Aircraft hydraulic fluid purification system and method

#The present invention relates to a system and method for storing and purifying hydraulic fluid and, more particularly, to a system and method for storing and purifying the hydraulic fluid in one or more aircraft hydraulic fluid systems.

#Aircraft include various systems that are operated and controlled using hydraulic fluid. The hydraulic fluid used is generally a petroleum-based fluid, such as oil. When the hydraulic fluid is placed in the aircraft hydraulic systems, it is substantially free of water, solvents, particulate, and other unwanted contaminants. However, over time such contaminants can infiltrate the hydraulic system and contaminate the hydraulic fluid. If such contaminants are present in the hydraulic fluid, hydraulic system performance can be adversely affected and, in some instances, can result in corrosion of one or more hydraulic system components. Thus, the hydraulic fluid in aircraft hydraulic systems is periodically subjected to a purification process.

#The hydraulic fluid in aircraft hydraulic systems is purified, in many instances, by connecting various pieces of portable equipment to the aircraft. For example, a portable vacuum purification unit and a ground cart that includes a hydraulic pump and various flow lines may be coupled to the aircraft hydraulic system. The hydraulic pump in the ground cart may be used to draw hydraulic fluid from the aircraft hydraulic system into the purification unit and then pump substantially purified hydraulic fluid from the purification unit back into the aircraft hydraulic system. In addition to these two pieces of equipment, a separate power generator may be required to power the purification unit and/or the hydraulic pump.

#FIG. 1 is a simplified schematic representation of a transportable ground cart with a hydraulic fluid purification system mounted thereon;

#FIG. 2 is a simplified piping schematic representation of a hydraulic fluid purification system according to an exemplary embodiment of the present invention that may be included on the cart of FIG. 1;

#FIG. 3 is partial schematic representation of the hydraulic fluid purification system of FIG. 2 according to an exemplary alternative embodiment; and

#A simplified schematic representation of a ground cart 100 with a hydraulic fluid purification system 200 mounted therein is depicted in FIG. 1. The ground cart 100 includes a housing 102 and varying numbers of rotationally mounted wheels 104, which allow the cart 100 to be readily transported to one or more aircraft. In addition to the hydraulic fluid purification system, various other systems and components may be mounted within the housing 102 to supply power and compressed air for various ground support operations. For example, in the depicted embodiment, an auxiliary power unit (APU) 106 is depicted. It should be appreciated that other systems and components may also be installed in the ground cart 100, but for the sake of clarity and ease of description, only a single APU is depicted.

#The APU 106 includes a combustor 108, a power turbine 112, and a compressor 114. During APU operation, the combustor receives fuel 116 from a fuel source (not illustrated) and supplies high energy air to the power turbine 112 causing it to rotate. The power turbine 112 includes a shaft 118 that is used to drive the compressor 114. The compressor 114 draws in ambient air 122, compresses it, and supplies compressed air 124 to one or more additional systems. It should be appreciated that the presently described embodiment is not limited to use with a cart 100 that includes an APU, and that various other devices and systems such as, for example, a diesel engine, may also be used. Furthermore, it should be appreciated that the presently described embodiment is not limited to use with a cart 100 that includes an APU or diesel engine or various other systems and components not further described below.

#The hydraulic fluid purification system 200, which is depicted more clearly in FIG. 2, includes a salvage tank 202, a first fluid conduit 204, a second fluid conduit 206, a purification module 208, and a valve system 210. The salvage tank 202 may be mounted on the cart in any one of numerous positions and configurations, and may be anyone of numerous sizes and shapes. For example, the salvage tank 202 may be a substantially closed, vented tank, or it may be an open tank. Preferably, the salvage tank 202 has an inner volume 212 that is at least sufficient to contain the entire volume of used hydraulic fluid that is being removed from a particular aircraft. In a particular preferred embodiment, the salvage tank inner volume is sufficient to contain the entire volume of hydraulic fluid in the hydraulic system of at least one aircraft.