DE443985C - Device for the electrical measurement of a liquid level, particularly in the case of flow meters - Google Patents

Description

Device for electrically measuring a liquid level, in particular with flow meters. The invention relates to the electrical transmission of displacement a liquid level, in particular in the case of flow meters with a throttle point and liquid manometer. The shift of the liquid level is in one Vessel made in which either one of the slabs of an electrical Condenser is located, the liquid to be moved is conductive and the second coating forms, or a complete capacitor, with the one to be moved Liquid with a certain dielectric constant forms the dielectric. Man can-also, instead of the liquid moving between the capacitor plates to change the capacity to use solid substances (plates) that act as floats are designed, can be moved so that the capacity is changed.

The measurement takes place in a known manner in that the change the capacity is measured or registered. The capacitors can be made spiral winding plates exist, so that the largest possible capacity in one possible small rooms can be accommodated. That also has the advantage. that z. B. when measuring of steam, gas or liquid quantities using the known differential manometer the zero point is shifted as little as possible with different uses, because the empty space in which the capacitor is located in relation to the other leg can be made as small as possible. You can extend this empty space even further fill in with solid 'media and thus reduce the size.

Processes to be attached, which take place according to linear functions, are simply made by changing the capacitor proportionally — according to the change the liquid level or the respective adjustment of the solid body in relation to measured on the capacitors. In this case, the capacitor must be designed in this way be that the capacity changes proportionally with the liquid level. In the other Case where there is z. B. are quadratic functions, as when measuring Vapor, gas and liquid quantities, the condenser must be shaped so that it is square Changes in liquid level cause linear changes in capacity. You can also think of any other function that also z. B. purely empirical can be determined. Of course, all corrections, such as the above-mentioned change of zero point, be completely compensated.

1vlan can e.g. B. train the capacitor so that one is non-conductive Panels, e.g. B. made of cardboard, Illetallblättchen of the specific shape and glued then covered with a dielectric - or an insulation layer. Has that used Cardboard piece of rectangular shape, so you can put the capacitor in a spiral rolled up Bringing conditions into a room and in this way has very little dead Space, so that only very small zero shifts take place.

Uin to avoid errors in this Meßniethode, the z. B. thereby caused, (lad glue measuring steam condensed water in the upper space of the Condenser, which is not filled by the actual measuring liquid, penetrates, the free space above this liquid becomes with a contemplated liquid Anf; filled.

Some application forms are shown in the drawings. Fig. i: The vessel a represents a container filled with water; dives into the water a 11Tetallrohr c, which on all sides except for the upper connection point with a Protective paint is provided, which represents the dielectric. In your vessel In addition, there is a conductive plate e, which galvanically connects with the water Has. Lines lead from the upper connection point of the pipe c and the plate f and g via an AC power source to an ammeter or recorder of the highest possible resistance. The different levels of the water in the vessel a are reduced or increase the capacitor c, d. This makes the gauges proportional influenced. It is possible to calibrate these measuring instruments accordingly to be used as a remote display device for the water level. As the ones from the meters The current to be absorbed is very low, the conductivity of the water can b can be completely neglected compared to the resistance of the capacitor.

Fig. A shows a gas, steam or water meter. The measuring disk o is located in a tube, from which line p leads to two vessels la and j. These two vessels are connected to one another in a communicating manner by the line i. In the lower part of the vessel h and j there is mercury m, above it in the vessel.la there is condensation water and in the vessel j there is a non-conductive liquid iz, above it also water. The capacitor described above is suspended in the non-conductive liquid. The metal coating of this capacitor just touches the surface of the mercury at the zero point. A differential pressure in the measuring disk o shifts the O_silver downwards in the vessel h and rises accordingly in the vessel j. As a result, a corresponding part of the metal coating on the capacitor, which is protected by an insulating varnish, is immersed in the mercury. This results in an alternating current transfer from the power source to the capacitor, mercury, vessel, and back via measuring and recording devices Z and A to the power source. Depending on how deep the condenser is immersed in the mercury, the capacities forming the condenser are enlarged, and this also changes the display of the measuring apparatus. These deflections of the instruments will be uniform according to the formula: i = e - x - C if the enlargement of the documents on the capacitor increases evenly. However, since with steam, water and gas meters that use a throttle disc, the% length Qit of the liquid to be eroded is proportional to the root value of the pressure differences, the mercury is shifted unevenly in the vessels if the amount to be measured changes evenly will. This fact is taken into account in that the occupancy k of the capacitor is designed according to the square root function, so that despite the uneven displacement of the mercury column, a constant increase in the capacitance of the capacitor is achieved. The previously mentioned root function is therefore converted into a linear one by "using the appropriately designed capacitor".

Fig. 3 shows the rolled-up capacitor in which the various Height levels that each have the same surface area. To get at your jar j To obtain the smallest possible dimensions, the capacitor k is rolled up spirally.

Claims (1)

PATENT CLAIMS: i. Device for electrical measurement of a liquid level, in particular in the case of the liquid manometer of a flow meter, characterized in that that the fluid displacement either directly or indirectly by a a correspondingly shifting float influences the capacitance of a capacitor in such a way that that it is a measure of the displacement, with the shape of the capacitor corresponding the process to be measured is formed. a. Device according to claim i, characterized characterized that the liquid (z. B. mercury) or the float the one Forms plate part of the capacitor. 3. Device according to claim i, characterized in that that the liquid forms the variable dielectric of the capacitor. q .. Device according to claims i to 3, characterized in that the above Liquid existing space with another that does not mix with the former Liquid is filled to prevent ingress of condensation or other conductive Bodies to prevent.