749 
APPENDIX I 
Use of the UERL Diaphragm Gauge 
by C. R. Niffenegger 
The UERL diaphragm consists of: 
A, The main body of the gauge: The face of the body is a ground sur- 
face which has 8 tapped (1/2 in., N.C. 13-thread) holes equally spaced 
around it. Through the back plate of the gauge are four tapped holes which 
are used to hold the gauge to its support. The number of the gauge is 
stamped on one edge of the face. 
B. The face plate: In the center of the face plate is a circular hole 
(3.432 in, in diameter) with a beveled edge. One side of the face plate is 
a ground surface with 8 holes drilled through ta correspond with the tapped 
holes through the front face of the body. The face plate, also, is numbered 
on one edge. 
C. The diaphragm: There are two thicknesses of diaphragm in use: 14 
gauge (about 0.085 in. thiclmess) and 20 gauge (about 0.038 in. thickness). 
Eight holes are drilled through the plates to correspond with the holes in 
the face plate and the face of the main body of the gauge. The diaphragms 
are numbered according to lot number, sheet number, and individual plate 
number within the sheet. 
D. Twelve bolts (1/2 in. N.C. 13-thread: 1 in. long). Assembling the 
gauge: First of all the inside of the main body, the ground surfaces, and 
the diaphragm must be thoroughly cleaned. The ground surfaces and diaphragm 
should then be checked for burrs. If any are found, be sure to remove them 
as they will allow leakage of water into the gauge. 
A thin layer of Kasson water-proof grease is spread completely over both 
Sides of the diaphragm. This waterproofs the gauge and, also, prevents rust- 
ing of the expesed part of the diaphragm. The diaphragm is then placed be- 
tween the front face ofthe body and the ground surface of the face plate, 
80 the numbers stamped on all three are on the same side of the gauge and so 
the numbered side of the diaphragm is towards to face plate. The bolts are 
then placed in position and all 8 bolts screwed in evenly until the diaphragm 
and face plates are just held in place. (If any of the bolts cannot be 
Screwed in with the fingers, the hole should be tapped out or the bolt re- 
Placed.) They are then tightened with a torque wrench to 35 1b in, The 
gauge is then securely fastened to the support and is ready for use. 
Measuring the diaphragms: Before the gauge is assembled, the thickness 
of each plate must be measured with a micrometer at the three unnumbered 
Sides to get the average thickness. These thiclmesses aré re¢orded. 
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