Powder dosing apparatus

Powder dosing apparatus comprising:

• (a) a first, horizontal, tray for containing said powder in the form of a continuous layer of substantially uniform pre-determined thickness;
• (b) support means adjacent to said tray for horizontally supporting a second tray containing an array of receptacles in which the powder is to be dosed;
• (c) dosing means supported generally above the level of the first tray and the support means and comprising a corresponding array of vertically disposed tubular members open at their respective lower ends and each having a piston slidably mounted therein, the dosing means being movable alternately between a first position above the first tray and a second position above the second tray, in which second position the open ends of the tubular members are in register with the receptacles;
• (d) means to lower and to raise the tubular members when the dosing means is in its first position into and out of the first tray wherby part of the bore of each tubular member becomes filled with, and extracts from, the powder layer, a slug of a predetermined quantity of the powder;
• (e) means to lower the piston within each tubular member, when the dosing means is in its second position, so as to eject each slug of powder into the receptacle below it;
• (f) means for moving the second tray from the support means after the receptacles thereon have received the slugs of powder;
• (g) means for successively feeding further second trays and receptacles onto the support means for receiving, in turn, slugs of powder, and;
• (h) feed means, rake means and levelling means operative, when the dosing means is in its second position, to feed power onto the first tray and to rake and level the powder, respectively, so as to ensure that, in advance of each slug extraction step, the layer is continuous and of said substantially uniform predetermined thickness.