GB1567485A

GB1567485A - Analysis of flowable material

Info

Publication number: GB1567485A
Application number: GB5421076A
Authority: GB
Original assignee: K+S AG
Current assignee: K+S AG
Priority date: 1977-01-05
Filing date: 1977-01-05
Publication date: 1980-05-14

Description

(54) UHF ANALYSIS ()F FL()WAHLE MATERIAl (71) We, KALI UND SALZ A(j, a Germany company ot 35()() Kasscl, Postfach 102()2'9, West Germany, do hereby declare the invention tor which we pray that a patent may be granted to us and the method by which it is to be particularly described in and by the following statement: The invention relates to methods and apparatus for analysing soluble and particulate flowahle material. Particularly it relates to such methods and apparatus which can be automatically controlled.

Automatic metering and weighing devices are known in which the material to be analysed is introduccd by hand and mitered by means of a metering spout. the latter being automatically disconnected when the desired amount of the sample has been taken. The excess material must be removed either by discharging the metering spout into a separate vessel or by hand. These prior deviccs require operating personnel.

The present invention is directed at the problem of automating the taking of samples from flows of material such as ground. crystallised. granulated. soluble substances; weighing a portion of each sample; and determining the substances contained therein, in such a manner that no operating personnel are now required.

According to the invention, a method of analysing a soluble and particulate flowable material comprises taking a sample from a flow of the material using an automatic sampler; feeding the sample to a metering device having a discharge spout, the device being movable between first and second positions of the spout; discharging the sample with the spout in its first position into a dissolving vessel supported on a weighing machine: halting the discharge and moving the spout to its second position upon a predetermined weight having been discharged; discharging any excess amount of the material from the spout in its second position; adding a predetermined amount of solvent to the material in the dissolving vessel and stirring the contents of the vessel to form a solution therein: and feeding the solution so formed to a receiver from which a portion of the solution is extracted for the automatic determination of the components of the flowable material, the steps of the method being determined by control elements linked to the respective operative components. The method may then be repeated for subsequent samples.

Apparatus for carrying out the method of the invention comprises an automatic sampler for extracting a sample from a said flowing material: a metering device for receiving material from the sampler, the device having a discharge spout movable between first and second positions; a vessel supported on a weighing machine and located beneath the end of the spout when in its first position, means connected between the weighing machine and the metering device for halting discharge from the spout and moving same to its second position upon a predetermined amount of material being delivered to the vessel; means for initiating discharge of material from the spout in its second position to dispose of an excess amount thereof; an automatic burette for adding a predetermined amount of solvent to the vessel; means for stirring a mixture in the vessel to form a solution; and a valve for passing a specified quantity of a solution of the material and solvent to a receiver for analysis, the apparatus including control elements linked to the respective components to determine the operation thereof.

The metering spout will normally be vibrated during discharge of material therefrom and such vibration can be controlled to accelerate or decellerate the rate of discharge so that the discharge is accurately monitored. The stirring of the mixture of material and solvent in the dissolving vessel is also preferably controlled in accordance with the solubility of the material being analysed. Both the stirring time and speed, for example in the range 5000 to 20,000 r.p.m., can be varied.

Typical materials suitable for analysis by the method of the invention are crude potassium salts, technical crystalline products of KC1, K2SO4, MgSO4.H2O, NaC1, and also granulated leonite.

In preferred embodiments of the invention the solution formed in the dissolving vessel is analyzed by an electronic analogue computer which determines the concentration of the dissolved material in the solvent.

In preferred apparatus for carrying out the process of the invention, the metering spout is mounted for rotation between its first and second positions, such rotation being thereto by a motor and the motor is controlled by means of light barriers which locate the spout in its first and second positions. The dissolving vessel is normally open and preferably consists of a cylindrical tube, stands on the weighing device, and in its interior has a floor which is inclined in relation to an outlet connection to enable the solution to be completely emptied therefrom.

The invention will now be described by way of example and with reference to the accompanying drawing which schematically illustrates both the method and the apparatus of the invention.

With the aid of an automatic sampler 20 and a sample divider 21 a sample is taken from a flow of material consisting of ground crude potassium salt of the following approximate composition: 14.9% KC1, 64.0% NaC1, 17.0% MgSO4.H.O, 2.6% MgC1.. 1.5% CaS04 the sieve fraction up to 1 mm being used - and is fed by way of a hopper 1 to a metering spout 2 which meters about 2 g of the crude salt into the dissolving vessel 3. The weighing device 4 on which the dissolving vessel stands determines the exact weight and feeds the weight to an electronic analogue computer 18. The metering spout 2 is mounted for rotation on a motor 22.When the desired amount of material which is determined by control element 17, has been delivered to the dissolving vessel 3. discharge from the spout 2 is halted and the motor 22 operated to move the spout to its second position shown in dotted outline at 7. Any excess material is there discharged. The spout is preferably vibrated to facilitate discharge of material in either of its positions. Vibration of the spout 2 is effected through a control element 5. The motor is operated in response to signals received from light barriers 24a-a - 24a-n which provide signals indicating the position of the spout to the control elements 15 and 6.

200 cc of water are then added bv means of an automatic burette 9 and the dissolving operation is carried out with string. The operation of the burette 9 is controlled by a control element 8 which monitors the amount of matter in the dissolving vessel 3 by a signal from the weighing device 4. After a stirring time of 3 minutes at 10000 rpm under the control of element 10, the solution is fed by way of the automatic valve 12 controlled by element 11 to the sample receiver 13. The bottom 23 of the vessel 3 is inclined towards its outlet to enable complete emptying. From the sample receiver 13 the solution is sucked into a flame photometer 19 according to DT-PS 22 12 490.The extinction value thereby determined is likewise fed to the computer, which from the initial weight, amount of water. and extinction determines and prints out the potassium content of the crude salt. After use, the sample receiver can be emptied through valve 14.

With various crude potassium salts the following values were obtained.

Time Initial Amount of Gravimetric Flame photometric amount solvent KoO content KO content g cc < Xc 15.00 2.1 200 9.4 9.5 15.30 2.0 200 9.6 9.4 16.00 2.2 200 9.4 9.4 16.30 1.9 200 9.5 9.7 17.00 2.2 200 9.3 9.1 Since because of the filling operation, the weighing operation fluctuates around a determined value of for example 2 g. the actual amount must be fed to an electronic integral computer which stores the exact weight of this amount. The exact amounts of solvent and water are also fed to the electronic integral computer. From the weighted amounts of the substance. the amount of solvent. and the analvtical value. the computer calculates the concentration of the dissolved substance in the amount of solvent. The computer is therefore a component of the entire process for a completely automatically operating procedure.

Claims

WHAT WE CLAIM IS:

1. A method of analysing a soluble and particulate flowable material comprising taking a sample from a flow of the material using an automatic sampler; feeding the sample to a metering device having a discharge spout, the device being movable between first and second positions of the spout; discharging the sample with the spout in its first position into a dissolving vessel supported on a weighing machine: halting the discharge and moving the spout to its second position upon a predetermined weight having been discharged; discharging any excess amount of the material from the spout in its second position; adding a predetermined amount of solvent to the material in the dissolving vessel and stirring the contents of the vessel to form a solution therein: and feeding the solution so formed to a receiver from which a portion of the solution is extracted for the automatic determination of the components of the flowable material, the steps of the method being determined by control elements linked to the respective operative components.

2. A method according to Claim 1 wherein the spout is vibrated during discharge of material therefrom.

3. A method according to Claim 2 wherein the vibration of the spout is controlled to vary the rate of discharge.

4. A method according to any preceding Claim wherein the stirring of the mixture of material and solvent in the dissolving vessel is controlled in accordance with the solubility of the material being analysed.

5. A method according to any preceding Claim wherein the material to be analysed is selected from crude potassium salts; technical crystallised products from one of KC1, K2SO4, MgSO4.H20, and NaC1; and granulated leonite.

6. A method according to any preceding Claim wherein the solution is analyzed by an electronic analogue computer which determines the concentration of the dissolved material in the solvent.

7. Methods of analysing soluble and particulate flowable material according to Claim 1 and substantially as herein described.

8. Apparatus for carrying out a method according to any preceding Claim comprising an automatic sampler for extracting a sample from a said flowing material; a metering device for receiving material from the sampler, the device having a discharge spout movable between first and second positions; a vessel supported on a weighing machine and located beneath the end of the spout when in its first position, means connected between the weighing machine and the metering device for halting discharge from the spout and moving same to its second position upon a predetermined amount of material being delivered to the vessel; means for initiating discharge of material from the spout in its second position to dispose of an excess amount thereof; an automatic burette for adding a predetermined amount of solvent to the vessel; means for stirring a mixture in the vessel to form a solution; and a valve for passing a specified quantity of a solution of the material and solvent to a receiver for analysis, the apparatus including control elements linked to the respective components to determine the operation thereof.

9. Apparatus according to Claim 8 including a motor for moving the discharge spout between its first and second positions; and light barriers linked to the motor for halting such movement when the spout is in one of its said positions.

10. Apparatus according to Claim 8 or Claim 9 wherein the dissolving vessel is cylindrical and has an open top, the floor thereof being inclined with respect to an outlet at the base thereof enabling complete emptying.

11. Apparatus for analysing a soluble and particulate flowable material substantially as described herein with reference to and as illustrated by the accompanying drawing.