A device for determining the liquid level in the tank
(57) Abstract:The inventive device comprises at least three sensing elements 1, the pulse generator 2, the pulse receiver 3, an amplifier 4, an analog-to-digital Converter 5, block 6 calculations, the indicator 7. 1-2-3-4-5-6-7. 2 Il. The invention relates to techniques for measuring non-electrical quantities and can be used to determine the position of the boundary of two immiscible liquids with different dielectric constant of the level and volume of liquids in containers of arbitrary shape.The known device for the measurement of levels and boundaries of the division of environment (ed.St. N 1527505).It is also known a device for measuring the storage level and temperature, liquids and gases of different density in the tank (France N 2624968) containing sensitive element in the form of delay lines, the generator and the receiver.The disadvantages of these devices are the complexity of the scheme, the complexity of manufacturing the sensor element and the insufficient accuracy of measurement.Closest to the proposed device is a device comprising a generator of sinusoidal napapansin in the form of two isolated from each other by wires (coaxial lines). This device works on the principle of radiointerference.The main disadvantage of the device should be attributed primarily to the level measurement only in electrically conductive environments, nonlinearity, complexity of setup and operation, temperature dependence, the advanced setup when you change the physical properties of the liquid.The aim of the invention is to expand the range of measured parameters controlled environments, improving the accuracy and reliability of the device, simplifying the design, manufacture and operation of the entire measurement cycle.For this purpose, the sensor element is designed as two isolated from other conductors connected to the output of the high frequency pulse generator and the input of the receiver, the output of which is connected to the amp via a communication channel connected to a computing device, the output of which is connected to the indicator, which displays data showing the basic parameters of the level boundaries separating and volumes of immiscible liquids with different dielectric properties.To ensure the possibility of measuring the volume levels, sections of immiscible fluids in dynamic conditions (fluctuations in p is g-friend and dispersed by the volume of the measured capacitance.The principle of operation of the device is as follows.Two insulated from each other and from the external environment of the conductor is lowered into a tank of immiscible liquids to full height. These conductors is sent to a high-frequency voltage pulse. The wave resistance (determined by the dielectric parameters of the environment), sent pulse is reflected. The reflected pulses received on the input line, distributed in time. The delay time of the reflected signal relative to the sent is proportional to the distance to the inhomogeneity of the wave resistance (the boundary between two media):
L = 1/2 v t , where L is the distance from the generator output to the border crossing;
v is the velocity distribution of the pulses in the conductors;
t is the time delay of the reflected signal relative to sent.The factor 1/2 takes into account the dual path sent and the reflected signal. The number of reflected pulses is determined by the number of boundaries of media with different dielectric properties.Comparative analysis with the prototype shows that the proposed device differs in that it contains sensitive e is th pulse generator and the input of the receiver, the output of which is connected to the amp via a communication channel connected to a computing device, the output of which is connected to the indicator, which displays the data level, separating and volumes of immiscible liquids with different dielectric properties.And in terms of the fluctuations of the surface of the media device includes at least three sensor elements arranged parallel to each other and dispersed in the volume of the measured capacitance, and will allow you to consider (count) dynamic parameters of the liquid surface. Therefore, this device meets the criterion of "novelty". Comparison of the invention not only prototype, but also with other technical solutions, allows to conclude that the criterion of "substantial differences".In Fig. 1 shows a functional diagram of the device for determining the volume levels and boundaries separating media of Fig.2 - the location in time sent and the reflected pulses, respectively.The device contains sensitive element 1 in the form of two isolated from other conductors, one end of which is connected to the output pulses of the frequency generator 2 and the input of the receiver 3, the other is silical 4, the output of which through the channels 5 connection (analog-to-digital Converter) connected to the computing unit 6, the output of which is connected to the indicator 7. The communication channel is a high speed analog-to-digital Converter, a computation can be implemented on any PC, which includes the analog-to-digital Converter. In detail, the communication channel 5 and block 6, discussed in the book Figurnova C. E. IBM PC user, M.: Finance and statistics, 1991, S. 280.The device operates as follows.To determine the liquid level and the boundary line of the sensitive element 1 is dipped into the tank with controlled environments. The pulse sent by a high-frequency generator 2, while accepted by the receiver 3. The indicator is a momentum Uo(Fig.2). From this pulse count all other coordinates on the indicator 7. The first reflected pulse Ui(Fig.2) shows the time t of pulse passing through the sensitive element to the surface of the liquid in the tank. In scale it will determine the distance from the place of shipment pulse generator output) to the surface of the liquid.The second reflected pulse U determines the time t passes impul which then determines the distance from the generator to the boundary line. The parameter t determines the propagation time of a pulse from the liquid surface to the border of the separation media. In this scale indicates the distance from the liquid surface to the border of the separation media.The computing unit 6 pulses UoU1U2,..., Un(where N is a number and serial number of sections environments starting from the separation of the air-liquid) calculates all parameters storage of liquids: volume, height, number of layers section. The upper level of each of the immiscible liquids is determined by the formula
hi= 1/2v(t) - tiwhere i = 1...N, and its volume according to the formula
vi= F(hi; h) , where F is the calibration function.The total volume is defined as the sum
V=Vi, i=1...N ..The proposed device the greatest effect can give when used in the storage, stationary and especially offline, where you can hit of extraneous fluids.The error count is not more than 0.5%. A DEVICE FOR DETERMINING the LIQUID LEVEL IN the TANK containing the sensing element made in the form of two isolated from other conductors connected to the generator output and the receiver input, the output of which is s, located at different levels and connected to the generator output and the receiver input, and serially connected analog-to-digital Converter and a computing unit that is connected to the input of the indicator, with the input of analog-to-digital Converter connected to the amplifier output, and the generator and the receiver is made of the pulse.
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.