Silos that are filled by bulk trucks (also known as road tankers) have several equipment to be controlled for safe and efficient silo loading. Automatic filling control system has a PLC controlled electrical panel that has full control over silo equipment. Silo top jet filter, silo inlet pinch valve, level sensors, pressure sensors and other components are connected to control panel. The power of air compressor of bulk solid tanker truck is supplied by built in power supply plug. Silo filling control system checks silo before filling for safety, controls the power sent to bulk truck, checks the product level, silo inner pressure during silo filling. System both controls the equipment and protects the silo from overfilling and over pressure. Silo top air vent jet filter, silo pressure sensor, silo level sensors, pinch valve , pressure relief valve, explosion vent panel, pinch valve and other silo components are connected to silo control system.
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Truck driver connects the hose to silo filling pipeline. Pushes start button on the panel.
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Silo control system automatically checks silo for safety.
A self test is applied on pressure relief valve, dust collector (silo top jet filter) , process air supply and silo level. If any problem is detected (high level, malfunction in pressure relief valve or jet filter) , system does not allow filling, does not supply power to truck and keeps pinch valve closed.
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If silo is not full, jet filter and pressure relief valve self tests are passed, system starts operation.
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Silo top jet filter (dust collector) is operated.
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Pinch valve is opened.
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Power is provided to bulk truck to start filling.
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Product level in the silo is continuously measured during silo filling.
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Silo pressure is continuously measured during silo filling.
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If the pressure inside the silo rises over the limits (overpressure), silo pressure relief valve opens to decrease the silo pressure , a signal is sent to electrical panel to stop filling. Built in pressure sensor is also available for double protection if the pressure relief valve malfunctions. In this case the signal coming from pressure sensor is used to stop filling.
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Electrical panel closes the pinch valve and cuts the power of truck immediately after receiving the overpressure signal.
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If the powdered product in the silo reaches top level, system sends audible alarm to the truck driver to stop truck compressor. After a definite time, truck power is cut, pinch valve is closed and dust collector is stopped.
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Truck driver removes the hose from silo filling pipe.
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Process values are recorded for future use.
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