STEAM GAUGE.
A Steam Gauge is an instrument used for indicating in pounds the amount of steam pressure upon each square inch of surface of the boiler. It is very delicately constructed, and should not be tampered with after once being set to indicate correctly. If a steam gauge is found not to indicate the exact pressure in the boiler it should be sent to the factory for repairs. Never attempt to repair it unless all the appliances for so doing are at hand.
A steam gauge should always be placed on a boiler with a syphon, or by tying a knot in the pipe between it and the boiler, so that the steam may condense, thereby allowing the water to operate it. If steam is allowed to enter, the heat would tend to expand the tube in the gauge and it would indicate more than the real pressure.
A steam gauge is usually constructed with a hollow, flat tube, called the Bourdon spring. This tube is bent in a simple curve and fastened at one end, the other end is free and by a simple clock work actuates the pointer which indicates upon the dial the steam pressure per square inch upon the boiler.
Ashcroft Steam Gauge.
Interior
Ashcroft Steam Gauge.
Q. What should be done in case the steam gauge becomes defective?
A. When the steam gauge has become broken by freezing or otherwise, and there is none on hand, the engineer may run by setting the safety valve so that it will blow off within from ten to fifteen pounds less than it is ordinarily set at, and then by careful firing, run until a new gauge can be procured, which should be done without delay.
Some engineers have been known to make a practice of running without a steam gauge.
Q. Would you recommend this method?
A. No, it must be resorted to only in case of a sudden accident and where shutting down would cause great loss. Every engineer should have an extra steam gauge on hand, to be used in case of accident to the one in use.