Abstract: A method 200 for priming a drainage apparatus 100 comprises directing liquid into the conduit arrangement at 202 via the liquid injection inlet 106b12 to fill up most of the conduit arrangement as controlled by the valves' configuration; directing liquid into the first reservoir 102 at 206 to enable more liquid to enter into the conduit arrangement via the first opening 112 and at 208, to flood the conduit arrangement to form a continuous liquid flow path which extends from the first opening 112 up to at least the second opening 114, the continuous liquid flow path creating a siphon; and with the first opening 112 kept below the liquid's surface level in the first reservoir 102, stopping the flow of liquid into the first reservoir 102 to achieve a state of equilibrium of the siphon at 210 to prime the conduit arrangement.

Abstract: A drainage apparatus (100, 300-800) for siphoning liquid between first and second reservoirs (102, 104) is disclosed. In a first embodiment, the apparatus (100) includes a conduit arrangement having a first opening (112) disposed in the first reservoir (102), a second opening (114) disposed in the second reservoir (104) and a liquid injection inlet (106M2) arranged between the first and second openings (112,114), and a plurality of valves (108, 110) for controlling flow of the liquid along the conduit arrangement.

Abstract: A fluid extraction apparatus comprises a passage 20 for the pumped flow therealong of a first fluid, for example air. A fluid flow area control device in the form of an apertured plug 22 is present in the passage. An inlet 26 to the passage 20 is provided at or downstream of the downstream side of the plug 22. When, in use, the first fluid is pumped along the passage through the aperture 23 of the plug 22 the fluid pressure at the inlet 26 is reduced causing a second fluid to be drawn into the passage 20 via the inlet 26 to flow with the first fluid towards the downstream end of the passage 20. The downstream end of the passage may be provided with a filter 6 in the form of a tank 8 containing an oil dissolving agent 10. The apparatus has a particular application to a cooker hood assembly for extracting a gas from a cooker hood 2, without having to pass the gas through a pump 4, and then treating the extracted gas to remove pollutants such as water, oil droplets and smoke therefrom.