PVC Container Design

---

• Rubber Seal
• O-Ring Placement
• Schrader Valve
• Threads

---

Rubber Seal

The original safety container had a rubber seal installed inside the cap that the end of the PVC pipe tightened against. For a tight seal, the lid had to be tightened more than it could be comfortably tightened by hand. The Center looked at other methods that would improve the seal and require less torque to tighten the cap.

O-Ring Placement

Different designs were tried using O-rings (figure 6) rather than a flat rubber washer for the seal between the cap and the safety container. The O-ring helped but it still required too much torque to obtain a tight seal. Figure 7 shows some of the different designs we tried. The design that appeared to have the most promise had the O-ring placed in a groove machined in the pipe. The cap slid over the O-ring to provide the seal (figure 8). A similar version placed an O-ring between the end of the male threaded fitting and the inside of the cap (figure 9).

Figure 6—One design testing O-rings
to seal the PVC safety container.

---

Figure 7—Different O-ring designs that were tested.

---

Figure 8—The O-ring design that appeared to provide
the best seal had the O-ring installed in
a groove machined in the pipe.

-Continued-