Moxa shape dependence on the combustion characteristics and the heating characteristics in Chinetsukyu style moxibustion

Abstract

[Objective] In Chinetsukyu, a burning moxa cone is removed when the patient begins to feel heat or warmth. As a standard for removing moxa, the burned ratio was used, but the range of the ratio is wide from 70% to 90%, and the temperature is considered to be different. 　In this study, in order to remove the moxa at the target temperature, the relationship between the temperature and the combustion height is clarified by using moxa with different shapes and hardness.[Method] The moxa cones had a conical shape with bottom diameters of 20 mm and 10 mm. The height and density were changed. The temperature at the center of the bottom of the moxa was measured using a K-type thermocouple. The target value of the rising temperature (ΔT ) to feel warmth was set to 15℃. The burning time is the period from ignition to 15℃, and the heating time is the period from 1℃ to 15℃. The combustion height is the distance from the bottom of the moxa to the combustion area.[Results] As the moxa height increased, the burning rate and burning and heating times all increased. As the moxa density increased, the burning rate decreased, and the burning and heating times increased. The combustion height for ΔT =15℃ was less dependent on moxa height and density and became half the bottom diameter. In order to investigate the relationship between the combustion height and the moxa shape in detail, the rising temperature was formulated. If the moxa was high or density was low, the combustion height for ΔT =15℃ was higher than half the bottom diameter. If the moxa was high or density was high, the amount of heat per second of radiant light decreased.[Conclusion] In order to remove moxa at ΔT =15℃ as the target warmth, the height of the moxa and density of the moxa dependencies on the combustion height were small. As the standard to remove the burning moxa at ΔT =15℃, the combustion height of half the bottom diameter could be used. If the moxa height is high or density is low, the moxa should be removed slightly before the target height. It is considered that the smaller or softer the cone, the larger the amount of heat per second, and the better the heating characteristics.