Calibration
Part No.: 44200004 - Revision 2
SVP Controller Operation Manual
4-21
Calculation for the Density of the Calibration Water
ρ
wtF = Density of water at temperature t °F (kg/cm) (From API 12.2.4 or
calculate by algorithm taken from API 4.9.4)
Using the algorithm taken from API 4.9.4
ρ
wtF =
ρ
0*[1-((A*
ρ
tF)+(B*(
ρ
tF)^2)-(C*(
ρ
tF)^3)+(D*(
ρ
tF)^4)-(E*
(
ρ
tF)^5)))/1000]
Where:
ρ
wtF is density at temperature t °F (kg/cm)
ρ
0 is density at temperature t0, 999.97358 kg/m3
t is temperature (°F)
∆
tF is [(t – 32)/1.8]- t0
t0 is 3.9818E+00 (°C)
A is 7.0134E-08 (°C)-1
B is 7.926504E-06 (°C)-2
C is -7.575677E-08 (°C)-3
D is 7.314894E-10 (°C)-4
E is -3.596458E-12 (°C)-5
Note:
Above provided equation provide density correlations for density
of distilled water. If the water to be used in the Gravimetric Method
does not meet the criteria of distilled or deionized water, water from
an approved public water (potable) supply may be used in this
procedure. However, the conductivity must not exceed 50μs. If the
conductivity of the test water is between 50μs and 1,000μs, the
density shall be determined as per API 4.9.4 section A.5.
Mw
=
Corrected Mass of Water (gm)
=
Ww ÷ CBW
Vw
=
Volume of Water (cc)
=
Mw ÷
ρ
wtF
CPLp
=
Correction for the effect of pressure on water
=
1/[1 - (Pp * 0.0000032)]
CTSp
=
Correction for effect of temperature on prover
=
{(1+[(Tp-Tb)*Ga])*(1+[(Td-Tb)*Gl ])}
CPSp
=
Correction for effect of pressure
=
1 + ((Pp - Pb) × ID)/(E × WT))
WD
=
Corrected Water Volume
=
(Vw * CTS)/(CPL * CPS)