||Pumpvorrichtung zum Dosieren von Flüssigkeiten.
||Hewlett-Packard Co., Palo Alto, Calif., US
||Bente, H. Bryan, Half Moon Bay, CA. 94109, US;
Myerson, Joel, Berkeley, CA. 94702, US;
Herman, Alan C., Half Moon Bay, CA. 94019, US;
Shaw, Benjamin G., Palo Alto, CA. 94301, US;
Stefanski, Andrew, Menlo Park, CA. 94025, US
||Boehmert, A., Dipl.-Ing.; Hoormann, W., Dipl.-Ing. Dr.-Ing., 2800 Bremen; Goddar, H., Dipl.-Phys. Dr.rer.nat.; Liesegang, R., Dipl.-Ing. Dr.-Ing.; Münzhuber, R., Dipl.-Phys., 8000 München; Winkler, A., Dr.rer.nat., 2800 Bremen; Busch, T., Dipl.-Ing., Pat.-Anwälte, O-7010 Leipzig; Stahlberg, W.; Kuntze, W.; Kouker, L., Dr., 2800 Bremen; Nordemann, W., Prof. Dr.; Vinck, K., Dr.; Hertin, P., Prof. Dr.; Brocke, vom, K.; Pufendorf, von, L., 1000 Berlin; Huth, M., Rechtsanwälte, 2800 Bremen
||CH, DE, FR, GB, IT, LI, NL, SE
|Sprache des Dokument
|EP date of grant
|Veröffentlichungstag im Patentblatt
This invention relates to an apparatus for mixing and delivering
fluid as claimed in the first part of claim 1. In a known apparatus of this type
(DE-C-901 626) the common intake conduit contains at least one valve which is to
be shut or opened, respectively, in addition to the operation of valves arranged
each in one of said supply conduits in order to perform the desired mixing proportion.
No means are provided to independently change the displacement in each chamber,
which is, however, known in an apparatus for pumping a single fluid at a precise
The requirements of a mixing pump system in a liquid chromatograph
are very stringent. Liquid flow into its separation column must have a substantially
uniform flow rate and liquid pressure. Further, in gradient chromatography, the
composition of the liquid so supplied must be gradually altered over time. Separate
liquid constituents are mixed together in varying relative concentrations over
time by the mixing pump system.
There are basically two categories of liquid mixing pumps that have
previously been used for such an application. One category is known as a high pressure
mixing pump system, and the other category is known as a low pressure mixing pump
In the high pressure mixing pump system, as e.g. known from US-A-3
869 067, each liquid constituent, or component, to be mixed is connected from a
reservoir of that component to an input of its own liquid pump. That is, each component
is put under pressure by its own dedicated pump, and the outputs of each of the
component pumps are joined together to form the output of the mixing pump system
that is connected to the separation column of a liquid chromatograph, in that
particular application. The flow rate of each pump is adjusted to provide the
right proportions of the liquid components in its output, and to control the total
flow velocity in that output. A usual application requires the proportions of the
components to change over time, termed "gradient" flow, which requires the flow
rates of the individual pumps to be appropriately changed over time to accomplish
this. For example, if two components are being supplied in the mixing pump output
with the percentage of one component increasing over time and that of the other
component decreasing, the respective pumps for these components have their flow
rates respectively increased and decreased over time in order to alter the balance
of component concentrations without changing the total output flow rate.
A significant disadvantage of high pressure mixing systems is that
a separate pump is required for each solvent or other liquid component that is
being mixed. In some cases, more than two such components must be mixed. In the
liquid chromatograph supply application particularly, the pumps must be of high
precision and thus are very expensive. Typically, each such pump includes two
displacement chambers, or syringes, that are operated approximately l80° out of
phase so that one pump chamber is discharging fluid while the other is charging.
This category of high pressure system has a significant operating advantage, however,
in that the component concentration in the output flow can be smoothly varied over
time since each of the component pumps can have their flow rate independently
The second category of mixing pump systems is termed a low pressure
type. In this type, a single pump is utilized with each of the solvents, or other
liquid components, connected from their separate sources to the input of the pump.
Dual displacement chambers, or syringes, are generally used to make up this pump.
Each liquid component supply is connected to the intake of the pump through a
control valve. The pump is operated so that when a displacement chamber is being
charged, each liquid component control valve is turned on for a portion of the
charging part of the cycle. That is, in the usual case of a piston type displacement
chamber, the valve of one constituent supply is opened for a first part of the
intake stroke of the piston, it is then closed, and a valve of a second liquid
component supply is opened for a time, and so forth, for each of the components
that are to be mixed. While one displacement chamber is being charged with a mixture
of components in a particular proportion, the other displacement chamber is discharging
its previously mixed liquid. The two pistons of the two displacement chambers are
mechanically connected to operate essentially l80° out of phase with each other.
The result is a liquid output whose composition changes in a step function fashion;
that is, when the particular mixture in one chamber is completely discharged,
the next chamber begins to discharge a mixture which usually is different in its
percentage of liquid components. Thus, there is a sudden change in the proportion
of components of the mixture when the discharge of one pump chamber ends and the
An advantage of the low pressure category of mixing pump systems
is that only one pump with a pair of displacement chambers is required, in combination
with appropriate intake valving of the various liquid component supplies, thereby
minimizing the complexity and cost of a high precision pumping system. A disadvantage,
however, of this category of mixing pumps, is its limited output flow rate range.
The maximum flow rate is limited by the switching speed of the component liquid
intake valves. As the output flow rate increases, the speed of the pump has to
increase, which results in the intake stroke time being reduced. At some point,
the intake stroke time becomes too short for the inlet valves to switch with enough
control to provide the precise proportions of components desired during the short
The low pressure mixing systems also have a lower limitation of output
flow. As the flow rate of such a pumping system decreases, the time for the delivery
stroke becomes very long. Since the composition of the various liquid components
in the displacement chamber is not changed during each discharge stroke, the pump
system output composition has to remain the same for the duration of the delivery
of each discharge stroke. The slower the pump operates, the longer is the duration
of discharge of a particular fixed mixture. Since such a mixing pump system is
usually utilized where the output mixture is desired to have a gradual change
in relative concentrations of its components, there is some limit as to how long
this period of constant output mixture can be tolerated. Thus, this places a lower
limit on the flow rate available from the low pressure category of pumps.
Some improvements have been made in the operation of both categories
of pumps by paying attention to the mechanical drive interconnection between the
pistons of the two displacement chambers. Rather than operating exactly 180° out
of phase with the other, such linkages have been provided so that the common motive
source of the pump provides a slightly longer discharge time of each chamber than
its intake time. The reason for this is to smooth out the liquid flow rate by avoiding
any discontinuities when one displacement chamber ends its discharge stroke and
the other begins. In many applications, such as in the liquid chromatograph, a
flow of uniform velocity and pressure is quite important. But such improvements
have not addressed the more basic limitations of such pumping systems that are
The problem underlying the present invention is to provide an apparatus
according to the first part of claim 1, which is mechanically simple, and thus
of low cost, but which provides a liquid output that smoothly and accurately varies
the composition of the fluid output over a wide range of pump output flow rates,
and which may be adapted for a wide variety of specific applications and requirements.
This problem is accomplished by claim 1.
In the apparatus of the invention, briefly, a single pump of at least
two displacement chambers is provided wherein each chamber is separately driven
in a manner that is independent of the other. In a preferred form of the invention,
each displacement chamber includes a piston that is driven by a separate electrical
motor. The motors are in turn controlled by appropriate control electronics in
order to provide desired predetermined relative operation of the pistons. The fluid
components to be mixed are connected to the intakes of the displacement chambers
through electrically operated valves that are also controlled by the control electronics.
The outputs of the displacement chambers are connected together to form a common
pump output. The structure of the pumping system is similar to that of the low
pressure category of pumps discussed above, except that its driving pistons are
no longer connected to a common motor drive source but rather have been mechanically
uncoupled from each other so that they may be independently operated.
It has been discovered that independent control of the intake and
discharge portions of the piston cycle can lead to some very beneficial improvements
in the smoothing of the change (gradient) of the output liquid mixture. According
to one specific aspect of the present invention, the intake portion of the cycle
is made a fixed duration of time for any discharge flow rate over a wide range.
The fixed intake time allows the inlet valves to be operated in the same manner
independent of the output flow rate of the pumping system.
In one specific form of the fixed intake time feature of the present
invention, the piston stroke distance is made larger and its velocity is increased,
so the pump cycle time remains the same when the flow rate output is desired to
be increased. Existing mechanical linkages of the pistons do not allow varying
the piston stroke length, but an independent motor drive does. A significant added
advantage of this improved operation is that the duration of time during which
the output has an unchanging mixture also remains the same, no matter what the
output flow rate; that is, the duration of the steps in mixture of the liquid components
is held fixed in time as the pump flow rate is increased. This is not the case
with existing low pressure mixing pumps where the steps of constant mixture output
increase in duration as the flow rate decreases, making the output gradient depart
further from the desired continuous function.
In another specific form of the fixed intake time aspect of the present
invention, the stroke is held constant and the piston velocity profile is the same
on each intake stroke over the full range of output flow rates. In this case, the
discharge portion of the stroke is controlled, independent of the intake stroke,
to provide the desired output flow rate. The discharge portion of the cycle is
made to take more time than that of the fixed intake portion, as the flow decreases,
so there is a significant overlap wherein both displacement chambers are simultaneously
discharging fluid into their common output. This allows a gradual change in the
pump output from the mixture of one displacement chamber to that of the other.
This combines the best features of both the low pressure and high pressure types
of mixing pump systems. The time that the mixture in the pump output has to be
that of a single displacement chamber is the fixed time of the intake stroke; this
time does not increase as the output flow rate is decreased.
Additional objects, advantages and features of the various aspects
of the present invention will become apparent from the following description of
its preferred embodiment, which description should be taken in conjunction with
the accompanying drawings.
Brief Description of the Drawings
Description of the Preferred Embodiments
- Figure l illustrates a liquid chromatograph that utilizes the improved mixing
pump techniques of the present invention;
- Figure 2 shows the physical structure of the improved mixing pump of the present
- Figures 3 and 4 are curves that illustrate the operation of the mixing pump
of Figure 2, according to one specific embodiment thereof; and
- Figures 5 and 6 are curves which illustrate the operation of the mixing pump
of Figure 2, according with another specific embodiment thereof.
Referring initially to Figure l, a liquid chromatography system is
schematically illustrated for the purpose of showing one very specific application
of the mixing pump improvements of the present invention. A container ll of a liquid
solvent A is connected by a supply tube l3 to a mixing pump system l5. Similarly,
a second container l7 holds a different solvent B that is connected to the mixing
pump l5 through a conduit l9. In some applications, only two solvents A and B are
used. In other applications, however, additional solvents are utilized, an indefinite
additional number being illustrated by another container 2l of the Nth solvent
that communicates by a conduit 23 with the mixing pump l5.
The mixing pump l5 mixes the input solvents in a predetermined manner
to be explained hereinafter, and delivers the mixture under pressure in a conduit
25. For a liquid chromatograph instrument, it is important that the flow in the
output conduit 25 be of uniform velocity and pressure. That flow passes through
a sample injection valve 27, that introduces a small liquid sample therein that
is applied through a sample tube 29. The combined solvent with sample is then delivered
through a tube 3l to a separation column 33, a primary element of a standard chromatograph.
As is well known, the separation column includes beads that are coated with a
composition that retains the sample material from the flow in the conduit 3l.
A gradual change in the composition of the solvent liquid that is
applied to the column 33 liberates different constituents of the sample material
from the beads at different times. It is the mixing pump l5 that causes the composition
of the solvent flow through the separation column 33 to change over time in a precise,
predetermined way. The solvent with sample material is then passed through a detector
35. The presence of quantities of sample material constituents at different times
tells the analyst the composition of the sample material originally injected into
the tube 29. The liquid is then discharged from the detector into a container
37. That liquid can be considered as waste, and discarded, or can be collected
in separate containers at the times that the different sample constitutents are
being discharged from the column 33.
Referring to Figure 2, the mixing pump l5, utilizing the various
aspects of the present invention is described. At the heart of the pumping unit
are two displacement chambers 39 and 4l. Each displacement chamber contains, in
this embodiment, cylinders 40 and 42, and pistons 43 and 45 respectively. The pistons
are operated to control the volumes of their respective chambers. The two displacement
chambers are connected in parallel. That is, the discharge from each of the chambers
39 and 4l passes through their respective outlet conduits 47 and 49, through their
respective check valves 5l and 53, and into the single liquid output conduit 25.
Similarly, liquid inputs in the conduits l3, l9 and 23 are applied through their
respective valves 57, 59 and 6l, to a common intake conduit 63. The liquid openings
47 and 49 to the two displacement chambers 39 and 4l, respectively, receive liquid
from the common input conduit 63 through their respective input check valves 65
and 67. Alternatively, check valves 5l, 53, 65 and 67 could be replaced by actively
The valves 57, 59 and 6l may be individual valves that are electrically
controlled by signals in control lines 7l, 73 and 75, respectively. Alternatively,
a single mechanical proportioning valve may be substituted for the individual valves
57, 59 and 6l. In either case, the purpose of the input valves is to connect one
liquid solvent at a time to a displacement chamber that is being charged. For
example, withdrawal of the piston 43 in the chamber 39 will cause fluid to flow
through the check valve 65 into the chamber 59, the fluid so flowing being chosen
by connecting one of the conduits l3, l9 or 23 at a time into the common input
Instead of driving the pistons 43 and 45 from a fixed mechanical
drive and a single motor, as is the predominant structure of existing mixing pumps,
a separate electric motor 77 is provided for driving the piston 43, and another
separate motor 79 is provided for driving the piston 45. Each of these motors may
be chosen from among those readily available, such as a stepper motor or a direct
current motor with a servo feedback control added. In any case, each of the motors
is chosen to be of a type that can accurately and predictably position its respective
piston within its respective displacement chamber. Control signals for the motors
are provided in circuits 8l and 83, respectively. Suitable control electronics
85 are designed to provide the appropriate signals in the lines 7l, 73, 75, 8l
and 83 in order to cooperatively move the pistons and open the intake valves in
order to operate the pump system of Figure 2 in a particular, predetermined manner.
Two such particular operable configurations for the pump of Figure
2 are illustrated in Figures 3 through 6. Figures 3 and 4 illustrate an operable
configuration where the displacement of the pistons 43 and 45 is altered when it
is desired to change the flow rate in the output 25 of the pump. The piston stroke
of existing pumps cannot be changed because they are driven from a common motor
source through an interlocked mechanical system.
A second exemplary operable configuration for the improved mixing
pumping system of Figure 2 is illustrated in Figures 5 and 6. In this second example,
the piston stroke lengths remain constant and the flow rate in the output 25 is
adjusted by varying the velocity of the piston during the discharge portion of
In both of these examples described below, the intake or charge time
interval is constant for each of the displacement chambers, no matter what output
flow is desired from the pump. Therefore, the same amount of time is provided for
operation of the intake valves 57, 59 and 6l in order to assure accurately metered
proportions of the different liquid components of the output mixture desired.
Furthermore, as will better be seen from the following description of these two
specific operable examples, the fixed chamber intake time allows a smoother gradient
in the mixture in the output 25. These are significant improvements over the existing
low pressure type mixing pump system. Subject to some constraints, the intake
and discharge strokes may be optimized independently of each other since the pistons
43 and 45 are not mechanically locked to travel together.
Referring initially to Figure 3, the first specific example will
be described. Figure 3(A) shows the flow into and out of each of the displacement
chambers 39 and 4l. Shown in a solid curve 9l is the flow through the conduit 47
of the chamber 39. Shown in a dashed curve 93 is, similarly, the flow in conduit
49 to and from the displacement chamber 4l. In this example, it can be seen that
the motors 77 and 79 are driving their respective pistons 43 and 45 essentially
l80° out of phase with each other; that is, as one is filling its respective chamber,
the other is discharging liquid from its chamber. A portion of each curve 9l and
93 above the middle "0" line shows a flow out of the respective displacement chamber,
while that below the "0" line shows fluid flow into the respective chamber.
It will be noted from curve 9l of Figure 3(A) that the valves 57
and 59 of Figure 2 are operated so that the liquid solvent or component A from
the container ll is drawn into the chamber 39 for a certain portion of the intake
cycle that is illustrated between times tl and t2. During the remainder of the
time the liquid component B is drawn into the chamber from the supply l7. In the
examples shown in Figures 3-6, only two components A and B are assumed to be utilized,
for simplicity in explanation, but it will be understood that additional liquid
components can be introduced in the same manner, if desired.
Referring to Figure 3(B), the relative proportions of the components
A and B in the flow from the output 25 are illustrated. A dashed line 95 shows
an ideal output gradient; that is, the ideally linear gradual change from, in this
example, a low percentage of component A in the output mixture at the beginning,
to a higher percentage of component A at a later time. A step function curve 97,
however, reflects the actual variation in the composition of a mixture in the output
25. It is a step function since the composition of the pumps output can change
only at times tl, t2, etc. The mixture of components A and B that are drawn into
the chamber 9l during the time period tl-t2 is then discharged in the next time
period t2-t3, that mixture being indicated at 99 on Figure 3(B). Similarly, the
mixture of components A and B drawn into the chamber 4l during the time period
t2-t3 is that discharged from the output 25 during the next half-cycle, between
times t3-t4, and is shown on Figure 3(B) to have a percentage of component A indicated
A maximum intake flow indicated at l03 of Figure 3(A), and a maximum
discharge flow indicated at l05, is determined in this specific example by the
displacement of the pistons in the respective chambers. The time interval for intake
and discharge remains a predetermined fixed value. If it is desired to change
that flow, as illustrated in Figure 4, the piston stroke is adjusted accordingly.
With reference to Figure 4(A), for example, one-half the output flow rate is provided
by shortening the piston stroke length by one-half. An output flow rate indicated
at l07 is chosen, for this example, to be one-half of that indicated at l05 in
Figure 3(A). Of course, the intake stroke is also one-half of the previous example,
a maximum intake flow rate indicated at l09. Figure 4(A) is otherwise similar to
It is extremely interesting to compare the output mixture gradient
97′ of Figure 4(B) with the gradient 97 of Figure 3(B). They are identical
since the intake and discharge times are, respectively, the same as that in the
Figure 3 example. The flat portion of the curve 97′ of Figure 4(B) remains
the same as that of the curve 97 of Figure 3(B). The output gradient does not depart
any further from the ideal desired straight line 95 (95′) when the output
pump flow is decreased, contrary to the case in existing low pressure type mixing
The second specific operational example for the mixing pump l5 is
described with respect to Figures 5 and 6, each of which is a curve showing information
similar to that previously described with respect to Figures 3 and 4, but for fixed
stroke, fixed intake time operating conditions. Referring initially to Figure 5(A),
the flow into and out of chamber 39 is indicated by a curve lll in solid outline.
Similarly, the flow into and out of the chamber 4l is shown by a curve ll3 in dotted
outline. In Figure 5(B), a desired linear gradient change in the mixture at the
output 25 is shown by a dashed line ll5, the actual mixture as a function of time,
for this specific embodiment, being shown as a solid line ll7.
Between times tl and t2, the pump of Figure 2 is operating according
to the specific example of Figure 5 with its chamber 4l being charged with liquid
constituents A and B in time sequence, as shown by curve ll3 of Figure 5(A), while
the chamber 39 is discharging at a maximum rate ll9, as indicated by the curve
lll. During a time interval t2-t3, both of the chambers 39 and 4l are discharging,
the one that has just been filled discharging at a gradually increasing flow rate
while the chamber that had been discharging at a maximum rate during the interval
tl-t2 now discharging at a gradually decreasing flow rate. The total flow from
the two chambers, in this example, is maintained constant so that the flow rate
at the output 25 of the pump is constant. The individual flows from the chambers
need not necessarily be linearly increasing or decreasing, but the sum of the discharges
from the two should be constant over time. This mixing makes the output composition
gradually change from a level l20 to l2l in the interval t2-t3.
In the next interval of time t3-t4, the chamber 39 is being charged
with a somewhat different mixture of liquid from the solvents A and B, the proportion
of A being greater than during the chamber 4l fill of times tl-t2. At that same
time, the chamber 4l, as indicated by the curve ll3, is discharging fluid at the
maximum rate ll9.
During the next interval of time t4-t5, both chambers are again simultaneously
discharging through the common pump output 25, the one that has just been filled
linearly increasing its flow, and the other decreasing its flow. The interval between
time tl and t5 constitutes a complete, single cycle of the pump's operation, which
is then repeated.
The changing composition of the mixture at the output 25 is shown
over the same time period in Figure 5(B). The mixture (percentage of component
A) being discharged during the time period t3-t4, indicated at l2l, is the mixture
that was drawn into the chamber 4l during the time period tl-t2. Similarly, the
mixture at times t5-t6, indicated at l23, is that drawn into the chamber 39 during
the previous fill interval t3-t4.
Referring to Figure 6, the same basic operational example as Figure
5 is given, except that the flow rate is reduced to one-half, while the desired
gradient is the same. This reduced flow rate is indicated at l25 of Figure 6. The
reduced flow rate is accomplished by reducing the velocity of the piston during
its discharge portion of its stroke, and this increases the time for discharge.
The velocity and duration of the intake portion remain the same, as discussed previously.
This means that the flat portions of the curve ll7′of Figure 6(B) remain
of the same duration; that is, it is only during this fixed duration of the intake
stroke of one chamber that liquid of unchanging composition is being discharged
to the output 25 from the other chamber. This is an improvement over existing low
pressure mixing pumps that increase the flat portions of their curves corresponding
to curve ll7′ in the same proportion as the total pump cycle time.
There are many other variations of these two specific modes of operating
the pump of Figure 2 that are obviously available. For example, the velocity profile
of piston movement during the intake stroke can be modified, such as stopping it
during the portion of the stroke when the valves 57 and 59 are operated to switch
from one liquid component to the other. This can provide greater precision in solvent
proportioning. This is another advantage of uncoupling the two pistons of the displacement
chambers, since without it, such a feature could not be implemented. Prior devices,
with a common piston driving mechanism, would also stop the discharge flow for
the period that the intake flow is stopped.
Another advantage of the separate piston motor drive is that the
velocity profile of the piston during its delivery stroke can be modified to compensate
for the compressibility of the liquid. This can be done without having to affect
in any way the intake stroke.
The concepts of the present invention have been described as implemented
in a liquid pump especially adapted for a liquid chromatograph. Of course, it will
be understood, that the concepts have applicability in liquid pumps for other applications,
particularly those with high precision requirements of liquid flow and mixture
control. Also, the configuration of the pump described is also useful for mixing
and pumping air and other gases. Further, it is useful for other substances that
can be handled like fluids, such as slurries.
Although the various aspects of the present invention have been described
with respect to preferred embodiments thereof, it will be understood that the invention
is to be protected within the full scope of the appended claims.
- Vorrichtung zum Mischen und Abgeben von Fluid mit einer Pumpvorrichtung mit
mindestens zwei Verdränger-Kammern (39,41), die je einen Fluideinlaß und einen
unabhängigen Quellen (11,17,21) für mindestens zwei Fluide, wobei jede Quelle eine
von einer individuell sperrbaren Speiseleitung (13,19,23) gebildeten Fluidauslaß
einer Einlaßverbindungsvorrichtung (63,65,67) zum Verbinden sämtlicher Fluidquellen
(11,17) gemeinsam mit den Fluideinlässen jeder Kammer (39,41) zum Schaffen einer
steuerbaren Aufteilung der Fluide aus den Quellen auf die Einlässe, wobei die
Einlaßverbindungsvorrichtung Einlaßventile (65,67) zum Verbinden der Kammern (39,41)
mit den Speiseleitungen (13,19,23) und Auslaßventile (51,53) zum Verbinden der
Auslässe der Kammern miteinander zum Bilden eines einzigen Fluidauslasses (25)
aufweist, dadurch gekennzeichnet,
daß die Verbindungsvorrichtung (63,65,67) eine gemeinsame Einlaßleitung (63) aufweist,
welche die sperrbaren Speiseleitungen (13, 19, 23) permanent mit den Kammern (39,41)
daß eine Regelvorrichtung (77,79,85) zur gleichzeitigen Regelung der Einlaßventile
(65,67) und der Volumenveränderung jeder Kammer (39,41) vorgesehen ist, derart,
daß jeweils ein einziges Fluid zu einer gerade zu befüllenden Kammer gespeist
- Vorrichtung nach Anspruch 1, dadurch gekennzeichnet,
daß die Regelvorrichtung
(77,79,85) Mittel (77,79) zum Verändern des Fluidstromes durch den Auslaß jeder
Kammer (39,41) unabhängig vom Fluidstrom durch die gemeinsame Einlaßleitung (63)
der Kammern aufweist, so daß die Charakteristika des Fluideinlasses und -auslasses
unabhängig für jede Kammer über einen gegebenen Durchfluß optimiert werden können.
- Vorrichtung nach Anspruch 1 oder 2, dadurch gekennzeichnet,
(57,59,61) in den Speiseleitungen (13, 19, 23) angeordnet sind, welche zum Öffnen
oder Blockieren des Fluidstromes durch die Speiseleitungen mittels der Regelvorrichtung
(77,79,85) gesteuert sind.
- Vorrichtung nach Anspruch 3, dadurch gekennzeichnet,
daß die Regelvorrichtung
(77,79,85) vorgewählte Zeitdauern des Fluideinlasses während jedes Arbeitszyklus
für jede Kammer (39,41) aufrechterhält.
- Vorrichtung nach einem der vorangehenden Ansprüche, dadurch gekennzeichnet,
daß die Regelvorrichtung (77,79,85) die Strömungsgeschwindigkeit des aus dem Kammerauslaß
abgegebenen Fluids einstellt, wodurch ein Einlaßzyklusanteil zum Mischen der von
den Quellen abgegebenen Fluide (11,17,21) nach dem Einlaß in jede Kammer optimiert
und ein Auslaßzyklusanteil für einen gewünschten Fluidauslaß unabhängig eingestellt
- Vorrichtung nach Anspruch 4 oder 5, dadurch gekennzeichnet,
daß die Regelvorrichtung
(77,79,85) zusätzlich Mittel zum Veranlassen der gleichzeitigen Fluidabgabe aus
den Auslässen der Kammern (39,41) durch den einzigen Fluidauslaß (25) aufweist.
- Vorrichtung nach einem der Ansprüche 4 bis 6, dadurch gekennzeichnet,
daß die Regelvorrichtung (77,79,85) zusätzlich Mittel zum graduellen Vergrößern
des Fluidauslasses aus der einen Kammer (39,41) und gleichzeitigem graduellen
Verringern des Fluidauslasses aus der anderen Kammer (41,39) während eines Zeitabschnittes
mit gleichzeitiger Fluidabgabe aus den Kammern aufweist, wobei die Abgabe aus
jeder Kammer zusätzlich auf ein Maximum und im wesentlichen konstant während des
festgesetzten Einlaßzeitabschnittes der anderen Kammer eingestellt wird.
- Vorrichtung nach Anspruch 5, dadurch gekennzeichnet,
daß die Regelvorrichtung
(77,79,85) ein maximales Verdrängungsvolumen der mindestens zwei Kammern (39,41)
- Anwendung einer Vorrichtung nach einem der vorangehenden Ansprüche in einem
chromatographischen System für Flüssigkeiten, dadurch gekennzeichnet,
daß ein Probeninjektor (27) in dem Pfad eines einzigen Flüssigkeitsauslasses einer
Pumpenvorrichtung angeordnet ist,
eine chromatographische Säule (33) den einzigen Auslaß der Pumpenvorrichtung nach
dem Passieren durch den Probeninjektor aufnimmt und
ein Detektor (35) am Auslaß der Säule angeordnet ist.
- Apparatus for mixing and delivering fluid, comprising: pumping means having
at least two displacement chambers (39,41), each chamber having a fluid intake
and a fluid output,
independent sources (11,17,21) of at least two fluids, each said source having
a fluid outlet formed by an individually blockable supply conduit (13,19,23),
intake connecting means (63,65,67) for connecting each of the fluid sources (11,17,21)
together to the fluid intakes of each of said chambers (39,41) for providing a
controllable proportion of said fluids from said sources to said intakes, said
intake connecting means including intake valve means (65,67) for connecting said
chambers (39,41) to said supply conduits (13,19,23) and output valve means (51,53)
for connecting the outputs of the chambers together for forming a single fluid
characterized in that said intake connecting means (63,65,67) include a
common intake conduit (63), which connects said blockable supply conduits (13,19,23)
permanently to said chambers (39,41), and in that
control means (77,79,85) are provided for concurrent control of said intake valve
means (65,67) and for the displacement in each of said chambers (39,41), such
that a single fluid at a time is supplied to a displacement chamber that is charged.
- Apparatus according to claim 1,
characterized in that said control means (77,79,85) include means (77,79)
for changing the fluid flow through the output of each of said displacement chambers
(39,41) independently of the fluid flow through the common intake conduit (63)
of said chambers, whereby the characteristics of fluid intake and discharge can
be independently optimized for each displacement chamber for a given flow rate.
- Apparatus according to claim 1 or 2,
characterized in that valves (57,59,61) are arranged in said supply conduits
(13,19,23), which are controlled to open or block fluid flow through said supply
conduits by said control means (77,79,85).
- Apparatus according to claim 3,
characterized in that said control means (77,79,85) maintain preselected
time period of fluid intake during each cycle of operation of each of said two
- Apparatus according to one of the preceding claims,
characterized in that said control means (77,79,85) adjust the flow rate
of fluid discharged from the chamber's output, whereby an intake cycle portion
can be optimized for mixing the source fluids (11,17,21) upon intake to each chamber
and an output cycle portion thereof can be independently set for a desired fluid
- Apparatus according to claim 4 or 5,
characterized in that said control means (77,79,85) additionally include
means for causing said chambers (39,41) to simultaneously discharge fluid from
their outputs through said single fluid output (25).
- Apparatus according to one of claims 4 to 6,
characterized in that said control means (77,79,85) additionally include
means for causing the fluid output of one chamber (39,41) to gradually increase
while causing the fluid output of the other chamber (41,39) to gradually decrease
during a time period of simultaneous fluid discharge from the chambers, the discharge
of each chamber additionally being caused to be a maximum and substantially constant
during the fixed intake time period of the other chamber.
- Apparatus according to claim 5,
characterized in that said control means (77,79,85) sets a maximum volume
of displacement of said at least two chambers (39,41).
- Use of an apparatus according to one of the preceding claims in a liquid chromatography
characterized in that
a sample injector (27) is positioned in the path of a single pumping means liquid
a chromatograph column (33) receives the single pumping means output after passing
through said sample injector, and
a detector (35) is positioned at the output of said column.
- Dispositif pour mélanger et débiter un fluide, comprenant :
- un moyen de pompage comportant au moins deux chambres de refoulement (39, 41),
chaque chambre comportant une entrée de fluide et une sortie de fluide,
- des sources indépendantes (11, 17, 21) d'au moins deux fluides, chacune desdites
sources comportant une sortie de fluide formée par un conduit de distribution
(13, 19, 23) pouvant être fermé individuellement,
- des moyens de liaison d'entrée (63, 65, 67) pour relier chacune des sources
de fluides (11, 17, 21) ensemble avec les entrées de fluides de chacune desdites
chambres (39, 41) de manière à transmettre une proportion contrôlable desdits
fluides desdites sources auxdites entrées, lesdits moyens de liaison d'entrée
comprenant des moyens formant soupapes d'admission (65, 67) pour relier lesdites
chambres (39, 41) auxdits conduits de distribution (13, 19, 23) et des moyens
formant soupapes de sortie (51, 53) pour relier les sorties des chambres ensemble
afin de former une seule sortie de fluide (25),
- caractérisé en ce que lesdits moyens de liaison d'entrée (63, 65, 67) comprennent
un conduit commun d'entrée (63), qui relie lesdits conduits de distribution (13,
19, 23) pouvant être fermés en permanence avec lesdites chambres (39, 41),
- et en ce qu'il est prévu des moyens de commande (77, 79, 85) pour commander
concurremment des moyens formant soupapes d'admission (65, 67) et le refoulement
dans chacune desdites chambres (39, 41) de telle sorte qu'un seul fluide à la
fois soit fourni à une chambre de refoulement qui est chargée.
- Dispositif selon la revendication 1, caractérisé en ce que lesdits moyens de
commande (77, 79, 85) comprennent des moyens (77, 79) pour modifier l'écoulement
de fluide passant par la sortie de chacune desdites chambres de refoulement (39,
41) indépendamment de l'écoulement de fluide passant dans le conduit commun d'entrée
(63) desdites chambres, de telle sorte que les caractéristiques d'admission et
de décharge de fluide puissent être optimisées indépendamment pour chaque chambre
de refoulement et pour un débit donné.
- Dispositif selon une des revendications 1 ou 2, caractérisé en ce que des soupapes
(57, 59, 61) sont disposées dans lesdits conduits de distribution (13, 19, 23)
qui sont commandés pour laisser passer ou arrêter l'écoulement de fluide dans lesdits
conduits de distribution par lesdits moyens de commande (77, 79, 85).
- Dispositif selon la revendication 3, caractérisé en ce que lesdits moyens de
commande (77, 79, 85) maintiennent une période de temps présélectionnée d'admission
de fluide pendant chaque cycle de fonctionnement de chacune des deux chambres précitées
- Dispositif selon une des revendications précédentes, caractérisé en ce que
lesdits moyens de commande (77, 79, 85) règlent le débit de fluide déchargé de
la sortie de chambre de telle sorte qu'une partie de cycle d'admission puisse être
optimisée pour un mélange des fluides de sources (11, 17, 21) lors de l'admission
dans chaque chambre et une partie de cycle de sortie puisse être indépendamment
réglée pour une sortie désirée de fluide.
- Dispositif selon la revendication 4 ou 5, caractérisé en ce que lesdits moyens
de commande (77, 79, 85) comprennent additionnellement des moyens pour faire en
sorte que lesdites chambres (39, 41) déchargent simultanément du fluide à leurs
sorties par l'intermédiaire de ladite unique sortie de fluide (25).
- Dispositif selon une des revendications 4 à 6, caractérisé en ce que lesdits
moyens de commande (77, 79, 85) comprennent additionnellement des moyens pour
faire en sorte que le fluide sortant d'une chambre (39, 41) augmente graduellement
tout en faisant en sorte que le fluide sortant de l'autre chambre (41, 39) diminue
graduellement pendant une période de temps où du fluide est simultanément déchargé
des chambres, la décharge de chaque chambre étant portée additionnellement à un
maximum et étant sensiblement constante pendant la période fixée d'admission de
- Dispositif selon la revendication 5, caractérisé en ce que lesdits moyens de
commande (77, 79, 85) établissent un volume maximal de refoulement pour lesdites
deux chambres au moins prévues (39, 41).
- Utilisation d'un dispositif selon une des revendications précédentes dans un
système de chromatographie liquide, caractérisée en ce que :
- un injecteur d'échantillon (27) est disposé dans la voie suivie par un seul
écoulement de liquide sortant du moyen de pompage,
- une colonne chromatographique (33) reçoit l'unique écoulement sortant du moyen
de pompage après qu'il a traversé ledit injecteur d'échantillon, et
- un détecteur (35) est disposé à la sortie de ladite colonne.
Patent Zeichnungen (PDF)