Patent GB-787530-A (GB)
Title: Improvements in liquid tanks or reservoirs
IPC: F16L27/08
Filed: 1955-10-25
Abstract: 787,530. Gravity-separation apparatus. MULLER, J. Oct. 25, 1955 [Feb. 16, 1954 ; Dec. 12, 1955], No. 30522/55. Class 46. [Also in Group XVII] A tank construction in which the main supply and withdrawal pipe is automatically closed when the tank is full and in which said pipe is also closed when the tank has been emptied to a level at which settled impurities or denser liquids may commence to be withdrawn comprises a pivoted extension of said pipe in the form of a floating arm following the variation of the liquid level in the tank, and a cut off device in the pipe or its extension that is closed when the floating arm is at its permitted upper or lower positions. Fig 9. The floating arm 15 is coupled to a sliding piston 63 in an extension 102 of the main pipe 14. The piston 63 is by-passed by a side passage 105 that is closed whenever the floating arm 15 causes the piston 63 to rise or fall sufficiently. When the tank is being emptied via the arm 15 and pipe 14, the piston 63 descends until it closes the lower end of the passage 105 to prevent further withdrawal of the 'liquid. Since this position of the piston 63 also prevents the tank from being filled a valve 60 is provided in the extension 102 that opens under the pressure of any liquid entering by the pipe 14. The resulting rise in liquid level in the tank then causes the piston 63 to rise and open the side passage 105. When the tank is full the piston 63 is in an upper position closing both the passage 105 and the opening to the valve 60 to stop the liquid supply. To enable liquid to be extracted under these conditions a suction valve 80 is incorporated in the piston 63 that opens when suction is applied to the pipe 14 for the purpose of withdrawing liquid from the tank. Fig. 4. In this construction the floating arm 15 has an extension 48 supported by a pair of pivoted floats 16. A cut off piston 63, in the extension 48 is by-passed by passage 56. The piston 63 is connected by rods 66 to two control levers 71 and 77, one lever 71 extending downwardly and the other lever 77 extending upwardly both levers being adapted to move the piston 63 in a closing sense when they abut respectively against the lower wall and against the upper wall of the tank as a result of a sufficient rise or fall of the arm 15. When the cut off piston has been caused to close the bypass passage 56 because the arm 15 has descended to its lowermost position any liquid fed into the pipe 14 and arm 15 causes a valve 60 to open under liquid pressure. As the arm 15 is caused to rise to its highest permitted position a plate 78 on the lever 77 presses against the valve 60 to close it and as the lever 77 presses against the upper wall 1B of the tank the piston 63 is caused to close the arm 15 and the liquid supply is thus cut off. A suction valve 18 is included in the piston 63 for the purpose described with reference to Fig. 9.  Fig. 13. In this construction the arm 15 is encased in floatable material 121 and it includes two valves 122 and 123 normally biased to an open position by springs 124 and 125, each valve being coupled to a control lever 131 and 133 serving the same purpose as the levers 71 and 77 in Fig. 4. Thus when the arm has descended such that the lever 131 touches the bottom 1A of the tank the valve 122 is caused to close to prevent further emptying. A pressure release valve 132 in the valve 122 however permits filling of the tank. The suction valve 134 in the valve 123 permits emptying of the tank when the valve 122 is closed because the tank is full. Fig. 15. This construction is similar to that described with reference to Fig. 13 but to ensure complete filling of the tank I when floats 16 are used the arm 15 has an extra port 135 permitting entry of liquid into the tank, this port being closed by a valve and link mechanism only when a float 147 coupled thereto and projecting into a dome 148 floats on the rising liquid level. Fig. 18. In this construction a float 169 is adapted to close a valve 159 in the pipe 14, both for withdrawal and filling, if any water at the bottom of the tank rises above a level 171, the level being just below that at which the lever 131 causes the piston in the pipe 15 to close. The water may be extracted through a pipe 170. Alternatively an addition float may be coupled to the free end of the arm 15, the float being such that it is not biased upwardly by the normal liquid in the tank but if it is contacted by any lower water layer it is buoyed up to cause a valve in the arm 15 to close. Turbulence. The free end of the arm 15 may be fitted with means for limiting the turbulence set up by liquids fed into the tank. Indicating means. The tank may be fitted with means coupled to the arm 15 for indicating the level of the liquids in the tank. Similarly, means may be coupled to the floats 169, Fig. 18, for indicating the depth of any water in the fuel supply tank. Floats. There are preferably two floats 16, spaced one on each side of the arm 15, the arm 15 terminating in a T junction and the floats 16 being pivoted on an axis parallel with the head of the T.