To enhance defoaming effect without changing the form of a defoaming vessel, increasing the output or changing the position of an ultrasonic generator and working a liquid to be defoamed by making the degree of unsaturation of dissolved air concentration in the use condition of an ultrasonic propagating liquid equal to or above a specific value.
In the deaerating means 20, the dissolved air concentration under the use condition of water 14 of the ultrasonic propagating liquid is reduced and the degree of the unsaturation of the dissolved air concentration under the use condition of water is controlled to ≥10%, preferably about 50%. The deaerated water flows-in to a jacket 9 again through a liquid introducing pipe 18 by opening a flow-in valve 21. Since the irradiation of the material to be deaerated with ultrasonic wave is performed by using the water having ≥10% degree of unsaturation of the dissolved air concentration under the use condition as the ultrasonic propagating liquid, a photographic emulsion coating solution 10 is stably and efficiently irradiated with ultrasonic wave to enhance the deaeration effect.
NISHI YASUO
SAKURAI TAKESHI
