CS262067B1 - Capacity system for hydrostatic levelling - Google Patents

Abstract

Capacitive system, hydraulic leveling is formed by the construction of sensing capacitive sensors, in which the level ratio changes the total length of the sensor, the sensors being electrically connected by outputs with measuring inputs exchange. Capacitive sensors mounted on leveled object are connected by pipeline with expansion vessel, with comparator sensor and with standard sensor, which are placed on a solid foundation. Automatic the operation of the device is given by the measuring program exchange.

Description

The invention solves the concept of a new capacitive hydrostatic leveling system with electrical sensors utilizing the dielectric properties of the hydraulic medium to automatically determine deviations from the leveling plane for geodetic purposes.

Sensors with electrical signal transmission used for leveling work were mainly applied in pairs as terminal devices. The systems used for hydrostatic leveling most often used types of sensors with the methods of reading on the scale and by means of electrode contact with the surface. It is currently known and used measurement technology. These systems, however, usually worked on simple hydraulic circuits consisting of practically a pair of sensors. The creation of circuits with a large number of measuring sensors brought disproportionately complicated problems, which were solved only by the system of automatic hydrostatic leveling, where the sensors were used on the principle of float transducer of level position to electrical quantity of voltage or current. These sensors are sensitive to relative height changes and are able to distinguish differences in level movements up to the order of 10-3 _mm . however, the exact conversion to length measures is given by setting the gain on each sensor individually. The practical use of the system was made possible by the introduction of the so-called standard of hydrostatic leveling, where it was possible to uniformly determine the gain of each position sensor.

The system has been practically tested, but places considerable demands on the mechanical design of the sensor, since the float part of the sensor is prone to slight scrubbing due to friction on the walls.

The above-mentioned drawbacks are eliminated according to the invention by replacing the float sensors monitoring the level of the hydraulic medium with the adjusted capacitive sensors, the essence of the invention of the modification of the capacitive leveling system is that all sensing capacitive sensors equipped with transmitters of measured electrical values of the whole system are each capacitive sensor forms a capacitor with its surface electrode and internal electrode, the dielectric of which is partly a hydraulic medium varying with the level of the hydraulic medium and the remainder above the surface is air, the pipeline distributing the hydraulic medium from the buffer tank and to the same pressure as in the expansion tank.

An exemplary configuration of a capacitive hydrostatic leveling system is shown in the accompanying drawings, in which Fig. 1 is an overall configuration and Fig. 2 is an axial section of a sensing capacitance sensor.

The device is shown in Fig. 1 and consists in arranging and connecting a set of capacitive sensors with sensors 1 and level 2 in a hydrostatic capacitive leveling system. The capacitive sensor itself consists of two co-axial cylindrical electrodes 3, 4, where the surface electrode 3 forms the sensor container 1 and in which the inner electrode 4 is insulated. The space between the two electrodes 3, 4 fills the hydraulic medium and the rest air. The capacitor formed in this way is connected to the electronic evaluation part 5 of the sensors with sensors 1, which is connected to one of the input channels 7 by the microprocessor controlled measuring panel 8 with its output line 6. All capacitive sensors with sensors 1 mounted on monitored points are connected to The fluid level 2 is provided either by or without an additional air distribution system 15, provided the same atmospheric pressure is maintained at the same pressure. all sensors 1, 12, 13 and buffer tank 11.

The principle of operation of the whole device is based on the change of capacity of each capacitive sensor 5 by sensors 1, which is dependent on the level 2 of the hydraulic medium according to Fig. 2. Electrodes 3, 4 form a cylindrical capacitor whose capacity corresponds to the relation πεο (slil + εζΐζ), in

Π [F; F / m, m, F] where denotes:

(H + I2J = constant, εο - vacuum dielectric constant, ει - air dielectric constant, ε: · - hydraulic medium dielectric constant, - cylindrical condenser length (const.j,

1’2 / ri - electrode radii 4, 3 (bones) a

K - parasitic capacities (const.

In the case of the sensor we use changes of dielectric constant ε depending on the immersion length of electrodes 3, 4, where for air is ε pro S 1 and for water ε2 and 80. The resulting capacity then appears as part of capacitors of two capacitors and different dielectric, where lengths I1 and I2.

After measuring the capacitor capacitance, the signal is adjusted in the amplifier 5 and the output variable 6 is connected to the control panel 8. Similarly, all the sensors 1, 12, 13 of the system are connected to the control panel 8, thereby creating a new hydrostatic leveling system. The processing of the measured values by the microcomputer of the control panel 8 remains practically the same as in the hydrostatic leveling system with float sensors. The range of the system is given by the number of leveling points 9 of the secured object and is limited by the number of inputs 7 of the control panel

8.

The advantage of the new hyd262067 capacity system

S rostatic leveling compared to the previous one is to eliminate unreliability when scrubbing float sensors and secondly to extend the measuring range of the leveling system. The accuracy of the system in comparison with the float system remains comparable in the given measuring range (ie up to 8 mm), the accuracy decreases proportionally with the increasing range. Further advantages can be seen in simpler production of sensors than float sensors, and in particular in reduced demands on assembly accuracy, since the sensors do not need to be balanced or mechanically adjusted during assembly.

The capacitive system of hydrostatic leveling represents another system of leveling not used so far, designed for geodetic work in monitoring deformation of machinery and constructions, which should be supplemented in future in selected key constructions with continuously monitored building foundations such as nuclear reactors, turbine sets, compression stations gas pipelines, etc. Some applications can also be used to monitor recent Earth movements.

Claims (1)

Subject A capacitive hydrostatic leveling system, consisting of a set of capacitive sensors with surface electrodes immersed in a hydraulic medium, characterized in that all sensing capacitive sensors (1j) are connected by their output (6) to the inputs (7) of the control panel (8). a sensor (1), the dielectric of which is partly a hydraulic medium and partly an air, the ratio between these mediums varying depending on the change in the measured height (2), the capacitive sensors (1) being connected by one pipe (10) to the buffer tank (11) ) and a second pipe (15) with a space above the surface.