The invention relates to a device for measuring liquid level in open reservoirs, canals, sewage reservoirs and other hydraulic structures. The sensor for low conductivity liquids contains a vertical magnetic circuit, sealed exciting winding, spiral bare electrode, the measuring circuit. The spiral electrode is located on top of the sealed exciting winding and in contact with the liquid. The magnetic core is made in the form of the shielding grating cylinder of the individual ferromagnetic wires, which are closed around the Central part. The Central portion includes a spiral electrode, sealed the exciting coil and the connecting conductor. The measuring circuit is connected to the lower end of the spiral electrode through an insulated conductor passing through the axis of the device. All the elements of the lower end face lattice of the cylinder of the magnetic circuit is isolated from the liquid. The technical result consists in increasing the noise immunity of the sensor. 1 C.p. f-crystals, 3 ill. The invention relates to a device for measuring liquid level in open reservoirs, canals, sewage collectors and other hidrotehnice Erna, the river water to 0,2 - 0,3 Siemens per meter /industrial effluents/. For seawater and technical brines declared the sensor unusable.Known transmitter containing bare spiral current electrode placed close to the potential electrode and the measuring circuit /see application UK 1603793, IPC G 01 F 23/24 from 1981/ the Disadvantages of this device are significant power consumption /tens of watts/ low noise when working near sources of interference industrial frequency of 50 Hz.The closest in technical essence and the achieved result to the claimed technical solution is "Potentiometric sensor" that contains vertically mounted in the receptacle with conductive fluid spiral bare electrode, the lower end of which is connected in series with the Registrar and the potential electrode. The device further comprises exciting the coil /winding/ with a ferromagnetic core, which is connected to a source of alternating voltage, and the coil /coil/ is airtight and installed coaxially inside the spiral electrode /and see.with. The USSR 1627848, IPC G 01 F 23/24, bull. 6, 1991/ This allows susistence replaced by autotransformer. However, in common with similar lack of low immunity - the prototype is preserved. In fact, when the device is at the industrial frequency of 50 Hz potential electrode perceive interference from so-called "stray currents" which is inevitably present near residential and industrial objects /for example, pumping stations/. To avoid interference, it is recommended to use a different operating frequency, but this method greatly complicates the measuring circuit and still does not guarantee full protection.The objective of the invention is to increase the noise immunity of the sensor autotransformer type.The problem is solved by the characteristics specified in paragraph 1 of the claims, and in common with the prototype, such as the vertical magnetic core, sealed exciting winding and located over the top of her bare spiral contact with the liquid electrode and the measuring circuit, and a distinctive, essential features, such as the running of the magnetic circuit from the individual ferromagnetic wires, closing in the space around the Central part of the device and forming a shielding lattice cylindrical surface, and a measuring circuit connected to reglemente lower end face lattice of the cylinder of the magnetic circuit is isolated from the liquid.This improves the noise immunity of the sensor.Especially the performance of the measuring circuit of the device is reflected in paragraph 2 of the claims, namely, the measuring circuit includes a semiconductor diode is included between the lower end of the spiral electrode and one of the wires symmetrical two-wire line connected to the exciting winding of the transmitter, with control line is connected to the network 220 via a step-down transformer, and is proportional to the liquid level potential is removed from capacitor connected between one of the wires of the two-wire line and the earth.The invention is illustrated by the following drawings.In Fig. 1 presents a General view of the device of Fig. 2 shows a longitudinal section of the device along the line a-a of Fig. 3 given the electrical circuit of the device.The transmitter contains the Central part 1 and the surrounding grounded lattice the front of the magnetic core 2. In turn, the Central portion 1 includes a spiral electrode 3, sealed the exciting winding 4 and connecting the insulated wire 5 passing through the axis of the device. In addition, the elements of the lower end of the grating cylinder-magnetic snazy the front of the magnetic core.The transmitter operates as follows.When applying to the exciting winding voltage of industrial frequency (36-50 In for security reasons, staff) of the Central part 1 acts as a step-down transformer with a number of turns at about 10 volts. The spiral electrode 3 contains approximately 100 turns of wire of rectangular cross-section (tape) made of corrosion-resistant material (e.g. stainless steel). The tape is wound with a certain "step", i.e. the gap between the coils. Accordingly, the voltage at the ends of the coiled electrode 3 is 10-12 In (peak value). More voltage is undesirable - a course in fluid significant current causes an increase in consumption of the transmitter power and leads to non-linearity of the scale of the instrument.Because of the spiral electrode 3 is insulated from the earth, it appears a variable capacity depending on the level of the measured liquid. The maximum amplitude value of the potential is equal to half the operating voltage at the ends of the spiral electrode 3 (about 5-6). One of the half-wave potential of the spiral electrode relative to the ground through the diode VD is supplied to a symmetrical two-wire feed line, insulated from the earth.Ministers who on the control center with a capacitor With large capacity, connected to one of the wires of the two-wire power line. Because changes in the liquid level occur relatively slowly, the time constant of the measuring circuit can reach 10 or more, which ensures suppression and periodic impulse noise.Possible electrochemical potentials in the execution of the spiral electrode 3 made of stainless steel do not exceed the 0.05-0.1 V, which is 1-2% of the maximum value of the measured potential.The insulating coating 6 is necessary in order to ensure strictly radial nature of the electric field EWbetween the spiral electrode 3 and lattice grounded cylinder 2. When the axial component of the field at the bottom of the gauge the scale of the instrument will become nonlinear. The same can be said about the tank bottom should have a conductivity much lower than the conductivity of the measured liquid. If the transmitter is in conditions that do not guarantee isolation tank bottom, the bottom end of the grid cylinder 2, you must put a layer insulating film, the diameter of which should exceed the maximum value of the measured level.For operation of the electrical circuit concretelike just to collect the conductors under one sealed input to the Central part 1. In addition, the installation location of the sensor is preferably placed in a protective (e.g., concrete) camera.The technology of assembling sensor.Lattice the front of the magnetic core is assembled from elements of the U-shape with the finished insulation. U-shaped elements are passed through the Central part 1, and then their upper ends bent (not necessarily at right angles and welded together.
Claims1. The sensor for low conductivity liquids, comprising a vertical magnetic circuit, sealed the exciting winding and nestled on top of her bare spiral contact with the liquid electrode and the measuring circuit, wherein the magnetic core is made in the form of the shielding grating cylinder of the individual ferromagnetic wires connected around a Central part comprising a spiral electrode, sealed the exciting coil and the connecting conductor, and a measuring circuit connected to the lower end of the spiral electrode through an insulated conductor passing through the axis of the device, all of the elements of the lower end face lattice of the cylinder of the magnetic circuit is isolated from the liquid.2. The sensor under item 1 that distinguishes the electrode and one of the two wires of the power line, connected to the exciting winding of the transmitter, with control line is connected to the network 220 via a step-down transformer, and is proportional to the liquid level potential is removed from capacitor connected between one of the wires of the two-wire line and the ground.
FIELD: measuring engineering.
SUBSTANCE: device comprises fuel level indicator and rheostat pickup made of an analogue-digital converter with the balance input. The three-position switch is connected with the lever indicator. The device additionally has three resistive dividers, voltage stabilizer, and shunting resistor made of a 0.003-0.006-Om resistor. The rheostat level pickup is mounted inside the fuel tank vertically, and its linear horizontal size at this level is directly proportional to the area of the tank section in the horizontal plane at this level.
EFFECT: expanded functional capabilities.
FIELD: measuring engineering.
SUBSTANCE: method comprises pressing unit reinforced by electrodes with simultaneous forming of insulator between the electrodes. The space that is defined by surfaces of the electrodes is filled with casting plastic mass. The pressure tightness is provided by tightening the insulator with electrodes by means of a nut.
EFFECT: enhanced reliability.
FIELD: the invention refers to measuring technique and may be used for controlling bulk and liquid materials.
SUBSTANCE: the oscillating indicator of a level has a sensible element( a probe) 1 connected with an anchor 2, a driving arrangement 4 in the shape of a coil with a ferromagnetic core and also a sensor 5 of the displacements of the anchor, a drive-pulse generator 6 and an amplifier 7 and a relay block 9 successively connected. The amplifier is spanned with a regulated negative feedback fulfilled in the shape of a resistor 8. The sensor 5 of the displacements of the anchor may be fulfilled in the shape of a coil with a ferromagnetic core. At that the section of the anchor 2 between the coils is fulfilled out of non-magnetic material that prevents electromagnetic connection between the coils providing protection from high frequency oscillations in the system anchor-coil-amplifier.
EFFECT: allows to control the levels of the bulk and liquid materials being present in aggressive mediums, under pressure,( discharge)and at temperature till 200 degrees.
FIELD: instrument engineering.
SUBSTANCE: level meter sensor comprises hollow rigid base with the port in its bottom end, diaphragm, strain gage converter with box, flexible spacer arranged over periphery of the box, and tube whose one end is mounted pressure-tightly in the port of the support and the other end is connected to the space of the box. The diaphragm is made of a rigid material and mounted on the flexible spacer for permitting cooperation with the strain gage converter.
EFFECT: enhanced reliability and simplified structure.
FIELD: the invention refers to the field of instrument making and designed for control of the level of dielectric and current conducting liquids in hydraulic systems (fuel, freezing, accumulative etc) for example the level of oil or cooling agent in transport vehicles.
SUBSTANCE: the liquid level meter has a two-electrode capacitance sensor with an external 10 and interior 11 electrodes electrically connected with an electronic scheme having a stabilized source of power supply, an amplifier, a generator and a trigger. According to the first variant the capacitance sensor is fulfilled in the shape of a coaxial condenser "C". The interior electrode 11 of the sensor is fulfilled tubular and is mounted inside a fluoroplastic probing rod 12. The interior electrode 11 is connected to the input of a phase comparator which is additionally introduced in the scheme and whose output is connected with input of the trigger and the output of the last is provided with a line of delay and has two outputs - direct and inverse connected with a transistor key fulfilled with possibility of fulfillment of an operation "switched on" or "switched off". At that the electronic scheme is fulfilled on a digital integrated microchip. According to the second variant the interior electrode 11 of the coaxial condenser "C" is fulfilled tubular and is additionally provided with a protective shield 22. The shield 22 is fulfilled in the shape of a spiral spring out of bronze and electrically connected with the external electrode - the body 10 of the coaxial condenser "C".
EFFECT: increases sensitiveness and accuracy of measuring of the level of liquid.
6 cl, 4 dwg
FIELD: invention refers to control-measuring technique and is assigned for control and signaling about border of interface between mediums petroleum product-water in installations for purification water from petroleum products or watered petroleum products from water.
SUBSTANCE: sensor has flange, three electrodes with sleeves on their low ends filled with fresh water, moreover two of them are covered with dielectric insulation. Electrodes with sleeves are located inside tube of protective screen and are fastened in flange with aid of stuffing boxes-insulators. Screen in upper part has diaphragm ring with openings along circumference coinciding with openings in screen forming swinging compensator and is fastened to flange with aid of screws. Electrodes of sensor together with sleeves and electronic part form oscillating contour going in resonance at presence in space between electrodes of electric conductive medium (water) with following triggering of executive elements and at presence of water between electrodes of petroleum product resonance of contour stops.
EFFECT: increases reliability of work of sensor.
2 cl, 1 dwg
FIELD: physics, measurement.
SUBSTANCE: invention is related to the field of facilities for automation of different liquids level detection in industrial and household reservoirs, and also for detection of liquids availability and flow in pipelines. Method is based on application of two thermistors that have identical thermal characteristics, and includes heating of one of the thermistors by electric current and its cool-down due to heat transfer to environment, periodic measurement of voltage drop at thermistors, calculation of informative parameter, its comparison with threshold value and making decision on availability or unavailability of liquid at controlled level. At that one of thermistors is periodically heated by short pulses from power supply source. After heating is completed, ratio of non-heated and heated thermistors' voltages are repeatedly measured, and as informative parameter scaled time derivative is calculated by means of specified ratio measurement results array processing. Device for method implementation contains two thermoresistors, which are installed in sensitive element, connected to power supply source and which have temperature resistance coefficients (TRC) of the same sign and identical coefficient of heat emission in gas. Besides, it also contains analog-digital transducer and comparator, reference inlet of which is connected to source of reference signal, and outlet is connected with actuating device. Moreover, device is equipped with pulse switch and serially connected regulator of heating time and synchroniser, and also calculator of scaled derivative. For alarm on liquid flow availability, device is additionally equipped with the second comparator that is connected parallel to the first one, and the second actuating device.
EFFECT: higher efficiency of liquid level detection by increase of device actuation fast-action, reduction of power inputs and expansion of its application field.
13 cl, 3 dwg
FIELD: measuring technology.
SUBSTANCE: invention refers to a measuring device for determination of an amount d(V(z)) of conducting liquid of the conductivity LF by a capacity with vertically (z-direction) varied filling points. There is provided conductivity metre which among others has at least two electrodes extended in a z-direction. The capacitance parametres and/or the metres are ensured so that it/they can be described by means of at least one parametric function, fpi (V(z)) depending on V(z). At least one said parametric functions shall have exponential dependence on V(z). There is also described measuring element, and also method for determination of total amount of flowing liquid d (V).
EFFECT: simplified design of the device and method of measuring conductivity of the conducting liquid.
42 cl, 14 dwg
SUBSTANCE: method if based on measuring capacitance of a double-electrode capacitive liquid level sensor, which in turn in any sequence measures capacitance of the double-electrode capacitive liquid level sensor and capacitance of the same sensor is measured after connecting a capacitive sensor of dielectric properties to it, after which the level h from the upper end of the double-electrode capacitive liquid level sensor is calculated using the formula:
, where h is the level of the liquid in the reservior; CA is capacitance of the double-electrode capacitive liquid level sensor; CB is overall capacitance of the double-electrode capacitive liquid level sensor connected in parallel to the capacitive sensor of dielectric properties; A, B and D are structural parametres of the double-electrode capacitive liquid level sensor and capacitive sensor of dielectric properties. The device for measuring liquid level has a double-electrode capacitive liquid level sensor made in form of a coaxial capacitor, and two cylindrical electrodes. The lower end of the inner electrode of the double-electrode capacitive liquid level sensor is connected to one of the electrodes of the capacitive sensor of dielectric properties through the closing contact of a reed relay, and the lower end of the outer electrode of the double-electrode liquid level sensor is connected to the second electrode of the capacitive sensor of dielectric properties.
EFFECT: high accuracy of measuring the level of different liquids, as well as elimination of measurement errors caused by change in dielectric permittivity of the measured liquid.
2 cl, 1 dwg
SUBSTANCE: sensor for monitoring the level of a liquid has a housing and a printed-circuit board on which there is a substrate having one or two identical film resistors (thermistors) and contact pads (conductors). The printed-circuit board is in form of a plate, one short side of which is rigidly attached to the base of the housing and on the edge of the opposite free side there is a hole whose diameter is 2…4 times larger than the width of the substrate lying over the hole and made from thin heat-insulating material. Each film resistor (thermistor) is in 'point' form with dimensions in the range (0.15…0.5) mm • (0.5…0.5) mm and thickness not more than 0.0005 mm. The boundary surface between each film resistor (thermistor) and contact pads of the substrate (conductors) is in form of broken lines consisting of straight sections.
EFFECT: high mechanical strength of the structure.