The invention relates to an apparatus and a method for detecting the presence of water in a hydrocarbon fluid.
The presence of water in hydrocarbon fluids, such as used in aviation fuel, for example, has presented a problem for many years. Various types of systems are available for the analysis of fuel to determine the presence of water.
Presently, fuel filter monitors are employed to sense water in hydrocarbon fluids. Such monitors typically may include super absorbent polymers which absorb water that was present in transient fuel streams. While these systems have been reliable, it has been discovered that a degradation of water absorption occurs after an extended period of service. Also, it has been found that undesirable downstream migration of the super absorbent polymers has taken place under certain conditions.
It would be desirable to produce a fuel filter monitor utilizing changes in electrical capacitance of the water absorbing media of the monitor to sense the presence of water in a transient flow of fuel and to stop the fuel flow when an excessive amount of water is sensed.
Harmonious with the present invention, a fuel filter monitor utilizing changes in capacitance of the water absorbing media of the monitor to sense the presence of water in a transient flow of fuel and to stop the fuel flow when an excessive amount of water is sensed, has surprisingly been discovered.
In one embodiment, a fuel filter monitor for sensing contaminants in a transient flow of hydrocarbon fluid comprises a filter cartridge including an end cap; a capacitance sensor; and a pair of spaced apart electrodes in communication with the capacitance sensor and disposed in the end cap of the filter cartridge, the electrodes having a dielectric medium interdigitated therebetween, the medium capable of absorbing contaminants in the hydrocarbon fluid to vary the capacitance between the electrodes.
In another embodiment, a fuel filter monitor for sensing water in a transient flow of hydrocarbon fluid comprises a filter cartridge including an end cap; a capacitance sensor; and a pair of spaced apart electrodes in communication with the capacitance sensor and disposed in the end cap of the filter cartridge, the electrodes having a dielectric medium interdigitated therebetween, the medium capable of absorbing water in the hydrocarbon fluid to vary the capacitance between the electrodes.
The above and other objects and advantages of the invention will become readily apparent to those skilled in the art from reading the following descriptions of several embodiments of the invention when considered in the light of the accompanying drawings, in which:
The following detailed description and appended drawings describe and illustrate various exemplary embodiments of the invention. The description and drawings serve to enable one skilled in the art to make and use the invention, and are not intended to limit the scope of the invention in any manner. In respect of the methods disclosed and illustrated, the steps presented are exemplary in nature, and thus, the order of the steps is not necessary or critical.
In the embodiment shown, a first portion 28 and a second portion 29 cooperate to form the filter cartridge end cap 13. The first portion 28 can be joined to the second portion 29 by any means, such as a snap-fitting or a gluing, for example. It is understood that the filter cartridge end cap 13 can be formed from one integral piece as desired. While the filter monitor 10 has been shown embedded in the filter cartridge end cap 13, the filter monitor 10 can be disposed in a position intermediate a first end 31 and a spaced apart second end (not shown) of the filter cartridge 12 as desired.
The structural supports 14 and 26 may be formed from any suitable material such as metal or plastic, and include a plurality of spaced apart apertures formed therein for allowing the flow of fluid therethrough.
The filter media 16 and 24 can be formed from any suitable filtering material such as a fiberglass, for example.
The water absorbing dielectric medium 20 can be any water absorbing material as desired, such as cellulose, for example.
In use, the fluid is caused to flow into the filter cartridge 12 through the inlet apertures 27 formed in the filter cartridge end cap 13 and through the apertures formed in the first structural support 14. The fluid then flows through the first filter medium 16 where contaminants are removed therefrom. Thereafter, the fluid flows through the first electrode 18 and through the water absorbing dielectric medium 20 where water that may be present in the fluid is absorbed. The fluid then flows through the second electrode 22. It should be understood that the first electrode 18, the water absorbing dielectric medium 20, and the second electrode 22 cooperate to sense a capacitance of the fluid flowing therethrough. The capacitance is transmitted to a capacitance sensor 30 through a pair of electrical leads 32. After flowing through the second electrode 22, the fluid flows through the second filter medium 24 where additional contaminants are removed therefrom. Subsequently, the fluid flows out of the filter monitor 10 through the apertures formed in the second structural support 26. It should be appreciated that the fluid flows into the filter cartridge 12 through an outer wall thereof in an outside-in orientation in addition to flowing into the filter cartridge 12 through the inlet apertures 27 formed in the filter cartridge end cap 13.
When water is present in the flowing fluid, the water absorbing dielectric medium 20 displaces some fuel along with the absorbed water. This generates a capacitance increase, since the dielectric constant of water (80) is much larger than that of fuel (approx. 2.5). The capacitance increase is sensed by the capacitance sensor 30. The capacitance sensor 30 is configured to trigger appropriate valves (not shown) to stop the flow of fluid if the capacitance increase reaches a predetermined level. The predetermined level can be determined through experimental testing, for example. Since the electrical leads 32 carry the signal from the filter monitor 10, the capacitance sensor 30 can be positioned remotely therefrom.
It has been found that the performance of the water absorbing dielectric medium 20 can be maximized by adding a small amount of super absorbent polymer material therein. The polymer material is a better absorber of water than cellulose and therefore maximizes the increase in capacitance. In addition, the polymer regulates the capacitance, since the release of the water back into the fuel is slowed. However, it may be desirable to eliminate all super absorbent polymers from the monitor, in which case cellulose media may be used as described above.
In practice, multiple filter cartridges 34 are typically used in a single vessel 36 as shown in
The electrical leads 32, which can be molded into the filter cartridge end cap 13, provide an easy “plug-in” type connection from the capacitance sensor 30 to the filter monitor 10. Accordingly, the filter monitor 10 can be removed and replaced as desired.
Use of the filter monitor 110 is similar to that described above for
From the foregoing description, one ordinarily skilled in the art can easily ascertain the essential characteristics of this invention and, without departing from the spirit and scope thereof, can make various changes and modifications to the invention to adapt it to various usages and conditions.
This patent application is a Divisional of U.S. patent application Ser. No. 11/682,605 filed Mar. 6, 2007 which claims the benefit of U.S. Provisional Patent Application Ser. No. 60/782,174 filed on Mar. 13, 2006.
Number | Date | Country | |
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60782174 | Mar 2006 | US |
Number | Date | Country | |
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Parent | 11682605 | Mar 2007 | US |
Child | 12204100 | US |