JPS585221Y2 - Heat-resistant structure of diaphragm level detector - Google Patents

Description

[Detailed description of the invention] This invention transmits vibrations generated by applying a pulse current to an oscillation coil to a diaphragm, and attenuates the vibrations depending on the presence or absence of contents such as a silo at the location where the detector is installed. This invention relates to a heat-resistant structure of a diaphragm type level detector that electrically detects time differences and is used to detect the level of contents.

Conventionally, in this type of level detector, an oscillation coil is provided very close to an iron piece attached to a diaphragm, and a piezoelectric element for vibration detection is directly bonded to the diaphragm.

The oscillation coil and piezoelectric element function stably and are sufficiently reliable at room temperature, but if they are left in conditions exceeding 60°C for a long time, the insulation properties of the coil may deteriorate. This may cause accidents such as the piezoelectric element becoming unstable in function or becoming unusable.

On the other hand, the temperature of the contents of a silo or the like whose level is to be detected sometimes exceeds 80° C., and the temperature inside the silo may rise abnormally due to direct sunlight in the summer.

On the other hand, the structure of the conventional system does not take sufficient consideration of heat, and the main parts of the detector, such as the oscillation coil and the piezoelectric element, face the contents of the silo or the like with the diaphragm in between.1. As a result, these parts are easily affected by the temperature of the contents, and the use of level detectors with conventional structures may have to be restricted to some areas.
Nota.

The present invention eliminates the conventional structural defects under the above-mentioned temperature conditions and provides a highly reliable diaphragm type level detector that always maintains stable function even under considerably high temperatures.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a side sectional schematic view showing a conventional structure.

An iron piece 2 is attached to the center of the diaphragm 1, and an oscillation coil 3 is installed very close to and directly opposite the iron piece 2.

Further, a piezoelectric element 4 for vibration detection is bonded to the diaphragm 1 as close to the center as possible, avoiding the iron piece 2 and the oscillation coil 3.

Since the oscillation coil 3 and the piezoelectric element 4 are in close proximity to the diaphragm 1 or are directly bonded to it, the internal temperature or the temperature of the outer skin of the silo or the like in which the detector is installed, as described above, can be reduced. It is easy to be influenced.

FIG. 2 is a schematic side sectional view of an embodiment showing the structure of the heat-resistant level detector of the present invention.

That is, the diaphragm 1 has a vibration transmission rod 5 erected at right angles to the center thereof, and an oscillation coil 3 is provided in the middle of the vibration transmission rod 5 to surround it. A piezoelectric element 4 is bonded to the tip of the piezoelectric element 5 .

In this way, by newly providing the vibration transmission rod 5 and separating the oscillation coil 3 and piezoelectric element 4 from the diaphragm 1 by an appropriate distance, the silo can be prevented from being directly affected by the temperature from the contents of the silo or the outer shell. It disappears.

Another advantage of this structure is that the piezoelectric element 4, which was previously unable to detect the central part of the diaphragm 1 because it was obstructed by the iron piece 2 and the oscillation coil 3, now detects the vibration of the central part of the diaphragm 1 via the vibration transmission rod 5. Detection accuracy has been further improved.

Next, a heat shield plate 6 made of aluminum foil is placed between the vibration holding housing 7 which holds the vibration plate 1 and contains a part of the vibration transmission rod 5, and the detection part housing 8 which contains the oscillation coil 3, piezoelectric element 4, etc. are sandwiched to prevent heat transfer from the silo side.

Incidentally, heat dissipation fins 9 are provided on the outer peripheral surface of the detection unit housing 8 to dissipate heat from the housing.

As described above, by adding improvements to the structure that take temperature into consideration, the influence of temperature conditions is reduced, and therefore it is possible to provide a highly reliable diaphragm level detector that can be used in a wide range of applications. I can do it.

[Brief explanation of drawings]

FIG. 1 is a side sectional outline view showing a conventional structure, and FIG. 2 is a side sectional outline view of an embodiment showing the structure of the present invention. 1...Diaphragm, 2...Iron piece, 3...
...Oscillation coil, 4...Piezoelectric element, 5...
... Vibration transmission rod, 6... Heat shield plate, 7...
...Diaphragm holding case, 8...Detection part case, 9...
...radiating fin.

Claims (1)

[Scope of utility model registration request] In a diaphragm type level detector, a vibration transmission rod is installed approximately at right angles to the diaphragm, an oscillation coil is surrounded in the middle of the vibration transmission rod, and a piezoelectric element for vibration detection is installed at the end of the vibration transmission rod. The diaphragm and oscillation coil are bonded together, an appropriate distance is provided between the diaphragm and the oscillation coil, a heat shield is sandwiched between them, and heat dissipation fins are provided on the outer surface of the casing where the oscillation coil and piezoelectric element are housed. Heat-resistant structure of the diaphragm type level detector.