US Patent 9109711 Apparatus to visually indicate a leak from a relief valve

Apparatus to visually indicate a leak from a relief valve are disclosed. In one example, an apparatus is disclosed that includes a pipe plug having a head and a shaft. The pipe plug is to attach to a relief valve. An opening is to extend through the head and shaft. The apparatus also includes a first flexible membrane to cover an end of the opening. In some examples, the first flexible membrane is to expand when fluid is released via the relief valve into the opening of the pipe plug.