a device for testing the compactibility of a sample of granular material is described including a delivery structure with an invertible riddle , a testing structure with a plunger to compress the sample and an encoder to measure the compactibility of the sample , and a specimen tube mounted on a carriage which traverses between the delivery and testing structures . a wiper levels the sample within the specimen tube . the floor of the specimen tube can be raised to eject the sample after testing and the same wiper cleans the raised floor . a control panel activates and coordinates the operation of the device .