Abstract: The mechanically operable plug device is for use with the end of a pipe or conduit. The plug device is for removably sealing the conduit end so that the conduit can be tested for leaks. The mechanically operable plug device is comprised of two spacially parallel plate members, a narrow, elastomeric, and radially expandable O-ring member which is disposed between the plate members, and adjustable lateral force means which is operable on the parallel plate members. The radially expandable O-ring member has a circumferentially disposed surface for engaging the interior surface of a conduit to be sealed, and a generally V-shaped cross section having inclined surfaces of a predetermined slope. The plate members have interiorly facing tapered shoulders of generally the same predetermined slope to engage the inclined surfaces of the O-ring.

Abstract: An improved liquid aerating rotor assembly comprises a support frame having a rotor mounted for rotation about a horizontal axis. A plurality of floats support the rotor and support frame on the surface of a sewage pond or the like. A V-shaped deflecting plow or V-shaped front float is located upstream of the rotor. This configuration causes the upstream surface layer of liquid to pass around the rotor. This prevents any solid debris located in the surface layer of liquid from jamming the rotor and allows more complete aeration of sub-surface liquid. Alternatively, a scoop may replace the V-shaped deflecting members.