Announcement

Collapse
No announcement yet.

Heat ratings

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Heat ratings

    Do anyone know how I can source the maximum heat rating on something?
    Example, the coffee pot at the base of a drop filter machine, I want to know how much heat that can handle ie 225 C for 7 minutes before exploding?
    I recall years ago there used to be those glass vision saucepans that would be ideal but cant seem to source them, failing this im back to a metal one.
    Yes Ive been out in the lab again....

  • #2
    Re: Heat ratings

    Sullo,

    If - and thats a big if - the base is made of genuine pyrex glass (will normally have the word "pyrex" moulded into the base or stencilled on the outside).... it can withstand 230C..... which is pretty close to what you want.... And that is a steady state temperature..... thermal shock (rapid change in temperature) is another consideration - and pyrex also rates well in that category.

    If it is a lesser quality (and it may well be)..... then the maximum temperature is even lower.....

    If in doubt ..... back to metal is safer!

    Comment


    • #3
      Re: Heat ratings

      yeah teh lil pyrex one has it but the one of the coffee pot doesnt have anything?
      I was trying out an idea I had with a variable heat source, air heat witha swirly attachment to make a heat "air path" liked the idea of glass cos it was right size and could see results.
      Probably safer at this stage to use metal, out to the 2 dollar shops!
      It was to be a frankensteins creation iroast clone.
      thanks JavaB

      Comment


      • #4
        Re: Heat ratings

        even easier would be just to buy an iroast but I know I will want to take it apart, so I play now so when I get one I dont do that.....

        Comment


        • #5
          Re: Heat ratings

          Originally posted by Sullo link=1180235682/0#3 date=1180236966
          even easier would be just to buy an iroast but I know I will want to take it apart, so I play now so when I get one I dont do that.....
          Mmmmmm...... maybe you could heavily modify a popcorn popper.... they are similar to an I-Roast.... both being fluid bed roasters...... or have a play with a Corretto.... also a sort of fluid bed and direct heat roaster combined....

          Comment


          • #6
            Re: Heat ratings

            Im trying to avoid dismantling the popper as its in high demand, but I can see having to purchase another one for this experiment.
            Have to do a search on coretto dont know what that is. Also trying toi avoid modifying the bbq, I can get it to the right temperature but once I start it will be relagated to coffee dept, and we kinda like using it to cremate meat at present.
            Decisions decisions....
            Im off to bunnings...

            Comment


            • #7
              Re: Heat ratings

              The Corretto is a heat gun with a bread maker used to agitate the beans... see

              http://coffeesnobs.com.au/YaBB.pl?num=1154442377

              An idea from one of our CS members and it works brilliantly.... some have roasted 1kg with this method.

              Comment


              • #8
                Re: Heat ratings

                I remember seeing pyrex bread tubes attached to poppers with turbocharged fan motors and heating elements. Very tall roasting chamber and highly visible.

                Comment


                • #9
                  Re: Heat ratings

                  Nunu,
                  I very distantly vaguely recall something like that but for the life of me cant remember where or what it was.
                  Turbocharged air, thats the problem Im getting cant get the air movement Im after, temp I can get but only from metal,
                  dont spode you recall what that device was?

                  Many thanks

                  Comment


                  • #10
                    Re: Heat ratings

                    Sullo,

                    Ive seen a similar device..... a tall pyrex tube on top of a super popper (was in America somewhere...... But it still only did a relatively small volume of beans....)

                    The problem is (as I see it) you can get a high volume of air from all sorts of (expensive) fan units.... but getting enough heat into the air to raise it to 250C is almost impossible with electricity as the source..... the airflow from a heatgun is about the most you will get with air hot enough to roast beans using a 2000W electric heater for example.

                    Ive seen a design for one on the internet which used a large gas burner to heat the air.... the designer of this home roaster (which did about a kilo from memory) .... said the cost was many hundreds of US dollars (using second hand parts)- and that is the only design Ive ever found for a "home made" fluid bed roaster.

                    EDIT: as a thought you could check out the gas powered workshop heaters.... they combine a fan which produces quite a volume of air at a high velocity and has an inbuilt gas heater..... kind of like a super heat gun!!

                    Comment


                    • #11
                      Re: Heat ratings

                      Give you guys an idea of my day....
                      I pulled my Konica 7020 photocopier apart in the garage and tried to see how much heat I could get out of the fuser, yes the fuser. (I used to work on copiers as a techie) But realised its not feasable due to small amount i could get thru the heat rollers, another idea using two fusers, which brings power supplies into the problem to rotate a seperate larger heat roller, plus the halogen light tubes would burn out at that heat for that long, scratch that idea. That idea went out the window and the copier still works. I want to build something that has some kind of viewing portal so I can see whats going on, maybe have to have a peekaboo thingy like the has garatis have that little device that sticks in and you pull someout.

                      Why is he doing this I hear you say? Why not and because I can and my parents never let me have a mechano set as a child. Thats why I like working on ATMs well sorta.
                      Somewhere on my way to CS I stumbled across a roasting page and forgot to bookmark it, a guy used gas like you mentioned JavaB which got me thinking of upgrading my bbq and using the burners from the old one, that with the help of my plumbing bro-in-law (for safety, hes certified Im certifiable) and making a rotating drum like Ive seen on here.
                      At the end of the day, I just wanna build it myself, no matter the cost.
                      Weird? yes.

                      But why not eh
                      Thanks for reading and thanks to those that are helping me along the way.
                      Cheers
                      Steve

                      Comment


                      • #12
                        Re: Heat ratings

                        Good luck Steve, I have been trying to build a high capacity fluidised bed roast for some time.

                        I have given up for now and am happily playing with my corretto.

                        I got as far as changing the fan on a heat gun. I used one of the blow up bed inflaters (picture attached). I was aiming for 250 grams though - 1kg would require a heap of air and a heap of heat. I contemplated recycling the air to save heat requirements. This would require either a metal fan or heat exchanger.

                        As for materials I was still playing with metal until I had a design I was happy with. Then I was planning on taking to a scientific glass blower - then use pyrex and someone I met had something made by a guy whilst he was doing a job at uni somewhere. I never got as far as locating an actual blower though. Not much help I guess.

                        Best of luck - love to see what you come up with.

                        Comment


                        • #13
                          Re: Heat ratings

                          Originally posted by wrstikoff link=1180235682/0#11 date=1180277210
                          I got as far as changing the fan on a heat gun. I used one of the blow up bed inflaters (picture attached). I was aiming for 250 grams though - 1kg would require a heap of air and a heap of heat. I contemplated recycling the air to save heat requirements. This would require either a metal fan or heat exchanger.
                          wrstikoff,

                          I had thought of recycling the hot air.... but all commercial and domestic fluid bed roasters vent the air after they have passed it through the beans. You need to get rid of the chaff (Which could be done with a filtering system I guess) and also not recycle the smoke (a much harder problem) or you would have smoky beans which, I would imagine, would taste rather weird in the cup.

                          Thats the biggest limitation I can see - getting enough air to roasting temperature and maintaining it so that the beans are held in the air and roasted..... easy enough with 100-150 grams (popper, I-Roast etc.) but a larger volume becomes almost impossible with a 10A (2400W) domestic mains supply for heating.... gas seems to be the answer.

                          Comment


                          • #14
                            Re: Heat ratings

                            My bro in law has a nissan turbo engine of some sort(hes rebuilding some car) and for some reason grabbed the turbo off me when I was looking at it after he explained how it worked saying no your not attaching it to your coffee roasting thing!
                            I wonder why?
                            Although shortly after he asked is the silvia machine working?

                            Comment


                            • #15
                              Re: Heat ratings

                              [QUOTE=JavaB link=1180235682/0#12 date=1180278545]
                              Originally posted by wrstikoff link=1180235682/0#11 date=1180277210

                              I had thought of recycling the hot air.... but all commercial and domestic fluid bed roasters vent the air after they have passed it through the beans. You need to get rid of the chaff (Which could be done with a filtering system I guess) and also not recycle the smoke (a much harder problem) or you would have smoky beans which, I would imagine, would taste rather weird in the cup.

                              Thats the biggest limitation I can see - getting enough air to roasting temperature and maintaining it so that the beans are held in the air and roasted..... easy enough with 100-150 grams (popper, I-Roast etc.) but a larger volume becomes almost impossible with a 10A (2400W) domestic mains supply for heating.... gas seems to be the answer.
                              JavaB

                              Smokey beans - I understand your point, I was wondering if might just be more like a drum roast?

                              Electric vs gas - A agree, I think maybe 200 to 250 grams would be the limit for a domestic supply. Gas would be perfect, youve got me thinking... :

                              Cheers
                              Dave

                              Comment

                              Working...
                              X