Abstract: A flexible, water impervious liner is fitted in a rigid outer shell. The shell has an open top with a peripheral flange over which a top lip of the liner is fitted. A separate top plate attaches to the flange with standard fasteners for clamping the liner to the shell. Through hull fittings are provided for heating elements at the side and inlet/outlet fittings at the top. The construction allows convenient access to virtually all components of the water heater, including the liner and the heating elements, so that they can be quickly and easily serviced or replaced. A desired amount of insulation can be provided by an appropriate cover or blanket to surround the outer shell.

Abstract: Thin, flexible sheets of water-impervious plastic material have their margins heat-sealed together and enclose a layer of insulating material of a size sufficient to cover the internal area of a tub. An internal bladder is of a size sufficient to cover at least the major portion of the water surface area of the tub, is supported on the intermediate sheet and itself is covered by a thicker, weather-resistant top sheet. The margins of all of the sheets are secured together and adapted to be secured to the curb or deck of the tub.

Abstract: An electric motor has an upright axial drive shaft carrying a blower at the bottom and a separate fan at the top. The blower supplies a strong flow of air for aerifying water contained in a whirlpool bath or tub and the fan supplies a secondary flow of air for cooling the motor. A housing mounting the motor has a bottom bowl section forming a first plenum for air blown by the blower and a top dome section forming a second plenum for air blown by the fan. The two plenums are substantially sealed from each other so that the fan continues to supply air to cool the motor and maintain it at its designed operating temperature regardless of whether or not the primary air flow is prevented or reduced, such as by an obstruction.