| 摘要 |
1348540 Spray nozzle; coated electrodes SIEMENS AG 14 May 1971 [15 May 1970] 15101/71 Headings B2E and B2F [Also in Divisions Dl and H1] In the spraying of powder for coating a substrate the powder is, in the embodiment shown in Fig. 6 agitated in a hopper by means of a cam device acting against a movable member 56, falls onto a moving conveyor 66 and is impelled out of an orifice 64 by means of a brush 67, along with air from the interior of the chamber 61 which is kept at above atmospheric pressure. Another embodiment (Fig. 5, not shown) has no chamber 61 and the powder is sprayed by the brush alone, and yet another has the powder fed onto a roller in place of the conveyor 66. The device shown in Fig. 3g is a nozzle consisting of a slit 38 in one cylinder and a helical slit 39 in a cylinder within this, relative rotation of these causing the orifice 33 to move, powder fed to the inside being sprayed from the orifice. The powder sprayed is a catalytic powder of "Raxey" silver or "Raney" nickel optionally mixed with binding agents (or impregnated with them) such as PTFE, polyethylene, or polyglycol, the substrate to be coated either moving in the direction of the spray or against this direction and so a gradation of particles from large to small or vice versa is obtained (see coatings 75 and 76, Fig. 7). Shown are two coatings, 74 and 75 with gauze 77 between them. The coating may be dried and then passed between calendar rolls to consolidate it, and the substrate may be in the form of the individual plates of an electrochemical cell (particularly a fuel cell). Fillers, such as soluble salts (e.g. potassium carbonate or potassium oxalate) may also be added to the powder. |
