Method of pump operation, use of the method in HPLC, pump, pump system, and HPLC system

Patent metadata

Field	Value
Publication number	US-10767643-B2
Application number	US-201816027554-A
Country	US
Kind code	B2
Filing date	Jul 5, 2018
Priority date	Jul 7, 2017
Publication date	Sep 8, 2020
Grant date	Sep 8, 2020

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=S simple (1+COR(t)); wherein S is the pump speed, S simple 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 A cor and a time-dependent function f(t), i.e., COR(t)=A cor ·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.

First claim

What is claimed is:

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=S simple (1 +COR ( t ));

wherein S is the pump speed, S simple 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 A cor and a time dependent function f(t); the method further comprising:
calculating the corrective amplitude A cor based on a measure of the flow of the fluid and a measure of the pressure of the fluid.

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

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

4. 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 A cor 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.

5. 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 A cor 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 A cor .

6. 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 A cor 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 A cor .

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

8. 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.

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

10. 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.

11. 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.

12. 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.

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=S simple (1 +COR ( t ));

wherein S is the pump speed, S simple 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 A cor and a time dependent function f(t); and

b) calculate the corrective amplitude A cor based on a measure of the flow of the fluid and a measure of the pressure of the fluid.

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

15. The high pressure liquid chromatography system of claim 13 , wherein the corrective amplitude A cor 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.

16. 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.

Assignees

• Dionex Softron Gmbh

Inventors

• Strobl Christoph
• Haeckel Michael
• Seitz Stefan

Classifications

• G05D7/0676

  by action on flow sources (G05D7/0688, G05D7/0694 take precedence) · CPC title

• G01N2030/326

  pumps · CPC title

• F04B2205/04

  Pressure in the outlet chamber · CPC title

• F04B2205/09

  Flow through the pump · CPC title

• G01N30/36

  in high pressure liquid systems · CPC title