Description
The workplace is equipped with two large dimension tanks with accessories for thermal processing of cast iron with dimensions 8000 mm x 7000 mm x 5300 mm with total filling volume of approximately 260 m3. The external walls of the tanks are produced from steel sheet metal 8 to 12 mm thick. The tanks are identical in dimension and different filling is used. The main filling is a mixture of polymer and water in defined ration 5 to 16 %. The second tank includes water. The tanks are designed open on the top with border without closing lid.
The load structure for removable frames with the grids with sufficient free space for stirred capacity, water, and polymer at the defined height above the tank bottom. The grid load capacity is 35 tonnes of even load, surface load is approx 1000 kg/m2.
The stirring in the tank is provided by 8 propeller stirrers with diameter up to 750 mm. The speed of moving liquid with the stirrer is up to 1 m.s-1 with the option of reduction by means of frequency converter. The tank bottom includes the liquid flow turning device which rotate the flowing liquid upwards and provide even bypass of immersed casting during thermal processing. The tank work temperature is within range 5 to 50°C depending on the thermally processed casting material.
Every tank includes the liquid (water) drain by a pump in the cooling exchanger. Entry to the cooling in the upper part, where the polymer is the warmest. The control system checks the tank cooling as per entered parameters during the hardening process and it is possible to control the heating of polymer tank, if the temperature in the tank is lower than required. During hardening and in between the hardening cycles, the tank stirring is controlled for correct mixing and oxygen supply in case of the tank shutdown.
Technology for cooling is designed as compact free-cooling unit with cooling output approximately 200 kW. This configuration cools water or the polymer with volume 260 m3 from temperature approx 35°C to 30°C. Under specific conditions, it is possible to cool up to decline (25°C to 20°C). The system comprises of desk dismountable exchanger + cooling unit. The circuit between the cooler and the exchanger it with 35 % propylene glycol.
The unit contains cooling circuit equipped with SCROLL compressors, pipe evaporator for industrial applications, capacitors placed on one side of the cooler and atmospheric cooler on the other side. The sections are separated using partition and it is impossible to affect the cooler with heated air from the capacitor side during concurrent operation of both technologies.
The workplace includes both tanks with stirring and cooling is via the annealing surface with maximum temperature 1150°C, handling crane with load capacity 35 tonnes. All technologies are controlled and checked using control system with visualisation.