| 摘要 |
<p>1,089,628. Sampling filter for radioactive dust. COMMISSARIAT A L'ENERGIE ATOMIQUE. Nov. 11, 1965 [Nov. 30, 1964], No. 47910/65. Heading B1T. [Also in Division F2] During a period in which air is drawn through a filter 9 by a pump 1 to deposit a sample of air-borne radioactive matter on the filter, the flow rate through the filter is maintained constant in spite of clogging by means of a second filter 6, of sintered bronze, whose resistance to flow is reduced as that of filter 9 rises by reducing the amount of viscous oil which is directed on to filter 6. The oil is contained in annular reservoir 5, subjected through apertures 21 to the pressure in chamber 4 downstream of filter 6, and flows on to disc 6 via conduits 13, 15, auxiliary reservoir 16 and spaced distributors 17 (Fig. 2, not shown). The oil flow is controlled by a valve 14, comprising a mercury-filled tube 18, leading to a closed, air-filled vessel 19, and a ball 20 which floats on the mercury. Clogging of filter 9 reduces the pressure in chamber 4 and this causes ball 20 to rise and close conduit 15, whereby the filter 6 is quickly dried off and its resistance falls to restore equilibrium. A calibrated Pitot tube 24 indicates the air flow, and tube 23 the oil level in reservoir 5.</p> |
