Design of a machine for processing medical waste by the thermochemical method

The article deals with issues related to the development of the design of a medical waste processing machine based on the thermochemical method, special attention is paid to the cutting equipment used in the machine. The problem statement is formulated as follows: to design a machine that allows realizing the possibility of processing medical waste by the thermochemical method; offer design options for the cutting equipment of the machine and justify the choice of knife material based on finite element modeling. The design of the machine is proposed, consisting of a base on which an electric motor is located, the movement from which is transmitted by means of a V-belt transmission to the tooling drive. Processing and disinfection of medical waste is carried out in a sterilization chamber. The sterilization chamber and the tank associated with it are structurally the most complex. The main structural elements of the tank are the base, the sterilization container and the lid. Direct processing of medical waste is carried out by rotating the rotary assembly with tooling. In the proposed machine tooling includes four movable horizontal and two vertical knives. During the processing of medical waste, the working surfaces of horizontal knives are exposed to a number of factors that lead to their intensive wear. The article offers several designs of knives to increase their durability. In order to check the correctness of the choice of material and the influence of operating conditions, a FE model was developed for the process of heating a knife under the action of a friction force caused by polyethylene chips descending along the front surface. Calculations were made for two knife materials: carbon steel and gray cast iron. The simulation results showed that, according to a number of criteria, gray cast iron is the most preferred knife material. The use of cast iron will ensure the rapid achievement of the required temperature in the sterilization chamber, and lower internal stresses will reduce the likelihood of knife breakage. To improve the reliability of the machine, design options for movable knives that are subject to the most intense wear are given.