Week 5

Week 5

This week we mainly began building our experimental setups for determining the critical pressure for the tube and for determining the leaking rate for the plastic tube. We had already constructed a setup for the glass tube to figure out the leaking rate, so we created the exact setup for the plastic tube.

Leaking Rate - Plastic Tube

We created the same setup for the leaking rate of the plastic tube as the setup for the glass tube since both are approximately the same size. We sealed the gauge to the tube using a vacuum epoxy and then we evacuated the tube and sealed the tube with a rubber cap through teh use of the setup we developed. Here are both tubes with their respective gauges monitoring the internal pressure:

Leaking Rate gauges attached to both the glass and plastic VacuStor tubes

Top View of both gauges attached to their respective tubes

We will be monitoring both tubes now to determine which of these materials will be most effective in maintaining the vacuum, and thus, having the longest shelf life.

Critical Pressure Experimental Setup

We have started building the critical pressure experimental setup, but were unable to finish it this week. Hopefully, we will be able to finish it next week. However, this is what we have so far:

Central portion of Critical Pressure Experimental Setup

In theory, we will have a similar setup to the leaking rate setup, but the gauge will be on the outer tube instead of the VacuStor tube. This is because we only need to know the pressure inside the VacuStor just before we cap it, after which we will puncture the cap with the capillary tubes we fabricated to see how much liquid the vacuum will draw. Once we find the minimum pressure that can draw enough fluid into the tube, we can use this as our reference for extending the shelf life.