Imperforate bowl: centrifugal separators – Including introduction of differing-weight fluids for...
Reexamination Certificate
1999-02-05
2001-05-29
Cooley, Charles E. (Department: 1723)
Imperforate bowl: centrifugal separators
Including introduction of differing-weight fluids for...
C494S056000, C494S060000, C494S067000, C494S079000, C494S084000, C494S901000
Reexamination Certificate
active
06238329
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to machines for separating mixed fluids. More particularly this invention relates to a rotating centrifuge-type machine which may be used, for example, to separate oil and water.
2. State of the Art
A fluid or mixture composed of two or more immiscible components, typically liquids of differing densities will, in the presence of the earth's gravitational field, will typically separate into layers with the least dense floating on top of the next most dense. With one component separated from the other, an interface or boundary between the two components is formed. The interface or boundary is typically quite distinct.
The process of gravitational separation may take a significant period of time based on, among other things, the volume of the involved fluids, the densities of the fluids, viscosity, temperature, and the like. To avoid delay and to expedite the separation process, it has long been recognized that the gravitational separation process may be greatly enhanced with regard to time and separation quality by replacing earth's “gravitational acceleration” with centrifugal force. That is, the fluids to be separated are placed in a container or vessel which is then spun to impose centrifugal forces. Based on, for example, the rotation rate, the force field thus provided may have a magnitude amounting to hundreds or even thousands of “g's.” The gravitational force at sea level is sometimes regarded as 1 “g” and is typically presented as an acceleration of 32 feet per second per second. Simply stated, the force to separate the liquids may be up to several hundreds or thousands of times stronger than the earth's gravitational force.
Centrifuges or separators to effect the separation of two liquids using centrifugal force are well known. U.S. Pat. No. 4,525,155 (Nilsson) discloses a typical centrifuge of the type for separating two liquids. However, the Nilsson machine appears to have a limited capacity or flow rate due to its relatively small weir structures. Some centrifuges need a complex and expensive construction in order to obtain satisfactory separation efficiency. U.S. Pat. No. 5,387,342 (Rogers, et al.) and U.S. Pat. No. 5,582,724 (Rogers, et al.), as well as U.S. Pat. No. 4,525,155 (Nilsson) are illustrative of such machines.
Centrifuges are not typically recognized to be suitable or adaptable to deal with different input fluids. That is, the mixture may change and be made up of different pairs or combinations of fluids of varying compositions, component densities, and flow rates. External control systems or requirements for frequent adjustment to obtain satisfactory operation are typically needed for those machines having provisions to adapt to varying or differing mixtures or conditions of operation. Besides having only limited effectiveness, such designs are generally complicated to build and operate, making them inefficient or uneconomical.
Some known centrifuges or separators are incapable of operation where input flow and output flows must be maintained at certain pressures. For example, the centrifuges disclosed by U.S. Pat. No. 5,582,724 (Rogers, et al.) have no ability to deliver separated fluids into pressurized lines. Centrifuges of the type illustrated by U.S. Pat. No. 4,525,155 (Nilsson) utilize a paring disk discharge which limits output pressures.
Known centrifuges are not effective if the fluid mixture to be separated contains gas and solid components as well as liquids. That is, centrifuges that are effective in separating two liquids of different densities have no ability for separating and discharging substantial proportions of gas entrained in the input flow. U.S. Pat. No. 5,582,724 (Rogers, et al.) does not provide a means to extract gas from the mixture or from the separated or separating fluids. Further, there is no provision for discharging solids such as sludge, grime, entrained dirt and stone and other physical impurities which tend to build up in the interior of the centrifuge, resulting in a need for periodic cleaning. The centrifuge or U.S. Pat. No. 4,525,155 (Nilsson) does have structure for discharging solids, but the mechanism provided to do so adds greatly to the cost and complexity of the machine.
From the foregoing, it will be appreciated that it would be an advancement in the art to provide a centrifuge of uncomplicated and inexpensive construction, which would automatically separate fluids of varying composition and flow rates and having a wide range of component densities without requiring external control or adjustment of the centrifuge.
It would be a further advancement in the art to provide such a centrifuge that is capable of higher flow capacity for its size than centrifuges in the art. It would also be an advancement in the art to provide a capability to separate fluids at various conditions of fluid pressure, and in the presence of gas and solid components, while also achieving the other advancements mentioned.
SUMMARY OF THE INVENTION
A machine is provided for separating a mixture having a first fluid and a second fluid both of which are preferably liquids. The first fluid and second fluid are of differing densities and, in turn, are susceptible to separation when left standing. The machine has a housing having a central axis. Within the housing is positioned a separation chamber sized to receive and contain a volume of the mixture to be rotated. Fin means are positioned within the separation chamber to rotate therewith. The fin means function to urge the volume and preferably at least one of a first volume of the first fluid and a second volume of the second fluid to rotate with the separation chamber.
Upon separation, the first volume of a first fluid is formed along with the second volume which is of the second fluid. As the mixture rotates, a boundary is formed between the first volume and the second volume at a boundary distance from the central axis.
The machine is provided with an inlet connected to supply the mixture from the exterior to the housing and into the separation chamber. A first weir is connected to the outer wall of the separation chamber and sized to extend toward the central axis and to be spaced from said central axis a first distance selected to be less than the boundary distance to define a first outlet from the separation chamber about the central axis. One of the first fluid and the second fluid passes through the first outlet to exit from the separation chamber.
The machine includes a motor means connected to rotate the separation chamber and the mixture therein. The motor means includes a chamber portion which is positioned proximate the separation chamber in a manner to cause rotation of the separation chamber. The chamber portion is configured to extend away from the central axis a channel distance and is spaced relative to the outer wall to define a channel or passageway for fluid to exit from the separation chamber.
A second weir is connected to one of the chamber portion and the outer wall. The second weir is sized to extend toward the central axis and to be spaced therefrom a second distance selected to be less than the channel distance to define a second outlet from said separation chamber. The other of said first fluid and said second fluid exits from the separation chamber through the second outlet.
Other embodiments include a first fluid chamber and a second fluid chamber positioned to receive the first fluid from the first outlet and the second fluid from the second outlet. Yet, further embodiments include structure for separation and removal of solids and for removal of gas. A preferred embodiment has an overlap distance between the first weir and the channel selected to have the boundary of the first and second fluids therealong.
In a highly preferred alternate embodiment, a second weir volume is formed by the chamber portion. The second weir is in communication with the channel formed by the chamber portion with the outer wall of the separation chamber. The second weir volume is rotata
Cooley Charles E.
Holme Roberts & Owen LLP
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