| 摘要 |
A method for producing at least one oscillation measurement signal, which has vibrations of a vibratory body are registered. A temperature sensor is applied thermally attached with a non fluid contacting, second surface of the vibratory body for producing a temperature measurement signal representing a time curve of a variable temperature of the vibratory body. The temperature measurement signal can follow, however time delayed, a change of the temperature of the vibratory body from a beginning temperature value, to a new temperature value. Based on the oscillation measurement signal as well as the temperature measurement signal, density, measured values are produced representing the density, wherein, during such, discrepancies possibly occurring between the time curve of the temperature of the vibratory body and the temperature measurement signal are taken into consideration, respectively at least partially compensated. |
| 主权项 |
1. A method for ascertaining density, ρ, of a fluid contacting an oscillatably held, vibratory body, especially a metal vibratory body, which can be excited to execute vibrations, wherein the vibratory body has a specific thermal conductivity, especially one greater than 5 W K−1 m−1, and, thus, a thereon dependent, thermal conductivity, effective for heat transfer from, on the one hand, a fluid contacting, first surface of the vibratory body, which has a fluid temperature, namely a temperature of the fluid contacting the first surface, to, on the other hand, a non fluid contacting, second surface, as well as having a heat capacity, and wherein a temperature, of the vibratory body, namely a temperature of the vibratory body dependent on the fluid temperature, is variable, the method comprises the steps of:
causing the vibratory body contacted by fluid to vibrate in such a manner that it executes, at least partially, resonant oscillations, namely mechanical oscillations with a resonant frequency, dependent on the density of the fluid contacting the first surface of the vibratory body as well as also on the temperature, of the vibratory body; registering vibrations of the vibratory body for producing at least one oscillation measurement signal, which has at least one signal component with a signal frequency corresponding to the resonant frequency and consequently dependent on the density of the fluid; applying a temperature sensor thermally coupled with the vibratory body via its second surface for producing a temperature measurement signal, representing a time curve of a temperature of the vibratory body, namely a temperature of the vibratory body dependent on a temperature of the fluid contacting the vibratory body on its first surface; and producing a measured value of density, based on the oscillation measurement signal as well as the temperature measurement signal during a change of the temperature of the vibratory body, especially a change of the temperature of the vibratory body resulting from a change of the temperature of the vibratory body on its first surface, in such a manner that a discrepancy, especially a time dependent discrepancy, occurring during the producing of the measured value of density between the time curve of the temperature of the vibratory body and the temperature measurement signal, is taken into consideration, especially in such a manner that said discrepancy, is at least partially compensated, wherein: the temperature measurement signal, especially as a result of the thermal conductance, and the heat capacity, of the vibratory body, follows a change of the temperature of the vibratory body from a beginning first temperature value, to a second temperature value, only time delayed, a change resulting especially from a change of the temperature of the fluid contacting the vibratory body on its first surface and/or from a fluid change; and so that the temperature measurement signal, corresponds consequently to said second temperature value, only time delayed. |
