In a humidifying and heating apparatus for respiratory gas, a transformer for inductively heating a humidifying liquid is provided in a housing having a socket, whilst a vessel for containing the liquid is made as a separable sterilizable or disposable unit through which the respiratory gas can be passed and which has a plug connector releasably engaged in the socket. The secondary transformer winding is in the form of a plate which is disposed in the plug connector and comprises an upper portion in contact with the liquid and a lower portion straddling the transformer core.

A steam generator (1) for steam baths, in particular steam cubicles, with a column-shaped housing (2) has an electrically heatable water bath (3) acted upon by air in operation, so that the air surrounding the housing (2) is sucked through a ventilator (4) into the housing (2) and recirculated through the housing (2) and through the water bath (3). The housing has a second inlet for insertion of a container holding additives.

A water vapor supply unit having a partition dividing a water tank into two compartments above a water line but allowing communication below the water line. A water level control in one compartment maintains the water level in both. One or more air inlet nozzles for each compartment are provided and are of angular form. They are side wall mounted for adjustment for regulation purposes. Each compartment has one or more vapor outlet fittings. A mount for a water level controller assures its proper disposition when mounted in place.

A respiratory humidifier has a base with a thermally controlled heater therein effective to heat a first transfer surface on the top of the base. Removably pressed against the first transfer surface is a second transfer surface forming the bottom of a container into which liquid is admitted, close to the bottom, by a float valve to establish a liquid level. Gas is admitted to the container below the liquid level through an inlet tube and is released from the container above the liquid level through an outlet tube. A porous pad in the container is in the gas flow path between the inlet tube and the outlet tube to provide extended, wettable surface. A float blocks the entrance to the outlet tube when the liquid level rises unduly and a normally closed shunt passage between the inlet tube and the outlet tube opens by differential pressure when the entrance to the outlet tube is blocked.

Apparatus for humidifying a gas stream comprises a transparent reservoir having a top cap and connected via a float controlled valve chamber beneath to a humidifying chamber. The valve maintains a desired water level in the humidification chamber which has a heated floor and gas inlet and outlet ports in its top. Gas flowing between the ports is humidified to a figure approaching 80% and has its temperature raised to a higher temperature than is required at a point of use. The humidified gas flows through a hose which controls the cooling of the humidified gas so that 100% saturation cannot occur until the gas reaches the outlet of the delivery hose at the point of use. The temperatures of the hose and humidification chamber are separately controlled by their own control loops. The float chamber, reservoir and humidification chamber are made of the transparent material and the float and humidification chambers share a common metallic base which is readily detachable for cleaning.