Patent Application
20190091706
The present application relates generally to, but is not limited to, the field of foundry sand reclamation. More specifically, the present application relates to a nozzle configured to induce cavitation in order to recover sand and clay that are bound together during the foundry process.
During the foundry process, parts are cast in molds formed from molding sand. The sand defines a female mold shape, which is filled with molten metal (e.g., iron). When the molten metal is introduced to the mold, heat is transferred from the molten metal to the sand, firing (e.g., chemically bonding) and baking at least a portion of sand, forming a coating on the sand, and thereby generating hardened spent sand. Furthermore, sand may be held together by clay from the foundry process. This spent sand and clay must then be mixed with new molding sand before being used in a mold. For example, in order to maintain a desired ratio of new sand to spent sand, a portion of the spent sand is discarded after each casting process and replaced with the new molding sand. The spent sand and clay is typically discarded in a landfill, having a negative environmental impact.
Alternatively, a process for reclaiming the spent sand and clay includes incinerating the spent sand and clay. During the incineration process, the spent sand and clay is heated to a very high temperature, until the bond is broken down and the sand grains separate from each other. This process requires large fuel inputs and is therefore both costly to operate in order to generate sufficient heat, as well as subject to regulatory restrictions.
One embodiment relates to a nozzle assembly for generating cavitation, comprising an inlet nozzle having a first end and an opposing second end. The inlet nozzle further includes an inlet bore extending from the first end to the second end, the inlet bore defining a first cross-sectional area at the first end and a second cross-sectional area at the second end. The second cross-sectional area is less than the first cross-sectional area, such that the inlet bore is configured to decrease pressure in a fluid from the first end to the second end, thereby forming vapor pockets in the fluid. The nozzle assembly further includes an outlet nozzle having a first end and an opposing second end. An outlet bore extends from the first end to the second end, the outlet bore configured to receive fluid from the inlet bore.
Another embodiment relates to a method of isolating spent sand and clay from a foundry process, comprising receiving a mixture of spent sand, clay and water in an inlet nozzle of a nozzle assembly, and generating cavitation bubbles in the water. The method further includes collapsing at least a portion of the cavitation bubbles around the spent sand and clay and outputting energy from collapsing cavitation bubbles. The method further includes breaking apart at least a portion of the spent sand and clay with the energy from the collapsing cavitation bubbles, forming a separated sand and clay, and outputting the separated sand and clay.
As is discussed below, various embodiments disclosed herein provide for advantages such as by providing a sand and clay reclamation process that does not require excessive heat and breaks apart spent sand and clay for reintroduction to the foundry process.
Referring to the figures generally, a nozzle assembly for generating cavitation is shown according to various embodiments. The nozzle assembly receives water carrying spent sand and clay therethrough and is configured to generate turbulent flow, lowering the pressure in water in order to four gas pockets. As pressure increases in the flow, the gas pockets collapse, causing cavitation in the water, breaking apart the spent sand and clay. The nozzle assembly will now be described in further detail.
Referring now to
An inlet pipe flange 30 is disposed on the first end 18 of the inlet nozzle 12 and defines an inlet collar 32 extending axially outward from the nozzle assembly 10, the inlet collar 32 configured to receive and fluidly couple to PVC or other piping therein. For example, the inlet collar 32 of the inlet pipe flange 30 may define an inner diameter configured to receive 3 inch PVC piping when the nozzle assembly 10 is installed in a reclamation system, as will be discussed in further detail below. The inlet collar 32 is fluidly coupled to the inlet bore 22 and is configured to receive fluid therethrough and output the fluid to the inlet bore 22. The inlet pipe flange 30 defines a plurality of bolt bores 34 formed annularly about the inlet pipe flange 30. A first gasket 36 (e.g., O-ring) is disposed between the inlet pipe flange 30 and the first end 18 of the inlet nozzle 12. For example, the first gasket 36 may be compressed between the inlet pipe flange 30 and the inlet nozzle 12, such that the inlet pipe flange 30 sealingly engages the inlet nozzle 12. The first gasket 36 defines a plurality of bolt bores 34 formed annularly about the first gasket 36 and corresponding to and axially aligned with the bolt bores 34 of the inlet pipe flange 30.
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Each of the first and second ends 50, 52 may further define a sealing groove 62 formed annularly about the orifice opening 54. Complementary sealing grooves 62 may also be defined in the second end 20 of the inlet nozzle 12, formed annularly about the inlet bore 22, and the first end 24 of the outlet nozzle 14, formed annularly about the outlet bore 28. As shown in
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The outlet nozzle 14 further includes a plurality of recesses 68 formed in the outlet bore 28. As shown in
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As the fluid carrying the spent sand and clay is passed through the outlet nozzle 14, the vapor pockets collapse in the outlet bore 28, generating cavitation. Furthermore, after the fluid is output from the nozzle assembly 10, remaining vapor pockets may collapse in the piping, generating cavitation outside of the nozzle assembly 10. As discussed above, when the vapor pockets collapse, energy is dispersed into the spent sand and clay. Small shockwaves cause the spent sand and clay to break apart into component parts of large and small grain sand particles, ceramic (e.g., originally lining the molding sand before introduction of molten metal to the mold), solidified metal material, and clay. These components may then be separated for reuse in the foundry process. It should be understood that cavitation may cause damage to the nozzle assembly 10. In order to improve the lifecycle of the nozzle assembly 10, at least portions of the nozzle assembly 10 may be formed from polyurethane or high-chromium alloys, configured to withstand cavitation.
Referring now to
The nozzle assembly 10 receives the water-sand mixture from the nozzle feed line 110 and as the water-sand mixture is passed through the nozzle assembly, the water in the mixture generates cavitation, breaking apart the sand in the mixture to isolate sand from ceramic, clay, and other sediments in the mixture. The cavitation may occur within the nozzle assembly 10 and/or downstream from the nozzle assembly 10 in a nozzle output line 112, configured to receive the fluid output from the nozzle assembly 10. The nozzle output line 112 passes over a plurality of sand settling tubes 114. The sand settling tubes 114 may include grates or other structures configured to allow water and isolated (e.g., separated) sand to pass through, while preventing larger sediments including ceramic and clay from passing therethrough. The water and isolated sand are supplied to a lower end 118 of an inclined dewatering screw 116 configured to separate sand from water and output isolated sand. The screw 116 is rotated, such that isolated sand is carried to an upper end 120 of the screw 116 and the water remains proximate the lower end 118. The isolated sand is then carried away from the screw 116 on a conveyer 122 (e.g., screw conveyer, belt conveyer, etc.) to a cooler 124 (e.g., Hartley cooler) for cooling the isolated sand. For example, the sand may be introduced to the reclamation system 100 at an elevated (e.g., above ambient) temperature due to heat transferred to the sand from the foundry process. Once the sand is isolated, it can be reused in the foundry process as new (e.g., reclaimed, fresh, isolated, separated) sand or may be exported from the reclamation system 100 for other purposes (e.g., sold). In some embodiments, if more water and isolated sand are fed from the sand settling tubes 114 to the dewatering screw 116 than the dewatering screw 116 has capacity to process, at least a portion of the water and isolated sand may overflow to the holding tank 106. Further, if additional water is needed at the dewatering screw 116, water may be supplied from the holding tank 106, from the water supply (i.e., first water supply) 108 or from a separate second water supply 126.
Remaining sand, water, and other sediments may pass over other collection tanks for removing ceramic, clay, or other sediments. These collection tanks may separate sediment in a substantially similar way to the sand settling tubes 114. Any sand, water, and clay in the nozzle output line 112 that is not separated is then returned to the holding tank 106 for reintroduction to the nozzle assembly 10 through the nozzle feed line 110. In this configuration, the water-sand mixture may recirculate through the reclamation system 100 until substantially all of the sand or other sediments are recovered. Accordingly, in the reclamation system 100 land fill waste can be substantially reduced or eliminated.
As utilized herein, the terms “approximately,” “about,” “substantially,” and similar terms are intended to have a broad meaning in harmony with the common and accepted usage by those of ordinary skill in the art to which the subject matter of this disclosure pertains. It should be understood by those of skill in the art who review this disclosure that these terms are intended to allow a description of certain features described and claimed without restricting the scope of these features to the precise numerical ranges provided. Accordingly, these terms should be interpreted as indicating that insubstantial or inconsequential modifications or alterations of the subject matter described and claimed are considered to be within the scope of this disclosure as recited in the appended claims.
It should be noted that the term “exemplary” as used herein to describe various embodiments is intended to indicate that such embodiments are possible examples, representations, and/or illustrations of possible embodiments (and such term is not intended to connote that such embodiments are necessarily extraordinary or superlative examples).
The terms “coupled,” “connected,” and the like as used herein mean the joining of two members directly or indirectly to one another. Such joining may be stationary (e.g., permanent) or moveable (e.g., removable or releasable). Such joining may be achieved with the two members or the two members and any additional intermediate members being integrally formed as a single unitary body with one another or with the two members or the two members and any additional intermediate members being attached to one another.
References herein to the position of elements (e.g., “top,” “bottom,” etc.) are merely used to describe the orientation of various elements in the FIGURES. It should be noted that the orientation of various elements may differ according to other exemplary embodiments, and that such variations are intended to be encompassed by the present disclosure.
It is to be understood that although the present invention has been described with regard to preferred embodiments thereof, various other embodiments and variants may occur to those skilled in the art, which are within the scope and spirit of the invention, and such other embodiments and variants are intended to be covered by corresponding claims. Those skilled in the art will readily appreciate that many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, mounting arrangements, use of materials, orientations, manufacturing processes, etc.) without materially departing from the novel teachings and advantages of the subject matter described herein. For example, the order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments. Other substitutions, modifications, changes and omissions may also be made in the design, operating conditions and arrangement of the various exemplary embodiments without departing from the scope of the present disclosure.
