EDN146 figure 3
Figure 3. Seed container modified with tire stems at the bottom and top of the seed container. The inner tube was connected to the bottom tire stem, which has its valve core removed to allow gas to flow into the container. The valve core was retained in the tire stem at the top of the bottle so that the valve-core pin could be pressed down (to allow air to escape while the container is being filled with biogas) and then released (to trap the biogas in the container once full). Source: Tim Motis
