| 摘要 |
<p>1. Towed densimeter system for the continuous measurement of the density as a function of the depth of marine silt, comprising - a fish towed by a tug and equipped with a means of measuring the density of the marine silt through which it passes, and with a depth sensor ; - a cable making it possible to tow the fish and to transmit data ; - a winch for manoeuvring the towed fish, as a function of the data which it has transmitted ; - means for determining the position of the tug relative to fixed points on land ; characterized in that : - the said towed densimeter system functions in an autonomous manner and comprises means for locating the towed fish (1) relative to the tug (4) ; - the towed fish (1) has a hydrodynamic, pressure-balanced profile and is designed to enable it to pass through a marine silt (5) of density up to 1.4 at a speed of at least two knots ; - the means for measuring the density of the silt (5) traversed is a high-speed nuclear transmission probe comprising a radioactive source (19) and a sensor (21) and provided with safety shields against radiation ; - the winch (3) is controlled by a computer (55) as a function of the data transmitted, the said computer (55) being installed on board the tug (4) in order to collect all the data transmitted by the fish (1) and also to record the time and the position of the tug (4) in the harbour, to establish at regular intervals an average of the instantaneous count rates of the sensor (21) and to convert it to a density reading, to store all the data in its main memory, to retrieve and calculate all the inter-relationships and, in response to the results obtained and as a function of a preselected programme, to regulate and control the operation of the winch (3) so that it causes the towed fish (1) to ascend or descend in order to seek a preselected depth or density, or causes it to follow an undulating trajectory within a preselected contour of density, and to display the synthesis of the readings with the aid of a visual display device (62, 63).</p> |
