Liquid Controls SP2850 (MS-649) - Manual (Page 28)

Sponsler, Inc. Model SP2850-TC with MS649 Page 28 DOC#: MN-2850
CALCULATING EXPANSION COEFFICIENT
Given:
The liquid density is a function of the flowing temperature for many fluids. This unit solves an equation which
represents this physical property of the fluid.
The information which the unit uses to describe the fluid is entered by the user in the following variables:
Reference Temperature, Reference Density, Expansion Coefficient.
This information is available for many fluids in one or more of the following forms:
Fluid Specific Gravity vs. Temp. Table
Specific Gravity vs. Temp. Graph
Fluid Density vs. Temp. Table
Fluid Density vs. Temp. Graph
Begin by obtaining one of the fluid properties for the fluid you are using from available manufacturers information or
Engineering Handbooks. In some cases this information is listed on the Material Safety Datasheet for the fluid.
Two temperature-Density pairs will be required to compute the temperature coefficient.
The reference temperature is simply chosen by the user. Common reference temperatures are 60
°F or 15°C.
However, for cryogenic fluids, the normal boiling point may also be used. In some cases the fluid data may list
properties at 100
°F, this temperature may also be used as the reference temperature.
The reference temperature should be chosen so that it is in the application temperature range. I.e. application
temperature range- 10 to 120
°F, reference temperature of 60°F chosen.
Enter the reference temperature at this point.
The reference density must be represented in terms of mass units desired with respect to the volume units
corresponding to the flowmeter’s K-Factor. I.e. If readout in pounds is desired, and the K-Factor is entered for
pulses/gallon, the density must be entered in units of pounds/gallon.
Equation 1
Density of fluid = (Specific Gravity of fluid) X (Density of Water)
4
Table 1 lists a number of K-Factor/Mass readout units. If your temperature, fluid density or specific gravity is in units
other than those required, you must convert them before entering. Given the Ref. Temp., Ref. Dens., Second
Temp. And Second Dens., calculate the expansion of coefficient as follows:
Equation 2
Expansion Coef.= (Ref. Density - Second Density) / Ref. Density
Secondary Temperature - Ref. Temperature
You are now ready to enter these parameters describing the fluid into the unit.