UBUHANZI
UBWIZA N'UBUZIMA
UBUKORIKORI
UMUCO N'AMATEKA
IMYIDAGADURO
IBIDUKIKIJE
IBIRIBWA N'IBINYOBWA
UBWUBATSI BUSUBIRA INYUMA
UBUMENYI
SIPORO
IKORANABUHANGA
IBYAMBARWA
Extruded Polystyrene Foam
Carl Munters had shown that polystyrene heated with methyl chloride under pressure puffs into a closed-cell foam when let out of the vessel (US 2,023,204) - but only in small pieces; with larger outlets the mass collapsed into brittle, irregular lumps. Otis Ray McIntire at Dow found the fix: keep the mass BELOW the critical temperature of methyl chloride, about 143 °C, so the gas stays dissolved, and let its own evaporation cool the foam fast enough to freeze the cells.
**US 2,450,436**, "Manufacture of cellular thermoplastic products", McIntire, assigned to Dow Chemical, filed 26. July 1947, granted 5. October 1948. Its drawing is the pressure vessel with the bottom valve the foam flows out of. Dow sold the result as blue insulation board; the white bead foam of packaging is a later process.
**Methyl chloride is toxic; you start from foam board.** You build a hot-wire cutter, cut an insulated box, and measure how long it keeps ice.
Utangiye
3 hours plus an ice test
Amabwiriza
1
1
The cutter
The cutter
Base on two feet, a post and an arm; the wire runs from the arm tip down through the base to a spring underneath.
2
2
Build the frame
Build the frame
From 18 mm plywood cut a 300 x 300 mm base, two 300 x 40 mm feet, a 280 x 50 mm post and a 200 x 50 mm arm. Glue and screw the post to the back edge and the arm square on top.
Ibikoresho by'iyi ntambwe:
Urupapuro rw'ibiti byometse1 igice
Imisumari y'ibiti10 ibice
Ikinyabutabire cy'Ibiti20 mlIbikoresho bikenewe:
Umucumita w'Intoki
Icyuma Cyivumbura Kidafite Insinga
Ikusanyirizo ry'ibitorezi
Umurongo w'Icyuma3
3
String the wire
String the wire
Drill 2 mm through the arm tip and the base directly below. Fix the wire to an eye bolt on top of the arm, run it down through the base, and tie it to a spring under the base so it stays taut when it expands hot. Check it is square to the table.
Ibikoresho by'iyi ntambwe:
Insinga ya nikorome 80/20 ya mm 0,641 metero
Ibuye rifite ijisho1 igice
Ikusanyirizo ry'imisemburo yikanyiza1 ikirundoIbikoresho bikenewe:
Icyuma Cyivumbura Kidafite Insinga
Ibikoresho by'ibivumbura mu gasanduku4
4
Power it
Power it
Clip leads to the wire at the arm and below the base. Set the bench supply to 1.5 V with a 4 A limit and raise it slowly (notebook) until the wire slides through a scrap cleanly. Ventilate.
Ibikoresho bikenewe:
Isoko ry'Amashanyarazi ry'Ameza Rihindurwa
Alligator to Alligator Cables
Agapfukamunwa N95
Amadarubindi Asobanutse yo Kwirinda5
5
Cut the box
Cut the box
From 25 mm foam board cut a base and lid 200 x 200 mm, two sides 200 x 150 mm and two 150 x 150 mm. Feed slowly - let the wire do the work. Tape the box together.
Ibikoresho by'iyi ntambwe:
Ikibaho cy'urwondo rwa porisitireni rwasunitswe1 urupapuro
Isheme yo gupfundikira1 umuzingoIbikoresho bikenewe:
Umurongo w'Icyuma6
6
Weigh a cube
Weigh a cube
Cut a 50 mm cube from an offcut and weigh it for the notebook.
Ibikoresho bikenewe:
Iminzani ya Digitale yo mu Gikoni7
7
The ice test
The ice test
Put 500 g of ice in a bag in the foam box and another 500 g in a cardboard box of the same size, side by side in the same room. Note the room temperature and check both every hour until the ice is gone.
Ibikoresho by'iyi ntambwe:
Utubuye tw'urubura1000 g
Agasanduku ka karito ifite imikondo1 igiceIbikoresho bikenewe:
Iminzani ya Digitale yo mu Gikoni
Igipimo cy'ubushyuhe cy'icyumba8
8
Wire, density, heat leak
Wire, density, heat leak
Gupakira ikaye ya Jupyter…
9
9
History & Context
History & Context
**What the patent specifies:** polystyrene with methyl chloride dissolved under pressure below the gas's critical temperature, released through an outlet so evaporation expands and cools it into uniform closed cells, in blocks 2 inches thick or more. **Modern build (derived):** commercial extruded foam board, today made with other blowing agents.
The patent names its target plainly: blocks big enough to cut into insulating panels for refrigerators. Its limits: it melts at low heat, burns unless treated, dissolves in many solvents (and in some glues and paints), and breaks down in sunlight.
Ibikoresho
10- 1 igiceUmwanya
- 10 ibiceUmwanya
- Umwanya
- Umwanya
- 1 igiceUmwanya
- 1 ikirundoUmwanya
- Umwanya
- 1 umuzingoUmwanya
- 1000 gUmwanya
- Umwanya
Ibikoresho bikenewe
11- Umwanya
- 1 vendor sell this, none ship to you yetUmwanya
- Umwanya
- Umwanya
- Alligator to Alligator Cables10% komisiyo$3.58
- Umwanya
Dosiye z'igishushanyo
1Blueprint zijyanye
Izi blueprint zisangira ubumenyi — uburyo, ibikoresho cyangwa amahame
CC0 Umurenge rusange
Iyi blueprint yasohowe munsi ya CC0. Ushobora gukoporora, guhindura, gukwirakwiza no gukoresha nta kwemererwa.
Shyigikira Umuremyi ugura ibicuruzwa binyuze muri Blueprint ye Komisiyo y'Umuremyi byashyizweho n'Abacuruzi, cyangwa kora verisiyo nshya y'iyi Blueprint ukayinjiza nk'isano muri Blueprint yawe kugira ngo musangire inyungu.