US1943480A - Automatic sprinkler - Google Patents

Description

Jan. 16, 1934.

W. K. HODGMAN, JR

AUTOMATIC SPRINKLER Filed Sept. 16, 1932 Ammo 1 I F \nvenTor. \/\/i|\is KHodgmcn \Jr.

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. Patented Jan. 16, 1934 PATENT," OFFICE AUTOMATIC SPRINKLER Willis K. Hodgman, Jr., Taunton, Mass.

Application September 16, 1932 Serial No. 633,488

12 Claims.

This invention relates to a frangible vessel and more particularly to an automatic sprinkler employing such a frangible vessel as a strut or means for normally holding the sprinkler closed.

In this type of device the vessel usually made of glass or similar material contains an expansible fluid designed, when the temperature surrounding the'vessel reaches a predetermined degree, to expand and burst the vessel, thus destroying its function as a strut and effecting the opening of the sprinkler head. This type of device is highly desirable wherever the conditions are such as to interfere with the accuracy and eificiency of operation of the usual type of sprinkler head employing fusible metal struts or operating members held together or in position by fusible metal. The type of sprinkler head operating member to which this invention relates is not subject to corrosive action of gases, fumes, or other impurities frequently existing in manufacturing plants or other places where sprinkler systems are installed.

In this type of sprinkler head it is obvious that the expansible fluid must be maintained indefinitely unchanged both in amount and in quality, otherwise the accuracy of operation of the sprinkler head would be impaired. This result has heretofore been solved by sealing by fusion the glass vessel containing the expansible fluid. But fusion requires the application of a high temperature which prevents the annealing of the glass, sets up internal strains in the glass, or requires the vessel to be made of highly specialized material. Furthermore, the heat of fusion has its effect upon the expansible fluid itself, thus requiring extremely careful manipulation and designing of the vessel.

The present invention has for its object to provide a frangible vessel of non-corrosive material, preferably glass, in which the open end of the vessel is closed and tightly sealed by a'st0pper,'

also of non-corrosive material and preferably of the same material as the vessel.

The object of the invention is further to provide such a construction in which the stopper is held seated on the open end of the vessel with the joint between the two transmitting substantially the entire pressure, exerted longitudinally of the vessel and stopper, in a direction normal to the joint. Consequently the heavy pressure, such as required in a sprinkler strut, presents no deleterious resultants acting to split apart or to contract the walls of the vessel. I

Theobject of the invention is further to provide a frangible vessel of this type which may thus be filled with the expansible fluid, sealed without the use of heat, and installed in position as a sprinkler strut or for other purposes.

The object of the invention is further to provide such a device in which the frangible vessel may be made of a homogeneous material, such as annealed glass, having uniform characteristics throughout and not possessing any deleterious internal strains. Thus uniformity in manufacture is readily and economically attained. Thus also the required characteristic reactions of the vessel when bursting temperature has been reached are uniform and reliable.

These and other objects and features of the invention will appear more fully from the accom-' panying description and drawing and will be particularly pointed out in the claims.

In the drawing:

Fig. 1 is an elevation of a sprinkler head em- I bodying a preferred form of the invention;

Fig. 2 is a detail enlarged in vertical cross section of a portion of the construction shown in Fig. 1;

Fig. 3 is a detail partially broken away to illus- The invention is here illustrated in a preferred form as applied to an automatic sprinkler head. A sprinkler head of a familiar type is shown in which the base 1 is threaded at 2 for attachment to the sprinkler system. This base presents at its upper end a mouth or opening 3 through which the water is discharged. From the base and rigid therewith rises an arch 4. A screw 5 is threaded into the arch in alignment with the mouth of the base and upon this screw is mounted the usual deflector 6. The mouth of the base is closed by a cover 7, preferably made of metal, and a gasket 8 of soft metal, such as copper, is preferably interposed between the cover 7, and the mouth of the base.

The strut, to which this invention particularly relates, is interposed between the screw 5 and the cover 7 and as usual acts normally to hold the cover in place against the pressure of the water and thus prevent any discharge of the water until the strut is removed.

The strut, as shown, comprises the vessel 9, the stopper 10, the cap 11 and the spacer 12.

The vessel 9 is formed of frangible non-corrosive material and for that purpose homogeneous, annealed glass is preferable, such glass, for example, as commonly employed for oven wear is efficient. The glass vessel 9 is formed into the required shape by any of the usual processes, such as molding or blowing and desirably presents a relatively thin walled globular body 13 and a relatively thick walled tubular neck 14 having a relatively small opening 15 therethrough. The open end of this bottle-shaped vessel is ground or finished off flat. The stopper 10 is also made of non-corrosive material and preferably of the same material as the vessel and is desirably of disk shape and in any event has its surface opposed to the end of the bottle neck also finished or ground flat so thatit may contact evenly and directly and tightly with the end of the bottle neck thus hermetically sealing the vessel.

The cap 11 which is made of rigid material and preferably of metal fits over the stopper and presents an extended surface conforming to the top surface of the stopper. This cap also presents a peripheral flange l6, surrounding, spaced from, and protecting the joint between the stopper and bottle neck end. The cap 11 directly engages the screw 5 and for that purpose may be provided with a projection 17 seating in a corresponding recess in the end of the screw 5.

The lower end of the globular body 13 of the vessel is seated on the cover 7. When the vessel is formed by molding or so as to present a highly accurate shape, it may seat directly in a recess in the cover '7. If, for any reason, the globular body is slightly irregular, the cover may have connected therewith or embodied therein a cradle of resilient material as shown at 18 in Fig. 4 to receive and conform to and present an even bearing seat for the base of the globular body.

The frangible vessel may be filled with any suitable fluid, which has a low freezing point and which will act to expand and burst the vessel at the predetermined or required temperature. It may be entirely or partially filled as required by inserting a measured quantity of the fluid. A simple way of filling the vessel is first to fill it with the fluid, then immerse the vessel in water with the open end above the level of the water, then raise the water to the temperature at which the sprinkler head is to operate and maintain it at this temperature until the fluid has ceased to overflow and the surface of the end of the neck of the vessel is dry. The bottle is then removed from the water and allowed to assume room temperature. The stopper is then placed in position and the strut assembled. This leaves the neck of the bottle filled with air as shown in Fig. 2. With this arrangement, when heat, as in the case of a fire, is applied to the sprinkler head, the fluid expands until, at the bursting temperature, the air in the vessel is highly compressed and immediately the expansion of the liquid bursts the vessel and the expanding air breaks it into fragments, shattering the glass and removing the strut entirely out of the way.

With the sprinkler head assembled as shown in Fig. 2, the screw 5 is turned down until the strut is under the requisite pressure to offset the pressure of the water in the system, together with a considerable factor of safety, and prevent the water from issuing from the mouth 3 when the strut is in place. When in this position, the screw 5 is usually fastened in place by the pin 19.

It will be seen in the preferred form of the invention illustrated that the pressure exerted longitudinally of the strut is transmitted through the rigid cap 11 to the stopper 10 and that with the spacer 12, which is preferably of some resilient material such as a thin disk of lead, ensures the even distribution of this pressure. Thus the stopper is forced and held squarely and firmly against the end of the bottle neck. But as the opposed surfaces of the stopper and bottle neck are flat the pressure exerted is normal to the joint between the stopper and bottle neck throughout so that there are no deleterious resultants of the pressure acting either to split the bottle apart or to contract the walls of the bottle, that is, the action is entirely different from that in the case, for example, of a glass stoppered medicine bottle where the stopper is forced into the mouth. of a bottle, or as in the case of a cap forced over the outside of a bottle. Not only does the transmitted pressure act as set forth, but it actswith all its force to hold the stopper and bottle neck end tightly seated together and thus prevent any possible escape of the contents of the vessel.

As afurther protection tothe joint, the surface of the bottle neck or the opposed surface of the stopper, or both, may be coated with a suitable filmy coating, shown greatly exaggerated at 20 in Fig. 2, such as sodium silicate which, in the case of glass, is peculiarly suitable. Such a coating acts to form a precautionary sealing gasket.

As a still further protection to the joint, particularly to guard it against the action of moisture or other foreign matter in the atmosphere, the space between the peripheral flange 16 of the cap 11 and the vessel may be packed with filling material 21 as illustrated in Fig. 3. An asphaltic mixture, for example, may be used for this purpose.

It will thus be seen that the device is one of extreme simplicity. It may be readily and easily constructed. Uniformity of conditions is readily obtained. The filling of the vessel with the predetermined amount of the expansible fluid is a simple matter. The assembling of the strut is also simple. No injurious and incalculable internal strains are set up in the vessel such as result from fusion. While the strut is capable of withstanding high pressure, far above that required to hold the sprinkler closed, there are no resultants from this pressure acting to split apart or contract the walls of the vessel and the pressure itself acts to ensure a tight joint between the stopper and vessel. The entire device, therefore, is unaffected by corrosive action, is highly dependable, is accurate in operation and endures indefinitely without change.

Having thus described the invention, What is claimed as new, and desired to be secured by Letters Patent, is:

1. A frangible vessel of non-corrosive material havingan open end and containing a predetermined amount of an expansible fluid; a stopper of non-corrosive material seated on, and tightly closing, the open end thereof; the joint between the vessel and the stopper transmitting substantially the entire pressure, exerted longitudinally of the vessel and stopper, in a direction normal to the joint thus to avoid deleterious resultants acting to split apart or to contract the walls of the vessel; the said fluidacting, when the stopper and vessel are thus held tightly closed by the said longitudinally exerted pressure and the temperature of the fluid has been raised to a predetermined degree, to expand, burst and scatter the vessel.

2. A homogeneous annealed glass vessel having an open end containing a predetermined amount of an expansible fluid; a glass stopper; said stopper and the open end of the vessel presenting flat ground opposed surfaces with the stopper seated on, and tightly closing, the open end; the joint between the vessel and the stopper transmitting substantially the entire pressure, exerted longitudinally of the vessel and stopper, in a direction normal to the joint thus to avoid deleterious resultants acting to split apart or to contract the walls of the vessel; the said fluid acting, when the stopper and vessel are thus held tightly closed by the said longitudinally exerted pressure and the temperature of the fluid has been raised to a predetermined degree, to expand, burst and scatter the vessel.

3. A homogeneous annealed glass vessel .and stopper having the construction defined in claim 2, together with a filmy coating between the stopper and the open end of the vessel forming a precautionary sealing gasket.

4. A homogeneous annealed glass vessel and stopper having the construction defined in claim 2, together with a coating of sodium silicate between the stopper and the open end of the vessel forming a precautionary sealing gasket.

5. A sprinkler head comprising a base having a discharge mouth; an arm extending from the base to a point opposite the mouth; a strut mounted between the arm and the mouth to maintain the mouth normally closed comprising a homogeneous annealed glass bottle having a relatively thin walled globular body and a relatively thick walled tubular neck with a single flat ground open end, a glass stopper having a fiat ground surface seating on the bottle neck end, and a cap engaging an extended surface of the stopper opposite the ground surface and acting to distribute evenly to the stopper and thence to the bottle, in a direction normal to the ground surface and end, pressure exerted on the cap longitudinally of the bottle between the arm and mouth; and a predetermined amount of a substance within the bottle acting, when the surrounding temperature has been raised to a predetermined degree, to expand and burst and scatter the bottle.

6. A sprinkler head comprising the construction defined in claim 5, together with a coating of sodium silicate between the stopper and bottle neck end forming a precautionary sealing gasket.

'7. A sprinkler head comprising the construction defined in claim 5, together with a resilient spacer between the engaging surfaces of the cap and stopper acting to distribute the pressure evenly to the stopper.

8. A sprinkler head comprising the construction defined in claim 5, together with a soft metal cushion between the engaging surfaces of the cap and stopper acting to distribute the pressure evenly to the stopper.

9. A sprinkler head comprising a base having a discharge mouth; an arm extending from the base to a point opposite the mouth; a strut mounted between the arm and the mouth to maintain the mouth normally closed comprising a homogeneous annealed glass bottle having a relatively thin walled globular body and a relatively thick walled tubular neck with a flat ground end, a stopper having a fiat surface hermetically sealing the bottle neck end, and a cap engaging an extended surface of the stopper opposite the ground surface and acting to distribute evenly to the stopper and thence to the bottle, in a direction normal to the ground surface and end, pressure exerted on the cap longitudinally of the bottle between the arm and mouth, the said cap having a peripheral flange surrounding, spaced from, and protecting the joint between the stopper and bottle neck end; and a predetermined amount of a substance within the bottle acting, when the surrounding temperature has been raised to a predetermined degree, to expand and burst and scatter the bottle.

10. A sprinkler head comprising the construction defined in claim 9 together with filling material in the space between the cap and the said joint acting to exclude moisture or other foreign matter in the atmosphere from the joint.

11. A sprinkler head having a base with a mouth for the discharge of water and an opposed arch; cover for the mouth and a strut between the cover and the arch; the said strut comprising a homogeneous annealed glass bottle having a relatively thin walled globular body and a relatively thick walled tubular neck with a fiat ground end; a glass stopper having a flat ground surface seating on the bottle neck end; a cap engaging an extended surface of the stopper opposite the ground surface and acting to distribute evenly to the stopper and thence to the bottle, in a direction normal to the ground surface and end, pressure exerted on the cap longitudinally of the bottle; the cover having a seat to receive, and conform to the base of, the globular body of the bottle; and a liquid within the bottle having a low freezing point and exerting, when raised to the predetermined operating temperature of the sprinkler head, an expansive force suflicient to burst the glass bottle of the strut and remove it from between the mouth and arch of the base.

12. A releasing device having opposed abutments; a strut between said abutments comprising a frangible vessel of non-corrosive material having an opening presenting a flat end surface and containing a predetermined amount of an expansible fluid, a stopper of non-corrosive material presenting a flat surface fitting against the fiat end surface of the vessel and hermetically closing the vessel; the said fluid acting when the stopper and vessel are held tightly closed by pressure exerted between said abutments longitudinally of the vessel and stopper and the pressure of the fluid has been raised to a predeteri" mined degree, to expand, burst and scatter the vessel.

WILLIS K. HODGMAN, JR.

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