Abstract: A hydraulic demonstration apparatus is disclosed having a hydraulic system including a reservoir, an inlet line and an outlet line. A valve at the inlet line is included for introducing air so as to create aeration in the hydraulic system. A restricting valve is provided at the inlet line for creating cavitation in the hydraulic system. A hydraulic pump is provided having a clear cover for observing the effects of aeration and cavitation inside the pump. A flow meter having a clear housing is provided for observing the air in the system and the reduction of pump efficiency caused by aeration. The demonstration apparatus can be mounted on a movable cart.

Abstract: A pulling device for use with a pipe having an inside wall. The device includes a center slide. The device further includes at least one gripper plate that is adapted to cooperatively engage the center slide to cause the gripper plate to expand outwardly with respect to the center slide. The gripper plate includes a plurality of rings for engaging the inside wall of the pipe. The device further includes a pulling eye attached to the center slide to which a swivel or a cable can be attached to pull the device.

Abstract: A shut-off valve for pressurized fluids in particular for air cooling/heating apparatus includes at least one condenser and at least one fluid evaporator communicating with each other by a pipe at least one duct which has inside a nozzle coaxially formed with a capillary duct designed to cause rapid expansion of the fluid when it emerges from the nozzle, and a retainer securing the pipe to the valve.