One: the principle and composition of spray granulation machine: The quality of granular materials directly affects the appearance, mechanical properties and temperature resistance of PTC ceramics. Granulation is to add a certain amount of adhesive in the grinding of fine powder, granulation is a very important process in the production of PTC heat-sensitive ceramic sheet. After uniform blending, the granular powder is formed, which has good fluidity and compressive ductility, so that the films with better strength and less delamination cracking can be obtained in the process of pressing.
Industrial production using spray drying granulation, the basic principle of the powder with adhesive, spray into the granulation tower atomization, the tower in the droplet by the heat flow in the tower into granular powder, and then discharged from the bottom of the drying tower. And each system also includes some related equipment.
The company adopts the pressure-type spray granulation dryer mainly by the feeding system, drying system, dust removal system, heating system and electrical system components. The filter is extracted and transmitted by the diaphragm pump, and the feeding system consists of a stirring barrel, a filter, a diaphragm pump and an airbrush. The ball mill two times slurry from the ball mill transferred to the mixing barrel.
Then through the spray gun into the drying tower, the specific process is divided into three stages: slurry from the spray gun nozzle into the drying tower began spraying granulation drying process.
Two: The energy of the pressure converts to kinetic energy: 1. Slurry atomization. The slurry is pressed from the nozzle into the drying tower with a certain pressure from the diaphragm pump in the feeding system. Slurry from the bottom up from the nozzle spray, forming a layer of high-speed liquid film, the liquid membrane immediately split into droplets.
The droplet size of the atomization is inversely proportional to the pressure, and the production capacity of the nozzle is in direct proportion to the square of the pressure, and the hot air is entered into the tower by the hot air distributor on the top cover. 2. The mist grains dry into the ball. The mist particles work with the hot air in a mixed flow manner. The hot air distributor takes place a downward streamline air flow, and the droplet is injected from the bottom upward into the hot airflow.
The droplet is spherical by the appearance of tension, at the same time, because the droplet has a large external product, in which the water evaporates rapidly and dries, and the final contraction forms a dry spherical granular powder, which is separated from the hot air. 3. Granular powder discharge. The formed spherical granular powder is gradually settling in the drying tower. The funnel cavity in the lower part of the tower causes the particles to be assembled and discharged from the discharging port. The finer particles, together with the dry air, are extracted by an exhaust fan connected to the upper part of the funnel and into the dust removal system.
The drying tower is composed of the air blower, the drying tower and the exhaust fan. More fine particles into the bottom of the Separator collection barrel recovery, dust removal system by high efficiency cyclone separator, bag filter, centrifugal fan and so on. The exhaust fan feeds the finer particles together with the dry air into an efficient cyclone separator. After effective separation.
The remaining containing a very small amount of fine particles of waste gas from the centrifugal fan inhalation bag dust collector after another dust collection, to achieve the harmless disposal of waste gas, the final exhaust from the chimney discharge. Heating systems composed of electric heaters and gas-fired hot stoves provide hot air for drying towers. Electrical control cabinets and equipment in the inlet and outlet and the discharge of the monitoring temperature of the field sensors, such as the composition of the electrical system of the entire spray granulation dryer monitoring and control of all major links, in addition, to ensure the normal operation of the entire equipment.