Page 53 - Ciaran Kinsella

Sturdy BioFeeder - Solution Specifications Greywater Harvesting Rotational Moulding Requirements Design Considerations
When designing for rotational molding, the key Maintenance of the greywater harvesting
considerations include material selection, part system was greatly considered when
geometry, and wall thickness. designing the Sturdy BioFeeder.
Filling Heating Cooling Demoulding Common materials like polyethylene and The size of the product is ideal for
polypropylene should be chosen for their maintenance by one person roughly every
flowability and suitability for the process. 2-3 months.
Mould Mould cooled
Mould heated during
dual-axis rotation while still rotating Parts should have uniform wall thickness, ideally The tank has a capacity of roughly 300
between 2-5mm, to ensure strength and material litres, ideal for domestic use such as car
efficiency. Designs should focus on simplicity, as cleaning, gardening and toilet flushing.
complex shapes and sharp corners can lead to
issues with mould filling and part removal.
Commercial Viability Draft angles of 2-3 degrees are necessary for
easy mold extraction, and internal corners should
feature radii to avoid stress concentrations.
Increasing Interest in Sustainable Practices
Less Fertiliser Reliance and Costs Additionally, mould design and cycle time play
significant roles in the process.
Thermoplastic Saves ~€500 a Year Without Water Charges
Powder
Desirability in the Product’s Simplicity Moulds must allow for efficient heat distribution
and cooling, with proper venting to avoid air
Rotational Moulding Process Existing Greywater Products Future Government Regulations / Incentives entrapment.

Design Overview Technical Details
The product is a double walled greywater harvesting
system, that holds nets for different levels of filtration and 661.1 514.7
allows for biological filtration to take place for added B A TRUE R35.0
benefits. It is ideal for domestic applications. R20.0 R10.0 135.0 275.0 R45.0 90.0
70.0
600.0 25.0 475.0 93°
120.0 64.7 150.0
87°
B A R10.0 SECTION A-A SECTION B-B
1448.9 798.9 5.0 SCALE 1 : 15 SCALE 1 : 15
Draft 2deg
Instruction Manual Notes
- System Maintenance - 3 degree draft on all faces (excl. 2 degree draft above)
- Quality of Water - 5mm wall thickness
- Recommendations - Fillet radii of (10-20mm)
- Material: MDPE
Mould Release

Lid Rationale
The lid is moulded seperately. The benefit of the lid is it prevents
the growth of algae, microorganisms and fungi aswell as stopping
insects, animals or debris from contaminating the filtered water.

Filtration Post Processing
The post production process consists of using a hole saw to make three holes in the
marked areas above. This allows for pipes to pass through which then get sealed.
The filtering nets then have to be put into position by threading a nut on the four
Biological corresponding mounting positions.
Sand
Algae Gravel Filtering Nets are bought OTS and cut /
Fungi Charcoal
Micro-organisms custom made (3x Per Tank)
Mould Release