Test Speed: Ramp and Step Curve
Types
RAMP
The rate of
pressure increase can influence the measured pore size. It takes time to empty
pores, especially for thick samples and tortuous pores. Faster pressure ramp
rates will lead to the pressure increasing before larger pores have emptied,
creating the appearance of smaller pores. Excellent repeatability can be
achieved by maintaining a constant ramp rate. For greater pore diameter
accuracy, use a lower ramp rate.
STEP
The step mode
allows flow to stabilize at each pressure before advancing to the next
pressure. The test proceeds more slowly, but with greater pore size accuracy.
A higher
resolution setting collects more points, but at the cost of longer measurement
time.