# US 10,767,643 B2 · Method of pump operation, use of the method in HPLC, pump, pump system, and HPLC system

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- Number: US 10,767,643 B2
- Document ID: US10767643B2
- Status: Granted
- Kind: B2
- Application number: 16/027,554
- Filed: 2018-07-05
- Published: 2019-01-10
- Granted: 2020-09-08
- Earliest claimed: 2017-07-07
- Assignees: Dionex Softron GmbH
- Applicants: Dionex Softron GmbH
- Inventors: Christoph Strobl; Michael Haeckel; Stefan Seitz
- Web page: https://patentgrep.com/patent/US10767643B2

## CPC

- F04B 49/20: by changing the driving speed
- F04B 11/0058: {with piston speed control}
- F04B 49/065: {and making use of computers}
- G01N 30/32: of pressure or speed (G01N30/36 takes precedence)
- G01N 30/36: in high pressure liquid systems
- G05D 7/0676: {by action on flow sources (G05D7/0688, G05D7/0694 take precedence)}
- F04B 2205/04: Pressure in the outlet chamber
- F04B 2205/09: Flow through the pump
- F04B 2207/042: of pressure
- G01N 2030/326: {pumps}
- F04B: POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS (machines for liquids, or pumps, of rotary-piston or oscillating-piston type F04C; non-positive-displacement pumps F04D; pumping of fluid by direct contact of another fluid or by using inertia of fluid to be pumped F04F)
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)
- G05D: SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES

## Abstract

The present invention relates to a method of operating a pump generating a flow of a fluid with a pressure, the method comprising operating the pump with a pump speed S satisfying the equation S=Ssimple(1+COR(t)); wherein S is the pump speed, Ssimple is the pump speed disregarding any compression and/or expansion of the fluid, t is a time, and COR(t) is a time dependent correction function; wherein the time dependent correction function COR(t) is a product of a corrective amplitude Acor and a time-dependent function f(t), i.e., COR(t)=Acor·ƒ(t); and wherein the corrective amplitude Acor is set based on a measure for the flow and a measure for the pressure. The present invention also relates to a corresponding use, a pump, a pump system and an HPLC system.

## Claims

### Claim 1

A method of operating a pump generating a flow of a fluid with a pressure, the method comprising:
operating the pump with a pump speed S satisfying the equation
S=Ssimple(1+COR(t));
wherein S is the pump speed, Ssimple is the pump speed without correcting for a compression or an expansion of the fluid, t is a time, and COR(t) is a time dependent correction function;
wherein the time dependent correction function COR(t) comprises a product of a corrective amplitude Acor and a time dependent function f(t); the method further comprising:
calculating the corrective amplitude Acor based on a measure of the flow of the fluid and a measure of the pressure of the fluid.

### Claim 2 (depends on 1)

The method of claim 1, wherein the calculating the corrective amplitude Acor is based on a quotient of the measure of the pressure and the measure of the flow.

### Claim 3 (depends on 1)

The method of claim 1, wherein the corrective amplitude Acor is proportional to the measure of the pressure and is inversely proportional to the measure of the flow.

### Claim 4 (depends on 1)

The method of claim 1 further comprising:
moving a piston in a working head during a pre-compression phase where the pressure reaches a system pressure,
wherein the corrective amplitude Acor is an equation comprising:
A
cor
=
γ
·
p
F
where γ is a constant, p is the measure of the pressure of the fluid is at an end of the pre-compression phase, and F is the measure of the flow of the fluid.

### Claim 5 (depends on 4)

The method claim 4 further comprising:
flowing the fluid at a test flow and at a test pressure, wherein the test flow ranges from 1 μl/min to 10000 μl/min and the test pressure ranges from 50 to 1500 bar;
determining the corrective amplitude Acor that minimizes flow error based on the test flow and the test pressure;
determining the constant γ based on the test flow, the test pressure and the corrective amplitude Acor.

### Claim 6 (depends on 4)

The method claim 4 further comprising:
flowing the fluid at a test flow and at a test pressure, wherein the test flow ranges from 10 μl/min to 1200 μl/min and the test pressure ranges from 50 to 700 bar;
determining the corrective amplitude Acor that minimizes flow error based on the test flow and the test pressure;
determining the constant γ based on the test flow, the test pressure and the corrective amplitude Acor.

### Claim 7 (depends on 1)

The method of claim 1, wherein the measure of the pressure is based on a current for driving a motor of the pump.

### Claim 8 (depends on 1)

The method of claim 1, wherein the measure of the pressure is based on a compressibility of the fluid and a compression of the fluid.

### Claim 9 (depends on 1)

The method of claim 1, wherein the measure of the pressure is based on a strain of a structure subjected to the pressure.

### Claim 10 (depends on 4)

The method of claim 4 further comprises:
receiving the constant at the pump for the time dependent correction function COR(t) from an external unit.

### Claim 11 (depends on 4)

The method of claim 4 further comprises:
performing a calibration run with the external unit to obtain the constant; and
sending the constant from the external unit to the pump.

### Claim 12 (depends on 1)

The method of claim 1, in which the time dependent function f(t) is an equation comprising:
f
⁡
(
t
)
=
exp
⁡
(
-
t
τ
)
at least for t≤τ, wherein τ is a time constant.

### Claim 13

A high pressure liquid chromatography system comprising:
a pump configured to generate a flow of a fluid with a pressure, the pump comprising a controller configured to
a) operate the pump with a pump speed S satisfying the equation
S=Ssimple(1+COR(t));
wherein S is the pump speed, Ssimple is the pump speed without correcting for a compression or an expansion of the fluid, t is a time, and COR(t) is a time dependent correction function,
wherein the time dependent correction function COR(t) comprises a product of a corrective amplitude Acor and a time dependent function f(t); and
b) calculate the corrective amplitude Acor based on a measure of the flow of the fluid and a measure of the pressure of the fluid.

### Claim 14 (depends on 13)

The high pressure liquid chromatography system of claim 13, wherein the corrective amplitude Acor is based on a quotient of the measure of the pressure and the measure of the flow measurement.

### Claim 15 (depends on 13)

The high pressure liquid chromatography system of claim 13, wherein the corrective amplitude Acor is an equation comprising:
A
cor
=
γ
·
p
F
where γ is a constant, p is the measure of the pressure of the fluid is at an end of the pre-compression phase, and F is the measure of the flow of the fluid.

### Claim 16 (depends on 13)

The high pressure liquid chromatography system of claim 13, in which the time dependent function f(t) is an equation comprising:
f
⁡
(
t
)
=
exp
⁡
(
-
t
τ
)
at least for t≤τ, wherein τ is a time constant.