three plates, and
depressions located in the parting planes of the plates and having
common inlet and outlet ducts and angled connecting ducts between
the pumping and shut-off chambers is possible if in the middle
plate, one pumping depression (303, 303') and at least two shut-off
chambers (301, 305) are introduced on each side, and the inlet duct
issues in the intaking throughflow direction onto a connecting duct
which connects two shut-off chambers (301, 301'), and, in a
discharging flow direction, the connecting duct likewise connects
two shut-off chambers, and, via the outlet duct, a feed material
can emerge from the pump head, and, in conjunction with the
decentral control, the actuation of all the pumping and shut-off
chambers is linked in such a way that the function of a double
diaphragm pump with controllable valves is fulfilled (FIG. 3a).
[0053] The shut-off chambers assigned in each case to a pumping
chamber must in this case be activated with a time offset in the
control sequence, so that the pulsations which arise are
halved.
[0054] The three plates of this diaphragm pump according to FIG. 3a
are preferably releasably connected to one another for cleaning and
repair purposes.
[0055] A further preferred form of the diaphragm pump is
characterized in that the pump is comprised of at least three
plates and at least one pumping chamber is provided in the middle
plate (FIG. 4 or FIG. 4a), and at least three smaller shut-off
chambers belong to each pumping chamber and each shut-off chamber
possesses a connecting duct to the pumping chamber and an inlet
duct or outlet duct for the supply or discharge of at least one
fluid, and all the chambers can be activated separately via a
decentral control unit.
[0056] A diaphragm pump for example consisting of a pump chamber
with at least three shut-off chambers allows the sequential or
alternating conveyance of at least two different fluids. Thus, for
example, two different substances can be supplied to a process by
means of one pump, in which case the stroke ratio of the feed
substances may be identical or different.
[0057] The benefits to the user are that, with one metering unit,
at a low outlay in terms of investment and of assembly, and also
with the least possible amount of space required, a plurality of
substances can be supplied in a desired ratio to a process by means
of one pumping unit. Particularly in applications in the
pharmaceutical sector where low dead-space volumes and a
sterilizability of the technical components used are required, it
is particularly advantageous to employ the diaphragm pump according
to the invention.
[0058] In an alternative embodiment, the diaphragm pump according
to the invention or the pump head according to the invention is
used as a conveying device. In this case, the diaphragm pump
according to the invention or the pump head according to the
invention is suitable for a sampling of liquids or gases from
closed appliances.
[0059] FIG. 7 illustrates by way of example a pump circuit for
sampling and sample preparation. Two diaphragm pumps (700, 700')
equipped with a middle plate (400, 400') according to FIG. 4 are
combined with a mixing chamber (701), so that all the functional
parts are introduced in the three, albeit enlarged, pump plates.
The diaphragm pumps have a pumping chamber (702, 702') and each
pumping chamber has four associated shut-off chambers (703, 704,
705, 706 and 703',704',705',706'). The shut-off chambers are
assigned in each case inlet ducts and outlet ducts (identified by
flow arrows in the figure). FIG. 7 illustrates all components for
automated sampling with subsequent processing and transport away to
a connected analyzer. An illustration of the control unit for the
separate activation of the chambers and a sectional illustration of
the three plates have been dispensed with.
[0060] It can be seen from FIG. 7 that a substance sample can be
sucked up when the inlet duct (707) and the outlet duct (708) are
connected to a reactor. A substance quantity can be constantly
pumped around from the reaction vessel via the inlet duct (707),
intake valve (704), pumping chamber (702), delivery valve (705) and
outlet duct (708) of the pump (700). The control, for example,
changes over at a desired time, so that the delivery valve (705)
closes and the valve (706) opens and a defined substance quantity
is transferred through the outlet duct of the valve (706) into the
mixing chamber (701) by means of the known pumping-chamber volume.
As soon as the sample is transferred, the pump (700') starts in
order likewise to generate pumping-around circulation to the mixing
chamber. In this case, the inlet duct of the valve (704') and the
outlet duct of the valve (705') are connected to the mixing
chamber. Then, in parallel with the operative pumping-around
circulation of the mixing chamber, the pump (700) can, via the
inlet duct (709) and the valve (703), with the valve (704) closed
at the same time, convey into the mixing chamber an additional
diluting agent which is mixed with the substance sample there.
After the mixing process by means of the pump (700'), the diluted
substance sample is conveyed to a possible analyzer. In this case,
the valve (705') closes and the valve (706') opens. By virtue of
the sum of all the supplying pump strokes to the mixing chamber,
with the same number of strokes the prepared sample can be
transferred out via the outlet duct (710) and, if appropriate,
conveyed for analysis. Furthermore, the inlet duct (709) is
extended as far as the valve (703'), so that, after the sample
transport, the second pump can also be scavenged by diluting agent
when corresponding valves are switched.
[0061] The conveying device has a low dead-space volume.
[0062] This low dead-space volume is necessary so that the
deposition and ageing of extracted substances do not falsify the
analysis result due to old substances which otherwise clog the
product-receiving ducts, and high operational availability is
afforded.
[0063] The conveying device according to the invention allows exact
sampling and a near-user volumetric conveyance of liquids, gases or
liquefied compressed gases. It is particularly advantageous for
these purposes because the stroke volume of the pump head can
easily be adapted to operational requirements.
[0064] The diaphragm pump/conveying device according to the
invention is operated by means of a decentral electropneumatic
control unit.
[0065] However, a decentral electropneumatic control unit, as in
FIG. 1, also allows a synchronous activation of a plurality of pump
heads. The parallel operation of the plurality of pump heads by
means of only one control unit allows the efficient use of the
diaphragm pump/conveying device according to the invention, for
example, in decanting systems of all decanting appliances. The
invention therefore also relates to decanting systems or decanting
appliances which contain at least one diaphragm pump according to
the invention.
[0066] A decentral electropneumatic control unit also permits a
time-offset activation of individual pump heads, so that, when a
plurality of pumps are operating in parallel, reduced pulsation
occurs.
[0067] By means of the diaphragm pump according to the invention
with a decentral electropneumatic control unit and with an
adjustable disc in the control space of the pumping chamber,
efficient use, at the same time with low investment costs, is
possible. This becomes particularly clear when changing tasks
demand conveying streams of different size which cannot be covered
by one type of pump head. In the case of conveying streams of
different size, only the pump head has to be exchanged, while the
control part remains unchanged. The exchange of the pump head takes
place simply by the unclamping of the pneumatic control lines.
[0068] The control for conveyance by means of the diaphragm pump is
preferably carried out in such a way that a conveying stroke
consists of at least four individual successive control steps and
each individual control step is separated from the following
control step by means of an intermediate or associated constant or
variable time element, and the delivery or the metering capacity of
the pump can be varied by the variation of at least one time
element.
[0069] The time elements interposed between the control steps
ensure that the pneumatically triggered part-steps of the pumping
stroke are carried out exactly and fully and the individual steps
take place reproducibly. The synchronous variation of all the time
elements for regulating the delivery capacity ensures a simple
operator-friendly handling of the pump.
[0070] The time elements T belonging to the control amount
preferably to 0.001 seconds to 100 seconds, preferably the range is
between 0.03 seconds and 30 seconds, and, particularly preferably,
the time element amounts to 0.03 seconds to 10 seconds.
[0071] The time elements ensure that the high-speed electronic
control signals (signal transit time), the slower pneumatic
operations for deflecting the diaphragms and consequently the
hydraulic displacement operations on the product-touched side of
the diaphragm are not discontinued prematurely. Particularly when
viscous substances with a viscosity of 0.1 mPas to 5000 mPas are
being conveyed, the fluid-dynamic operations require more time than
the electronically triggered signals of the control.
[0072] The metering cycle preferably consists of at least four
control steps and has at least two different time elements, of
which only one time element is variable and is used for regulating
the pumping cycle.
[0073] For the time optimization of the pumping cycle of a
diaphragm pump according to the invention, the pneumatic opening
and closing operations of the diaphragms in the shut-off chambers
may be provided with a non-adjustable smaller time element and a
variable time element may be used for the OPEN/SHUT switching of
the middle larger pumping chamber.
[0074] Two different time elements are advantageous particularly
when the volume of the shut-off chambers is smaller than the volume
of the pumping chamber.
[0075] Particularly on the basis of the electropneumatic control
and the changing pneumatic states in the control lines and control
spaces of the diaphragm pump, between the vacuum or a pressureless
state of the opening operation and an increased pressure of the
closing operation of the chambers, it is advantageous to operate
with different time elements and thus increase the performance of
the pump.
[0076] In a particularly preferred operating mode, each time
element is larger than the required switching time of the
associated electropneumatic multi-way valves in the control
unit.
[0077] In a particular version of the control, the associated time
element for the diaphragms of the shut-off chambers is 0.01 to 0.15
seconds and preferably 0.01 to 0.075 seconds and particularly
preferably 0.01 to 0.05 seconds.
[0078] Preferably at least two diaphragm pumps are connected in
parallel to the electronic and the electropneumatic control
unit.
[0079] An electropneumatic control unit can activate a plurality of
diaphragm pumps in parallel, so that the pumps can synchronously
meter different substances in different quantities simultaneously
by means of pumping chambers which, if appropriate, are of
different sizes.
[0080] The thickness of the elastic diaphragm is preferably larger
than 0.1 mm and smaller than 5 mm and the height of the pumping and
shut-off chamber in the region of the vertex of the chamber
(greatest extent across the diaphragm) is particularly smaller than
10 times the diaphragm thickness.
[0081] Materials such as plastics and elastic diaphragms undergo
dilation and permanent deformation under stress. This permanent or
plastic deformation has direct effects on metering accuracy, in
particular in relation to the individual metering stroke. For
precision metering using diaphragm technology it was found in tests
that the movement of the diaphragm and thus the height of the
shut-off chambers and pumping chambers cannot be of unlimited
desired magnitude.
[0082] In course of the present invention it was surprisingly found
that, starting from the fixed, non-stressed diaphragm state up to
the maximum stressed diaphragm state narrow limits have to be
observed between the plates in order to allow the exact metering of
the liquid concerned.
[0083] In the case of a pumping chamber geometry such as for
example in the shape of a spatial spherical segment, the maximum
diaphragm dilation or deformation is determined by measuring the
change in length between the chord length and the arc length of a
spherical segment. The diaphragm is not stressed at the level of
the chord of the spherical segment and is stressed at the level of
the arc length of the spherical segment. Based on the chord and arc
length of the spherical segment, the width and the maximum height
of the spherical segment and thus the volume of the pumping
chambers and shut-off chambers can be mathematically determined
(cf. FIG. 8). This method of determination can be applied
analogously to other pumping chamber and shut-off chamber
geometries.
[0084] The maximum deformation of the diaphragm into the larger
product-side depression must be no more than 20%, preferably no
more than 10%, and more preferably the deformation should be less
than 5%, in order to obtain consistent high diaphragm movement and
high metering accuracy, and in particular short-time accuracy.
[0085] The diaphragm deformation limits identified therefore
determine the heights of the shut-off chambers and pumping chambers
formed by the diaphragms, so that the metering accuracy of the
diaphragm pump according to the invention is improved
considerably.
[0086] The concave depressions in the plates may have various
geometric shapes, such as, for example, that of a cylinder, of a
spherical segment or of a cone frustum.
[0087] The diaphragm pump or the pump head preferably has smaller
depressions for the suction-side and delivery-side shut-off chamber
than for the pumping chamber, and all the depressions are arranged
completely on the product side of the diaphragm side in the middle
plates.
[0088] A variant of the diaphragm pump or of the pump head is
preferably comprised of a pneumatically controlled pumping chamber
combined with two magnetically operated valves as shut-off
chambers.
[0089] The diaphragms used in the diaphragm pump or in the pump
head are preferably designed to be larger in diameter than the
diameter which is formed by the chambers in the parting plane of
the plates, and the diaphragm diameter is particularly preferably
at least 20% larger.
[0090] In a further alternatively preferred embodiment, metallic
diaphragms are used as a pumping diaphragm and are introduced or
are connected unreleaseably to one of the plates, in particular an
outer plate, by welding.
[0091] In a further particular embodiment, a pulsation damper is
mounted downstream of the delivery-side shut-off chamber in the
direction of flow, particularly in the region of the outlet duct of
the diaphragm pump or of the pump head.
[0092] In a further particular embodiment, the diaphragm pump or
the pump head is equipped with an integrated spring-loaded overflow
valve, in order to generate internal product circulation in the
pump head. If the connected control pressure is higher than the
desired pump pressure, an integrated possibility of expansion from
the pump delivery side to the pump suction side is provided.
[0093] In a further particularly preferred version, at least two
pump units, comprised of two pumping chambers with four associated
shut-off chambers, are arranged next to one another in the three
rigid plates so as to form a pump set.
[0094] The subject of the invention is also a pump set comprised of
two or more diaphragm pumps, the diaphragm pumps according to the
invention having a common control unit.
[0095] A pump set in which the pump heads have common continuous
plates is preferred.
[0096] In a preferred embodiment, the present invention relates to
a diaphragm pump which is used as a controllable multi-duct
diaphragm valve consisting of three plates, characterized in that a
distributor chamber is connected to an inlet duct via a connecting
duct having at least one shut-off chamber which has an outlet duct,
and the chambers have depressions of identical size and can be
activated separately, so that, for the passage of a material, at
least two chambers must be opened simultaneously in the desired
throughflow direction, and all the chambers are actuated by a
decentral electropneumatic control unit.
[0097] The diaphragm pump according to the invention is suitable as
a multi-duct diaphragm valve particularly for the uniform
distribution of liquids and gases to a multiplicity of consumers,
since it has a compact form of construction, the smallest possible
dead spaces and, by virtue of the small control spaces, short
switching times to pass from the OPEN position into the SHUT
position.
[0098] With the inlet duct of the distributor chamber closed, the
diaphragm pump according to the invention, as a multi-duct
distributor valve, can be used as a distributor valve in order to
guide two different liquids to a multiplicity of offtake points of
the distributor valve. In this case, for example, at least two
shut-off chambers are connected to different fluid supplies, so
that distribution is possible via the central distributor chamber
to a multiplicity of, but at least more than two, shut-off chambers
with associated outlet ducts. In this case, three chambers are
opened for sequential fluid passage. In the state of rest, at least
two chambers of the multi-duct distributor valve are closed (FIG.
6a ).
[0099] When the diaphragm pump according to the invention is used
as a multi-duct distributor valve for the distribution of at least
two different fluids to a plurality of consumers, reference may
also be made to transmitting and dispensing shut-off chambers.
[0100] This ensures that, in the state of rest, there is an
additional safety shut-off between a plurality of separate
transmission ducts and a plurality of separate reception ducts.
[0101] In the diaphragm pump itself or in case that the diaphragm
pump is used as a multi-duct distributor valve, the actuation of
the diaphragms into the OPEN or SHUT position may take place
pneumatically, electrically or by means of a hydraulic fluid.
[0102] By means of the diaphragm pump according to the invention
with an activatable intake and delivery valve or an intake-side and
a delivery-side shut-off chamber, very small volume flows of <5
.mu.l/stroke, but also higher volume flows into the ml range per
stroke, can be conveyed in a reproducible way, depending on the
design size. The separate set-up between the actual pump unit or
pump head and the decentral electrical or electropneumatic control
unit is particularly advantageous. As a result, the amount of space
required for a continuously operating conveying apparatus in, for
example, a high miniaturization test installation for screening
work is very small. This pump principle works without mechanical
gearing, and the required structural parts of the pump head have no
dynamic function, with the exception of the deflection of the
diaphragm in the region of the shut-off and the pumping chamber.
Thus, even for a miniaturized version of the pump components, there
is no need for precision manufacture. Owing to the absence of
mechanical parts, there are no mechanical disturbing influences,
and the manufacturing costs for this reproducibly operating
diaphragm-pump head are minimized considerably. The pump requires
merely a power and a compressed-air supply so as to be capable of
working; these are present, for example, in any laboratory.
[0103] It is particularly advantageous to use the diaphragm pump
for the metering of very small quantities of liquid substances, of
which the volume per pumping stroke lies appreciably below the
specific drop size. By the pneumatic conveying energy being applied
to the control side of the displacement diaphragm of the pumping
chamber quickly, the intake product volume in the pumping chamber
is thrown out of the product space of the chamber and to the outlet
duct and no drop is formed at the discharge point of the pump. As a
result, a metering of small liquid quantities into a reaction
mixture is not delayed in time and a synthesis process is started
synchronously with the metering.
[0104] The metering of small quantities of substances against a
pressure applied in the opposite direction can be carried out very
effectively, since the diaphragms of the shut-off chambers and the
pumping chamber are elastic and close the supplying and discharging
product ducts in a gas-tight manner when the chambers are in the
SHUT position, so that no material is forced back onto the inlet
side of the pump via the outlet side of the pump head by means, for
example, of the gas phase of a connected pressure vessel, and
intake under normal pressure is not interrupted.
[0105] A further advantage, as compared with the prior art, is
that, by virtue of the small dead space and the leak-tight shut-off
and pumping chamber, a sensitive product to be metered is supplied
to the intended location without a long dwell time and
remixing.
[0106] Advantages are afforded particularly in comparison with
microstructure technology. Since the duct dimensions are large in
relation to the metering volume, the pump is relatively insensitive
to contamination. A fault which is caused by a product impurity and
becomes noticeable due to an increasing metering error or which may
lead to the failure of the metering of the pump is greatly reduced
on account of the large product ducts. Product impurities can be
flushed through the relatively large product ducts during the
metering.
[0107] The extremely low hold-up of the pump head and the small
dead-space volume ensure a good intake behavior and a rapid
reproducible metering, particularly in applications relating to new
pharmaceutical materials which are available only in small
quantities at the early development stage.
[0108] The establishment of small streams of liquid is particularly
simple, because the setting of the metering quantity, along with a
constant displacement volume, takes place by means of an interposed
time element in the control. Volume flows can thereby be varied in
a very simple way without cross-checking. The variation in the
metering capacity of a diaphragm-pump head is carried out by the
metering stroke being shifted on a time axis.
[0109] The lamella-like construction of the diaphragm pump with
integrated controllable valves, which generates a pulsating
metering stream by virtue of the pumping principle, makes it
possible to equalize the metering stream by a multiplication of the
displacement unit and of the valves, the structural dimensions of
the pump in the test installation not being increased
appreciably.
[0110] Further design variants for the mobile use of the diaphragm
pump according to the invention are possible when the controllable
valves are replaced by electro-magnetically controlled valves
(supply voltage, for example, 6 for 12 volts). In mobile uses, the
control unit can then be supplied with power via a battery, so that
the control unit remains operative for a long time. The
pneumatically operated working diaphragm for the conveyance of
liquid substances may be supplied with a portable compressed-air
accumulator which, for reasons of weight, may be made, for example,
from plastic. The diaphragm pump according to the invention, the
pumping chamber of which has a small control-space volume, can be
operated for a long time via the compressed-air accumulator. The
inventive diaphragm pump is appropriate for mobile uses, for
example in the discharge of plant protection agents in difficult
terrain.
[0111] Further operational benefits for the user are afforded in
that the wearing parts which come into contact with product can be
replaced simply and cost-effectively.
BRIEF DESCRIPTION OF THE DRAWINGS
[0112] The invention is explained in more detail below, by way of
example, with reference to the figures.
[0113] FIG. 1 shows the diagrammatic set-up of a pneumatic
diaphragm pump of lamella-like construction, with an associated
electropneumatic control unit and a programmable electronic control
and with connecting lines.
[0114] FIG. 2 shows a sectional illustration of a pump head with an
externally variable wall in the control space of the pumping
chamber.
[0115] FIGS. 2a, 2b show various design contours of the variable
control-space wall (axially movable disc).
[0116] FIG. 3 shows a chambered pump diaphragm.
[0117] FIG. 3a is a sectional illustration, the middle plate having
two pumping chambers and associated shut-off chambers and the outer
plates being equipped with a variable control-space wall (axially
movable disc).
[0118] FIG. 3b shows a diagrammatic pump head with oblique
ducts.
[0119] FIGS. 4, 4a show the middle plate of a diaphragm-pump head
with a plurality of shut-off chambers and a plurality of inlet and
outlet ducts.
[0120] FIG. 4b shows diagrammatically a diaphragm-pump head with a
central pumping chamber and with a plurality of shut-off chambers
and associated inlet and outlet ducts.
[0121] FIG. 5 shows a multi-way diaphragm distributor valve in a
sectional illustration.
[0122] FIG. 6 is a diagrammatic illustration of a multi-way
distributor valve.
[0123] FIG. 6a illustrates diagrammatically a multicomponent
distributor valve.
[0124] FIG. 7 shows an integrated sampling system with two
diaphragm pumps.
[0125] FIG. 8 shows schematically the two-dimensional area of a
spherical segment having different diaphragm deformation
states.
EXAMPLES
Example 1
[0126] FIG. 1 illustrates a diaphragm pump with a pump head (200)
in cross section, with an associated control (100) and casing and a
pneumatic distributor (115). In the pump head according to FIG. 1,
a movable disc (1001) a firmly connected rod has been inserted to
allow a manual adjustment of the movable disc. Electronic
components and a freely programmable electrical control are
installed in the casing. A power supply line, not illustrated,
serves for the voltage supply of the electronic components. The
casing has a display (101), an on/off switch (102) and a plurality
of function keys (103 to 109), by means of which required
parameters for the pumping sequence or for the pumping operation
can be entered, tracked visually and stored. The electronic control
(100) allows various operating variants, so that a switch can be
made to the continuous operation of the pump by means of the key
(103), and to the discontinuous operation of the pump by means of
the key (104). In particular, the discontinuous operation of the
pump can be set by means of a preselectable number of pump strokes
and be stored in the control by means of the key (105). A reduction
in the set parameters is obtained by means of the key (106), and
the key (107) is provided for increasing the variable parameters
which can then be stored, likewise by means of the key (105), in
the control as newly selected operating parameters of the diaphragm
pump. In the continuous operating mode, the time constants can be
varied by means of the keys (106, 107). The key (108) makes it
possible to choose between internal and external control, for
example by an external process management system. The pump head
(200) starts to operate when the key (109) is actuated and, with
the repeated pressing of the key (109), the operation is stopped
again. The electronics together with the programmable control
transmit, at the start of the metering, via electrical connecting
cables (110), digital signals to the electropneumatic multi-way
valves (111, 112, 113, 114), which are then switched into their
defined open or shut position (Table 1). The electropneumatic
multi-way valves (111 to 114) are mounted on a pneumatic
distributor block (115). The distributor block has two supply ducts
(116, 117). The supply duct (116) is connected directly to the
compressed-air supply and the distributor duct (117) is connected
to the vacuum supply by means of a vacuum line. The vacuum is
generated by the vacuum generator (118), an injector, which is
installed in the bypass and which is constantly supplied with
compressed air by the valve (114) when the electrical control is
switched on. In a compact form of construction, the distributor
block (115), together with the electropneumatic 2/3-way valves and
the vacuum generator (118), is located directly in the casing of
the control (100), so that the compressed-air supply of the supply
duct (116) is connected via a hose coupling (116') and the pump
head is connected via the hose couplings (119', 120', 121'). The
freely programmable electropneumatic components, diodes for the
visual function indicator, electrical power pack and an electrical
board are not illustrated in FIG. 1.
[0127] The freely programmable control of the pneumatically
operated diaphragm pump with a pump head (200) switches the
electropneumatic multi-way valves (111 to 114) and conducts the
pneumatic pressure, prevailing the distributor block (115), in the
duct (116) (delivery duct) or the vacuum in the distributor duct
(117) (vacuum duct) through the control lines (capillaries or
hoses) (119, 120, 121) to the pneumatic control spaces (pneumatic
spaces) (220, 221, 222) into the pump head (200).
[0128] The valve (111) is connected to the intake valve (lower
shut-off chamber (210) of the pump head (200) by means of the
control line (119). According to the same diagram, the other valve
(112) (upper shut-off chamber (212)) and the valve (113) are
connected to the pumping chamber (211) of the pump head (200). The
valve (114) supplies the vacuum generator constantly with
compressed air and is switched immediately as soon as the
electronics are supplied with electrical voltage.
[0129] The diaphragm-pump head (200) consists of the three
part-plates (201, 203, 205) and has inserted elastic diaphragms
(202, 204) which are pneumatically deformable in the region of the
pumping chamber (211) and shut-off chambers (210, 212). The
diaphragms (202, 204) are somewhat smaller than the plates (201,
203, 205), in order to ensure good sealing-off relative to the
atmosphere. In the plate (203) are introduced depressions which
form the pumping and shut-off chambers (210, 211, 212), the
respective compensating volume of the shut-off chambers (210, 212)
being introduced in the plate (201). The pumping chamber (211) is
incorporated with a smaller compensating-volume fraction in the
plate (205) and with the larger pumping-volume fraction in the
middle plate (203).
[0130] The shut-off chamber (210) designates, for example, the
controllable intake valve of the pump head. The pumping chamber
(211) accordingly represents the conveying chamber and the shut-off
chamber (212) presents the controllable delivery valve of the pump
head.
[0131] The diaphragms (202, 204) divide the pumping and shut-off
chambers into control spaces (220, 221, 222) and into product
spaces (230, 231, 232).
[0132] The pumping and shut-off chambers (210, 211, 212) are in the
form of spherical indentations. The middle plate (203) has an
intake duct (207) and an outlet duct (206). The two ducts (206,
207) are extended in each case by a welded-in capillary. The ducts
(209, 208) connect the product spaces (230, 231, 232) of the
chambers (210, 211, 212) to one another.
[0133] The pumping chamber (211) has a groove (213) as a connecting
element from the lowest geometric point of the depression in the
plate to the outlet orifice or to the connecting duct (209). It
also becomes clear that, between the inlet duct (208) and the start
of the outlet duct (209) with the connecting groove (213), there is
still a sufficient distance to allow leak-tight closing of the
orifices in the product space of the pumping chamber by the
diaphragm (204).
[0134] The pump head (200) is shown here in the control step 4 (see
Table 1). In the region of the shut-off chamber (210) (controllable
intake valve), the diaphragm (202) is acted upon by pressure on the
control-space side (220), so that the diaphragm (202) blocks the
intake duct (207) at the inlet (240) (FIG. 2) and the connecting
duct (208) at the outlet (241) (FIG. 2). In the region of the
pumping chamber (211) (conveying chamber or displacement unit), the
associated control space (221) is acted upon by a vacuum, so that
the actively conveying diaphragm region lifts off and opens the
supplying and discharging connecting duct (208, 209). The shut-off
chamber (212) is likewise acted upon by a vacuum on the control
side, so that the connecting duct (209) and the outlet duct (206)
are opened, in order, in the following control step 5 (see Table 1)
to displace the liquid volume out of the pumping chamber. It can be
seen that the respective diaphragm movement extends over the entire
height of the depression. FIG. 1 does not illustrate the screws
necessary for drawing together the plates and at the same time
pressing together the inserted diaphragms.
[0135] The order of the programmable control steps and the position
of the valves (111 to 114) are illustrated below in Table 1.
Digital signal "1" means that compressed air prevails (result: the
diaphragm is pressed onto the plate (203) and closes) and the
signal "0" means that a vacuum prevails (the diaphragm is raised in
the control space and opens). As soon as the electronic control is
supplied with electrical voltage and is switched on by means of the
key (102), the programmed control switches the valves (111 to 114)
into a defined starting or basic position. The control of a
complete pump stroke consists here, for example, of five individual
steps. When the pumping operating is interrupted or terminated, the
control jumps into the starting or basic position.
1TABLE 1 (112) (111) (113) Pressure (114) Step Suction valve
Displacer valve Vacuum Basic position 1 1 1 1 1st step 0 1 1 1 2nd
step 0 0 1 1 3rd step 1 0 1 1 4th step 1 0 0 1 5th step 1 1 0 1
Back to Step 1
[0136] In the control sequence, a variable time element is
programmed and assigned (not illustrated in Table 1) for each
control step 1-5, so that the individual control steps taking place
in succession do not influence one another and are executed
completely. The switching times of the electropneumatic valves are
longer and therefore substantially slower than the time required
for transmitting the digital signals. By means of the interposed
time elements, the pumping function can be reproduced according to
the control cycle 1-5 (see Table 1) and is performed
completely.
Example 2
[0137] FIG. 2 shows a sectional illustration of a pump head (200)
consisting of the plates (201, 203, 205). What can be seen are the
elastic diaphragms (202, 204) clamped in the parting planes of the
plates, and also the shut-off chamber and the pumping chamber with
the associated depressions (spherical indentation) in the middle
plate. The outer plate (205) is made thicker, so that the control
space (221) is enlarged beyond the associated compensating volume.
The control space is additionally widened by the amount of a
smaller cylindrical depression (1000) and by the amount of a
threaded bore which is led outwards. The enlarged control space has
installed in it the stepped disc (1001) with a one-sided cylinder,
a stepped threaded rod (1002) led through the outer plate being
fastened in the said disc, so that, in the event of even only a
slight rotation of the outer knurled nut (1003) fastened on the
threaded rod (1002), the disc (1001) is axially moved or displaced
in the control space. The threaded rod is stepped and is fastened
releasably to the receiving cylinder of the disc by means of two
pins (1004). A seal (1005) is positioned on the one-sided cylinder,
located in the control space, of the disc, in order to seal
outwardly the control space acted upon by pneumatic pressure. The
disc (1001) is provided with a plurality of bores (1007) and with a
concentrically raised ring (1008), in order to assist the action of
pressure upon the entire control space and to prevent the closing
of the bore (1006) in the event of the complete return of the disc.
The supply of compressed air or action by means of a vacuum takes
places via the laterally offset bore (1006). In FIG. 2, the
adjustable disc has the contour of a spherical segment and is
consequently adapted to the contour of the process-side
depression.
[0138] If the threaded rod is provided, for example, with a
fine-pitch thread, the disc (1001) can be displaced axially in the
event of even only slight manual rotation of the knurled nut (1003)
and the diaphragm travel, which at the same time determines the
liquid volume to be conveyed, can thereby be varied.
[0139] FIG. 2a and FIG. 2b show further design variants, in
particular different contours of the movable disc. The
diaphragm-side contour of the disc (1001') in FIG. 2a is plane,
while the contour of the disc (1001") in FIG. 2b exhibits an obtuse
cone. Furthermore, the two figures show that the disc can be
manufactured with a one-sided cylinder and with a directly
worked-on threaded rod, in order as far as possible to reduce the
number of components, the costs and the assembly work.
Example 3
[0140] FIG. 3 shows by way of example the chambering of a pumping
diaphragm (204) in a sectional illustration. In the upper part of
the figure, the chambered diaphragm (204) is not in the operating
state, while, in the lower part of the figure, the control space
(221) of the diaphragm (204') is acted upon by pressure and the
deflection of the diaphragm occurs. It can also be seen that the
diaphragm is clamped between the plates (203, 205) and parts of the
connecting ducts (208, 209) are present in the plate (203). The
pumping diaphragm is clamped between the plates in the outer
region, while the diaphragm is open in the center, so that chamber
elements (1100, 1101) can be fastened on both sides. The chamber
elements have, towards the elastic diaphragm, a raised rounded
concentric outer ring (1102, 1103), so that the enclosed diaphragm
surface is no longer subjected to force while the chamber elements
are being screwed together.
[0141] It is advantageous if the contour of the process-side
chamber element (1104) is adapted to the depression contour, so
that the dead-space volume of the pumping chamber is not
appreciably increased. If the product-side chamber element is
provided or coated with an elastic film (1105), the connecting
ducts can be closed in a leak-tight manner in the loaded diaphragm
state. In FIG. 3, it can be seen that, in the event of plastic
deformation of an elastomer, the degree of deformation due to the
slight deflection, which is to be seen as a function of the
diaphragm diameter, is negligible. The chamber elements also afford
the possibility of using diaphragm materials which would be less
suitable on account of the high permanent deformation.
[0142] FIG. 3b illustrates diagrammatically a diaphragm pump
consisting of three plates (201, 203, 205), and it can be seen, in
particular, that connecting ducts (208, 209) and portions of the
supply and outlet duct (207, 206) are at an angle .alpha., so that
no great pressure losses occur during rapidly changing flow
states.
Example 4
[0143] FIG. 3a shows a double diaphragm pump with controllable
valves, which consists of three plates, and all the pumping and
shut-off chambers have been introduced in the middle plate. It can
be seen that the inlet duct (300) has a T-shaped configuration and
connects the left-hand and right-hand intake-side shut-off chambers
(301, 301'), so that the two shut-off chambers have a common inlet
duct. An angled connecting duct (302, 302') runs from each shut-off
chamber to the pumping chamber (303, 303'). The downstream outflow
region of the double diaphragm pump is configured almost
mirror-symmetrically to the inflow region. The connecting ducts
(304, 304') connect the pumping chamber (303, 303') to the shut-off
chambers (305, 305') on the outlet side, and the shut-off chambers
of the outlet side are connected to a common outlet duct (306). In
this example, a double diaphragm pump is described, with a split
inner passage duct. In this example, the double diaphragm pump is
equipped with a movable disc (1001) for possible part-stroke
operation. No releasable connecting elements of the plates are
shown in FIG. 3a, and the pump head is not in an operating state.
The throughflow direction of the double diaphragm pump is indicated
by arrows.
Example 5
[0144] FIGS. 4, 4a show front views of a middle plate (plate 400),
in which four shut-off chambers (1200, 1201, 1202, 1203) are
assigned to a pumping chamber (1205). The chambers are formed by
depressions in the shape of a spherical segment (spherical
indentation). Each shut-off chamber has a connecting duct (1206) to
the central pumping chamber (1205), and, in addition, in each case
two shut-off chambers are provided with a separate inlet duct
(1207, 1208) and two shut-off chambers are provided with a separate
outlet duct (1209, 1210). In this exemplary embodiment, two
different substances can be conveyed sequentially or alternately by
means of one pump head. In an application for pharmaceutical
purposes, the second inlet duct could also be used to pump a
cleaning liquid and to initiate a scavenging operation. There is an
alternative use for the second inlet duct when a steam connection
is made and a sterilizing operation could thereby be initiated at
any time. Thus, for example, the inlet duct (1207) may be connected
to a supply line for a substance to be metered. During the intake
operation, the substance passes into the pumping chamber (1205), in
order then to be forced through the shut-off chamber (1202) into
the outlet duct (1209). A sterilizing operation requires a steam
connection on the inlet duct (1208). The steam could pass through
the shut-off chamber (1201) into the pumping chamber 1205), in
order subsequently to pass through a connecting duct to the
shut-off chamber (1203) and to the outlet duct (1210). In the
pharmaceutical field of use, metering or pumping operations and
sterilizing steps take place sequentially, so that, by virtue of a
separate activatability of the pumping chamber and shut-off
chambers, the outlay in terms of automation is low. FIG. 4 shows an
angled connecting groove (1215) in the pumping chamber (1205) and
bores (1216) for receiving ties or releaseable fastening elements,
by means of which all three plates can be fastened. FIG. 4 clearly
shows the pumping chamber, connecting ducts (for example 1206) and
a groove (1215) for better product discharge from the pumping
chamber. FIG. 4a clearly shows the shut-off chambers with inlet and
outlet orifices.
[0145] A chamber circuit is illustrated diagrammatically by way of
example in FIG. 4b, a pumping chamber (1205) and six shut-off
chambers (for example 1200), illustrated in the figure as a circle,
and also associated inlet ducts (1207, 1208, 1213) and outlet ducts
(1209, 1210, 1214) being interlinked. By virtue of the separate
activation of each individual chamber, a plurality of different
fluid streams can be connected sequentially or alternately to all
the existing outlet ducts via a common pumping chamber (1205).
[0146] It can be seen from FIGS. 4, 4a and 4b that a pumping
chamber with more than three shut-off chambers and with the
corresponding inlet and outlet ducts can be used for an automated
sampling system. Thus, for example, bypass pump-around circulation
can be generated from a reactor or a product-carrying pipeline via
the inlet duct (1207) which the shut-off chamber of the pumping
chamber (1205) and the outlet ducts (1209). If a substance sample
from the reactor is desired at a specific time, for example, the
outlet duct (1209) closes and the outlet duct (1210) opens, so that
a sufficiently large substance quantity can be extracted as a
sample via the pumping chamber (1205). After the sampling, the
pumping chamber is cleaned by means of an inert scavenging agent
via the inlet duct (1208), in which case the cleaning liquid can be
discharged separately via the outlet duct (1214). The inlet duct
(1213) is provided, for example for a final sterilizing operation
after the termination of the reaction.
Example 6
[0147] FIG. 5 illustrates a multi-way distributor valve consisting
of three plates and analogous to the pump construction. It can be
seen, furthermore, that elastic diaphragms (1303, 1304) are clamped
between the plates (1300, 1301, 1302) and thereby divide introduced
depressions in the middle plate into a product space and a control
space. In this illustration, the control spaces of the chambers are
not widened, so that the diaphragms bear on the outer plates in a
leak-tight manner in the parting region. Pneumatic connections
(1305, 1306, 1307) through the outer plates (1300, 1302) are
indicated by double arrows. The distributor valve is illustrated in
the open state, so that, for example, the elastic diaphragms would
be deflected by an applied pneumatic pressure and would thereby
close the connecting ducts. When the pneumatic pressure is
released, the connecting ducts in the product chambers are opened,
so that a fluid can flow through. FIG. 5 shows a multi-way
distributor valve which has a central inlet duct (1308) in the
outer plate (1300), followed by a connecting duct (1309) to the
distributor space (1310). The distributor space has two connecting
ducts (1311, 1312) to smaller shut-off chambers (1313, 1314) which,
in turn, have outlet ducts (1315, 1316) for the fluid discharge. It
can be seen that, for example, a connected electropneumatic control
unit must activate at least two chambers in order to release a
switching travel for the passage of a material. In this example,
the multi-way distributor valve or the distributor valve can guide
a supplied material selectively to the left-hand outlet duct (1315)
or to the right-hand outlet duct (1316). For cleaning purposes, the
two outlet ducts can be opened simultaneously, so that parallel
distribution is possible. The electropneumatic control unit does
not require a vacuum generator, because, as a rule, fluid supplies
have an initial pressure.
[0148] In the parting plane of the plates (1301, 1302), the
connecting ducts are worked on one side into the surface of the
plate (1301), so that all the connecting ducts are sealed off
relative to one another and outwardly simultaneously by means of
the inserted large-area diaphragm. Multi-way distributor valves are
therefore preferably provided with full-area elastic films in the
parting planes of the plates, in order to achieve simpler assembly
and, where cleaning is concerned, to simplify the operations. Due
to the central supply of a material which is to be distributed, a
circular orifice is provided in the elastic film (1303), so that
the inlet duct (1308) and the connecting duct (1309) have a
through-flow connection.
[0149] The distributor chamber and the shut-off chamber can be
activated pneumatically, for example by means of compressed air, or
hydraulically by means of fluid. However, electromagnetic drives
may also be used. The plates of the multi-way distributor valve are
connected releaseably to one another.
[0150] FIG. 6 illustrates diagrammatically the middle plate of a
multi-way distributor valve. What can be seen is a central material
inlet duct (1308') with a distributor chamber (1310') and with a
multiplicity of connecting ducts (1312') having associated shut-off
chambers (1314') and following outlet ducts (1316'). With this
version, for example, a fluid can be conducted sequentially or in
parallel to a multiplicity of consumers, in which case two chambers
must always be switched into an open state.
[0151] When the central inlet duct (1308') is closed, as shown in
FIG. 6a, and, for example, two outlet ducts (1400, 1401) are
converted to inlet ducts and connected to different material
suppliers, there is a possibility of guiding these two materials in
series to each connected outlet duct when two shut-off chambers and
the distributor chamber are switched in the open state.
Example 7
[0152] FIG. 7 illustrates by way of example a pump circuit for
sampling and sample preparation, Two diaphragm pumps (700, 700')
are designed with a middle plate (400, 400') according to FIG. 4
and combined with a mixing chamber (701) so that all the functional
parts are introduced in three, albeit enlarged, pump plates. The
diaphragm pumps have a pumping chamber (702, 702'), and each
pumping chamber has four associated shut-off chambers (703, 704,
705, 706 and 703' 704' 705' 706') The shut-off chambers are
assigned in each case inlet ducts and outlet ducts (identified by
flow arrows in the FIG. ). FIG. 7 illustrates all the components
for automated sampling with subsequent processing and transport
away to a connected analyzer. An illustration of the control unit
for the separate activation of the chambers has been dispensed
with.
[0153] It can be seen from FIG. 7 that a substance sample can be
sucked in when the inlet duct (707) and outlet duct (708) are
connected to a reactor. A substance quantity can be constantly
pumped around from the reaction vessel via the inlet duct (707),
intake valve (704), pumping chamber (702), delivery valve (705) and
outlet duct (708). The control, for example, changes over at a
desired time, so that the delivery valve (705) closes and the valve
(706) opens, and a defined substance quantity is transferred
through the outlet duct of the valve (706) into the mixing chamber
(701) by means of the known pumping-chamber volume. As soon as the
sample is transferred, the pump (700') starts, in order likewise to
generate pump-around circulation to the mixing chamber. In this
case, the inlet duct of the valve (704') and the outlet duct of the
valve (705') are connected to the mixing chamber. Then, in parallel
with the operative pump-around circulation of the mixing chamber,
the pump (700) can, via the inlet duct (709) and the valve (703),
with the valve (704) closed at the same time, convey into the
mixing chamber an additional diluting agent which is mixed with the
substance sample there. After the mixing process by means of the
pump (700'), the diluted substance sample is conveyed to a possible
analyzer. In this case, the valve (705') closes and the valve
(706') opens. By means of the sum of all the supplying pump strokes
to the mixing chamber, the prepared sample can be transferred out
via the outlet duct (710) and, if appropriate, conveyed for
analysis by means of the same number of strokes. Furthermore, the
inlet duct (709) is extended as far as the valve (703') so that,
after the sample transport, the second pump can also be scavenged
by diluting agent when corresponding valves are switched.
Example 8
[0154] FIG. 8 schematically shows two plates 800, 801, between
which an elastic diaphragm 802 is fixed. In plate 800 the
product-side pumping space 800' is shown and in plate 801 the
control space 801' of the pumping chamber is indicated. According
to the invention, the membrane movement or membrane deformation
always takes place between the limiting wall of the control space
and the limiting wall of the pumping chamber, so that the maximum
movement of the diaphragm is predetermined by the contours of the
chambers.
[0155] In addition, it can be seen that in the first stress mode,
the diaphragm, which is fixed in the plates and pneumatically
actuated (chord length 807), can be deformed up to the chamber
height 804, whereupon it assumes the arc length 803.
[0156] In the second stress mode the diaphragm is dilated up to the
chamber height 806 with an arc length of 805, so that the diaphragm
is deformed to a considerably greater degree with regard to the
chord length than in the first stress mode. Larger diaphragm
deformations would produce creases, so that the individual
conveying stroke and the displacement volume would be decreased by
the creases which form. In addition, the formation of creases in
the diaphragm prevents the tight sealing of the feed and discharge
cuts in the pumping chambers and shut-off chambers.
[0157] This finding means that the pumping and shut-off chambers
and the diaphragm dilation associated therewith have an effect on
metering accuracy. Where the pumping chamber has optimum dimensions
in an areal shape of a spherical segment having a diameter of about
114 mm and a height of the chamber of about 1.5 mm no permanent
diaphragm deformation occurs. The calculated chord length is about
26 mm and the corresponding arc length are approximately 26.4 mm.
As a result, no permanent deformation of the diaphragm occurs in
this example.
[0158] In the second stress mode the diameter of the spherical
segment is about 26 mm and having the same chord length like in the
first alternative. But the arc length is increased up to about 35
mm. From these data a diaphragm extension of about 34.6% can be
calculated leading to inaccuracies in the metering process.
[0159] In practice the knurled nut (1001) at the disk (1002) is
positioned in that way that there is no deformation of the
diaphragm. During the pumping procedure the diaphragm deformation
into the geometric room of the pumping chamber can be adjusted by
turning the disk via the nut.
* * * * *