BS 4591:1990 pdf free.Method for Determination ofdistillation characteristics of organic liquids (otherthan petroleum products).
BS 4591 In each of the four sides of the draught screen arethree air-vent holes with their centre 25 mm abovethe base of the draught screen.These holes occupythe positions shown in Figure 5,the diameter of theholes situated centrally in the wider side being 25 mm, and the diameter of theremaining 10 holes 12,5 mm.
At the middle of each of the wider sides, a verticalslot for the side tube of the distillation flask, dimensioned as shown in Figure 5, is cut downwards from the top of the screen. A removableshutter, conforming to the dimensions in Figure 5, isprovided for closing whichever vertical slot is not inuse.
A shelf of hard heat-resistant board 6 mm inthickness and possessing a centrally cut circularhole 110 mm in diameter, is supported horizontallyin the screen and fits closely to the sides of thescreen, to ensure that hot gases from the source ofheat do not come into contact with the sides or neckof the flask.The supports for shelf may consist oftriangular pieces of metal sheet firmly fixed to thescreen at its four corners.
In one of the narrower sides of the screen, a door isprovided having the dimensions shown in Figure 5and overlapping an opening in the screen by approximately 5 mm all round.
In each of the narrower sides of the screen, a micawindow is placed centrally with the bottom of thewindow level with the top of the heat-resistant shelf.The dimensions and the positions of the windowsare shown in Figure 5.
The heat-resistant board (5.1.6) shall be placed onthe top of the heat-resistant shelf of the draughtscreen so that the two holes are approximatelyconcentric.The flask is then placed in position so asto close the hole in the heat resistant board completely.
The flask shall be connected to the condenser so thatthe end of the side tube projects at least 25 mm intothe condenser and is coaxial with it.BS 4591 pdf download.