| 摘要 |
PROBLEM TO BE SOLVED: To provide an inexpensive and accurately detectable sand surface detecting device becoming no hindrance to supplying earth and sand and requring no acting of a new member or water and compressed air. SOLUTION: This device is to detect the sand surface in a sand pile creating hollow pipe 2 of earth and sand 12 inputted to the sand pile creating hollow pipe 2 driven in the processing ground 1. In this case, the device is provided with a microstrip antenna 13 installed on an inner wall of the sand pile creating hollow pipe 2, a network analyzer 8 for receiving a reflected wave from the sand surface through the microstrip antenna 13 by inputting a high frequency sweep signal to the sand pile creating hollow pipe 2 through the microstrip antenna 13 by generating the high frequency sweep signal and an arithmetic processing unit 11 for performing an operation for detecting the sand surface on the basis of frequency characteristic data on the reflected wave received by the network analyzer 8.
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