Abstract: A fill level indicating device of the rod-in-tube type has a pair of propping struts gusseting the vibratory tube to the membrane and to the membrane support. One strut is arranged above the vibratory tube and the other below, with both struts aligned in a common plane which is vertical when the device is installed in a container. The vibration excitation and detection systems are arranged on the membrane at 90.degree. to the plane of the struts, so that with the device installed in a container the direction of vibration is horizontal. The membrane is made with thickened portions extending through its middle in the direction of vibration. Material may be removed from the thickened portions by grinding or filing to tune the device to the desired resonant frequency.

Abstract: A level control instrument for controlling and/or indicating the filling level for liquid, powder, granular, especially light-weight bulk material in a container. The level is determined by a single rod shaped vibrator that is actuated by a vibration exciting and measuring system. The vibrator is a rod adapted to act as a bending vibrator which is dampened by bulk or liquid material. The dampening is controlled by the vibration exciting and measuring system. In order to prevent the vibrating energy from being transmitted to the container wall, the vibrating rod has two supports spaced from each other with each located at a nodal point on the rod. One free end of the rod extends into the material containing space of the container. If the two supports are at or near to the points where the vibration nodes appear when the rod is excited to bending vibration it is practically impossible for the vibration energy to be transferred to the container wall.

Abstract: To provide a precise determination and/or control of a filling level in containers, two vibrator elements (10, 12; 48, 52) are arranged one on top of the other and/or coaxially to each other, and at least partially encompass themselves in spaced relation to each other. They are configured like rotary vibrators having the same resonance frequency and are excited to vibrations of opposite sense of rotation for determining the filling level, whereby only one vibrator element comes into direct contact with the filling material in the container. This results in no vibration energy being transmitted to the container walls and thus the quality of the measurements is increased.