Design of Equipment to Recycle Marsclay

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Design of Equipment to Recycle Marsclay

Diplomová práce

Studijní program: N2301 – Mechanical Engineering

Studijní obor: 2302T010 – Machines and Equipment Design Autor práce: Jeba Christo Christober Thangaraj

Vedoucí práce: Ing. Petr Zelený, Ph.D.

Liberec 2018

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Design of Equipment to Recycle Marsclay

Master thesis

Study programme: N2301 – Mechanical Engineering

Study branch: 2302T010 – Machines and Equipment Design Author: Jeba Christo Christober Thangaraj Supervisor: Ing. Petr Zelený, Ph.D.

Liberec 2018

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Byl jsem seznámen s tím, že na mou diplomovou práci se plně vzta- huje zákon č. 121/2000 Sb., o právu autorském, zejména § 60 – školní dílo.

Beru na vědomí, že Technická univerzita v Liberci (TUL) nezasahuje do mých autorských práv užitím mé diplomové práce pro vnitřní potřebu TUL.

Užiji-li diplomovou práci nebo poskytnu-li licenci k jejímu využití, jsem si vědom povinnosti informovat o této skutečnosti TUL; v tom- to případě má TUL právo ode mne požadovat úhradu nákladů, které vynaložila na vytvoření díla, až do jejich skutečné výše.

Diplomovou práci jsem vypracoval samostatně s použitím uvedené literatury a na základě konzultací s vedoucím mé diplomové práce a konzultantem.

Současně čestně prohlašuji, že tištěná verze práce se shoduje s elek- tronickou verzí, vloženou do IS STAG.

Datum:

Podpis:

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Declaration

I hereby certify that I have been informed the Act 121/2000, the Copyright Act of the Czech Republic, namely § 60 - Schoolwork, applies to my master thesis in full scope.

I acknowledge that the Technical University of Liberec (TUL) does not infringe my copyrights by using my master thesis for TUL's internal purposes.

I am aware of my obligation to inform TUL on having used or licensed to use my master thesis; in such a case TUL may require compensation of costs spent on creating the work at up to their actual amount.

I have written my master thesis myself using literature listed therein and consulting it with my thesis supervisor and my tutor.

Concurrently I confirm that the printed version of my master thesis is coincident with an electronic version, inserted into the IS STAG.

Date :

Signature :

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ACKNOWLEDGEMENT

First and foremost, I would like to thank the GOD ALMIGHTY for showering his blessings throughout my life.

I take this chance to express my deep sense of gratitude to the Univeristy, TECHNICAL UNIVERSITY OF LIBERECfor providing an excellent infrastructure and support to pursue project work.

My special thanks also have to go to Ing. PETR ZELENÝ Ph.D. who, in spite of having practically no spare time, still managed to find some time to provide me help and valuable advices during the whole journey of my thesis.

It is with immense gratitude that I acknowledge the support of the company SVOTT s.r.o. providing me this great opportunity to develop in deepest manner my engineering skills while accomplishing this diploma thesis and help them to further develop the importance in machine construction design.

I am indebted to thank especially Ing. JÁN SVRČEK for his professional guidance, encouragement and good advices all along. This thesis is a much work better thanks to his supervision.

I would be sinner if I fail to thank our beloved parents who sweated their blood to make me study this course.

I am very much grateful to all the staff members and my friends who helped a lot to collect the informations about this project.

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TÉMA: KONSTRUKCE ZAŘÍZENÍ PRO RECYKLACI MODELÁŘSKÉ HLÍNY MARSCLAY

ABSTRAKT:

Cílem této práce je navrhnout zařízení pro recyklaci použité modelářské hlíny značky Marsclay, která je používána pro výrobu designových prototypů aut v měřítku 1:1 firmou SVOTT s.r.o. Výstupem z tohoto zařízení budou lisované válce z modelářské hlíny. Byla diskutována možnost recyklace různých typů modelářské hlíny. Zařízení je navrženo pomocí softwaru CATIA a je provedena nezbytná analýza dle požadavků zadavatele. Pro recyklaci modelářské hlíny Marsclay je použit nový princip. Výrobní kapacita tohoto stroje je vyšší než u strojů pro standardní recyklaci hlíny, které jsou k dispozici na trhu. Případným zavedením tohoto stroje ve firmě by došlo ke snížení nákladů na recyklaci hlíny, protože tento stroj je levnější ve srovnání s jinými stroji. Navrhované řešení dle požadovaných parametrů a rozměrů stroje bylo předloženo zadavateli.

KLÍČOVÁ SLOVA:

Recyklace, modelářská hlína, recyklační stroj, návrh, analýza, konstrukce

THEME: DESIGN OF EQUIPMENT TO RECYCLE MARSCLAY

ABSTRACT:

The aim of this thesis is to design an equipment to recycle the used model clay which is been used in the field of model prototypes of cars in the scale of 1:1 by SVOTT s.r.o. The output from this equipment will be in the form of molded cylinders of Marsclay. Moreover, the existing possibilities of recycling several types of clay has been discussed. A new design of this device is designed on CATIA software and performed for necessary analysis according to the requirements. A new principle is applied to recycle the Marsclay. The batch capacity of this machine is higher than the machines for the normal clay recycling which is available on the markets. By implementing this machine in the company, time consumption for the recycling of clay is reduced and this machine is cheaper when compared with other machines.

The design solution according to the required parameters and dimensions of the machine are submitted to the consultant company.

KEYWORDS:

Recycle, Model Clay, Recycling Machine, Design, Analysis

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LIST OF FIGURES

Fig. 3.1: A clay model of BMW 1 series ... 21

Fig. 3.2: Standard cylinder of Marsclay from Staedtler ... 23

Fig. 3.3: Clay modelers working on 1:1 model car... 23

Fig. 3.4: Marsclay Medium - Hardness vs. Temperature ... 25

Fig. 3.5: Marsclay Medium - Hardness vs. Time ... 26

Fig. 4.1: Horizontal and Vertical Pugmill ... 27

Fig. 4.2: C.W. Kilborn Pugmill and Stone Separator ... 28

Fig. 4.3: E.M. Skipper pugmill ... 29

Fig. 4.4: Auger design of E.M. Skipper Pugmill ... 30

Fig. 4.5: Shimpo NVS-07 Pugmill ... 31

Fig. 4.6: Peter Pugger PM-50 ... 32

Fig. 5.1: Double chamber with hydraulic or pneumatic piston... 34

Fig. 5.2: Double chamber with two different augers ... 36

Fig. 5.3: Single chamber with oil as heating medium... 37

Fig. 5.4: Single chamber with water as heating medium ... 38

Fig. 6.1: Clay Chips ... 40

Fig. 6.2: HFM arrangement in TUL Laboratory ... 41

Fig. 6.3: Principle of HFM ... 41

Fig. 6.4: Clay specimen for testing ... 42

Fig. 6.5: Thermal conductivity test on Marsclay ... 42

Fig. 6.6: Schematic cross-sectional view of recycling equipment ... 44

Fig. 7.1: 3D Isometric View of Marsclay Recycling Machine ... 52

Fig. 7.2: Clay Chamber Assembly with Hopper ... 53

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Fig. 7.4: Outer Chamber ... 55

Fig. 7.5: Heating Coil... 55

Fig. 7.6: Clay Chamber Connector ... 56

Fig. 7.7: Hopper with Hopper Lid ... 57

Fig. 7.8: Chamber Support ... 57

Fig. 7.9: Ball Valve ... 58

Fig. 7.10: Hinges ... 59

Fig. 7.11: Lock Rod ... 59

Fig. 7.12: Parts of Screw Conveyor System ... 60

Fig. 7.13: Auger Assembly ... 60

Fig. 7.14: Auger Shaft ... 61

Fig. 7.15: Flight with Constant Diameter ... 62

Fig. 7.16: Flight with Variable Diameter ... 62

Fig. 7.17: Clay Chamber End Plate ... 63

Fig. 7.18: Frame with Control Panel ... 64

Fig. 7.19: Specifications of Coupling ... 65

Fig. 7.20: Specifications of Bearing Lock Nut ... 65

Fig. 7.21: Specifications of Bearing Lock Washers ... 66

Fig. 7.22: Clay Roller Shelf ... 67

Fig. 7.23: Cross-section View of Marsclay Recycling Machine ... 68

Fig. 8.1: FBD of Marsclay Recycling Machine ... 70

Fig. 8.2: Displacement of Auger Assembly ... 71

Fig. 8.3: Von Mises Stress Result for Auger Assembly ... 71

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LIST OF TABLES

Table 4.1: Specification of Shimpo NVS-07 Pugmill ... 31

Table 4.2: Specifications of Peter Pugger PM-50 ... 32

Table 5.1: Analysis on Proposals ... 39

Table 6.1: Results of HFM... 43

Table 6.2: Basic dimensions of clay chamber 1 ... 44

Table 6.3: Material properties and input condition ... 45

Table 6.4: Volumetric Calculations of Clay ... 45

Table 6.5: Volumetric Calculations of Water ... 46

Table 6.6: Temperature distribution across the chamber ... 47

Table 6.7: Time required for heating the clay... 49

Table 6.8: Time required for heating the water ... 50

Table 8.1: Material & Manufacturing Cost for Machine ... 73

Table 8.2: Cost of Standard Products ... 73

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LIST OF ABBREVIATIONS

ACMI - Art and Creative Materials Institute AISI - American Iron and Steel Institute

Al. - Aluminium

AST - Advanced Spiral Technology

ASTM - American Society for Testing Materials CAD - Computer Aided Design

CB - Cantilever Beam

CC - Clay Chamber

CI - Cast Iron CZK - Czech Koruna

DB - Data Book

FBD - Free Body Diagram

GSA - Generative Structural Analysis HFM - Heat Flow Meter

HMT - Heat and Mass Transfer HTC - Heat Transfer Coefficient LLC - Limited Liability Company OB - Overhanging Beam

PL - Point Load SS - Stainless Steel

TUL - Technical University of Liberec UDL - Uniformly Distributed Load USA - United States of America UVL - Uniformly Varying Load

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LIST OF SYMBOLS

ΔT Change in temperature (K) λ Coefficient of trough loading ρc Density of clay (kg/m³) ρw Density of water (kg/m³) Cpc Specific heat of clay (J/kgK) Cpw Specific heat of water (J/kgK) C0 Material resistance coefficient ds Diameter of the screw (m) DN Diameter of the nozzle (m) hb HTC of air (W/m²K) hw HTC of water (W/m²K)

ka Thermal conductivity of clay (W/mK)

k1 Thermal conductivity of Al Alloy 2024-T6 (W/mK) k3 Thermal conductivity of SS AISI 304 (W/mK)

k4 Thermal conductivity of rockwool insulation (W/mK) K Coefficient of conveyor housing inclination

l Length extruded in one rotation of conveyor (m/rot) L Installed length of screw conveyor (m)

L1 Length of clay chamber 1 (mm)

m Mass (kg)

mc Mass of clay (kg) mw Mass of water (l)

n Speed of screw conveyor (rpm) p Pitch of screw conveyor (m)

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P Minimum power required for the motor (kW)

PH Power required to transport the material horizontally (kW) PN Power required to operate unloaded screw (kW)

q Heat energy (J)

qc Heat energy required to raise the temperature of clay (J) qw Heat energy required to raise the temperature of water(J) Qc Transported capacity (tonnes/hr)

r Radius of nozzle mouth (m)

r

a Radius of auger shaft (mm)

r

1 Inner radius of clay chamber IN (mm)

r

2 Outer radius of clay chamber IN (mm)

r

3 Inner radius of clay chamber OUT (mm)

r

4 Outer radius of clay chamber OUT (mm)

r

5 Outer radius of Insulation (mm) R Thermal resistance (K/W)

Rb Thermal resistance at SS outer due to convection (K/W) Rw Thermal resistance at Al. Alloy outer due to convection (K/W) R1 Thermal resistance at Al. Alloy due to conduction (K/W) R2 Thermal resistance at SS inner due to convection (K/W) R3 Thermal resistance at SS due to conduction (K/W)

R4 Thermal resistance at insulation material due to conduction (K/W) s Conveyor Nozzle area (m²)

t Time (min)

tc Time required to heat the clay (min)

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tw Time required to heat the water (min) T Required Torque (Nm)

Ta Temperature at shaft outer (K) Tb Temperature of ambient air (K)

T1 Temperature at inner radius of CC IN (K) T2 Temperature at outer radius of CC IN (K) T3 Temperature at inner radius of CC OUT (K) T4 Temperature at outer radius of CC OUT (K) T5 Temperature at outer radius of CC insulation (K)

Q Heat flow (W)

v Linear velocity (m/min) V Volume (m³)

Vu Useful volume (m³)

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1. INTRODUCTION

Engineering is mathematical and scientific fundamentals implemented in designing, manufacturing, operating and maintaining. In these, the reverse of manufacturing is recycling.

In other words, recycling is the process of consuming the products as input and delivering materials as output. Now-a-days, it is well established and highly developed. The manufacturing triangle of function, cost and quality can also be used to interpret recycling issues with products. Certain products can be easily recycled into separate high-quality materials, whereas others cannot (only at high costs). In certain products, heterogeneous products can be recycled for two homogeneous base materials. And for an easy case, homogeneous products are recycled for its base material.

Recycling is primarily an economic activity which is done for profit. If the value of the recovered materials exceeds the costs of recovery, then recycling makes economic sense.

Basically, recycling consists of four steps:

i. Collection of products to be recycled

ii. Liberation of products from foreign materials

iii. Manipulation of products (shredding, moving, melting, etc.) iv. Reprocessing of products (die casting, forging, extruding, etc.)

Recycling processes require energy to operate. However, compared to making materials from the primary sources, recycling consumes significantly less energy. The fundamental reason behind this difference is that recycling only involves mechanical and physical manipulation such as shredding, moving, melting. But the typical primary production includes chemical manipulation also, like synthesis of polymers, smelting of metal ores which starts from the basic structure of materials.

For a better understanding, let us take the recycling of car. Cars containing hundreds of materials and thousands of components can be recycled as efficient as they are, with up to 85% of all the materials being recycled. The main metals are recovered such as Aluminium up to 80%, Copper up to 89%, Iron and Steel even up to 98%. However, plastic recovery is poor at only 2%.^[1]

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2. AIM OF THESIS

This thesis deals with the recycling methodology and constructing a new equipment to recycle the used model clay for the company namely SVOTT s.r.o, which is situated in Mladá Boleslav, Czech Republic. Modelling clay is used in the design of automobile body for a better aesthetic view and good aerodynamic effect. This clay is then breaking up for small pieces with the help of machines. In order to reduce the cost of new clay purchased for the next car, if the used model clay is recycled, it is an economic one. The typical clay used for this process is Marsclay medium. In this thesis, a recycling equipment to recycle the Marsclay is designed with the capacity of 100 kg per hour. Through this machine, the model clay can be recycled several times and the company earns a lot of profit. The basic principle behind the recycling of model clay is heat transfer through the conduction and convection processes. Heat from the hot water is transferred to the clay for its butter-soft form and it is recycled. The input material for this machine is tiny pieces of dry model clay and the output is molded cylinders of butter- soft clay with 60 mm diameter. Calculations of thermal, volumetric, mechanical are the primary things in order to proceed for the design of the equipment. CATIA V5 is used for the designing and drafting purpose.

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3. MARSCLAY AND SVOTT 3.1. WHAT IS CLAY?

Clay is considered as one of the oldest materials which is used as building materials on Earth. It is a fine grained natural rock or soil material that combines one or more clay minerals with the traces of metal oxides and organic matter^[2]. In this, modelling clay is used for building and sculpting. Modelling clay is broadly classified as follows according to their material compositions, production processes and its usage.

a. Ceramic clay b. Oil-based clay c. Polymer clay d. Paper clay

e. Play doh (Salt dough)

f. Industrial plasticine (Industrial clay)

3.2. CLAY IN AUTOMOBILE INDUSTRY

Fig. 3.1: A clay model of BMW 1 series^[2]

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Launching a new car model consumes long period such as few years. Even today, computer models such as CAD data are not sufficient to evaluate a car design. In order to creating the proper design, based on Aerodynamics as well as aesthetic point of view, some models are built using model clay (Industrial plasticine) in the ratio 1:4 and then with the real visual ratio of 1:1. This is built over a wooden or iron frame which is covered with styrofoam usually. Clay is applied and sculptured over the foam. Clay experts then use various tools to finalize the shape of the car. Fig.3.1 shows the semi-finished model clay car of BMW 1 series over a static frame structure.

3.3. ABOUT SVOTT

Construction of clay modelling of a car will be usually done in a studio (Company).

One of the company which is doing these types of jobs for automobile companies is SVOTT s.r.o. SVOTT consists of a team of specialists, providing the services in developing the design of cars. It was founded in 2007 and since it is serving for world’s leading automotive industries.

It is situated in Mladá Boleslav, the place where the ŠKODA was born.

In SVOTT s.r.o., at first the clay is heated upto 60˚C in an oven. For every 4-6 hours, the bars are completely reheated. The clay can be heated several times. After warming up, the clay is butter softened and layered onto a dry and dust free substructure. Air traps should be avoided during the process. When this is done, the car almost has the desired shape. After cooling, the detailed shaping takes place with experts (by hands or milling machine). Finally, the surface will be polished. Direct sun light exposure should be avoided as well as heating of clay more than 70˚C also be avoided. After the detailed carving, the clay model can also be painted. Now it will look like a real car.

After completing the model of the car, the model is converted into 3D CAD data through 3D scanning method with the help of robots. When the car model is successfully accepted by the automotive industries, the clay used in the model car will be broken into small pieces and chips. But, these pieces are hard and it temporarily loses its sculpturing characteristics. Due to this characteristic change, it is not possible to sculpt the clay in the present condition. If the clay can be used again and again for the same purpose, then the investment cost for the clay can be minimized. So, recycling of clay is needed for SVOTT.

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3.4. MARSCLAY

Industrial plasticines are supplied worldwide by 2 main producers. They are i. Staedtler from Germany, which is also known for FIMO.

ii. Chavant, which was founded by the French Chemist Claude Chavant and is now located in New Jersey, USA^[2].

SVOTT s.r.o. is using Marsclay Medium 8432M / 8432MC. This is a special plasticine.

The supplier of the Industrial Plasticine is Staedtler from Germany.

Fig. 3.2: Standard cylinder of Marsclay from Staedtler^[3]

The cost of Marsclay Medium starts from 270 CZK per kg. It is usually in the shape of cylinders with the diameter of 60 mm as shown in fig.3.2.

Fig. 3.3: Clay modelers working on 1:1 model car^[4]

This clay is customized by the clay modelers to the specific need of the clients from the Automotive Industry. By hand or with a milling machine the designs for the future car models

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are produced at different scales. At room temperature between 15˚C - 25˚C, the clay remains the characteristic to keep its shape and also be workable with tools. Its surface does not harden;

therefore, it is very sensitive to sharp edges. For example, impressions with a fingernail are possible. This styling clay is dimensionally stable. So that, very fine details can be modeled.

It will stick very well with the usual substrates such as wood, hard foam and metal. It is also tear-resistant, aging resistant and odorless.

3.4.1. TECHNICAL INFORMATION ABOUT MARSCLAY^[5]

✓ Composition : Wax, Oil, Fillers, Pigments

✓ Density : 1.45 g/cm³, De-aired

✓ Color : Oxid Brown

✓ Odor : Neutral

✓ Linear Shrinkage Coefficient : 2.8 x 10^-4 K^-1 (cooling from 60˚C to 22˚C) 0.8 x 10^-4 K^-1 (cooling from 22˚C to -12˚C)

✓ Shelf Life : min. 24 months at Temperatures from 0˚C to 30˚C

✓ Working Temperature : 55˚C to 60˚C

✓ Degree of Hardness : Medium

✓ Shore Hardness A : 62 (at 20˚C)

✓ Penetration (Hardness) : 20˚C 40˚C 60˚C

(according to ASTM D937-92) 22 50 122 (1/10mm)

✓ Solubility : insoluble in water,

partially soluble in organic solvents

✓ Toxicology : toxicologically harmless, certified by ACMI, USA

3.4.2. INSTRUCTIONS TO USE MARSCLAY^[5]

✓ As a permanently malleable compound Marsclay medium remains pliable and can be used again and again. ie. Recyclable.

✓ When heated to 55˚C to 60˚C, the clay becomes soft and pliable.

✓ The heating period is about 5 hours (depending on type and loading of oven).

✓ At Room Temperature, up to 25˚C, the models keep their contours and edges.

✓ Modifications can be made to the finished model simply and dust free.

✓ Wood, Polystyrene and hard foams can be used as base materials.

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✓ Base materials and the warm modelling clay bond without the need of adhesives.

✓ Once the top surface has cooled down, the model can be shaped by hand or milling machines.

✓ Due to the special bonding qualities of the clay, only small amounts of material need to be applied in order to repair damaged sharp edges.

✓ By applying of bigger masses, we commend to warm up the base layer for an optimum bond.

✓ Grave quantities should be applied in layers.

✓ Finishes with modelling film can be removed quickly and easily.

✓ When using a heat-gun do not exceed temperature over 60˚C.

✓ The clay-model can be casted with gypsum or silicone. As releasing agent shellac can be used.

✓ By hot conditions or direct solar radiation softening of the surface occurs.

✓ The clay can be lacquered with Clay Peel.

✓ Soiled Surfaces can be cleaned with cleaner solvent.

3.4.3. COOLING RATE OF MARSCLAY

Fig. 3.4: Marsclay Medium - Hardness vs. Temperature^[5]

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Fig. 3.5: Marsclay Medium - Hardness vs. Time^[5]

From the fig.3.4 and fig.3.5, it is clearly stated as when the temperature decreases as the time increases, the hardness increases.

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4. LITERATURE REVIEW 4.1. WHAT IS PUGMILL?

Pugmill is the machine used to mix clay or other materials into a plastic state ie. to recycle the used clay. It is a fast-continuous mixer. Usually the output of the pugmills are in cylinder shape with respect to the diameter of nozzle. Pugmills can be constructed horizontally as well as vertically according to the orientation needed. A horizontal pugmill and vertical pugmill are shown in fig.4.1. Additionally, pugmills can be classified as deairing pugmills as non-deairing pugmills on the basis of operating condition.

Fig. 4.1: Horizontal and Vertical Pugmill^[6]

The pugmills heretofore employed for mixing ceramic materials have been of two general types.

a. In the first type, the mill has a single chamber for both mixing and extruding the material.

b. In the second type, the mixing and extrusion are performed in separate chambers and this type being the one most generally used in the industries.

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However, in both cases the mixing and extruding augers have either been mounted on the same shaft or driven through gearing at fixed relative speeds.

4.2. PUGMILLS FROM THE HISTORY

In the early 19^th century, pugmills were constructed and horses were used to drive it.

As the years gone by, pugmill undergone various technological development and resulted in a comfort output. Pugmills were powered up by electricity and the quantity of output is considerably increased. Among those pugmills, two different and important pugmills are taken into this study.

i. C.W. Kilborn pugmill ii. E.M. Skipper pugmill

4.2.1. C.W. KILBORN PUGMILL

Fig. 4.2: C.W. Kilborn Pugmill and Stone Separator^[7]

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In the year of 1910, an American inventor namely Chauncey W. Kilborn invented a pugmill to mix the clay with water to form a homogeneous matter of clay. This invention further contemplates a stone separator which will operate in an effective manner to work the clay and remove all stones and hard substances. In his model, he used a tapered auger to mix and extrude the clay. Both mixing and extruding takes place inside a single chamber^[7]. This auger looks like a screw conveyor as shown in fig.4.2.

4.2.2. E.M. SKIPPER PUGMILL

Fig. 4.3: E.M. Skipper pugmill^[8]

In the year of 1947, again an American Edward M. Skipper from the General Electric Company, New York came up with a new idea of pugmill. This type of pugmills were widely used by the insulator industries. The primary objective of this invention is to provide and improved apparatus for producing homogeneous stress free ceramic mixtures from the starting materials of a wide range of consistencies. This state was obtained by the help of vacuum chamber. At the meantime, it controlled the moisture and air content of clay. Hence it serves as both soft and hard pug. This pugmill has two separate chambers for mixing and extrusion of clay.^[8] A specially designed auger is used in this pugmill and is shown in fig.4.4.

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Fig. 4.4: Auger design of E.M. Skipper Pugmill^[8]

4.3. COMMERCIAL PUGMILLS

Combination of older inventions with the high-end technology brought a large number of pugmills available in the market. For a better understanding about commercial pugmills, two different pugmills were chosen on this study.

i. Shimpo’s Deairing Pugmill (NVS-07 Pugmill)^[9]

ii. Peter Non Deairing Pugger (PM-50)^[10]

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4.3.1. SHIMPO PUGMILL

The NVS-07 type Shimpo’s pugmill is a deairing pugmill mixer features a powerful 1 HP motor for mixing and extruding. It is made up of stainless steel. The clay cutter and roller shelf are included and having an easy access for cleaning and maintenance. This machine costs about 125,000 CZK. The batch capacity of this type machine about 25 kg/batch.^[9]

Fig. 4.5: Shimpo NVS-07 Pugmill^[9]

The specification of the Shimpo NVS-07 pugmill is given below:

MODEL NVS - 07

MOTOR Powerful 1 HP with Gear Drive Motor

POWER SOURCE 115V/60Hz

DUAL SAFETY SYSTEM Featuring Limit Switch and Overload Protection MAX BATCH CAPACITY 55 lbs. ≈ 25 kg

EXTRUDING CAPACITY 730 lbs/hour HOPPER 8.5" x 11.5"

STRUCTURE Stainless Steel

VACUUM PUMP SYSTEM Vacuum Pump (Oil-Free) NOZZLE DIAMETER 3.5" Nozzle

WEIGHT 310 lbs.

WARRANTY 5 years

Table 4.1: Specification of Shimpo NVS-07 Pugmill^[9]

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4.3.2. PETER PUGGER

The PM-50 type Peter pugger is a non-deairing pugmill mixer features a powerful 2 HP motor for mixing and extruding. Shaft and auger are made up of stainless steel. When the nozzle is removed, the cleaning will be easy. This machine costs about 116,000 CZK. The batch capacity of this type machine about 61 kg/batch.^[10]

Fig. 4.6: Peter Pugger PM-50^[10]

The specification of the Peter pugger PM-50 pugmill is given below:

MIXER-PUGGER PM-50

Maximum Batch Capacity 135 lbs. ≈ 61 kg Hopper Door Size 8" x 11"

Mixing Rate 300 lbs. per hour

Pugging Rate 1200 lbs. per hour

Pug size 3" diameter

Dimensions 30"H x 20"W x 46"L

Crated Weight 400 lbs. (Ships LTL Trucking)

Vacuum Pump N/A

Electrical 2HP, 1ph, 12amps at 240V

Table 4.2: Specifications of Peter Pugger PM-50^[10]

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4.4. CONCLUSION FROM THE LITERATURE REVIEW

With respect to the construction, horizontal pugmills are preferable, because, for vertical pugmills, the base should be made very strong it needs large amount of metal which results in a heavy weighed machine. It requires very small area, for a high output it seems on a vigorous height.

The usual market machines are very high in cost as well as not meets the required output. So, it is decided to design a better machine with high output in a cheaper cost. In order to attain the new better machine, the following ideas are projected.

✓ Increase the size of the hopper.

✓ Heat the dry clay up to suitable temperature with the help of heating coils or with oil/water inside casing.

✓ Conventional auger will be replaced by specially designed auger or with combination of two augers.

✓ Improving the design of nozzle.

✓ Changing the basic principle of recycling.

✓ By splitting the mixing chamber with mixing blades and extruding chamber with hydraulic or pneumatic pistons.

✓ Making the output cylinders in a standard length by cutting it automatically by cam mechanism or others.

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5. PROPOSED METHODS

5.1. INTRODUCTION TO PROPOSED METHODS

Based on the literature review, so many ideas came onto mind which are possible to improve the mechanism as well as output efficiency according to the required parameters.

Among those, four methods are proposed to analyze for its strength and its weaknesses in order to select the optimal solution. The proposed methods are as follows:

i. Double chamber with hydraulic or pneumatic piston ii. Double chamber with two different augers

iii. Single chamber with oil as heating medium iv. Single chamber with water as heating medium

5.2. PROPOSED METHOD 1

The first proposed method is double chamber with hydraulic or pneumatic piston arrangement. The concept of this method is shown in fig. 5.1.

Fig. 5.1: Double chamber with hydraulic or pneumatic piston

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In this method, mixing and extrusion process takes place in a separate chamber. In the mixing chamber, through the hopper the clay in the form of chips (tiny pieces) are fed and mix together. Meantime, the mixing chamber is heated with the help of electric heaters around the chamber. Hence the clay will attain its soft butter temperature (60 °C). Inside the mixing chamber, there is an auger with usual type of blades which is used in the commercial models of pugmills. It is driven by an electric motor. Then the bridge between both chambers will be open and the clay moves to extrusion chamber. Inside the extrusion chamber, there is a piston which is actuated by hydraulic or pneumatic system. At first it compresses the clay to stick all the particles together, when the piston reaches a particular position in the extrusion chamber, the nozzle of the chamber gets open and the clay will come out of the chamber in the form of molded cylinder.

The whole process is simple and is simple in construction. On the other hand, it requires lot of space to hold two chambers as well as the driving units. Since it has two different types of driving unit system (electric and hydraulic/pneumatic), this method is costly when compared with other systems.

5.3. PROPOSED METHOD 2

The second proposed method is double chamber with two different augers. The concept of this method is shown in fig. 5.2.

In this method, mixing and extrusion process takes place in a separate chamber. In the mixing chamber, through the hopper the clay in the form of chips (tiny pieces) are fed and mix together. Meantime, the mixing chamber is heated with the help of electric heaters around the chamber. Hence the clay will attain its soft butter temperature (60 °C). Inside the mixing chamber, there is an auger with usual type of blades which is used in the commercial models of pugmills. It is driven by an electric motor. Then the bridge between both chambers will be open and the clay moves to extrusion chamber. Inside the extrusion chamber, there is the second auger resembles a screw conveyor which is actuated by electric motor. At first it compresses the clay to stick all the particles together for some time. After that, the nozzle of the chamber gets open and the clay will come out of the chamber in the form of molded cylinder.

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Fig. 5.2: Double chamber with two different augers

The process is not so complex and it requires a single driving unit to drive both augers.

But the driving motor needs more power to drive both auger. On the other hand, it requires a lot of space to hold two chambers as well as the driving units. Since it has two different types of augers (auger with blades and auger with flight), this method is costly when compared with other systems.

5.4. PROPOSED METHOD 3

The third proposed method is single chamber with oil as heating medium. The concept of this method is shown in fig. 5.3.

In this method, mixing and extrusion process takes place in the same chamber. In the mixing and extrusion chambers, through the hopper the clay in the form of chips (tiny pieces) are fed and compress together due to the action of auger rotation towards the closed end of the chamber. Meantime, the chamber is heated with oil which flowing around the chamber casing.

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The oil is heated with some kind of heating coils. Hence the clay will attain its soft butter temperature (60 °C). When the chamber gets the extrusion signal from the operator, the nozzle of the chamber gets open and the direction of rotation of the motor will get reversed and the particles move towards the nozzle. So that, the clay will come out of the chamber in the form of molded cylinder.

Fig. 5.3: Single chamber with oil as heating medium

The whole process is simple and is simple in construction. It doesn’t require large space when compared to others. On the other hand, maintenance of oil passage and control its leaking makes the complexity. When compared to the electric heaters, heating coil takes long time to heat the oil to its required temperature. Used oil should be replaced for every particular interval time. So, the maintenance cost is high for this system.

5.5. PROPOSED METHOD 4

The fourth proposed method is single chamber with water as heating medium. The concept of this method is shown in fig. 5.4.

This method is very much similar to the proposed method 3 (single chamber with oil as heating medium). The aim of this method to nullify the drawback of proposed method 3. The

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only difference between both methods is the heating medium. In this method, water is used as heating medium instead of oil.

Fig. 5.4: Single chamber with water as heating medium

Here, mixing and extrusion process takes place in the same chamber. In the mixing and extrusion chamber, through the hopper the clay in the form of chips (tiny pieces) are fed and compress together due to the action of auger rotation towards the closed end of the chamber.

Meantime, the chamber is heated with water which flowing around the chamber casing. The water is heated with some kind of heating coils. Hence the clay will attain its soft butter temperature (60 °C). When the chamber gets the extrusion signal from the operator, the nozzle of the chamber gets open and the direction of rotation of the motor will get reversed and the particles move towards the nozzle. So that, the clay will come out of the chamber in the form of molded cylinder.

Simplest in construction among the four methods. It doesn’t require large space when compared to others. On the other hand, maintenance of water passage and control its leaking makes the complexity. Water is a natural resource and hence the system remains cheaper than of all the others.

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5.6. ANALYSIS ON PROPOSALS

Based on different parameters like, number of chambers, number of driving system, mode of power, power requirement, heating element, principle of heat transfer, time, space consumption, output efficiency, complexity, maintenance and investment cost, an analysis is shown on the table 5.1.

S. No. Parameters Method 1 Method 2 Method 3 Method 4

1 Number of Chambers 2 2 1 1

2 Number of Driving

System 2 1 1 1

3 Mode of Power

Electric and Hydraulic /

Pneumatic

Electric Electric Electric

4 Power Requirement Very high High Medium Medium

5 Heating Element Electric Heaters

Electric Heaters

Heating Coil (for

Oil)

Heating Coil (for

Water) 6 Principle of Heat

Transfer Conduction Conduction Conduction,

Convection

Conduction, Convection

7 Time High High Medium Less

8 Space Consumption More More Less Less

9 Output Efficiency Good Good Very good Very good

10 Complexity High Medium Medium Low

11 Maintenance High High Medium Low

12 Investment Cost High Medium Medium Low

Table 5.1: Analysis on Proposals

From the table 5.1, it shows legibly that method 4 (single chamber with water as heating medium) is the optimal solution among all the methods.

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6. CALCULATION OF REQUIRED PARAMETERS 6.1. TARGET OF RECYCLING EQUIPMENT

SVOTT requires a recycling equipment for the Marsclay with the output of 100 kg per hour. So, the target is set as 100 kg per hour and the rest of the required parameters are calculated for the proposed method 4. The input for the equipment is non-uniform tiny pieces of clay as shown in fig.6.1. The output from the equipment should be molded cylinder with diameter of 60 mm and length of 250 mm as shown in fig.3.2.

Fig. 6.1: Clay Chips

6.2. TESTING FOR THERMAL CONDUCTIVITY OF CLAY

Before proceeding to the design and numerical basic calculations, we should ensure about the method will be successful or not. If the thermal conductivity is almost equal to zero, the principle of transferring the heat from the water to the clay is not possible. In order to find the real thermal conductivity of Marsclay, the specimen undergone the test for its conductivity value in Heat Flow Meter with the help of Energetics Department of Technical University of Liberec (TUL). Thanks to Ing. Jan Novosád, M.Sc., for spending his precious time with me to do this testing in his laboratory.

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Fig. 6.2: HFM arrangement in TUL Laboratory

Heat Flow Meter – HFM 436 Lambda is an instrument used to determine the thermal conductivity of materials with high precision. Heat Flow Meters (HFM) are exact, fast and easy-to-use instruments for measuring the thermal conductivity (k) of low conductivity materials such as insulations.

Fig. 6.3: Principle of HFM^[11]

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A specimen is placed between a hot and a cold plate, and the heat flow created by the well-defined temperature difference is measured with a heat flux sensor. The HFM 436 Lambda series owe its precision and speed of measurement to the patented temperature control and heat flux measurement technology. Test results are available within minutes, with outstanding accuracy and repeatability.^[11]

Fig. 6.4: Clay specimen for testing

At first, a specimen of Marsclay is made with the dimensions of 11 cm x 11 cm x 2 cm.

Measurement was defined to reach the temperature difference 20°C (30°C at the top surface and 10°C at the bottom surface). It is tested for its thermal conductivity. Measured data were obtained as time dependent. So, in the beginning of measurement, the values are rough.

Because they are affected by the effects of thermal stabilization.

Fig. 6.5: Thermal conductivity test on Marsclay

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72 iterations are made within one hour of time. Results are attached as annexure to this

thesis. Finally, the thermal conductivity of Marsclay is found out which is equal to 1.17 W/mK. Sample results are shown in the following table 6.1.

Time dX TUpper TLower QUpper QLower K(avg) 10:07:51 AM 2.5986 34.01 14.13 12924 12747 1.17192 10:08:28 AM 2.5987 34.01 14.12 12932 12749 1.17192 10:09:06 AM 2.5985 34 14.11 12926 12737 1.17169 10:09:43 AM 2.5986 34.03 14.1 12921 12731 1.17169 10:10:21 AM 2.5986 34.02 14.11 12929 12733 1.17162 10:10:58 AM 2.5987 34.03 14.11 12925 12726 1.17154 10:11:35 AM 2.5985 34.05 14.13 12927 12722 1.17154 10:12:13 AM 2.5986 34.05 14.12 13011 12777 1.17147 10:12:50 AM 2.5987 34.06 14.11 13031 12794 1.17143 10:13:28 AM 2.5986 34.07 14.1 13020 12786 1.17143 10:14:05 AM 2.5987 34.04 14.08 13008 12777 1.1714 10:14:43 AM 2.5986 34.07 14.1 12998 12767 1.1714 10:15:20 AM 2.5987 34.06 14.11 13006 12769 1.17138 10:15:58 AM 2.5983 34.08 14.12 13021 12789 1.17137 10:16:35 AM 2.5986 34.08 14.11 13000 12761 1.17137 10:17:13 AM 2.5986 34.06 14.11 12995 12751 1.17135

Table 6.1: Results of HFM

6.3. VOLUMETRIC CALCULATIONS

The total chamber is split into 3 sections in order to easy clean and for maintenance works. First section consists of end part of chamber, second section consists chamber with hopper and third section consists of nozzle. All sections are having approximately 0.85 m length. For all the three sections, the calculations are made separately. The calculations represented in this section are for section 1. A schematic cross-sectional view of the recycling equipment is shown in the fig.6.6. Cycle time for one batch is assumed as 2 hours. For each cycle, the output should be minimum 200 kg.

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Fig. 6.6: Schematic cross-sectional view of recycling equipment Basic dimensions of the clay chamber 1 is given below in the table 6.2.

S.No. Parameter Notation Value Unit Value Unit

1 Length of Clay Chamber 1 L1 850 mm 0.85 m

2 Radius of auger shaft ra 15 mm 0.015 m

3 Inner radius of clay chamber IN r1 200 mm 0.2 m

4 Outer radius of clay chamber IN r2 205 mm 0.205 m 5 Inner radius of clay chamber OUT r3 225 mm 0.225 m 6 Outer radius of clay chamber OUT r4 230 mm 0.23 m

7 Outer radius of Insulation r5 240 mm 0.24 m

Table 6.2: Basic dimensions of clay chamber 1

Input temperature conditions and physical & thermal properties of the materials which is present in clay chamber 1 is given below in the table 6.3.

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S.No. Parameter Notation Value Unit Value Unit

1 Temperature of ambient air Tb 25 °C 298.15 K

2 Temperature at inner radius of CC IN T1 65 °C 338.15 K

3 Thermal Conductivity of clay ka HFM Test 1.17 W/mK

4 HTC of air hb Range 10 to 100 50 W/m²K

5 HTC of water hw Range 500 to

10000 600 W/m²K

6 Thermal Conductivity of Al Alloy

2024-T6 k1 HMT DB 1^[12] 177 W/mK

7 Thermal Conductivity of SS AISI 304 k3 HMT DB 3^[12] 14.9 W/mK 8 Thermal Conductivity of Rockwool

Insulation k4 Rockwool^[13] 0.05 W/mK

9 Heat Flow Q Pneutherm^[14] 1500 W

10 Density of Clay ρc Staedtler^[5] 1450 kg/m³

11 Density of Water ρw HMT DB 22^[12] 1000 kg/m³

12 Specific heat of clay Cpc HMT DB 13^[12] 880 J/kgK

13 Specific heat of water Cpw HMT DB 22^[12] 4178 J/kgK

Table 6.3: Material properties and input condition

Approximated volume and mass of the clay and water inside the clay chamber 1 are calculated below in the table 6.4 and table 6.5.

Formulae used in the table 4.3 and table 4.4 are given below:

Volume, 𝑉 = 𝜋(𝑟_𝑚𝑎𝑥² − 𝑟_𝑚𝑖𝑛² )𝐿₁ (6.1)

Useful volume, 𝑉_𝑢 = 0.8 × 𝑉 (because of flight and heating coil) (6.2)

Mass, 𝑚 = 𝜌𝑉_𝑢 (6.3)

Material

r1 ra L1 V Vu ρc mc

m m m m³ m³ kg/m³ kg

Clay 0.2 0.015 0.85 0.10621 0.08497 1450 123.21 Table 6.4: Volumetric Calculations of Clay

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Material

r3 r2 L1 V Vu ρw mw

m m m m³ m³ kg/m³ l

Water 0.225 0.205 0.85 0.02297 0.01837 1000 18.37 Table 6.5: Volumetric Calculations of Water

6.4. TEMPERATURE DISTRIBUTION ACROSS THE CHAMBER

Temperature on the walls of the chamber and the water are calculated in the table 6.5.

Formulae used in the table 6.6 are given below and the formula is taken from HMT DB^[12] page number 44 and 46:

Heat flow, 𝑄 = ^∆𝑇

𝑅 (6.4)

where, Thermal resistance, 𝑅 = 𝑅₁+ 𝑅_𝑤 + 𝑅₂+ 𝑅₃ (6.5)

𝑅₁ = ¹

2𝜋𝐿₁

×

_𝑘¹

1

× 𝑙𝑛 (

^𝑟_𝑟²

1

)

(6.6)

𝑅_𝑤 = ¹

2𝜋𝐿₁

×

_ℎ¹

𝑤𝑟₂ (6.7)

𝑅₂ = ¹

2𝜋𝐿₁

×

_ℎ¹

𝑤𝑟₃ (6.8)

𝑅₃ = ¹

2𝜋𝐿₁

×

_𝑘¹

3

× 𝑙𝑛 (

^𝑟_𝑟⁴

3

)

(6.9)

𝑅_𝑏 = ¹

2𝜋𝐿₁

×

_ℎ¹

𝑏𝑟₄ (6.10)

𝑅₄ = ¹

2𝜋𝐿₁

×

¹

𝑘₄

× 𝑙𝑛 (

^𝑟⁵

𝑟₄

)

^(6.11)

Temperature, 𝑇₂ = 𝑄𝑅₁+ 𝑇₁ (6.12)

𝑇_𝑤 = 𝑄𝑅_𝑤+ 𝑇₂ (6.13)

𝑇₃ = 𝑇_𝑤− 𝑄𝑅₂ (6.14)

𝑇₄ = 𝑇₃− 𝑄𝑅₃ (6.15)

𝑇₅ = 𝑇₄− 𝑄𝑅₄ (6.16)

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Notation Value Unit

R1 0.000 K/W

Rw 0.002 K/W

R2 0.001 K/W

R3 0.000 K/W

R4 0.032 K/W

Rb 0.016 K/W

R 0.019 K/W

T2 338.19 K Tw 340.47 K T3 338.39 K T4 337.98 K T5 289.34 K

Table 6.6: Temperature distribution across the chamber

6.5. SELECTION OF DRIVE

Based on the dimensions of machine which is designed and the required capacity per hour, required speed of the screw conveyor can be found out. According to the required speed and power required to transport the material and to rotate the screw conveyor, motor is selected through the following formulae^[15].

Conveyor nozzle area, 𝑠 =

𝜆

^𝜋𝐷₄^𝑁² (6.17)

=

0.7 ×

^𝜋×0.06₄ ²

𝒔 = 𝟏. 𝟗𝟕𝟗 × 𝟏𝟎^−𝟑 𝒎^𝟐 where, 𝜆 → coefficient of trough loading

𝐷_𝑁 → diameter of the nozzle (m)

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Transported material flux, 𝑄_𝑐 = 3600 × 𝑠 ×^𝑝𝑛₆₀

× 𝜌

_𝑐

× 𝐾

(6.18) 0.1 = 3600 × 1.979 × 10⁻³×^0.3×𝑛₆₀ × 1.45 × 1

𝒏 = 𝟏. 𝟗𝟒 𝒓𝒑𝒎 ≈ 𝟐 𝒓𝒑𝒎 where, 𝑄_𝑐 → transported capacity (tonnes/hr)

𝑝 → pitch of screw conveyor (m) 𝑛 → speed of screw conveyor (rpm) 𝜌_𝑐 → density of clay (tonnes/m³)

𝐾 → coefficient of conveyor housing inclination (for 0°, K = 1)^[15]

Power required to transport the material horizontally, 𝑃_𝐻 =

𝐶

₀^𝑄^𝑐^𝐿

367 (6.19)

= 4 ×

^{100 × 2.45}

367

𝑷_𝑯 = 𝟐. 𝟔𝟕 𝒌𝑾 where, 𝐶₀ → material resistance coefficient (=4, for clay)^[15]

𝑄_𝑐 → transported capacity (kg/hr)

𝐿 → installed length of screw conveyor (=2.45 m from CAD Data)

Power required to operate unloaded screw, 𝑃_𝑁 = ^𝑑^𝑠^𝐿

20 (6.20)

=

^0.4×2.45

20

𝑷_𝑵 = 𝟎. 𝟎𝟒𝟗 𝒌𝑾 where, 𝑑_𝑠 → diameter of the screw

Minimum power required for the motor, 𝑃 = 𝑃_𝐻+ 𝑃_𝑁 (6.21)

= 2.67 + 0.049

𝑷 = 𝟐. 𝟕𝟐 𝒌𝑾 ≈ 𝟑. 𝟔𝟓 𝒉𝒑

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Required torque, 𝑇 = ^60𝑃

2𝜋𝑛 (6.22)

= ^60×2.72×10

3 2×𝜋×2

𝑻 = 𝟏𝟐𝟗𝟖𝟕. 𝟎𝟒 𝑵𝒎

For speed n = 2 rpm and power P = 3.65 hp, from NORD Drive Systems, SK 6382VX - 100AH/4^[16] Shaft mount motor with the gearbox is selected. The specifications of the selected motor are

✓ Power - 3 kW

✓ Input speed - 1425 rpm

✓ Gear ratio - 393.19

✓ Output speed - 3.7 rpm

✓ Voltage - 230/400 V

✓ Torque - 68530 Nm

Selected motor has higher torque and power than the required torque and power.

Specifications of the drive is attached as annexure^[17].

6.6. CALCULATION OF OPERATING TIME

The total time to heat the clay and water from the starting temperature to the final temperature are calculated in the table 6.7 and table 6.8. Starting temperatures are set as the room temperature (20°C) and the final temperature of clay is set as working temperature of clay (60°C) and for the water as Tw (67.32°C = 340.47K).

Formulae used in the table 4.5 are given below:

Heat energy, 𝑞 = 𝑚𝐶_𝑝(𝑇_𝑚𝑎𝑥− 𝑇_𝑚𝑖𝑛) (6.23)

Time, 𝑡 = ^𝑞

𝑄 (6.24)

Material

mc Cpc Tmax Tmin qc Q tc

kg J/kgK °C °C J W s min

Clay 123.21 880 60 20 4336992 1500 2891.33 48.19 Table 6.7: Time required for heating the clay

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Material

mw Cpw Tmax Tmin qw Q tw

kg J/kgK °C °C J W s min

Water 18.37 4178 67.32 20 3632004 1500 2421.34 40.36 Table 6.8: Time required for heating the water

For a circular trajectory, the length traveled in one rotation is equal to the circumference of the circle.

Length extruded in one rotation of conveyor, 𝑙 = 2𝜋𝑟 (6.25)

= 2 × 𝜋 × 0.03 𝒍 = 𝟎. 𝟏𝟖𝟖𝟓 𝒎/𝒓𝒐𝒕

Relation between the linear velocity, extruded length per minute and speed can be written as

𝑙𝑖𝑛𝑒𝑎𝑟 𝑣𝑒𝑙𝑜𝑐𝑖𝑡𝑦, 𝑣 (𝑚/𝑚𝑖𝑛)

𝑙𝑒𝑛𝑔𝑡ℎ 𝑒𝑥𝑡𝑟𝑢𝑑𝑒𝑑 𝑖𝑛 𝑜𝑛𝑒 𝑟𝑜𝑡𝑎𝑡𝑖𝑜𝑛 (𝑚/𝑟𝑜𝑡) = 𝑠𝑝𝑒𝑒𝑑 (𝑟𝑝𝑚) (6.26)

𝑣

0.1885 = 3.7

𝒗 = 𝟎. 𝟔𝟗𝟕𝟒𝟓 𝒎/𝒎𝒊𝒏

Output from the machine should be molded cylinder of Marsclay in the shape of cylinder with the dimensions of diameter 60 mm and 240 mm (0.24 m) in length. Each cylinder weighs about 1 kg. Machine can be safely loaded with 200 kg of Marsclay. Therefore, total number of cylinders that can be extruded from the machine is 200 cylinders for a batch.

Length of total extruded clay = length of one-cylinder x 200 (6.27)

= 0.24 x 200 Length of total extruded clay = 48 m

If the machine can extrude 0.697 m/min (v), then for 48 m of clay, it will take 68.87 minutes, approximately 70 minutes.

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Approximately, the time required to heat the water from 20 °C to 67.32 °C is 40 minutes and the time required to transfer the heat to the clay is 48 minutes. After this 88 minutes, the equipment turns to the extrusion mode and approximately it will take 70 minutes. Totally, from the starting stage of machine up to the extrusion of product, the machine will take approximately 160 minutes (2 hours and 40 minutes). But, heating of water is a preparatory stage. So, the cycle of operation includes only 48 minutes for heating the clay and 70 minutes for extruding the clay ie. approximately 2 hours.

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7. CONSTRUCTION AND WORKING

7.1. CONSTRUCTION OF MARSCLAY RECYCLING MACHINE

As already stated in chapter 6.3, the whole chamber is split into 3 sections in order to disassemble and assemble and for an ease maintenance. In this total construction, most of the parts are fabricated by Stainless Steel and Aluminium Alloy and its drawings are attached as annexures and isometric views are provided in this section. Some of them are standard parts and the specification or data sheet are attached as annexures. Marsclay recycling machine is depicted in the below picture fig.7.1.

Fig. 7.1: 3D Isometric View of Marsclay Recycling Machine

First section consists of end part of chamber, second section consists chamber with hopper and third section consists of nozzle. Approximately, this machine is having the dimensions of 3.5 m in length, 0.75 m in height and 0.7 m in width (0.7m x 0.8m x 3.5m).

2D drawing sheets are attached as the annexure with the technical information of the components which are specially designed for this machine. 3D CAD Models for the standard components are downloaded from the website Traceparts^{[18] [19]}.

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7.2. CLAY CHAMBER ASSEMBLY

Each clay chamber section consists of so many important parts which have its own purpose and unique style. The parts in the clay chamber assembly are listed below.

a) Inner chamber b) Outer chamber c) Heating coil

d) Clay chamber connector e) Hopper and hopper lid f) Chamber support g) Ball valve

h) Hinges, lock rod and fasteners

Fig. 7.2: Clay Chamber Assembly with Hopper

Fig.7.2 depicts the clay chamber assembly. At first, a layer of non-leakage coating like FX200 Celsius Silicone High Temperature Aluminum Finish^[20] coating which is capable of withstanding 250°C, is applied over the inner and outer chamber. The steps to be followed while assembling the clay chamber are as follows:

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1. Fix the heating coil inside the outer chamber with the equipment provided with the heating coil.

2. Assemble the outer chamber to the clay chamber connector and tight it with 24 sets of ISO 1207 screw M6X14 on both the sides.

3. Now join this assembly with the inner chamber and tight it with another 24 sets of ISO 1207 screw M6X14 on both sides.

4. Fix the inlet and outlet ball valves on the top and bottom sides of the outer chamber.

5. If hopper is not there, continue with step number 8. Otherwise, attach the hinges with the hopper using the screws provided with the hinges.

6. Attach the hopper lid with the hinges which is already connected to the hopper and also insert the lock rod hopper to close the lid. Now the hopper assembly is ready.

7. Connect the hopper in its place and tight it with 12 sets of ISO 1207 screw M2X10. If needed weld it.

8. Connect the chamber support to the clay chamber assembly with the help of 12 sets of ISO 1207 screw M8X25 horizontally and vertically and 10 sets of ISO 1207 screw M8X25 in the nozzle section.

7.2.1. INNER CHAMBER

Fig. 7.3: Inner chamber

Inner chamber is a 5mm Aluminium alloy sheet metal with the outer diameter of 410 mm. Additionally, it is having 24 number of holes for the M6 screws. 3D Isometric model of the inner chamber is showing on the fig.7.3.

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7.2.2. OUTER CHAMBER

Fig. 7.4: Outer Chamber

Outer chamber is a 5mm stainless steel sheet metal with the outer diameter of 460 mm.

As like inner chamber, it is also having 24 number of holes for the M6 screws and M8 screws.

Additionally, it is having the arms to support with the chamber support. 3D Isometric model of the inner chamber is showing on the fig.7.4.

7.2.3. HEATING COIL

Fig. 7.5: Heating Coil

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Heating coil is a standard part which is a product of Pneutherm limited^[14]. It is a tubular heater series edition. Sheet contains the technical information is attached on the annexure.

Somehow, they need a profile of tubular heater from the customer. For that, profile of the heating coil is simply depicted on the fig.7.5. The assembling components and wiring will be provided by the Pneutherm company for this heating coil. This heating coil is made up of 8 mm diameter copper rod.

7.2.4. CLAY CHAMBER CONNECTOR

Clay chamber connector used to connect one chamber section with other section of clay chamber. This connector is having holes for M6 screw and also holes for M8 bolts in order to connect with another clay chamber connector. It is also in the shape of hollow cylinder with the outer diameter of 550 mm. It is made up of steel and show in the fig.7.6.

Fig. 7.6: Clay Chamber Connector

7.2.5. HOPPER AND HOPPER LID

Hopper is used to feed the clay to the machine. It is a wide opened part. During the operation, it must be closed by a lid. A specially designed lid and hopper are shown in the fig.7.7. Hopper is made up of 5 mm sheet metal connected with welds.

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Fig. 7.7: Hopper with Hopper Lid

7.2.6. CHAMBER SUPPORT

Fig. 7.8: Chamber Support

Chamber supports are used to hold the clay chamber. It is connected with the arm of outer chamber. It is a special design to hold this chamber. The main purpose of this chamber support is to withstand the load of the total machine and to absorb the shocks and vibrations which is made by the machine. It has the holes for M8 screws also. Chamber support is shown in the fig.7.8.

Design of Equipment to Recycle Marsclay

Design of Equipment to Recycle Marsclay

Diplomová práce

Design of Equipment to Recycle Marsclay

Master thesis

Declaration

ACKNOWLEDGEMENT

TABLE OF CONTENTS

LIST OF FIGURES

LIST OF TABLES

LIST OF ABBREVIATIONS

LIST OF SYMBOLS

r

r

r

r

r

r

1. INTRODUCTION

2. AIM OF THESIS

3. MARSCLAY AND SVOTT 3.1. WHAT IS CLAY?

3.2. CLAY IN AUTOMOBILE INDUSTRY

3.3. ABOUT SVOTT

3.4. MARSCLAY

4. LITERATURE REVIEW 4.1. WHAT IS PUGMILL?

4.2. PUGMILLS FROM THE HISTORY

4.3. COMMERCIAL PUGMILLS

4.4. CONCLUSION FROM THE LITERATURE REVIEW

5. PROPOSED METHODS

5.1. INTRODUCTION TO PROPOSED METHODS

5.2. PROPOSED METHOD 1

5.3. PROPOSED METHOD 2

5.4. PROPOSED METHOD 3

5.5. PROPOSED METHOD 4

5.6. ANALYSIS ON PROPOSALS

S.

No. Parameters Method 1 Method 2 Method 3 Method 4

6. CALCULATION OF REQUIRED PARAMETERS 6.1. TARGET OF RECYCLING EQUIPMENT

6.2. TESTING FOR THERMAL CONDUCTIVITY OF CLAY

6.3. VOLUMETRIC CALCULATIONS

6.4. TEMPERATURE DISTRIBUTION ACROSS THE CHAMBER

×

× 𝑙𝑛 (

)

×

×

×

× 𝑙𝑛 (

)

×

×

× 𝑙𝑛 (

)

6.5. SELECTION OF DRIVE

𝜆

0.7 ×

× 𝜌

× 𝐾

𝐶

= 4 ×

=

6.6. CALCULATION OF OPERATING TIME

7. CONSTRUCTION AND WORKING

7.1. CONSTRUCTION OF MARSCLAY RECYCLING MACHINE

7.2. CLAY CHAMBER ASSEMBLY