The indexing time between the various stations can be quite small, e.g. They can not be applied in regions where highly accurate results are desirable. Preferably, an inert gas such as nitrogen is used. Hold the thermometer in a vertical position, bulb end down, 4 to 6 inches over the wood surface covered with paper, and then drop. Typically, the stress as relieved is less than 200 lbs. The background of the glass tube is covered with white enamel and the front of the glass tube forms a magnifying glass that enlarges the liquid column and facilitates with reading the temperature.if(typeof ez_ad_units!='undefined'){ez_ad_units.push([[300,250],'instrumentationtools_com-box-4','ezslot_14',165,'0','0'])};if(typeof __ez_fad_position!='undefined'){__ez_fad_position('div-gpt-ad-instrumentationtools_com-box-4-0')}; In Below Figure (Left), an all glass thermometer is depicted, with its scale etched into the stem. While the present invention hereinafter will be described with reference to a stubby type thermometer of the monocoque variety, it is to be understood that this method can be applied equally as well to form clinical thermometers having long cylindrically shaped bulbs or a pear-shaped bulb. Indeed, a greater or smaller bulb diameter would be esthetically unacceptable. To prevent this difficulty, one must manages to get mercury thermometers inside when the temperature drops to 37C. Eliminates the hazard of splattering mercury by using a safe and easy to read red liquid. Graduated in Celsius -20 to +50 (1C) and Fahrenheit 0 to +120 (2F). The minimum distance is set at 4-1/2" (114mm). The person must shake the thermometer to get it to read below the temperature just taken. Unlike electrical thermometers, they do not necessitate power supply or batteries for charging. Moreover, due to the uniform thickness, the side wall is thicker than it would be in a conventional thermometer and, therefore, stronger while at the same time the bottom wall is thinner than it would be in a conventional thermometer and yet still is thick enough, being approximately equal to the thickness of the side wall, to resist breakage to the same degree as the side wall. Some thermometers also have a tight restriction just above the contraction chamber. When the pressurized gas is introduced into the upper end of the thermometer blank as aforesaid, the lower end of the capillary bore will cause a pocket to be formed within the hot conical downwardly tapering tip of the thermometer blank. This information can then be used to determine relative humidity and dew point. Moreover, this is accomplished without forming any external protuberances on the bulb that might irritate tender mucous membranes. When full, simply exchange SD cards for unlimited data, Related Products: Temperature And Humidity Data Logger, melting point apparatus make it safer and more accurate than a traditional mercury thermometer. 219,308 filed Jan. 20, 1972 now abandoned, for METHOD OF MAKING A CLINICAL THERMOMETER HAVING A BULB INTEGRALLY FORMED THEREWITH. How to Convert Cable Size from AWG to Inches. Resolution is 0.1% RH Accuracy is 4% RH between 35 to 75%RH, 5%RH otherwise Humidity features include dew point/wet bulb functions, minimum/maximum memory and high/low alarms Temperature range is -40 to 158F and -40 to 70C Temperature accuracy:. 3 and 4, it is basically of triangular shape with rounded corners at the back of the thermometer which is the portion wherein the strip is embedded and it also has a rounded corner at the front of the thermometer. 9. This has certain desirable effects; one is esthetic. Environmental concerns about mercury are prompting manufacturers to look for substitute materials, but many mercury thermometers are still in use. The strip extends from the upper end of the thermometer stem down into a wall of the bulb. The blank is held in upright position with a special type of jig, although this is not necessary to the practice of the invention. The liquid in glass thermometer, is the most commonly used device to measure temperature and it is inexpensive to make and easy to use. The importance of this will be pointed out subsequently. As this happens, the chuck is released and the thermometer blank may be pulled out by hand from the vise 22. The method disclosed by Chaney was used only in connection with non-clinical thermometers. The basic operations to to form the thermometer of the present invention now have been completed. High temperature portion of the thermometer can be warmed up beneath an incandescent lamp which will bring the alcohol down to the column. The bottom of the cavity is provided with a vent passageway 56 which opens to the atmosphere. The contraction chamber affords the person taking a temperature reading a little time to get an accurate reading after removing the thermometer from a heated source. 3,884,666, for CLINICAL MONOCOQUE GLASS THERMOMETER AND METHOD OF MAKING THE SAME, which is a continuation-in-part of application Ser. 2,990,648 to form bulbs on thermometer stems which bulbs were made of the same glass as the stems and, indeed, in one piece therewith. The radial outward movement of the glass quickly plugs the die cavity separating the upper portion of the cavity from the lower portion of the cavity. The bulb is typically made of glass, but some thermometers may have bulbs made of stainless steel instead. Finally, the rejects of thermometers so made were quite high, which, too, increased the expense of such thermometers as sold to the public. The contraction chamber slows the mercurys descent down the capillary. The thermometer has a straight opaque background strip embedded therein on the side of the capillary bore opposite from the lens. You can unsubscribe at any time. 6 shows the thermometer blank at the moment that the heated portion has stretched to a thin strand and is separating from the upper part of the blank, the lower end of the upper part of the blank having been formed by the heating and gravity elongation of the heated zone into a downwardly tapering conical tip in which the lower end of the bores is sealed off; FIG. workplace and environmental hazards associated with mercury. The blank has a conventional cross-section which is best shown in FIGS. In order to permit the air which initially is present in the die cavity to escape, the vent 56 has been provided. In general, if a uniform wall thickness for the side wall and bottom wall of the bulb is to be secured, it is preferred that the bulb diameter not exceed or be less than the diameter of the circumscribing cylinder by more than 20%. When 660 F. is reached, the cooling can be more rapid, for example, 100 F. per hour. 1, by tubes 32 and brackets 34, respectively. The bottom wall no longer is unusually thick to create a bull's-eye lens effect which was common in previously manufactured thermometers. 5 shows the step of heating the thermometer blank slightly above its lower end to a point where the heated zone of the blank starts to soften and elongate under the force of gravity; FIG. One can also mount the thermometer vertically for overnight which will let the drawing back of alcohol to the column. Next, the still-hot lower end, either with or without further application of heat to keep the same at a suitable temperature for deformation, is introduced into an open-topped cavity of a one-piece mold, i.e., a non-split mold. Ultimately, the strand breaks and the strand, including the portion of the former blank beneath it, drops to waste. All of the foregoing lends a highly pleasing appearance to the finished thermometer. All ranges have 1 subdivisions. document.getElementById("ak_js_1").setAttribute("value",(new Date()).getTime()); Temperature Transmitter Preventive Maintenance, Thermowell Installation near Critical Equipment. Therefore, they must be handled with extra care because they are likely to break. The rounded front corner of the thermometer blank enters between the pins 23, 24 and the side walls of the blank cam apart the pins as the blank enters the slot 26. He holds a bachelor's degree from the University of Arkansas. How to Size a Cable for Industrial AC Motors? 10 is a sectional view taken substantially along the line 10--10 of FIG. The stem was made from standard Corning lead thermometer glass and the bulb was made from a different type of material which was dimensionally stable upon stress relief at room temperature. Materials, such as alcohol, cling to the inside of glass containers, which can influence repeated temperature readings. As compared to electrical thermometers, they are very weak and delicate. The outer surface of the bulb is free from irregularities such as flash and preferably is cylindrical as in a clinical thermometer with a stubby cylindrical bulb or a long cylindrical bulb. Contains red organic liquid against white back glass. Records data onto standard SD memory cards (like a digital camera). The expansion chamber is a small widening of the capillary on the end opposite the bulb, and it provides the necessary space. The stem never was marked, as was conventional with a clinical thermometer, either with recessed markings or stain markings. This type of vise also facilitates easy loading of the thermometer blank into and unloading of the thermometer blank from the chuck 18. It is approximately 5 inches long. Related Products: Non Mercury Thermometer. The unit has an easy-adjusting check nut and has a 5-1/8" (130mm) maximum distance from center of muff to the hook. However, the apex of the conical tip is spaced from the bottom wall of the die cavity by an amount suitable to locate the finished bulb properly, i.e., in its desired position with respect to the triangular part of the thermometer blank. It will be observed that if the die cavity did not confine the bulb as it was being expanded, it would form a ball, and the thickness of the wall would not be uniform as it is with the confining restraint exercised by the aforesaid die cavity. In addition, the apparatus to form the aforesaid steps was relatively expensive and the process for operating the apparatus was expensive and required the use of skilled help, thus increasing the price of the thermometer. These thermometers display temperature either in Celsius or Fahrenheit scales. The clinical monocoque glass thermometer of the present invention is formed by a method which includes making a thermometer by starting with a glass blank. Thereafter, the thermometer is cooled slowly to room temperature, for example, at a rate of 50 F. per hour. solidification point of 61.1C. Attention also is directed to the fact that the position of the apex of the tip 45 is above the bottom of the cavity 51. This causes the still-hot lower downwardly tapered conical end of the blank to expand so as to form a bulb having a hollow interior and an external surface which engages the walls of the die cavity. The principle used to measure temperature is that of the apparent thermal expansion of the liquid. 5 and 6, the lower end of the capillary bore is just slightly below the triangular section and actually is slightly into the circular cross-section of the downwardly tapering conical tip 45. The column is intermittently rotated so as to intermittently move thermometer blanks 10 in relation to the stationary support disc 36. Omega Engineering: Introduction to Glass Thermometers, Purdue University: Mercury Thermometers FAQ. The block is positioned behind a protective screen, which speeds heating and, Related Products: Melting Point Apparatus, Thomas Scientific 2022 All Rights Reserved. Pursuant to the patent, the thermometer blank was held upright and the top portion heated to flow temperature of the glass. How to Explain Simple Vs. Free Instrumentation Course for Trainee Engineers, Single Push button to ON and OFF a Bulb using Ladder Logic. Several such chucks and associated vises thus are secured to the disc 30 which contitutes, in essence, a segment of a dial machine that is intermittently advanced by a Geneva drive. -. Immersion is measured from the bottom of the joint to the bottom of the bulb. 2. Whenever there is rise in temperature, the nitrogen gas filled above the mercury in glass tube usually comes down the column and gets stuck there. Mercury does not cling to glass, and it expands and contracts at a predictable rate. Referring now in detail to the apparatus shown in FIG. However, this area can be left evacuated too. In the prior art it has been conventional to form clinical glass thermometers by fusing to the bottom of the stem a previously formed bulb of thin section in suitable configuration. In this patent the bulb of the finished thermometer was in one piece with the glass of the stem. Accordingly, two such sets of gas jets 50 will be seen in FIG. Here, too, two dies are illustrated inasmuch as in the machine shown blanks are being operated upon in pairs. In either event, the cavity 51 is of a uniform circular cross-section, except for the bottom which is rounded and concave to impart a convex-configuration to the lower end of the bulb. Due to this particular method of applying heat and allowing the scrap to drop away, the lower end of the thermometer blank is formed into a downwardly tapered conical shape and, at the same time, the heat causes the capillary bore normally present in a clinical thermometer blank to close, sealing the lower end of the bore. Still further, this method did not provide a desired smooth shape for the extreme tip of the bulb. NOTE: The 14/20 size accepts a 1 immersion 7/12 or 10/18 thermometer, while the, Related Products: Short Path Distillation Head, totally enclosed.This head maintains reflux ratio constant with changing throughput. After the tip 45 has been so formed, the blank 10 is moved i.e., indexed, to another position relative to the stationary disc 36. The first has a relatively long and cylindrical shaped bulb and is known as the oral type. The disc 30 is attached to a supporting column 35. per square inch. Instructions, High-impact, plastic case serves as a pivoted handle in use Wet and dry bulb thermometers, range 20 to 120F in 1 divisions Swivel-mount assures that the whirling thermometers always face air flow. This pocket ultimately will become the interior of the bulb of the finished thermometer. 11) and there heated and annealed and slowly cooled to leave a negligible residual stress which in the thermometer art is considered to be essentially absent. The pins are spring-loaded to an outwardly extending position, but upon being thus cammed in, easily yield to permit entrance of the thermometer blank into and full seating of the blank upon the side walls of the slot 26, after which the pins snap back out again to the position shown in FIG. In this method, however, the rotation of the stem and of the rotary dies cuased the opaque strip against which the mercury column was to be read to be severely twisted resulting in an unsightly spiral within the bulb. 4 is an enlarged view of the thermometer blank and spring-loaded pins shown in FIG. Alternatively, the bulb was rotated with non-cylindrical dies to provide bulbs of different shapes. Following are the major advantages associated with the use of liquid-in-glass thermometers: Use of liquid-in-glass thermometers includes following limitations too: There are two major types ofLiquid-in-glass thermometerswhich are mentioned below: This type of thermometer was developed by a German based physicist namedDaniel Gabriel Fahrenheit. The thermometers mount on a wooden handle so they can be spun to obtain tem, Kit is a simple hygrometer used in measuring the moisture content in the air. Robert Korpella has been writing professionally since 2000. This strip is quite well known in the art, being employed as a background against which to read the height of the mercury column in the capillary bore 12 after the bulb has been inserted into a body cavity which causes the mercury in the bulb to expand and rise in the bore. However, it is sufficiently light to prevent breaking the glass blank. 11 is a schematic diagram of a heating, annealing and cooling chamber. This whole action may affect the functioning of thermometer. The chuck 18 clamps or grips the upper end 16 of the thermometer blank 10 with a force that is sufficient to prevent the blank 10 from falling downwardly. Conventionally, the three sides of the thermometer essentially are flat. The lower part of the triangular stem also is within the cavity. As temperatures increase, mercury moves out of the bulbs reservoir. Gases and air inside the capillary must have a place to collect as mercury rises. The chuck 18 and the vise 22 are attached to the undersurface of a rotatable disc 30, shown in FIG. 1) which uniformly) heat the conical tip 45 maintaining it as flow temperature. Attention is called to the fact that the diameter of the circular cavity 51 is somewhat larger than the imaginary circumscribing cylinder for the therometer blank. Tapered bulb condenser increases capacity without choking. The heated portion of the blank generally is subjected to the action of the burners for approximately 2 to 3 seconds. It will be appreciated that the blank can be inserted into the vise first while the upper end of the blank is below the chuck, and that after the blank has been placed in the vise it can be moved longitudinally upwardly to engage the chuck. As can be readily seen in FIG. However, because the tip is of conical configuration, it already has reached the angle of repose of the glass under the influence of gravity at the aforesaid temperature and will not flow any further. Korpella's work has appeared in a variety of publications. Mercury thermometers provide accurate, repeatable temperature readings from -40 degrees Celsius (which is also -40 degrees Fahrenheit) to 650 degrees Celsius (1202 degrees Fahrenheit). It consists of mercury as a liquid filled in a glass tube. Related Products: Mercury Filled Thermometer, Red Spirit Filled In Enclosed and Armor Aluminum Cases Aluminum Cases have Pocket Clips Length 6" (155mm) Permanent Markings Toughened Bulbs Total Immersion Thermometers Replacable, Related Products: Total Immersion Thermometer, Use this simple apparatus to measure relative humidity. The viewing cover can be removed to easily clean and change the bulb. In other words, the tip will be expanded to the shape of a bulb with a hollow interior, the exterior surface of the bulb filling the empty portion of the die cavity which is below the tip prior to inflation. Clinical thermometers so made had a high reject rate which was caused from internal undercuts that arose from misalignment of the walls of the stem and the bulb. Then pressurized gas is introduced into the still-open top end of the capillary bore of the blank. Temperature readings should be noted immediately after removal because a glass thermometer can be affected by the environmental temperature, heat produced by the hand holding it, cleaning, etc. If the bulb diameter were smaller than indicated, the graduations would be too close together to read and, moreover, the wall thicknesses no longer would be substantially uniform, i.e., the side and bottom wall thickness would vary too greatly from each other. as grooves, threads or mouths by blowing, Thermometers specially adapted for specific purposes, Clinical contact thermometers for use with humans or animals, Measuring temperature based on the expansion or contraction of a material the material being a liquid with provision for expansion indicating over not more than a few degrees, GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS, TECHNICAL SUBJECTS COVERED BY FORMER USPC, TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS, Method of making a clinical monocoque glass thermometer, Thermometer and method for its manufacture, Thermometer bubble pressing and blowing machine, Overflow machine is again used in mercury clinical thermometer production, Method of and apparatus for making tubing, Glass syringe barrel forming method and machine, Method and device for the production of foreign body-free glass vessels, in particular ampoules, injection bottles and the like. Small amounts of alcohol may cling to the portion of the capillary tube above the alcohol column.. No. 1. When spun around on their wooden handle, the wet bulb thermometer and the dry bulb thermometer will read different temperatures. A scale scribed on the outside of the stem gives the temperature reading. Alcohol, being a volatile substance may result in parting of the column in the thermometer due to mechanical shock. It is heated approximately 1/2 inches from the lower end 38 thereof (see FIG. A clinical glass thermometer having a stem of triangular cross-section, a capillary bore extending lengthwise within said stem, an opaque strip embedded within said stem and extending longitudinally thereof, and a bulb of circular cross-section, said bulb having side walls and a bottom wall formed integrally with said stem from a single piece of glass, a portion of said opaque strip extending into a side wall of said bulb, said portion of said strip in said side wall being a straight continuation of the balance of said strip in said stem, said side walls of said bulb having a thickness approximately equal to the thickness of said bottom wall, said side walls of said bulb joining said stem with no abrupt reduction of wall thickness.
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