GB315030A - Improvements in or relating to gas or other fluid meters - Google Patents

Abstract

315,030. Jackson, L. Mellersh-, (Connersville BlowerCo.). April 21, 1928. Counters actuated by revolving mechanism; counters affording several rates of actuation; counting apparatus with variable-step movement. - In a gas or liquid meter of the positive displacement type comprising a casing containing two rotating inter-related lobed elements geared together, the registering or recording mechanism is advanced to compensate for the slippage " of the gas or liquid through the clearance spaces of the meter by means controlled by the rate of flow of the gas or liquid. The gas or liquid, when the flow falls below a predetermined rate, may be caused to pass through a small meter which is geared to the registering mechanism of the main meter in such a manner that the registering mechanism is driven by the faster moving meter. Fig. 1 shows a positive displacement meter 10 in the inlet chamber 31 of which is fitted a valve plate 30 operated through a linkage 33 from a diaphragm 34 subjected on its lower side to the .meter inlet pressure and on its upper side to the meter outlet pressure. During normal working all the gas passes through ports 21 directly to the meter, but when the demand is small the diaphragm 34 operates the valve 30 to close the ports 21 and to open a port 22 thereby causing the gas to pass through a diaphragm meter 26 before passing through the meter 10. The registering mechanism 15 is driven from the shafts 14, 40 of the main and small meters 10, 26 respectively by means of the gearing shown in Fig. 2, including pawls and ratchets 48, 49, and 57, 56 which cause the faster moving meter only to be operative. The shaft 14 of the main meter drives the pawl and ratchet gearing 48, 49 through differential gearing D comprising a central body 60 carrying idler pinions 61 connecting pinions 62 mounted on shafts 43, 44. The body 60 is provided with worm teeth 63 engaged by a worm 64 operated through pawl and ratchet gearing 70, 69 by a gear wheel 42 on the shaft 43. The increased movement of the shaft caused by the differential gearing D is varied to compensate for the variations in the slippage by a masking member 80 which is arranged under the pawl 70 and is operated from the linkage 33 through a link 82. In a modified apparatus, a pivoted flap valve arranged in the gas inlet pipe to the main meter 10 to cause the gas to pass through the meter 26 when the demand is small is raised by the gas flow as the demand increases, the masking members 80 being either operated by the flap valve or by a centrifugal governor driven by the meter 10. In another modification the differential gearing is operated by pawl and ratchet gearing in which the travel of the pawl is varied to compensate for the slippage and in a further modification the differential gearing is dispensed with and the main meter drives the registering mechanism through pawl and ratchet gearing fitted with a masking member operated as previously described.