The present disclosure generally relates to fluid separation and filtering devices, and more particularly to apparatus and methods for separating floating oil and floating and suspended solids from an aqueous fluid.
Aqueous fluids are used in a variety of applications and for a number of different purposes. For example, aqueous fluids are often used to clean, cool, and suppress bacterial growth in various types of equipment or parts used in machine shops, automotive repair facilities, and other locations. During use, the aqueous fluid may pick up contaminants such as floating oil, sludge, and floating or suspended solids (such as metal shavings), from the equipment and parts. Such contaminants may clog the circulation pump, foster anaerobic or aerobic bacterial growth, and contaminate materials placed in the bath. The contaminants may cause additional problems in certain applications, such as when the aqueous fluid is a machining coolant, since the contaminants may be discharged from the machine tool onto the workpiece. The transfer of contaminants to the workpiece may cause imperfections in the surfaces of the workpiece, reducing the machining quality and increasing the scrap rate.
Various separation and/or filtering apparatus are known for removing oil, sludge, and debris from the aqueous fluid so that the aqueous fluid may be reused. Such apparatus typically draws the aqueous fluid from a reservoir, such as a sump, through a floating skimmer. The oil, sludge, and debris is then removed during various separating and filtering stages, after which clean aqueous fluid is then returned to the reservoir. During the process, the aqueous fluid and contaminants may be pumped into a drum. The aqueous fluid, oil, sludge, and other contaminants have different densities and therefore separate into different layers within the tank, with the oil typically rising to the top of the tank. By drawing aqueous fluid from a bottom of the tank, the oil and other contaminants remain in the tank. Another filter stage may be used to remove debris or other contaminants from the relatively clean aqueous fluid drawn from the tank bottom.
Conventional separation apparatus suffer from several drawbacks. First, the pumps used in typical separation apparatus impose excessive space requirements or introduce performance inefficiencies. Some prior designs include a submersible pump disposed in the sump. This approach requires the sump to be sufficiently large to accommodate the pump and therefore imposes specific space requirements for the system. Additionally, operation of the pump within the sump will agitate the aqueous fluid passing through the pump, thereby more thoroughly mixing the contaminants with the aqueous fluid and making separation more difficult. Other designs that locate the pump outside of the sump impose other space requirements and generally suffer from decreased separation performance. Second, conventional separation apparatus also have clogging problems at the inlet that cause performance and maintenance issues. Third, the location of certain components outside of the barrel in conventional separation apparatus makes them more difficult to ship and service. The subject matter specified in the appended claims may address these and other issues with previously known separation apparatus.
In accordance with one aspect of the disclosure, an apparatus for separating oil and debris from an aqueous fluid disposed in a bath is provided that includes a separator assembly including a tank defining an interior chamber, and a separator coupled to the tank, the separator including an inlet in fluid communication with the bath and an outlet. A rotary positive displacement pump has a pump inlet in fluid communication with the separator outlet and a pump outlet in fluid communication with the bath.
In another aspect of the disclosure that may be combined with any of these aspects, the rotary positive displacement pump comprises a rotary vane pump.
In another aspect of the disclosure that may be combined with any of these aspects, the rotary vane pump includes vanes and stators formed of a carbon material.
In another aspect of the disclosure that may be combined with any of these aspects, the rotary vane pump includes vanes and stators having an exterior surface formed of PEEK.
In another aspect of the disclosure that may be combined with any of these aspects, the rotary vane pump comprises one of a magnetic induction drive and a direct drive.
In another aspect of the disclosure that may be combined with any of these aspects, the aqueous fluid comprises a machining coolant.
In another aspect of the disclosure that may be combined with any of these aspects, the separator tube is disposed entirely within the tank.
In another aspect of the disclosure that may be combined with any of these aspects, a discharge valve fluidly communicates with the tank interior chamber at a height associated with an oil layer in the tank.
In another aspect of the disclosure that may be combined with any of these aspects, the filter element comprises a cartridge style filter element.
In another aspect of the disclosure that may be combined with any of these aspects, the filter element comprises a pleated filter having a filter rating of 5 to 50 microns.
In another aspect of the disclosure that may be combined with any of these aspects, an ozone assembly may be provided that includes an ozone inlet in fluid communication with the bath, an ozone outlet in fluid communication with the bath, ozone piping extending from the ozone inlet to the ozone outlet, an ozone generator, and an ozone injector operably coupled between the ozone generator and the ozone piping.
In another aspect of the disclosure that may be combined with any of these aspects, an ozone monitor operably coupled to the bath.
In another aspect of the disclosure that may be combined with any of these aspects, a skimmer assembly may be provided having a skimmer inlet in fluid communication with the bath, wherein the separator fluidly communicates with the skimmer assembly.
In another aspect of the disclosure that may be combined with any of these aspects, the separator includes a separator tube having an inlet branch in fluid communication with the bath, an outlet branch, and a bypass branch extending between the inlet branch and the outlet branch, wherein lower ends of the inlet branch and outlet branch fluidly communicate with the tank interior chamber.
In another aspect of the disclosure that may be combined with any of these aspects, a bleed hole is formed in the inlet branch of the separator tube and a bleed tube disposed within the inlet branch and fluidly communicating with the bleed hole.
In another aspect of the disclosure that may be combined with any of these aspects, a filter assembly may include a filter housing defining a filter inlet in fluid communication with the separator outlet, and a filter outlet fluidly communicating with the pump inlet, and a filter element is disposed in the filter housing.
In another aspect of the disclosure that may be combined with any of these aspects, a vacuum pressure sensor is disposed upstream of the pump and configured to generate a signal when a pressure level reaches a predetermined pressure limit, and an operator alert is operatively coupled to the vacuum pressure sensor and configured to illuminate in response to the signal.
In another aspect of the disclosure that may be combined with any of these aspects, a separator assembly is provided for use in apparatus for separating and debris from an aqueous fluid disposed in a bath, the separator apparatus including a tank having a bottom wall and a sidewall extending upwardly from the bottom wall and defining a tank upper end, the tank defining an interior chamber, a lid sealingly coupled to the tank upper end, and a tank inlet tube in fluid communication with the bath. A separator tube is disposed in the tank interior chamber and includes an inlet branch in fluid communication with the tank inlet tube, an outlet branch, and a bypass branch extending between the inlet branch and the outlet branch, wherein lower ends of the inlet branch and outlet branch are disposed near a bottom end of the tank. A tank outlet tube fluid communicates with the separator tube outlet branch, and a weir is disposed in a bottom of the tank interior chamber to define a weir chamber located in a bottom of the tank, wherein the lower end of the separator tube outlet branch is disposed in the weir chamber.
In another aspect of the disclosure that may be combined with any of these aspects, the weir is attached to and extends upwardly from the tank bottom wall.
In another aspect of the disclosure that may be combined with any of these aspects, the weir is attached to the separator tube outlet branch.
In another aspect of the disclosure that may be combined with any of these aspects, both the tank inlet tube and the tank outlet tube extend through the tank side wall.
In another aspect of the disclosure that may be combined with any of these aspects, both the tank inlet tube and the tank outlet tube extend through the lid.
In another aspect of the disclosure that may be combined with any of these aspects, the separator tube is spaced from a centerline of the tank.
In another aspect of the disclosure that may be combined with any of these aspects, the separator tube inlet branch extends along an inlet branch centerline, the tank inlet tube includes a discharge opening disposed around an inlet tube centerline, and the inlet tube centerline is offset from the inlet branch centerline.
In another aspect of the disclosure that may be combined with any of these aspects, an air permeable foam breaker disposed in each of the inlet and outlet branches.
In another aspect of the disclosure that may be combined with any of these aspects, a tether is coupled to the air permeable foam breakers.
In another aspect of the disclosure that may be combined with any of these aspects, a skimmer assembly is provided for use in apparatus for separating and debris from an aqueous fluid disposed in a bath, the skimmer assembly including a suction hose defining an intake end, a float sleeve disposed around at least a portion of the suction hose, a skimmer body coupled to the suction hose intake end, the skimmer body defining a skimmer inlet opening, and a single float coupled to the skimmer body.
In another aspect of the disclosure that may be combined with any of these aspects, the skimmer body defines a body bottom wall having two opposing longitudinal edges and two opposing lateral edge, a body end wall extending upwardly from one of the longitudinal edges of the body bottom wall, two body side walls extending upwardly from respective lateral edges of the body bottom wall, and an inlet wall extending upwardly from a remaining one of the longitudinal edges of the body bottom wall, wherein the inlet wall extends partially toward a top edge of the body side walls so that the skimmer inlet opening is defined by the body inlet wall and an open top of the body.
In another aspect of the disclosure that may be combined with any of these aspects, the body inlet wall includes a central portion defining a linear central edge disposed at a first height above the body bottom wall, and two lateral portions defining linear lateral edges that extend from the central edge at the first height to terminal edges disposed at a second height above the body bottom wall, wherein the second height is greater than the first height.
While the present disclosure is susceptible to various modifications and alternative constructions, certain illustrative embodiments thereof have been shown in the drawings and will be described below in detail. It should be understood, however, that there is no intention to be limited to the specific forms disclosed, but on the contrary, the intention is to cover all modifications, alternative constructions, and equivalents falling within the spirit and scope of the present disclosure.
Exemplary embodiments of separating apparatus are disclosed herein for efficiently separating oil, floating solids, and suspended solids from an aqueous, or water-based, fluid. The aqueous fluid may be a solvent-type fluid such as a machining coolant, which may be synthetic, semi-synthetic, or soluble oil. The aqueous fluid is held in a bath. As used herein, the term “bath” is used to indicate the structure in which the aqueous fluid is collected during operation of the on-site equipment that uses the fluid, and may also be identified in the industry as a tank, a reservoir, a sump, a tub, or other equivalent term. The separating apparatus draws the fluid from the bath, separates oil, debris, and other contaminants from the aqueous fluid in stages, and returns the fluid to the bath. Various features discussed in greater detail below reduce the space requirements required for the apparatus, improve separation efficiency, and generally improve performance of the apparatus as compared to the previously known conventional designs.
An exemplary embodiment of a separating apparatus 10 is shown in
The skimmer assembly 12 is shown in greater detail in
The skimmer body 30 and inlet opening 32 may be configured to minimize clogging from debris. As best shown in
The separator assembly 14 is best shown in
A bleed hole 91 may extend through the inlet branch 86 to permit air from the tank interior chamber 82 to flow into the separator tube 84, as best shown in
A weir 98 may extend upwardly from a bottom wall 100 of the tank 80 to define a weir chamber 102 located in a bottom of the tank (
The inlet and outlet tubes 92, 94 may extend through a side wall 96 of the tank 80 as shown, or may be configured in a manner that does not require modification of the tank side wall 94. For example, in the alternative embodiment illustrated in
In operation, aqueous fluid from the suction hose 22 is discharged into the inlet branch 86 of the separator tube 84. The fluid and contaminants will then travel down the inlet branch 86 to collect in the interior chamber 82 of the tank 80. As the fluid collects inside the tank 80, it will separate into layers based on the density of the constituent fluid components. More specifically, the fluid will separate inside the tank 80 into an air layer 110 at the top, an oil layer 112 below the air layer 110, an oil emulsion layer 114 below the oil layer 112, an aqueous fluid layer 116 below the emulsion layer 114, and a solids layer 118 below the aqueous fluid layer 116. Solids collecting in the solids layer 118 are generally prevented by the weir 98 from entering the weir chamber 102. Additionally, the lower end 104 of the separator tube outlet branch 88 is positioned so that it is located within the aqueous fluid layer 116, so that fluid traveling up the outlet branch 88 is relatively free of debris and oil.
To further assist with the separation between the oil and oil emulsion layers 112, 114 on the one hand and the aqueous fluid layer 116 on the other hand, an optional oleophilic packing material 117 may be provided inside the tank 80. In the exemplary embodiment illustrated in
Air permeable foam breakers 120 may be inserted into the separator tube 84 to reduce the amount of foam exiting the tank 80. The foam breakers 120 may be formed of stainless steel wool or other suitable material that retains or minimizes foam while permitting air or other fluid to pass. The foam breakers 120 may be attached to a tether 121 to permit removal for cleaning the separator tube 84. A discharge valve 122 may extend through the tank side wall 94 at a height commensurate with the oil layer 112 and may be manually operable to drain a portion of the separated oil from the tank 80. In the embodiment illustrated in
Air that may be been pulled through the suction hose 22 may pass through the bypass branch 90 directly to the outlet branch 88. The inlet tube 92 may be configured to promote a spiral flow as the fluid enters the inlet branch 86, thereby reducing foam and promoting separation of air from the aqueous fluid. As best shown in
The filter assembly 16 is configured to receive aqueous fluid from the separator assembly 14 and remove suspended solids from the fluid. As best shown in
A pump 150 is provided for circulating the aqueous fluid through the separating apparatus 10. The pump 150 includes a pump inlet 152 in fluid communication with the filter outlet 136 and a pump outlet 154 that fluidly communicates with the bath 20 through a return hose 156. The pump 150 is located outside of the bath 20 and may be a rotary positive displacement pump, such as a rotary vane pump, a rotary gear pump, or a rotary hose/peristaltic pump. The pump 150 may have vanes and stators made of carbon or other material having advantageous heat-resistant characteristics. Additionally or alternatively, the vanes and stators of the pump may be coated with or formed of PEEK. In certain embodiments, the pump has a magnetic induction drive to further reduce contact between moving parts and improve pump life. Accordingly, a pump that is particularly suited for use in a separating assembly may be a rotary vane style to provide positive displacement of both liquid and air, has moving parts formed of relatively soft materials to reduce friction, and has vanes and stators formed of a material having high heat tolerance such as carbon. Still further, in applications where the fluid is a coolant, the coolant itself will further help reduce friction and heat generation, thereby further improving pump performance.
A vacuum pressure monitor may be provided to inform the use of a possible need to replace the filter element 138 or of a possible clog in the system. In an exemplary embodiment, the vacuum pressure monitor may include a vacuum switch 157 disposed in the system piping, such as downstream of the filter assembly 16 (
A vacuum relief valve 160 may be provided to prevent damage to the pump 150 or tank 80. In the illustrated embodiment, the vacuum relief valve 160 is formed in the filter base 132. The vacuum relief valve 160 may be located on the outlet side of the filter assembly 16 to protect all of the components of the separating apparatus 10, or on the inlet side of the filter assembly 16 to allow a higher vacuum across the filter element 138 and to increase filter element life. The vacuum relief valve 160 may be adjustable to permit varying degrees of vacuum depending on the rating of the filter element 138 and/or pump 150. The vacuum relief valve 160 will automatically open in response to excessive vacuum due to clogging of the filter element 138, skimmer body inlet opening 32, suction hose 22, or other component in the system. The vacuum relief valve 160 is a mechanical relief valve that may be provided as a substitute for, or in addition to, the vacuum pressure monitor noted above.
An optional ozone assembly 170 may be provided for treating the aqueous fluid to prevent bacteria or other biological growth. As best shown in
By providing multiple ozone generators 180 with multiple ozone injectors 182, the ozone assembly 170 permits adjustable ozone production and more reliable operation. The operator may choose how many generators 180 to run at a given time, thereby permitting adjustment of the amount of ozone generated. While two generators 180 are shown in the illustrated embodiment, more than two generators 180 are also contemplated. Additionally, with multiple generators 180, ozone is more reliably generated in the event a generator is disabled, as the other generator(s) will continue to operate. The use of multiple injectors 182 allows smaller ozone bubbles to be injected into the fluid stream that dissolve more quickly and increase the ozone content in the fluid. Also, the system will continue to operate even when an injector 182 is clogged.
The ozone monitor may detect a level of dissolved ozone or millivolts of oxidation reduction potential (ORP) in the aqueous fluid held in the bath 20. The ozone assembly 170 may be controlled to prevent diffusion of excessive ozone into the bath 20, which would waste energy and potentially damage the components of the separating apparatus 10. The ozone monitor may measure ozone levels (by measuring millivolts ORP, quantity of dissolved ozone, or other method) at an outlet stream once the ozone level has stabilized, which indicates the ozone level above which the ozone is excessive. The ozone monitor can then provide an ozone reading that indicates whether the contents of the bath 20 have been adequately sanitized.
To facilitate access to the interior enclosure space, at least some of the walls of the enclosure 250 may be hinged. For example, a hinge 284 may be provided in side wall 260 so that a top panel 286 may be rotated away from the interior enclosure space and toward a bottom panel 288. Similarly, a hinge 290 is provided in side wall 262 to permit a top panel 292 to rotate toward a bottom panel 294. Still further, a hinge 296 may be provided in front wall 252 that permits a top panel 298 to rotate toward a bottom panel 300. Then the top panels 286, 292, 298 are rotated outwardly, the interior enclosure space is more easily accessible.
The inlet hose 22, return hose 156, tank 80, and other components may be made of a material that is compatible not only with the aqueous fluid but also the oil and other contaminants, and may also be abrasion resistant to handle the passing of solids entrained in the fluid. The selected material may also be compatible with anti-bacterial, anti-fungal, or anti-microbial elements such as chlorine or ozone. The separator tube 84 may be formed of a material that resists rust, chemical reaction with the aqueous fluids and contaminants, and can withstand the vacuum pressure. Suitable material includes stainless steel (such as stainless steel 304 or other grades), mild steel, and plastic.
While only certain embodiments have been set forth, alternatives and modifications will be apparent from the above description to those skilled in the art.
These and other alternatives are considered equivalents and within the spirit and scope of this disclosure.