|
Home
CNR 6167
Journal
CNR Stats
News
Links
E-Mail |
The Signal Foam Meter (manufactured by the Electro-Chemical Engineering Corporation of Chicago), was a device used to control foaming inside the boilers of steam locomotives. This equipment was used extensively on the Western portion of the CNR system, where water conditions contributed to foaming. If the water level inside the boiler becomes excessively high from foaming or from simply pumping in more water then is required, the locomotive may experience priming, which occurs when water enters the dry-pipe and makes its way to the cylinders, which can cause a considerable amount of damage to the machinery.
The device uses a series of electrodes of differing length, located in the boiler and housed in a trough. As the water level in the boiler rises due to foaming or from other causes, water enters this trough and makes contact with the electrodes which opens a valve that release the excess water. The excess water is expelled through a separator mounted in front of the cab, above either the engineer's or fireman's window. A control panel located inside the cab alerts the crew as to when it is in use, and also provides a means of testing the device. When the water level drops, and no longer makes contact with the electrode, the valve closes.
For additional information, look up Patent #1911756 at the United States Patent and Trademark Office.
Unfortunately, very few surviving CNR steam locomotives are equipped with a SFM (although several CPR engines equipped with the SFM are still in existence). Fortunately, CNR 5093 located at Casino Regina in Saskatchewan, is equipped with the SFM, and views of its major components can be seen below.
Wiring to electrodes is visible behind sand dome on engineer's side.
Close-up of wiring to electrode.
View of separator on fireman's side
Close-up of separator. Compare with the separator used with Continuous Blow-Down.
Close-up of control panel in cab.
Photos Courtesy Greg Dureau, Saskatchewan Gaming Commission. |
