Permission for comments and photos to be printed granted by the Heise Bourdon Tube Company
'In this day of 2400-pound steam for central station turbo-generators, and 25,000-pound and more psi in hydraulic mechanisms having to do with missiles and various other fields and laboratories, the need arises for new types of pressure gages some of which may ordinarily not even be recognized as such.
But in the Bourdon tube category, we find that, as pressures climb, the tubes become more and more circular in cross-section, since the oval or flattened style tube would be subject to splitting. As the tubes approach the circular cross-section in geometry, they do of course become less sensitive. But this factor is compensated by making several turns or loops in the tube, much like a coiled-up garden hose. This is a unique way in which to derive strain-multiplication.
In the accompanying photographs of the tube and complete (50,000 psi) gage as manufactured in this country by the Heise Bourdon Tube Company, it is seen that there are two and three-quarters turns in the rounded tube. Even again as remarkable is the fact that these particular gages carry a gauranted accuracy of one-tenth of one percent of full scale pressure at any point of the dial! A similar gage built by this manufacturer, calibrated to 100,000 psi and having a 16-inch face cost just beyond four hundred dollars. Need a couple for the old boiler?'
Courtesy of Ted Nicolls, 1455 Lochbrea Road, Apt, 19, Sacramento 15, California