A vibratory screening machine and an exciter module
Patent Information
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2024-07-15
- Publication Date
- 2026-03-25
Smart Images
Figure AU2024050756_06032025_PF_FP_ABST
Abstract
Description
[0001] A VIBRATORY SCREENING MACHINE AND AN EXCITER MODULE
[0002] Technical Field
[0003] This disclosure relates to vibratory screening machines and to exciter assemblies used in vibratory screening machines.
[0004] Background to the Disclosure
[0005] Screening is the practice of taking granulated or crushed bulk material and separating it into multiple grades by particle size. The mining and mineral processing industry uses screening for a variety of processing applications. For example, after mining ore, the ore material may be sorted on a shaker screen before being fed into a primary crusher. After crushing the material can pass through a series of screens with openings or slots that progressively become smaller.
[0006] A screening machine consists of a drive system that induces vibration, a screen media that causes particle separation, and a deck which holds the screen media. The deck serves to transit the vibratory movement of the drive system to the screen media.
[0007] The drive system of a screening machine may be provided in the form of an exciter. An exciter usually takes the form of a rotating shaft which carries an eccentric weight. The deck often has two sidewalls, one located on either side of the screen media. An exciter may be mounted in each sidewall of the deck of a screening machine, and the rotatable shafts of the exciters are joined by a common shaft which extends across the deck, to synchronise the rotation of the shafts.
[0008] Sidewall mounted exciter modules used for screens have historically been of three types: (1) A single cantilevered eccentric mass on the side of the exciter that is external to the screen. This design induces large bending moments in the exciter and the sidewall due to the unbalanced nature of the weight arrangement. Substantial internal structural members are then required in order to resist this bending moment and avoid high sidewall stresses and large deformations.
[0009] (2) An unbalanced shaft that spans between bearing houses mounted to each side of the screen as described in US patent 2,349,778. This solution improves balance but requires an extremely heavy shaft, is difficult to maintain, and typically requires a substantial external tube structure to tie the pair of bearing housings together.
[0010] (3) Exciter modules similar to item 1 but with a second of eccentric masses per module on the side of the exciter that is internal to the screen. The exciter module is mounted to the sidewall of the screen by way of a lap j oint connection between the exciter and the sidewall. However, such designs have been found to induce large bi-moments at the exciter flange to sidewall connection requiring heavy structural elements to resist the induced bending forces and to avoid large structural deformations.
[0011] There remains a need for improved screening machines.
[0012] Summary
[0013] In a first aspect the disclosure provides an exciter module for a vibratory screening machine. The vibratory screening machine includes at least two sidewalls and a screening region therebetween. The exciter module includes at least one rotatable shaft for carrying an eccentric weight, and a body surrounding at least a portion of the shaft. An outwardly extending central flange circumscribes a midportion of the body and defines an inner portion of the shaft and an outer portion of the shaft. The eccentric weight includes a first eccentric weight positioned on the inner portion of the shaft, and an equal second eccentric weight positioned on the outer portion of the shaft. The exciter module includes a clamping arrangement for attaching the exciter module to the vibratory screening machine. The clamping arrangement includes first and second clamping plates positioned on either side of the flange and arranged to receive a sidewall in line with the flange so that in use centrifugal forces generated by the exciter module act in a plane coplanar with the mid-plane of its associated sidewall.
[0014] The clamping arrangement may include a spacer plate positionable between each clamping plate and its associated sidewall.
[0015] The first and second clamping plates may be secured to each sidewall by fasteners, or bolts which pass through both of the clamping plates and its respective sidewall.
[0016] In a second aspect, the disclosure provides a vibratory screening machine including at least two sidewalls, each sidewall having a first side and a second side and a screening region comprising one or more screens which is located between the sidewalls. At least two exciters are mounted in an aperture provided in each of the sidewalls. The exciter modules each include at least one rotatable shaft which carries an eccentric weight. Each exciter module is mounted in an aperture provided in each of the sidewalls at a location where the net centrifugal forces generated in use by each exciter module act in a plane that is coplanar with the mid-plane of its associated sidewall. Each exciter module is connected by a balanced intermediate shaft. First and second clamping arrangements are provided to affix the exciter module in relation to its sidewall, wherein the clamping arrangements are provided at the respective first and second sides of each sidewall.
[0017] Each exciter module may include a body and a central flange circumscribing a midportion of the body and defining respective inner and outer portions of each shaft.
[0018] Each clamping arrangement includes first and second clamping plates securable on either side of the central flange and arranged to affix the exciter module in relation to its associated sidewall, wherein the clamping plates are provided at respective first and second sides of each sidewall. The first and second clamping plates may be secured to each sidewall by fasteners, or bolts which pass through the clamping plates, the exciter flange, and each respective sidewall.
[0019] Each clamping arrangement may include a spacer plate which is located between each clamping plate and the central flange.
[0020] Brief Description of the Drawings
[0021] An embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:
[0022] Figure 1 is a perspective view of a vibratory screening machine;
[0023] Figure 2 is a detailed view in the region of an exciter module of the machine of figure 1;
[0024] Figure 3 shows the exciter module of figure 2 with protective guard removed;
[0025] Figure 4 is a reverse cut-away view of the machine of figure 1;
[0026] Figure 5 is a partial section view of the exciter module of figure 2 installed in a sidewall;
[0027] Figure 6 shows the exciter module of figure 2 shown in isolation of the machine along with clamping plates;
[0028] Figure 7 is a cross sectional view of the exciter module of figure 6; Figure 8 is a perspective view of an alternative embodiment of a vibratory screening machine;
[0029] Figure 9 is a detail view of an exciter module of the machine of figure 8 with protective guard removed;
[0030] Figure 10 is a reverse cut-away view of the machine of figure 8;
[0031] Figure 11 is a side view of the exciter module of figure 9;
[0032] Figure 12 shows the exciter module of figure 9 shown in isolation of the machine along with clamping plates and spacer plates; and
[0033] Figure 13 is a cross sectional view of the exciter module of figure 12.
[0034] Detailed Description of the Preferred Embodiment
[0035] Referring to figure 1, a vibratory screening machine 10 for classifying bulk materials is shown which includes a deck having sidewalls 12 and 14, each of the sidewalls has a first outer side and a second inner side. A screening region is provided between the inner sides of the sidewalls and is comprised of four screens 15a through 15d. It is also possible to have more than two sidewalls. For example, there may be three sidewalls with two screening regions. Each of the screens includes screen media with progressively smaller apertures. An exciter in the form of exciter module 20 is mounted in an aperture provided in sidewall 14. Another similar exciter module 20b (not visible in figure 1) is mounted in the opposite side wall 12.
[0036] Referring to figure 2, exciter module 20 includes a guard 22 and a shaft 24. The shaft 24 includes a motor engagement formation in the form of stub axle 25 to which the output shaft of a motor (not shown) is attached in use to rotate the shaft 24. Referring to figure 3, the exciter module 20 is shown with guard 22 removed to reveal a set of four eccentric weights 26 which are mounted on the shaft 24. Figure 3 shows all four eccentric weights 26 in aligned position. The weights may be adjusted (see figure 7) to allow the force generated by the exciter module 20 to be modified for different operational requirements. The exciter module 20 includes a body 29 having an axially extending sidewall 28 and a radially extending central flange 34 (Figure 7) extending from a midportion of the body 29. The flange 34 circumscribes, or extends around, the body 29 of the exciter module 20 and defines an inner portion and an outer portion of the shaft 24. The shaft 24 is mounted in bearings which are housed in the body
[0037] 29 of the exciter module 20. A clamping arrangement is used to attach the exciter module 20 to the sidewall 14. The clamping arrangement includes a set of outer clamping plates
[0038] 30 and an outer spacer plate 32. The clamping arrangement further includes inner clamping plates 30a and an inner spacer plate 32a (these are not visible in figure 3). The inner and outer spacer plates 32, 32a also serve the function of providing stiffening around the region of the sidewall 14 where the exciter module 20 is mounted.
[0039] Referring to figure 4, exciter module 20 has an identical set of four weights 26a mounted on a portion of shaft 24 which emanates from the other side of the body 29 as seen in figure 3. The weights 26 are balanced with the weights 26a. The weights 26, 26a are of the same dimensions and masses, and are mounted in the same angular orientation on shaft 24. The inner clamping plates 30a and inner spacer plate 32a are visible in this figure.
[0040] Another exciter module 20b is located in an aperture in the opposite sidewall 12. Exciter module 20b is fitted to the sidewall 12 in the same manner as exciter module 20 and is identical in construction except for the omission of stub axle 25. The shaft 24b of exciter module 20b is joined to the shaft 24 of exciter module 20 via an intermediate shaft 40 so that their respective sets of weights are in the same angular orientation. Intermediate shaft 40 is a balanced shaft. Drive force applied to stub axle 25 drives both exciter assemblies 20, 20b in unison. Referring to figure 5, exciter module 20 is shown in association with sidewall 14. In order to attach the exciter module 20, the inner and outer spacer plates 32, 32a are first attached to the sidewall 14. The inner and outer spacer plates 32, 32a have an outer series of bolt holes and an inner circle of bolt holes. The outer series of bolt holes can be seen in figure 3. The spacer plates 32, 32a are attached to the sidewall 14 by securing nuts and bolts through the outer series of bolt holes, and through a corresponding series of holes provided in the sidewall 14. The spacer plates 32, 32a have an aperture which corresponds to the shape of the aperture provided in the sidewall 14.
[0041] The exciter module 20 is then introduced to the aperture in the sidewall 14, and the inner and outer clamping plates 30, 30a are affixed. The clamping plates 30, 30a have an inner series of bolt holes and an outer series of bolt holes as best seen in figure 6. Bolts are secured with nuts through both series of holes. In the outer series of holes the bolts pass through the clamping plates 30, 30a, the spacer plates 32, 32a, and the sidewall 14. In the inner series of holes the bolts pass through the clamping plates 30, 30a and the flange 34 which circumscribes, or extends around, a midportion of the outer circumference of the centre of the body 29 of the exciter module. The flange 34 is best seen in figure 7.
[0042] Referring now to figures 6 and 7, shaft 24 is housed in body 29 by a pair of bearings 36 separated by a spacer 38. The bearings are secured inside body 29 by end cap 33. Before use, the inside of the body 29 is partially filled with oil to lubricate the bearings. The oil filled cavity can equalise with atmospheric pressure through breather hole 31.
[0043] The weights 26, 26a on either side of the exciter 20 are balanced. That is to say that they are of the same dimensions and masses, are in the same angular orientation and are located the same distance away from the mid-point of the flange 34. This means that in use, when the exciter module 20 is rotating, net centrifugal forces generated are in a plane that is located at the mid-point across the width of the central flange 34. This allows the exciter 20 to transfer the generated force directly into the side wall 14 without introducing any bending loads.
[0044] When installed in the aperture in the sidewall 12, 14, the sidewall is aligned with the flange 34. This means that the centrifugal forces generated by each exciter module 20 act in a plane that is coplanar with the sidewall 12, 14. That is, the plane in which the net centrifugal force of the exciter acts is located between the inner and outer faces of the sidewall to which it is attached.
[0045] In addition, the clamp plates 30 are provided at both sides of the sidewall and have a clamping effect at each side of the flange of the exciter module 20. The clamping effect forms a symmetrical joint avoiding stresses caused by twisting or bending.
[0046] Referring now to figures 8 to 13, a second embodiment of a screening machine 100 is shown. This machine is similar in construction to machine 10 and like reference numerals in the series 100 will be used to denote like components. Machine 100 differs from machine 10 in that is uses dual shaft exciter modules 120.
[0047] Dual shaft exciters have identical sets of weights mounted on two shafts (see 124, 124a in figure 9). The shafts are geared together to rotate in opposite directions in a 1 : 1 ratio. As is known in the art, the angular orientation of the weights on the shafts can be adjusted to generate a variety of sinusoidal movements by the screening machine. The sinusoidal movement can be controlled to create movement of the bulk material along the machine as it passes along and through the screens 115a, 115b, 115c.
[0048] Again, as seen in figure 10, two exciter modules 120, 120b of identical construction are located in apertures in opposite sidewalls 112, 114. The exciter modules are joined by a drive shaft 140 and drive is applied to stub axle 125.
[0049] As best seen at figures 12 and 13, a first clamping arrangement comprising clamp plates 130 and spacer plate 132 is provided at the outside of sidewall 114 and a second clamping arrangement comprising clamp plates (not shown) and spacer plate 132a is provided at the inside of side wall 114.
[0050] Fasteners such as nuts and bolts are used to attach the exciter assemblies 120 using the clamping plates 130, 130a and spacer plates 132, 132a in the same manner as described for machine 10 above. As best seen at figure 13, the sidewall can be accommodated in the space between the spacer plates 132, 132a so that when installed the outer flange 134 of the housing of the exciter assembly 120 is aligned with the sidewall. This means that the centrifugal forces generated by each exciter assembly 120, 120b act in a plane that is coplanar with its respective sidewall. That is, the plane in which the net centrifugal force of the exciter acts is located between the inner and outer faces of the sidewall.
[0051] With the arrangements described above, there are no bending moments or bimoments set up at in the region of the junction between the exciter assembly and the sidewall. This reduces stress / strain fatigue in the sidewall and the exciter assembly itself. Not only does this improve the life expectancy of the machine, but it allows for use of less material in fabricating the parts of the machine. It is estimated that a weight saving of up to 13% of the weight of the machine can be achieved. This weight saving is very significant in a vibrating machine because the mass of the machine contributes to the energy consumption of the machine in use. A lighter machine is more efficient in operation because there is less extra mass to vibrate.
[0052] Invention(s) have been described in connection with what are presently considered to be the most practical and preferred embodiments, it is to be understood that the invention is not to be limited to the disclosed embodiments, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the invention(s). Also, the various embodiments described above may be implemented in conjunction with other embodiments, e.g., aspects of one embodiment may be combined with aspects of another embodiment to realize yet other embodiments. Further, each independent feature or component of any given assembly may constitute an additional embodiment. List of Parts
[0053] Vibratory screen 10, 100
[0054] Sidewall 12, 112
[0055] Sidewall 14, 114
[0056] Screens 15a-15d, 115a-115d
[0057] Exciter module 20, 20b, 120, 120b
[0058] Guard 22, 122
[0059] Shaft 24, 124, 124a
[0060] Stub axle 25, 125
[0061] Weights 26, 26a, 126
[0062] Weights 127
[0063] Body 29, 129, 129b
[0064] Clamping plates 30, 30a, 130, 130b
[0065] Breather hole 31
[0066] Spacer plates 32, 32a, 132, 132a
[0067] End cap 33
[0068] Central flange 34, 134
[0069] Inner portion of shaft 35
[0070] Bearings 36
[0071] Outer portion of shaft 37
[0072] Spacer 38
[0073] Intermediate Shaft 40, 140
Claims
Claims:
1. An exciter module for a vibratory screening machine having at least two sidewalls and a screening region therebetween, the exciter module including: at least one rotatable shaft; a body surrounding a portion of the shaft, a central flange circumscribing a midportion of the body and defining an inner portion of the shaft and an outer portion of the shaft; a first eccentric weight positioned on the inner portion of the shaft, and an equal second eccentric weight positioned on the outer portion of the shaft; and a clamping arrangement for attaching the exciter module to the vibratory screening machine, wherein the clamping arrangement includes first and second clamping plates positioned on either side of the central flange and arranged to receive a sidewall in line with the central flange so that in use centrifugal forces generated by the exciter module act in a plane coplanar with the mid-plane of its associated sidewall.
2. The exciter module of claim 1, wherein the clamping arrangement includes a spacer plate positionable between each clamping plate its associated sidewall.
3. The exciter module of claim 1 or 2, wherein the first and second clamping plates are secured to each sidewall by fasteners which pass through the clamping plates, the central flange, and each respective sidewall.
4. A vibratory screening machine including: at least two sidewalls, each sidewall having a first side and a second side and a screening region comprising one or more screens which is located between the sidewalls; at least two exciter modules connected by a balanced intermediate shaft, each exciter module including at least one rotatable shaft which carries an eccentric weight; andfirst and second clamping arrangements provided at respective first and second sides of each sidewall for affixing the exciter module in relation to its sidewall, wherein each exciter module is mounted in an aperture provided in each of the sidewalls at a location where the net centrifugal forces generated in use by each exciter module act in a plane that is coplanar with the mid-plane of its associated sidewall.
5. The vibratory screening machine of claim 4, wherein each exciter module includes a body and a central flange circumscribing a midportion of the body and defining respective inner and outer portions of each shaft.
6. The vibratory screening machine of claim 5, wherein the eccentric weight includes a first eccentric weight positioned on the inner portion of each shaft and an equal second eccentric weight positioned on the outer portion of each shaft.
7. The vibratory screening machine of any one of claims 4 to 6, wherein each clamping arrangement includes first and second clamping plates securable on either side of the central flange and arranged to affix the exciter module in relation to its associated sidewall, wherein the clamping plates are provided at respective first and second sides of each sidewall.
8. The vibratory screening machine according to claim 7 wherein the first and second clamping plates are secured to each sidewall by fasteners which pass through the clamp plates and the respective sidewall.
9. The vibratory screening machine according to any one of claims 4 to 8, wherein each clamping arrangement includes a spacer plate which is located between each clamping plate and the sidewall.