Post Reply 
(55) Accurate Pressure Measurement
07-05-2020, 12:14 PM
Post: #1
(55) Accurate Pressure Measurement
An extract from An Investigation Into the Required Equipment and Procedures for the Accurate Measurement of Pressure in Hydraulic Fluid Power Systems, The Fluid Power Institute (Milwaukee School of Engineering), AD-A244 165 (U.S.AR. M&E-R&R), May 1976, 139 pgs.
" Snubber Equation Derivation
  Using the laboratory data obtained in Section, characteristic equations for various degrees of snubbing (i.e., 20°, 25°, and 10°), were obtained.
  The P-Q characteristic, in general, for the orifice can be shown to be the following:

  The above equation closely resembles the equation of a straight line:

  A simple least-squares curvefit can now be employed to determine n and log₁₀ K. Actual calculations for these values were performed using HP-55 programmable calculator and the program given below … page 22 Hydlraulic Gauge Capacitance Equation
  It can be shown that the pressure-volume relationship for the bourdon tube pressure gauge is:

  The hydraulic capacitance is defined as the rate of change of volume with respect to pressure. That is,

  Applying the derivative to the original equation gives

  Rearrangement of the above equation results in:

  which resembles the equation of a straight line

  The calculations necessary to obtain the least-square's fit were again performed on a programable HP-55 calculator using the program below … page 22

Find all posts by this user
Quote this message in a reply
Post Reply 

User(s) browsing this thread: 1 Guest(s)