This section is from the book "The Principles And Practice Of Modern House-Construction", by G. Lister Sutcliffe. Also available from Amazon: How Your House Works: A Visual Guide to Understanding & Maintaining Your Home.
Fig. 642. - Connection of Internal Gas main to Dry Meter.
The taps to gas-fittings and supply-pipes are usually of the plain plug type, having a hole straight through the plug, a quarter-turn either way turning the gas on or off. In some fittings, such as hall-lamps, the plugs of the taps have only one hole in the side communicating with the interior of the hollow plug, and a quarter-turn serves to turn it on or off, but the plug must be turned backwards and forwards through the same quarter space, instead of the two half spaces in the taps of chandeliers, brackets, and pendants. Main gas-taps for lead or iron pipes are plug taps of the ordinary kind, having a quarter-turn.
Gas-governors are fittings arranged to open and close the gas-tap on the main supply according to the number of lights in use. The face of the indicator may be arranged for any number of lights, and by turning the pointer to the number of lights in use, the gas-tap is opened or closed to correspond, thus allowing only the amount of gas consumed by the number of lights in use to pass through the meter. The great advantage of an arrangement of this kind is that, no matter how high the pressure may be in the street-main, it is completely broken up when the governor is properly regulated, and no loss is caused to the consumer by excessive pressure. It is useless to try and regulate the gas-tap without an automatic arrangement of this kind, for the regulation of the tap must be in proportion to the number of lights in use, and must be altered as lights are added or put out These regulators may be fixed in any convenient position.
Bruce. Peebles, & Co.'s mercurial gas-governor for mains (Fig. 643) is not so complicated in its parts as most others. There is no possibility of water lodging in it in such a way as to interfere with its working. It is claimed for this governor that it comes into action at a lower pressure than most others, and as all governors supplied are tested before leaving the works, they will be properly regulated. It may, however, be pointed out that the weighting arrangements are not as sensitive as they might be, and to regulate the bell by means of these weights requires much more patience and skill than the ordinary gas-fitter is likely to possess. In the "Wenham" gas-governor (Fig. 644) the difference in the weighting arrangements will be at once apparent. The principle of the governor is the same, including a bell, mercury seal, and two valves, instead of the one in the former. In addition to the improved weighting arrangements (which consist of a & Co's, Marcurial Gas -governor lever with movable weight and screw), the interior of the governor is arranged to prevent it opening and closing too rapidly. In use this governor will be
Fig. 644. - Section of the Wenham Gas grvernor.
Fig. 645 - Section of the stott Gas governor much more steady in operation, and can always be relied upon to correct the flow of gas without causing the lights to fluctuate.
The "Shaw" gas-governor is in principle the same as the "Wenham", with the exception of the weighting arrangements. There is little difference between the "Stott" and the "Shaw" gas-governors. In principle and weighting they are alike. In construction they differ slightly, the ways in the "Stott" (Fig. 645) being larger and clearer than in the "Shaw" (Fig. 646). The construction of the "Shaw" allows it be taken to pieces and cleaned much more readily than the "Stott". In regard to actual gas-governing capabilities, they may be set down as exactly alike, there being no difference in principle or weighting; but when compared with the "Wenham", both the "Stott" and the'"Shaw" fail. owing to the faulty system of applying the weights.
Fig. 646.-Section of the Shaw Gas-governor.
The ••needle" governor burner (Fig. 647) is a gas-burner constructed to pass a given quantity of gas, and to thoroughly break up the pressure, thus maintaining an uniform consumption under varying pressures. These burners effect a considerable saving of gas, and it is impossible to have a smoky flame, as the whole of the gas is consumed, and the maximum amount of illumination (with an open-flame burner) is therefore attained. The "automatic" governor (Fig. 648), made by the same firm, is designed to control the quantity of gas supplied to gas-fires and stoves. By means of the regulating screw underneath, the quantity of gas delivered can be easily adjusted to suit the capacity of the stove or fire. It is a simple and efficient governor.
By-pass taps are used for keeping small jets continually burning in such positions that the whole of the lights in connection with them will be properly lit by simply turning the gas on to the full. They are also used in churches and theatre-, where the lights are often turned down to prevent overheating as well as unnecessary consumption. By-pass taps may be regulated to give a mere glimmer of light or up to a quarter of the full supply. Small by-pass taps are necessary where the fittings are in such positions as to be practically inaccessible for lighting by hand, and in many places they save a large amount of time, as all that is necessary where they are provided is to turn on the supply.
The connection of gas-pipes to fittings, including stoves, gas-fires, and cooking-ranges, should be by brass unions. In some cases the unions will form part of the gas-taps, and in others they will be complete in themselves. The unions should be those known as ground unions, requiring no packing materials. They should also be used when connecting pipes of different metals, such as iron to lead, and lead to copper.
Blocks or pateras are used for the purpose of fixing brackets and pendants. The block is secured to a fixing in the wall or ceiling, and the fitting is afterwards secured to the block. In the commoner class of fittings the blocks are from 4 to 8 inches in diameter, and ¾ to 1 inch thick, the edge moulded or carved. In the better class of fittings the blocks must be made to match the
Fig. 647- section of Brauce. peebles & Co's Needle GovernorBurner.
Fig. 648 - Bruce, Peebles, A Co's "Automatic" Gas-governor for Stores and Fires back of the fitting, the shapes of which have been considerably improved during recent years.