Designing a hemp seed press for hemp oil hemp cake production
Faculty of engineering and physical sciences
(eng1034)
Design Make and Evaluate project
Hemp seed press for hemp oil hemp cake production
Design specification
By
Group F1
Jonathan Conway,
Petros Akridis,
Chris Loeber,
Philip Hobbs,
Ng Hung Man,
Andrew Morgan,
Senthan Sivabalasubramaniam
DME Project 1
Group F1
The Design Brief
The objective for the design is to produce a mechanical machine which is capable of crushing or roll hemp seed into oil and the cake which the by product of the crushing process. The design must also be able to collect the cake to further use. The machines will be produced for third world country and the people in these countries.
Research plan
Research can be done into may areas including the history of oil production as this process has been use for 100's of years in are history. However there are other sources for the data such as magazine articles, the internet and book source showing the historical patents for the last few years. Therefore the following sources will be considered in order to get ideas for the design of the product.
* Book
* Internet
* Magazines
* Historical data
Anthropometrics
Ergonomics
Design ideas
Design manufacture
Size of design
Time plan
Design Specification
The idea of this project is to design, make and evaluate a purely mechanical system in order to press and extract the oil from hemp seeds using a cold pressing method.
To begin, a design specification is required. The design specification, based on the customer's needs, is to understand with more clarity what is required of the design and so it is essential for the design process to start.
The design specifications have been divided into four parts:
* The first part is to establish the purpose and the functions of this product.
* The second part is the requirements of the material, the conditions and the applications are a strong factor when choosing a material to use.
* The third part is Manufacture, this looks at how the mechanical system should be constructed with the users in mind.
* The final part is Safety and Hygiene. The extracted oil is to be used for food preparation etc, so hygiene is a factor to be aware of.
Background
Hemp is a name that is used in order to refer to at the whole species of the plants known as Cannabis. Hemp products have been used for over 10,000 years; they are useful for making ropes and clothes due to their strong fiber. I it is also used for paint, varnishes, medical purposes, food and these days even fuel.
As a food, hemp seed contains 70% of the cholesterol-fighting essential fatty acids; this is the highest of any other seed oil. That makes it a very healthy nutritional food that can be consumed on a daily basis.
As paint hemp seed oil dries quickly, leaving a thin elastic film.
In medical uses, hemp is used to produce a drug which it has psychoactive properties which doctors used to cure personality disorders such as melancholia. But the overuse of this drug and its bad effects has driven many countries to forbid it.
Also, as a bio-fuel, it is 70% cleaner than diesel and petrol, making it a good alternative to help prevent global warming.
Sequence Of use and its implications for the specification
Operation
Implication
Storage
The product must be small enough to store, but at the same time have a sufficient capacity to produce reasonable amounts of oil.
Lifting into transportation
Max load of 15kg, requires 2 people to lift safely.
Securing for transportation
The product must be robust for transport, securing mechanisms or brakes would be required.
Suitable site
A flat, stable surface would be required. Either self standing, or mounted onto a suitable surface.
Stability
As above, it must be able to stand freely, with the ability to cope with knocks, wind etc.
Operation without injury
Must be designed in a way which minimises risk of harm, moving parts concealed etc.
Cleaning and maintenance
All parts required for cleaning and maintenance should be easily accessible. And completed within 15 minutes
Lifespan
The product must last a minimum of 5 years of 7 hours constant use per day without corroding or failing.
Design Specifications:
. Purpose & Functions
a) The product must not exceed the mass of 15 Kg, making it easy to transport and move around when it is required.
b) It must be powered by manual or mechanical means. Due to lack of power sources in developing countries a non electrical means is required. Either man/animal power or use of natural resources (water, wind etc.).
c) It must completely separate the hemp oil from the left over cake, preserving both, in order to use them for different applications.
d) The service time must not exceed 15 minutes. Minimal or standard tools should be required in order to access main parts.
e) Be designed with ergonomics in mind, it must be easy to reach and easy to use parts.
f) The mechanism should use cold-pressed technology because of the customer demand to produce cold pressed hemp oil.
g) Have a running efficiency of at least 40-50% in order to produce a useful amount of oil and cake.
2. Material
a) The product must be able to cope with temperatures ranging between -28 and +44 ?C including possible adverse conditions.
b) Have a life expectancy of at least 5 years with an expected service every 2 years.
c) Be created using as many existing standard parts and tools as possible. Specialist tools and parts are expensive, using standard tools and parts would cut down on cost and service time.
d) Be corrosion resistant, it must last 5 years and 7 hours of continuous use without needing parts to be replaced or the mechanism catastrophically failing.
e) Recommended materials to be used are iron and steel. Recommended by customer because these are easy access materials around the world.
f) Structural integrity must be maintained throughout heating and cooling cycles due to the weather.
g) Deflections due to loading and heating must be minimized (acceptable limits for particular parts under condition of use).
h) Materials used should be hygienic and easy to clean after use.
3. Manufacture
a) The product must be suitable for use by untrained users.
b) Be a single contained unit when it is assembled. No additional equipment should be required in order to operate the product.
c) Not exceed a production cost of £60.
d) Dimensions are not specified, however it must be able to produce as much oil as the weight allows.
4. Safety & Hygiene
a) No specialized training should be required to use this product. Operating instructions should be sufficient.
b) Be safe to use with minimal safety equipment required. (PEE Optional).
c) Comply with British engineering standards. Must comply with Health and Safety at Work Act 1974, Control of Substances Hazardous to health (COSHH) and the Provision and Use of Work Equipment Regulations (PUWER).
d) This product must be hygienic when separating oil from the cake. Must comply with the Food Standards Agency (FSA).
e) Must be stable on rough or even terrain to maximize safety.
Concept and Design
Ideas for the creation of a press
Mechanism for pressing
Screw press
Child labour
Hydraulic press
Lever press
Pneumatic press
Crushing
Rolling
Cider press (screw to press the weight into the base)
Stone mill
Materials
Stainless Steel
Mild steel
Wood
Iron
Stone
Aluminium
Polymers
Ceramics
High tolerance
High and low temp
Light
Hygienic
Reusable materials
Method of production
Casting
Casket
Moulding
Forging
Carving
Power
Manual
Human
Animal
Wind
Water
Gravity
Run off hemp oil
Battery (electricity)
Solar
Geothermal
Steam (Combustion)
Quantity of Seeds
1kg -5kg
Efficiency
40-50%
First Ideas
Vertical Screw Press
As the name suggests, this idea uses a large screw thread in order to apply pressure onto a surface.
This technique has already been used for many years for a wide variety of industries, including the crushing of hop seeds in breweries and early forms of bread making.
*See image 002
Conveyor Press
This consists of a series of rollers which compress the material as it travels along a conveyor belt.
This is widely used in the glass pressing and the plate steel manufacturing process.
*See image 003
Hydraulic press
Using the same principals as the vertical screw press, this replaces the threaded shaft with a hydraulic ram, applying the same force onto the pressing surface.
This is a method used for crushing large objects such as vehicles and other redundant machinery.
*See image 004
Vertical Roller ...
This is a preview of the whole essay
*See image 002
Conveyor Press
This consists of a series of rollers which compress the material as it travels along a conveyor belt.
This is widely used in the glass pressing and the plate steel manufacturing process.
*See image 003
Hydraulic press
Using the same principals as the vertical screw press, this replaces the threaded shaft with a hydraulic ram, applying the same force onto the pressing surface.
This is a method used for crushing large objects such as vehicles and other redundant machinery.
*See image 004
Vertical Roller Press
Using two or more rollers, items are gravity fed into the system. Two large horizontal rollers then crush the material as it passes between them.
*See image 001
Horizontal Screw Press
As the material is fed into the system, the threaded shaft forces the material to become crushed against the walls of the press.
This is the primary technique used in Powered seed presses.
*See image 005
Cider Press
As the name suggests, this is using the same method as a Cider Press, it uses multiple layers for the material to be placed on. The layers then compress against each other.
This is used for cider production, which consists of crushing apples.
*See image 006
Selection of Primary Idea
Using various selection methods, it was decided that the Vertical Roller Press was the best solution based on the design brief and specification.
One of the methods used to decide the most appropriate concept was a Weighted Factor Table. This consisted of a list of all relevant properties (See Design Specification) and then weighting these factors relative to each other. By ranking each idea's specific ability to perform the necessary property compared to the others, a sensible solution could be ascertained. (See Table 101)
The vertical roller press came out on top because; it provided the easiest construction and use for the greatest quantity of seeds pressed. Whilst also doing relatively well on cost of production and hygiene.
Layout of Proposed Scheme
The press will consist of a large cavity and a small cavity.
The large cavity will contain the rollers and separation device.
Furthermore the smaller cavity will contain the necessary mechanism to drive the rollers.
On top of the large cavity will be the hopper which feeds the seeds into the mechanism using gravity.
Underneath the mechanism there will be two separate reciprocals, one for the oil and one for the cake.
Design
The press is constructed by a simple box frame attached to a base. The frame supports the shafts and bearings in the mechanism. The frame also supports the panelling for the press and acts as a mounting for the hopper.
The mechanism consists of a two interlocking cogs driving two small shafts, attached to which are two sets of sprocket gears powering the larger shafts upon which the rollers are attached.
Part listing
Base - Sturdy steel plate acting as a support for the entire structure.
Framework - Square Box section tubing made of steel attached together via welding
Panelling - Light weight wood panelling attached to the framework with bolts.
Shafts - 20mm diameter steel shafts
Rollers - 200mm Steel Tubing with steel plate supports.
Handle - Simple handle consisting of a support and hand hold.
Bearing housing - Made from steel, these hold the circular ball bearings.
Hopper - Rolled sheet steel in the form of a cone.
Method of Operation
Seeds are placed inside the hopper, where gravity will feed them onto the counter rotating rollers which pull them through and crush them.
The cake and oil lands upon a grated shelf, this then filters out the oil which seeps through into a collection draw.
Once the two materials are separated they are easily stored for later use.
Plan of Assembly
The assembly will happen with in a four week period. In order to make best use of this time a plan of assembly is beneficial. Also a basic weight prediction will help make sure we keep to the specifications.
Sums and Theories
Weight Prediction
DME original Prediction
. Steel Square Tubing
Properties:
Length = 4000 mm
Width = 25 mm
Thickness = 0.5 mm
Steel density = 7.8 g/cm3
(Also density = 7.8 × 10-3 g/mm3)
Density = mass / Volume
Surface Area = Length × Width
Surface Area = 25 × 25 - 24.5 × 24.5
Surface Area = 24.75 mm2
Volume = Surface Area × Length
Volume = 24.75 × 4000
Volume = 99000 mm3
Mass = density × volume
Mass = 7.8 × 10-3 × 99000
Mass = 772.2 g
2. Steel Plating
Properties:
Length = 2000 mm
Width = 500 mm
Thickness = 1 mm
Steel density = 7.8 × 10-3 g/mm3
Volume = Length × Width × Thickness
Volume = 2000 × 500 × 1
Volume = 106
Mass = density × Volume
Mass = 7.8 × 10-3 × 106
Mass = 7800 g
Mass = 7.8 kg
3. Steel roller shafts
Properties:
Length = 1100 mm
Diameter = 20 mm
Volume = ? × r2 × h
Volume = 345.5752 cm3
Mass = 2.696 kg
4. Rollers Steel Plate
Properties:
Diameter = 200 mm
Thickness = 3 mm
Volume = ? × r2 × h
Volume = 94247.8 mm3
Mass = 735.133 g
Because 2 roller plates
Total Mass = 1.47 kg
5. Hopper
Properties:
Length = 500 mm
Width = 250 mm
Thickness = 3 mm
Volume = 375000 mm3
Mass = 2.925 kg
Bill of Materials
Case
Steel box tubing (25x25mm) 4 metres in length
Steel plating (2000x500mm) thickness of 1.5mm
Steel plating (400x500mm) thickness of 3mm
Steel roller shaft (1200mm) 20mm diameter
00 bolts with nuts length of thread 50mm of diameter 5mm
Draws
Perforated steel (500x500mm)
Steel plate (500x500) thickness of 1.5mm
Rollers
Steel cylinder (400mm) of 200mm diameter £34.00
8 bearings with internal diameter of 200mm RS - 6190339 £44.58
Gears
2x 120mm 60 teeth steel £23.00
2x 40mm gears 40 teeth steel £14.00
Handle
Steel plate (200x20mm) thickness of 10mm
Steel shaft (100mm) 10mm diameter
Hopper
Steel plating (1500x400mm) thickness of 1.5mm
Total steel: £65.00
Total cost: £178.58
Estimated bill of materials is over original specified requirements. However the design reaches all over requirements satisfactorily.
Plan of assembly
Week 1: Start DME Project
Started on discussing the structure of management, the role of each member. Proposed some statement of design, a first draft of the specification, and a plan of work.
Week 2: Specification and Concept design
Design specification and sum up; known the details well, researching. Started to have some concept idea of the design and produced some outline of the project design.
Week 3: Concept design evaluation
Continue the concept design from week 2, made some analyses and appraisal each of the concepts, find out which is the best 2 or 3 concept design will be probably use.
Week 4: Detailed concept evaluation and Finalise selection
Did some detailed drawings, calculations and measurement for the best 2 or 3 schemes. Choose one of the best concept designs for the project.
Week 5: Layout of proposed scheme
Drew a layout of the final design with detailed and did some note of the method of construction and any critical dimensions of the design.
Week 6: Detailed design
Used CAD software to produce a component models
Week 7: Manufacturing drawings
Produced a manufacturing drawing and find out the price of each components and materials that will use on the design.
Week 8: General assembly and preliminary bill of materials
Produced the general assembly of the design, a typed list of all materials and bought in components.
Week 9: Meet Guildford college staff to review the design and modification of design and bill of materials
Final bill of materials, review the chosen materials and manufacturing drawings with Guildford college staff.
Week 10: Draw up production plan
Draw up a manufacturing schedule of the construction for week 11-14, it will be more efficiency.
Week 11: Gathering of materials
Gathering of materials that have ordered in the past few weeks.
Week 12: Cutting and preparing of materials
Prepared the materials for the project, do the frame work and cut it by parts.
Week 13: Cutting and preparing materials + shaft and bearing measurements
Continue cutting and shaping the materials and ordering new shafts and bearings beams and waiting for them to arrive.
Week 14: Final assembly
All the parts are prepared, collected and assembling the project.
Week 15: Evaluating the project
Evaluation
Production Diary
Before the manufacturing process started, all the materials that were ordered before Easter were checked. However, due to 'clerical' errors with the parts list, major design changes had to be made in order to account for available materials, therefore new materials had to be improvised in order to start the process.
The manufacturing process began by making the exterior of the project which consisted of a box. A wooden sheet was acquired and measured to size, then cut using a band saw into 6 pieces.
The first piece was the top surface, the second piece was one of the case panels, the third, fourth and fifth pieces were the additional case panels, the final piece was the bottom of the hemp seed press (Base plate).
When the wooden external panels were cut to size, it was the turn of the L-section Aluminium corner supports. A long aluminium L-shape beam was taken and was cut into four different lengths. Four of these pieces were of length 450 millimetres and had forty-five degree angles cut from each end.
Four more pieces of length 365 millimetres and similarly four of length 335 millimetres were cut with the forty-five degree angles cut into the ends.
Finally two more pieces of length 225 millimetres were cut and had only one of their ends cut to forty-five degrees.
The cuts to the beams were done by hand using a saw. After the L-sections were cut, a protractor was used to calculate the forty-five degree angles in every corner specified. After that the L-sections were marked for cutting from the corner to the centre, a saw was used to cut them. When those L-sections were cut to specifications they were filed by the usual filing method.
During this procedure the rollers were made from a plastic 170 mm diameter gas pipe with thickness of five millimetres. Using a small band saw the gas pipe was cut into two 200 millimetres pieces.
Once the rollers were cut, a sheet of plastic was used to make circular end plates that could be inserted into each end of the rollers. When the four plates were cut, a fifteen millimetre hole was cut into the centre using a mill.
The shafts were the next part to be produced; they were constructed from a three meter long steel bar of fifteen millimetre diameter. They were cut into two pairs of lengths 360 millimetres and 200 millimetres.
When the shafts were finished, the draws were then produced. The first draw was made out of perforated sheet steel, and the second was made from aluminium sheet.
To construct these draws, a net shape was measured and cut to size, and then a bending machine was used to fold the sheets into shape. Then the aluminium draw was welded in order to make it oil tight and filed in order to prevent sharp edges.
The next part to be produced was the bearing housing. This was mad out of fifty millimetre steel bar, machined into shape using a lathe.
All other parts were acquired ready made and altered for use with this product.
Revised Design
"However, due to 'clerical' errors with the parts list, major design changes had to be made in order to account for available materials."
In consequence the design has been redesigned. The press is now made from a wooden box, supported by an aluminium frame. The mechanism is two gears attached to a series of sprocket gears that drive two rollers made from recycled plastic piping of 170 millimetres in diameter. New bearing where ordered from a different supplier with the same internal diameter yet different external diameter this means new bearing housing had to be constructed.
The design uses the same method of crushing and separating the seeds as the original using two large rollers turned by a series of gears and sprockets with chains. However the aluminium frame work is used the wooden panels (instead of the steel panels attaching to a steel frame). The product has been varnished in order to protect the wood from water.
Bill of Materials
Wooden sheet of Ply (3000x2000mm) thickness 10mm free
Aluminium L-shapes 4500mm in length free
Recycled plastic pipe (400mm) of diameter 170mm free
Plastic sheets used to face piping (400x400mm) thickness 5mm free
Steel shafts (1000mm) in length 15mm in diameter free
8 bearings ordered from "Bearing Boys" internal diameter 15mm £28.00
Tin of wood filler and varnish £21.00
2x draw handles £6.00
24 bolts 25mm in thread length 3mm in diameter free
28 wood screws free + £2.00
Pair of hinges £3.00
Steel tubing diameter 50mm in order to make bearing housings free
Total cost: £60.00
However if this went into production there would be other cost of materials which have been estimated overleaf and slight material changes:
Bill of Materials if in full scale production (bulk orders not accounted for)
Wooden sheet of Ply (3000x2000mm) thickness 10mm £12.00
(Steel) L-shapes 4500mm in length £22.50
Recycled plastic pipe (400mm) of diameter 170mm free
Plastic sheets used to face piping (400x400mm) thickness 5mm £9.00
Steel shafts (1000mm) in length 15mm in diameter £6.00
8 bearings ordered from "Bearing Boys" internal diameter 15mm £28.00
Tin of wood filler and varnish £21.00
2x draw handles £6.00
24 bolts 25mm in thread length 3mm in diameter f3.00
28 wood screws £12.00
Pair of hinges £3.00
Steel tubing diameter 50mm in order to make bearing housings f13.00
Total cost: £135.50
Sums and Theories
Weight Prediction
In order to calculate whether or not the proposed design would meet the required specifications the total and individual weights have been worked out. Further more these figures can be used to work out material stress of the design.
. Rollers (Plastic)
The rollers that are going to be used have the following properties:
Each Roller has
Thickness : 5 mm
Length : 200 mm
Diameter : 170 mm
Average density of plastic: 1125 kg/m3
To calculate the mass the equation of density is required
Density = mass / volume
Density is known, so the volume needs to be calculated.
Because the Rollers are Cylinder then equation of Volume is:
Volume = ? × r2 × h
? = 3.14
R = radius of the roller
H = height of the roller (in that occasion length)
Because the Rollers have thickness and the insider is empty, two values of volumes must be subtracted to find the real value of the volume. So Volume1 is the volume of the roller without having the insider empty and the Volume2 is the volume of the rollers when they are 10 mm less diameter.
Volume1 = ? × r2 × h
Volume1 = ? × 852 × 200
Volume1 = 4539601.384 mm3
Volume2 = ? × r2 × h
Volume2 = ? × 802 × 200
Volume2 = 4021238.597 mm3
Total Volume = Volume1 - Volume2
Total Volume = 518362.7874 mm3
Density = mass / Total Volume
(Also density = 1125 × 10-9 kg/mm3)
Mass = 1125 × 10-9 × 518362.7874
Mass = 0.58316 kg
Mass = 583.16 g
So mass for the two rollers = 1166.32 g
2. Long Shafts (Steel)
The long shafts that are going to be used have the following properties:
Each long shaft has:
Length : 360 mm
Diameter : 15 mm
Density of steel: 7.8 g/cm3
Same method as the previous
Density = mass / Volume
Because shafts are Cylinder then the equation of volume is:
Volume = ? × r2 × h
Volume = ? × 7.52 × 360
Volume = 63617.25 mm3
Then
Mass = density × Volume
(Also density = 7.8 × 10-3 g/mm3)
Mass = 7.8 × 10-3 × 63617.25
Mass = 496.2 g
So, for 2 long shafts mass = 992.43 g
3. Small Shafts (Steel)
The small shafts that are going to be used have the following properties:
Each small shaft has:
Length = 130 mm
Diameter = 15 mm
Density of steel = 7.8 × 10-3 g/mm3
Same method as the previous
Density = mass / Volume
Because shafts are Cylinder then the equation of volume is:
Volume = ? × r2 × h
Volume = ? × 7.52 × 130
Volume = 22972.89628 mm3
Then
Mass = density × Volume
(Also density = 7.8 × 10-3 g/mm3)
Mass = 7.8 × 10-3 × 22972.89628
Mass = 179.189 g
So, for 2 small shafts, mass = 358.38 g
4. Base Plate (Plywood)
The Base Plate that is going to be used has the following properties:
Length : 365 mm
Width : 350 mm
Thickness : 11 mm
Avg Density of plywood: 500 kg/m3
Same method as the previous
Density = mass / Volume
Because the Base Plate is Rectangular then the equation of volume is:
Volume = Length × Width × {Height (in this occasion thickness)}
Volume =365 × 333 × 11
Volume = 1336996 mm3
Then
Mass = density × Volume
(Also density = 0.5 × 10-3 g/mm3)
Mass = 0.5 × 10-3 × 1336996
Mass = 668.5 g
So, the base plate mass = 668.5 g
5. Case Plate (Plywood)
The Case Plate that is going to be used has the following properties:
Length : 225 mm
Width : 343 mm
Thickness : 11 mm
Avg Density of plywood: 500 kg/m3
Same method as the previous
Density = mass / Volume
Because the Base Plate is Rectangular then the equation of volume is:
Volume = Length × Width × {Height (in this occasion thickness)}
Volume =225 × 343 × 11
Volume = 848925 mm3
Then
Mass = density × Volume
(Also density = 0.5 × 10-3 g/mm3)
Mass = 0.5 × 10-3 × 848925
Mass = 424.5 g
So, the case plate mass = 424.5 g
6. Case Supports (Plywood)
The Case Supports that are going to be used have the following properties:
Each Case Support has:
Length : 350 mm
Width : 11 mm
Thickness : 450 mm
Avg Density of plywood: 500 kg/m3
Same method as the previous
Density = mass / Volume
Because the Base Plate is Rectangular then the equation of volume is:
Volume = Length × Width × {Height (in this occasion thickness)}
Volume =350 × 11 × 450
Volume = 1732500 mm3
Then
Mass = density × Volume
(Also density = 0.5 × 10-3 g/mm3)
Mass = 0.5 × 10-3 × 1732500
Mass = 866.25 g
So, for the 2 cases supports, mass = 1732.5 g
7. L-Shape Framework (Aluminium)
The L-Shape Frameworks that are going to be used have the following properties:
Total Values of the beam of the L-Shape:
Length : 4800 mm
Vertical Side : Width: 11 mm, height: 25 mm
Horizontal Side : Width: 22 mm, height: 3 mm
Density of aluminium: 2.70 g/cm3
Same method as the previous
Density = mass / Volume
Because the L-Shape Framework is Rectangular but with a cut of an L - shaped then to find the total volume two equations of volumes are required. Volume3 will be equal as the volume of the L-Shape for the horizontal part and Volume4 will be equal as the volume of the L-shape for the Vertical part. So, the total volume of the L-shape will be the sum of these two volumes.
Volume3 = Length × Width × Height
Volume3 = 4800 × 3 × 25
Volume3 = 360000 mm3
Volume4 = Length × Width × Height
Volume4 = 4800 × 22 × 3
Volume4 = 316800 mm3
Total Volume = Volume3 + Volume4
Total Volume = 1636800 mm3
So,
Mass = density × Total Volume
(Also density = 2.70 × 10-3 g/mm3)
Mass = 2.70 × 10-3 × 1636800
Mass = 1827.36 g
So, the whole mass of the total of the L-shapes = 1827.36 g
8. Back Plate (Plywood)
The Back Plate that is going to be used has the following properties:
Length : 343 mm
Height : 450 mm
Thickness : 11 mm
Avg Density of plywood: 500 kg/m3
Same method as the previous
Density = mass / Volume
Because the Base Plate is Rectangular then the equation of volume is:
Volume = Length × Height × {Width (in this occasion thickness)}
Volume =343 × 450 × 11
Volume = 1697850 mm3
Then
Mass = density × Volume
(Also density = 0.5 × 10-3 g/mm3)
Mass = 0.5 × 10-3 × 1697850
Mass = 848.925 g
So, the back plate has a mass of 848.925 g
Total weight: 9kg aprox
This is under the 15kgs the customer original specified.
Static Failure
The product will under go a series of continuous and non-continuous forces during its life of use. A force is constantly applied by its own mass whilst on earth. It is important that the product is able to support itself and the load of seeds it is carrying when in use. The other key force is the forces created when crushing the seeds between the two rollers. This force acts on the whole in the horizontal direction the applied force puts stress on the shafts, case supports, case panelling and the screws holding it together. If any one of the components fail the product will break.
When Horizontal Force is acting to the Hemp seed press
. Tensile Failure in shafts (steel)
Yield Strength = 250 MPa (stress)
Diameter = 15 mm
Stress = load / Cross-Sectional Area
So, the Area is needed to find the maximum safe load for the shaft until it reaches its yield point.
Area = ? × 7.52
Area = 176.71 mm2
Safe Load = stress × Area
Safe Load = 250 × 106 × 176.71 × 10-6
Safe Load = 44178.6 N
2. Tensile Failure in Case support (plywood)
Yield strength = 13.8 MPa
Thickness = 11 mm
Height = 450 mm
Stress = load / Area
So, the Area is needed to find the maximum safe load for the Case support until it reaches its yield point.
Area = Height × thickness
Area = 450 × 11
Area = 4950 mm2
Safe Load = stress × Area
Safe Load = 13.8 × 106 × 4950 × 10-6
Safe Load = 68310 N
3. Tensile Failure in L-Shape Framework (Aluminium)
Yield strength = 20 MPa
Width = 22 mm
Height = 3mm
Stress = load / area
Safe load = 1320 N
4. Shear Failure in L-Shape
Yield strength 20 MPa
Length = 25 mm
Width = 3 mm
Shear Area = 25 × 3 = 75 mm2
Safe load = 1500 N
When Vertical Load is acting
5. Shear Force of the screws (steel)
So, for Wood screws
Diameter : 5 mm
Length : 20 mm
Shear Area : ? × radius2
Shear stress: 250 MPa
Shear stress = shear Load / shear Area
Safe Load = shear stress × shear Area
Safe Load = 250 × 106 × ? × (2.5 × 10-3)2
Safe Load = 4908.74 N
So Safe Load Calculation for the different plates is:
a. Case Support: Has 11 screws, So Safe Load = 11 × 4908.74
Maximum Safe Load = 53996.14 N
b. Back Plate: Has 12 screws, So Safe Load = 12 × 4908.74
Maximum Safe Load = 58904.88 N
c. Front Plate: Has 7 screws, So Safe Load = 7 × 4908.74
Maximum Safe Load = 34361.18 N
d. Hopper: Has 11 screws, So Safe Load = 11 × 4908.74
Maximum Safe Load = 53996.14 N
e. Middle Part: Has 4 screws, So Safe Load = 4 × 4908.74
Maximum Safe Load = 19634.96 N
6. Compressive failure in Plywood from the screws
Length of screw : 20 mm or 0.02 m
Diameter of the screw : 5 mm or 0.005 m
Shear Stress = 13.8 MPa
Shear Area = 0.02 × 0.005
Shear Area = 10-4
Shear Stress = Load / Shear Area
Safe Load = 13.8× 106 ×10-4
Safe Load = 1380 N
So, for each screw Safe load is 1380 N
7. Shear Force on bearing screws
Length : 35 mm
Diameter : 3 mm
Shear stress: 250 MPa
Shear stress = Load / Shear Area
Safe Load = 1767 N for each screw
So in each bearing house there are 3 screws
So Maximum Safe Load = 3 × 1767
Maximum Safe Load = 5301 N
The calculations show that the design will take the necessary required forces in order to crush the seeds with out any damage to the product.
Testing
Time usage
The four week assembly period suffered set backs due to lack of materials from week one although over all time was used most effectively to work on available parts. The project however has been competed and tested.
Testing procedure
A number of areas of the product need to be tested. This includes its mass, rigidity of the frame, the ability to crush seeds and ease of use. The product is of an adequate size that it can be easily moved by hand onto a set of weighing scales in order to check it's mass. The mass was found to be well with in the required limits.
The rigidity of the structure was tested by simply applying a force to parts of the product and seeing if there was any elastic or plastic deformation or even fracturing. In conclusion the product was found to be a rigid structure able to take the applied forces.
The two rollers.....
Evaluation
Summary of the Evaluation
The product as the weight prediction part in theory was calculated to be 9 kg with extra approximately 2 extra kg because of using Gears and bearing houses the weight was found to be approximately 11 kg. This weight value was achieved by designing the product with lighter materials rather than using stronger and heavier materials.
For the outside of the box Plywood was used, shafts from steel were used to rotate the rollers, rollers from plastic were used and that move diminishes the weight by 2 kg instead of using steel rollers. But in reality the aluminium strips would be replaced with steel ones increasing the weight by and additional 2.7kgs thus bringing the total weight much nearer the specified 15kg max weight. The reason for this is steel is much cheaper and easy to use in the countries this product is likely to be made.
The product is being powered up by manual means. The handle has been inserted into the main steel shaft. When the operator rotates the handle, a gear that has been put inside this main shaft is connected using chains with some other gears which they are connected with the other 3 shafts and by rotating the handle, this gear mechanism rotates the first roller clockwise and the second roller anti-clockwise. This opposite movement maximize the force when the hemp seeds reach the small middle gap between these two rollers making it more efficiently. Also this product is chosen to be powered by manual means because this method uses cheaper materials and not automatic mechanisms that needs time to fix in case they are broken and it is also making this product easier to use by anyone without any help manual and is the best choice to be used in Third World Countries.
The machine was tested with seed nuts which their hardness and size are very similar to the hemp seeds and that was the first big test for this product to watch how every mechanism will react during the crushing. The seed nuts were put on the cone at the top and the gravity pulls the seed nuts into the centre of the gap between the two rollers. The rollers were rotated and the nuts were crushed successfully.
Not Sure. In this first test cake was produced but the efficiency is still unknown.
The total of the value exceed the £60. Although our own production cost was near the specified value, many of our materials are recycled or donated for free. Therefore forma production point of view the estimated cost is nearer £135 brand new, although the design is ideal for production from recycled materials and that cost is easily reduced.
The product is simple to be made and doesn't need any complex design. Also it can be used easily by unskilled people by turning the handle and doesn't need any help manual to learn how to operate it.
The product doesn't need any safety equipment to be used. The operator can use this product by bare hands and without special glasses to protect his eyes. Everything is shaped and closed to avoid any unnecessary safe equipment.
The product is a box that has everything that it needs to work inside of it. Because this product is light and doesn't exceed the 15 kg it is easy to carry it and move it around without using extra personal or additional special equipment.
The product is safe to be used by anyone. Because this product has a simple design and everything that can be considered a threat to the operator is being covered by plywood to protect the operator by accidentally move his hand to the rollers and the edges were filed up to avoid unnecessary injuries and cuts.
The product reaches the British engineering standards by using simple method of design and a variety of hygienic and cheap materials.
The product is hygienic when the cake and oil is being separated. After the hemp seeds will be put into the cone, gravity pulls the hemp seeds into the gap between the two rollers and by crushing cake and oil are produced simultaneously. The cake and oil fall on the first encounter which is perforated box steel. This perforated box is a steel sheet with small holes on it. That allows it to hold the cake and the remaining oil will drop over to a second box which is made by aluminium. After a time period that the seeds will be crushed the cake and the oil will be stored into these two boxes. After the operator is finished these two boxes can be removed and transfer them anywhere. This method of separation is very simple to design and very easy to use it by anyone and everything happens manually which that gives a very hygienic manner in processing the hemp seeds by natural things.
The materials that had been used to produce the product make the product workable at -28 and 44 degrees temperature. Those materials are steel for the shafts and plastic for the rollers that are active during the process. Those materials are invulnerable to this range of temperature.
The materials that had been used (steel, plastic, plywood) are making the product to last more than 5 years with expected service every 2 years
The product has used existing standard parts and tools as possible.
The service time will not exceed the 15 minutes because the hopper can be open up very easily using a mechanism that hold it in place, so the check control of the crushing mechanism can be done very fast and with ease. Also because of the simplicity of the design the damages can be seen by naked eye and the repairs can be done very easily or if a part needs to be replaced should be easy and easy to re-assemble it.
The aesthetics are functional.
The ergonomic ensures comfortable use when in operation
The materials that have been used can withstand corrosion against time. Plywood can stand 5 years , steel, aluminium and plastic that are active during the process are materials that can withstand the corrosion more effectively than other materials and that's the reason that these materials are been placed into these positions where are more important.
The product should be able to withstand 7 hours of work each day for 5 years by using steel, plastic and aluminium as main materials of this product.
References and Figures
Sources
Websites
www.google.co.uk
http://www.nebraskascrewpress.com/oilextraction.html
http://www.rosedowns.co.uk/products/Mini_Press.htm
http://www.fkcscrewpress.com/spintro.html
http://www.gizmology.net/vise.htm
http://www.youtube.com/watch?v=s5H16fQdIkQ
http://www.dakecorp.com/pdf/H-Frame-Section.pdf
http://www.rosedowns.co.uk/brochures/Mini%20Press%20-%20Mini%20040.pdf
http://attra.ncat.org/attra-pub/oilseed.html
http://peacecorps.mtu.edu/resources/studentprojects/TashaDan/Oil_Seed_Processing%20Website.htm
Concept Sketches
Vertical roller press (image 001)
Vertical screw press (image 002)
Conveyer belt press (image 003)
Hydraulic press (Image 004)
Horizontal screw press (image 005)
Images from other sources
Example of petrol driven press. (Photo 1)
Diagram of horizontal screw press workings (Diagram 01)
Photo of a series of hydraulic presses used to crush Hops (Photo 2)
Diagram of the J.P.Paker vertical screw press (Diagram 02)
Mini-press used to crush fruit. (Photo 3)
Photographs during construction
Photo 4, shafts cut to length
Photo 5, rollers assembled
Photo 6, wooden panels and gears cut to size
Photo 7, plastic part for keying the gears being made.
Photo 8, aluminium L-sections cut to length
Photo 9, handle being attached to press and tested
Photo 10, positioning bearing housings for attachment
Photo 11, front view position of draws marked out
Photo 12, positioning the hopper
Photo 13, marking the position of the shaft on the inside panel
Photo 14, dry assembly of hemp press to confirm it will go together
Photo 15, showing position of the shafts and rollers inside the press
Photo16, assembling the front of the press
Photo 17, a bearing housing
Photo 18, assembling the box
Photo 19, attaching the side two the base
Photo 20, attaching aluminium L-sections to front
Photo 21, attaching other side to base
Photo 22, attaching L-sections to base
1 07/02/2012
