Automated Control System for Circulating Bathtub of Floating Salt Water

Background/Objectives: The purpose of this study is to control the constant salinity of floating salt water due to the problem of that the increased salinity as time passed causes strong skin stimulation because a medical bathtub system for float spa is required to sustain constant temperature. Methods/Statistical Analysis: The measuring method of salinity is to detect gravity. A basic gravity of floating salt water is 1.2 with 31% (brix) of a salinity and applied detecting method to find that the gravity becomes 1.4 with 33% (brix) of salinity. A buoy is submerged when the gravity becomes 1.2. Meanwhile, when the gravity becomes 1.4, a buoy attached magnetic is floated to upper part of tube where is attached a reed switch using the principle of floating of buoy, the reed switch makes short circuit to control the salinity. Findings: This salinity sensor to control its concentration is attached in the bathtub of floating salt water. It is possible to provide a low salinity of floating salt water for an operating supply pump of floating salt water after detecting signal from the salinity sensor. Improvements/Applications: An average user who has a delicate skin condition appealed severe skin stimulation after using the existing bathtub of floating salt water as time passed. But people who used the bathtub adapted the control device has no skin problems as time passed.