DE1773251A1 - Measuring device for liquid levels - Google Patents

Description

Measuring device for liquid levels

The invention relates to liquid level gauges, and more particularly relates to gauges to display the mean level of a liquid * The requirement for measuring the mean level of a liquid arises from a number of Circumstances, for example when measuring the tide height, one of which is when determining the water level The difficulties encountered are that the sea has V / rushes on its surface.

Today's tide levels have a number of shortcomings. The majority of them are with one Equipped with a float and a measuring tape system with which The result that there is often a significant hysteresis in the mechanism and that it overcomes the disadvantages of the Are subject to equipment that depends on the moving parts required to operate them.

209808/0570

In particular, however, it is an essential feature that tide gauges actuated by swimmers should be placed in a calm well shaft, i.e. in a vertical tube which encloses the swimmer, this tube having a constriction at the lower end in order to attenuate the action of the surface waves * The use of a quiet well shaft has a number of disadvantages, with. In particular, the effective time constant of the measuring device is determined by the shape of the quiet well shaft and the decision to change it at a later point in time raises major problems. If the measuring device is used in an estuary subject to the tides, there is a tendency for fresh water to penetrate into the calm well shaft during low tide, so that with increasing tide height and when salt water begins to penetrate into the well shaft, it contains a mixture of salt and fresh water. This mixture would have a lower average density than the salt water outside the well shaft, which would cause a corresponding increase in the indicated water level. In fast-flowing streams, a positive or negative pressure component can appear at the mouth of the calm well shaft as a result of Pitot or Venturi effects. This mouth can easily be blocked by seaweed or debris thrown into this area, which creates a particular problem in that a tuft of seaweed or other debris can cause a unidirectional characteristic so that it tends to level the wave height at the vertex Therein lie the serious drawbacks of using a silent well. When measuring the tide height, however, it is necessary to have some hydraulic time constant in order to smooth out the changes in the surface waves.

209808/0570

It is an object of the present invention to provide a form of a liquid level heater to create which can be arranged to directly display or record the supplies the mean Begelstandes of a liquid over a period which can be chosen so that it represents a suitable period of time for the particular circumstances of the measurement

According to the invention, a measuring device for liquid levels comprises a plurality of electrical liquid sensors, which are arranged at a distance from each other in the vertical direction, pulse generators, and a plurality by gates controlled by these sensors for the passage of impulses from these impulse generators that do not coincide with an instantaneous repetition frequency determined by the feelers Liquid level corresponds to and means of payment for determining the total number of output pulses these gates for a specified time interval. With this arrangement, the liquid level becomes averaged during the time period of counting determined.

These sensors are preferably arranged in such a way that they provide a coded digital output, which is representative of the instant liquid level and it is a number of ports which correspond to the number of bits in this digital output, each port corresponding to one bit and, in accordance with the size of this bit, the injection of pulses from an associated one Pulse source controls, whereby the pulse sources assigned to the different gates have repetition frequencies proportional to the display value of the bit corresponding to that gate.

209808/0570

A binary digital system is used particularly advantageously and in a preferred embodiment a measuring device for liquid level * comprises a plurality of electrical liquid sensors which are arranged in a vertical direction at a distance from one another in such a way that they provide an output signal in binary digital form which represents the number this sensor ^is representative are i Le below the surface level of the liquid, wherein a Hehrzahl of aND gates corresponds to the number of binary digits, wherein means are provided for feeding ies binary Ausgangssignas to a first input of each of these Uend-gates, and means in order to feed impulse signals that do not coincide into the other input of the UITD gates with a frequency that for each gate is proportional to the display value of the binary digit fed into the first kingang of this gate, i.e. the frequencies form a geometric series with base 2, with finally Counting center l are provided to determine the total number of output pulses from all AND gates during a predetermined time interval. According to a particularly advantageous embodiment, the sensors are capacitive sensing elements and therefore the unit intended for use in the liquid can comprise a probe which comprises a series of capacitor electrodes arranged uniformly at a distance from one another in the vertical direction. A digital measuring device equipped with capacitors for fluid levels, which is suitable for this purpose and which: provides an electrical output in binary, digital form, is described in the, {, German patent hitbIlütrn ^ /T1498427.1.

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209808/0570

The pulse signals of the various, different frequencies are advantageously selected an oscillator with a frequency divider chain to output frequencies which are consecutive divided by the factor 2 are »These pulse signals and the binary, digital representation of the liquid level can, as described above, fed into the AND gates and the outputs from all different AND gates can then go through an OR gate are fed to this counting means, which advantageously a decimal counter or can be a recording device

Although binary code has been referred to above, in general terms any root can be applied provided that an appropriate system of non-coincident pulses is provided.

The duration of the counting by the counting means can be according to the distance between the sensing elements and with the selected frequencies for the pulse signals are selected, ead that the counting means a direct display in delivers any desired units such as feet, meters, etc. Among other things, the required duration of the Counting depends on the frequency of the signal, if an oscillator with a frequency divider chain, is used as described above, this oscillator can also be used to also dia To control the duration of the count, so that the display does not change the frequency of the oscillations being affected. For this purpose, the Bau «! · Der Counting can be counted out by another counter, which directly the periods of the ossillator aaegoxig of the exit from one of the frequenz bellet »

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The following will be an embodiment of the invention described with reference to the drawing, which shows a schematic representation of a tide level.

The tide level has a probe, which is shown schematically at 10, with a series of spaced electrodes 11 which, according to a typical example, have a distance of 5 ca from one another. The length of the probe is such that its lowest part is always immersed in the sea at the lowest water level and the upper part always remains above the waves at the highest water level. The water level is therefore always between the ends of the probe. The electrodes are connected to a drive and detection unit, which is shown schematically at 12 and which supplies output pulses on an Ap ^ m of lines 13, which in binary, digital form are representative of the instantaneous matter of the number of sensor electrodes, which are located between the water surface and the lower end of the probe · A suitable drive and determination arrangement is described in the aforementioned German patent application // £ Λ4 9S 427.1 11 '>. This binary coded signal will change when the water level changes, but the effective time constant can be chosen in the order of magnitude of milliseconds and for the oriiogonde purpose the binary output signal can be repiSsentatlv for the instantaneous water level »The binary output is available in parallel foxfü and these digital signals are transmitted on üiüo fieiho from liND-Toran 14, 15, 16 etc., whereby the most characteristic digital signal is transmitted to the gate 14, which in its code 1; next signal to gate V) etc.

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The output from the oscillator 20 is transmitted to a binary rope chain consisting of the ropes 21, 22, 23, etc., each dividing by a factor of 2, and the ropes being arranged to send non-coincident pulses on a series of output lines 31 «32, 33 and so on. These mismatched pulses can easily be obtained by arranging so that each rope operator alternately provides signals to an output circuit and to the next rope operator in the chain. The oscillator 20 must therefore deliver signals with twice the required half-frequency. For example, it is assumed that the oscillator 20 has an output of 200 pulses per second, so that the rope 21 provides an output of 100 pulses per second, the rope 22 an output of 50 pulses per customer, etc. The output from the rope 21 is on the AND gate 14 is transmitted, the output of the rope worker to the AND gate 15, etc. By using a dividing chain 21, 22, 23 etc., all the different impulses from the rope workers in the chain do not coincide and thus the different UHD- Sore 14, 15, etc. provide a Rei-he not coincident ■ output pulses whose number will depend in each period thereof which are UHD Sore open and which are closed. These output pulses from the UBD gates are fed through an OR sensor 30 to a decimal digital counter 41 which counts the pulses during a time period which is determined by an interval timer 42.

In the special example shown in the drawing, nine rope steps 21, 22, etc. provided and nine tJHD-Sore 14, I5 etc.

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209808/0570 B ^ ^jK ~ '

If one assumes that the distance between the sensor electrodes is 3 cm, one recognizes that, only fall the bottom electrode is immersed in the liquid, an output pulse from dom OR gate 30 in a Time period of 2.56 seconds is obtained. If more than one of the electrodes is immersed in the liquid, the number of electrodes in this period will be received output pulses match the number of immersed electrodes »If the Time interval counter is therefore arranged in such a way that it causes a count over eir.e lOrio & ß of 256 seconds, For example, the water level would be 12 m result in a count of 40,000 on the counter. It can be seen that the counter at the end of its counting period shows the average pulse frequency over the entire period. The mean pulse frequency is direct proportional to the binary number that represents the mean level. The ones on the counter at the end The number shown in the counting period is the average level during the counting period.

It is immediately apparent that the time constant for the counting period can be chosen to be any Assumes value which is appropriate to the given circumstances. The frequency of the oscillator 20 can be so be set so that a direct numerical display of the level height is obtained in suitable units, regardless of the time period used for counting and regardless of the distance between the sensor electrodes. It is therefore easily possible, for example, to switch the display from feet to meters by adding the factor 0.3048, either in the counting period or in the oscillator frequency, without affecting the construction the probe is changed. The interval timer 42 is, particularly advantageously, a further counter which Pulses from the oscillator 20 counts. The duration of the pp.riodo can be set as required

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is by setting the total which this additional counter counts. By using a further counter ic of this type, one obtains the advantage that small changes in the frequency of the oscillator 20 do not affect the measurement of the liquid level because they are caused by the change in the.? Compensation period are compensated,

It should normally be possible to read the mean level of the level in an order of magnitude which is better than the error deviation resulting from the placement of the sensors and, by taking the average of the fluctuating levels generated by the action of the solid, an interpolation can actually be carried out between the discrete levels of the sensors. In the particular embodiment described, the average level can be displayed on the order of 3 na, although the sensors are 3 cm apart.This technique for obtaining a level measurement with a more accurate value than the discrete distribution of the sensors can in more general form can be used for measuring liquid levels, even in the case of a system in which the water level is normally stationary, by mechanically vibrating the probe in a vertical direction, or by using an artificially generated vortex of the surface level and averages over a period of time. This makes it possible to achieve this actually greater accuracy.

Where a stabilized frequency main electrical line is available, it is more convenient to use this power source instead of the oscillator 20.

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The main line can then also be used, to provide a timer so that the measurement time can be recorded as well as the actual time Size.

With a tide marker for harbors or entrances Frequently faster fluctuations of considerable amplitude are superimposed on the tidal fluctuations, which by the characteristic water movement of the harbor or the entrance is caused, i.e. by the Circulation movement of the water in the harbor or the entrance, which depends, for example, on the wind. The period of such a movement of water is usually known for each particular port, and it can be at the Measurement of the level height should be preferred to the duration the Heßperlode, during which the count is carried out is to adjust as close as possible to the periodic time of this water movement, so that this fluctuation almost completely extracted from the recording.

The output of the counter 41 can be read visually or, as indicated at 43, can be any as appropriate Medium can be recorded, such as a magnetic tape, a punched tape or punched cards or it can be via over a line or wirelessly to a remote radio.

Expectations :

209808/0570 ^BAD

Claims (1)

Claims 1. Measuring device for iriür; 3iglreitEstands, characterized by. a reference to electrical fluids (1'i), through impulse sensors (20, 21, 22, 23) through a number of gates controlled by these sensors (14, 15, 16) and not combined 'ef fender impulses from these impulse generators with an instantaneous repetition frequency, which corresponds to the liquid level determined by the sensors, and by counting means (4-1) for determining the total number of Aunga'aga impulses from these gates during a predetermined time interval. 2. Measuring device according to claim 1, characterized in that these sensors (11) are arranged in such a way that they supply a coded digital output signal which is representative of the current liquid level, and that a number of gates (14-, 15, 16) which correspond to the number of bits in this digital output signal, each port corresponding to a bit and, in accordance with the size of this bit , controls the injection of pulses from an associated pulse source (21, 22, 25), the pulse source function being the various gates are connected itfelehe WiederholungshSnfigkeiten have "Good marriage AEEN Anaeigegrößen the corresponding outside Blis are proportional. • I 3. Measuring device for liquid _levels marked f by a plurality of electric fluid sensors (11) which are arranged vertically spaced from each other / and so constructed that it has a deliver in bluetooth digital form, 209808/0570 17 7 3 2 IS 1 where] olio "i for the number of servant filors repränoni.Gtiv int, we3ch <3." J <; L mriii! ¹ · clem 3 ^D <3 (; el dor P3ür »yißkeltrujhoi \ i \ uh: lKi boiindon, that ijj.i;« Hohr «« »! * ¹ from UHU-'Poren ('Wl, Ii; .. 16) Jhifcnli .. "iJJiiuM;:. · ¹ ]). I _i ;; .5 i; r:.? Nt: / speaks,» aß lVii; U: X K.1 '■) /·.,α :. i.'mif, da- · biurroi! AuHßan.gKHißna.ie: in a »}} 07'ijtoa JIJji7i? .i] {j nines, -jodon dinner TJHJV-Toro vovftp.nvlwn ßiud, Howjο I1J1; i; ol aiii 'Eiuaptäinunp, "inen not zuiimrnontroffendou 3npulMHißiia3on in d <m nndoron Ein (; an (j dionor UHl) -Torο HH oiuor fiir Jodof? Tor den" Κβηη7, ο1 "1ιη \ ιο ($ 3. \; ιο ιο ($ 3. \; ιο (. · 3 .Ml; «·« KliJgnnß djoocis To3 '«n zugefüluton'binäroxi JM ci tr; J) J ¹ O]) Oi ¹ I, i ona3on Proqucnz and duroh CountmH i <j] (^ 1) 2iu' ] l :: ^v iü1i <;] iniß dor (ieimmV'Zuhl von
now «13« υ UiiD-Toi'on during oinon j'Hi; nndi Ληπ]). ηκ; Ιι 3, thereby d1o juuii'nr.ircJ'o HoprJl / ujntiaiiz. the Ια & αΊϊΐ bint? .v 1.:;1. ^ oväi. 3ΐπ <· -] ι Ληπ]) 3 · ιΐ (: 1ι ^; ί, in that din 3Ηψιΐ.ΊΐΗ ^ κηα3α dos ^ verRolilodoinin untornchiodlichon jV'C! (Jufi «7.« n «uo (ijnem oscillator (20) renews been, wooi (line. IfYo <iuon "toi3orli" tto (21, 22, 23) Prequonr.en l., wo3 <i1hi aufelnandoriolgond by don divioor (2) i "Ind. 6. Ilttßßariit according to Anspsnich ¹ J ₁ daduj'oh gekennzolchnot, dniJ dor O.izjl.lnt; or (20) to "3t;ou" run the time period dor the counting bonutBt iflt. 7. Uiih ^ p.rät according to Annpimch G, characterized in that a further counter is provided for controlling the counting time, which directly counts the periods of the oscillator output G or the output from one or more of the parts. 8. Hearing aid nnoli ninora dei * Annpi-üche 3 to 7 »characterized in that the extension of all AND gates (1 ^ 4, 15» through an ODEH gate to these sensory means (^ 1) has been filled. 209808/0570 BAD ORiGiNAL 9. Measuring device according to one of the preceding claims, characterized in that the counting means comprises a decimal counter. 10 »Measuring device according to one of claims 1 to 8, characterized in that this - counting meansX a Include clocking device (4-5), 11. Measuring device according to one of the preceding claims, characterized in that the sensor (11) is capacitive Feel learn to be ante. 12, measuring device according to one of the preceding claims, characterized in that the sensors are mounted on a probe and in that means are provided for the To subject the probe to a mechanical vibration movement in the vertical direction Measuring device according to one of the preceding. Claims, characterized in that means are present to transfer vortex motions to the surface level of the liquid * Blank page