Liquid purification or separation – Flow – fluid pressure or material level – responsive – Fluid pressure responsive by-pass
Reexamination Certificate
2000-11-30
2002-11-12
Drodge, Joseph W. (Department: 1723)
Liquid purification or separation
Flow, fluid pressure or material level, responsive
Fluid pressure responsive by-pass
C210S137000, C210S254000, C210S259000, C210S321650, C210SDIG005
Reexamination Certificate
active
06478953
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to the lubrication and hydraulic and electric insulating fluid industry, and particularly to an apparatus and a process used for the removal of particulate contaminants and free, emulsified, or dissolved water from oil.
2. Discussion of the Related Art
Oil is used in lubrication and hydraulic systems. It is also used as an electrical insulating fluid. It is widely recognized that the presence of particulate contamination and water have deleterious effects on the oil in such systems, the components in the systems, and the operation of the systems. It is well known that corrosion, reduced dielectric strength, oil oxidation, chemical wear and tear, reduced bearing fatigue life and loss of lubricity may result when water contamination enters a lubrication or hydraulic system. These deleterious effects can be directly attributed to water present in free, emulsified or dissolved form. It is also well known that particulate contamination can cause increased wear and tear, reduced bearing fatigue life, and reduced dielectric strength.
The devices and systems that have been used to remove water contamination include settling tanks or reservoirs, centrifuges, water absorbing filters, and vacuum dehydration oil purifiers. Devices used to remove particulate contamination include filters. However, these have had significant limitations in either their water removal capabilities, particulate contamination removal capabilities, ease of operation, capital costs, or operating costs.
SUMMARY OF THE INVENTION
The present invention details a device that enables the removal of particulate contamination and free, emulsified or dissolved water from oils. This device is such that it may be used on mobile equipment while in operation and moving, as well as on stationary equipment and processes. The operation of this process is simple, while the equipment in question is small and compact making it practical and cost effective for systems of all sizes.
Specifically, this invention relates to a device that employs a filter to selectively remove particulate contamination (above a desired particle size) and a dehydrator to selectively remove the water from the oil. The use of a membrane based dehydrator has been detailed in co-pending U.S. patent application Ser. No. 09/321,887 and 09/552,369 filed by Applicant's assignee.
Significant efforts have been made to remove particulate contamination and water from oil in order to provide the clean, dry oil necessary for optimal performance of these systems. It is also known that particulate contamination is a greater challenge in these systems than is moisture ingression, therefore, it is often desirable to have a system with a large filter and a proportionally smaller dehydrator. In a situation such as this, it would be unnecessary to process the entire volumetric flow of oil through the dehydrator.
Consequently, it is desirable to have a system that filters the full volumetric flow of oil, but dehydrates only a portion of this flow.
In addition, during cold start up of the system, the viscosity of the oil is significantly higher than the viscosity at the mean operating temperature. The pressure drop required to flow this volumetric flow of oil through the dehydrator may be significantly greater than at mean operating conditions. It is preferable, in this situation to process only a portion of the total volumetric flow of oil through the dehydrator.
If the filter dehydrator is operated outside its design parameters it is possible that membrane, or the seals in the dehydrator may be compromised. This could lead to the transmission of the oil into the permeate chamber. It is preferable to have a discharge chamber at the outlet of the permeate stream designed to capture any liquids in this part of the system. The liquid capture may be sensed by means of a float valve, liquid level control or any other means known in the art. Upon sensing the presence of liquid in the discharge chamber it is preferable to shut off the sweep or vacuum to prevent further loss of oil. It may also be preferable to trigger an alarm upon detecting the presence of liquid in the discharge chamber.
In one embodiment of the present invention a method is disclosed to dehydrate industrial fluids which includes the steps of:
(a) providing an air sweep to remove the water extracted from the oil;
(b) providing a means to filter the air sweep;
(c) providing a means to remove liquid water contamination of the air sweep;
(d) providing a means to dehydrate the air sweep prior to contacting the filter dehydrator;
(e) removing, from the feed side of the dehydrator, the oil that is dehydrated,
(f) providing for a pressure control valve between the outlet of the filter and inlet of the dehydrator that enables the bypass of the oil around the dehydrator.
(g) providing for this pressure control valve to be intrinsic or extrinsic to the entire system.
(h) providing the possibility for the clean, dry oil exiting from the dehydrator to merge with the bypass stream;
(i) providing, in the sweep outlet, a sweep discharge chamber that is able to sense the presence of liquid in the sweep and shut off the sweep flow to prevent loss of oil.
In another embodiment of the present invention, an apparatus is provided for providing clean, dry, oil which includes:
(a) a vessel containing at least a filter interposed in said vessel in such a fashion as to divide the interior of the vessel into at least one feed-side space and one filtrate-side space;
(b) at least one inlet opening to the feed-side space;
(c) at least one outlet opening to the filtrate-side space;
(d) at least another vessel containing at least a dehydrator interposed in said vessel in such a fashion as to divide the interior of the vessel into at least one dehydrator feed side space and one dehydrator permeate space;
(e) at least one inlet opening to the dehydrator feed-side space;
(f) at least one outlet opening to the dehydrator permeate space;
(g) at least a pressure control valve interposed between the inlet to the dehydrator and the system outlet;
(h) a partial bypass that would be activated by the pressure control value;
(i) at least a sweep discharge chamber designed to capture any liquids in the sweep;
(j) and at least a system designed to shut off the sweep flow upon a capture of liquids in the sweep chamber.
Thus, it is an object of the present invention to provide an improved filter/dehydrator for the removal of particulate contaminants and free, emulsified, or dissolved water from oil.
Another object of the present invention is to overcome the shortcomings of conventional oil dehydration techniques, and provide a new device that overcomes these limitations.
Another object of the present invention is to provide a filter dehydrator that removes free, emulsified or dissolved water from oils.
Another object of the present invention is to provide a filter dehydrator that removes particulate contamination from oils.
A further object of the present invention is to provide a means of protecting the dehydrator from system pressures that exceed its design criteria. This may be accomplished by means of a pressure control valve that enables a portion of the fluid to bypass the dehydrator.
A further object of the present invention is to provide a means of protecting the dehydrator from differential pressures that exceed its design criteria. This may be accomplished by means of a pressure control valve that enables a portion of the fluid to bypass the dehydrator.
A further object of the present invention is to provide a means for the removal of water from the system after it has been extracted from the oil.
A further object of the present invention is to provide a means for preventing the loss of the oil in the stream removing the water from the system.
A further object of the present invention is to provide a pump that drives the fluid through the filter dehydrator.
A further object of the present invention is to provide a filter dehydrator that is simple to op
Burban John H.
Cuta Craig J.
Kolstad David
Spearman Michael R.
Thundyil Mathews
Cecil Terry K.
Drodge Joseph W.
Marshall & Melhorn LLC
Porous Media Corporation
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