MXPA00012123A - Flat screen panel for crowned deck vibrating shaker - Google Patents

Abstract

A screen assembly for a vibrating shaker (10) having a crowned deck for receiving at least one screen assembly (12, 34) thereon and a plurality of attachment members. The screen assembly (12, 34) includes a rigid frame (36) having a pair of parallel, opposed sides (38, 40) and a pair of parallel, opposed ends (42, 44). An underside (54) of the frame (36) is radiused to match the crowned deck of the shaker (10). A top planar side (56) of the rigid frame (36) is opposed to the underside of the frame (54). At least one screen cloth layer (70, 72, 74) is fixed to the planar top side (56) of the frame (36) for separating solid materials from liquids and fine solid particles.

Description

FLAT SIZE PANEL FOR CONVEXA PLATFORM VIBRATORY AGITATOR DESCRIPTION OF THE INVENTION The present invention relates to a replaceable screen assembly for a vibratory agitator having a convex platform. In particular, the present invention is directed to a screen assembly having a rigid structure and an upper planar screen surface for use with a convex platform vibratory stirrer. Various types of designs and configurations of vibrating screen machines have been used in the past. These vibratory agitators are used as screening and separation devices in various industries, such as the drilling and mining industries to recycle drilling mud. A drilling fluid or slurry is circulated from the surface down through a drill string and down to an auger. After use in the drilling, the drilling mud, together with the waste and shavings of the drilling, is taken to the surface where it is sieved to remove solids of a certain size. A screen or sieve assembly is detachably secured to the vibrating agitator machine. With the sieve assembly or multiple sieve assemblies secured in place, a tray is formed with the opposite parallel side walls of the agitator. The drilling mud, together with the drilling chips and debris are deposited on the top of the screen assembly on one side. The screen assembly is vibrated at a high frequency or oscillation by a motor or motors for the purpose of sifting or separating the materials placed in the screen and feeding them thereto. The liquid and fine particles will pass through the screen assembly by gravity and will be recovered below it. Solid particles of a certain size migrate and vibrate through the sieve or sieves where they were removed. It is known how to obtain the proper vibration of the sieve assembly, of the looseness in the sieve wire that must be dissuaded. Any looseness in the wire mesh of the screen provides an undesirable shaking action of the screen which decreases adequate vibration and also results in increased wear of the wire mesh of the screen. Consequently, it is known that the screen assembly must be held securely and hermetically to the vibrating machinery. At the same time, the screen assemblies are subjected to stresses from the vibrating machinery and wear out over time and require periodic replacement. One type of linking mechanism includes hooks on each longitudinal end of the screen assembly for connection to the vibrating agitator machine. The agitator will have a traction bar in the form of a channel on each side which engages with a corresponding hook on the screen assembly. The drawbars are held in place by bolts or other fasteners. These are connected detachably so that the screens can be replaced from time to time. The vibratory agitator may include a bed or platform composed of a plurality of cushioned rails on which the screen assembly or assemblies rest. Instead of having the bed or platform for the flat or horizontal screen assembly, the bed can be modified to be arched, warped or curved upward so that the wire screen or screen assembly extends hermetically over the arched surface or curved. The height of the curvature of the platform can vary from 1.27 to 2.54 cm (1/2"to 1") from the center to the sides. A first example of a convex bed agitator is shown in Flint 1932 US Patent No. 1,886,173. With a convex bed, the screen wire or screen assembly must be flexible enough to fit the arch on the platform. Additional features to maintain tension include spring-loaded tension bolts to prevent loosening as the screens or screen assemblies extend and settle on the platform. The convex platform and the accompanying convex screen assembly can cause non-uniform fluid coverage. Due to the convex platform, the fluids and solids deposited in the sieve assembly to be separated will meet first on the sides. Depending on the fluid level, the arched center of the screen assembly may be exposed. The drilling mud to be sieved extends further along the sides of the screen platform than in the center where it is presented at the maximum height of the platform. This will reduce the effective sieve area of the vibrating agitator and reduce efficiency. This condition can also lead to mud losses in the discharge and contribute to unacceptable moisture cuts if the drilling fluid passes through the surface of the screen assembly without being sieved. Several measures have been used to respond to this. Manufacturers have modified the vibratory agitator to vary and alter the separation of the platform itself so that the drilling fluid moves upward from its entrance to the discharge. For example, the bed or platform can be set at an angle of inclination of 1 ° to 4 °. In other words, the fluid moves through the screen assembly and moves upward at the same time. However, the higher the angle of the platform, the shorter the sieve's useful life since the solids will move more slowly through the sieve, wearing it off as they move through it. The convex platform will result in the fluid being sieved forming a U towards the discharge end of the agitator. An alternative measure employed is to corrugate the screen assembly to provide flanges for contacting the fluid and assist in channeling thereof. Accordingly, it is known that flat panel screens can operate at a lower platform angle than arched platforms although it does not have the advantages of the curved or arched platform when promoting the tensioning of the screen assembly. Therefore, it is a primary object and purpose of the present invention to provide a screening assembly having a flat top surface for screening fluids and solids that couple with a convex platform vibratory stirrer. It is a further object and purpose of the present invention to provide a process for converting a convex platform vibratory agitator into a flat panel vibratory agitator.

It is a further object and purpose of the present invention to provide a flat panel screen for a convex vibratory agitator which will increase the production of fluid and, therefore, the efficiency of the vibratory agitator. It is a further object and purpose of the present invention to provide a process for converting a hook sieve vibrating stirrer into a hookless vibrating screen stirrer. The present invention provides a screen assembly for a vibratory agitator having a convex platform. The screen assembly includes a rigid structure that may be comprised of one piece, integral member or may be composed of discrete members configured together. The rigid structure includes a pair of parallel opposed sides and a pair of parallel opposed ends. A plurality of transverse supports extend between the ends and are parallel to each of the sides. The rigid structure includes a lower side that is radiated or arched to couple the radius of the convex platform. The lower side of the rigid structure is supported by and rests on a series of shock-absorbing rails. The rails, taken together, form an arch and form a radius that couples with the underside of the structure. The rigid structure also includes an upper planar side that is opposite the underside of the structure. A plurality of struts extend between the transverse supports and between the opposite sides. A clamping mechanism is provided to securely hold the screen assembly to the vibratory agitator. Each end of the structure contains a plurality of grooves for attaching the screen assembly to the vibratory agitator. Each slot is slightly larger than the head of a T-head bolt extending from a sidewall of the agitator. The T-headed bolts will pass through the slots at the end of the structure. The head of each bolt will pass through the slot in one orientation although the slot will not be allowed to pass in alternating orientations. Each bolt is locked in place by a threaded nut that is secured to the threaded head of the bolt and can have a rubber separator or o-ring to help seal against fluid spillage. Each end of the screen assembly is bevelled on the underside to accommodate the T-headed bolt before insertion into the slot. Each bevelled end may also include a gasket to help seal the screen assembly with the sidewall of the vibrating agitator.

Each end may also include a recess or indentation adjacent to each slot so that the T-headed pins will tend to be oriented in the locked position. A wire screen or a plurality of wire screens are attached to the upper planar side of the structure and can be tensioned therein. In an alternate embodiment, a perforated metal plate is secured to the upper planar side of the structure with the metal screen cloths attached thereto. BRIEF DESCRIPTION OF THE DRAWINGS Figures 1 and 2 illustrate prior art screen assembly designs for vibratory agitators; Figure 3 is a perspective view of a rigid structure for a screen assembly constructed in accordance with the present invention apart from the wire screen fabrics; Figure 4 is a top view of the stiff structure shown in Figure 3; Figure 5 is a sectional view taken along section line 5-5 of Figure 4; Figure 6 is a bottom view of the rigid structure shown in Figures 3, 4 and 5; Figure 7 is an end view of the rigid structure shown in Figures 3, 4, 5 and 6; Figure 8 is an enlarged view of the clamping mechanism for attaching the screen assembly to the vibratory agitator; Figure 9 is a sectional view of the screen assembly constructed in accordance with the present invention attached to a vibratory agitator; Figures 10 and 11 illustrate a perspective view of the screen assembly of the present invention apart from the vibratory agitator; Figure 12 is a perspective view of an alternative embodiment of the screen assembly of the present invention; and Figures 13 and 14 illustrate an alternative embodiment of the present invention. Referring to the drawings in detail, the Figures 1 and 2 illustrate an example of existing screen assembly designs of the prior art. Figure 1 illustrates a top view of a portion of a vibratory agitator 10 having a convex platform on which a hook screen assembly 12 is mounted. The screen assembly 12 is mounted between a pair of side walls 14 and 16, one of which is seen in partial section of Figure 2. A pair of traction bars in the shape of channel 18, one of which is seen in section in Figure 2, hold and retain opposing hooks 20, one of which is seen in Figure 2, which form the ends of the screen assembly 12. The channel-shaped traction rods 18 are put in place by a plurality of T-headed bolts 22 passing through openings in the openings. pull rods 18 and openings in the side wall 14. Threaded nuts 24 or other fasteners retain the T-headed bolts in place. An O-ring rubber gasket 26 can be juxtaposed between the side wall 14 and the nut. In order to replace the screen assembly 12, the nuts 24 are loosened from the T-headed bolts 22 so that the draw bars 18 become loose. The hooks 20 are uncoupled after the draw bars so that the screen assembly 12 or the screens can be removed. The replacement screen assembly can then be inserted and adjusted. The arcuate position of the screen assembly 12 can best be seen in Figure 2. A series of parallel cushion rails 30 retain and support the screen assembly. The fluid to be separated will be placed on top of the screen assembly. The platform can not only be arched but can be moved to positions with different inclination. The fluid cover in the screen assembly illustrates three different inclinations, as indicated by the shaded areas 31, 32 and 33. The shaded area 31 shows the platform at a 1 ° inclination. The shaded area 32 shows the platform at an inclination of 2 ° while the shaded area 33 shows the platform at a 3 ° inclination. The present invention provides a screen assembly 34 for a convex platform vibratory stirrer that will replace the prior art screen configuration shown in Figures 1 and 2. Figure 3 is a perspective view of a rigid structure 36 that is a part of the screen assembly 34 of the present invention. Figures 4 to 7 illustrate different views of the rigid structure 36 apart from the rest of the screen assembly. The rigid structure may be comprised of a single integral member of a piece or may be composed of several members configured together. The rigid structure can be manufactured from steel, aluminum, plastic, rubber or fiberglass and can be manufactured through various processes, such as injection molding, compression molding or stretch extrusion. The stiff structure 36 includes a pair of parallel opposed sides 38 and 40 and a pair of parallel opposed ends 42 and 44. The sides in the present embodiment are larger than the ends to form an elongated rectangle although it will be understood that other configurations, such as as a square, they are possible and are within the scope of the invention. A plurality of transverse supports 46, 48, 50 and 52 extend between the ends 42 and 44 and are parallel to the sides 38 and 40. The number of transverse supports will vary depending on the size of the design and the invention is not limited to a number particular of transverse supports. As best seen in Figures 3 and 5, the rigid structure 36 includes a lower side 54 that is radiated or arched to engage the radius of the convex platform. Additionally, each of the transverse supports has a lower side that is arched or radiated to engage the convex platform. The rigid structure 36 also includes an upper planar side 56 which is opposite the lower side 54 of the structure. A plurality of braces 60, 62 and 64 extend between the transverse supports and between the transverse supports and the opposite sides. The straps in the present embodiment are perpendicular to the sides and in the transverse supports although they can move diagonally. The straps in the present modality are not level with the upper part although they could be. A clamping mechanism is provided to securely hold the screen assembly to the vibratory agitator. Each end of the structure 42, 44 contains a plurality of slots 66 for joining the screen assembly. Each slot is slightly larger than the head of the T-head bolt 22. Alternatively, the slot 66 may have the notch shape (not shown) at the ends. With specific reference to Figure 6, the lower side 54 of the stiff structure 36 may be covered with an elastic material 68. Figures 8 and 9 illustrate a preferred form of removable attachment of the screen assembly 34 to the vibratory agitator. Figure 8 shows the screen assembly 34 attached to the vibratory agitator 10 between the side walls 14 and 16. The underside 54 of the structure 36 is supported by and rests on a series of cushion rails 30. The rails, considered together , they form an arc and a radius that engages with the underside 54 of the structure. The arc in the present embodiment moves from end to end although other orientations are possible within the scope of the invention. A T-headed bolt 22 is illustrated in enlarged form in Figure 8. The T-headed bolt passes through the slot 66 at the end 42 of the structure 36. The T-head of the bolt will pass through the bolt. slot 66 in a rotational orientation although it will not be allowed to return out of the slot in an alternate rotational orientation as shown in Figures 7 and 8. For example, the bolt 22 may pass through the slot 66 in an orientation but will be it prevents returning if it rotates 90 °. The bolt 22 also passes through an opening in the side wall 14 of the vibrating agitator. It is held in place by a threaded nut 24 which is secured to the threaded end of the bolt 22 and can have a spacer 26 and an O-ring 28. Each end 42 and 44 of the screen assembly 34 is bevelled on the underside to accommodate the T-headed bolts 22 before insertion into and through the slot 66. In other words, the bolt heads will reside in the bevelled space while the screen assembly is lowered onto the platform. Each bevelled end includes a gasket 68 in order to seal the screen assembly 34 with the side wall 14 of the vibrating agitator. In order to install the screen assembly 34 on a convex platform vibratory agitator, the pair of drawbars 18 described in connection with the prior art are removed by unscrewing and loosening the T-headed bolts from the nuts 24. Subsequently , the screen assembly 34 is lowered onto the arcuate platform of the agitator so that the lower side 54 bears against the rails 30. Each head of the fixing bolts 22 is then inserted through a slot opening in the end. Each bolt with a T-head is rotated approximately 90 °. The end 42 may also include a recess or indentation 70 adjacent each slot 66 so that the T-head bolt will tend to be oriented in the locked position. The threaded nut 24 is then secured on the bolt 22. The pull rods, which will trap debris and mud, are no longer required with the present invention. The elimination of the drawbars results in a quicker and easier replacement of the screen assembly. Alternatively, the screen assembly 34 can be removably attached to the vibratory agitator by wedge blocks (not shown) as will be described in a further embodiment below. Figures 10 and 11 illustrate one embodiment of the screen assembly 34 in a plurality of wire screen fabrics 72, 74 and 76 are attached to the upper plane side of the structure and tensioned thereon. Figure 10 shows the screen metal screens partially cut for clarity. A thick reinforcing layer 72 will engage the structure, a thin intermediate layer 74 will be placed on it, and a thin top layer 76 will go on top. The wire screens are extended and tensioned to the structure and then fixed with epoxy or another adhesive. It will be appreciated that a greater or lesser number of metal screens can be used.

Figure 12 illustrates an alternative embodiment 78 of the present invention wherein a perforated plate 80 is secured to the upper planar side of the structure with the metal screen fabrics attached thereto. A perforated plate 80 is mounted on and secured to the upper plane side of the rigid structure. A wire mesh screen or multiple screen wire cloths 82, 84 and 86 are secured on top of the perforated plate. Figure 13 illustrates an alternative embodiment 90 of the present invention. A rigid structure 92 is constructed in a manner similar to the modalities previously described. Once the drawbars have been removed and the structure 92 is installed on the rails 30, a flat platform is created. In this embodiment, no cloth or screen wire is attached to the upper plane side of the structure 92. Instead, a separate disposable screen 94 is attached to the formed structure 90. The disposable screen 94 includes a tubular support structure 96 that rests on the upper plane side. A sieve wire or multiple sieve screen 98 are secured to the tubular support structure 96. Other types of planar sieves or screen assemblies may also be used.

The screen 94 is held in place by a pair of wedge blocks 100 that are wedged or forced between the top of the screen and the angle iron 102 extending from the sidewall of the agitator. Alternatively, the screen 94 can be secured to the rigid structure 92 by fasteners (not shown) the present invention in any of its modes eliminates the need for a convex platform and allows a lower platform inclination angle. The non-uniform U-shaped fluid coverage is eliminated, resulting in increased production. This allows the use of finer sieves, if desired, while maintaining fluid capacity requirements. Considering that the present invention has been described in connection with the drawings appended hereto, it should be understood that other modifications, other than those shown or suggested herein may be made within the spirit and scope of the invention.

Claims (25)

1. CLAIMS 1. A screen assembly for a vibratory agitator having a convex platform for receiving at least one screen assembly therein and having a plurality of clamping members, which screen assembly is characterized in that it comprises: a structure that it has a pair of parallel opposite sides and a pair of parallel opposite ends; a lower side of the radiated structure for coupling the convex platform; an upper plane side of the structure opposite the lower side; and at least one layer of screen wire attached to the upper plane side of the structure to separate solid materials from liquids and fine solid particles.
2. 2. The screen assembly for a vibratory agitator according to claim 1, characterized in that the opposite sides have lower sides that are radiated to couple the convex platform.
3. The screen assembly for a vibratory agitator according to claim 2, characterized in that it includes a plurality of transverse supports extending between the ends parallel to the sides, each transverse support having lower sides which are radiated to couple the platform convex .
4. The screen assembly for a vibratory agitator according to claim 3, characterized in that it includes a plurality of struts extending between the transverse supports.
5. The screen assembly for a vibratory agitator according to claim 3, characterized in that the structure of the transverse members are rigid and are manufactured as a single integral member.
6. 6. The screen assembly for a vibratory agitator according to claim 1, characterized in that at least one screen layer is tensioned to the flat upper side of the structure.
7. The screen assembly for a vibratory agitator according to claim 6, characterized in that it includes a plurality of struts extending between the transverse supports.
8. The screen assembly for a vibratory agitator according to claim 1, characterized in that it includes three of the wire mesh screen layers attached to the flat upper side of the structure.
9. The screen assembly for a vibratory agitator according to claim 1, characterized in that it includes a perforated plate secured to the flat upper side of the structure wherein at least one screen layer is fixed to the perforated plate.
10. The screen assembly for a vibratory agitator according to claim 9, characterized in that it includes three layers of metal screen cloth attached to the perforated plate.
11. A screen assembly for a vibratory agitator according to claim 1, characterized in that the vibrating agitator includes a pair of side walls, wherein the agitator fastening members are T-headed bolts that are retained by the side walls. , and wherein the screen assembly includes a plurality of openings through the opposite ends of the structure in order to receive the bolts therethrough.
12. 12. The screen assembly for a vibratory agitator according to claim 11, characterized in that it includes a recess adjacent to each opening at each end to act as a guide for coupling the T-head bolts.
13. 13. The screen assembly for a vibratory agitator according to claim 1, characterized in that the end opening is a groove.
14. The screen assembly for a vibratory agitator according to claim 1, characterized in that each end of the opposite structure is bevelled from the upper plane side to the lower side.
15. 15. The screen assembly for a vibratory agitator according to claim 14, characterized in that each bevelled end includes a seal for sealing with a side wall of the vibrating agitator.
16. 16. The screen assembly according to claim 1, characterized in that the opposite sides are joined to the opposite ends and where each side extends beyond the ends.
17. 17. The screen assembly according to claim 1, characterized in that the lower side of the structure includes a joint for coupling with the convex platform.
18. 18. A method for converting a convex platform vibratory agitator having a radiated platform to a flat screen vibratory agitator, which method is characterized in that it comprises: coupling a rigid structure having a radiated lower side and an upper flat side towards the platform convex stirrer; inserting a plurality of fixing bolts extending from the agitator through the openings in the structure ends; attach the clamping bolts that extend from the agitator to the structure ends; and clamping the holding bolts to hold the screen assembly towards the agitator.
19. The method for converting a convex platform vibratory agitator according to claim 18, characterized in that it includes the additional initial step of removing a pair of traction bars in the form of a channel from the agitator.
20. The method for converting a convex platform vibratory agitator according to claim 18, characterized in that it includes the additional initial step of forming the rigid structure as a single integral member.
21. 21. The method for converting a convex platform vibratory agitator in accordance with the claim 18, characterized in that it includes the additional initial step of molding the rigid structure as a single integral member.
22. 22. A method for converting a hook-type vibrating stirrer having a pair of sidewalls, a pair of drawbars and a plurality of fastening members, into a vibrating screen agitator without hooks, the method is characterized in that it comprises : remove the pair of drawbars from the vibrating agitator; inserting the clamping members through the openings at opposite ends of a screen assembly; coupling the clamping members with the screen assembly; and clamping the clamping members to retain the screen assembly.
23. The method for converting a hook-type vibrating stirrer according to claim 20, characterized in that it includes the step of providing recesses at each adjacent end opposite the opening as a guide for coupling the clamping members with the screen assembly. .
24. 24. A screen assembly for a vibratory agitator having a convex platform for receiving at least one screen assembly therein, which screen assembly is characterized in that it comprises: a structure having a pair of parallel opposed sides and a pair of opposite parallel ends; a lower side of the radiated structure for coupling the convex platform; an upper planar side of the structure opposite the lower side; a clamping mechanism to attach the structure to the agitator; and a replaceable screen secured detachably to the rigid structure.
25. 25. A screen assembly according to claim 24, characterized in that the clamping mechanism includes a pair of wedge blocks which are wedged between angled irons extending from the side walls from the agitator and the replaceable screen.