METHOD OF HEATING AND COOLING BRAKE PULLEYS OF BELT-BLOCK BRAKE OF DRAW-WORKS AT ESTIMATION OF THEIR THERMAL BALANCE Russian patent published in 2006 - IPC F16D65/813 

FIELD: mechanical engineering.

SUBSTANCE: belt-block brake has hollow pressurized brake pulleys filled with low-melting metal (potassium, sodium, lithium) where heating elements are located over perimeter of cavity. Thermocouple wires are connected to outer surfaces of brake pulleys. Surfaces of first brake pulley are fully heat-insulated from surrounding medium and surfaces of second brake pulley are engageable with it when heating elements are connected to external current source to ensure heating of brake pulleys by molten low-melting metal. Then heating elements are disconnected from external current source and part of heat scattered into surrounding medium by radiation is determined by ratio of measured temperatures of first (t₁) and second (t₂-t₀) brake pulleys. According to second version, belt-block brake is provided with friction linings located over brake band embracing arc; thermocouple wires are passed through them. Projection of first brake pulley is heat-insulated from drum flange and projection of second brake pulley is not heat-insulated. Interaction of friction units of brake is ensured through cyclic braking and brake pulleys are heated by low-melting metal to its molten state. Part of heat of its total amount is estimated by ratio of measured temperatures [(t₁-t₀)/(t₂-t₀)] of first and second brake pulleys at different intensity of radiation and convective heat exchange from their surfaces; heat is drawn to drum flange by conductive heat exchange. Provision is made for estimation of losses of heat in brake pulley of belt-block brake by temperature method for determination of heat transfer coefficients at natural and forced convection and radiation, as well as at conductive heat exchange for proper selection of materials of friction linings and operation at surface temperatures below permissible limits.

EFFECT: enhanced efficiency; possibility of operation at surface temperature below permissible limits.

4 cl, 5 dwg