Tabla de contenido
Publicidad
Determining Compressibility Factors
Editing a Method
Use the following procedure to calculate the compressibility factor for
solvents not listed in the solvent library. In general, the more
compressible the solvent, the higher the compressibility factor needs to
be, for example water is 100, heptane is 200.
1. Select H2O as solvent (compressibility factor set to 100)
2. Run the pump at the expected flow rate (set point flow rate) and back
pressure with the solvent (or solvent mixture). The back pressure
should be within ± 50% of the pressure at which the pump will
normally operate.
3. Measure the flow rate using a stop watch and volumetric flask or
pipette. Measurement time should be more than 90 seconds to
ensure accuracy.
Calculate solvent compressibility; C, using:
C = ((Set point flow rate)/(Measured flow rate))(A/ (B+P ))
A = 0.137, B = 43,450, P = operating pressure in psi
Calculate the compressibility factor; CF, using:
CF = 100 + (C-.00000301)/.0000000596
Pressing Edit displays four options which can be selected by using the
and
keys. Refer to Figure 8.
To Modify or Build a New Method
1. Press Edit.
2. Enter the number of the method to be edited, press Enter.
Alternatively, the
number.
3. Press the
or
keys to get to the parameter that needs to be
edited.
4. Enter a new value, press Enter.
To Copy a Method
1. Press Edit.
2. Press the
key once to get to the Copy Method field.
3. Enter the number of the method to be copied, press Enter. Use the
and
keys to input the number of the method that is to be
copied. (Do not press Enter yet.)
4. Press the
key once.
14
and
keys can also be used to input the
Publicidad
Tabla de contenido
