SU1325269A1 - Method of heat treatment and drying of capillary and porous articles and materials - Google Patents

Abstract

The invention can be used for drying and heat treatment of heat insulating plates made of foam plastic, gypsum concrete slabs and panels, as well as reinforced concrete slabs in industrial materials of the construction materials. The invention improves the quality of drying and intensifies heat and mass transfer. Heating of products (I) 7 in chamber 1 is carried out at a rate of 40-50 ° C / h. At the same time, the difference in t-ry between the surface and the center of And 7 is 4-. After warming up And 7 to the t-phase phase transition of the liquid component, they are cooled by natural air exchange or by operating a recirculation system with a partial release of the exhaust vapor-air mixture, the mixture T-ru in chamber I is maintained equal to 55-70 C. The distance between the center and the surface is 3-10 ° C. After reaching the specified gradient, the tors in And 7 heat the latter to 85-100 ° C and thermostat the E7. 3 sludge. with $ SL

Description

The invention relates to the technique of drying capillary-porous materials and can be used for drying and heat treatment of heat insulating foam plates, gypsum concrete plates and panels, as well as reinforced concrete slabs and structures in the construction materials.

Fig. 1 shows an installation for implementing a method for drying articles made from capillary-porous materials; FIG. 2 is a section A-A in FIG. 1; Has fig.Z - section BB in FIG. 1.

The installation contains a heat-insulated chamber 1, the solenoid 2 windings placed inside it, made around the perimeter and length of chamber 1, thermal electric heating elements 3 (TENY), the lower air-exchanging channel 4 with exhaust pipe 5, and chutes 6 for laying processed products 7, resistance thermometers 8 (dry and wet), the corridor 9 controls are located in the end part of the chamber, an automatic actuator valve 10 placed in a chimney 5, a regenerator 11 for cooling air, an air preheater 12 with a fan nic, recirculating loop raspredelitelnp control console 14 and the control board 13,

The method of heat treatment and drying of capillary-porous products and materials is carried out as follows.

Processed products 7, for example, heat insulating plates made of foam plastic, gypsum-concrete slabs or panels, or reinforced concrete slabs and structures, are placed in a stack on trolleys 6 and placed in chamber 1. Turn on the coil of the solenoid 2 and heating elements 3 to the maximum power value and heat the products to the phase transition temperature of the liquid component of products 7, for example, in the case of water, heating is carried out to 100 ° C at a speed of 40-50 C / h, while the temperature difference between the surface and the center of products 7 is 4-14 ° C. For thermal insulation foam boards FS-7-2 asta temperature drop is maintained at 8-14 C., and gypsum concrete for slabs and panels, as well as concrete products and structures equal to 4-8 ° C,

The rate of heating of the product and the temperature difference between the surface and the center of the processed products 7 is determined by the readings of thermometers 8

resistance and thermocouples, the sensors of which are buried in the regular places of the products 7 when they are placed on carts 6

The heating rate and temperature difference are controlled by varying the power of the windings of the solenoid 2 and heating elements 3. If the temperature between the lower and upper products in the stack exceeds 10-12 ° C in the heating process, then the recirculation system is turned on, while the valve 10 is closed.

After heating the products to the temperature of the phase transition of the liquid component, the windings of the solenoids 2 and heating elements 3 are turned off and the products 7 are cooled by means of natural air exchange when the valve 10 is open or due to the operation of the recirculation system with partial discharge of the exhaust air-vapor mixture. The temperature of the mixture in the chamber is 55-70 ° s The products 7 have a high heat capacity, so their cooling is uneven and a temperature gradient is formed in the products, directed from the center to the surface. When the temperature difference between the surface of the products and the vapor-air mixture is 12-18 ° C, the difference between the center and the surface of the products 7 is 3-10 ° C. The indicated temperature difference is recorded by resistance thermometers 8 and thermocouples, the sensors of which are located in the products 7 themselves. For heat insulating boards made of FS-7-2 foam, the optimum temperature difference between the center of the plates and their surface is 3-5 ° С5 for reinforced concrete products and structures 4-8 ° С, and the density of gypsum-concrete plates and panels is 7-10 ° С

After the specified temperature gradient in products 7 is reached, the solenoid 2 and heating element 3 windings are again turned on to maximum power and products 7 are heated to 85-100 s and thermostatting is performed for a time that is selected for each product depending on the regulation

ment requirements. I

Then the heating is turned off and the cooling is carried out to 35-40 ° C, after which the carts 6 with parts 7 are sent for unloading.

Claims (1)

Invention Formula The method of heat treatment and drying of capillary-porous products and materials by heating them to the phase transition temperature with subsequent cooling during convection of the steam-air mixture, characterized in that, in order to improve the quality of drying and intensify heat and mass transfer, the product is heated at the rate of AO-ZO C at maintaining a temperature difference between the surface and the center of the product; anger, and the cooling of the product is carried out at a mixture temperature of 55-70 ° C until the temperature gradient in the product is directed from the center of the product to its surface and equals 3-10 ° C, after which the product temperature again increases to 85-100 ° C and carry out its thermostatic control. ) Uz.z  Rig.Ъ