Abstract:
An oil-water and oil emulsion separation system using a plurality of transport vessels as the separation tanks. The containers or tanks are arranged in series with sludge or oil removed first and thereafter remaining oil is removed and finally a relatively pure aqueous solution is returned to the system. The unit is useful with parts washers or any apparatus with which water is contaminated by free oil or sludge. A floating skimmer is placed in the user&#39;s sump and a vacuum draws this into a series of containers in which it is processed and in which sludge and oil are successively separated. A positive displacement pump is used. A manifold having vacuum relief valves for at least one container is also provided. In one embodiment, flow restrictors are placed in at least one manifold.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates generally to oil-water and emulsion separation systems, and more particularly, to a system which includes components that are placed in an oil-contaminated water-based system and arranged in series with sludge or oil removed first, and then secondarily, oil, oil removal, and finally a relatively pure aqueous solution results, and this solution is returned to the system. The unit is useful with parts washers and other forms of apparatus which use water and are contaminated by free oil as at least a part of their process fluids. Preferably, the system conveniently uses the same transport containers in which oil, soap or other component is supplied as an integral part of the removal system. 
     The term “washing fluid” is intended to be an all-inclusive term, which includes water, any number of emulsifying agents, cutting oils, lube oils, way oils and lubricants of various kinds, additives, as well as impurities created by cutting, drilling or other machining operations, including grinding or abrasive metal reduction. The term also includes fluids not strictly used for washing, but which are nonetheless subject to oil/water separation, such as those used in aqueous-based parts washers. For purposes of illustration, however, the description herein is primarily directed to those creating sludge or oil to be separated from the aqueous component. 
     In the preferred form, a floating skimmer is placed in the user&#39;s machine sump and this is able to transport oil and contaminant-laden fluid to the treating elements. The remainder of the elements making up the system are preferably drums or transport vessels, together with hoses, manifolds, vacuum reliefs and other components. The servicing of the apparatus is carried out by a contractor who specializes in removing sludge and/or oil from the premises. 
     In the preferred form, the containers are removable and replaceable, and the components which are used in processing the fluids are reusable. 
     In one embodiment, the system contains a floating contaminant removal device, termed a “skimmer”, which has an inlet lying just beneath the surface of the liquid. In another embodiment, there is a dip tube or pick up which is dispensed in the body of the washing fluid bath itself. The liquid itself is continuously recirculated by means of a positive displacement pump and passes through one or more drums. The sludge may collect at the bottom of the drum, and the oils and other lighter-than-water contaminants are picked up from the top surface of the washing fluid in this embodiment by a floating skimmer and directed via suitable tubing through an oil trap, and finally, through a positive displacement pump before being returned in a substantially free of non-emulsified oil condition to the machine bath or other source of liquid. The oil trap, where present, removes tramp oil, floating solids, and other non-emulsified, lighter-than-water impurities, and in some cases, heavier than water contaminants which are trapped or otherwise contained in the oil or emulsified phases. 
     The system is designed to clean and maintain a variety of liquid systems which primarily use water, but also contain, in most cases in emulsion form, a lubricant for the machine, and various surface active gents which maintain the oil-water emulsion and prevent corrosion. There may be other components whose identity will vary somewhat with the application and the details of whose composition is not particularly relevant to the present invention. 
     An advantage of one form of the present invention is that it gives an outside contractor or supplier the ability periodically to service the apparatus without disturbing the principal machine, or compromising its operation. Thus, service may be performed by removing the sludge or oil from the trap or separator. This is accomplished merely by disconnecting the electrical power supply to the pump and disconnecting the fluid conduits leading to the various sludge or oil traps. In this way, the customer&#39;s principal machine need undergo no significant down time, or no down time at all. Most or all of the maintenance can be performed without stopping the principal machine. 
     The skimmer and the hose connecting it to the remainder of the apparatus may be simply serviced or replaced. This is because the skimmer preferably has no moving parts and preferably only one adjustable part. The height of the inlet may be adjusted simply by turning the threaded insert to raise or lower the skimmer inlet and thus to adjust the skim gap. 
     The sludge trap when operated without an oil trap preferably consists of a drum of the type used to transport liquids, namely, a 16-, 30-, or 55-gallon drum. The inlet at the source lies on or near the bottom of the customer sump in one embodiment. The hose leads to the sludge trap and the inlet to the drum is a fraction of the drum depth. The outlet connects to a fitting with a vacuum relief port. The liquid is advanced by a positive displacement pump, and the outlet of the pump connects with the customer sump to return the sludge-free fluid to the sump. 
     The construction of an oil trap according to the invention is such that a somewhat non-emulsified oil-water mixture enters the trap at a manifold and the liquid phase is directed downwardly well past the vertical middle of the trap. As the oil coalesces, it floats to the top and forms several layers. An air layer is at the top, an oil layer is next, then an emulsified oil-and-water layer, and finally, a lowermost water layer is formed. Accordingly, the water phase lies adjacent the bottom of the oil trap housing. The return tube extends toward the bottom of the vessel and has a connection at its upper end to the positive displacement pump; it is also in communication with the air in the air-tight manifold. The oil accumulates below a bleed hole in the manifold portion of the oil trap. The water passes from near the bottom to the return tube and hence is substantially oil-free. A strainer screen and a filter may be introduced between the trap and pump to protect the positive displacement pump from harmful impurities or components on this portion of the apparatus. 
     The positive displacement pump is preferably a bellows-, oscillating-, or diaphragm-type pump which functions at various flow rates but efficiencies are determined by the size of the drum used. A bellows-, oscillating-, or diaphragm-type pump is selected because of its self-priming capability. Preferably, the rate of the flow of the oil pump is selected so as to allow an appropriate residence time for oil and water separation within the oil trap. Additionally, a positive displacement pump provides low shear forces. 
     Another embodiment uses two identical oil trap drums cascaded so as to empty a more clear fluid from the first to the second. The two drums each include a manifold with an inlet, an outlet and a bleed opening, and the second one includes a vacuum break. Only one positive displacement pump is used, preferably just past the outlet of the second drum. 
     Still another embodiment cascades the sludge trap with an oil trap, with the oil trap having the bleed opening and the vacuum relief as well as the same positive displacement pump. This arrangement may have a skimmer or a bottom pick up, or both. Other arrangements may be found suitable. 
     The vacuum opening on the manifold may permit vacuum to be broken so as to protect the pump from becoming clogged or especially, collapsing one or more drums in operation. 
     In view of the failure of the prior art to provide a simple, integrated cost-effective system for liquids, including sludge and oil separators, that uses transport vessels as a part thereof, it is an object of the present invention to provide such an integrated or independent oil and/or sludge trap system. 
     It is another object of the invention to provide a sludge trap system, which, except for the pick up and discharge elements, lies entirely outside the apparatus with which it is used, and hence is functionally independent of such apparatus. 
     Yet another object of the invention is to provide a system which will both pick up sludge and oil and separate them from water. 
     An additional object of the invention is to provide a pump which is operable by ordinary, plug-in low voltage shop current available in many locations. 
     A still further object of the invention is to provide an apparatus wherein the periodic servicing may be carried out in a matter of minutes, which is due to the nature and arrangement of components. 
     Another object of the invention is to provide an oil trap or separator which may be serviced and/or removed and replaced by a service organization without materially disturbing the operation of the customer&#39;s principal system/machine. 
     An additional object of the invention is to provide an oil and/or sludge trap with a vacuum relief to avoid damage to these parts. 
     Still another object of the invention is to provide a modular oil trap or sludge trap which may be used in cascade form in any order or quantity to meet the specific applications, volumes, and separation requirements of the customers. 
     Another object of the invention is to provide a bleed hole in the manifold for allowing air to pass through the system without further emulsifying the mixture and for maintaining the level of liquid in the drum(s). 
     A still further object of the invention is to provide a system which uses standard transport vessels such as drums as the sludge—or oil traps and hence require very few special parts to make a complete apparatus. 
     SUMMARY OF THE INVENTION 
     The present invention achieves its objects and others by providing a sludge trap and oil trap with drums, manifolds, bleed openings and vacuum relief as well as a positive displacement pump, all adapted to work with or without a skimmer for picking up floating and submerged oil and sludge. 
     The manner in which the foregoing objects and advantages are achieved in practice will become more apparent when considered in connection with the detailed description of the preferred embodiments of the invention set forth by way of example and shown in the accompanying drawings wherein like reference numerals indicate corresponding parts throughout. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a view, largely diagrammatic, showing the major elements of one embodiment of the sludge trap of the present invention; 
     FIG. 2 is a view, largely diagrammatic, of the major elements of the invention and similar to FIG. 1 except that it also includes an oil trap in series with the sludge trap; 
     FIG. 2A is an enlarged view of portions of the manifold containing the “pucks” or flow restrictors which are used to help coalesce the liquid and break the foam; 
     FIG. 3 is a diagrammatic view similar to FIG. 2 except that it also uses a skimmer as a pick up from the customer sump; and, 
     FIG. 4 is a diagrammatic view showing two cascaded oil traps, showing details of an interconnect system including a bleed hole in each dip tube and a vacuum relief in the downstream manifold. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Although the present invention may be embodied in a number of different forms and the elements may be arranged in different configurations, several preferred embodiments of the invention are shown. Other embodiments or arrangements of components will also be apparent to those skilled in the art, and such changes or modifications may be made without departing from the scope of the invention. 
     Referring now to the drawings in greater detail, there is shown in FIG. 1 a schematic view of one of the simple forms of the invention, namely, a sludge trap. In this embodiment, there are several important components. The system is generally designated  20 , and it includes a customer sump  22 , a sludge trap  24 , an optional filter  26  and a positive displacement pump  58   
     The sump  22  belongs to the customer, and contains basically water, but also includes sludge components, such as grease washed from machine parts, metal shavings, filings or other residue from machining operations. It may also include tramp oil, soapy and/or other aqueous residue from a parts washer, coolants from a machining center or the like. The pick up of this residue is made from a scavengers  30  which picks up bottom sludge components as well as suspended solids of various kinds. From the scavenger  30 , the liquids are fed through a hose  32  to an inlet fitting  34  having an outlet end  36  lying near the top of the sludge trap  24  in the form of a barrel  38 . The fitting  34  passes through an opening  40  in the top  42  of the barrel  38  which is air- and liquid-tight. 
     Another air- and liquid-tight passage  44  is provided for the outlet fitting  46  which is connected to a hose  48  leading to the optional filter  26 . Very importantly, the fitting  46  includes a vacuum relief passage  50  which preferably is set at 4-20 psi, preferably 10-15 psi. 
     The optional filter  26  contains a pair of small fittings  52 ,  54 , the outlet fitting  54  of which is connected to a hose  56  which in turn is connected to a positive displacement pump  58 . The pump outlet  60  passes to a return hose  62  which then has an outlet  64  in the customer sump  22 . 
     The positive displacement pump typically operates at about up to 5-15 psi, and draws fluid from the sump  22 , including bottom sediment and other sludge-like constituents and causes them to pass through the hose  32  to the inlet fitting. From here, the sludge falls to the bottom of the trap  38 , while the liquid phase enters the fitting  34  under the influence of the vacuum created by the pump  58 . As long as the pump can pull a partial vacuum, liquid flows through the lines  48 ,  56 , while liquid and sludge pass through line  32 . The sludge falls out and eventually fills the barrel  38  which may then be emptied in due time. 
     In the event the vacuum level surpasses the setting on the vacuum relief valve  50 , the valve merely admits air to prevent collapse of the lines, and most importantly, the drum  38 . 
     The hoses, except for those upstream of the sludge or oil trap, are preferably color-coded, and will withstand at least 10 psi and preferably much more. The filter  26  is also rigid and typically capable of withstanding much more than 50 psi. The positive displacement pump  58  can draw vacuum of from 5 to 14 psi. It is preferably of the diaphragm-, oscillating-, or bellows-type, but may be a piston type or other style of pump. it is preferably driven by an electric motor, (not shown), but may be air-operated if desired. 
     The drum, as pointed out above, is a 16-, 30- or 55-gallon drum. This is a feature of the invention which is important, although not absolutely necessary. Thus, a cover with an inlet and an outlet is all that needs to be provided in addition to the selected vessel. All the working elements of the system are extended to the drum  38 , but the drum  38  makes up an important portion of the device; the drum  38  may be removed and replaced since it is a commodity and not necessarily associated with any particular set of components. 
     Referring now to FIG. 2, another embodiment is shown in which a drum  138  serves as a sludge trap. The drum  138  is shown to be associated with an oil trap generally designated  70  in cascaded relation, that is, the outlet fitting  46  and hose  48  are directed into an inlet fitting  72  of the oil trap  70 . More particularly, the fitting  72  includes a dip tube  74  that extends well below the level  76  of liquid in the drum  78 . In use, there is a certain amount of air, then an oil layer shown at  80 , a layer  82  of emulsified oil and water, and finally, toward the bottom, a water layer  84 . 
     The dip tube  74  includes, near but spaced slightly below the cover  86 , a bleed hole  88 . The dip tube  74  is fit with an air- and liquid-tight seal  90  to the cover  86 . 
     A second component of the oil trap  70  is a second or outlet dip tube  92  which typically extends well into the water layer  84  in the drum  78 . There is a seal  94  between the second dip tube  92  and the drum cover  86 , and of course the cover is tightly sealed to the drum  78 . A manifold leg  96  extends between these fittings  72 ,  98  and this equalizes the suction or vacuum between these components and permits air to bypass the liquid phase without creating any additional emulsion. In addition, a vacuum relief  100  is provided in one leg of the manifold to prevent collapse of the components. 
     Besides these elements, there is also provided an intermediate hose  148 , inlet and outlet fittings  152 ,  154  and an optional filter  126 . Another line  156  leads to a positive displacement pump  158 , having a fitting  160  connected to the return hose  162 . The other elements of the sludge trap such as the customer sump  122 , the inlet hose  132 , the inlet fitting  134 , the drum  138  and the outlet fitting as well as the connection  148  are the same as their counterparts in FIG.  1 . 
     This embodiment is useful where the recirculated liquid includes both substantial amounts of sludge and heavier-than-water impurities and oil/oil and water emulsion. The sludge accumulates in the sludge trap  124 , and the oil and water are passed to the oil trap  70 . Here the dip tubes extend well below the levels of oil and oil/water emulsion, leaving the water to pass back to the customer sump  122 . Again, if the vacuum level becomes excessive, the relief valve  100  is opened before the drums or the hoses collapse. Only the vacuum relief  100  need be provided, since the drums  78 ,  124  are in series. 
     Because the washing fluid or emulsion, etc., as processed generally includes surfactants of various kinds, the movement through the drum(s) fittings and dip tubes creates a great deal of foam which is a drawback to processing. Consequently, as shown in FIG.  2  and shown enlarged in FIG. 2A, each of the manifolds includes at least one and preferably two flow restrictors or “pucks”  99 ,  101  in its vertical legs  98 ,  100 . These have the effect of breaking the foam, even relatively stable foam, and allowing it to coalesce in the legs  98 , 100 , and run down toward the fittings  90 ,  94 . The pucks in the form shown have a round, outside diameter  103 , a flat body surface  105  and a small center opening  107  therein. Other configurations may be used. 
     Referring now to FIG. 3, another embodiment is shown which is very similar to the embodiment of FIG.  2 . In fact, the only difference in these embodiments is the manner in which the liquid is picked up from the customer sump  222 . This is accomplished by a skimmer generally designated  240 . This skimmer floats atop the liquid  242  and feeds the inlet hose  232 . In the alternative, other adjustable type skimmers of the type described in U.S. patent application Ser. Nos. 09/470,872 and 09/649,832 U.S. Pat. No. 6,322,694 may be used. 
     In operation, the apparatus operates like the others; the only difference is the manner and type of impurities being picked up. In some cases, there can be amounts of sludge picked up that are still collected with a skimmer; these are emulsified in use, but coalesce into sludge with the passage of time. 
     Referring now to FIG. 4, still another embodiment is shown. In this embodiment, there are two drums  324 ,  378  cascaded or placed in series. The pair are fitted with a single skimmer  340  of the same type as shown in FIG.  3 . The skimmer  340  floats atop the liquid level  342  in the customer sump  322 , and has an inlet  344  between the balls  346  of the skimmer. The inlet is connected to the inlet hose  332 , which in turn is connected to one leg  335  of one manifold generally designated  333 . 
     The two traps  324 ,  378  are connected in series with one another. The two manifolds  333 ,  396  each have two dip tubes  351 ,  353  and  374 ,  392 . One dip tube  351 ,  374  of each pair has a bleed opening  373 ,  308 , and all four tubes are sealed respectively to the two covers  353 ,  386 . Only one vacuum relief  400  is required since the drums are connected in series. 
     The final filter  351  and the positive displacement pump  358  are the same as their counterparts in the earlier figures. In operation, the two-drum separator separates oil and water with a slight difference. The first drum  324  can operate until it is completely filled with oil, whereupon the second drum  378  operates. However, the second drum may operate before the first drum is filled, and in this case, it acts to improve or add to the efficiency of separation. 
     As illustrated, the pump is shown to draw or pull in suction, although conceivably, it could be used to push the liquids through the drums. Such arrangement would not be preferred, however. 
     It will thus be seen that the present invention provides a simplified, integrated system for removing floating and suspended contaminants from a customer machine, all requiring no down time for service or replacement, having a number of advantages and characteristics including those expressly pointed out here, and others which are inherent in the invention. An illustrative embodiment of the product of the invention having been shown and described, it is anticipated that variations to the described form of apparatus will occur to those skilled in the art and that such modifications and changes may be made without departing from the spirit of the invention, or the scope of the appended claims.