| 摘要 |
<p>1,143,122. Purging Pitot-tubes. AJEM LABORATORIES Inc. 13 May, 1966 [11 June, 1965], No. 21468/66. Heading F2N. A device for maintaining the accuracy of a Pitot tube and manometer system (not shown), comprises a valve 12 for connecting pressure gas to the static side of the Pitot tube, a valve 14 for connecting pressure gas to the pressure side of the Pitot tube and a valve 10 which can connect, or cut off, valves 12 and 14 to and from a source of pressure-gas supplied through valve 26 or, can open them to atmosphere to exhaust the gas from them, there being means for operating all the valves in a sequence to connect the Pitot tube successively to the supply of gas under pressure, the atmosphere and manometer. The valves 10, 12 and 14 are solenoid operated by means of a switch (Fig. 2, not shown) which causes in sequence:-(A) Valve 10 to close the atmosphere vent and open valves 12 and 14 to gas pressure, the latter valves being closed to the manometer whilst the gas purges the Pitot tubes. (B) Valve 10 closes to pressuregas and opens to atmosphere whilst the valves 12 and 14, set as before, allow the pressure to fall in the Pitot tubes. (C) Valves 12 and 14 now close to atmosphere and open to the manometer so that a reading can be taken. The device is housed in a box which can be de-iced electrically.</p> |
