Talk:Kingston Hot Press: Process Improvements

From Appropedia
Jump to navigation Jump to search

Hello! I would like to invite everyone to use this discussion page as much as possible as a platform for discussing the Kingston Hot Press and the Waste for Life project.

Yesterday I met with Dr. Matovic at Queen's University. He showed me the prototype Kingston Hot Press and we discussed design challenges. Initially I planned to assist the group with heat transfer issues that were causing non-uniform heating of the forms, however Dr. Matovic has since resolved this problem. A new challenge which has made itself apparent is acheiving relatively productive throughput. At the moment, plastic bags are layered with paper in thin-films. These films are produced on the hot press individually and then shredded. Once a sufficient volume of plastic/paper composite feed is produced, this is then formed into a 24" by 24" by ~1/2" plate in the hotpress. This is very labour intensive, and therefore a separate mechanism for the production of a feed composite would be very desirable.

I am therefore currently investigating the feasibility of designing an extruder to produce feedstock for the hotpress, possibly using a modified meat grinder. First step will be a literature review. I hope to have lots more to show soon! Nate Preston 15:00, 31 March 2010 (UTC)

Just as an update. The scope was modified when further discussion showed it could be beneficial to examine the heat transfer issues more closely to determine if a cheaper solution could be arrived at. Nate Preston 18:42, 26 April 2010 (UTC)

Nate, I have a question about this paragraph: The preliminary heat transfer analysis shows that there is little to no difference between a 1/4" aluminum plate, and a steel plate. Refinement of the model showed that although a 1/2" steel plate improved upon the 1/4" steel plate, the 1/4" aluminum plate provides substantially better temperature consistency then either thickness of steel plate and is the recommended plate design for the Kingston Hot Press. What do you mean by 'no difference....' when you describe the difference in the next sentence?

Thank you for pointing out this unclear sentence. Upon reading it again it does not communicate my point very effectively. By preliminary I mean the initial heat transfer model. The initial heat transfer model (characterized by the initial conditions and boundary conditions I set in the COSMOSWorks platform) did not accurately represent the physical system. This gave some confusing results which suggested the temperature distribution on the bottom plate was almost perfectly even (resulting in almost no temperature gradient) for both an aluminum, and steel plate. Physically, we would expect different results as the conductivity of aluminum is better than steel. By refining the model (with more accurate initial and boundary conditions, I then found more physical results which showed the aluminum plates performed better than the steel plates). I hope this answers your question, please feel free to contact me if you require further clarification. Nate Preston 15:57, 27 April 2010 (UTC)