| 摘要 |
<p>GRAIN PROBE A grain probe consists of an elongate hollow tube. The tube has a solid nose with a tapered end and a helical rib on its outside surface. The rib has a short radial extent, considerably less than the diameter of the tube. Immediately following the helical rib is a sampling valve with a sample opening in the side wall of the tube. This is covered by a valve sleeve that slides between a closed position covering the opening and an open position engaging a the end of the helical rib. The valve is retained in the closed position by a cut-out in the end of the sleeve engaging over a stud projecting from the wall of the tube. The cut-out is L-shaped and oriented so that rotation of the tube to drive it into grain will keep the stud engaged in the cut-out. The valve sleeve may carry ribs projecting into the surrounding grain to ensure that when the cut-out and stud are disengaged, the sleeve will remain stationary in the grain while the tube moves to open the sample opening. The tube is segmented to provide for ease in handling when not in use and also to enable the tube to be varied in length.</p> |
