US20140290923A1

US20140290923A1 - Cooling system

Info

Publication number: US20140290923A1
Application number: US13/854,279
Authority: US
Inventors: Joseph M. Huelsmann; Neil A. Terry; Kevin A. Sheets; Albert Yuen-Chang Lee
Original assignee: Caterpillar Inc
Current assignee: Caterpillar Inc
Priority date: 2013-04-01
Filing date: 2013-04-01
Publication date: 2014-10-02

Abstract

A cooling system is provided. The cooling system includes a first heat exchanger and a second heat exchanger. The first heat exchanger has a first chamber and a second chamber. A plurality of tubes is provided in the first heat exchanger such that the tubes are in fluid communication with the first chamber and the second chamber. The tubes are arranged in a plurality of rows. A baffle is located in the second chamber. The baffle divides the second chamber into a first region and a second region. The first region of the second chamber is in fluid communication with at least one row of tubes. Further, an outlet is provided in fluid communication with the first region. The second heat exchanger includes an inlet in communication with the outlet of the first region.

Description

TECHNICAL FIELD

The present disclosure relates to a cooling system, and more particularly to a system and method for cooling a working fluid in a hydraulic system.

BACKGROUND

An engine is usually equipped with a radiator for cooling the engine using an appropriate coolant. The coolant from the radiator may also be used for a secondary application, such as, for example, cooling an oil used in a hydraulic circuit. In current systems, a hydraulic oil cooler is prone to plugging, is inaccessible for cleaning, and prevents access to clean the radiator. Hence, the hydraulic oil cooler needs to be relocated from the bottom of the cooling package to an area that can be cleaned easily. One possible solution includes moving the hydraulic oil cooler to a coolant circuit associated with a radiator. However, the temperature of the coolant associated with the radiator is relatively higher than that required by the hydraulic system installed on the machine.
U.S. Pat. No. 5,067,561 relates to a radiator apparatus. The apparatus includes an oil cooler located within the radiator tank. The oil cooler includes a plurality of pairs of tube plates wherein each pair defines tube. The coolant from the radiator tube is used to exchange the heat from the oil in the oil cooler.

SUMMARY OF THE DISCLOSURE

In one aspect of the present disclosure, a cooling system is provided. The cooling system includes a first heat exchanger and a second heat exchanger. The first heat exchanger has a first chamber and a second chamber. A plurality of tubes is provided in the first heat exchanger such that the tubes are in fluid communication with the first chamber and the second chamber. The tubes are arranged in a plurality of rows. A baffle is located in the second chamber. The baffle divides the second chamber into a first region and a second region. The first region of the second chamber is in fluid communication with at least one row of tubes. Further, an outlet is provided in fluid communication with the first region. The second heat exchanger includes an inlet in communication with the outlet of the first region.
In another aspect, a method for cooling a working fluid in a hydraulic system is provided. The method receives a coolant in a first chamber of a first heat exchanger. The method introduces the coolant into a plurality of tubes, the tubes being arranged in a plurality of rows. The method directs the coolant through the plurality of tubes towards a second chamber of the first heat exchanger. The method provides a baffle in the second chamber. The baffle is configured to define a first region and a second region within the second chamber. The first region is in fluid communication with at least one row of tubes from the plurality of tubes. Further, the method introduces the coolant from the first region to a second heat exchanger.
Other features and aspects of this disclosure will be apparent from the following description and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic view of an exemplary machine, according to an aspect of the present disclosure;

FIG. 2 is a schematic representation of a cooling system;

FIG. 3 is a perspective view of a cooling system according to an aspect of the present disclosure;

FIG. 4 is a top view of a second chamber connected to a second heat exchanger along the plane 4-4 shown in FIG. 3; and

FIG. 5 is a flow chart of a method for cooling a working fluid in a hydraulic system according to an aspect of the present disclosure.

DETAILED DESCRIPTION

Wherever possible the same reference numbers will be used throughout the drawings to refer to the same or the like parts. FIG. 1 illustrates an exemplary machine 100 according to one aspect of the present disclosure. As illustrated, the machine 100 may embody a track type tractor. Alternatively, the machine may include, but is not limited to, a backhoe loader, a skid steer loader, a wheel loader, a motor grader, and the like. It should be understood that the machine 100 may embody any wheeled or tracked machine associated with mining, agriculture, forestry, construction, and other industrial applications.
As illustrated in FIG. 1, the machine 100 may include a power source 102, a transmission system 104, and a propulsion system 106. In one embodiment, the power source 102 may include, for example, a diesel engine, a gasoline engine, a gaseous fuel powered engine such as a natural gas engine, a combination of known sources of power or any other type of engine apparent to one of skill in the art. The transmission system 104 may be communicably coupled to the power source 102. The transmission system 104 may include coupling elements for transmitting a drive torque from the power source 102 to the propulsion system 106. As illustrated in FIG. 1, the propulsion system 106 may include a track 108 having ground engaging elements configured to propel the machine 100 on a ground.
Further, the machine 100 may include a load lifting assembly 110 having a lift arm 112, one or more hydraulic actuator 114 and a ground engaging tool 116, such as a blade or bucket. The ground engaging tool 116 is configured to collect, hold and convey material and/or heavy objects on the ground. The hydraulic actuators 114 may be configured to effectuate the movement of the lifting assembly 110 based on an operator command provided by an operator of the machine 100. The operator command may be received through various input devices present within an operator cabin 118 of the machine 100.
FIG. 2 illustrates a block diagram of a cooling system 200 connected to the power source 102, according to one embodiment of the present disclosure. The cooling system 200 may include a first heat exchanger 202 and a second heat exchanger 204 in fluid communication with each other. The first heat exchanger 202 is configured to dissipate heat from a coolant received from the power source 102. A person of ordinary skill in the art will appreciate that any suitable coolant known in the art may be used. For example, the coolant may include distilled water or a mixture of water, antifreeze and other additives. The second heat exchanger 204 is configured to cool a working fluid associated with a hydraulic system. As shown in FIG. 2, the first heat exchanger 202 may be fluidly connected to the power source 102 through a plurality of fluid passages 206, 208. The first heat exchanger 202 may be configured to receive a flow of the coolant from the power source 102 via the fluid passage 206. After cooling, the coolant may flow from the first heat exchanger 202 towards the power source 102 via the fluid passage 208.
As shown in FIG. 3, an inlet port 302 may be provided on the first heat exchanger 202. The inlet port 302 of the first heat exchanger 202 may be connected to the fluid passage 206, which in turn is connected to the power source 102. The inlet port 302 is configured to receive the coolant from the power source 102 via the fluid passage 206. Further, an outlet port 304 may also be provided on the first heat exchanger 202. The outlet port 304 may be connected to the power source 102 via the fluid passage 208.
In one embodiment, the first heat exchanger 202 may be a tube radiator, preferably a grommeted tube radiator. The first heat exchanger 202 may include a first chamber 306 and a second chamber 308. The first chamber 306 and the second chamber 308 may be fluidly connected to each other through a plurality of tubes 310. The plurality of tubes 310 connecting the first chamber 306 with the second chamber 308 may be placed substantially vertical within the first heat exchanger 202, such that the tubes 310 are arranged in a plurality of rows. The tubes 310 may be configured to convey the coolant from the first chamber 306 to the second chamber 308. It should be noted that each of the plurality of rows of tubes 310 may conduct the coolant from the first chamber 306 to the second chamber 308 independent of each other. The tubes 310 may be arranged in such a manner that one end of the tubes 310 is in fluid communication with the first chamber 306, while another end of the tubes 310 is in fluid communication with the second chamber 308.
Arrowheads shown in FIG. 3 are indicative of a direction of flow of a cooling medium 312. The cooling medium 312 may include, but not limited to, surrounding air, air from a fan, or any other source providing air flow within an enclosure housing the power source 102. As shown in FIG. 3, the plurality of tubes 310 may be placed such that the direction of the flow of the cooling medium 312 is substantially perpendicular to the plurality of tubes 310. It should be noted that the cooling medium 312 may be relatively cooler than the coolant flowing within the tubes 310 of the first heat exchanger 202. Accordingly, the cooling medium 312 flowing over the arrangement of the tubes 310 of the first heat exchanger 202 may be configured to lower a temperature of the coolant flowing within the tubes 310 by means of heat exchange.
One of ordinary skill in the art will appreciate that the drop in temperature of the coolant may vary in each of the row of tubes 310. The drop in temperature may depend on the location or position of the row of tubes 310 relative to the direction of the flow of the cooling medium 312. More specifically, the temperature drop in the coolant flowing in the initial few rows of tubes 310 may be relatively more than the drop in temperature experienced by the coolant flowing through the row of tubes 310 situated further away from the direction of flow of the cooling medium 312. For example, the temperature drop in first row of tubes 310 may be approximately 25% higher than the temperature drop in the row of the tubes 310 situated further away. Moreover, the temperature of the cooling medium 312 may continue to increase as the cooling medium 312 flows through the first heat exchanger 202, based on heat exchanged with the coolant flowing through the tubes 310. It should be understood that the first heat exchanger 202 is not restricted to the grommeted tube radiator, and may be any suitable type of heat exchanger for effective heat transfer between the coolant and the cooling medium 312.
FIG. 4 is a top view of the second chamber 308 looking down from the plane 4-4 shown in FIG. 3. For clarity, the tubes 310 within the first heat exchanger 202 are not shown. The present disclosure relates to a baffle 402 provided in the first heat exchanger 202. The baffle 402 may be configured as a plate which may be made from any suitable material, such as, for example, corrosion resistive metal, plastic, hybrid material, and the like. Parameters like length and thickness may vary according to the application. Referring to FIG. 4, the baffle 402 may be placed within the second chamber 308 of the first heat exchanger 202. The baffle 402 is configured to divide the second chamber 308 into a first region 404 and a second region 406.
As shown in FIG. 4, the baffle 402 may be placed in such a way that the first region 404 is in fluid communication with at least one row of tubes 310. The placement of the baffle 402 within the second chamber 308 is such that the at least one row of tubes 310 provided in the first region 404 is configured to receive the cooling medium 312 prior to the remaining tubes 310 present in the second region 406. Accordingly, the coolant leaving the at least one row of tubes 310 of the first region 404 may be relatively cooler than that of the second region 406. In other words, the row of tubes 310 in fluid communication with the first region 404 receives the coolest cooling medium 312, and thus the coolant in the first region is relatively cooler that that of the second region.
As shown in FIG. 2, the first heat exchanger 202 is in fluid communication with the second heat exchanger 204 via a fluid passage 210. More specifically, as shown in FIGS. 3 and 4, the second chamber 308 of the first heat exchanger 202 further includes an outlet 314 configured to fluidly connect the first region 404 with the second heat exchanger 204. The coolant leaving the at least one row of tubes 310 in the first region 404 may flow towards the second heat exchanger 204 through the outlet 314. An inlet 316 of the second heat exchanger may be in fluid communication with the outlet 314 of the first heat exchanger 202. The coolant received from the first heat exchanger 202 may be used to cool the working fluid in the second heat exchanger 204. It should be understood that the location of the baffle 402 in the second chamber 308 may depend on the amount of heat dissipation required by the working fluid present in the second heat exchanger 204. For example, the first region 404 may proportionately include more number of rows of tubes 310 if a relatively larger quantity of heat dissipation is required within the second heat exchanger 204.
In one embodiment, the second heat exchanger 204 may be a shell and tube type heat exchanger for exchanging heat between the working fluid used in hydraulic system and the coolant from the first heat exchanger 202. In another embodiment, the second heat exchanger 204 may be an in-tank cooler that may be placed in the first region 404 of the second chamber 308. More particularly, as shown in FIGS. 2 and 3, the working fluid may include oil received from an oil tank 212 via a fluid passageway 214 and an inlet 318 on the second heat exchanger. A person of ordinary skill in the art will appreciate that the secondary heat exchanger 204 is not restricted to shell and tube type heat exchanger and may be any suitable type of heat exchanger known in the art. The cooled working fluid may exit the second heat exchanger 204 via an outlet 320 provided on the second heat exchanger 204. This cooled working fluid may flow through a fluid passageway 216 to any suitable application on the machine 100.
Further, referring to FIGS. 2-4, the coolant used for cooling the working fluid in the second heat exchanger 204 may be returned to the first heat exchanger 202 via a fluid passageway 218. This fluid passageway 218 may be defined by an outlet 322 of the second heat exchanger 204 in fluid connection with an inlet 324 located on the second chamber 308 of the first heat exchanger 204.
In one embodiment, the second chamber 308 of the first heat exchanger 202 may further include the outlet port 304 to fluidly connect the first heat exchanger 202 with the power source 102 via the fluid passage 208. The coolant from the second chamber 204 of the first heat exchanger 202 may be conveyed to the power source 102 from the outlet port 304 via the fluid passageway 208. It should be noted that this coolant may include the coolant leaving the row of tubes 310 present in the second region 406 of the first heat exchanger 202. Additionally, the coolant may also include the coolant received from the outlet 322 of the second heat exchanger 204 which is in communication with the second region 406 of the first heat exchanger 202.

INDUSTRIAL APPLICABILITY

In the present disclosure the coolant from the at least one row of tubes 310 of the first heat exchanger 202 is utilized to cool the working fluid in the second heat exchanger 204. Since the at least one row of tubes 310 are provided in the direction of the flow of the cooling medium 312, the coolant leaving this region of the first heat exchanger 202 is approximately 25% cooler than that leaving the second region. Further, the second heat exchanger 204 may remain in the cooling circuit of the first heat exchanger 202 having minimal or no effect on the flow rate and overall cooling system performance.
Referring to FIG. 5, a flow chart for a method 500 for cooling the working fluid in the hydraulic system is shown. At step 502, the coolant may be received in the first chamber 306 of the first heat exchanger 202. The coolant may flow from the power source 102 via the fluid passage 206 to the inlet port 302 of the first heat exchanger 202. At step 504, the coolant may be introduced into the plurality of tubes 310 connecting the first chamber 306 and the second chamber 308 of the first heat exchanger 202. Further, at step 506, the coolant may be directed towards the second chamber 308 of the first heat exchanger 202 through the plurality of tubes 310.
As the coolant is conveyed from the first chamber 306 to the second chamber 308, the coolant may undergo the drop in temperature as a result of the heat exchange with the cooling medium 312 flowing over the plurality of tubes 310. At step 508, the baffle 402 may be provided within the second chamber 308. As described earlier, the baffle 402 may divide the second chamber 308 into the first region 404 and the second region 406. The first region 404 is in fluid communication with the at least one row of plurality of tubes 310. Further, the first region 404 may be provided in the direction of the cooling medium 312.
The cooling medium 312 may flow over the at least one row of tubes 310 in the first region 404 prior to that of the tubes 310 in the second region 406. As a result, the temperature drop of the coolant in the at least one row of tubes 310 of the first region 404 may be relatively higher than that of the second region 406. Further, at step 510, the coolant from the first region 404 may be introduced into the second heat exchanger 204. The coolant from the first region 404 of the second chamber 308 can be fed through the outlet 314 of the first region 404 to the inlet 316 of the second heat exchanger 204 through the fluid passage 210.
In one embodiment, the second heat exchanger 204 may utilize the coolant from the first region 404 of the second chamber 308 to cool the working fluid fed from the hydraulic system into the second heat exchanger 204. In one embodiment, the working fluid may be directed towards any suitable application in the machine 100. Further, the coolant from the second heat exchanger 204 may be fed back to the second chamber 308 of the first heat exchanger 202 through the outlet 322 of the second heat exchanger 204. The coolant from the first heat exchanger 202 may then be directed towards the power source 102 via the fluid passageway 208.
A person of ordinary skill in the art will appreciate that the connections described herein are exemplary and do not limit the scope of the disclosure. Also, the present disclosure has been explained with reference to the cooling system 200 for cooling the working fluid of the hydraulic system. However, the disclosure may also be utilized on other applications having similar requirements.
While aspects of the present disclosure have been particularly shown and described with reference to the embodiments above, it will be understood by those skilled in the art that various additional embodiments may be contemplated by the modification of the disclosed machines, systems and methods without departing from the spirit and scope of what is disclosed. Such embodiments should be understood to fall within the scope of the present disclosure as determined based upon the claims and any equivalents thereof.

Claims

What is claimed is:

1. A cooling system comprising:

a first heat exchanger comprising:

a plurality of tubes in fluid communication with a first chamber and a second chamber, the tubes being arranged in a plurality of rows;

a baffle located in the second chamber, the baffle configured to divide the second chamber into a first region and a second region, wherein the first region is in fluid communication with at least one row of tubes; and

an outlet in fluid communication with the first region; and

a second heat exchanger comprising an inlet, wherein the inlet of the second heat exchanger is in fluid communication with the outlet of the first region.

2. The cooling system of claim 1, wherein the first heat exchanger further comprises an inlet port in fluid communication with the first chamber and a power source, wherein the inlet port is configured to receive coolant from the power source.

3. The cooling system of claim 1, wherein the first heat exchanger further comprises an outlet port in fluid communication with the second region of the second chamber and a power source, wherein the outlet port is configured to provide the coolant to the power source.

4. The cooling system of claim 1, wherein the second heat exchanger further comprises an outlet in fluid communication with the second region of the second chamber.

5. The cooling system of claim 1, wherein the at least one row of tubes in fluid communication with the first region is placed in a direction of flow of a cooling medium.

6. The cooling system of claim 1, wherein the first heat exchanger is a tube type radiator including multiple rows of tubes.

7. The cooling system of claim 1, wherein the second heat exchanger is a shell and tube type heat exchanger.

8. The cooling system of claim 1, wherein the baffle is a plate.

9. A method for cooling a working fluid in a hydraulic system comprising:

receiving a coolant in a first chamber of a first heat exchanger;

introducing the coolant into a plurality of tubes, the tubes being arranged in a plurality of rows;

directing the coolant through the plurality of tubes towards a second chamber of the first heat exchanger;

providing a baffle in the second chamber, the baffle configured to define a first region and a second region within the second chamber, wherein the first region is in fluid communication with at least one row of tubes from the plurality of tubes; and

introducing the coolant from the first region to a second heat exchanger configured to remove heat from the working fluid.

10. The method of claim 9 further comprising receiving the coolant in the first chamber through a power source.

11. The method of claim 9 further comprising placing the at least one row of tubes, in fluid communication with the first region, in a direction of flow of a cooling medium.

12. The method of claim 9 further comprising directing the coolant from the second heat exchanger to a second region of the first chamber.

13. A machine comprising:

a power source;

a first heat exchanger comprising:

an outlet in fluid communication with the first region; and

14. The machine of claim 13, wherein the first heat exchanger further includes an inlet port in fluid communication with the first chamber and a power source, wherein the inlet port is configured to receive a coolant from the power source.

15. The machine of claim 13, wherein the first heat exchanger further includes an outlet port in fluid communication with the second region of the second chamber and a power source, wherein the outlet port is configured to provide a coolant to the power source.

16. The machine of claim 13, wherein the second heat exchanger further includes an outlet in fluid communication with the second region of the second chamber.

17. The machine of claim 13, wherein the at least one row of tubes in fluid communication with the first region is placed in a direction of flow of a cooling medium.

18. The machine of claim 13, wherein the first heat exchanger is a tube type radiator including multiple row of tubes.

19. The machine of claim 13, wherein the second heat exchanger is a shell and tube type heat exchanger.

20. The machine of claim 13, wherein the baffle is a plate.