Note: Descriptions are shown in the official language in which they were submitted.
26~
This inven-tion relates to a method of and a device for
dispensing viscous concentrates of variable viscosity in accur-
ately metered quantities of variable volume in which cyclic va
riations of the pu~ping volume of a hollow body made of a flex-
ible or elastically deformable material cause said concentrate
to be drawn in from the storage volume of a container via a non-
return valve and to be discharged on the output side via a se-
cond non-return ~alve.
There have been known a variety of metering pumps in
the form of discharging sections provided with two non-return
valves, one of which functions as an inlet valve, the other one
functioning as an outlet valve. For example, there has been dis-
closed in British Patent Specification No. 827,778, a metering
pump in wllich the discharge section is formed by a flexible tube
which is adapted to be closed by the application of a radial
squeezing pressure by means of an actuating device and which tends
again to assume
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lts ~ull open cross-section upon said actuating device belng
Ieleased. Opening of the inlet valve or the outlet valve,
respectively, ls effected by pressure changes caused in said
disch~rge portion. Such a device is not only hard to manipulate
properly but permits only a relatively inaccurate metering ef-
fect to be obtained. Therefore, such devices may be considered
suitable for use with soap dispensers and the like in whlch
metering accuracy is not at a premium. Besides, the means
serving to operate said discharge section are extremely com-
plicated and expensive.
It has further been known to provide a discharging section
with a radially outwardly projecting bellows-like ~old which is
adapted to be compressed in an axial direction between a pair
of plate-shaped actuating elements so as to serve the ~unction
oi a metering pump. In this case it is ~lso possible to construct
the discharging section as a rubber bellows which has associated
therewith suitable beak-like rubber valves ~orming non-return
valves (c~. United States Patent Specification No. 25 54 570).
This known device also occupies considerable space and is, there~
fore, not suitable for ins-tallation in vending machine~s or the
like. The metering volume o~ this known device is also re]atively
inaccurate so tha-t it is extremely difficult to ensure accurate
metering.
~'here it is desired to dispense metered quan-tities of certain
highly viscous concen-trntes, an extremely accurate metering
operation is necessary. In view o~ the iact that in certain
applications, such as beverage vending machines, extremely little
space is available for mechanical equipment, it is necessary to
provide ~ metering device ~hich is o~ as comp~ct design as pos-
sible. A particularly serious problem nrises ~rom -the fact that
concentrntes of perishable organic substances pose great di~-
ficulties as regards the maintenance o~ hygienic conditions,
particularly in cnses in which the metering device and/or
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accessories thereof may be contaminated by drops of such sub-
stances. If all hygienic requirements are to be met, the neces-
sary mnintenance operations and ~requent cle~ning of component
parts prove to be extremely difficult and time-consuming, it
being necessary to provide for constant supervision o~ such
operations.
In the prior-art metering devices comprising a peristaltic pump
or a similar -tube-shaped discharging section, only a relatively
small restoring force is produced upon the elastic tube material
being subjected to small amounts of deformation. The restoring
force is not increased su~ficiently unless a m~jor amount oi
deformation is caused. However, the magnitude oi the restoring
force also affects the accurate reproduceability of the deform-
ation and thus the accuracy of the metering operation. There-
fore, these known devices are only adapted to dispense relatively
large volumes of the concentrate, and the frequency ~ith which
metering cycles can be performed is relatively low. The term
"relatively large volumes" is understood to mean, for example,
volumetric ~uantities o~ 0.4 cubic centimeters. Nor is it pos~
sible to prestress or bias a filled flexible tube sectio~ in its
initial position because it is necessary to thread the tube
sections into an actuating device such as a peristaltic pump,
it being necessary to nvoid any de~ormation in order to prevent
any drops of liquid.
.nother important factor tending to impair the metering accu-
racy of such known devices resides in the ~act that, during a
decrease in the pumping volume, the tube-shaped discharging
section is subjected to uncontrollable additional deformation
caused by the increased pressure occurring ~hithin said section.
~uch uncontrollable variations may onlv be tolerated where a
relatively large metering volume is discharged during each
cycle so that the influence of such variations remains sm~ll.
i
In view of the foregoing, it is an object of this
invention to improve the method described above as well as
the device for practicing said method in such a way as to
avoid the disadvantages thereof and to enable even extremely
small ciuantities of a concentrate to be dispensed in an
extremely accurate manner and at a high cycling frequency.
It is a further object of this invention to provide a device
for pxacticing the method which is of extremely compact
construction so as to permit it to be easily accommodated
in a small space, for example, in a beverage vending machine,
or to permit the device to be installed in existing vending
machines.
According to the present invention there is provided
a method of dispensing viscous concentrates of variable
viscosity in accurately meterable quantities of varying
volume, in which, by varying the pumping volume of a hollow
body made of flexible or shape-retaining resilient material
in the direction of its longitudinal axis between stops,
concentrate is firstly drawn in via a non-return valve at
one end of the hollow body from a storage volume of a con-
tainer and then is discharged at the other end of the hollow
body, wherein the variable portion of the pumping volume of
the hollow body is selected so as to be small with respect
to the smallest quantity to be dispensed; wherein during
the discharge phase the hollow body is supported against
changes in shape in a radially outward direction and is
resiliently pretensioned in its shape corresponding to its
largest discharge volume in an axial direction corresponding
to an increase of its pumping volume; and wherein the pumping
volume is varied cyclically a plurality of times per second
during each dispensing operation.
The present invention also provides a device for
dispensing viscous concentrates of variable viscosity in
accurately meterable quantities of varying volume comprising
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,
,~
a di.spensing section connectible at one end to a container for
the concentrate via a non-return valve and insertable into an
annular actuation device, the dispensing section comprising an
axially movable actua-tion element acting axially on a section
of flexible or shape-retainins resilient material forming a
pumping volume for reducing the volume between stops, wherein
the section forming the pumping volume is arranged as a hollow
cylindrical body in the dispensing section insertable into the
actuation device; wherein the section of the hollow cylindrical
body which can be varied between the stops is formed so as to
be small with respec-t to the quanti.ty to be dispensed in each
case; wherein shape-retaining hollow cylindrical parts are
provided which support the hollow cylindrical body in a
shape-retaining manner against changes in shape. in a radially
outward direction during a volume reduction phase; wherein
the hollow cylindrical body is pretensioned in an initial
position of largest pumping volume with a predetermined force
in the direction of an increase of the pumping volume; and
wherein the actuation element is movable axially in a reciprocat-
ing manner a plurality of times per second by the actuation
device during each dispensing operation.
According to the invention, a pumping effect is pro-
duced by decreasing in an axial direction a cylindrical pump-
ing volume which is supported in a shape-maintaining manner
during the volume reducing operation with the result that
uncontrollable deformation due to the increasing pumping
pressure and changes in the metering volume are avoided. In
this manner it is possible to provide an extremely high
degree of precision of the metering operation even in cases
in which extremely small quantities are dispensed per metering
cycle. The axial compression of the cylindrical metering
volume makes it possible for the hollow cylindrical body
defining the pumping volume to be subjected in its initial
position to a presettable axial bias in the sense of an
increase in said volume. This results in the provision of
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.. ..
~88~6g
sufficiently large restoring forces even wi-th changes in
volume of minimum rnagnitude. Moreover, this axial compression
of the pumping volume i.n conjunction with the extremely high
accuracy capable of attainment even with extremely small
me-tering volumes makes it possible to provide a
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~requency of metering cycles which i5 in agreement with the
power mains frequency, i.e. a frequency of 50 to 60 Hz. This
high cycling frequency and the smallness o~ the quantities
capable of being metered make it possible to vary the total
quantity to be discharged to be selected within a large range
of adjustment simply by suitably controlling the number of
metering pulses per unit time. This method of control can be
implemented in an extremely simple and reliable manner ~lth
mains-frequency controlled devic~s.
Despite the bias which exists in the inoperative position of
the pumping volume, the discharging section can be easily and
reliably threaded in*o the actuating means without drops o~
liquid being dispensed in an undesired manner. At the same time
t~e hygienic problems are completely avoided which might other-
wise be caused by contamination of the device. In addition,
the arrangeJnent just described is improved considerably by the
fact that all components which are of importance as regards
reliable functioning o~ the device are enclosed in a rigid
guiding tube which is either permanently or releasably connected
to a container for shipping, storage and dispensing o~ the
liquid, said contniner preferably being a single-use product.
The high cycling frequency of the device thus permits the liquid
to be dispensed in the form o~ an almost continuous flow or
stream with the aid of a train of rapidly repeated metering
cycles with *he length of said train being capable of being
adjusted to suit requirements.
The sleeve-shaped body of the device need only be o~ flexible
nature, it being possible, by the addition of suitable elements
such as spring elements or the like, to provide for the neces-
sary bias and restoring action. In a preferred embodiment,
however, the sleeve body is made of a shape-retaining elastic
8~269
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mat0rial and secured to rigid hub-shayed bodies of said non-
return valves.
The small dimensions of the dispensing section makes it possible
to install the device in a vending machine in which extremely
little space is available. An additional advantage of the device
of the invention makes it possible to modi~y existing meterin~
devices by the addition of an electromagnetic annular coil for
-the purpose of substituting a quantity controlled or volume
controlled metering method for the time controlled metering
method described ~here time controlled metering would result in
undesirable fluctuations of accuracy due to changes in the
viscosity of the liquid. The metering accuracy of the device
o~ $he invention is not affected by such variations in consist-
ency.
The invention and further particulars will be described more
specifically hereinafter with reference to a preferred embodi-
ment shown in the drawings, in which:-
Figure 1 is an axial cross-sectional view of a container for the
storage, transportation and dispensing of a liquid, -She
container being provided with a dispensing section
according to the invention;
Figure 2 ls an enl~rged exploded cross-sectional view of the
component parts of the dispensing section; and
~igure 3 is an enlarged cross-sectional view of a modified
embodiment of the dispensing section.
Preferably the device of -the invention is manufactured in the
form of a single-use container which is adapted to store, trans-
port and dispense metered quantities of a li~uid. Preferably,
the dispensing section is permanently secured to the container
_7_
during mnnufacture thereo~ and is discarded together with the
container after use. Thus, the con-tainer constltutes a mass-
RrdUced item~
Said container may comprise an external envelope and an interiorflexible bag adapted to contain the liquid and to collapse as
liouid is being withdrawn. l~ith this construction, it is not
necessnry to introduce air into the container to permit liquid
to be dispensed. However, it would a]so be possible to provide
an essentially rigid container with which ventilating means are
associated which are adapted to be actuated for the purpose o~
dispensing liquid.
It should be understood that the container is preferably intended
for the reception, storage and transportation as well as the
dispensing of organic concentrates.
In the embodimen-t shown in Figure 1 the container comprises an
external envelope 1 and a flexible and collapsible li~uid-
receiving container 2 which latter is provided with a mouth-
piece 3 to which the dispensing section 4 ls preferably per-
manently attached. In Figure 1 the container is shown in the
inverted position in ~!hich it is held when it is intended to
dispense metered quantities of a li~uid; In this position, the
dispensing section 6 ex-tends through the central aperture o~ an
electromagnetic annular coil 5 which may, for e~ample, be
fixedly installed in an automatic beverage vending machine.
The electromagnetic annular coil 5 is connected to suitable
control means which make it possible, for example, to operate
the electromagnetic annular coil 5 at the power mains ~requency
~ith the number of oscillations coil 5 is desired to follow
being adjusted with the aid of said control means.
Dispensing section 4 cornprises a rigid tubular guide member
6 made of a plastic material, the upper end of which is
;9
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permanently secured to mouthpiece 3 of the container. As shown
in ~igure 2, tubular guide member 6 is provided with a free
cross section through a major part of lts length forming an
enlarged portion extending downwardly ~rom an annular shoulder
35. The tubular gu~de member 6 has associated therewith a rigid
cover member 26 at its lo~er end, this cover member being pro-
vided with a central discharge spigot 27. In the embodiment
shown the two members G and 26 o~ the tubular guide member are
interconnected by a hub-shaped valve body 20 which is provided
with nn external annular ~lange 22 serving as an abutment up to
which the tubular guide member and the cover member 26 may be
slid over the valve body so as to hold the members in position.
In this arrangement, the hub-shaped valve body 20 is rigidly
connected to both the tubular guide member G and the cover
member 26.
Another similar hub-shaped valve body 8 is received with clear-
ance by the larger-diameter portion of guide member 6 so as to
be capable of-freely moving in an axial direction within guide
member 6. A spigot-shaped terminal portion of valve body 8
made of a plastic material ~acing container l in an upward
direction has attached thereto a magnetizable sleeve member 7
forming an annular armature, the lower annular shoulder of
said sleeve member bearing against shoulder 9 of valve body 8.
Thus, valve body 8 and annular armature 7 constitute a rigid
unit which is axially movable upwardly and downwardly within
guide member 6 as indicated by the double-headed arrow 31.
The mutually facing ends o~ valve bodies 8 and 20 are provided
with receiving and mounting portions 10, 11 and ~9, 21, re-
spectivel~, for the sleeve-shaped end portions 16 and 1~ o~
a hollow cylindrical body 15. In the embodiment shown, body 15
is ~nade of an elastic material so that it also serves the
~unction o~ an elastic spring element. As shown in Figure 2,
body 15 is provided ~lith terminal portions 16 and 18 of greater
326~3
_9
wall thickness serving to mount the two valve bodies 8 and 20
and is also provided with a radially inwardly projecting ~old
or bead 17 of smaller thickness. Body 15 connecting the hub-
shaped valve bodies 8 and 20 de~ines a predetermined metering
volume between the valve bodies. The initial capacity o~ this
volume is determined by the restoring action o~ body 15 in con-
junction with the internal shoulder 35 of tubular guide member 6
on which the annular upper end ~ace o~ annular armature 7 bears
in the rest position.
In the embodiment shown, each o~ the valve~ bodies 8 and 20 ls
provided with a central bore 12 and 24, respectively, into
which there may be spring-fitted a shaft portion of a valve
~lement 14 or 25, respectively~ said valve elements being of
mushroom shape and made of an elastic material. A tapered
~nlargement provided on the free end o~ each mushroom-shaped
portion serves to lock the yalve element to its associated
hub-shaped valve body. The lip-shaped peripheral edge o~ the
dish-shaped head portion of valve element 14 or valve element
25, respectively, is caused by the variable pressure to which
it is subJected to bear sealingly against the adjacent inner
end face o~ -the respective hub-shaped valve body 8 or 20, The
inner portions of said valve bodies are provided with a plural-
ity of passages 13 and 23, respectively, each plurallty forming
a clrcular arrangement, said passages permitting liquid to enter
the metering space and to be discharged therefrom, respe~tively.
Under static conditions, the elastic bias produced by the
material of the mushroom-shaped valve elements 14 and 25 is
sufficient to prevent liquid from ~lowing through passages 13
~nd ~3. Only with pressure variations exceeding such static
conditions will the lip-shaped peripheral edges of the dish-
shaped head portions o~ the,valve elements be li~ted o~ the
central end faces o~ said hub-shaped valve bodies 8 and 20
so as to permit liquid to flow through sald pas~ages.
1. .
.~ fi'9
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The stroke length o~ the assembly ~ormed by valve body 8 and
annular armature 7 in an upward direction is limited by the
internal shoulder 35 o~ tubular guide member 6. In a downward
di~ection the stroke length o~ said assembly is limited by the
iact that durlng such downward motion the lower edge of portion
10 of the hub-shaped valve body 8 comes into contact with the
, annular upper edge'of portion 21 o~ hub-shaped valve body 20.
I ~ithout the design o~ this arrangement being changed, it ~s
possible by suitably selecting the length oi portions 10 and
~1 easily and accurately to adjust the stroke length 30 (Figure
l) o~ the movable assembly 7, 8. As valve body 8 approaches
valve body 20, portions 10 and 21 thereof enclose the hollow
cylindrical body and support it ~rom the outside in such ~ man-
ner that it cannot change its shape, the result being that body
~.5 cannot be expanded in a radial direction.
Figure 1 shows the component parts of the embodiment just
described approximately in their actual size, the stroke length
o~ this pre~erred embodiment being a little smaller than shown
. at ~0 in Figure 1. The liquid volume dispensed through spigot
27 is determined by the number of pumping strokes oc~urring at
the power mains ~requency. Therefore, this volume can be
easily adjusted because the individual quantities discharged
during each pumping stroke can be adjusted in an extrernely
accurate manner even in the case of very small increments.
l~'ithin the dispensing section 4 the liquid i5 hermetically
sealed so as to be protected a.gainst the action o~ atmospheric
o~ygen. It is seen that the arrangement described is capable
o~ being manu~actured in a simple manner and at low.cost, that
it operates in a very reliable manner, that its manipulation is
e~tremel~ simple and sa~e, and that no contamination o~ com-
ponents located in the vicinity o~ the device is possible.
The stroke length may also be limited by means o~ stop members
o~ dif~erent construction which are provided, for example, on
the tubular guide member.
In order to avoid radial deformation of the hollow cylindrlcal
body in the vicinity of the radially inwardly projecting bead
17, it may be o~ advantage to provide the or each bead in the
area o~ 1ts internAlly projecting ridge with a rigid support-
ing ring.
More specifically, it may be of particular advantage to give the
ridge o~ the bead a helical shape. In this case lt is possible
to provide in association with said ridge a supporting element
in the form of a helically extending spring element which is
~dapted to be compressed in an axial direction only, said spring
element serving the additional function of a~ially biassing the
hollow cylindrical body 15. In the latter case body 15 need not
be of a shape-elastic nature if it is made of a material having
a sufficient degree of flexibility.
Under certain conditions it is possible to dispense with the
non-return valve 25 provided on the discharge end o~ the device.
In this case the non-return valve at the exit of the pumping
volume is replaced by a discharge spigot which is in unobstructed
connexion with the pumping space. The inner diamter and the
length o~ such a discharge spigot are so selected that the inner
friction and the surface tension o~ the concentrate present in
the discharge spigot suffice to retain the concentrate column
in its axial position within the discharge spigot with the pumping
volume remaining unchanged or bsing increased. The pumplng
volume will remain constant as long as the non-return valve at
the entering end of the device is closed. Wlth the pumping
volume being increased, concentrate will be withdrawn from the
container and transferred into the pumping space.
In a practical embodiment of this mod~fied device of the invent-
... . .
ion, the inner diameter of the pumpin~ space a~ounted to between
8 and l? Inm. The stroke length was adapted to be adjusted between
1 and 2 mm. The stroking frequency amounted to 50 cycles per
second~, but lt was possible to vary this ~requency bekween 10
and 100 cycles per second without the operation o~ the device
being impaired. The device was tested with liquids having a
viscosity ranging from 1 to lOO centipoise units. The non-
return valve located on the entry side was provided as passages
with slots arranged on a semicircle and adapted to be covered
by a small valve plate. It ~as found that no dripping of con-
centrate had to be expected with a length between 10 and 40 mm
of the discharge spigot replacing the exit valve and with an
inner dlameter o~ said spigot between 1 and 3 mm.
l~ithout the flexible body or bellows 15 being supported by the
corset-like arrangement,said bellows will be subJect to an
irregular formation o~ externally-curved portions, this pheno-
menon impairing the accuracy o~ the metering operation. In
contrast to this, the corset-like s~pporting means o~ the in-
vention makes it possible to maintain volumetric tolerances of
hardly measurable magnitude.
Figure 3 shows a modified embodiment of the component parts
dei'ining the pumping space. Mounted in a cylindrical houslng
40, the upper end of which is adapted to be connected to the
container for the concentrate, is an upper sleeve member 42
l~hich is provided with an outwardly projecting flange at its
upper end. A corresponding lower sleeve member 43 is provided
ill the lower end of housing 40 and rigidly attached to a cover
member having an outlet spigot 49. In the example sbown, it is
.ssumed that the lower sleeve member 43 is guided with clearance
in the lower end of housing ~0. Also the lower sleeve member 43
is provided with an outwardly projecting flange. ~etween the
lower portion of housing 40 and the two approximately aligned
spigot sections 42 and ~3 which are made of a rigid material
such as a plastic material there is provided an annular space 47.
Disposed in this annular space is a spreading or biasing spring
~8 the ends of which bear against the flanges of sleeve members
1~ and 4X, said spring tending to hold the t\~o sleeve members
in their spread-apart position shown in Figure 3. In the
embodiment shown the lower spigot is connected to an annular
armature 45 which is adapted to be actuated in such a manner
by the electromagnetic operating means (not shown) that the
lower spigot 43 can be raised until it bears against the upper
spigot 22 for the performance of a pumping stroke. The two
opposing encls o~ the two spigots are sealingly interconnected
by a bellows member 44 which essentially applies no ~orces to
the spigots. l~ith the two spigots 4? and 43 being brought lnto
their proximate position, the ~old 44 is practically closed
~ompletely.
In order to prevent air from being compressed in the annular
space 47 in synchronism with the pumping strokes, said annular
space is ventilated to the external atmosphere via slots or
drilled holes 50 which should be arranged at the minimum pos-
~ible Aistance from the final position attained during a pumping
stroke so as to provide a flow path o~ minimum length ~or the
air displaced as the volume o~ annular space 47 is varied.
Provided in the vicinity o~ the upper flange o~ spigot 42 is
the inlet valve (not shown) o~ the pumping chamber, it being
possible to provide an inlet valve which resembles the embodi-
ment described earlier. In Figure 3 the pumping motion of the
lower sleeve member 43 is indicated by the double~headed arrow
~. It would also be possible to provide an arrangement in
which the two sleeve members are adapted to move towards and
a~ay ~rom one another. The embodiment shown in Figure 3 a~ords
the advantage that no concentrate can enter the annular space
~7. The spigot 49 can be constructed in such a way that it is
not necessary to associate a non-return valve to the outlet.
It will be understood that such an arrangement which is operable
independently o~ the elastic restoring i'orce o~ a rubber bellows
is capable o~ metering almost paste-like media which are not
adapted to be me-tered by means of the normally available
restorlng force provitled by a shape~retaining elastic body.
In this case it will be necessary to provide the magnetic
i'orces in a suitable mnnner. The spring ~orce can then be
determined in an analogous manner.
. .
The metering de-~ice oi` the invention is also suitable for
i~luids other than syrups and the likeO Particularly in the
case of perishable fluids, the pump elements employed in the
single-use unit afford the advantage that it is possible
by suitable manufacturing methods to limit the useful life,
for e~ample of the diaphragm, with the result that illegal
re~illing of the contalner will cause rapid deterioration of
the diaphragm so as to render the device useless. This is
an effective method of preventing hygienic problems from
nrising.
