| 摘要 |
<p>942,607. Voltage measuring & testing. BRITISH PETROLEUM CO. Ltd., J.A.CARRUTHERS, and L.J.S.PRINCE. June 29, 1962 [Aug. 16,1961], No. 29544/61. Heading G1U. [Also in Division B1] Apparatus for determining values of electrostatic field strength on a storage tank receiving liquids of low conductivity arising from charges generated by the passage of the liquids comprises a delivery line connected to the storage tank, a bleed line connected to the delivery line, and an electrostatic field strength connected to the discharge of the bleed line, the dimensions of the bleed line and the supply line downstream thereof and the position of the instrument being such that the residence time of liquid in the bleed line from the bleed off point to the position of the instrument is identical with that of the liquid in the delivery line downstream of the bleed point. In Fig.1 a storage vessel (not shown) for a low conductivity liquid e.g. hydrocarbon oil is connected over line 1 and filter 2 to discharge over delivery line 3 into an insulated vessel 4 connected to an earthed electrometer 6 and through a bleed line 7 following the filter into an insulated vessel 8 connected to earthed electrometer 10. The residence time of the liquid in the bleed line is identical with that of the liquid in line 3 downstream of the bleed line, and it is shown that if the electrostatic properties in the bleed line are similar to those of the delivery line the electrostatic currents in the discharge and bleed lines due to the passage of the liquid and the charges on vessels 4, 8 measured by the electrometers are proportional (Figs. 3 to 7 not shown) so that the charge and electrostatic field on vessel 8 measured by electrometer 10 are proportional respectively to those on vessel 5. In Fig. 2 a storage tank 11 is connected by line 12, valve 13, and pump 14 through filter 15 and flow meter 16 to storage tank 17. A bleed following the filter 15 is taken over line 18 to simulation tank 19 whose outlet line 20 is returned to the suction side of the pump and the lines 18, 20 are proportioned to maintain simulation tank 19 just filled. The residence time of the fluid in the bleed line is identical with that in the delivery line. An electric field meter 21 incorporated in the simulation tank generates signals proportional to the electrostatic charge thereon and as shown to that on the receiving storage tank which operate a recorder and an alarm (not shown) responsive to the level of charge on the storage tank due to the passage of the liquid. The signals may also electrically operate valve 13 to control the rate of delivery to maintain the electrostatic discharge on the tank at a predetermined safety level. Constructional dimensions and experimental results are given, and the apparatus is adaptable for use in refilling aircraft or road tankers with petroleum products.</p> |
