Anglicky v odborných předmětech "Support of teaching technical subjects in English “

1. Anglicky v odborných předmětech"Support ofteachingtechnicalsubjects in English“ Tutorial: Engineeringtechnology Topic: Flame welding Prepared by : Ing. Josef Martinák st. Projekt Anglicky v odborných předmětech, CZ.1.07/1.3.09/04.0002 je spolufinancován Evropským sociálním fondem a státním rozpočtem České republiky.

2. Flame welding – equipment(set) Cap-Nut Oxygen valve Reduction valve handle Fitting with valves Welding wire Identifying oxygen colors – white and blue Valves against backward flashing Acetylene valve Mixing pipe Colourful acetylene labelling – chesnut brown (SRN), white (ČR) weldment Burner nozzle Labeling N – new colorfullabeling in SRN valid from 1st July 2006 Pressure jet Flammable gas Gas inputs Pressure bottles Mixing jet oxygen

3. Gases for welding and oxygen cutting • Oxygen O2 – without colour, taste, smell, non-toxic, encourages burning • Acetylene C2H2 – flammable, high heating value, it explodes with oxygen • Hydrogen H2 – colourless, nontoxic, it makes explosive mixture with oxygen • Propane, butane – nontoxic, it makes explosive mixture with air and oxygen

4. Bottleforgases – bottlevalve Upper spindle nut spring Manual wheel Upper spindle Valve nut Fibre ring Sleeve top Valve unit Bottom spindle Fibre fitting Cone of hard rubber Connection to reduction valve Socket ring bottle gas Bottle neck

5. Acetylene bottle Reduction valve White painting Porous mass acetone 2 Acetylene bottle

6. Reduction valves Inside gauge Safety valve Bottle cap To burner Gas shut-off Pressure bottle Regulation pressure bolt Outside gauge

7. Reductionvalves – oxygen - acetylene • Oxygen pressure – we set it at closed valve • Working pressure for welding is 0,3 – 0,4 MPa • Acetylene pressure – we set it at closed burner valve – probably 30 – 40 kPa • Working pressure can not be increased over 0,15 MPa • Ignition temperature is about 335°C • Safety valve – protects reduction valve against high pressure • Protection against burning – there is net of copper wire between bottle valve and reduction valve, it must be near oxygen For oxygen For acetylene

8. Welding burners • Low-pressure (injector) • High-pressure (mixing) injector oxygen Mixing chamber oxygen acetylene acetylene

9. Welding flames • Neutral flame – ratio of oxygen to acetylene is 1:1 • Welding cone is white, usage – steel, copper, zinc, lead, some kinds of bronze Welding cone nosepipe Welding material

10. Reduction flame – acetylene surplus • Weld is brittle and hard • Aluminium, cast iron and magnesium welding Acetylene surplus

11. Oxidizing flame – oxygen surplus • Suitable for brass welding, some kinds of bronze, for surface steel hardening by flame Bluish shortened welding cone

12. Questions and revision • What materials do we weld using neutral flame?

13. Literarure • DILLINGER, Josef. A KOL. Moderní strojírenství pro školu i praxi. 1. Praha: Europa-Sobotáles, 2007. ISBN 978-80-86706-19-1. • M. HLUCHÝ, J. KOLOUCH, R. PAŇÁK. Strojírenská technologie II Translation: • www.seznam.cz • www.slovnik.cz • JANATA, Petr. Handy slovník technický anglicko-český a česko-anglický. Plzeň: Nakladatelství Fraus, 2000. ISBN 80-7238-075-3 • Lingea LEXIKON 5, Technický slovník anglicko-český a česko-anglický. 2010.