US1474403A - Method of making thermometer bulbs - Google Patents

Description

F MAKING THERMOMETER BULBS Filed Nov. l2, 1920 M lo 0 s, ,1o. M

0 o m s Patented Nov.' 20, 1923.A

TUNITEDl sTATl-:s

A A1,474,403. PATENT oFFlcE.

LEE F. CHANEY, -OF SPRINGFIELD, OHIO, ASSIGNOB TO THE CHANEY MANUFACTUR- ING COMPANY, OF SPRINGFIELD, OHIO, A CORPORATION OF OHIO.

METHOD OE MAKING THERMOMETER BULBS.

Application le'd November 12, 1920. Serial No. 428,658.

To all whom. it' may concern:

Be it known that I, Lne F. CHANEY, a lcitizen of the United States, residing at Springfield, in the county of Clark and State of Ohio, have invented certain new and useful Improvements in Methods of -Making Thermometer Bulbs, of which the following is a specification.

This invention relates to thermometers of the type known as insulated thermometers, and generally designated as dairy or floating thermometers, and more particularly to a method of manufacturing the same, whereby the process of production of such devices will not only be simplified, but will be cheapened without impairing their efficiency and which will enable uniformity of production and afford an instrument having a reenforced bulb, of maximum strength.

A further object of the invention is to afford a process whereby such instrument may be rapidly and accurately produced by' unskilled labor with minimum losses, from distortion and breakage of the parts.

With the above primary and other incidental objects in view as will more fully appear in the specification, the invention consists of the features of construction, the steps and operations and the sequence and combinations thereof, or their equivalents, as hereinafter described and set forth in the claims.

Referring to the drawings, Fig, 1 is a side elevation of the completed thermometer. Fig. 2 is a detail sectional view showing the preparation of the insulating or casing tube. Fig. 3 is a detail View illustrating the preparation of the capillary tube, having a punctured bulb. Fig. 4 illustrates the assembly of the capillary tube and casing tube prior to fusing. Fig. 5 is a detail sectional view of the united capillary and casing tubes after completion of the fusing operation. Fig. 6 illustrates a modification of the construction shown in the preceding figures. Fig. 7 illustrates the reinforcement of an ordinary thermometer bulb by the herein described process. v p Like parts are indicated by similar characters of reference throughout the several views.

A thermometer of lthe insulated o r float-- ing dairy type as shown in Fig. 1 comprises an outer or casing tube 1, enclosing the capillary tube 2, which is integrally united with the outer or casing tube thru a common bulb 3. The lower portion of the casing tube 1 surrounding the capillary tube 2 is usually weighted by means of shots, lead or other ballast material, 4, which is retained in place by a deposit of wax 5v or some adhesive. Inserted within the casing tube 1,

and adjusted to proper relation with" the column of indicating fluid, whether mercury, or alcohol, orvother fluid, within the capillary tube 2, is a graduated paper scale 6, upon which is indicated by the height of the column of indicating liquid within the capilla tube the corresponding temperatures.

eretofore various methods of manufacturing these insulated or floating dairy thermometers have been in use. The predominating step in the manufacture of such devices has been that of forming the bulb Y 3 upon the exterior or casing tube and uniting the capilla tube 2 therewith. Various rocesses haverbeen employed to this end. e of the popular methods has `been to expand or flare the lower end of the capillary tube, and to unite the edge ofsuch flared or expanded portion with the wall of the casing tube adjacent to the lower end ,thereof and subsequently blow or otherwise form the bulb 3 from the wall of the casing tube, below the zone of cohesion of the capillary tube thereto.

A variation of this method also commonly employed has been to first produce by blowing or otherwise a bulb upon the extremity of the capillary tube, which is then inserted within the casing 0r insulating tube 1. The bulb upon the capillary tube 1n this process in only temporary. The adjusted tubes are then heated to fuse them one to the other, and the bulb upon the capillary tube is bursted or ruptured by blowing thru the small end of the capillary tube, While the bulb is in a heated or plastic condition. It will be understood that the capillary tube projects beyond the extremity of the casing tube at this stage of the manufacture. After the bursting or dissipation of the bulb upon the capilla tube, b such blowing operation, the p'rrmanentybulb is then formed from the material of the outer or casing tube 1. This skill as does tlat of fiaring the end of the capillary tube preparatory to uniting it with the casing tube. Moreover, both processes rocess requires considerable;

\ casing tube are caused to unite.

adord a bulb having comparatively thin walls, inasmuch as the bulb is formed by stretching the material of the casing or outer tube, and hence reducing its thickness. The bulb walls thus consist of a single reduced thickness of material. Another diiiculty ot these processes has been the difficulty of securing uniformity of capacity in the manipulation olf the wall of the larger tube in forming such bulb The present process is designed to overcome these dimculties, and to a'ord a method by which these thermometers may be economically and rapidly produced byl f persons unskilled in glass blowing. To this end, the outer or casing tube l is prepared by drawin one end to a suitable taper, as shown in ig. 2 leaving the end ot such tapered portion open as at Z. The capillary tube 2 is prepared by blowing or otherwise .forming at one end thereof, a closed bulb 8 as is commonly employed in the ordinary type of' thermometers. While the bulb 8 of the capillary tube 2, is still in -a plastic condition or upon reheating the bulb subsequent to its formation, the bulbdis punctured as shown at 9. This puncture is a comparan tively smallvent, and may be eected without destroying the symmetry of the bulb by various methods. @ne of these methods, and perhaps the most convenient is to provide in the table or bench of the worker, an upstanding wire pin or stud, upon which the finished bulb may be thrust while still in a plastic condition, thereby causing such pin or stud to puncture the bulb to al'ord the vent 9. Another convenient method of forming such vent or opening 9, is to touch the bulb to a hot metal plate or other heated support havin thereon a suitable glass bait, and then pul ing the bulb away, thereby pullin a portion of the material from the "wall o the bulb, leaving the hole or Vent 9 i A. third method which has been therein. used with success is to fuse the hole or vent 9 in the bulb by means of a pin flame direct- The capillary tube with the ed thereon. punctured bulb 8 is then inserted within the outer or casing tube 1 until the bulb fits closely within the tapered. extremity of such casin tube, and the adiusted tubes are subjecte to fusing heat. In this fusing operation, the wall of the bulb and the wall of the The wall of the casing tube being more directly subjected to the heat, becomes plastic first, and to a greater degree. Under the action of the fusing heat the wall of the casing tube is deflected inwardly into conformity with the bulb 8 of the capillary tube, which in reality forms a core or form about which the .i wall of the outer or casing tube is shaped.

ln this fusing operation, the terminal opening 7 of the casing tube is closed or sealed in many instances before the casing tube has nea/inca neath the bulb 8 and within the closed end oit the casing tube as at 13 Fig. ll. llt is to provide for the escape oit such entrapped air or gases, that the vent 9 is provided in vthe bulb 8. By the present process, any a1r which may be so entrapped escapes thru the vent 9 and thence outward thru the capillarytube 2, as the walls of thecasing tube gradually close over the bulb 8. The Wall of the casing tube being'in a fused cond1tion also contracts somewhat above the bulb as shown in Fig. 5. ln this gure the original position of the tapered end of the casing tube is shown by dotted lines while the ultimate shape ot'- lthe casing tube is shown by solid lines. The tube is finished by drawing out the end of the casing tube, leaving the usual teat 10 which eectually closes the orice 'or vent 9 in the bulb. By this construction it will be seen that the resulting bulb has walls et double thickness. That is to say, the finished bulb comprises the initial bulb formed upon the capillary tube 2 around which is formed and integrally united therewith, an enclosing bulb formed from the material of the outer or casing tube. This aords a bulb of maximum strength, and moreover the size of such bulb gaged by that of the inserted bulb- 8, which 'forms the core or lining.

Tn Fig. 6 there is shown a modification in which the perforation 9 is omitted from the initial bulb 8. lln this construction the capillary tube 2 with the bulb 8 intact, is inserted within the tapered portion of the casing tube l, which tapered portion is of such size or cut 0H to such proportion that ythe bulb 8 approaches quite closely to the ex- A/tremity ofrthe tapered end of the casing The relation of the bulb to the end,

tube. of the casing tube is such that the material of fthe tapered casing walls projecting beyond the bulb 8 is insuflicient tocompletely cover the bulb when fused. The relation of the tapered walls of the casing tube is shown in dottedlines prior to fusing and in solid lines after completion of the fusing operation. By this relation and proportion of parts, the fusing of the casing tube does not completely close oil", any cavity or recess nor trap any body of air. To the vcontrary there is afforded in the partially completed product a cent-ral orifice l1 thru which any body of air or-heate-d gas may escape. ln other Vwords the walls of the casing tube donot Mtl lll

the glass rod and partially completed tube to ladhere and then pulling out the fused portion of glass to form the teat 12.

In the event that it is found that the bulb is notl of sufficient size, it may be increased by heating and blowing thru the capillary tube 2 in the usual manner, without however, rupturing orbreaking the bulb as has heretofore been the practice. Thus after the inner core bulb or lining and the outer cas- 'ing have been united, to form a double from the bulb 8 into the passageway of the lcapillary tube. 2 is maintained perfectly smooth, even and` uniform, the bore of the capillary tube and the recess of the bulb 8 merging uniformly and gradually one into the other, which facilitates the subsequent steps of exhausting4 the air and moisture or gases from the bulb and tube.v After the bulb has been completed, as herebefore described, the capillary tube and bulb are filled with indicating liquid, by any of the usual orwell known processes, -as for instance, by the process described in my prior Patent No. 1,345,347, issued July 6,1920, and the tube is calibrated and the scale adjusted thereto in uniformity with said calibration, by any suitable calibrating process, as foro instance as described in my prior` Patent No. 1,391,878, issued September 27, 1921.

rfhe exhaustion of air and gas and subsequent lling of the tube and calibrating thereof having been completed, the capillary tube is finished by closing the upper or outer end thereof, by fusing the same, and the end of the casing tube is also closed by fusing in the usual manner.

i The method heretofore described may be utilized for reinforcing the bulb of an ordinary thermometer tube as shown in Fig. 7, wherein a short glass tube 14: is fused into conformity with the bulb 8 as indicated at 15 to afford walls of increased thickness, to compensate vfor the stretching of the walls of the ordinary bulb due to the expansion of the material in its formation.

By the herein described process, thermom eters of the type heretofore described, are produced rapidly and economically by persons unskilled in the glass blowing art, and with minimum losses from breakage or dis-l tortion. While the preferred mode of procedure has been shown and described, it will be understood that the invention is not limited to the exact details, nor specific steps, and changes therein and modifications thereof, may be made withinl the legitimate and valid scope of the appended claims without departing from the spirit of the invention or sacrificing its advantages.

Having thus described my invention, l claim:

1. The herein described process of producing a thermometer tube, comprising pro..- viding a casing tube, and a capillary tube, forming a bulb upon one end of the capillary tube inserting the bulb of the capillary tube within the casing tube, heating the portion of the casing tube enclosing the bulb and utilizing the bulb as a form or core to which the casing tube is made to conform and adhere to a'oifd a reinforced bulb common to both tubes.

2. rllhe herein described process of producing thermometers comprising providing a casing tube and a capillary tube, forming a bulb upon the extremity of the capillary tube, inserting the capillary tube and bulb within the casing tube and contracting the casing tube about the capillary tube bulb with which it is integrally united.

3. rfhe herein described process of producing a thermometer tube comprising providing a casin tube, inserting the capillary tube 'bulb withm the casing tube and utilizing the bulb as a core or form about which the casing tube is shaped, and to which it is integrally united.

4. rilhe herein described process of producing a thermometer tube, comprising providing a casing tube and a capillary tube, forming a bulb within the casing tube and utilizing the bulb as a core or form about which the casing tube is shaped, and providing a vent for the escape of air and gases from intermediate the bulb and casing tube during the shaping process.

5. The herein described process of producing thermometer tubes comprising providing a bulb upon one end of a capillary tube and a casing tube one end of which is tapered, puncturing the bulb, inserting the punctured bulb within the tapered portion of the casing tube, heating the portion `of the casing tube enclosing the bulb and causing it to conform to and unite with the bulb and seal the puncture therein.

6. The herein described method of forming thermometer tubes consisting in providing a bulb at one end of a capillary tube inserting such bulb within a casing tube, an subsequently forming a bulbupon the casing ube around and enclosing the capillary tube ulb.

7. TheA herein described method of reinforcin thermometer tube bulbs, consisting in ut' izing the bulb as a core or form and ne I l u i inmune shaping an exterior shell about such bulb in utilizing the bulb 'as a lcore or form and .with which the shell is integrally united by shaping about such bulb an exterior adherfusing. ent shell, and providing a vent for lthe l5 8. The herein described method of reinescape of air and gases from between the 5 forcing thermometer tube bulbs, consisting shell and bulb during the formingoperation.l in puncturing the bulb, and forming a shell ln testimony whereof, .l have hereunto about the exterior of the bulb and over the set my hand this 5th day of November A. l). puncture thru which heated air and gases 1920. r

may escape from such shell during the v V LElElF. CHANEY. 10 forming' operation. Witnesses. V

9. 'The herein described method of rein- W. F. HEROLD.

forcing thermometer tube bulbs, consisting, JOHN B. MGGREW.

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