| 摘要 |
FIELD: applicable for preheating of hydraulic circulating systems, hoisting-and-conveying machinery when used in cold climatic areas. SUBSTANCE: the system comprises a switching device, in which the control members are cut in the preheating circuit. With this in view for different working conditions of the hydraulic cylinder: "Rest", "Rod moving-in", and "Rod moving-out" provision is made for the respective circuits. An essential ground for realization of circulation without pressure in the rest condition is the presence of an additional channel in the rod through which oil is fed to the hydraulic cylinder. Realization of the invention provides for preheating of the no-load running hydraulic circulating system and, owing to it, elimination of damage of functional members. EFFECT: enhanced service life of wearable parts and reliability of operation of hydraulic system. 4 cl, 2 dwg
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