The textbook is developed on the basis of "Methodical instructions and control tasks for students of distance learning , The mountains , Metallurgical , Electrical Engineering and Automation and Technological Specialties , as well as technological specialties, Electrical Engineering , Electronic Engineering and Automation , Chemical-Technological and Engineering-Economic Higher Education Institutions" and edited by C. M. Targa in the publishing house "High School" in 1983. The teaching aid is intended for correspondence students studying in the following areas: 35. 03. 06 Agroengineering, 19. 03. 03 Foods of animal origin, 15. 03. 02 Technological machinery and equipment, 35. 03. 02 Technology of logging and wood processing industries.