Bubble Point Testing
Bubble Point Integrity Test
With the aid of the so-called “pressure test”, membranes can be checked for integrity in a simple manner.
What is the test?
Air (alternatively CO2 or N2) is connected to the filter housing and the required pressure of 1.5-2.7 bar is applied for a maximum testing time of 3 minutes. The test pressures for the different pore sizes of the membranes are:
0.45µ @ 270kPa (2.7 bar) 0.65µ @ 200kPa (2.0 bar) 0.80µ @ 150Pka (1.5 bar)
Intact membranes will not allow a continuous stream of bubbles (“boiling” effect in the water-filled vessel) to appear on the outlet side. A few air bubbles (a discontinuous stream) are possible due to air diffusion. The difference between a continuous and discontinuous stream is easily recognized in practice.
If the integrity test is NEGATIVE (membrane failure), it allows for quick discrimination and replacement of the defective membrane.
When to test?
The integrity test is carried out after sterilization and cooling of the filter. It is additionally possible to test after rinsing at the end of a bottling run.
How to test?
• Empty the filter unit by opening the drain valve.
• Slowly apply sterile gas via the vent valve: pressure is approximately 0.2 bar.
• Open the vent valve on the outlet side. Fit the vent with hosing, if it is not already, and immerse the hose into a water-filled vessel.
• Gradually increase the pressure to the test figure (see pressures listed above). The slightest defect, like a minute hole, would cause continuous bubbling.
• If continuous bubbling is not noticed over a maximum three-minute period, the system is intact.
• After test completion, close the vent valve on the outlet side and depressurize the filter via the inlet vent valve.The filter is now ready to use.
Paul Hoover, Owner/Winemaker
Still Waters Vineyards
Winery Equipment Testimonial:
"Upgrading your winery from 1000 cases per year to 3000 to 5000 can be a daunting task. The choices in winery equipment, capacity and price vary all over the place. The great thing about Ryan is, having been a wine maker for years, he knows how to design things from start to finish. When I harvested my first ten tons of the year at 6:30 a.m., Ryan and his staff were there making sure everything was working correctly. I knew I had made a good decision."