| 摘要 |
<p>The present invention relates to a device for measuring density or determining the presence and the amount of materials of different density in an object (9, 18) to be measured, of a solid, liquid or gaseous material, said device comprising at least one source of radiation (5, 12) for emitting electromagnetic radiation, and at least one sensor (6, 13) for measuring the radiation intensity, so positioned as to absorb radiation from the source of radiation (5, 12) and being connected to a calculation unit (8, 16). In accordance with the invention the device emits radiation of at least two wavelengths and comprises measurement means for determination of the extension of the object (9, 18) between the source of radiation (5, 12) and the sensor (6, 13). In addition, the invention relates to a method of measuring density, comprising radiating electromagnetic rays through an object (9, 18) to be measured and measuring the radiation intensity on the ray-exit side of the object (9, 18) to be measured. In accordance with the method the extension of the object (9, 18) is measured along the path of the radiation through the object to be measured and the radiation is effected at least at two different wavelengths.</p> |
