US1728626A - Pyrometer - Google Patents

Description

Filed June 15, 1927 -nBlYlX- ULM ATTORNEYS.

Patented. sept. 17,1929

T OFFICE RoBEn'rc. PAIRMAN, oF BERKELEY, CALIFORNIA..

PYnoME'rER ,Appucatin med Juneis,

This invention relates to pyrometers and like instruments, and especially to that type which depends upon the differential expansion of two elements for indicating temperatures. y

Pyrometers of the above character usually consist of acasing provided with a dial which is' graduated into degrees, Fahrenheit or centigrade as the case may be, to indicate temperature.

The casing is provided with a tubular eX- 1 tension, preferablyconstructedof a metal having a comparatively high coetlicient of tube'is transmittedthrough a rod having a low coelicientv of expansion to a gauge movement, and this, in turn, actuates a pointer or indicator which swings over the graduated dial and thereby indicates lternperature'. A number of temperature indicating instruments embodying the above-elements and I mechanism have been constructed and used but' from a practical operating point 'of view have, in most instances, proven a failure, due to`the following reasons: Back lash,v and lost motion has been encountered which could not be compensated; the link andfgauge movements employed werediflieu-,lt to adjust; the expanding andfhQn'-expending elements employed would :deteriovrame or disintegrate, when exposed to high temperatures, and their"coeiiicient of exten- L sion would gradually. change, causing ine-or,-V

rect temperature""readings to be indicated. The resultl istliat temperature indicating in'- s'tr'uments of this character have been ractically abandoned in favor -of electrlc or thermo-couple actuated pyrometers.

(The object of the present invention Vis to generally improve and simplify the construction and operation fof pyrometers of the character described (by vproviding eX- panding and non-expanding elements which 5 will stand vhigh temperatures without ldanger of deterioration or change in their coefficient of expansion; [by providing a link and 'connected gauge movement which'may be readily and easily-,adjusted by providing 0 means for positively taking up all back expansion. The expanding movement of the 1927. Serial No. 198,943.

lashgand lost movement; and furtherfby providinga'linkfand'gauge movement which 1s sturdyfand substantial and reliable in op; eration? when subjected to different uses= The pyrometer is shown by way of illustration inthe accompanying drawings, in whichj? C Fig. 1 is -a front view ofthe pyrometer,"l said View being partially in section and par, i i tially broken away to show the operating mechanism. Y 2 is a central, vertical, longitudinal section. Fig. 3 is a cross section, taken on line 3 3 of Fig. 1. y .y

Fig.'4 is an enlarged section pn line 4-4.- 0f. Fia'- 1- y .Referring to the drawings in ldetail and f particularly Figs.- 1 and 2, A indicates a cas ing, consisting of a bottom section 2 anda circular side wall 3; Projecting through the lower portion of the side wall 3,;as` at 4, is a tubular extension 5, on the upper end ofy which is formed a head member 6` and a combinationV bearing` and guide f?.y The tube 5, togeth .,th the'head member is secured'to' the,v lsing in any suitable manner and,J as V'here indicated, by meansl -of screws 8. -Securediin the lower end of the tubular ex- 30 tension 5 is a tube 9. AThe lower end of the tube is closed by means of a pliig or the like indicated at'10, and mounted interiorly ofvrthe tube and guided thereby is a rodll, the'function'of which will be hereinafter described; Slidably mounted in the tubular vextension 5 is a plunger or connectingfrod 12. This plunger rests on the upper end of the rod 11, andthe upper end-of the plunger is pivotally connected, .as at 13, with au. main, actuatinglever, generally indicated vat v14:. This lever is pivotally mounted, as au15, in the bearing 7. The bearing is. slotted lengthwise to form a guidefor the lever 14, andthe center 'portion is 95 drilled to form a .guide for the plunger 12; thevupper end oilthe plunger being slotted, `as vat 16, (see Fig. 2) to straddle and connect with the main actuating lever 14.

Mounted within the casing'A is a gauge 100 movement, which is generally indicated at B. This movement consists of a base plate '17 and a top 'plate 18 which are interspacedwith relation to each other. by means of s acing posts, such as indicated at 19. 'ournaled betweenA the plates is a `spindle I 20, and secured thereon is a small spur gear pinion 21 whieh intermeshes with a segmental rack bar 22. This rack member 'is pivotally mounted, as vat 23,v between the plates'l? and 18 and isprovided with an adjustablelever extension 24 which is connected with the main operating lever. 14 'through means of a4 link 25. l i

The spindle carries an ordinary pointer' or indicator hand 26 and this is movable over a dial 27 which is graduated in degrees =Fahrenheit or' centiUrade-as particular uses may demand. T e gauge movement, generally indicated at B, which has been more or less specifically described, is a standard movement and `no invention Ais claimed as .far as the specific structure involved is concerned, The manner of mounting the movement, however, is new and.

this will be described in detail.

. By referring to Figs. 1, 2 and 3 it will be noted that one end of the base,plate 17 is pivotally secured to the bottom section-2 of the casing by means of a screw or the like, such as indicated at4 28. The opposite end of the base plate is secured to the bottom section 2 by means. of a screw 29. The bottom section 2 is provided withan lelongated f'slot, as indicated at 30, where the screw '29'passes through, and it is thus possible to Vswing' the entire gauge mcvement about the pivotal-connection 28. This is'important as 4it permits adjustment of the indicating handJ 26 with relation to. the graduated dial from a", oint exteriorally of the casing.. f

- lou'nted on the exterior or rear side of the I bottomsection 2 of the casing is a pair of postsf.- such as 'indicated at 31 and 32. The post 31 is adjustable'and the'post 32 is stationary as it is secured to the bottom section 2- of the casing by means of a screw l l33. liA" threaded rod 34 is secured Vat one end, as 'ati 35, to thepost The' opposite fendof the threaded rod extends through 'the post 32 and it carries/a pair of adjusting st :rews 136' and 37.and 'a set or lock screw 38is provided The pivotscrew 29 extends "lock nuts 39on its outer end.

through v`the post 31 and carries a pair of If. itis ldesired toadjustthe pointer"2 y with relation to thelgraduated gauge Ydial stance, if it is`desired to swing the gauge it is only necessary to loosen the set-screw 38 and the lock nuts 39 and one or the other of the adjusting-screws. 36 or v3 7. For in;y

iI movement" about the pivot 28 towards the left, screw 37 is sl'ackened and screw 36 is .v f tightened. vThis willpull the block 3l, the '65 screw 29 and-the gauge movementlongitudinally of the slot 30 towards the leftand as the main operating lever 14 and link 25 are stationary, it will have the same eiect upon the segmental rack 22 as if it were swung about its pivot towardsv the left-hand'side ofthe casing. In other words, the pinion 21, together with the spindle and the indieating hand 26, will swing contraclockwise, and when the desired adjustment is obtained it will only be necessary to tighten the sev- -eral screws, lock nuts, and the adjustment will be maintained.

which depends upon several features, such as the distance between the pivots 13 and 15, the distance between the point 15 and the upper pivotal connection of the link 25, andl uthe position of the adjustable lever 24 with relation tothe-.pivotal point 23. The ratio or the movement, which depends upon vthese distances. can only be adjusted by changing the position of the extension 24 or by changing the position 4of the link 25 with relation to the main actuating lever 14. To permit such adjustment an adjustable plate 40 is employed.

This'adjustable plate 40 is slotted and it is secured-to the upper end of the main operating lever 14 by means of av pair of It is accordingly possible-to if. itl is desired 'to adjasf the indicating A screws, such as indicated at 41. Thev link 25 is pivotally secured to the upper end of the slotted plate, as at '42. By slackening the v screws 41 the plate 40 maybe adjusted upfV wardly or downwardly onfthe lever 14 and the distancebetween the points 15'and '42 may accordingly be adjusted, thereby increasing or decreasing the leverage'or ratio of the movement. x

A similar adjustment isV obtained by moving thev adjustable lever 24 upwardlyv or.

downwardly. with relation to 'the' pivotal point 23. These adjustments are usually madein the factory when the instrument is being tested and oncethe adjustment as been properly made further attentfions' jnotrequired; hence the importance of cnploying an exterior adj ustment` if it is nec- Sary to change the position ofthe indicatmlg 'j l l l l .al The sp1ndle'2 0 1s provided `with anfordinary hair spring 'in the manner of all stand:

hand 26withrelat1on-to the: graduated 'di 1 46; this being secured at one end to the casor playin the bearings or connections otherwise employed, for instance, the pivotal connections between thel link 25 and the connections 13vand 15, 'is taken up by a spring ing and at its opposite endto the adjustable lever 24. This spring exerts a constant pull in the direction ofvarrow a. This pull takes up any slack in the connections of the link 25 and it tends to swing the main operating lever about its pivot 15 in the direction lof arrow b. As this yis the ease the lever exerts a downward pressure on the bearing 15 land the pivotal connection 13 and as such takes up any lost motion or play that mayexist'. It further exerts la downward pressure on the plunger 12 and the rod 11 and maintains these members in constant and intimate contact with relation to each other and also with relation to the plug 10. j

In actual practice the instrument has been 4employed for numerous purposes, such as taking stack temperatures, baking. oven temperatures, lead bath temperatures, exhaust gas temperatures of internal., combustion engines, etc. Tn any of these instances the tubular extension 5 vis exteriorally threaded, as 'indicatedy at 5, and as such serves the function of forming a connection between the instrument and the smokestack, bake oven exhaust manifold, or Awhatever the case may be. Ify the instrument .is inserted in the exhaust'manifold of an internal combustion motor or engine thetube 9, con# taining the rod 11, will extend into the mani#4 fold and the hot exhausting gases will imypinge thereon. The tube 9 is econstructed of -a material having a comparatively high coeilicientv of -expansion while the rod 11- is constructed of a material having an exist-.-

ing low coeiiicient of expansion. Hence when the tube 9 is subjected to gases of high temperature, it tends to expand longitudif nally'and` as the rod 11 d'oes not tend to expand it will settle downwardly in the tube 9, the. plunger 12- will move downwardly.

with the iod 11 and the main operating lever 14 will'- swing about its pivotyl in the direction of arrow b. Link 25.will also move in'the same direction and the segment' 22 willswingv about its pivot 23 towaids the right, thus .transmitting a. rotary movement to' the .spindle 20, the pinion 21 and the indicating hand 26'in a clockwise direction. The

' amount of movement imparted dependsventirely `upon the temperature'to which the tube 9 `is exposed, or, in other words,..to`.

the amount of expansion which takes place in the tube.

If the temperature of the gases decreases the tube will contract or shorten, thus forciing the rod 11? and the plunger '12 upwaraiy.

During contra-cloclwise movement of the indicating hand kthe spring 46 is extended 'and' lduring al clockwise1 movement of the indicating hand the spring is contracted. The spring, however, always remains under tension so that a sufficient pull is exerted at' all 'times to take up all play, back lash and 'lost motion. This is exceedingly important as correct temperature readings could not otherwise be` obtained.

It hasbeen vstated in the preamble to the specification that temperature indicating -instruments constructed along the lines specified `have been constructed and used, but had, practically speaking,l been abandoned for numerous reasons, among them being deterioration, disintegration and change in expanding and non-expanding elements by which the. instruments were' actuated'.

I have discovered that if the tube 9 is'- constructed of Monel metal and the rod 11 ofa fused'slag or quartz a dependable-uniform operation can be secured as, Monel metal will stand high temperatures without oxidizing and without affecting the coeflicient of expansion of the Monel metal; this being also true as far as fused slag or quartz rods are concerned, and it is accordingly im portant that these twospecified elements be employed, to-wit, Monel metal and quartz rods, as they are the only two elements I have so far discovered which are positively dependable. The tubular extension 5 and the plunger 12 may be made of any suitable metal as they .are not subjected to high temperatures. However, it is essential that they be made of the same metal so that they will both simultaneously contract and expand at a uniform ratio., v

It is also more or less important that the same metals be employed within the casing v so lthatsJ uniform expansion of contraction ratlo 1s maintained as all the members are i lunder certain conditionsf'subjected more or less conductedV -or radiant heat. It often happens that instruments of this character are subjected to abuse. For instance, the tube 9 may be subjected to higher 14 and thesegment 22. That is, the segment will swinga'bout the pivot 23 to such an extent that the teeth on the segment will move out of mesh or engagement with teeth on the pinion 21.- The hair spring cooperating with the pinion will in that case un-1 wind and the indicating hand 26 will lose its adjustment. To prevent disengagement of the pinion and the segment 22 a stop lug 60 is' employed. This. lug moves into engagement with the upper post 19 of the gauge movement and thereby limits the movement of the main operating arm 1 4 and the segment 22.l In other words, the mo-v ment the end of the segment reaches the pinion 22 lug 60 engages the post 19, and. further movement or disengagementlof the se ment and pinion is prevented.

Ato,

'main operating lever pivo ing, a link pivotally secured to the adjustaf ble extension on the gear segment, an`ad,

a casing having .a graduated temperature' indicating dial mounted thereon, a base plate mountedv within the casing, a top plate, a' spindle journalled between the plates and having a gear'pinion mounted thereon, a gear segment pivoted between the plates and interineshing with the pinion, an adjustable lever extension' on said gear segment, a

main operating lever pivoted within the casing, a link plvotally secured to the adjusta- ,y ble extension on the gear segment, an adj ustable connection between the opposite end of' the link and the mainoperating lever,

means for imparting movement to the main4 operating lever, and a spring connected atone end with the casing and at the opposite end with the adjustable extension on the gear segment. v n l 2. In a device of the character described, a casing having a graduated temperature indicating dial mounted thereon, a base plate mounted withinithe casing, a top plate, a

spindle-journalled between the. plates and havinga gear pinion mounted. thereon, a

gear segment pivotedbetween the plates and intel-meshing with the pinion, an adjusta ble lever-extension-on said ear segment, a

within the casj ustable connection between theopposite end of the link and themain operatm lever, means for imparting movement to e main operating lever, avspring connected at one end with the casing and at the opposite end with the adjustable extension on the gear segment, and means -for limiting pivotal movement of the gear segment to prevent the gear segment from swinging outl of mesh with the pinion. k'

3. In a device of the character described, a casing having a graduated temperature indicating dial mounted thereon, a base plate mounted within the; casing, a top plate, a spindle journalled between the plates and having a gear pinion mounted thereon, a gear segment pivoted between the plates and inter-meshing with the pinion, an adjustable lever extension von said gear se ment, a vmain operating lever pivoted within the casing, a link pivtally secured to the adjustable extension on the gear segment, an adjustable connection between the opposite endv of the link and the main operating lever, means for imparting movement to the main operating lever, a spring connected at Aone end with the casing and at the'opposite end with the adjustable extension on the gear segment, and a stop lug mounted on the main operating lever to limit the movement 0I the main operating leverV and the gear' segment.`

4. In a device of the. character described, i Y

a casing having a graduated temperature indicating dial mounted thereon, a lbase plate mounted vwithin the casing, a top plate, a spindle journalled between the plates and having a gear pinion mounted thereon, a gear segment pivoted betweenthe plates and intermeshing with the pinion, an adjustable lever extension on said gear segment, a main operating lever pivoted within the. casin av link pivotally secured to the adjustab e extension on thegear segment, an adjustable connection between the opposite end of the link andthe main operating levfer, means for imparting movement to the main operatmg lever, a spring connected at ,one end with the casing and at the'opposite end with the-adjustable extension on the gear segment, a pivotal connection between the base plate and the casing' at a point adjacent the spindle, and an adjustable connection between the opposite end of the base plate and the casing to permit swinging movement of the base plate about the pivotal connection. f Y

, 5:'In 'a device'ofthe character described,

-a casing having a graduated dial mounted thereon, a. gaugemovement within the casing, 'a pointer.v carried bythe gauge movement and lmovable over the dial, a pivotal connection between one end ofthe gau e movement andthe casing, and an. ad'ustaleL connection betweenpthe opposite en of the i gauge movement andthe casingv to permit swinging of the pivotal connection.

gaugeV movement about thesf ing, a pointer carried by the gauge movement and movable over the dial, av pivotal connection between one end 'of the gauge movement and the casing, an adjustable connection between. the yopposite end of the gauge movement and the caslng to permit swinging of' the gauge movement about the pivotal connection, said adjustable connection comprising a bolt extendin through a slot in the casing, a post throng which the bolt passes, a second post, a threaded rod connected with the first named post and extending through the second named post, and adjusting screws mounted on the rod on opposite sides ot' the second named post.

7 In a device of the character described, a tube constructed of expansible material, a casing to which the tube is attached, a seat in one end of the tube having a semi-spherical depression formed therein, a rod of sub stantially non-expanding material engaging the seat and supported thereby, the end of the rod being rounded to engage the depressed seat, a plunger engaging the opposite, end of the rod, a rounded depressed seat in the plunger, and a rounded end on the rod to enter the seat. 4

c ROBERT C. PALRMAN.

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