| 摘要 |
A liquid level transmitter in which the level of liquid in a tank is detected by a sensor formed by a housing attached to the tank over an opening therein, the housing having a fill chamber defined by a sensing diaphragm which is exposed to the liquid in the tank and an insert incorporated within the housing and spaced from the diaphragm. The sensor housing is joined by a support tube to the body of a force balance meter which includes a pivoted force beam whose lower extermity is mechanically linked to a force measuring diaphragm disposed in a diaphragm chamber. The fill chamber of the sensor communicates with the diaphragm chamber of the meter by way of a capillary extended through the coupling tube. The fill chamber, the capillary and the diaphragm chamber contain hydraulic fluid, whereby tank liquid pressure imposed on the sensing diaphragm is transferred hydraulically to the force measuring diaphragm to deflect the force beam. In order to compensate for the effect of temperature on the volume of the fill in the fill chamber, the insert is formed of a metal having a low coefficient of expansion relative to that of the sensor housing whereby the volume of the fill chamber varies in proporton to changes in the volume of the fill.
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