| 摘要 |
PURPOSE:To make a uniform upper and lower temperature range in a bath tub and keep a comfortable feeling during taking bath and a high efficiency of additional heating by a method wherein the outlet port of one of heat exchangers is divided by a distribution part and the mixture of air and hot water is injected and supplied into the bath tub through a venturi and an air pipe by way of the other heat exchanger acting as a bypass circuit. CONSTITUTION:When a setting unit 34 is set to an additional heating mode, a heat exchanger B is heated at a combustion part 32 to make an additional heating of water in a bath tub 20 under a circulation action. Simultaneously, a driving valve 35 is opened and a feeding of small amount of water is started at a flow rate restricting part 25 within the heat exchanger 17, injected toward a venturi part 40 at an extremity opening end 39 of a fine hot water feeding pipe 23, the air (a) is sucked under an ejection effect from an air pipe 43 at the negative pressure part 44 so as to form the mixture of air and hot water and then the hot water at the additional heating is mixed to make air bubble mixed condition. As a result, the mixture may flow into the bath tub without decreasing a characteristic of circulation, a uniform upper and lower temperature range can efficiently be accomplished and then a comfortable feeling and a convenient use of the unit can be assured under an effect of bubbles. The heat exchanger 17 has a larger thermal conducting area than that of the heat exchanger 18, resulting in that a waste heat caused by a thermal conduction and radiation thermal conduction from the combustion part 32 is recovered. |
