Principle: Permeability is determined by measuring the time required for air at standard volume and pressure to pass through the sand specimen. The Permeability Meter determines how easily air can pass through the molding (core) sand. A constant pressure output is provided by a miniature fan which is driven by a special electronic speed controlling motor. The pressure air will go through the big or small orifice. After the specimen is placed on the specimen pedestal, the pressure air will pass through the sand specimen and the permeability result is calculated by the micro-computer of the machine and shown on the LED display. Feature: Constant pressure output: The pressure output is controlled by a single chip microcomputer instead of an air drum dropping. Specimen pedestal of switching automatically: The machine is fully automatic. Simply place the specimen on the specimen pedestal and press start. The operator doesn't need to select the big or small orifice. The micro-computer of the machine will judge the close/open of the big and small orifice automatically. High precision: A constant pressure output, a high precision micro pressure sensor and a 41/2 AD digital acquisition system make this machine to have a higher precision. Data storage: In the case of the shutdown of the machine or power failure, the test data has been stored in the computer system of the machine. Printing: An interface is provided on the rear of the unit so that it may be linked directly to a customer supplied computer or printer. Main technical parameters: SIZE:410X330X260MM WEIGHT:15KGS