Design of Intelligent Belt Conveyor Idler Rolls - Ontwerp van Intelligente Transportbandrollen

Delft University of Technology

FACULTY MECHANICAL, MARITIME AND MATERIALS ENGINEERING

Department Marine and Transport Technology Mekelweg 2 2628 CD Delft the Netherlands Phone +31 (0)15-2782889 Fax +31 (0)15-2781397 www.mtt.tudelft.nl

This report consists of 33 pages and 2 appendices. It may only be reproduced literally and as a whole. For commercial purposes only with written authorization of Delft University of Technology. Requests for consult are only taken into consideration under the condition that the applicant denies all legal rights on liabilities concerning the contents of the advice.

Specialization: Transport Engineering and Logistics

Report number: 2016.TL.8093

Title:

Design of Intelligent Belt

Conveyor Idler Rolls

Author:

J.P.R. Triepels

Title (in Dutch) Ontwerp van Intelligente Transportbandrollen

Assignment: Research project

Confidential: no

Supervisor: Dr. ir. Y. Pang

T

U

Delft

Delft University of Technology Department of Marine and Transport Technology

Mekelweg 2 2628 CD Delft the Netherlands Phone +31 (0)15-2782889 Fax +31 (0)15-2781397 www.mtt.tudelft.nl Student: Supervisor: Specialization: Creditpoints (EC): Joris Triepels Y. Pang TEL 15 Assignment type: Report number: Confidential: Design Assignment 2016.TEL.8093 No

Subject: Design of Intelligent Belt Conveyor I d l e r Rolls

Monitoring the individual idler rollers of large-scale belt conveyors is a challenge. The inspection of idlers by maintenance personnel is traditionally applied to prevent roll failures. Human inspection is considered to be time consuming, labor intensive, costly and unreliable.

With equipped monitoring units such like RFID tags and temperature sensors, the advanced monitoring technology of intelligent idler rolls, in another term of Smart Idlers, is under development in woHd-leading idler manufacturers. More design solutions are pursued with respect to the feasibility of the intelligent rolls in industrial practice, the reliability while cost-effectiveness as well as the capability of energy harvesting for the monitoring units.

This research assignment is to explore the possible design solutions for intelligent idler rolls, which should cover the following:

• to investigate current development of intelligent monitoring for idler Rolls • to review existing design(s) and the relative limitations of intelligent idler rolls • to setup the requirements and criteria for new design

• to provide at least 3 new design solutions for the potential innovation of existing design(s) ® to compare the design solutions and to suggest potential future applications

3D Solidworks models are required as the design tool and to show the design solutions.

This report should be arranged in such a way that all data is structurally presented in graphs, tables, and lists with belonging descriptions and explanations in text.

Summary

Belt conveyors are widely used to transport large volumes of bulk material and as with most mechanical in-stallations, also belt conveyors need to be maintained. Often the belt conveyors are inspected manually by ’walking along the conveyor’. Due to the large scale of many of these installations, this is a labour intensive, costly, unreliable and even dangerous process. The most common reason for maintenance jobs are damaged idler roll, specifically failed bearings of the idler roll. Bad or insufficient maintenance of these rolls can have catastrophic influences.

The industry, as well as Delft University of Technology, is working on the development of advanced moni-toring technology of these idler rolls. Equipped with monimoni-toring units such as RFID tags and temperature sensors these standard rolls become ’Intelligent’ or ’Smart’ rolls. The temperature sensors sense an increase in temperature near the bearings, indicating a potential bearing failure. The combination of this sensor and an active RFID tag (together forming a node) makes it possible to asses the whole belt conveyor from one central location. Information is communicated from node to node using a ZigBee wireless communication network. There are already working examples of the intelligent idler roll. The Transport and Logistics depart-ment at Delft University of Technology has a concept idler roll with a battery as power source. The company Vayeron has also developed a version of the intelligent idler roll equipped with multiple sensors. Besides the in-roll application of sensors, there are more methods of monitoring the idler rolls. For example Intium Solu-tion uses vibraSolu-tion sensors in the confines of the idler rolls and Honeywell uses sensors embedded inside the belt.

The addition of sensors and RFID tags to the standard idler rolls makes it necessary to have an energy source as well. This can be provided by for example a battery, such as in the concept version of the TEL department. The downside of this is that batteries need to be replaced after a while. Another option is integrating a dy-namo into the idler roll. There are already existing concepts of this, however, the optimal design is still in development. The current design solutions are experiencing difficulties in their assembly process so innova-tion of the designs is desired. As case example for this project, the current assembly problem experienced by Rulmeca is used as starting point for new designs.

The main goal of this project is to come up with three different design improvements to solve the currently experienced assembly problem. The designs have to consist of a standard idler roll, incorporated with a dynamo as energy harvester and should be designed in such way that assembly can be performed without experiencing the problem Rulmeca currently has. Preferably, the assembly process should be similar to those of the standard rolls.

Three designs have been proposed, each with its own advantage. In the first design only an extra part is in-cluded to help in the assembly process. The second design keeps the standard idler roll unchanged and adds an external part for generating energy. For the third design no extra parts are needed, only an alteration of one of the existing components. Design 1 and Design 2 can be useful in specific conditions where the customer has limitations to the ability to change the design of the original rolls. Design 3 seems most promising as new standard for intelligent idler roll design. It can be assembled using the same assembly method as a standard idler roll and it does not need extra bearings.

Summary (in Dutch)

Transportbanden worden wereldwijd gebruikt voor het transport van grote hoeveelheden bulk materiaal. Zoals met de meeste mechanische installaties moeten ook transportbanden onderhouden worden. Vaak worden deze installaties nog met de hand gecontroleerd door mensen die langs de transportband lopen. Door de grote schaal van vele van deze installaties is dit een zeer arbeidsintensief, duur, onbetrouwbaar en zelfs gevaarlijk proces. De belangrijkste reden voor onderhoudstaken zijn beschadigde rollen, waarbij het voornamelijk gaat om versleten lagers van deze rollen. Slecht of onvoldoende onderhoud van deze rollen kan catastrofale gevolgen hebben.

De industrie, en ook de Technische Universiteit Delft, werkt aan de ontwikkeling van geavanceerde moni-toring technologie van deze rollen. Uitgerust met monimoni-toring apparatuur zoals RFID tags en temperatuur sensoren worden deze standaard rollen ’Intelligente’ rollen, ook wel ’Smart rolls’ genoemd. De temperatuur sensoren meten een steiging in omgevingstemperatuur in de buurt van de lagers, wat een indicatie is van ver-sleten lagers. De combinatie van deze sensor en een actieve RFID tag (wat samen een node vormt) maakt het mogelijk om de hele transportband vanuit één centrale lokatie te monitoren. Informatie wordt gecommu-niceerd van node naar node doormiddel van een ZigBee draadloos netwerk. Er zijn al werkende voorbeelden van deze intelligente rol. Ook de Transport en Logistiek sectie van de TU Delft heeft een conceptversie van de rol met een batterij als energiebron. Een ander voorbeeld is het bedrijf Vayeron waar een ’Smart Roll’ is ontwikkeld die is uitgerust met meerdere sensoren. Naast de in-rol applicatie van sensoren zijn er ook voor-beelden waarbij de status van rol wordt gemonitord met behulp van andere methodes. Zo maakt bijvoorbeeld Intium Solutions gebruik van trilsensoren in de omgeving van de rollen en gebruikt Honeywell ’embedded sensors’ die in de transportband zitten.

Zoals zojuist al aangehaald, is door de toevoeging van sensoren en RFID tags ook een energiebron nodig. Dit kan bijvoorbeeld door behulp van een batterij, zoals in de conceptversie van de TEL sectie. Het nadeel hier-van is echter dat batterijen ook weer verhier-vangen moeten worden. Een andere mogelijkheid is het integreren van een dynamo in de rol. Er zijn hier al bestaande concepten van, echter deze kampen nog met problemen in het assemblageproces. Er is dus vraag naar innovatie van het huidige ontwerp. Als voobeeldcasus wordt het huidige assemblage probleem gebruikt dat wordt ondervonden door het bedrijf Rulmeca.

Het belangrijkste doel van dit project is om drie nieuwe ontwerpen te maken die het assemblage probleem van Rulmeca oplossen. De ontwerpen moeten bestaan uit een standaard rol met een dynamo ingebouwd als energievoorziening en moeten zo ontworpen worden dat de assemblage kan worden uitgevoerd zonder het huidige probleem dat wordt ondervonden door Rulmeca. Bij voorkeur is het assemblageproces gelijk aan dat van de standaard rollen.

Drie ontwerpen zijn voorgesteld, elk met zijn eigen voordelen. In het eerste ontwerp is alleen een extra on-derdeel toegevoegd om te helpen bij het assemblageproces. Het tweede ontwerp houdt de standaard rol ongewijzigd en voegt een extern deel toe voor het opwekken van de energie. Voor het derde ontwerp zijn geen extra onderdelen nodig, slechts een verandering van een van de bestaande onderdelen. Design 1 en De-sign 2 kunnen nuttig zijn in bepaalde omstandigheden waarbij de klant beperkingen heeft in de mogelijkheid om het ontwerp van de oorspronkelijke rollen te veranderen. Design 3 lijkt het meest veelbelovend als nieuwe standaard voor intelligente rollen. Het kan worden geassembleerd op eenzelfde wijze als een standaard rol en er zijn geen extra lagers nodig.

Contents

Summary v

Summary (in Dutch) vii

1 Introduction 1 2 Literature survey 3 2.1 Health monitoring . . . 3 2.2 Information management . . . 4 2.3 Case examples . . . 5 2.4 Current problems . . . 7 3 Problem definition 9 3.1 Current problem . . . 9 3.2 Design Criteria . . . 10 4 Design proposals 11 4.1 Solution Design 1: Centering spring. . . 11

4.2 Solution Design 2: External dynamo . . . 11

4.3 Solution Design 3: Integrated dynamo . . . 12

4.4 Comparison. . . 13

5 Conclusion 15

Appendix A: Design details 19

Appendix B: Solidworks files 21

1

Introduction

Belt conveyors are widely used to transport large volumes of bulk material. Compared to other modes of transport, like trucks and trains, belt conveyors are highly efficient and capable of high throughput, especially in areas where infrastructure is of low quality or not even existing. The length of today’s belt conveyors can reach up to tens of kilometers, with belt velocities up to 9 m/s. The highest capable belt conveyors carry out up to 40,000 tons lignite per hour [1].

Figure 1.1: Typical troughed belt conveyor (figure courtesy of Dunlop [2])

As with most mechanical installations, belt conveyors need to be maintained. Maintenance of these idler rolls is costly and labour intensive, mainly due to the large scale of many of these installations. Number of idler rolls can range from 2,000 in a 1,000 m conveyor to more than 20,000 in a 10,000 m conveyor. The most common reason for maintenance jobs are damaged idler roll, specifically bearing failure of an idler roll. Bad or insufficient maintenance can have catastrophic influences. It can lead to downtime of the belt conveyor (production loss, costing money) or even worse, belt fracture. In many applications, the belt conveyors are inspected manually by ’walking along the conveyor’. This is a labour intensive, slow, unreliable and even dan-gerous process. The belt conveyor can usually not be stopped for inspection, so doing this while its running has its risks [3].

The section of Transport Engineering and Logistics of Delft University of Technology (TEL) is developing an Intelligent Belt Conveyor Monitoring and Control (IBCMC) system [4]. By adding an detection system with acoustic, vibration and/or temperature related sensors and RFID chips into the idler roll, the state of the idler rolls can be monitored. Data transmission of the acquired information can be achieved by setting up a so-called a ZigBee wireless communication network. Each of the rolls is fitted with a sensor and RFID chip, together forming a node. Each node is capable measuring data and both sending and receiving this information. In this way, a network of roll-to-roll communication is formed that can result as reliable wireless connection.

2 1. Introduction

Figure 1.2: Standard idler roll (figure courtesy of Rulmeca [5])

The electric power that is needed for the sensor and active RFID tag is low enough that it can be drawn from a battery. However, this leads again to a maintenance intensive property, since all batteries need replacement. This can be solved by adding a energy harvesting technology to the roll. Since it is already rotating, mechani-cal generated energy seems to be the logimechani-cal choice. A first concept design has already been tested at the TEL lab of Delft University of Technology [6]. The roll manufacturer Rulmeca [5] has already tried to fabricate this type of roll. However, they are experiencing difficulties in their assembly process. Due to the change in de-sign, the assembly process had to be reconfigured. However, the problem is that even with their new method the assembly process is still not satisfying. In other words, the current design of the intelligent idler roll is not good enough and has to be improved.

Therefore, the main goal of this project is to come up with three different design improvements of the cur-rent intelligent idler roll design by Rulmeca. The designs have to consist of a standard idler roll, incorporated with a dynamo as energy harvester and should be designed in such way that assembly can be performed without experiencing the problem Rulmeca currently has. Preferably, the assembly process should be similar to those of the standard rolls.

First a literature survey will be done to get the know the product and the idea behind intelligent idler rolls. Also a look will be taken at competitive concepts of the intelligent idler rolls. The new designs of the idler roll will be made with use of the 3D modelling software Solidworks [7].

In this report first the results of a literature survey will be given in Chapter 1. In Chapter 2 the current problem will be explained and design criteria will be set. Next, three designs will be presented in Chapter 3 that integrate an energy harvester with an idler roll and solve the problem explained in the previous chapter. The focus of the design process is to solve the assembly problem that is currently experienced by Rulmeca. Lastly, a conclusion and possibilities for future research will be given in Chapter 4.

2

Literature survey

Inspection of idler rolls are currently often still carried out by driving/walking along the conveyor and man-ually see/hear if there are problems. Next to being very time consuming and dangerous, it is also not very reliably as a worker can easily miss a roll that is about to fail. In 2003 the first concept of automated main-tenance and intelligent monitoring of belt conveyors was introduced [8] and further extended in 2005 [9]. In 2007 the use of RFID was introduced to make a ’smart idler’. Since then several (research) institutions and companies have been working on this concept. Also Delft University of Technology and Rulmeca rolls (Italy) worked together on further development of the concept [10]. This chapter will take a closer look at the differ-ent technologies related to the monitoring of the idler rolls in belt conveyors described by researchers and/or used by companies.

Figure 2.1: Workers ’walking the line’ (figure courtesy of Martin Engineering) [11]

2.1. Health monitoring

Assessment of health of idler roll and data acquisition

First concern of an idler roll monitoring system would be "how to sense a roll is about to fail?". Different parameters can indicate that the roll or bearing is reaching the end of its life. Monitoring sensors can be categorised into mobile sensors and fixed sensors. Mobile sensors have the advantage that there is no need for complex network and infrastructure for the sensors, but there is no constant monitoring of all rolls at the same time and the time between two cycles of inspection may be too long. Fixed sensors can be installed on the roll support frame or inside the rolls [3].

4 2. Literature survey

Sensor types

Research has shown that there are several solutions. Since malfunction of roll bearings is the most common idler roll failure mode, most monitoring techniques focus on the bearings or consequences related to bearing failure [12]. Liu (2016) has performed laboratory and in-situ idler experiments to investigate whether different types of sensors can detect early stages of roll bearing failure. All sensors are intended to detect either one of the following three parameters: temperature, vibration or sound level.

The first indicator is temperature. Temperature can be measured with fixed (thermocouple) or mobile (infrared) sensoring techniques. Liu’s experiments show that damaged rolls show significant temperature increase during the tests [12]. It also shows that vibration sensors (accelerometers) can be used to detect damaged rolls at the final failure state. Liu was able to observe distinct differences comparing the RMS levels of intact and defect rolls. And lastly, Liu states that there is a positive and strong correlation between the tem-perate and the sound level of the rolls. However, all things considered the measurement of the temperature is suggested by Liu to be the most effective inspection method.

2.2. Information management

Communication

First of all, each idler roll need to be uniquely identifiable. Just knowing that ’some’ idler roll is nearly failing, isn’t much helpful. Next, every roll needs to be connected to a central monitoring system. And lastly, related parameters to the health of the idler roll need to be monitored constantly. Using wired connections is not really an option, as the number of idler rolls makes this very difficult. Also, this would not be a very reliable solution as depending on the environmental circumstances it is very prone to things like cable damage. This is where the use of Radio Frequency Identification (RFID) becomes very helpful. With the use of RFID, infor-mation can be transferred wireless between a sensor and the gateway. Identification becomes very easy as with RFID every sensor can be given an unique number. However, since the relatively small range of RFID tags, a solution is needed to reach the end of the belt conveyor where the central control system would nor-mally be located. By using node to node communication, a ZigBee wireless communication network can be formed [13].

RFID and nodes

As mentioned before, RFID is a very use full technique for belt monitoring applications due to several reasons: it is wireless, fast, uniquely identifiable, small and relatively cheap. When combining a sensor (for example, a thermocouple for temperature) with and RFID tag and some source of power, a node is formed [14].

Figure 2.2: Tag, circuit board with sensor and batteries forming a node (figure courtesy of Crossbow, Inc.[14])

When configured to form a so-called Hybrid Star (ZigBee) network, is it possible to communicate over large distances.

Network

The Hybrid Star configuration works as follows. Each roll is fitted with an RFID sensor node. Each node has the ability to communicate with surrounding nodes up to roughly 10 meter. By using roll-to-roll communi-cation it is possible to transfer information over large distances which can be over 10 km.

Each node can participate in data transmission and typically the idler pitch varies between 2.5-4.5 meters for carrying belt and 5-10 meters for the return strand. This means that even when one of the nodes fails, other nodes can continue the data transmission and thus ensuring a reliable connection [10])

2.3. Case examples 5

Figure 2.3: Roll-to-roll communication [10]

Figure 2.4: Example of a Hybrid Star (ZigBee) network [10]

2.3. Case examples

Usually, condition of the roll is monitored by looking at the condition of the bearings. But there are also ap-plications where support frame attachment is used. This section will provide some examples where idler roll monitoring techniques are being researched and/or in application.

TEL, Delft University of Technology

The TEL department from Delft University of Technology has been researching the application of an inte-grated thermal sensor connected to a battery for power and RFID tag for communication. They are also experimenting with the incorporation of an energy harvester inside the roll. Figure 2.5 shows the idler roll with battery-powered tag and sensor designed by the TEL department.

6 2. Literature survey

Vayeron

Vayeron is another company is working with a similar principle but have added additional vibrational sensor. According to a product trial evaluation document published by Vayeron themselves (Vayeron Pty Ltd, 2016) this sensor is placed inside the stator, which is mounted directly on the shaft of the roll. Furthermore, Vayeron states in this document that just monitoring the temperature and vibration levels will only help to detect stage 4 bearing failures, which is often to late to prevent costly brake down. They claim to employ acceleration enveloping spectral analysis in order to achieve early detection of stage 2 bearing defects. Vayeron also added a sensor to measure the actual roll RPM, which they then use as extra parameter in their detection algorithm [15]). Figure 2.6 shows the idler roll design by Vayeron.

Figure 2.6: Smart Idler roll from Vayeron (figure courtesy of Vayeron [16])

Intium Solutions

Intium Solutions work with a slightly different technique. Instead of incorporating a sensor inside a idler roll, they place a vibration sensor in the confines of the idler roll or integral with the frame structures on which the roll is supported [17]. A similar system for communication is used as explained in Section 2.2. A visualisation of the Roller Condition Monitoring System of Intium can be seen in Figure 2.7

2.4. Current problems 7

The advantage of this is that this system is less complex as sensors and energy harvesting systems do not have to be incorporated inside an idler roll. It can simply be attached to the current belt conveyor system and power can be provided with the use of solar panels. However, disadvantages are less reliability and less accuracy since signals can easily be interfered by neighbouring rolls or vibration of the support structure [3].

Honeywell

Another technology, patented by by Honeywell[19], is an in-belt plug sensoring system as shown in Figure 2.8. The encapsulated sensor system includes a pressure sensor, a vibration sensor, a temperature sensor and a controller. The system also has self-contained power supplies, for example batteries. When one of the sensors passes over an idler roll, it senses one or more characteristics of the condition of the idler roll. The plug is embedded in the underside of the belt after production, as temperatures during belt production are too high. Honeywell has a working prototype of the in-belt plug. Field tests have shown that the sensoring equipment was not damaged by the belt loading [18]. However, it is unclear to which extend the sensors already provide useful information and the technology seems still to be in developing phase.

Figure 2.8: Honeywell’s BeltAIS conveyor health monitoring system [20]

2.4. Current problems

Although there are already manufacturers using the concept of intelligent idler rolls commercially, it is defi-nitely still in developing stage. The following two aspects seem to be the biggest challenges in current devel-opment of the intelligent idler rolls:

• The temperature sensor seems the best option to use as sensor, however it still proves to be difficult to determine the right threshold values and parameters for early stage detection of failure (although Vayeron claims to have a working algorithm).

• Assembly process of an idler with integrated energy harvester is more complex than the standard roll, alternative designs are needed to simplify this process.

The design part of this research assignment focuses on the second point: improvement of the design in order to improve the assembly process. The next chapter will explain the current assembly problem experienced at

3

Problem definition

In this chapter the current assembly problem experienced by Rulmeca will be explained and the design cri-teria will be set.

3.1. Current problem

There is already a concept design of an idler roll with integrated energy harvester. However, the assembly of the idler roll is not yet optimal. Current assembly steps are shown . First step assembly steps of the standard roller will be explained in Figures 3.1(a)-(d), then the current assembly steps of the idler roller equipped with a dynamo will be explained with the use of Figures 3.3(a)-(d).

(a) step 1a (b) step 1b

(c) step 2a (d) step 2b

Figure 3.1: Standard idler assembly steps

In this standard assembly method two bearings are mounted, one on each side. After this step, the shaft is inserted through both bearings. When assembling a smart idler with electromagnetic energy harvester, the assembly method needs to be adapted. The shaft of this idler roll is fitted with an armature as seen in Figure 3.2b.

10 3. Problem definition

(a) Standard shaft (b) Shaft with armature

Figure 3.2: New shaft design

This means that the shaft cannot be inserted at the last assembly step. The new steps are shown in Figures 3.3(a)-(d).

(a) step 1 (b) step 2

(c) step 3 (d) step 4

Figure 3.3: Intelligent idler assembly steps

So compared to the original assembly method, in the new method at first only one bearing is mounted, then the shaft is inserted, after which the second bearing is mounted from the other side. This brings us to the current problem. With this last assembly method is proven difficult to stabilise the shaft after it has been inserted into the first bearing, thus making the mounting of the second bearing afterwards hard to perform efficiently.

3.2. Design Criteria

The task is to design an idler roll with integrated energy harvester and sensoring system. The following criteria need to be kept in mind:

• The energy harvester (dynamo) will consist of a stator which is connected to the idler shaft and the rotor which is connected to the roll tube

• The energy source needs to be capable to deliver enough power

• Rigid design, able to withstand heavy environmental circumstances (heat, moist, vibrations)

• Assembly requirements: design should solve the current assembly problem of Rulmeca as explained in Section 3.1

4

Design proposals

This chapter will discuss three possible idler roll designs with a dynamo as energy harvester to power the active RFID tag and sensors. These designs should at least solve the assembly problem experienced at Rul-meca, as explained in Section 3.1. More detailed figures can be found in Appendix A. The Solidworks files are admitted with the report digitally (see also Appendix B).

4.1. Solution Design 1: Centering spring

The first solution is as an attempt to solve the problem as simple as possible. By only adding one extra shaft stabilising part. The part has flexible ends in order to center itself inside the idler tube.

(a) Full assembly (b) New shaft design with centering spring

Figure 4.1: Solution Design 1

The pro’s and con’s of this design solution can be found in Table 4.1.

Table 4.1: Pro’s and con’s of Design 1

Pro’s Con’s

Simple solution since it doesn’t change the current design. It only adds an extra part.

Centering of the shaft might be insufficient

Extra bearings needed: adds another resistance and maintenance factor

4.2. Solution Design 2: External dynamo

In the second design, the attempt was to fully externalise the energy harvester. The dynamo moved to the other side of the support. Difficulty here is the transmission of the mechanical energy from roll to dynamo, which is solved by adding gears. The dynamo in this design is smaller compared to the previous design.

12 4. Design proposals

However, this is not expected to be a problem, since a concept version of the bigger sized dynamo turned out to generate way too much power [6].

(a) Full assembly (b) External assembly for dynamo

Figure 4.2: Solution Design 2

The pro’s and con’s of this design solution can be found in Table 4.2.

Table 4.2: Pro’s and con’s of Design 2

Pro’s Con’s

Fully external, so original roll can be re-used.

Gearing system: extra costs and extra maintenance.

Cost-saving for existing systems since roll doesn’t need replacement.

Although parts of original roll can be re-used, probably a new (longer) shaft is needed. This means the roll still needs to be fully re-assembled.

Extra bearings needed: adds another resistance and maintenance factor.

4.3. Solution Design 3: Integrated dynamo

The final design comprises an internal dynamo inside the roll, but placed outside of the bearings. The shaft can be inserted after both sides are closed with bearings. This means the same assembly method can be used as for the standard rolls. Similar to the second design, also in this third design the dynamo is made smaller.

(a) New idler roll design (b) Exploded view

4.4. Comparison 13

Figure 4.4: Sectionview Design 3

The pro’s and con’s of this design solution can be found in Table 4.3.

Table 4.3: Pro’s and con’s of Design 2

Pro’s Con’s

Original assembly method can be used

Change of location of one of the two bearings might have a negative impact on the distribution of forces.

No extra parts needed, just a redesign of the the bearing mount

Easy replacement of dynamo, since it is not fixed to the outer shell of roll No extra bearings needed.

4.4. Comparison

Although all three designs aim on a better assembly process, each of the three design solutions has its own advantages. The solutions can be categorised as follows:

• Design 1: Simple. By adding only one extra part to hold the shaft in place. Current design of smart idler roll is kept unchanged. This method can be preferred if for example the ’closing’ ends of the rolls (in which the bearings are mounted) are designed in a different manner, making it harder to change its design. The addition of an extra part to stabilise the shaft can preserve the original ’closing’ ends. • Design 2: External. By moving the energy harvesting system completely outside of the roll, the original

idler rolls can be kept in place. This solution can be preferred if for some reason the original rolls need to be preserved (f.e. if they are really expensive). Although reassembly of the idler roll is probably needed since the shaft needs to be longer, the same rolls can be re-used.

• Design 3: Integrated. Complete new integrated design of the energy harvester. When starting from scratch, this design is probably the best choice since no extra parts are needed. Only an alteration of the standard closing ends/bearing holders.

All-in-all the third design seems most promising since the reasons to choose for Design 1 or 2 are only specific cases. Furthermore, only the third design complies to both the main goal of the design and the preferable

5

Conclusion

Much research has been done on improvement of the processes and equipment used for bulk handling. One of these topics is the development of better monitoring abilities of the idler rolls in bulk belt conveyors. The maintenance of these rolls is currently very labour intensive and dangerous work. Rolls with integrated sen-sors to measure the state of the bearings and RFID tags for communication can help to improve the main-tenance efficiency. Rulmeca is a company who has already tried manufacturing a version of the ’intelligent’ idler roll, but experienced problems during assembly.

To recap the main goal as defined in Chapter 1: The main goal of this project is to come up with three

dif-ferent design improvements of the current intelligent idler roll design by Rulmeca. The designs have to consist of a standard idler roll, incorporated with a dynamo as energy harvester and should be designed in such way that assembly can be performed without experiencing the problem Rulmeca currently has. Preferably, the assembly process should be similar to those of the standard rolls.

Three designs have been proposed, each with its own advantage. Design 1 and Design 2 can be useful in specific conditions where the customer has limitations to the ability to change the design. Design 3 seems most promising as standard for intelligent idler roll design. It can be assembled using the same assembly method as a standard idler roll (at Rulmeca) and it does not need extra bearings in contrast to the other two designs.

Further research can be done by improving the design in more detail. The required size of the dynamo can be looked at, as this determines the final design. The design can be extended by including the (temperature) sensor in the design and assembly method. The impact of placement of the bearings on the distribution of forces can be investigated using FEM analysis.

Appendix A: Design details

This appendix contains additional figures of the three designs. They can be found on the following three pages.

Design 1

Figure 1: Design 1: side-view

18 5. Conclusion

Design 2

Figure 3: Design 2: side-view

19

Design 3

Appendix B: Solidworks files

The designs made in Solidworks are submitted digitally together with this report. The files include the original roller design and the three new designs as shown in Chapter 4.

Bibliography

[1] Y.Pang and G.Lodewijks. The application of RFID technology in large-scale dry bulk material transport system monitoring. 2011 IEEE Workshop on Environmental Energy and Structural Monitoring Systems (EESMS), pages 5–9, 2011.

[2] Dunlop. Dunlop conveyor belting. http://www.dunlopconveyorbelting.com/. [Online; 02-11-2016].

[3] G. Lodewijks X. Liu and Y. Pang. Intelligent maintenance of large-scale belt conveyor idler rolls: State-of-the-art and opportunities. International Journal of Production Research, 2007.

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