NZ627566B2 - An improved belt scraper mounting - Google Patents

Abstract

improved belt scraper mounting for belt conveyors (10) having conveyor frame / stringer, comprising : a scraper blade module assembly (3) and a means (1, 2, 4) for holding said blade module assembly with said conveyor frame / stringer on both sides of said belt scraper, said means being adapted to function in an auto adjusting mode. The upper spring (1) has greater strength than the lower spring (2). Auto adjustment allows for the scraper to minimize necessary force on blade and results in less frequent changing of blade. o function in an auto adjusting mode. The upper spring (1) has greater strength than the lower spring (2). Auto adjustment allows for the scraper to minimize necessary force on blade and results in less frequent changing of blade.

Description

AN IMPROVED BELT SCRAPER NG 5 FIELD OF THE INVENTION The t invention in general relates to belt scrapers for its application in bulk material handling belt conveyors and in ular, to an improved belt scraper mounting with sed cleaning ‘l0 efficiency, which is easy to install and possess auto adjustment ism, requires no maintenance for a long period and has reduced operational and cleaning cost.

BACKGROUND OF THE INVENTION [5 Belt rs are used in bulk material handling belt conveyors to avoid material carry back, reduce spillage and keep belt clean. Clean belts help prevent material build up on snub pulley and return rollers and increase its life, thereby reducing cleaning cost, downtime cost 20 and mis—tracking of the belt.

In first generation Counter weight belt scraper, single blade design is made from thickrubber strip (wider than belt width) under the return belt and the counter weight provided at the side of the belt scraper with a pivot point to. provide contact with the belt. The initial load 25 exerted to the belt is approximately 80 ~ 90 Kgs. With time when the' ng effectiveness reduces, the weight is increased and it can go up to 150 Kgs.

Cleaning efficiency is approx 60—68 % and always, it is needed to, increase counter weight load on a regular basis against blade wear. It J 14 h. V is very less effective and high maintenance is involved.

‘ Second generation fixed mount belt scraper’s segmented blades module are made of hard alloy steel with rubber cushion at the bottom of blade mounted on a steel tube with both end fixed mount. It does not have automatic adjustments against blade wear. It provides istent contact pressure to the belt which is imately 100 - 125 Kgs.

Cleaning efficiency is approx 70-85 % and , there is need to liftv up of the fixed mount on a regular basis against blade wear. It is less ive and high maintenance involved. l0 Pneumatically operated third generation belt scraper having segmented blades module are made of hard alloy steel with or without polymer cushion at the bottom mounted of blade on a steel tube with ratchet and pinion mount and adjustment done h compressed air at 7—10 bars pneumatically. They provide inconsistent load to the belt of approximately 90 — 110 Kgs.

Cleaning efficiency is approx 75-85 %. There is a need to pump air periodically to maintain the blade to belt contact clue to drop in air pressure / leakage / ng of air. Maintenance requirement is high.

In fourth generation belt scrapers with shock absorber which acts as 20 semi automatic adjustments to some extent but, there is a need for periodic manual adjustments against blade wear in every 3 - 4 weeks interval. This type of belt scrapers have segmented type metallic blades module with pivot point below the scraping edge mounted on a steel tube with both ends rubber shock er. It provides comparatively less load to the belt, which is approximately 24 — 80 Kgs.

Cleaning efficiency is approx 92—95 %. It provides less consistency against heavy duty, high vspeed, vibration and bi—directional belt operation.

Accordingly there was a long felt need to design belt scraper mountings which are maintenancefree and long lasting and Facilitates automatic adjustment in the field of bulk material handling conveyor systems to meet the increasing belt capacity (tonnages), higher belt . speed and heavy duty of belt with wider belt conveying system.

The present invention meets the aforesaid long felt need. l 0 All through out the specification including the claims, the words “conve I! ‘\ or belt", “scra er blade scra er holdin arm” “5 rin ” I g I “washer", “stud”; and “nut" are to be interpreted in the st sense of the respective terms and includes all similar items in the field known by other terms, as may be clear to persons skilled in 'the art.

Restriction / Limitation if any, referred to the specification, is solely by way of example and understanding the present invention.

S OF THE INVENTION 20 It is the principal object of the present ion to provide an improved belt scraper mounting which is maintenance free and provide long lasting cleaning efficiency & facilitates automatic adjustment in the field of bulk al handling conveyor s to meet the increasing belt capacity (tonnages), higher belt speed and duty of belt to Ln with wider belt ing system.

It is r object of the present invention to provide an improved belt scraper mounting system possessing higher efficiency of belt cleaning ed to the contemporary belt scrapers.

It is yet another object of the present invention to e an improved belt scraper mounting system which provides easy and flexible installation.

It is a further object of the present invention to provide an improved belt scraper mounting which provides auto adjustment mechanism and compensate the need of varying loads to maintain contact with the belt.

IO It is a further object of the t invention an improved belt scraper mounting system which requires tely no nance for a very long period.

It is another object of the present ion to provide an improved i belt scraper mounting system possessing reduced operational and cleaning cost.

It is another object of the present invention to provide an improved belt scraper mounting system which possesses & confirmed precision belt cleaning.

It is yet another object of the present invention to provide an improved belt scraper mounting system which completely eliminates sagging of scraper assembly permanently and confirmed ion belt cleaning 25 continuously.

It is another object. of the present invention to provide an improved belt r for its ation in bulk material handling conveyor systems, which is equipped with automatic scraper adjustment against blade wear and does away with the need for manual lifting of scraper fixing mount in an upward direction towards the belt to compensate blade wear.

How the foregoing objects are achieved and the other aspects of the. t invention will be clear from the following description which is purely by way of understanding} and not by way of any sort of limitation.

SUMMARY OF THE INVENTION Accordingly, the present invention provides an ed belt scraper V l, O mounting for belt conveyors having conveyor frame / stringer, sing : a scraper blade module assembly and a means for holding . said blade medule assembly with said conveyor frame / stringer on both sides of said belt scraper, said means being adapted tofunction in an auto adjusting mode.

In accordance with preferred ments of the belt scraper mounting of the present invention: -said means comprises of an upper dynamic spring adjuster andga lower dynamic spring adjuster; —said belt scraper works in the range from 300 mm and 3200 mm of belt width and said upper dynamic spring adjuster and said lower dynamic spring adjuster together constitute a dynamic auto ing 25 r fixing mount; said upper and lower dynamic spring adjuster are operatively adapted ' to be ted with a scraper holding arm through a long stud, said blade module assembly being mounted on said scraper holding arm and said scraper holding arm being kept in position by means of a step washer; said auto adjusting mount comprises of a pair of helical springs in which said lower spring has higher suspension stability than said upper spflng; -said dynamic auto adjusting scraper fixing mount is adapted to hold a circular tube scraper blade module assembly; —said dynamic auto adjusting scraper fixing mount is adapted to hold a square / rectangular / triangular or any other cross~section tube 10 scraper blade module assembly; -one helical spring is placed above said scraper holding arm and another helical spring is placed below said r g arm and are kept in position by means of washer and nut arrangement. —said nut arrangement comprises shoulder nuts adapted to be ssed by 30 mm in either direction, so as to ensure stability against belt velocity / ion cleaning.

The present invention also provides a method for applying a belt scraper for bulk material handling belt conveyors having conveyor frame / stringer, in the manner such as herein described, a scraper blade module assembly and a means for holding said blade module assembly with said conveyor frame / er on both sides of said belt scraper, said. means being adapted to function in an auto ing mode.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS The nature and scope of the t invention will be better understood from the accompanying drawings, which are by way of illustration of some preferred embodiments and not by way of any sort of limitation. In the accompanying drawings, Figure 1 illustrates a perspective view of the improved belt r mounting in accordance with a preferred embodiment of the present invention.

Figure 2 illustrates a detailed sectional view of the improved belt scraper mounting according to a red embodiment of the present 10 invention.

Figure 3 illustrates a sectional View of the circular tube scraper blade module assembly holding.

Figure 4 illustrates a sectional view of the square tube scraper blade . moduleassembly holding.

Figure 5 illustrates the method of ion belt cleaning with the improved belt scraper mounting of the present invention. 20 Figure 6 illustrates sagging of belt scraper assembly known in the art.

Figure 7 illustrates the efficiency curve achieved by the improved belt scraper mounting of the present invention.

ED DESCRIPTION OF THE INVENTION The following bes some preferred embodiments of the t invention, which are purely for the sake of understanding the performance of the invention, and not by way of any sort of limitation.

As stated before the present invention primarily aims at ing improved belt scrapers mounting system which is maintenance free and long lasting and facilitates automatic adjustment in the field of bulk material handling or systems to meet the increasing belt capacity (tonnages), higher belt speed and heavy duty of belt with wider belt conveying system.

Belt Scrapers generally consist of two different major parts namely, 10 a) r Blade module Assembly and b) Scraper Fixing Mount. _S_crager Blade modulefissembly: It is mounted on a steel tube by means of nuts and bolts and placed under the belt to touch and clean. the belt e: Scrager Fixing Mount: It holds the scraper blade module assembly against the belt both sides of the tube to the conveyor stringer frame by means of-nuts and bolts. Thus, there is no automatic scraper adjustment against the blade wear hence, always need manual lifting of scraper fixing mount upward ion towards the belt to compensate the blade wear.

In the present invention the existing r fixing mount is replaced by dynamic auto adjusting'mount. This feature is indispensable for the invention.

Figure 1 illustrates a perspective View of the improved belt scraper in accordance with a preferred embodiment of the present invention. The entire belt scraper assembly n the scraper blade module is in contact with the conveyor belt is provided in the said figure. As shown in the figure the scraper holding arm (4) on which .the scraper blade module (3) is mounted and kept in position by a heavy duty upper c spring adjuster (1) iocated above it and another heavy duty lower dynamic spring adjuster (2) located below it.

VI To meet the g market demand of maintenance free and long lasting automatic adjustment of Belt r in the field of bulk als handling conveyor systems and to meet the increasing belt capacity (tonnages), higher belt speed and duty of belt with wider belt conveying , the present invention thus provides an automatic 10 and long lasting vibration and maintenance free belt scraper suspension for the belt width 300 — 3200 mm.

The improved belt scraper tic adjusting mount in the present . invention, primarily consists of: 15 1) Heavy Duty Upper Dynamic Spring Adjuster (1) .2) Heavy Duty Lower Dynamic Spring Adjuster (2) 3) Step Washer (5), Stud (6) and so on as described hereinafter. 20 The accompanying figure 2 illustrates a more detailed nal view of the improved belt scraper mounting showing its different ents as according to a preferred embodiment of the present invention. As shown in the figure the springs (1,2) are kept in position by a couple of flat washers (5,5’) on either side of the spring and tightened by means [\J U! of a lock nut (7,7’) arrangement. The scraper holding arm is kept in position by means of a step washer (8). The springs (1, 2) are affixed - on the conveyor frame by means of a stud (6).

The figure 3 shows a cichlar tube scraper blade assembly, While in figure 4, the same is square. It is to be understood that the dynamic auto adjusting scraper fixing mount of the belt scraper mounting according to the present invention, is adapted to hold a square / 10 rectangular / triangular or any other section tube scraper blade module assembly.

In the present invention the improved belt scraper holds the existing (JV blade module assembly with the conveyor frame / er. The dynamic spring assembly (1,2) with scraper holding arm(4) inserted through a long stud, boost the ng scraper blade module assembly to a new high degree of cleaning efficiency continuously while in touch with the belt surface in suspension / floating condition, even after the l() scraper blades modules gets worn—out. Thus, it delivers vibration free precision belt cleaning for a long period without any manual adjustment / servicing.

Design Calculations involved in said improved belt scraper as according '15 to the present invention with a few hypothetical parameters ’is illustrated as s: Load Calculation for 1000 mm Belt Width Scraper (Material Specification: EN 45).

Force (F) 2 Load due to scraper assembly weight + Load due to belt velocity + Load due to pressure given by the blade + Load of upper , 25 F=(F1+F2+F3+F4) F1=(45—2x6.1)x9.81=322 N.

F2 2 (Power transmitted by the motor/ Belt velocity) C0560 X C0530.

F3=8x5x9.81=393N.

F4 = Max.1800 N der as per design).

So, F = (322 + F2 + 393 + 1800) = (2515 + F2) N, Lower Spring Calculation: Let consider, W = Design the spring at max. load of 5000 N [for Safety 40 Purpose]. 11 Free Length Of Spring = 130 mm.

Length at Full Load = 100 mm.

Inner Dia. of Spring = 45 mm.

Shear Stress = 8 x F x D/3.14d’\3 [Allowable Shear Stress = 450 ‘ N/mmA2] ‘d = 10.74 mm.

Spring Index (C) = 5.18 10 Wahl's Correction Factor (K) = (4C—1)/ (4C-4) + 0.615 / C = 129 ore, Modified Wire Dia, Shear Stress = K x 8 x W X D/3.14d"3 d = 12 mm.

Total Deflection = 8 x W x CA3 x N / G x d ulous of Rigidity=84GPa, N=7]:‘:~ = 30 mm.

Spring Constant = 5000/30 = 167 N / mm. ggger Spring Calculation: Lets consider, W 2 Design the spring at max. load of 2700 N [for Safety Purpose]. ' Free Length of Spring 2 80 mm Length at Full Load = 50 mm.

Inner Dia. of Spring 2 45 mm. 30 Shear Stress = 8 x F x D/3.14d"3 [Allowable Shear Stress = 450 ' N/mmAZ] d = 8.75 mm.

Spring Index (C) = 6.14 35 Wahl's Correction Factor (K) = (4C—1)/(4C—4) + 0.615 / C = 1.246 Therefore, Modified Wire Dia, ‘ Shear Stress = K x 8 x W x D/3.14d’\3 40 d = 10 mm.

Total Deflection = 8 x W x CA3 x N / G x d [GzModulous of Rigidity=84GPa, N=5] = 30 mm.

Spring Constant = 2700/ 30 = 90 N / mm. 12 Suspension Stability of Spring for 1000 mm Belt Width Scraper: Downward Force Given by Upper Spring (M) = 90 x 22 = 1980 N.

[Upper Spring Compression is 22 mm]. .

I LI rd Force by Belt Conveyor due to Belt Velocity=(10x10"3/3) Cos 60xCos 30 [Motor 2 10 Kw, Belt Speed = 3 m/sec] : 1445 N .l() Considering, Force Balance on One Side Spring. The above Force to be half of the Total Force.

So, Downward Force by Belt Conveyor due to Belt Velocity (N) = 1445 / 2 == 722 N. [Load of half Scraper Wt = 50 / 2 = 25 Kgs. of 1000 mm B/W] Total Downward Force of Upper Spring (P) = (M + N + O) = (1980 + 722 + 250): 2952 N.

Upward Force given by Lower Spring (Q) = 167 x 14': 2338 N + Load of Rubber Suspension of r [Wt = 125 K95. of1000 mm B/W and Lower Spring Compression is 14 mm] = 2338 + 1250 = 3588 N.

Total Upward Force~ of Lower Spring (Q) = 3588 N. l\'} ’Ji sion Stability of Lower Spring = R = (Q - P) = (3588 '— 2952) i 636 N. .

Therefore, Percentage of Suspension Stability of Lower Spring against 30 Upper Spring 2 (Q — P) / P X 100 % = 21.54 0/o.

The non—limiting ages achieved by the improved belt scraper are as follows: 1. Easy/ Flexible Installation. 2. Auto Adjustment / No Maintenance for a long period (12—16 Weeks min). 40 3. Confirm Precision Belt Cleaning (Clean up~to 0.05—O.1 mm thin layer of carry back). . 4. High Cleaning Efficiency for a long period (12-16 Weeks min). 5. Reduced Operational and Cleaning Cost. 13 6. Presence of automatic adjustment against blade wear does away with the need for normal lifting of scraper fixing mount in . upward direction, towards the belt to compensate the blade U) module wear.

The improved belt scraper mounting is very handy and suitable for all type of belt scrapers replacing the existing fixed mount assembly, . unscrewing the nut/ bolt. Also, it has an option for circular, square, l O rectangular or any other cross—section tube scraper blade module assembly holding facilities as shown in the accompanying figures 3 and 4 respectively.

Automatic Adjustment: As stated before, the improved belt scraper has two c l spring assemblies (1,2) one each is , placed above and below the scraper holding arm with able shoulder nuts (7, 7’) can be compressed by 30 mm max. in either directions and make them stable 20 against belt velocity / precision belt cleaning (Shown in s 1 and 2), _ Since the lower spring having approx 20 0/0 higher suspension stability than upper spring it always keep the scraper blade module (3) in touch with the belt surface (10) automatically, even after the blade module [‘0 (ll wear. Therefore, no maintenance is required for a longer period.

Precision Z High Efficiency Belt Cleaning: The improved belt scraper cleans the belt surface further to a new high degree of precision cleaning ,to remove even nt micro fines materials and moisture from the belt surface: 14 Also, it prevents sagging of existing scraper ly due to its dynamic spring assembiy design. ThLis, ng efficiency increases up to a level of 99.5 % as shown in figure 7.

Figure 5 illustrates precision belt cleaning as performed by the improved belt scraper mounting of the present invention. It shows a - belt scraper blade module assembly fitted with highly wear resistant tip brazed with its supporting base approximately 1mm above for the very minimal frictional contact with the belt surface at an angle against the l0 direction of belt. This ensures sharp and precision cleaning of inherent carry back materials and moisture from the micro contours of the belt surface efficiently. With the help of the improved belt er mounting according to the present invention the blade module tip is kept in position for a longer period ensuring unhindered performance l5 for a substantially long period of time.

Figure 6 illustrates sagging of existing belt scraper assembly. The firmed line specifies the minor sagging of existing belt r assembly by approximately 3 ° two to three weeks after initial installation. This sagging also to be prevented and firmed contact with the belt surface always to be maintained by using c spring mounting assembly. The reference numeral (9) indicates the scraping edge initially after installation. The reference numeral (10) indicates the belt direction. 25 The'dynamic auto ing scraper fixing mount of the belt scraper mounting according to the present invention, is adapted to hold a square / rectangular / ular or any other cross—section tube scraper blade module assembly; 15 Reduced Operational and Cleaning Cost: In the ed belt scraper the cleaning. efficiency is enhanced by 14.5 % also preventing existing scraper assembly sagging, thereby improving productivity and reducing manpower/ maintenance cost.

Figure 7 illustrates the ency curve achieved by the improved belt scraper of the present invention on trial run.. It can be seen that even after eighteen weeks of usage, the efficiency is 98%. Comparatively, on running with 2“d / 3rd generation scrapers, after two weeks, the 10 efficiency has been found to be 75% only as ed to the l efficiency of 85%. With 4th generation scrapers, after 4 weeks the efficiency has been found to 92% from 95% initially.

All blade module assemblies can be directly mounted with the improved n of the belt scraper according to the t IS invention, to achieve tic scraper adjustments with high belt cleaning efficiency, precision belt cleaning of 98-99.S % for a longer period without any maintenance thereby, highly reduced carry back, manpower, downtime and increased productivity / reduced cost. 20 The present invention has been described with reference to some drawings and preferred embodiments, purely for the sake of understanding and not by way of any tion and the present invention includes all legitimate developments within the scope of what has been described hereinbefore and claimed in the appended claims.

Claims (6)

1. A belt scraper mounting for bulk material ng belt conveyors having conveyor frame / stringer, said belt scraper mounting comprising: a scraper blade module assembly and a means for holding said blade 5 module assembly with said conveyor frame / stringer on both sides of said belt scraper, said means being adapted to function in an auto adjusting mode, n said means comprises of an upper dynamic spring adjuster and a lower c spring adjuster, said belt scraper works in the range from 300 mm and 3200 mm of belt width and said upper dynamic spring adjuster 10 and said lower dynamic spring adjuster together tute a dynamic auto adjusting scraper fixing mount, and wherein said auto ing mount comprises of a pair of helical springs in which said lower spring has higher suspension stability than said upper spring. 15

2. The belt scraper mounting as claimed in claim 1 wherein said upper and lower dynamic spring adjuster are operatively adapted to be connected with a scraper holding arm through a long stud, said blade module ly being mounted on said scraper holding arm and said scraper holding arm being kept in position by means of a step washer. 20

3. The belt scraper mounting as claimed in claim 1 wherein said c auto adjusting scraper fixing mount is adapted to hold a circular tube scraper blade module assembly. 2845128v1 17

4. The belt scraper mounting as claimed in claim 1 wherein said dynamic auto adjusting scraper fixing mount is adapted to hold a square / rectangular / triangular or any other cross-section tube scraper blade module assembly.

5. The belt scraper mounting as claimed in claim 2 n one helical spring 5 is placed above said scraper g arm and another helical spring is placed below said scraper holding arm and are kept in on by means of washer and nut arrangement.

6. The belt scraper mounting as claimed in claim 5 n said nut arrangement comprises shoulder nuts adapted to be compressed by 30 mm in 10 either direction, so as to ensure stability against belt velocity / precision cleaning. 2845128v1