Patent GB-229683-A (GB)
Title: An improved method of and apparatus for controlling valves or equivalents in gas supply systems
IPC: F16K21/16
Filed: 1925-02-19
Abstract: 229,683. Dozy, J. Feb. 19, 1925. Ball and float valves; valves actuated by vessels receiving and discharging liquids.-A valve device for use on gas pipes is arranged so that a large permanent alteration of pressure on the delivery side causes an almost closed condition whilst a temporary depression secures gas supply at least during a certain period. In the form shown in the Figure the valve 7 is connected to a lever pivoted at 9 and provided with an open vessel 8 so that the valve is opened when the vessel is filled with liquid. The vessel 8 is arranged in a closed tank 4 connected by a pipe 15 with the discharge side of the main conduit and separated by a ported partition 5 from a similar tank 3 connected by a pipe 14 with the inlet side of the main valve. The lever 6 which is loaded by a weight 18 is provided with a dash-pot 27 and has supplementary hand-actuating means 19. The bottom of the vessel 8 has two adjustable orifices 10, 24, the first discharging into the tank while the second discharges through an hollow arm 25 having an aperture 26 into the tank 3. The inlet and outlet side are connected by a bye-pass passage 12 controlled by a manually adjusted valve 13 and a valve 30 actuated by a vessel 21 having an outlet aperture 22. On opening a valve on the conduit 2 the liquid level rises in the tank 4 and floods the vessel 8. When the outlet. valve is closed the levels in the two tanks equalize and the vessel 8 sinks and opens the valve 7. If the orifice 10 is open the vessel 8 gradually discharges and allows the valve 7 to close; if on the other hand the orifice 24 alone is open and the valve on the conduit 2 is reopened a certain amount of liquid corresponding to the drop in pressure across the valve 7 is retained in the vessel 8 and the level in the tank 4 stands at a higher point than that in the tank 3; this it is stated allows the valve 7 to remain open just enough to supply the required amount of gas to the conduit 2. To obtain a large supply from the conduit 2 it is necessary to open a second valve on the conduit 2 twice in succession. In this event the dashpot 27 holds the valve 7 in succession open while the vessel 8 is being refilled and then partly emptied. In a modification a float-operated friction brake is used to hold the valve 7 open during this operation. In a further modification a temporary supply of gas is obtained by mounting a valve on a float which, is flooded when the outlet valve is opened. A float connected to the valve may also be arranged in a tank similar to the tank 4, a leaky non-return valve being fitted in the passage connecting the two tanks. In the form shown in Fig. 5, the two tanks 44, 45 open to the inlet and outlet conduits respectively and are connected through an adjustable orifice 47 and also through a non-return valve 46. The main valve 51 is carried by a float 50 working in the tank 44, and the compartment 45 is provided with an adjustable displacer 49 to vary the rise of level obtained on reduction of pressure. When the outlet pressure is reduced the level falls in the tank 44, but the valve is held to its seat by the inlet pressure until the inlet and outlet pressures are equalized. In a modification of this form the valve is slidably connected to the float spindle and the two tanks are arranged concentrically. In another arrangement using concentric tanks a vessel suspended from the valve member is adapted to be flooded by the use of level consequent in the fall of outlet pressure.