Adjustable vacuum pan assemblies for belt filters

An adjustable vacuum pan assembly [190] for a belt filter [900] is disclosed. The adjustable vacuum pan assembly [190] comprises an arm [140] configured to be attached to a frame portion [930] of the filter [900], a vacuum pan [150] adjustably connected to the arm [140], and a cam [170] operatively coupled to the arm [140]. The cam [170] is rotatable with respect to the arm [140] and has a peripheral surface which contacts a portion [157] of the vacuum pan [150]. The assembly [190] further comprises a locking member [169] which serves to hold the cam [170] against rotation with respect to the arm [140]. Varying an angular rotational position of the cam [170] effectively varies a spacing between the vacuum pan [150] and the arm [140], thereby providing an amount of misalignment compensation therebetween. Retrofit kits for a preexisting conventional filter [900] and methods of providing increased adjustability to a filter [900] are also disclosed.

BACKGROUND OF THE INVENTION

This invention relates to filtration processes and equipment, and more particularly to horizontal belt filter apparatus, particularly for use in minerals processing.

FIGS. 1,2, and4show a horizontal belt filter900having a conventional vacuum pan assembly990. Horizontal belt filter900comprises a frame930, a plurality of return rollers920and a drainage belt910having a number of pores912provided therein which are configured to pass fluid and moisture from a slurry (not shown) to the conventional vacuum pan assembly990positioned below the belt910. Belt910supports filter media914such as a filter cloth. Conventional vacuum pan assembly990comprises a swing arm940which is pivotally attached to said frame930by way of a pivot bracket941having a first pivot member946, and a second pivot member936provided to the frame930. A vacuum pan950having an elongated inlet951and a channel952is mounted to the swing arm940via a number of fasteners953passing through at least one mount957on the pan150. A wear plate959having a number of apertures955may serve as a sacrificial interface between the pan150and the belt910. Apertures955in the wear plate959allow fluid and moisture from slurry passing through pores912to enter the conventional vacuum pan assembly990positioned below the belt910. A first securing portion944is provided to a distal end of the swing arm940, opposite the pivot bracket941and the first pivot member946. The first securing portion944is configured to mate with a complementary second securing portion (not shown) provided at a predetermined location on the frame930of the filter900. Engagement between the first securing portion944and the second securing portion (not shown) serves to keep vacuum pan950and wear plate959in close communication with belt910.

As best shown inFIGS. 2 and 3, at least one shim960is typically placed between the swing arm940and mount957to better align the inlet951of the pan950with the pores912in the belt910and sometimes to adjust the tilt of the pan950to match an inclination of the belt910. The exact number and/or configuration of shims960may vary between each swing arm940and mount957along the length of the filter900, and will frequently change as portions of wear plate959dimensionally change (e.g., in thickness) due to continued friction with the belt910.

A significant disadvantage of using shims960is that when used wear plates959are replaced with thicker new wear plates (or when any portion of the conventional vacuum pan assembly990such as the pan950itself needs to be removed for routine maintenance or cleaning), there is no simple way to restore the position of the pan950to a “factory default” alignment configuration with respect to the swing arm940. In other words, shims960necessary for use with thin worn wear plates959, which are removed from the assembly990to accommodate thick new wear plates959, will need to be replaced in a new configuration in a lesser number in order to bring the pan950into proper re-alignment with the belt910. Such re-configuring and adjustment steps require unnecessary downtime and labor.

To add to the abovementioned problem, shims are typically custom-fabricated at each shim location. Multiple shims of varying thickness are required at each shim point to achieve the desired elevation required for belt-to-pan alignment and proper vacuum seal between the belt910and vacuum pan assembly990. Shims960are frequently lost, mixed up or accidentally confused with other shims960, and additional shims960may need to be quickly fabricated and provided in the field in order to adjust the positioning of the vacuum pan950during routine maintenance.

Jack screws often “seize” in place after a short time in operation, thereby resulting in the inability to adjust the elevation or removal of vacuum pan950during routine maintenance. Neither shims960or jack screws (not shown) provide a quick and efficient way to re-establish “factory-set elevation points” for a vacuum pan950after maintenance adjustments are performed.

Conventionally, the horizontal adjustment of vacuum pans950typically involves welding an adjusting plate (not shown) to the swing arm in-situ during assembly. As a result of in-situ welding, additional cleaning of the weld area and protective repainting is required. These extra steps add to the total commissioning time and cost. Moreover, welding exposes expensive components (e.g., belt910) to potential damage.

OBJECTS OF THE INVENTION

It is, therefore, an object of the invention to provide a vacuum pan assembly which reduces down time for users during routine maintenance.

It is also an object of the invention to provide a vacuum pan assembly which requires less shop assembly time and does not require welding and subsequent protective painting.

It is also an object of the invention to provide a vacuum pan assembly adjustment mechanism which is easily adapted for and configured to be used with current filters using shims and jacks, thereby providing a valuable aftermarket conversion kit.

It is also an object of the invention to provide a device which enables a user of a filter to adjust a vacuum pan both vertically and horizontally using a single mechanism.

It is also an object of the invention to provide adjustment means to a vacuum pan which allows horizontal adjustment without the need for a providing a separately-welded adjusting plate, and welding in assembly.

These and many other objects of the invention will be apparent from the drawings and description herein. Although every object of the invention is believed to be attained by at least one embodiment of the invention, there is not necessarily any one embodiment of the invention that achieves all of the objects of the invention.

SUMMARY OF THE INVENTION

An adjustable vacuum pan assembly for a belt filter is disclosed. The adjustable vacuum pan assembly comprises an arm configured to be attached to a frame portion of the filter, a vacuum pan adjustably connected to the arm, and a cam operatively coupled to the arm. The arm may comprise a swing arm which is pivotally attached to said frame portion of the belt filter. The cam is rotatable with respect to the arm and has a peripheral surface which contacts a portion of the vacuum pan. The assembly further comprises a locking member which serves to hold the cam against rotation with respect to the arm. Varying an angular rotational position of the cam effectively varies a spacing between the vacuum pan and the arm, thereby providing an amount of misalignment compensation therebetween. In some embodiments, the cam is operatively coupled to the arm via a bracket which may be adjustably positionable with respect to the arm in at least one direction. In some embodiments, the locking member selectively engages one of a plurality of engagement surfaces on the cam to maintain a spacing between the vacuum pan and the arm. In some embodiments, means for applying a torque to the cam is provided. In some embodiments, the cam rotates about an axis defined by a pin, and the position of the cam along said axis may be adjusted and then limited or maintained by a stop one or more retainers.

A belt filter is also disclosed, wherein the belt filter comprises an adjustable vacuum pan assembly as described above.

A retrofit kit for a filter is also disclosed. The kit comprises a bracket configured to be mounted to an arm or other frame portion of a filter, a cam configured to be operatively coupled to said bracket, and a locking member configured to hold the cam against rotation with respect to the bracket. The arm may comprise a swing arm which is pivotally attached to said frame portion of the belt filter. The cam is rotatable with respect to the bracket and has a peripheral surface which is configured to contact a portion of a vacuum pan or other component. In use, varying an angular rotational position of the cam effectively varies a spacing between a vacuum pan and said bracket, thereby providing an amount of misalignment compensation therebetween.

Also disclosed is a method of providing increased adjustability to a conventional vacuum pan assembly in a filter. The method comprises the steps of providing a cam to an arm or frame portion of a filter, providing a locking member to hold the cam against rotation with respect to the arm or frame portion, varying an angular rotational position of the cam to effectively vary a spacing between a vacuum pan and the arm or frame portion, thereby providing an appropriate amount of misalignment compensation therebetween, locking the cam from rotation using the locking member, and maintaining an appropriate spacing between a vacuum pan and said arm or frame portion during operation of said filter.

DETAILED DESCRIPTION OF THE INVENTION

FIGS.3and5-8show an improved adjustable vacuum pan assembly190. The vacuum pan assembly190comprises a swing arm140which is pivotally attached to a frame portion of a filter900(e.g., a horizontal belt filter). Swing arm140comprises a pivot bracket141having a first pivot member146configured to communicate with a second pivot member936such as a pin, dowel, hinge, fulcrum, or other equivalent device provided to the frame930of the filter900. In the exemplary embodiment shown, first pivot member146is provided as an aperture suitable for receiving a pin or rod; however, the first pivot member146may equally be a portion of a hinge or other pivoting mechanism without limitation. A vacuum pan150having one or more effluent ports158, an elongated inlet151, and a channel152suitable for collecting, retaining, and delivering fluid and moisture is mounted to the swing arm140via at least one fastener153passing through at least one mount157on the pan150. One or more wear plates159having a number of apertures155may serve as a sacrificial interface between the pan150and a belt910. Apertures155in each wear plate159allow fluid and moisture passing through pores912of a belt910to enter the vacuum pan assembly190positioned below the belt910. While not shown, it is envisaged that each wear plate159may alternatively comprise two parallel wear plates having therebetween, a spacing which similarly allows fluid to pass. A first securing portion144is provided to a distal end of the swing arm140, opposite the pivot bracket141and first pivot member146. The first securing portion144is configured to mate with a complementary second securing portion (not shown) provided at a predetermined location on the frame930of a filter900. Engagement between the first securing portion144and the second securing portion (not shown) serves to keep vacuum pan150and wear plate159in close communication with belt910.

Fine adjustability of spacing between the pan150and the swing arm140is achieved through the use of at least one cam170which initially supports the mount157of the pan150in at least a Z-axis direction extending between an upper and lower portion of the filter900. Cam170is rotatable through a range of motion in at least one rotational degree of freedom. The at least one rotational degree of freedom is shown to be about an axis which is generally parallel with a long axis of the swing arm140extending between the pivot bracket141and first securing portion144. However, while not shown, said at least one rotational degree of freedom may alternatively be about an axis which is generally perpendicular with respect to a long axis of the swing arm140as will be described in more detail below. In some preferred embodiments, the cam170is round and allows independent vertical adjustment of the pan150in the Z-axis direction in 0.5-5 mm increments, and even more preferably between 1 mm and 3 mm increments—for example, 1.5 mm increments.

Swing arm140comprises a set of one or more oblong openings142which may extend longitudinally in an X-axis direction within an X-Z plane which is generally transverse to the filter900. One or more fasteners163extend through said oblong openings142and hold a bracket160to the swing arm140. The elongated nature of the oblong openings142allows bracket160to be mounted to the swing arm140with some amount of positional adjustability in at least said X-axis direction. In the embodiment shown, bracket160comprises a set of one or more openings161which are configured to receive the fasteners163. However, it is contemplated that while not shown, oblong openings142may instead be provided on the bracket160, and openings161may be provided to the swing arm140. Moreover, other means for X-axis positional adjustment may be provided, including, but not limited to: tracks, channels, sliding dovetail joints, linear bearings, or the like.

Swing arm140further comprises a set of one or more oblong openings143which may extend longitudinally in an X-axis direction within an X-Y plane which is generally parallel to belt910. One or more fasteners153extend through said oblong openings143and hold mount157to the swing arm140. The elongated nature of the oblong openings143allows pan150to be mounted to the swing arm140with some amount of positional adjustability in at least the X-axis direction. Similarly, one or more mounts157provided to the vacuum pan150may comprise a set of one or more oblong openings156which may extend longitudinally in a Y-axis direction within said X-Y plane. Fasteners153extend through said oblong openings143,156and secure the mount157(and therefore, pan150) to the swing arm140. The elongated nature of the oblong openings156allows pan150to be mounted to the swing arm140with some amount of positional adjustability in at least the Y-axis direction. While not shown, it is contemplated that oblong opening sets143and156may be interchanged without negatively affecting function. Moreover, oblong openings143,156may be collectively replaced with other means for X-Y planar positional adjustment including, but not limited to: perpendicular tracks, perpendicular channels, perpendicular sliding dovetail joints, planar bearings, etc. While specifically shown as nuts and bolts, it should be noted that fasteners153,163according to the invention may be of any suitable type including, but not limited to: headed rivets, clevis pins, weld studs, and the like.

Bracket160comprises a pin165which is configured to receive a cam170via an aperture177provided to said cam170which is offset of center (i.e., the cam170is eccentric). Pin165may be modular (e.g., provided as a bolt secured to the bracket160with a nut), or pin165may be permanently attached to the bracket (e.g., a weld stud).

A torque boss171may be provided to the cam170. In some embodiments, torque boss171is concentric or otherwise co-axial with said aperture177. Cam170further comprises a plurality of engagement surfaces178which are displaced various distances from said aperture177and are positioned at different locations relative to the aperture177. The engagement surfaces178are configured to accept a locking member169which is adapted to fix the cam170in place in at least 5 degrees of freedom with respect to the bracket160. In the very least, locking member169prevents a rotational movement of the cam170. In some embodiments, cam170may be permitted to move in a direction along the axis of pin165and aperture177(i.e., in an X-axis direction) and contact a stop154provided on the pan150or pan mount(s)157or other portion of the assembly190in order to limit lateral movement of the cam170. Smooth peripheral surfaces on the cam170enable some amount of horizontal displacement of the cam170in the X-axis direction or Y-axis direction, without affecting the vertical positioning of the vacuum pan150in the Z-axis direction, thereby eliminating the need for an additional adjusting plate and the step of welding said adjusting plate to the assembly990in-situ. If desired, the cam170may be fixed in 6 degrees of freedom relative to the swing arm140by one or more retainers164,166located on either side of the cam. As shown, in some embodiments, retainers164,166may comprise threaded lock nuts which engage threads provided to pin165. In other embodiments (not shown), retainers164,166may comprise internal lock washers having biting teeth in the internal diameter surfaces which lock to pin165when axially pressed axially onto pin165. In yet even other embodiments, retainers164,166may comprise small locking detent pins, positive lock pins, or set screws which transversely engage the pin165.

In use, an operator inputs a torque on the torque boss171, which in turn rotates cam170about pin165. Outer peripheral surfaces of cam170ride/slide along mount157, which acts as a “follower”. As cam170is rotated, pan150moves up or down in a Z-axis direction, thereby increasing or decreasing a distance between the belt910and the adjustable vacuum pan assembly190. Once the desired position of the adjustable vacuum pan assembly190is set in the Z-axis direction, the spacing between belt910and wear plate159can be reversibly set in place by engaging a locking member169with one of the engagement surfaces178provided on the cam170. Engagement surfaces178are preferably marked with indicia to indicate factory set points and indicate an amount of adjustment (e.g., in millimeters). This eliminates the need for a maintenance worker to go through several step iterations to realign the vacuum pan150following routine maintenance or disassembly.

In the particular embodiment shown, engagement surfaces178are apertures which are configured to receive a locking member169in the form of a pin. At least one oblong opening167may extend longitudinally in a Y-axis direction in a median/sagittal Y-Z plane. Locking member169may extend through said oblong opening167and thereby hold cam170against rotational freedom about pin165. Securement of locking member169may be facilitated by a retainer162provided on both an inside portion of bracket160, and an outside portion of bracket160, wherein the retainers162communicate with the locking member169and sandwich the oblong opening167and cam170therebetween. Consequently, pan150may be propped up to a desired elevation with respect to the belt910in at least a Z-axis direction.

The elongated nature of the one or more oblong openings167allows cam170to be fixedly positioned to the bracket160in a plurality of rotational angles utilizing a “peg-in-hole” configuration. However, while not shown, it is contemplated that oblong opening167, retainer169, and engagement surfaces178may be replaced with other means for securing against rotation of the cam170about pin165, including, but not limited to: pawl and ratchet systems, worm drives (e.g., wherein peripheral cam surfaces are toothed), clamp members, and/or semi-permanent tack welds or other form of reversible or temporary adhesive bonding. While specifically shown as clips, it should be noted that retainers162according to the invention may be of any suitable type including, but not limited to: headed rivets, clevis pins, set screws, and the like.

Once the Z-axis position of the pan150is set by cam170and fixed by locking member169, fastener153may be fully tightened or otherwise engaged to further secure the pan150to the swing arm140in at least a Z-axis direction. However, prior to setting fastener153, small horizontal positional adjustments of the vacuum pan150relative to belt910may be made by loosening fasteners153,163and subsequently sliding bracket160along the swing arm140in the X-axis direction, wherein the fasteners163,153slide in oblong openings142,143, respectively. The bracket160and pan150may then be fixed into place with respect to the swing arm140by tightening fasteners153,163.

Alternatively, and more preferably, horizontal positional adjustments of the vacuum pan150relative to belt910may be made by loosening fastener153and subsequently sliding pan150along the swing arm140in the X-axis direction to a desired location, wherein the fasteners153slide in oblong openings143of the swing arm140. Securement of the pan150with respect to the swing arm140begins by tightening fasteners163so as to secure bracket160to swing arm140. Retainers164.166provided on pin165which extends from the bracket160are positioned along the pin165in an X-axis direction so as to move cam170laterally against stop154. Forces acting in the X-axis direction are applied to the stop154by the cam170and move or bend the pan150into longitudinal alignment with pores912in the belt910. The Z-axis position of the pan150may then be set by rotating cam170about pin165to a desired location, and then fixing the rotational position of cam170with locking member169. Thereafter, fastener153may be fully tightened or otherwise engaged to secure the pan150to the swing arm140in at least a Z-axis direction.

A contractor or other entity may provide a belt filter, vacuum pan assembly, or component of vacuum pan assembly, or operate a belt filter or vacuum pan assembly in whole, or in part, as shown and described. For instance, the contractor may receive a bid request for a project related to designing or operating a belt filter or vacuum pan assembly, or the contractor may offer to design such a system or a process for a client. The contractor may then provide, for example, any one or more of the devices or features thereof shown and/or described in the embodiments discussed above. The contractor may provide such devices by selling those devices or by offering to sell those devices. The contractor may provide various embodiments that are sized, shaped, and/or otherwise configured to meet the design criteria of a particular client or customer. The contractor may subcontract the fabrication, delivery, sale, or installation of a component of the devices disclosed, or of other devices used to provide said devices. The contractor may also survey a site and design or designate one or more storage areas for stacking the material used to manufacture the devices, or for storing the devices and/or components thereof. The contractor may also maintain, modify, or upgrade the provided devices. The contractor may provide such maintenance or modifications by subcontracting such services or by directly providing those services or components needed for said maintenance or modifications, and in some cases, the contractor may modify a preexisting conventional filter, vacuum pan assembly, or parts thereof with a “retrofit kit” to arrive at a modified filter system comprising one or more method steps, devices, components, or features of the systems and processes discussed herein.

Although the invention has been described in terms of particular embodiments and applications, one of ordinary skill in the art, in light of this teaching, can generate additional embodiments and modifications without departing from the spirit of or exceeding the scope of the claimed.

For example, it is envisaged that swing arm140and corresponding vacuum pan150may comprise different shapes and sizes depending on the overall size and design specifications of a filter900. Moreover, while oblong openings142,143,156,167are primarily shown in the drawings as through holes, oblong openings may be blind openings and/or may comprise any one or more of the following without limitation: cutouts, a series of closely-spaced non-oblong apertures (threaded or non-threaded), notches, detent configurations, pockets, pawl and ratchet adjustment mechanisms, grooves, channels, depressions, dovetails, and/or undercuts. Similarly, male members shown herein such as locking member169may comprise threads, for example, in the form of a set screw.

Furthermore, features and components of the adjustable vacuum pan assembly190may be modular, removable, “bolt-on”, or “weld-on” components which are provided individually or collectively within a “retrofit kit”. Such components may therefore be interchanged with or added to preexisting conventional vacuum pan assemblies990to achieve the benefits of the invention. In some instances, a retrofit kit may comprise one or more mounts157or adapters to accommodate preexisting conventional mounts957. Said adapters can be bolted or welded to preexisting conventional mounts957or other portions of a preexisting conventional vacuum pan950. Such adapters may comprise one or more stops154, additional flanges or flange extenders, extension members, spacers, or one or more universal mounting features such as oblong openings156which are configured to accept at least one fastener153.

It should be known that in some embodiments, torque boss171may be eliminated in favor of other means for applying a torque to the cam170. Such means may comprise, for instance, torque-application surfaces provided as one or more “flats” which are located at selected peripheral locations of the cam170. Such means may also comprise a lever or handle which extends from the cam, or a peripheral cavity which is engagable by a separate torque arm or cheater bar.

It is contemplated that in some embodiments, male and female components disclosed herein may be reversed and still be within the scope of the disclosure. For example, male pin165provided to bracket160and female aperture provided to cam170may be reversed so that the pin164extends from the cam170and into the bracket160. Similarly, while engagement surfaces178are shown to be provided on the cam170, and oblong opening167is shown to be provided on the bracket160, the two may obviously be reversed such that the engagement surfaces are provided on the bracket160, and oblong opening167is provided on the cam170.

Moreover, the joining of fasteners153,163may be accomplished using threaded connections, plastic deformation, welding, gluing, combinations thereof, or other equivalent means without limitation. Mounts157and/or fasteners153,163may be provided in any number or configuration which is suitable for the intended purpose. As shown inFIGS. 7-8, brackets160according to the invention may further comprise one or more wear belt guides180—each having one or more rollers or bearing members182provided thereon to provide support and/or lateral guidance for a wear belt (not shown) which travels within upper grooves formed in wear plate159and contacts belt910.

Furthermore, the number and configuration of components described may vary. For instance, while two cams170are shown inFIGS. 4-8, a single cam170or more than two cams170may be employed without departing from the scope of the invention. Moreover, while cams170are shown to be mounted to the swing arm140, they may inversely be connected to mounts157, wherein peripheral surfaces of the cam170engage a portion of the swing arm140to effectively vary a spacing therebetween. Alternatively, cams170may be provided to the swing arm140directly, without the need for a bracket160. This may be accomplished, for example, by orienting the cam170ninety degrees from what is shown in the drawings, so that it is parallel to the swing arm140, providing pin165directly to the swing arm140—on which the cam170rotates, and providing a locking member169which engages or otherwise communicates with the swing arm140to prevent rotation of the cam170relative to the swing arm140.

In some instances, swing arm140may comprise a portion of a linkage (e.g., of the four-bar type), which moves pan150up and down in a Z-axis direction. Or the swing arm140may be configured to “tilt” or pivot with respect to the belt910and travel in an arcuate transverse path as shown. Additionally, bracket160may be mounted to other types of vacuum pan150raising and lowering systems such as those disclosed in U.S. Pat. No. 4,336,139, U.S. Pat. No. 4,080,298, U.S. Pat. No. 3,992,298, and U.S. Pat. No. 4,671,876. In some instances, swing arm140may not necessarily be configured to “swing” at all. In other words, it is envisaged that an “arm”, where the term is used herein, may simply comprise a static portion of a filter's frame930, or may comprise an arm140which is connected at both ends to other frame portions930. Such connections may be realized using welding, bolting, or adjustable mounting means. The arm140may also be moved linearly in a Z-axis direction with respect to said belt910without swinging, for example, via the use of one or more mechanical actuators, compressible or incompressible fluid cylinders, or electric solenoids. In some embodiments, arm140may ride on a track, and cams170may be fixed to frame portions930which are adjacent to end portions of the arm140. Z-axis positioning and tilt of the arm140with respect to frame930may be adjusted by rotating and then subsequently immobilizing the cams170relative to the frame930using a locking member169.

It should also be noted that while shown specifically on a horizontal belt filter900, adjustable vacuum pan assemblies190of the invention may be used in other applications requiring quick fine adjustment between two adjacent components. For example, assemblies190and components thereof which are shown and described herein may have equal applicability on table filters and belt filter presses.

Accordingly, it is to be understood that the drawings and descriptions herein are proffered by way of example to facilitate comprehension of the invention and should not be construed to limit the scope thereof.

REFERENCE NUMERAL IDENTIFIERS