| 摘要 |
PURPOSE:To enable continuous measurement of a concn. with high accuracy without disturbance by foam by the construction in which a chemical liquid intake pipe and a pipe for discharging the chemical liquid together with foam is provided in the upper part of a flow cell for measuring the concn. of the chemical liquid by absorbancy and a pipe for discharging the foam-less chemical liquid is provided in the bottom part thereof. CONSTITUTION:An intake pipe 52 for a sample chemical liquid 55 in a tank 54 and a pipe 53 for discharging the liquid 55 together with foam from a foam well 58 are provided in the upper part of a flow cell 51 in the case of measuring continuously the concn. of the chemical liquid for the purpose of controlling the concn. of the chemical liquid contg. a foamable chemical such as H2O2 or the like, which is an etching soln. or the like used for producing semicondutors. A pipe 59 for discharging continuously the chemical liquid having no foam is provided in the bottom of the cell 51. Pumps 57 and 60 are controlled to form a foam well 58 and an optical measuring region 61 for the liquid 55' having no foam in such flow cell 51, so that the continuous measurement of the concn. of the chemical liquid with high accuracy without disturbance by the foam is made possible. |
