Fluid handling – Systems – Tank with internally extending flow guide – pipe or conduit
Reexamination Certificate
1999-12-14
2001-05-22
Lee, Kevin (Department: 3753)
Fluid handling
Systems
Tank with internally extending flow guide, pipe or conduit
C210S488000, C210S521000, C210S532200
Reexamination Certificate
active
06234200
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to liquid flow control and is especially applicable to the controlling of flow towards a discharge line in a separator vessel, such as a grease trap. The vessel is intended to permit separation of insoluble components from a liquid and typically the insoluble components will comprise buoyant components (such as fats and grease) and non-buoyant components (such as heavy solid particles).
The object is to control flow so that only clear liquid drawn from an intermediate level of the materials in the vessel is discharged.
BACKGROUND TO THE INVENTION
A conventional approach to the problem as applied to such installations as grease traps and septic tanks is to provide sufficient volume and separation of inlet and outlets with appropriate baffles to have sufficient holding time of the liquid and insoluble materials for separation to occur naturally. However, this process is not entirely reliable and contamination of e.g. sewer lines or absorption trenches can occur. This is especially the case where it is necessary or simply desirable to have a vessel of relatively small dimensions and a frequent problem occurs where there are major surges of flow into the vessel. Surges can produce turbulence and the rapid increase of liquid in the vessel displaces a corresponding volume rapidly through the discharge line. Thus entrainment of both buoyant and non-buoyant contaminants can all too easily occur.
For exemplification only the invention will be described and with reference to grease traps but it is to be understood the invention is not so restricted and applies to all similar installations.
Generally, commercial establishments such as restaurants are obliged to install and maintain a grease trap for waste water and at regular intervals the grease trap will need to be pumped free of major build ups of both buoyant and non-buoyant contaminants. Filter type units have been extensively employed to try and control unintended discharge of contaminants into the waste water and such filter units have been positioned around the normal liquid level and generally have been of a removable cartridge type. In a typical restaurant type facility a grease trap must be pumped to remove contaminants every few weeks and the contractor should also change the cartridge type filter. However, the expense of grease trap servicing is significant and proprietors will be tempted to remove filters to ensure longer time between serving. If the filter is not regularly serviced, then there is likely to become clogging due to greases at the surface of the liquid in the vessel and, especially under the surge conditions which frequently arise, waste water may flood back into the premises.
One form of such filter comprises a rigid collection of shaped plates which have apertures between the plates to provide the filter structure. The plates are disposed horizontally and the cartridge has a vertical axis. An example of such as filter is that of U.S. Pat. No. 4,710,295 (Zabel).
SUMMARY OF THE INVENTION
The present invention is based on a different approach to the processing e.g. waste water and is based on the concept of providing a control device positioned at an intermediate level in a waste water tank to protect a discharge line and to facilitate separation of both buoyant and non-buoyant contaminants in the inlet water even under demanding surge conditions. The invention also extends to analogous applications for separation of other contaminated liquids.
The present invention manifests itself in various aspects including a fluid flow control device, a liquid processing system and a method of processing contaminated liquids.
According to a first aspect of the present invention, there is provided apparatus for controlling liquid flow from a holding vessel to a discharge line wherein insoluble material received into the vessel with liquid is intended to be retained in the vessel, the apparatus having:
(i) wall means within which an interior cavity is defined for connection to the discharge line at a location below the surface of liquid in the vessel,
(ii) apertures spaced along the wall means for admitting liquid from the vessel into the interior cavity,
(iii) wall elements between the apertures providing inclined ramps which confront one another and between which pockets are provided for receiving the liquid in a relatively quiescent state whereby movement upwardly of buoyant components of the insoluble material towards the top of the vessel occurs with deflection of the buoyant components by superior ones of said ramps, and movement downwardly of non-buoyat components of the insoluble material towards the bottom of the vessel occurs with deflection by inferior ones of the ramps, and
(iv) the apertures being configured and dimensioned to restrict and control flow of liquid into the interior cavity whereby under surges of flow into the vessel there is substantial resistance to liquid discharge through the discharge line.
Preferably the apparatus comprises a multiplicity of plate elements interconnected to form the body of the apparatus, each plate element comprising a disk having a central aperture and a serpentine continuous wall structure extending from the disk and providing the confronting ramps, spacing means being provided so that the edge of each inclined ramps is closely spaced from the disk of the adjacent plate element.
Preferably the apparatus is adapted to have a horizontal axis around which the interior cavity is defined, several confronting pairs of ramps are provided on each side of the apparatus and each aperture is in the form of a slit extending substantially entirely around the apparatus.
The invention extends to a waste water treatment apparatus such as a grease trap and having an inlet at a first upper region of the vessel and an outlet at a spaced second upper region for the vessel, the outlet having a pipe extending downwardly into a central region of the vessel and connected to a liquid flow control apparatus as described in any one of the forms above such that buoyant contaminant material floats to the surface of the liquid in the vessel and solid contaminant material sinks to the bottom of the vessel for periodic cleaning by pump out and substantially clarified liquid migrates from the central region of the vessel into the interior cavity and then to the discharge line.
Further inventive and novel features may be incorporated in embodiments of the invention as will be described below with reference to the drawings It will be appreciated that particularly with preferred embodiments an efficient control device can be manufactured and which is essentially of a self cleaning character, thereby permitting the device to be installed in a central region of the grease trap and there is no requirement for periodic removal or cleaning in ordinary use. The device can be manufactured in a robust and durable form and its operation can ensure a high level of separation of contaminants from waste water, thereby protecting the environment while obviating expensive regular servicing costs required for prior art filter type devices.
Embodiments of the invention lend themselves to retrofitting to existing grease traps or other liquid pre-treatment vessels and it is believed that compared to prior art proposals a substantial increase in efficiency can be achieved
It is believed that prior art pre-treatment separator vessels such as grease traps have been relatively inefficient and this is especially the case when applied to modern installations liable to high surges, e.g. due to dishwasher discharges and the general increase in higher water consumption due to more thorough and cleaning operations that are often required in modern commercial operations to comply with health regulations.
REFERENCES:
patent: 4710295 (1987-12-01), Zabel
patent: 5101849 (1992-04-01), Richard
Kelly Bauersfeld Lowry & Kelley LLP
Lee Kevin
LandOfFree
Flow control devices does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Flow control devices, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Flow control devices will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2510033