Locomotive air dryer bypass system

Abstract

An air dryer bypass system that can protect the air supply system, including the air dryer, from damage that will occur if compressed air is allowed to flow through the air dryer because of an event that has compromised the ability of the air dryer to operate properly. The system has a valve with an inlet coupled to a first main reservoir of a locomotive air supply system, a first outlet coupled to an inlet of a locomotive air dryer, and a second outlet coupled to a second main reservoir downstream of an outlet of the air dryer. A pilot for moving the valve between a first position wherein the inlet is coupled to the first outlet and second position there the inlet is coupled to the second outlet. The valve is biased into the second position and a controller coupled to the pilot is programmed to move the valve to the first position when the air dryer is powered.

Description

TITLELOCOMOTIVE AIR DRYER BYPASS SYSTEMBACKGROUND1. FIELD OF THE INVENTION

[0001] The present disclosure relates to locomotive air dryers and, more specifically, to an approach that can protect the air dryer from damage during loss of power or an internal failure.2. DESCRIPTION OF THE RELATED ART

[0002] A typical locomotive air supply system consists of a compressor and two main reservoirs in series, MR1 and MR2. An air dryer is usually installed between MR1 and MR2, so that dry air is delivered to MR2. Air dryers for railway use are typically a “pressure-swing absorption” type, also referred to as a twin-tower, desiccant air dryer. Whenever the compressor is running and the air dryer is powered, the air dryer cycles between two columns of desiccant to direct wet product air through one column to remove the water vapor, thus resulting in dry product air, while simultaneously taking a fraction of the dry product air and counter- flowing it through the other previously saturated column of desiccant to remove accumulated moisture. If the air dryer is powered off or has experienced a failure mode and is still subjected to air flow, however, a significant amount of water and condensate will accumulate in the air dryer, which will flood the desiccant and permanently damage the air dryer. This may also occur in the event of flooding, freezing, or some form of obstruction. Accordingly, there is a need in the art for an approach that can protect an air dryer from the consequences of an extended amount of air flow if the air dryer is not operational.BRIEF SUMMARY

[0003] The present invention provides an air dryer bypass system that can protect the air dryer from damage in the event of a loss of power or other failure mode that could result in damage to the air dryer if compresses air is allowed to flow through the air dyer. In an embodiment, the air dryer bypass system includes a valve coupled to a first main reservoir of a locomotive air supply system, a first outlet coupled to an inlet of a locomotive air dryer, and a second outlet coupled to a second main reservoir downstream of an outlet of the air dryer. The valve includes a pilot for moving the valve between a first position wherein the inlet is coupled to the first outlet and second position there the inlet is coupled to the second outlet. The valve is biased into the second position so that the valve normally bypasses the air dryer. A controller is coupled to the pilot and programmed to move the valve from the second position to the first position if the locomotive air dryer is powered. The system furtherincudes a check valve positioned between the second outlet of the valve and the outlet of the air dryer to prevent backflow from the bypass to the air dryer. The controller may be programmed to communicate with an electronic air brake system, or sub-system such as an electronic air brake, to indicate whether the valve is in the first position or the second position. The controller may be programmed to determine whether the air dryer is powered, has experienced a failure, or has another condition such as an obstruction or frozen component that is interfering with proper operation. The controller may be programmed to determine whether the air dryer is in a failure state that could damage the air dryer if compressed air is passed through the air dryer. The controller may be incorporated into the air dryer. The controller may instead be separate from the air dryer.

[0004] In another embodiment, the present invention includes method of protecting an air dryer, comprising the steps of coupling a valve having an inlet to a first main reservoir of a locomotive air supply system, coupling a first outlet of the valve to an inlet of a locomotive air dryer, and then coupling a second outlet of the valve a second main reservoir downstream of an outlet of the air dryer. The method further includes the step of piloting the valve between a first position wherein the inlet is coupled to the first outlet and second position there the inlet is coupled to the second outlet, wherein the valve is biased into the second position when a controller determined that the locomotive air dryer is unpowered. BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

[0005] The present invention will be more fully understood and appreciated by reading the following Detailed Description in conjunction with the accompanying drawings, in which:

[0006] FIG. 1 is a schematic of a locomotive air supply system for use with an air dryer bypass system according to the present invention.

[0007] FIG. 2 is a schematic of the air dryer bypass system according to the present invention.DETAILED DESCRIPTION

[0008] Referring to the figures, wherein like numeral refer to like parts throughout, there is seen in FIG. 1 a locomotive air supply system 10 having an air compressor 12, an aftercooler 14, first and second main reservoirs MR1 and MR2, and a two-tower desiccant air dryer 16 having an inlet for receiving compressed air from MR1. Second main reservoir MR2 is coupled downstream of air dryer 16 for receiving the compressed, dried air and then providing the compresses air to the braking system 18 of the train. A check valve 20 is positioned between the first and second main reservoirs MR1 and MR2. A prefiltration stage22 is associated with air dryer 16 and includes a drain valve 24 that is operated according to a drain valve purge cycle time. In the event that air dryer 16 is not operational, such as when air dryer is unpowered, is unplugged, or has experienced a failure of any kind, compresses air will continue to flow from MR1 to MR2. As air dryer 16 is not capable of performing its regeneration cycle or purging accumulated water and condensate. Air dryer 16 is therefore at risk of permanent damage.

[0009] Referring to FIG. 2, an air dryer bypass system 40 according to the present invention includes a valve 42 positioned upstream of air dryer 16. Valve 42 includes an inlet 44 coupled to MR1, a first outlet 46 coupled to air dryer 16, and a second outlet 48 coupled to a bypass line 50 that circumvents air dryer 16 and leads directly to MR2. Air dryer bypass system 40 further includes a check 52 position downstream of air dryer 16 and upstream of bypass line 50 to prevent backflow of compresses air in bypass line 50 to air dryer 16. Valve 42 is moveable between a first position, where valve 42 coupled inlet 44 to first outlet 46 so that MR1 is coupled to air dryer 16, and a second position, where inlet 44 is coupled to second outlet 48 and bypass line 50 so that airflow bypasses air dryer 16 and proceeds to MR2 without passing through air dryer 16. Valve 42 includes a pilot 54 that is operated by a controller 56. For example, the existing controller for air dryer 16 that is programmed to control the operation of air dryer 16, including the timing of regeneration and purse cycles, may be additionally programmed to function as controller 56 of air dryer bypass system 40. Controller 56 may be provided separately as a dedicated device alongside air dryer bypass system 40 in the manifold used to connect air dryer 16 to the locomotive air supply system 10. This option would allow air dryer bypass system 40 of the present invention to be easily retrofit into locomotive air supply systems 10 having legacy air dryers 16.

[0010] Valve 42 is preferably biased by a preload 58 so that the second position is the normal or default position and valve 42 must be actively driven by pilot 54 to allow compressed air to flow from MR1 to inlet 30 of air dryer 16. Valve 42 may be a magnet valve as is conventionally known in the art. It should be recognized by those of skill in the art that, in the event that air dryer 16 is unpowered, whether intentionally or through a failure, air dryer bypass system 40 will become operational to prevent the flow of compresses air through air dryer 16. Air dryer bypass system 40 therefore operates to protect air dryer 16 from flooding of the desiccant and any resulting permanent damage to the air dryer. When air dryer 16 is properly powered or the failure condition has been corrected, valve 42 of air dryer bypass system 40 can be driven to the first position where MR1 is coupled to air dryer 16 so that normal air supply drying operations can resume.

[0011] As further seen in FIG. 2, controller 56 may be interconnected to the electronic air brake 60 of the locomotive (not shown) where locomotive air supply system 10 is located. As is known in the art, electronic air brake 60 is in communication with a locomotive operator display 62 positioned locally in the cab of the locomotive where locomotive supply air system 10 is located. It should be noted that while particular terminology used herein for various hardware and software equipment is most commonly used with the electronic air brake system known as the CCB II® computer controlled brake available from New York Air Brake, LLC of Watertown, New York, other electronic air brake systems may include air dryer bypass system 40. Electronic air brake 60 may also in remote communication with a back office system 64, such as a railroad locomotive maintenance system, that is tasked with managing a fleet of locomotives including those outfitted with air dryers 16 and air dryer bypass system 40. Air dryer bypass system can thus provide a live display status, along with real time notification to back office / operator dispatch and back office maintenance notifications to the railroad operation that action is required.Air dryer bypass system 40 may thus help improve reliability of locomotive air supply system 10 as well as air dryer 16, whether incorporated into a particular manufacturer’s air dryer 16 or retrofitted for use with a legacy air dryer 16 of any manufacturer.

[0012] If controller 56 comprises a software update to the legacy air dryer controller, controller 56 may be programmed to perform diagnostics on the operation of air dryer 16 so that any failures other than a complete loss of power that could still result in damage to air dryer 16 if compressed air continued to flow through air dryer 16 will also result in air dryer bypass system 40 circumventing air dryer 16. The status of bypass system 40, and any diagnostics, can also be communicated to electronic air brake 60 for display on locomotive operator display 62. For example, loss of power events can be configured to trigger air dryer bypass system 40 as well as corresponding display on locomotive operator display 62. Similarly, any number of internal air dryer faults not associated with a loss of power can also be configured to trigger air dryer bypass system 40 as well as corresponding display on locomotive operator display 62. Finally, controller 56 may also be programmed to activate air dryer bypass system 40 in response to a manual command from the locomotive operator or a technician so that air dryer 16 is circumvented for repair or maintenance operations.

[0013] While controller 56 preferably comprises a computing apparatus having software implemented logic, it should be recognized by those of skill in the art that the decision-making describe above could also be implemented through the use of a pneumatic and mechanical circuit employing pressure responsive valves and switches to determinedwhen to trigger the use of the bypass circuit and to actually trigger such use. In addition, the apparatuses described herein may be implemented using hardware components, software components, and / or a combination thereof. For example, the apparatuses and the components described herein may be implemented using one or more general-purpose or special purpose computers, such as, for example, a processor, a controller, an arithmetic logic unit (ALU), a digital signal processor, a microcomputer, a field programmable array (FPA), a programmable logic unit (PLU), a microprocessor, or any other device capable of responding to and executing instructions in a defined manner. The processing device may run an operating system (OS) and one or more software applications that run on the OS. The processing device also may access, store, manipulate, process, and create data in response to execution of the software. For purpose of simplicity, the description of a processing device is used as singular; however, one skilled in the art will be appreciated that a processing device may include multiple processing elements and / or multiple types of processing elements. For example, a processing device may include multiple processors or a processor and a controller. In addition, different processing configurations are possible, such as parallel processors.

[0014] The software may include a computer program, a piece of code, an instruction, or some combination thereof, for independently or collectively instructing or configuring the processing device to operate as desired. Software and / or data may be embodied in any type of machine, component, physical equipment, virtual equipment, computer storage medium or device, to be interpreted by the processing device or to provide an instruction or data to the processing device. The software also may be distributed over network coupled computer systems so that the software is stored and executed in a distributed fashion. The software and data may be stored by one or more computer readable storage media.

Claims

CLAIMSWhat is claimed is:

1. An air dryer bypass system, comprising: a valve having an inlet configured to be coupled to a first main reservoir of a locomotive air supply system, a first outlet configured to be coupled to an inlet of a locomotive air dryer, and a second outlet configured to be coupled to a second main reservoir downstream of an outlet of the air dryer, and a pilot for moving the valve between a first position wherein the inlet is coupled to the first outlet and second position there the inlet is coupled to the second outlet, wherein the valve is biased into the second position; and a controller coupled to the pilot and programmed to move the valve from the second position to the first position if the locomotive air dryer is unpowered.

2. The air dryer bypass system of claim 1, further comprising a check valve positioned between the second outlet of the valve and the outlet of the locomotive air dryer.

3. The air dryer bypass system of claim 1, wherein the controller is programmed to communicate with an electronic air brake system component to indicate whether the valve is in the first position or the second position.

4. The air dryer bypass system of claim 1, wherein the controller is programmed to determine whether the locomotive air dryer is powered.

5. The air dryer bypass system of claim 1, wherein the controller is programmed to determine whether the locomotive air dryer is in a failure state.

6. The air dryer bypass system of claim 1, wherein the controller is programmed to determine whether the locomotive air dryer can provide an adequate amount of dry air flow to the second main reservoir.

7. The air dryer bypass system of claim 1, wherein the controller is separate from the locomotive air dryer.

8. The air dryer bypass system of claim 1, wherein the controller is incorporated into the locomotive air dryer.

9. A method of protecting an air dryer, comprising the steps of: coupling a valve having an inlet to a first main reservoir of a locomotive air supply system; coupling a first outlet of the valve to an inlet of a locomotive air dryer; coupling a second outlet of the valve a second main reservoir downstream of an outlet of the air dryer; andpiloting the valve between a first position wherein the inlet is coupled to the first outlet and second position there the inlet is coupled to the second outlet, wherein the valve is biased into the second position when the locomotive air dryer is unpowered.

10. The method of claim 9, further comprising a check valve positioned between the second outlet of the valve and the outlet of the locomotive air dryer.

11. The method of claim 9, wherein a controller associated with the valve is programmed to communicate with an electronic air brake system component to indicate whether the valve is in the first position or the second position.

12. The method of claim 11, wherein the controller is programmed to determine whether the locomotive air dryer is powered.

13. The method of claim 11, wherein the controller is programmed to determine whether the locomotive air dryer is in a failure state.

14. The method of claim 11, wherein the controller is programmed to determine whether the locomotive air dryer can provide an adequate amount of dry air flow to the second main reservoir.

15. The method of claim 11, wherein the controller is separate from the locomotive air dryer.

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