TB 9-6685-319-35
(14) Slowly open shutoff valve on pneumatic pressure controller.
(15) Increase pneumatic pressure, using metering valve on pneumatic pressure
controller until weight rises approximately 9/16-inch above the deadweight cylinder
NOTE
Making all pressure changes (however large or small) with
pneumatic pressure controller. Vernier pressure changes can
be made using screw-type pump on pneumatic pressure
controller. The hydraulic hand pump should not be used after
initial diaphragm positioning in (6) and (7) above.
(16) After reading and recording TI indication, a correction must be applied to each
indication. The difference between reference plane of fluid separator (B8) and deadweight
tester when both are resting on same table is 0.988-inch for high range position and 3.578-
inches for low range position. The density of recommended oil (MIL-L-7870A) is 0.8653
gm/cc at 23 gm/cc at 230C; therefore, 1-inch of this oil produces a pressure of 0.03125 psi.
Thus, 0.031 psi (0.0312 psi x 0.98 inch) for high range position and 0.112 psi (0.3125 psi x
3.578 inch) for low range position must be subtracted from each TI indication.
(17) If TI indication after correction does not indicate within limits calculated in (2)
above, perform b below.
(18) Close inlet valve and slowly open exhaust valve.
(19) Release pressure by opening metering valve.
(20) Repeat (2) and (12) through (19) above, using enough weights to obtain cardinal
points nearest to 80, 60, 40, and 20 percent of TI scale. Pressure changes can be made by
proper use of inlet, exhaust, metering, and shutoff valves.
b. Adjustments. Perform 8b above.
16. 1000 to 5000 Psi Pneumatic Gages (0.1 to 1 Percent Accuracy)
WARNING
To prevent injury to personnel or damage to equipment, make
certain that all components used are clean and have not been
contaminated with oil or grease.
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