Fig. 46 illustrates the method of applying auto matic regulators to an oil burning system. The pressure of the steam is regulated by means of a governor that determines the amount of oil and steam fed to the burner. The operation is positive and sim ple. The regulator is set at the desired pressure and connected to the steam line from the boiler; a rise or fall in the steam pressure moves the diaphragm of the regulator, causing the spindle to open or close a valve, and thus regulating the supply of oil or steam to the burner.
Fig. 47 illustrates the method of connecting the Merit automatic fire and draft regulating system to a battery of boilers. A master control used with this system and designed to operate the regulators in ac cordance with load of the boiler.
Oil and steam are both present in the master con trol under pressure. Suppose the fires to be burning up to capacity and the steam gauge just registering maximum pressure. This steam pressure, acting on the master controller, causes it to operate the individ ual regulators which are distributed along the boiler front, one to each burner.
The regulators, acting under this particular influ ence, reduce the supply of oil and steam to the burn ers, diminishing the fires accordingly. At the same instant, both the ash pit and stack dampers are closed proportionately. Should the steam pressure still re main at its maximum, the master controller, after a proper time interval, operates to cause a still further reduction in the fires and drafts through the medium of the individual regulators.
After this final operation the pilot fires are all that remain. The size of this fire has been regulated at the time of installation, so that it is just sufficient to take care of the reduction in each boiler.
To complete the above cycle : As soon as the steam gauge registers a pound drop, or more, if de sired, the master controller reverses its operation and causes all the individual regulators to cut in the "first" fire. Simultaneously, the ash pit and stack dampers are
opened the correct amount.
The size of this "first" fire is determined at the time of installation and is fitted to the particular re quirements. Both steam and oil are regulated to the exact proportion and quantity, and once established these conditions are repeated day after day until other conditions require other settings.
New settings are readily made by simply turning keys in the individual regulators to vary the sizes of the orifices. At the same time the ash pit and stack damper settings are changed correspondingly. Very close adjustment of these can be made as a series of holes are provided in the operating levers by which the throw is changed in very small steps.
If after the "first" fire comes on the steam pressure does not build up, the master controller, after a proper time interval, causes the "second" fire to come on. This operation, like the first, simultaneously admits more oil and steam to the burners and more draft to the ash pit and flues.
This "second" fire may be also adjusted as read ily as the first and its range extends from a fire slightly in excess of the "first" fire up to the capacity of the boilers.
In the above description it was stated that the draft and fires are changed simultaneously. This fea ture we believe is worthy of emphasis, and we are ac cordingly referring to it again.
This desirable feature is secured by having the stems of the valves, which regulate the flow of oil and steam to the burners, prolonged so as to engage the damper levers.