DE2625560A1 - Measurement of mass flow of solids in conveyor tracks - using conversion into AC voltage of variation in deflection of probe - Google Patents

Abstract

The a.c. voltage obtained from the measured in the deflection of the probe is processed into a measured value analogous to the mass flow of solids. An elastically mounted probe projecting into the conveying track is connected to a converter which has connected to it on the output side a measuring instrument to indicate the alternating current voltage. A piezoelectric converter, acceleration pick-up, alternating-current voltmeter or sound-level meter can be used. A steel pin can be used as the probe.

Description

FRIED, KRuPP SOCIETY WITH

LIMITED LIABILITY in Essen Method and Apparatus for Measurement of the solids mass flow in solids ~ conveyor lines The invention relates to a method and a device for measuring the mass flow of solids in solids " Conveyor routes * where eligible, solid goods are given.

if transported by a means of transport. For monitoring and control of the solid transport, it is necessary * that the solid mass flow (Dimension: mass / time unit) determined in the conveyor line with as little delay as possible will.

In a known method of the type mentioned, the solid mass flow m = dm = #. v. A dt 2 = density of the conveyed material v = mean solids velocity ~ A = cross-section of the conveyor line, the product A. by absorption of radioactive Radiation and the mean solids velocity v by an ultrasonic method or an optical method is determined. The two measured values are then carried out an arithmetic circuit linked together, in this known method it is disadvantageous that, for security reasons, considerable expenditure on protection radioactive radiation required SLnd.

The invention has for its object to drive a Vert and a To create a device for measuring the solids mass flow that is not expensive Need protective devices that work quickly and reliably and with which in particular the determination of solid mass flows with solids concentrations is possible This object is achieved according to the invention in that the Fluctuation in the deflection of a probe protruding into the conveyor line into an alternating voltage and then converted to a measured value analogous to the solid mass flow rate is processed o The device for carrying out the method is according to the invention in such a way that an * elastically mounted one protruding into the conveyor line The probe is connected to a transducer which is a measuring instrument for displaying the alternating voltage is downstream. It is particularly advantageous if the designed according to the invention Device as a transducer a piezoelectric transducer, preferably an accelerometer, and as a measuring instrument a liechselvoltage voltmeter, preferably a sound level meter In a further embodiment of the invention it is provided that in the device between the transducer and the measuring instrument a free space.

quenzfilter, preferably a third octave filter, is arranged.

In addition, it is provided according to the invention that a steel pin is used as the probe is used.

With the invention it is achieved in an advantageous manner that the solid mass flow of mechanically, pneumatically or gravitationally conveyed solids with a simple Device can be measured practically without delay can, with both closed and unilateral conveying lines as conveying lines open conveyor troughs can be used. The invention can also be used in the conveyor lines which have a high solids concentration can be used with particularly good success exhibit.

Two embodiments of the subject matter of the invention are shown in the drawing and are explained in more detail below, They show: Figo 1 device for measuring the solid mass flow in a conveying line Figo 2 arrangement the probe of the device according to the invention in a conveyor trough.

Figure 1 shows a conveyor line designed as a conveyor line 1, in which there is a probe 2, which is preferably designed as a steel pin. The probe 2 is resiliently mounted in the wall 3 of the delivery line 1 in that it is embedded in an intermediate piece 4 made of elastic material If the delivery line 1 consists of an elastic material, the intermediate piece 4 is not ore required. The probe 2 should extend over the central axis a of the delivery line 1 extend out, it is advantageous if the probe 2 almost the whole Internal diameter Di of the delivery line 1 assumes. In any case, however, there must be a distance 5 between the probe tip 5 and the inner wall 6 of the conveyor line 1 present so that the measuring results are not caused by contact between probe 2 and the inner wall 6 are affected.

At the end of the probe 2 facing away from the delivery line 1, the as Accelerometer 7 trained piezoelectric transducers arranged0 next to the advantageously working piezoelectric transducers can also be inductive or capacitive transducers are used and it is also possible to incorporate the transducer into the To install probe 2. The accelerometer 7 is followed by a unit 11, consisting of a frequency filter 9, a sound level meter 8 and an integrator 10 There is a display device or a registration device attached to this unit 11 12 connected0 The sound level meter 8 is based on the principle of the alternating voltage voltmeter working measuring device.

Some of the solid particles p transported in the conveying line 1 will bump against the probe 2. The individual bumps take effect in the event of a rapid series of bumps like a force which deflects the probe 2 from its zero position and during a certain unit of time in its size fluctuates The caused by the fluctuation and the deflection made possible by the elastic probe support is during a certain time unit is not constant and therefore calls a time-variable in the converter AC voltage u (t), which can be displayed with a suitable measuring instrument is brought.

The alternating voltage u (t) is made up of vibrations of different Frequency together, With the frequency filter 9 it is possible to select from the frequency spectrum of the alternating voltage u (t) to select the frequency range in which the change of the solid mass flow m i the greatest possible change in the alternating voltage u (t) causes 0 The frequency filter 9 can also be used in an advantageous manner the low frequency ones Vibrations caused by mechanical shocks caused by the device, filter out.

If the conveyor line is designed as a conveyor trough 15, it has It has proven advantageous that the probe 2 'is attached to two leaf springs 13-14 * is arranged on the wall of the conveyor trough 15 perpendicular to the conveying direction are. It is also useful if the accelerometer 7 'between the leaf springs 13, 14 is attached to the probe 2 '. In FIG Arrangement shown.

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Claims (1)

A n s p r ii c h e: 1 method for measuring the solid mass flow rate in solids conveying lines, characterized in that the fluctuation of the deflection converted into an alternating voltage by a probe protruding into the conveying path and then processed to a measured value analogous to the solid mass flow will. 2. Apparatus for performing the method according to claim 1, characterized characterized in that one in the conveyor line (1 15) protruding, elastically ge stored probe (2, 2 ') is connected to a transducer (7, 7') to which a measuring instrument (8) is connected downstream to display the alternating voltage 0 30 device according to claim 2 * characterized in that it has a piezoelectric transducer 4. Device according to claim 3, characterized in that it has an acceleration sensor having 5. Device according to claims 2 to 4, characterized in that it has an AC voltmeter as the measuring instrument (8). 6. Apparatus according to claim 5, characterized in that it has a Has sound level meter. 7. Device according to claims 2 to 6, characterized that between transducer (7, 7 ') and measuring instrument (8j a frequency filter (9), preferably a third-octave filter, is arranged. The device according to the claims 2 to 7, characterized in that a steel pin is used as the probe (2).