278 MODERN GASWORKS PRACTICE
and Cowan’s system, is illustrated in Fig. 197. The passage of the gas along the foul main is governed by the sliding reel which. depends.from the centre of the governor bell. At the same time communication between the holder and the main on the
In/et
Fig. 198.—Bbaddock’s Rbtobt-House Governor.
governors in relation to the size of
retort-ben ch side is effected by the service pipe shown. By means of the weights the bell is so poised that the desired vacuum is obtained. Should the gas coming from the retort bench increase in volume, then the vacuum in the foul main will decrease, with the result that there is less “ sucking-down ” on the bell, which accordingly rises. This movement raises the reel and opens the gas-way until the previous conditions of vacuum are regained, and vice, versa. This type of regulation, with the open reel, is to be pre-ferred to those governors in which the gas in its tarry condition. is forced to travel through narrow slots. These slots lend themselves to blockage, particularly when a system of dry mains is in use. It is as well to arrange for a thin layer of oil on the surface of the holder water.
Another type of retort-house governor, in which the principle is essentially the same as the foregoing, is illustrated. in Fig. 198. It will be noted, however, that the valve is constructed differently from that shown in Fig. 197. The following table shows the capacity of retort-house their connections:—
Diameter of Inlet and Outlet. Nominal Capacity per 24 Hours.
Inehes. 6 8 10 Cubic Feet. 300,000 500,000 750,000 1,250,000
14 15 16 18' 1,500,000 1,750,000 2,000,000 2,500,000