Method for controlling a first reference temperature in a device for compressing gas

Patent metadata

Field	Value
Publication number	US-12429044-B2
Application number	US-202218730107-A
Country	US
Kind code	B2
Filing date	Dec 14, 2022
Priority date	Jan 25, 2022
Publication date	Sep 30, 2025
Grant date	Sep 30, 2025

Abstract

A method for controlling a first reference temperature in a device ( 1 ) for compressing gas, the device ( 1 ) including an oil-injected element ( 2 ) for compressing the gas; an oil injection pipe network ( 6 ) for injecting oil into the oil-injected element ( 2 ), including: an apportioning means ( 8 ) for apportioning the oil into a first part and into a second part; an oil cooler ( 10 ) cooled by a fan ( 9 ), for cooling the first part; and a bypass ( 11 ) for diverting the second part past the oil cooler ( 10 ). An apportioning proportion of the first part is controlled to a required apportioning proportion, and subsequently a speed of the fan ( 9 ) is controlled to a required speed optionally on the basis of the apportioning proportion, wherein the apportioning proportion is controlled by a control unit ( 15 ) on the basis of a non-fuzzy logic algorithm.

First claim

The invention claimed is:

1. A method for controlling a first reference temperature in a device ( 1 ) for compressing gas to a first desired temperature value,
wherein the device ( 1 ) comprises:
an oil-injected element ( 2 ) for suctioning the gas at an inlet ( 3 ) of the device ( 1 ) and compressing this gas to an operating pressure at an outlet ( 4 ) of the oil-injected element ( 2 );
an oil injection pipe network ( 6 ) with a discharge ( 7 ) for injecting oil into the oil-injected element ( 2 ), comprising:
an apportioning means ( 8 ) for apportioning the oil into a first part and into a second part;
an oil cooler ( 10 ) cooled by a fan ( 9 ), for cooling the first part; and
a bypass ( 11 ) for diverting the second part past the oil cooler ( 10 ),

wherein the method comprises:
determining a required apportioning proportion of the first part for directing a second reference temperature in the device ( 1 ) to a second desired temperature value;
controlling an apportioning proportion of the first part to the required apportioning proportion;
determining a required speed of the fan ( 9 ) for directing the first reference temperature to the first desired temperature value, wherein, if the first reference temperature is the same as the second reference temperature, determining the required speed on the basis of the second desired temperature value and the apportioning proportion; and
controlling a speed of the fan ( 9 ) to the required speed,
wherein the apportioning proportion is controlled using a control unit ( 15 ) on the basis of a non-fuzzy logic algorithm with the following as input:
a first current value al for the second reference temperature; and
the second desired temperature value.

2. The method according to claim 1 , wherein the second desired temperature value is determined on the basis of a highest temperature value in a group of one or more temperature values.

3. The method according to claim 2 , wherein a first temperature value T 1 in the said group is representative of a value Tcond of the second reference temperature at which a temperature of the compressed gas at the outlet ( 4 ) is equal to
a first condensation temperature of the compressed gas at the outlet ( 4 ); or
the first condensation temperature plus a first safety margin.

4. The method according to claim 3 , wherein the first temperature value T 1 is limited according to a first temperature interval between a first minimum temperature limit value Tmin, 1 and a first maximum temperature limit value Tmax, 1 .

5. The method according to claim 2 , wherein a second temperature value T 2 in the said group is representative of a value of the second reference temperature at which a specific energy requirement of the device ( 1 ) is minimal.

6. The method according to claim 5 , wherein the second temperature value T 2 is determined on the basis of at least
a second current value α 2 representative of the operating pressure; and
a third current value α 3 representative of a temperature of the gas at the inlet ( 3 ).

7. The method according to claim 6 , wherein, in the case that the oil-injected element ( 2 ) is driven by a variable-speed motor, the second temperature value T 2 and/or the first speed value v 1 , respectively, is further determined on the basis of a tenth current value α 10 and eleventh current value α 11 , respectively, which are representative of a rotational speed of the variable-speed motor.

8. The method according to claim 5 , wherein the second temperature value T 2 is limited according to a second temperature interval between a second minimum temperature limit value Tmin, 2 and a second maximum temperature limit value Tmax, 2 .

9. The method according to claim 2 , wherein
the second reference temperature is controlled from an old temperature value to the second desired temperature value; and
to determine the second desired temperature value, the said highest temperature value is limited according to a third temperature interval between, on the one hand, the old temperature value minus a maximum temperature decrease value ΔTmax,down and, on the other hand, the old temperature value plus a maximum temperature increase value ΔTmax,up.

10. The method according to claim 9 , wherein the second reference temperature is controlled from the old temperature value to the second desired temperature value in a predefined time interval Δt, and that the maximum temperature decrease value ΔTmax,down and the maximum temperature increase value ΔTmax,up are positively dependent on a length of the predefined time interval Δt.

11. The method according to claim 2 , wherein the required apportioning proportion is determined according to a first ratio β 1 between the first current value α 1 and the second desired temperature value.

12. The method according to claim 11 , wherein the required apportioning proportion, between a minimum zero value and a maximum value of 100%, is dependent on the first ratio β 1 according to a first monotonically increasing function.

13. The method in accordance with claim 11 , wherein the required apportioning proportion
has a maximum value of 100% when the first current value α 1
is higher than the second desired temperature value or the second desired temperature value plus a second safety margin; or
is higher during a first period than the second desired temperature value or the second desired temperature value plus the second safety margin;
and
has otherwise a minimum zero value.

14. The method according to claim 1 , wherein the second reference temperature
is a temperature of the gas at the outlet ( 4 ) of the oil-injected element ( 2 ); or
is a temperature of the oil at the discharge ( 7 ) of the oil injection pipe network ( 6 ).

15. The method according to claim 1 , wherein the required speed is determined on the basis of a highest speed value in a set of one or more speed values.

16. The method according to claims 15 , wherein a first speed value v 1 in the said set is representative of a value for the speed of the fan ( 9 ) required to achieve the second desired temperature value for the second reference temperature.

17. The method according to claim 16 , wherein, when
a fourth current value α 4 for the second reference temperature is higher than a predefined minimum temperature; and
a fifth current value α 5 for the apportioning proportion is higher than a predefined minimum apportioning proportion and the fourth current value α 4 is higher than the second desired temperature value,
the first speed value v 1 is determined on the basis of at least
a sixth current value α 6 representative of the operating pressure; and
a seventh current value α 7 representative of a temperature of the gas at the inlet ( 3 ).

18. The method according to claim 17 , wherein, when
the fourth current value α 4 is higher than the second desired temperature value plus a first tolerance value; or
during a second period, the fourth current value α 4 is higher than the second desired temperature value plus the first tolerance value; or
the fourth current value α 4 is lower than the second desired temperature value minus a second tolerance value; or
during a third period, the fourth current value α 4 is lower than the second desired temperature value minus the second tolerance value,
the first speed value v 1 is further determined on the basis of at least
the fifth current value α 5 for the apportioning proportion; and
a second ratio β 2 between the fourth current value α 4 and the second desire

Assignees

• Atlas Copco Airpower Nv

Inventors

• Dauwe Bram Julien
• De Schamphelaere Pieter Guy Monique
• Lefevre Brice Hugo
• Bultinck Senne

Classifications

• F04B39/066 Primary

  Cooling by ventilation · CPC title

• F04C29/04

  Heating; Cooling (of machines or engines in general F01P); Heat insulation (heat insulation in general F16L59/00) · CPC title

• F04C29/042

  by injecting a fluid (injection of fluid for sealing, cooling or lubrication F04C29/0007) · CPC title

• F04B2205/11

  Outlet temperature · CPC title

• F04B2205/10

  Inlet temperature · CPC title