US3442137A

US3442137A - Method and means for sampling pulverulent material

Info

Publication number: US3442137A
Application number: US588078A
Authority: US
Inventors: Oliver H Stohldrier
Original assignee: Nat Lead Co
Current assignee: NL Chemicals Inc
Priority date: 1966-10-20
Filing date: 1966-10-20
Publication date: 1969-05-06
Anticipated expiration: 1986-05-06

Description

May 6, 1969 o. H. STOHLDRIER 3,

METHOD AND MEANS FOR SAMPLING PULVERULENT MATERIAL Fil ed Oct. 20, 1966 AIF? ig. 2 IN VENTOR.

OLIVER H. STOHLDRIER AGENT United States Patent Int. Cl. G01n .I/OO US. Cl. 73-422 Claims ABSTRACT OF THE DISCLOSURE A sample of pulverulent material is obtained by passing the pulverulent material between a gas jet and an openended sample collector. Periodically a blast of air is emitted by the gas jet to blow a sample of the material into the sample collector.

The present invention relates in general to sampling devices and more especially to an improved method and means for obtaining samples of pulverulent materials.

For many purposes it is desirable to obtain samples of pulverulent materials flowing in a stream, as for example from one stage of a process to another, which samples are fully representative, as compositions, of the material throughout the stream. Various sampling devices have been used in the past such as for example the auger-type continuous sampler, and a great variety of mechanical devices characterized by a sample receiver adapted to be moved periodically into and out of the stream. Each of these devices has had one serious drawback namely, the ever present possibility of contaminating the sample with abraded metallic particles.

Moreover, earlier devices have been limited by mechanical structure and mode of operation to relatively slow sampling cycles with no means for varying the frequency and duration thereof.

An object therefore of the present invention is to obtain samples periodically from a stream of pulverulent material which are fully representative thereof and which are free of any foreign materials that might result from the operation of the sampling device.

A further object of the invention is to provide a pneumatic sampling which is of simple, low cost construction and involves no moving parts.

Another object of the invention is to provide a pneumatic sampling device wherein samples from a stream of moving pulverulent material may be takenat variable frequencies and duration.

These and other objects, features and advantages of the invention will be described in more detail below with reference to the drawings in which:

FIG. 1 is a vertical elevation, partly in section, of the pneumatic sampling device of this invention.

FIG. 2 is a fragmentary schematic view of modified air supply means for use in conjunction with the timer controlled valve-means of FIG. 1.

In general the sampling device of this invention is pneumatic in principle in that it involves no moving parts but on the contrary employs a short blast of air to remove a sample of pulverulent material from a flowing stream of the same. While it is most probable that the stream of pulverulent material to be sampled will be flowirrg downwardly substantially vertically, the sampling device of this invention is not limited in its operation to vertically flowing streams but may be used with streams flowing at an angle to the vertical or even horizontally if such be the case.

More particularly the sampling device of this invention is one which insures minimum contact with the material 3,442,137 Patented May 6, 1969 to be sampled by employing a short blast of high pressure gas i.e., air to other inert gaseous material, to remove the sample from the stream of pulverulent material being sampled. The short blast of gas is adapted to emanate from one side of the conduit through which the pulverulent material is flowing and to shoot across the stream at substantially right angles to its direction of flow. In so doing the blast of gas picks up a sample of the pulverulent material from the stream and carries it across to the opposite side of the conduit. Here at a point diametrically opposite the gas blast is suitable sample collecting means that collects the sample material segregated from the stream by the gas blast.

The present invention is comprehensive of various means for effecting pneumatic sampling of a stream of pulverulent material and one such means which has been used with considerable commercial success, is described in more detail below.

Referring to the drawings the numeral 10' identifies a conduit, in this instance arranged substantially vertically, through which flows a stream of pulverulent material to be sampled. The pneumatic means for taking a sample from this stream comprises in part, a tubular member 11 adapted to project through an aperture in the wall 12 of the conduit 10 and to be rigidly secured therein by welding or equivalent fastening means indicated by plate 13. The forward end of the tubular member is adapted to project a slight distance into the conduit and is provided with a jet orifice 14, while the opposite or rear end of the tubular member 11 is connected by a coupling 15 to the adjoining end of a pipe line 16 which is an extension of gas supply means 17 to which a gas, i.e. air is fed at superatmospheric pressure from a source not shown. Interposed in the pipe-line 16 between the coupling 15 and the air supply means 17 is a valve-means 18 which in one embodiment of the invention is adapted to be operated automatically by means of a solenoid or equivalent means. It will be understood however that the valve-means 18 may be operated manually if so desired. Where the valve-means 18 is operated by a solenoid the latter, as shown in the drawing, is adapted to be connected in an electrical circuit which includes a timer 19 whereby the frequency with which the solenoid is energized and the length of time between. intervals may be varied thereby varying the frequency with which samples are taken and also the duration of each sampling.

Diametrically opposite the tubular member 11 is sample collecting means 20. The latter is adapted to collect a sample of the pulverulent material shot into it by the air blast and to carry the sample to a point outside the conduit 10 where the sample may be subsequently analyzed. One sample collecting means adapted to perform this function is shown in the drawings as comprising a tubular collector member 20 and a sample receiver 21. The tubular collector 20 is in the shape of a pipe elbow arranged to be rigidly secured in an aperture in the wall 22 of the conduit 10 by welding or equivalent fastening means represented by plate 23.

It is essential to truly representative samples that the sampler collects only the samples shot into it by the air blast and that it be shielded, normally, from pulverulent material flowing through the conduit. To this end the collector 20 is so arranged that its entrance end, indicated by numeral 24, projects into the path of the stream of pulverulent material but is directed downwardly so that in effect it is shielded from the normal flow of pulverulent material through the conduit. The opposite or exit end 25 of the collector member 20 is located on the outside of the conduit 10 and is adapted to discharge samples into the sample receiver 21 for subsequent analysis. In its simplest form the sample receiver may comprise a cupshaped member but it will be appreciated-that the latter may be one of a plurality of such receptacles adapted to be automatically positioned beneath the exit end of the sample collector for receiving successive samples therefrom. Since in commercial applications the sampler will be located almost invariably in an area that is prone to be dusty it is important that the sample receiving receptacle or cup 21 make a dust-tight fit with the exit end 25 of the collector 20 and to this end the latter may be provided with a gasket 26 to seal off the upper end of the cup.

Concerning the frequency and duration of the sampling cycle-in one particular application of the sampler only a very small quantity of sample material was desired and it was found that most commercial timers having the desired cyclic frequency had an on-interval which was much too long to obtain small samples. Hence a modified airsupply means was devised which, as shown in F162, comprised an air chamber 27 provided at its air inlet end with a restricter 28. The opposite end 29 of the air chamber was connected to the air supply line 17. With this arrangement the flow of air to the supply line 17 was restricted with the result that once the timer controlled solenoid has been actuated to open the valve to emit a short blast of air, thereafter the restricter 28 bled air into the air supply line 17 so slowly that even though the solenoid operated valve remained open (because of the long on-interval of the timer) there was not sufficient air pressure to blast a sample from the stream of material being sampled. At the end of the on-interval of the timer the solenoid was actuated to close the valve and air pressure then built up in the supply line 17 suflflciently to blast a sample from the Stream when the valve was again opened.

The pulverulent materials that may be sampled by the device of this invention may include cement, talc, flour and finely divided ore and similar granular materials. However an especially desirable application of the sampler is with continuously flowing streams of TiO materials such as for example, the discharge of Ti0 from a Raymond mill cyclone; or the TiO burdened reaction gases produced in a vapor phase process for producing pyrogenic TiO To illustrate the invention further the particular embodiment thereof above described was used to take samples periodically from a stream of TiO pigmentary material in the discharge duct of a Raymond mill. The jet orifice 14 comprises a A hole drilled in a plug welded in the end of a /s" tubular member 11. The sample collector comprised a three inch 45 elbow diametrically opposite the jet orifice 14. Filtered air was supplied to the solenoid operated valve 18 which in this embodiment was a 2-way valve, normally closed, and provided with a /s" orifice. A Mi" pipe connected the solenoid operated valve 18 to a coupling 15. A variable timer 19 was selected which was set for a five minute period and a duration of /2 second such that the solenoid 18 was operated every five minutes for /2 second to allow air to issue from the jet orifice 14. Approximately 0.005 cubic feet of air passed through the orifice in /2 secondwhich imparted suificient momentum to the TiO pigment particles to carry them across the conduit into the sample collector 20. Samples of TiO pigment from the discharge duct of a Raymond mill were uniformly +325 mesh with no indication of classification or foreign matter.

While one embodiment of the invention has been shown and described it will be apparent that other adaptations and modifications may be made without departing from the scope of this invention.

I claim:

1. A pneumatic device for obtaining a sample of pulverulent material comprising in combination: a conduit through which said pulverulent material is adapted to flow in a continuous stream, a tubular member constructed and arranged in one wall of said conduit, gas supply means arranged to deliver a high velocity gas to said tubular member, sample collecting means constructed and arranged substantially diametrically opposite said tubular member, and valve means constructed and arranged to control the emission of said high velocity gas from said supply means to said tubular member so as to produce a blast of gas from said tubular member, said blast of gas serving to carry a sample of the pulverulentmaterial out of said stream into said sample collecting means.

2. A pneumatic device for obtaining a sample of pulverulent material according to claim 1 wherein said tubular member comprises a jet orifice.

3. A pneumatic device for obtaining a sample of pulverulent material according to claim 1 wherein said sample collecting means comprises a tubular elbow having an entrance end constructed and arranged to extend into said conduit and to be shielded from the stream of material flowing there through.

4. A pneumatic device for obtaining a sample of pulverulent material according to claim 1 wherein said gas supply means comprises a pipe line connected to a pressurized gas source; and said valve means comprises a solenoid operated valve in said pipe line, and a timer for periodically energizing said solenoid.

5. A pneumatic device for obtaining a sample of pulverulent material according to claim 4 wherein said gas supply means comprises a gas chamber arranged to be connected to said valve-means, said gas chamber having a restricter connected to said pressurized gas source.

6. A pneumatic device for obtaining a sample of pulverulent material according to claim 3 wherein said tubular elbow has an exit end arranged to extend outside said conduit; and a sample receiving receptacle associated with the exit end of said tubular elbow.

7. A pneumatic device for obtaining a sample of pulverulent material according to claim 6 wherein a gasket is constructed and arranged to provide a dust tight seal between the exit end of said tubular elbow and said sample receiving receptacle.

8. A method for removing a sample from a continuously flowing stream of pulverulent material comprising: passing said stream of pulverulent material between a gas jet orifice and an oppositely disposed sample collector, and periodically emitting a blast of gas from said jet orifice into said stream substantially in alignment with said oppositely disposed sample collector to carry a sample of said pulverulent material from said stream into said Sam ple collector.

9. A method for removing a sample from a continuously flowing stream according to claim 8 wherein the frequency and duration of said gas blast are variable.

10. A method for removing a sample from a continuously flowing stream of pulverulent material according to claim 8 wherein said pulverulent material is pigmentary TiO References Cited UNITED STATES PATENTS 782,235 2/1905 Gullberg 73-423 1,840,455 10/1927 Lea 73-423 3,016,063 7/1960 Hausmann 302-42 3,250,128 5/1966 Cassel 73-422 LOUIS R. PRINCE, Primary Examiner.

H. C. POST, llLAssistant Examiner.