Theoretical substantiation of the device parameters for drying the green mass of essential oil crops in a vacuum drum dryer

Abstract

Purpose. To substantiate theoretically the main structural parameters of the device for drying the green mass of essential oil crops in a vacuum. Methods. In the process of theoretical substantiation of the device for drying the green mass of essential oil crops in a vacuum drum dryer, the methods of technical analysis of the movement of the green mass along the blades and the inner surface of the drying drum, planimetry, and trigonometry were used. The dependencies for calculating the design parameters of the device were derived on the basis on algebraic methods. The analysis of the formulas was based on graphical dependencies constructed on their basis. Results. A preliminary experiment using straw mass on the SVB-10 vacuum drum dryer found that a grass bundle is formed in one complete rotation, the central part of which is difficult to dry. To prevent the formation of the grass tourniquet, it was proposed to use L-shaped blades attached to the inner surface of the drum. It was found that to ensure the turning of the green mass and the rational use of the drying drum space, the height of the blade should be equal the length of the L-shaped blade visor. Dependencies have been developed to calculate the angle between the canopy and the blade, the condition for the blade height, their rational number, and the maximum portion mass of green mass that can be loaded into the developed device. A general view of the device for drying green mass of essential oil crops in a vacuum drum dryer was also proposed. Conclusions. Due to the large internal friction angle and low thermal conductivity, it is advisable to use a drying drum with L-shaped blades attached to the inner surface of the drum, with the height of the blade equal to the length of the canopy. The use of L-shaped blades ensures uniform mixing of the green mass of essential oil crops during the rotation of the drying drum and prevents the formation of a harness. The number of blades, their geometric dimensions depend on the radius of the drying drum, the friction angle of the green mass of essential oil crops on the metal surface, the permissible technological gap, and the specified weight of the portion loaded into the vacuum drum dryer. Keywords: green mass of essential oil crops, vacuum, L-shaped paddle, vacuum drum dryer, drying drum, canopy, herbal bundle, drying, friction angle.