US3177360A

US3177360A - Diffractometer with a rotatable support to hold plural samples for automatic analysis of crystalline material

Info

Publication number: US3177360A
Application number: US223717A
Authority: US
Inventors: Jr Gustaf F Hague; Milias Emmanuel
Original assignee: Norton Co
Current assignee: Saint Gobain Abrasives Inc
Priority date: 1962-09-14
Filing date: 1962-09-14
Publication date: 1965-04-06
Anticipated expiration: 1982-04-06

Description

Aprll 1965 G. F. HAGUE, JR ETAL 3,177,360

DIFFRACTOMETER WITH A ROTATABLE SUPPORT TO HOLD PLURAL SAMPLES FOR AUTOMATIC ANALYSIS OF CRYSTALLINE MATERIAL 2 Sheets-Sheet 1 Filed Sept. 14, 1962 44 I Z4 :6 4 I I00 3Z\\ s 1 2o ATTOENEY p 1965 e. F. HAGUE, JR ETAL 3,177,360

DIFFRACTOMETER WITH A ROTATABLE SUPPORT TO HOLD PLURAL SAMPLES FOR AUTOMATIC ANALYSIS OF CRYSTALLINE MATERIAL Filed Sept. 14, 1962 2 Sheets-Sheet 2 4 Fig.3 I8

AIR SUPPLY NVENTO s. 605774;- E'H/ euE IE- EMMANUEL lL/AS A TTQBNE) United States Patent 3,177,360 DIFFRACTOMETER WITH A ROTATABLE SUP- PORT TO HOLD PLURAL SAMPLES FOR AUTO- MATIC ANALYSIS OF CRYSTALLINE MATERIAL Gustaf F. Hague, Jr., Princeton, and Emmanuel Milias, Worcester, Mass, assignors to Norton Company, Worcester, Mass., a corporation of Massachusetts Filed Sept. 14, 1962, Ser. No. 223,717 7 Claims. (Cl. 250-515) This invention relates to X-ray diifractometers for analysis and identification of crystalline material and has for its principal object to provide for substantially automatic operation thereof with a minimum of attendance.

As herein illustrated, the apparatus comprises means for delivering .a beam of radiant energy; means for sup porting a plurality of samples of crystalline material to be analyzed in spaced relation for movement of one sample at a time to a position such as to expose that sample in the direct path of said beam; detecting means sensitively responsive to the impact of radiant energy of the beam which is reflected from and diffracted by the sample; oscillatable means operative to vary the angle of incidence of the beam, relative to the sample; and means operative, at each extremity of oscillation of said oscillatable means, to effect movement of the support to move successive samples into and out of the path of the beam of energy. The means for delivering a beam of radiant energy herein is an X-ray tube, the detecting means is a Geiger counter, and the support for the samples isa table supported with its surface parallel to the axis of oscillation on which are clamps for holding samples on the table with portions extending radially therefrom, with their upper surfaces coinciding with the axis of oscillation. A ratchet and pawl provide for rotating the table to move successive samples into position for analysis in the path of the beam.

The pawl is actuated to rotate the ratchet by an air-operated motor to which air is supplied to move the pawl and from which air is allowed to bleed following admission thereof to the motor to permit the pawl to be retracted. Admission of air to the motor is effected at each end of the oscillation by adjustable switch-actuators supported for movement with oscillating portions of the mechanism to operate a switch at each extremity of the oscillation which, in turn, energizes the solenoid of a solenoid control valve to permit air to flow from a source of air to the cylinder. A positioning element on the pawl, by engagement with a face of a tooth on the ratchet, provides for stopping rotation of the table at a precisely predetermined position relative to the beam, and a spring-pressed friction element engaged with the table serves to hold the latter in position following retraction of the pawl. Oscillation of the table and rotation thereof may be increased or decreased by adjustment of the adjustable switch-actuators.

The invention will now be described in greater detail with reference to the accompanying drawings wherein:

FIG. 1 is an elevation of an X-ray ditfractometer showing an indexable table associated therewith for supporting a plurality of samples for analysis;

FIG. 2 is a plan View of the indexable table, broken away in part to show the indexing means, the means for effecting indexing, and the means for mounting the table on the dilfractometer; V

FIG. 3 is an elevation of the indexable table showing the relation of a sample to be analyzed to the axis of oscillation;

FIG. 4 is a section taken on the line 44 of FIG. 1, showing the adjustable switch-actuators for reversing oscillation of the table; and

FIG. 5 is a diagrammatic view of the relation of the X-ray tube, sample slide to be analyzed, and a Geiger counter.

"ice

Crystalline materials have definite arrangements of atoms which produce, by diffraction of radiant energy, a pattern characteristic of the material, thus providing means for analysis and identification of the material. An X-ray diifractometer may be used for this analysis of the kind in which the crystalline sample is oscillated relative to an incident beam of radiant energy and in order to automate such analysis so that constant attendance is not necessary, this invention concerns providing an indexable table for supporting a plurality of crystal samples, automatically operative at the end of each oscillation of a sample, relative to the beam of radiant energy, to move the next sample in succession into position for analysis.

As herein illustrated, the X-ray diffractometer is of conventional manufacture and comprises a base 10 and upstanding frame 12, the latter supporting in spaced bearings 14 and 16 a pair of concentrically arranged inner and

outer shafts

18 and 20 for rotation about a horizontal axis, with an end 22 of the shaft 18 extending axially beyond the bearing and outer shaft at one side of the frame.

A device 24 for delivering a beam of radiant energy is mounted on the frame above and at one side of the projecting end 22 of the shaft 18 by a bracket 26 so that the beam emitted from the device intersects the axis of rotation of the

shafts

18 and 20. As herein illustrated, the device 24 comprises an enclosed X-ray tube 28 and a slotted plate 30 for limiting the beam projected thereby to substantially parallel rays.

A rotatably mounted support 32 for carrying a plurality of crystalline material samples s, for example in the form of slides to be analyzed, is mounted by means of a horizontally disposed bracket arm 34 and an adjustable clamping collar 36 on the projecting end 22 of the shaft 18. A shaft 37 has a bearing portion, upon which the support 32 is mounted for rotation in a plane parallel to the axis of the shafts, the support being rotated stepwise about shaft 37 to move one crystal at a time to a position in the path of the beam with its reflecting surface coinciding with the axis of rotation of the shafts. The shaft 37 is fixed to the bracket arm 34. A plurality of spring clamps 29, fastened to the support 32 at uniformly spaced positions peripherally thereof, provide for holding the sample slides on the table with portions thereof projecting radially outward from the peripheral edge. The means for effecting rotation of the table will appear hereinafter.

A detecting device 40 is supported by a bracket 42 secured eccentrically to a large worm wheel 44, the latter being fixed to the outer shaft 20, the bracket holding device 40 above the projecting end 22 of the shaft 18 opposite the means 24 for delivering the beam of radiant energy onto the sample, the device 40 being sensitively responsive to the impact of the radiant energy of the beam which is reflected from and diffracted by the crystalline sample. The detecting device 40, employed herein, comprises a Geiger counter 46 and a receiver 48 containing a narrow slot for excluding all but the parallel rays of reflection;

In order to move the X-ray relative to the sample to produce the diffractive pattern characteristic of the material, the sample is rotated about the axis of the

shafts

18 and 20 through a predetermined angle relative to the beam emitting from the X-ray tube to change the angle of incidence of the beam. In order to measure and record the diffraction throughout oscillation of the sample, the detecting device 40 is also oscillated about the axis of the

shafts

18 and 20. Oscillation is effected by the worm gear 44 which is driven first in one direction and then the other by a reversible motor M through in one direction or the other.

shafts

18 and 20 and gears 58, and 6t) fixed to ajackshaft e62 which'mesh respectively, with the gears '56 and 54.

In order to maintain the angle of reflection constant throughout oscillation the gear train is designed topro:

vide a 1:2 ratio of rotation of the

shafts

18 and 20.

' Reversal of the direction of rotation of the worm 44 is effected by reversing the motor M This is accomplished by suitable means such as a reversible switch S for reversing the direction of flow of current through the motor and adjustable actuators operative, by one'or the other ofthe shafts, for alternately actuating the switch S when the shafts have rotated a predetermined distance By adjustment of the actuators the angle of oscillation of, the shafts may be increased or decreased thereby to increase, or decrease the angle of observation.

In accordance with this invention, each time the support for the samples and the detector reach an extremity of oscillationas limited by the switch-actuators and the direction of oscillation reversed, the support is moved to advance a succeeding one of .the samples on the support into a position in the path of the beam of radiant energy for analysis. As herein illustrated, the support is in the form of a circular table 70 adapted to be rotated on the shaft 37 by a ratchet and

pawl

72 and 74. The

ratchet'72 is provided with teeth 76 corresponding in number to the number of samples mounted on the table.

The pawl and is fixed to the underside of the table; 74 is pivotally supported at one end of an arm 78, the other end of which is pivotally mounted on the arm 34. A light spring 30, stretched between the pawl 74Qand the arm 78, pulls the pawl inwardly against'the ratchet.

4 thecylinder 86. By adjustment of the collars 1% and hence of the arms 98'on the shaft 20, the angle at which the air valve V is opened may be adjusted so as to correspond in time with the reverse of oscillation of the table. A switch L provides for supplying current a source to the switches S S and S In'the preferred form of the invention, there is also provided means to delay the starting of the motor M at each reversal or actuation of the switch S 'for the purpose of separating the analysis of each slide recorded from by a graph type recorder used with the apparatus. The

recording apparatus runs continuously and by interrupting the motor circuit for a predetermined interval between samples,'an identical symbol, will appear on the graph between each analysis, indicating to the operator, where each anaylsis begins and'ends, which is most helpful. The means to delay the starting of the-motor M after each reversalof the switch S comprises a pair of time delay relays TD and TD each wired in series with one of a pairof contacts of the reversing switch S operated by the rotation of the arm 107 when the shaftltlfi is rotated in either direction; The time delay relays are alternately energized and are of the adjustable type that begin a timing, period on energization, at the end of which the contacts close. When the contacts of the time delay relay TD clo'se, current passes therethroughenergizing the relay CR immediately closing the, contacts and starting the motor M rotating in one'directio'n. When the contacts of the time delay relay TD close, the relay CR is energized closingiits contacts causing the motor M to rotate in an opposite direction.

Itis obvious that the index table may be changed in size to provide fora lesser; or greater number of clamps The arm 78 is, in turn, held by a heavier spring 82 against a rod 84 protruding from a cylinder 86, by means of which the rod may be advanced to in turn advance the pawl '74 against the base of a tooth 76. To insure accuracy of the index position, that is, to terminate rotation of the table at an accurately predetermined position, the arm 78 is provided with apositioning lug 88 which, by engage ment with the face of 'atooth 76, stops the-table at said predeterminedposition. Air pressure is supplied to the cylinder 86 to advance the pawl whereupon the pressure is cut off and the air is allowed to leak from the cylinder through a suitable bleede'r passage 89. As the air bleeds from the cylinder 86a spring 9tl-retracts the rod 84.

Retraction of the rod 84 allows the pawl to be retracted,

by the spring-82 to a position in which the spring 82 1 becomes'effective to pull the pawl 74 into engagement with the succeeding tooth of the ratchet. Retraction of the pawl 74, however, disengages the positioning lug 88 from the face ofthe tooth and to insure preserving the position of the table, following such retraction, a coiled spring 92 (FIG. 3) is mounted on the shaft 37 "between av collar '94 fastened thereto and a friction disc 96 on the shaft to hold the latter frictionally engaged with the top of the table. V

Indexing of the table at each end of oscillation is efalternately moves one or the other of the arms 98 into a for the purpose ofil-lustration only andthat this invenengagement with a lever arm 164 fastened to a shaft ltlfi. f

The shaft 106 has'fixed to it a switch actuator 108 supply current through a conductor C to the solenoid R of'a solenoid-operated air v-alveV opening it each time the solenoid is energized to allow air to How from an air supply, through a gate valve VG, air filter AF, pressure-reducer PR, the valve V and a flexible pipe P to,-

for attaching samples for analysis; that the indexing of the table 70 may be effected by an electrically operated motor in lieu of the air-operated cylinder 86'; and thatthe means for producing the beam of "radiant energy and the detector for receiving its reflectionmay be of any known kind suitable for: the purpose instead of thelX-ray tube and Geiger counter employed herein." The difiracto'meter, provided with theindexing table as'herein' illustrated, is manufactured by the North American Phillips Company, Inc, and is available as a Norelco'X-ray Diifractometer Type No. 42202. 7 V V 7 In the use of the device, the index table may be loaded to its capacity with samples and operation of theapparatus initiated by closing the main switch I Analysis of the samples, one after another, will then take place y oscillation of the index table and detector through successive cycles'until'the entire number of samples have been analyzed whereupon the apparatus is stopped, for example, by means of a counter T designed to open the switch L In practice, however, the apparatus is operated continuously byremoving samples from the index table after a cause of the number of samples that can be mounted on' the table at one time, the machine does not require constant attention of theoperator after subjecting each sam-' pie to analysis. I I I I It should be understood that the present disclosure is tion includes all modifications and equivalents which fall within the scope. of the appended claims. f

We claim: a 1. Apparatus for use in the analysis of crystalline material, saidapparatus comprising means for delivering an X-raybeam of radiant energy, means for supporting a plurality of samples of crystalline material to be analyzed inspaced relation for movement of one sampleat a time to a positionsuch as to'expos e that sample the'direct path of'said beam, means operative tooscillate the support through a predetermined angle to change the angle of incidencev of said'beam, detecting-meanssensitively responsive to the impact of the radiant energy of said beam which is diffracted by the sample throughout oscillation of the support, reversible driving means operative to effect oscillation of the support, means operative to effect reversal of the driving means, said last-named means being adjustable to change the angle of oscillation, and other means operative, concomitantly with the operation of the reversing means, to effect a pre-deter-mined amount of rotation movement of the means for supporting the samples.

2. Apparatus for use in the analysis of crystalline material, said apparatus comprising means for delivering an X-ray beam of radiant energy, means for supporting a plurality of samples of crystalline material to be analyzed in spaced relation for movement of one sample at a time to a position such as to expose that sample in the direct path of said beam, means operative to oscillate the support through a predetermined angle to change the angle of incidence of said beam, detecting means sensitively responsive to the impact of the radiant energy of said beam which is diffracted by the sample throughout oscillation of the support, a reversible motor for effecting oscillation of the support, means operative to reverse the motor, a pawl and ratchet operative to rotate the support, and means operative, concomitantly with the reversal of oscillation of the support, to effect operation of the pawl and ratchet to turn the support 'a distance corresponding to the distance between successive samples.

3. Apparatus for use in the analysis of crystalline material, said apparatus comprising means for delivering an X-ray beam of radiant energy, means including a table for supporting a plurality of samples of crystalline material to be analyzed in spaced relation for movement of one sample at a time to a position such as to expose that sample in the direct path of said beam, means operative to oscillate the support through a predetermined angle to change the angle of incidence of said beam, detecting means sensitively responsive to the impact of the radiant energy of said beam which is diffracted by the sample throughout oscillation of the support, a first reversible motor for effecting oscillation of the support, switch means for reversing the current to the motor, a switch actuator operative, by oscillation of the support through a predetermined angular distance, to actuate the switch means, a pawl and ratchet operative to effect rotation of the table, a second motor operative to advance the pawl against a tooth of the ratchet to rotate the table a distance corresponding to the distance between samples, means operative, concomitantly with the reversal of said switch means, to effect operation of said second motor, and means operative, during the interval between successive oscillations, to retract the pawl for engagement with the succeeding tooth of the ratchet.

4. Apparatus for use in the analysis of crystalline material, said apparatus comprising means for delivering an X-ray beam of radiant energy, means for supporting a plurality of samples of crystalline material to be analyzed in spaced relation for movement of one sample at a time to a position such as to expose that sample in the direct path or" said beam, means operative to oscillate the support through a predetermined angle to change the angle of incidence of said beam, detecting means sensitively responsive to the impact of the radiant energy of said beam which is diffracted by the sample throughout oscillation of the support, a first reversible motor for efie'cting oscillation of the support, switch means for reversing the current to the reversible motor, adjustable actuators operative, by oscillation of the support through a predetermined angle alternately, to reverse said switch means, apawl and toothed ratchet operative to rotate the support, a second motor operative to advance the pawl against a'tooth of the ratchet, to rotate the support a distance corresponding to the distance between samples,

means operative concomitantly with the reversal of the reversible motor to effect operation of said second motor, a positioning element on the pawl operative, by contact with a face of the tooth advanced thereby, to terminate rotation of the support at a precisely predetermined position, means operative to retract the pawl into engagement with the succeeding ratchet tooth following operation of the motor, and means yieldably engaged with the support operative, by frictional contact therewith, to hold the support at said predetermined position following retraction of the pawl.

5. Apparatus for use in the analysis of crystalline material, said apparatus comprising means for delivering an X-ray beam of radiant energy, means for supporting a plurality of samples of crystalline material to be analyzed in spaced relation for movement of one sample at a time to a position such as to expose that sample in. the direct path of said beam, means operative to oscillate the support through a predetermined angle to change the angle of incidence of said beam, detecting means sensitivity responsive to the impact of the radiant energy of said beam which is diffracted by the sample throughout oscillation of the support, a reversible motor for effecting operation of the support, a stepping device operative to rotate the support comprising a ratchet fixed to the support, a pawl held yieldingly engaged with a tooth of the ratchet, an air-operable motor, means operative to supply air pressure to the motor at each end of the oscillation of the support to advance the pawl against the tooth with which it has contact to turn the support a distance corresponding to the distance between teeth, a vent operative to bleed the air from the motor during the interval of oscillation, and means operative, concomitantly with venting of the air from the motor, to retract the pawl into engagement with the succeeding tooth on the ratchet.

6. Apparatus for use in the analysis of crystalline material, said apparatus comprising means for delivering an X-ray beam of radiant energy, means for supporting a plurality of samples of crystalline material to be analyzed in spaced relation for movement of one sample at a time to a position such as to expose that sample in the direct path of said beam, means operative to oscillate the support through a predetermined angle to change the angle of incidence of said beam, detecting means sensitively responsive to the impact of the radiant energy of said beam which is diffracted by the sample throughout oscillation of said support, a reversible motor for effecting oscillation of the support, a stepping device operative to' rotate the support comprising a ratchet fixed to the underside of the support, a pawl held yieldingly engaged with a tooth of the ratchet, an air-operable motor, a solenoid-operable valve operative to supply pressure to the motor to advance the pawl against the tooth with which it is engaged, means operative, at each extremity of the oscillation of the support, to pulse the solenoid, a vent operative to bleed pressure from the motor during the interval between reversal of oscillation, and a spring operative, concomitantly with the bleeding of the cylinder, to retract the pawl into engagement with the next tooth of the ratchet.

7. Apparatus for use'in the analysis of crystalline material comprising means for delivering an X-ray beam of radiant energy, means [for supporting a plurality of samples of crystalline material to be analyzed in spaced relation for movement of one sample at a time to a position such as to expose that sample in the direct path of said beam, means operative to oscillate the support through a predetermined angle to change the angle of incidence of said beam, detecting means sensitively responsive to the impact of the energy of said beam which is difiracted by the sample throughout oscillation of the support, recording means cooperating with said detecting means to make a permanent record of the reflected energy impacted on said detecting means, a first reversible motor for effecting oscillation of the support, control means for effecting reversal of the motor and direction operative at'either end of an'oscillation to operate said control means to reverse the motor for reversing the direction of the oscillation, a pawl and toothed ratchet operative to move the support in a stepwise rotation, a second motor to advance the pawl against a tooth of the ratchet to rotate the support one'step corresponding to the distance between samples, means operative concomitantly with the reversal of the, reversible motor to effect operation of the second motor, means: operative to retract the pawl into engagement with the succeeding ratchet tooth following operation of the motor, and time delay means to preclude operation of said reversible motor at the start of each reversal of oscillation to produce a record indicating the beginning andending of each oscillatiom References Cited by the Examiner UNITED STATES PATENTS RALPHG. NILSON, Primary Examiner.

Claims

1. APPARATUS FOR USE IN THE AALYSIS OF CRYSTALLINE MATERIAL, SAID APPARATUS COMPRISING MEANS FOR DELIVERING AN X-RAY BEAM OF RADIANT ENERGY, MEANS FOR SUPPORTING A PLURALITY OF SAMPLES OF CRYSTALLINE MATERIAL TO BE ANALYZED IN SPACED RELATION FOR MOVEMENT OF ONE SAMPLE AT A TIME TO A POSITION SUCH AS TO EXPOSE THAT SAMPLE IN THE DIRECT PATH OF SAID BEAM, MEANS OPERATIVE TO OSCILLATE THE SUPPORT THROUGH A PREDETERMINED ANGLE TO CHANGE THE ANGLE OF INCIDENCE OF SAID BEAM, DETECTING MEANS SENSITIVELY RESPONSIVE TO THE IMPACT OF THE RADIANT ENERGY OF SAID BEAM WHICH IS DIFFRACTED BY THE SAMPLE THROUGHOUT OSCILLATION OF THE SUPPORT, REVERSIBLE DRIVING MEANS OPERATIVE TO EFFECT OSCILLATION OF THE SUPPORT, MEANS OPERATIVE TO EFFECT REVERSAL OF THE DRIVING MEANS, SAID LAST-NAMED MEANS BEING ADJUSTABLE TO CHANGE THE ANGLE OF OSCILLATION, AND OTHER MEANS OPERATIVE, CONCOMITANTLY WITH THE OPERATION OF THE REVERSING MEANS, TO EFFECT A PRE-DETERMINED AMOUNT OF ROTATION MOVEMENT OF THE MEANS FOR SUPPORTING THE SAMPLES.