Patent Document

BACKGROUND OF THE INVENTION 
     The present invention relates to improvements in solids handling for effluent streams containing solids. The typical effluent stream for which the present invention is suitable is the discharge from a kitchen, particularly a restaurant kitchen. Grease traps and oil/grease separators for removal of the oil/grease components from such effluents are known. For example, the Lowe Engineering Company of Lincoln Park, N.J. makes products of this type, as shown in U.S. Pat. Nos. 4,051,024; 4,268,369 and 5,030,357. In addition, Thermaco, Inc. of Asheboro, N.C., manufactures and sells oil/grease removal apparatus under the trademark BIG DIPPER. Exemplary of the patents owned by Thermaco are U.S. Pat. No. 4,235,726 to Shimko, U.S. Pat. No. 5,133,881 to Miller et al., and U.S. Pat. No. 5,360,555 to Batten. The disclosures of these three patents are hereby incorporated by reference. The oil/grease separation devices marketed by Thermaco use various methods for the separation and removal of oil and grease from kitchen effluents, including the gravitational separation techniques and oil-skimming methods shown in the above patents. 
     Typically, oil/grease separators have infeed units including a straining basket into which the solids are directed and trapped to remove them from the flow so they do not interfere with the oil/grease removal process or with subsequent reprocessing of the removed oil/grease. It is up to a restaurant employee to periodically open the unit and remove the strainer basket and dump its contents. These strainers are objectionable to handle because the solids may have strong odors and liquids may drip out of the basket. Since this is an unpleasant chore, sometimes it&#39;s not done. If the strainer basket fills and is not emptied, the grease/oil separator unit may fail and cause the associated plumbing systems to backup. 
     Clearline Systems, Inc. of Asheboro, N.C. has addressed these problems with strainer baskets as shown in U.S. Pat. No. 5,360,555 to the present applicant by providing a grinder/pump to periodically extract accumulated solids from an oil/grease separator device. The disclosure of this patent is hereby incorporated by reference. While this grinder/pump has proved effective to periodically remove separated and accumulated solids without the problems associated with strainer baskets, such grinder/pumps have some limitations. Grinder/pumps require electric power and periodic maintenance or replacement, and their moving parts may become jammed by certain kitchen solids such as bones, silverware, or rubber gloves. If undetected, lodged solids can cause grinder/pump motors to overheat and become damaged. A safety hazard exists when persons insert their hands into the inlets of such grinder/pumps to remove lodged solids without taking proper safety precautions. Such grinder/pumps often must be removed and disassembled for servicing, typically by a manufacturer&#39;s technician, hired plumber or electrician. 
     Accordingly, there is a need in the art for an improvement in devices of this nature to eliminate the problems caused by the presence of strainer baskets and the limitations of grinder/pumps or other similar mechanical pumps. 
     Eductors (also known as “injectors”, “jet pumps”, or “ejectors”) are known and operate by taking advantage of the so-called “venturi effect” wherein introduction of a pressurized motive fluid into a cavity creates a suction in the cavity. This suction in turn draws another fluid or a mixture of another fluid and suspended solids into and through the cavity together with the motive fluid. Eductors are relatively simple and inexpensive compared to mechanical pumps. Eductors have no moving parts to wear or become damaged from use, and are therefore extremely durable in operation. In addition, eductors can be easily sized to suit a wide range of pumping demands. 
     Such eductors have been applied to address a number of needs. For example, U.S. Pat. No. 5,951,878 to Astrom discloses the use of eductors to clean filtrate from a disk filter apparatus. Similarly, U.S. Patent No. 6,083,384 to Al-Ali discloses the use of eductors to retrieve spilled oil. However, eductors have not been used heretofore to address the need for an improved method for removing solids from an oil/grease separation device. 
     SUMMARY OF THE INVENTION 
     The present invention fulfills this need in the art by providing an oil/grease separation apparatus including an eductor system for extraction of accumulated solids. In a typical installation, the oil/grease separator includes a chamber having an inlet section for receiving a liquid flow containing water, oil/grease and gross solids, a downstream section for separating the oil or grease from the effluent, and an outlet section for discharge of the residual water through an outlet. The inlet section is provided with a water jet eductor having an extraction port in the lower portion of the inlet section. Gross solids entering the chamber settle in the inlet section where they are periodically removed by actuating the water jet eductor. The water jet eductor is actuated by opening a water supply valve to provide a flow of pressurized water to the eductor through a water supply line. The suction created by the water jet eductor extracts the accumulated solids from the inlet section through the extraction port. 
     Preferably, the inlet section has a bottom that slopes downwardly toward the extraction port of the water jet eductor to direct accumulated solids toward the extraction port. The apparatus may also include a timer which automatically opens the water supply valve to the eductor for a preset period at a preset time. Alternatively, the water supply valve may be opened by a weight-controlled switch in the inlet section when a preset weight of solids has been collected in the inlet section and closed when the solids have been depleted from the inlet section. The apparatus may also include a grease trap connected to receive the residual water exiting the chamber through the outlet and piping from the water jet eductor that bypasses the grease trap. 
     Preferably, the jet eductor includes an eductor pipe with a first end in communication with the solids extraction port in a lower portion of the inlet section. The second end of the eductor pipe is connected to the outlet section of the chamber. A jet nozzle is provided in the inlet section of the oil/grease separation apparatus and is positioned to direct a jet of water into the first end of the eductor pipe in the inlet section. This jet of water creates a suction in the eductor pipe which causes a mixture of water and solids accumulated in the inlet section to be extracted from the inlet section through the eductor pipe. 
     Alternatively, the jet eductor may include an eductor housing in the inlet section of the chamber having a first opening forming a water injection port, a second opening forming a solids intake port, and a third opening in communication with the solids extraction port. A jet nozzle located inside the housing is connected to the water injection port to receive a supply of pressurized water through a supply line and to direct a jet of water through the discharge port. A discharge pipe connects the third opening in the eductor housing to the outlet section of the chamber. The jet of water creates a suction in the housing and discharge pipe, thereby causing the mixture of water and solids accumulated in the inlet section to be extracted from the inlet section through the discharge pipe. In a preferred arrangement, the eductor housing and discharge pipe are located internal to the chamber. Alternatively, the eductor housing and discharge pipe may be external to the chamber. In this alternative installation, the solids intake port in the housing is connected to a penetration in an outer wall of the chamber in a lower portion of the inlet section. 
     In a typical installation, the oil/grease separation apparatus includes a chamber for receiving a liquid flow containing water, oil/grease and gross solids. The chamber has an inlet section, a downstream section and an outlet in an outlet section. The inlet section is separated from the downstream section by a weir which includes a first wall extending upwardly from the bottom of the chamber to a top above the outlet and a second wall extending downwardly from a height above the liquid level to a submerged level. The weir creates a higher static water level to be maintained in the inlet section than in the downstream section, and facilitates one-way passage of oil/grease from the inlet section to the downstream section. A water jet eductor is provided which has an extraction port in a lower portion of the inlet section for removal of accumulated solids. The inlet section includes an inlet port, a strainer separating the inlet port and the top of the first wall to inhibit the passage of solids to the downstream section, and a bottom which slopes downwardly toward the solids extraction port. An oil/grease separator is located in the downstream section for removing oil/grease from water held in the downstream section. Gross solids entering the chamber settle in the inlet section for periodic removal with some water by the water jet eductor. Oil/grease and water entering the chamber pass to the downstream section where the oil/grease is removed from the water, and the residual water exits the chamber through the outlet section. 
     The invention also provides an oil/grease separation method that includes the efficient removal of accumulated gross solids. The method includes introducing a liquid flow containing water, oil/grease and gross solids into a chamber having an inlet section, a downstream section and an outlet in an outlet section. The gross solids entering the inlet section are permitted to settle in the inlet section where they are periodically removed with some water by actuating a water jet eductor. Oil/grease and water are permitted to pass from the inlet section to a downstream section where the oil/grease is removed from the water. Finally, the residual water is permitted to exit the chamber through the outlet. 
     Preferably, permitting oil/grease and water to pass from the inlet section to the downstream section includes passing the oil/grease and water over a weir that maintains a higher static water level in the inlet section than the downstream section. The method also preferably includes straining gross solids from the liquid flow by a strainer in the inlet section to prevent passage of solids to the downstream section. Desirably, the eductor is sized so that the periodic removal of solids creates a reverse flow of water through the strainer to backwash the strainer. The periodic removal of solids may take place for preset periods at a preset times. For example, this may take place for thirty seconds every thirty minutes. Alternatively, the periodic removal of solids may take place when a preset weight of solids has been collected in the inlet section and end when the solids have been depleted from the inlet section. In a typical installation, the method may include directing the residual water exiting the chamber through the outlet section to a grease trap and directing the solids and water removed from the inlet section during the periodic removal step to bypass the grease trap. 
     The invention may also include a focus plate to concentrate the oil/grease atop the water and a removal means to remove the concentrated oil/grease. The focusing plate may have a ridge aligned with a line between a receiving end and an exit end of the chamber. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be better understood from a reading of the detailed description of the preferred embodiments along with a review of the drawings in which: 
     FIG. 1 is side exterior view of a first embodiment of the invention; 
     FIG. 2 is a sectional view of the embodiment of FIG. 1, taken along lines  2 — 2  and looking in the direction of the arrows; 
     FIG. 3 is a sectional view of the embodiment of FIG. 1, taken along lines  3 — 3  and looking in the direction of the arrows; 
     FIG. 4 is a sectional view of the embodiment of FIG. 2, taken along lines  4 — 4  and looking in the direction of the arrows; 
     FIG. 5 is a sectional view of the embodiment of FIG. 4, taken along lines  5 — 5  and looking in the direction of the arrows; 
     FIG. 6 is a sectional view similar to the view of FIG. 5 showing an alternative piping arrangement; 
     FIG. 7 is a view similar to the view of FIG. 4 of a second embodiment of the invention; 
     FIG. 8 is a sectional view of the embodiment of FIG. 7 taken along lines  8 — 8  and looking in the direction of the arrows; 
     FIG. 9 is an enlarged detail view of the embodiment of FIG. 8; 
     FIG. 10 is a view similar to the view of FIG. 9 showing an alternative arrangement for the eductor housing; 
     FIG. 11 is a side view and partial section view of a third embodiment of the invention having an eductor system external to the separator; 
     FIG. 12 is a plan view of the embodiment of FIG. 11; 
     FIG. 13 is an end view of the inlet and of the embodiment of FIGS. 11 and 12; 
     FIG. 14 is a side sectional view of a fourth embodiment taken along line  14 — 14  in FIG. 15; 
     FIG. 15 is a top view of the embodiment of FIG. 14 shown with the focusing plate assembly removed; 
     FIG. 16 is a sectional view of the fourth embodiment taken along line  16 — 16  in FIG. 15; and 
     FIG. 17 is a sectional view of the fourth embodiment taken along line  17 — 17  in FIG.  15 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention provides an oil/grease separator  10  including a water jet eductor for extraction and disposal of solids. As seen in FIGS. 1-5, a first embodiment includes a housing  12  having an inlet  14  and an outlet  16 . As best seen in FIG. 4, the inlet  14 , which can be connected to a discharge from a kitchen sink or the like, deposits kitchen effluent into an inlet chamber  28 . The downstream edge of the inlet  28  is defined by a weir  30  upstanding from the bottom portion of the housing  12 . A plate  32  extending down from the upper portion of the housing  12  cooperates with the weir  30  to provide a downwardly extending passage into a quiescent region  22 . In the quiescent region  22 , oil/grease and water reside for a long enough period of time so that the oil/grease floats to the top of the water. The downstream edge of the quiescent region  22  is defined by a baffle  34  extending downwardly from the housing  12 . Water passes from the quiescent region  22  to an outlet chamber  24  by passing under the lower edge of the baffle  34 . The water is then discharged from the outlet chamber  24  through the outlet  16 . 
     The floating oil/grease can be removed in conventional fashion using any desired oil/grease separator such as those shown in the above-mentioned patents. For example, an oil-grease skimming device  38  may be provided to collect the floating oil/grease from the surface of the water. Alternatively, oil/grease removal methods or apparatus as disclosed in co-pending U.S. patent application Ser. No. 09/439,900 filed Nov. 12, 1999, or U.S. patent application Ser. No. 09/439,542 filed on Nov. 12, 1999, the entire disclosures of which are hereby incorporated by reference, may be used. 
     As can be best seen in FIG. 4, the inlet chamber  28  is provided with a downwardly extending strainer screen  46  attached to the housing  12  and the weir  30 . Alternatively, a wedge-wire strainer basket may be used to prevent solids from passing out of the inlet chamber. As shown in FIG. 3, the inlet chamber  28  is provided with a sloping bottom  26 . At the lower part of the sloping bottom is solids extraction port  44  in the weir  30 . As best seen in FIG. 4, an eductor pipe  36  communicates with the solids extraction port  44  and extends to the outlet  16 . A water jet nozzle  40  in the inlet chamber  28  is positioned to direct a jet of water supplied through a water supply line  18  into the solids extraction port  44 . The supply of water to the nozzle  40  is regulated by a water supply valve  20  in the water supply line  18 . 
     In operation, oil/grease and solids and water pass into the inlet chamber  28  from the inlet  14 . The oil/grease and water pass through the screen  46 , over the weir  30 , and into the quiescent region  22 . However, solids are prevented from passing out of the inlet chamber  28  by the screen  46  and settle atop the sloping bottom  26  in the region of the solids extraction port  44 . The accumulated solids are periodically removed from the inlet chamber by opening the water supply valve  18  to direct a jet of water from the nozzle  40  into the solids extraction port  44 . The jet of water creates a suction in the eductor pipe  36  at the solids extraction port  44 . The solids are thereby drawn from the inlet chamber  28  into the eductor pipe  36  and pass through the eductor pipe  36  to the outlet  16 . The solids then pass together with the residual water exiting the outlet  16  to a grease trap. Alternatively, the solids may be directed to independent piping  152  connected to the eductor pipe  136  to bypass the grease trap, as shown in FIG.  6 . 
     As discussed above, the water supply valve  20  is opened to supply water to the nozzle  40  to activate the eductor system to periodically extract the accumulated solids from the oil/grease separator  10 . In the embodiment shown in FIG. 5, a timer  52  is used to open the water supply valve  20  at a preset time for a preset period of time to discharge whatever solids may be collected. In an alternate embodiment shown in FIG. 3, a weight-activated micro switch  42  at the bottom of the inlet chamber  28  is used to sense a threshold weight of solids and to open the supply valve  40  to activate the eductor system. Once the solids are substantially depleted from the inlet chamber, the micro switch  42  closes the supply valve  20  to shut off the eductor system. In addition, other control mechanisms for the water supply valve may be substituted, as will be apparent to those skilled in the art. Also, the timer or switch can be used to start a pump or other means for inducing the liquid flow for the eductor. 
     A second embodiment of the invention is shown in FIGS. 7-9. In this embodiment, an eductor housing  252  is provided at the bottom of the inlet chamber  28  at the base of the sloping bottom  26 . As best seen in the enlarged sectional view of FIG. 9, the eductor housing  252  has a water injection port  256 , a solids discharge port  260 , and a solids intake port  258 . As will be appreciated by those of ordinary skill in the art, the eductor housing  252  and its components may have a variety of configurations other than as depicted in the drawings. A water jet nozzle  240  is located inside the eductor housing  252  and is connected to a water supply line  218 . The nozzle  240  is positioned to direct a jet of water through the discharge port  260 . Alternatively, multiple nozzles  240  may be used in the eductor housing  252  (not shown). The solids discharge port  260  is connected to a discharge pipe  236  which extends either to the outlet  16  of the separator  10  or to independent piping for discharge of the solids. In operation, water is supplied to the nozzle  240  which directs a jet of water through the discharge port  260 . A suction is created in the inside the eductor housing  252  which draws solids from the inlet chamber  28  into the housing  252 . The solids then pass with water out of the housing  252  through the discharge port  260  and through the discharge pipe  236  for disposal. 
     As shown in FIG. 10, the eductor housing  352  may be external to the oil/grease separator housing  12 . The solids intake port  358  of the eductor housing  352  communicates with a solids outlet  350  in the housing  12  at the bottom of the inlet chamber  28 . A water supply line  318  supplies water to a water jet nozzle  340  inside the eductor housing  352 . A solids discharge pipe  336  connects the solids discharge port  360  in the housing  354  either to the separator outlet  16  or to independent piping. In operation, a jet of water from the nozzle  340  creates a suction in the eductor housing  352 . This suction causes the solids in the inlet chamber  28  to be extracted from the housing  12  through the solids outlet  350  and the discharge pipe  336 . 
     A third embodiment is shown in FIGS. 11-13, wherein a solids extraction chamber  470  extends from one side of the housing  12 . A solids extraction chamber  470  communicates with the inlet section  428  through a window  472 . An eductor nozzle  474  has one end connected to an opening in the top of the solids extraction chamber  470  and a second end connected to the outlet  416  by a discharge pipe  436 . As best seen in the partial section of FIG. 11, a small-diameter tube  476  extends through a wall of the eductor nozzle  474  to direct a jet of water into the discharge pipe  436 . When a water supply valve  420  is opened, a jet of water is injected into the discharge pipe  436 , thereby causing solids with water to be drawn from the inlet section  428  into the solids extraction chamber  470  through the nozzle  474  and to the outlet  416  through the discharge pipe  436 . Alternatively, the solids can be directed to alternate piping for disposal. 
     A fourth embodiment is shown in FIGS. 14-17. A housing  512  has an inlet  514  and an outlet  516 . Influent passes through the inlet  514  and into an inlet chamber  528 . Heavy solids in the influent settle downwardly in the inlet chamber  528 . A grille  545  prevents large solids such as flatware or bones from passing to a lower portion of the inlet chamber  528 . Smaller heavy solids pass through the grille  545 , and are directed to a solids collection zone  527  by a sloping bottom  526 . As best seen in FIGS. 15 and 17, water, oil/grease, and fine floating solids pass from the inlet chamber  528  to a quiescent region  522  through slots  546  and  547 . A baffle  548  may be provided in the inlet chamber  528  to prevent the momentum of incoming effluent from causing undue water passage through slots  547 . 
     As best seen in FIGS. 14 and 15, an eductor tube  536  extends from the solids collection zone  527  to an outlet  536 . A water injection tube  576  extends into the eductor tube  536  as shown in FIG.  15 . As water is injected from tube  576  into the eductor tube  536 , accumulated solids are extracted from the collection zone  527  and transferred out through the eductor tube  536  to an outlet  537  for disposal. 
     As seen best in FIGS. 14 and 16, a focusing plate assembly  590  is provided in an upper portion of the housing  512 . Such focusing plates are disclosed in co-pending U.S. patent application Ser. No. 09/439,900 which was incorporated by reference above. As seen best in FIG. 16, the bottom surface of the plate  590  causes oil/grease floating near the top of the quiescent region  522  to concentrate along a central region of the housing. The focusing plate  590  of this embodiment has a peak or ridge  591  that extends along the inlet-outlet axis of the apparatus. This is a presently preferred design to enable manufacturing flexibility. Larger or smaller size units can be made by making the focusing plate longer or shorter without changing the shape of the plate. An oil/grease extraction tube  538  extends upward in the quiescent region to a height just below the static water level in the peak or ridge  591  of the focusing plate  590 . Floating oil/grease is extracted through the tube  538  by activating a fluid motivated pump  580 , which causes the oil/grease to pass into the tube  538  and out through an exit port  595 . Fluid motivated pumps are disclosed in co-pending U.S. patent application Ser. No. 09/567,778, filed May 9, 2000, which is hereby incorporated by reference. 
     As will be appreciated, other eductor designs other than as specifically depicted and described may be substituted. 
     As will be apparent to those of ordinary skill in the art, the invention can be adapted to various types of oil/grease separators having solids accumulation capability and is not limited to the specific embodiments discussed above. Those of ordinary skill in the art will also appreciate that the invention could be carried out in other various forms, all of which are deemed to be within the scope of the appended claims.

Technology Category: 7