Patent GB-509483-A (GB)
Title: Improvements in rotary dry gas meters
IPC: G01F15/00
Filed: 1937-10-08
Abstract: 509,483. Rotary meters. GEHRE, H. Oct. 8, 1937, Nos. 27414 and 27415. Void. Convention dates, Oct. 8, 1936, and Dec. 29, 1936. [Class 110 (ii)] [Also in Group XXIX] Gas is only allowed to pass through a rotary meter when the consumption is above the minimum quantity which can be measured within the permissible margin of error. Fig. 1 shows a meter 2 having an electrically operated valve 4 in its outlet pipe 3 and driving a sunwheel 7 engaging a planet-wheel 10 which also engages a sun-wheel 8 driven by a constant speed motor 9. On gas being consumed, the initial difference in pressure between the inlet and outlet pipes 1, 3 operates a manometer 15 to close a circuit at the contact 16 to cause a motor or magnet 5 to open the valve 4, The planet-wheel 10 then operates a contact lever 12 through a slipping clutch 11 to engage a contact 13 and complete a second circuit to the motor 5, which second circuit remains closed when the pressure difference between the pipes 1, 3 becomes smaller. If the gas consumption falls to below a rate which can be accurately measured, the circuit is broken by the planet-wheel 10 moving the lever 12 to engage a stop 14 and the valve 4 closes. In a modification, an auxiliary meter measuring accurately a small gas flow is provided, the closure of the valve controlling the flow through the main meter opening the valve allowing gas to flow through the auxiliary meter and viceversa. The operation of the valves is controlled by sun-and-planet gearing and the manometer is dispensed with. A counting mechanism may be operated through summation gearing. Fig. 3 shows an arrangement in which valves 4, 4<1> controlling the outlet from main and auxiliary meters 2, 2<1> are operated by a liquid-sealed bell 25 in a chamber 20. The space below the bell 25 communicates by a pipe 26 with the meter outlet pipe 3 in front of the valve 4 and the space above the bell is connected by a conduit 21 with three-way valves 22, 22<1>. When gas passing through the meter 2<1> exceeds the permissible maximum, the sun-and-planet gearing 7<1>, 81, 10<1> operates the valve 22<1> through a slipping clutch 11<1> to close a conduit 23<1> connected to the pipe 3 and to open a conduit 24<1> allowing gas to escape from the top of the chamber 20 to the atmosphere. The bell 25 consequently rises to open the valve 4 and close the valve 4<1>. When the meter 2<1> stops, the valve 22<1> again closes the conduit 24', but 'the space above the bell remains at atmospheric pressure owing to being connected to a conduit 24 at the valve 22. When the gas passing through the meter 2 is below the permissible minimum the sun-and planet gearing 7, 8, 10 operates the valve 22 to close the conduit 24 and open a conduit 23 leading to the pipe 3; thereby equalizing the pressures above and below the bell 25 and reversing the valves 4, 4<1>. An arrangement is described in which the two valves 22, 22<1> are replaced by a single valve. In other arrangements, the reversal of the valves may be effected hydraulically, electrically, or by the displacement of a float member arranged in the path of the gas against the resistance of a weight or spring. The three-way valve may comprise two drums 45, 45<1>, Fig. 8, formed with apertures 48, 48<1> and secured on a shaft 47 in a chamber 46 containing a sealing liquid. In the position shown, gas can pass from an inlet 50 through the opening 481 to the pipe 491 projecting into the drum 45<1> while the pipe 49 projecting into the drum 45 is sealed. When the drums are turned anti-clockwise, the opening 48<1> is sealed while gas can pass through the opening 48 into the drum 45 and leave by the pipe 49.