| 摘要 |
PROBLEM TO BE SOLVED: To provide a tensiometer as improvement of a conventional one equipped with a pressure converter involving such problems as degradation of the measuring accuracy and promotion of cumulation of the leaching air owing to the use of a pressure converter for air, degradation of the responsiveness and an increase of the amount of the leaching air resulting from forming the body from a polyvinyl chloride pipe, and turbulence of the periphery of a porous cup, destruction of the pressure converter, etc., likely when the leaching air is to be removed. SOLUTION: The tensiometer is composed of a transparent polyvinyl chloride pipe 2 furnished with a P-cock 1 ranging from the top to below, an upper and a lower valve socket 3 made of polyvinyl chloride connected to the pipe, a full-bore type ball valve 4, nipple 5, and cheese pipe 6 provided between the valve sockets, a bushing 7 and pressure converter 8 installed beside the cheese pipe, a stainless steel pipe 9 connected with below the valve sockets, and the porous cup 10 having water permeability connected to the stainless steel pipe, whereby the arrangement is partitioned into upper and lower parts by closing the full-bore ball valve so that the upper part is used as an air sump while the lower part is formed as a measuring system, and the water content of soil is determined by measuring the water tension of negative pressure in the measuring system by the pressure converter.
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