US2673270A - Fire alarm - Google Patents

Description

March 23 MASAAKI MANPOH FIRE ALARM Filed Nov. 18, 1952 FIG.3

INVENTOR MASAAKI MANPOH ATTORNEY Patented Mar. 23, 1954 FIRE ALARM Masaaki Manpoh, Kyoto, Japan, assignor to Hunt Manpoh and Company, Klondike, Tex., a

partnership Application November 18, 1952, Serial No. 321,113

12 Claims. 1

This invention relates to signals and more particularly to a fire alarm which will operate upon exposure to a sudden increase in temperature or to a predetermined temperature being reached.

The alarm is of the type which utilizes an increase in air pressure within a confined space to raise the level of a conducting liquid such as mercury to bridge the gap between a pair of conductors in circuit with the source of power and an indicator such as a bell. The alarm also includes a second supply of mercury in a bulb and tube, similar to a thermometer, with electrical contacts spaced alongthe tube in parallel with the conductors. A rapid temperature rise will move the mercury to close the gap between contacts, thus closing the circuit; or if the rate of ise is relatively gradual, upon a predetermined temperature being reached the circuit will be closed in any event by the thermometerdike device.

Devices of this general character have been used heretofore but have lacked certain features embodied in the device of this invention, such as: a relatively large confined volume of air to afford greater sensitivity; the absence of any movable parts other than the liquid itself in order to prevent failure of operation due to sticking of such parts; the carrying of the mercury in a compact self-contained unit in order that easy access may be afforded to the remainder of the device without disturbing or losing any of the mercury; ready access to the conductor in the mercury bowl so that it may be easily installed, removed or adjusted; and means for compensating for a gradual increase in temperature below the predetermined limit so that the alarm will not be sounded due to a natural temperature rise.

Accordingly, it is an object of the present invention to provide an alarm which is operative either or both upon an excessive rate of temperature rise or upon the attainment of a predetermined temperature.

A further object is to provide an alarm which has no movable parts other than the mercury to interfere with its operation.

A further object is to provide a compact alarm designed for maximum sensitivity and easily ad- J'ustability to operate upon exposure to predetermined conditions.

These and other objects of the invention will become apparent from the following description in conjunction with the accompanying drawing, in which:

Fig. l is a top plan view of a device constructed in accordance with the invention;

2 Fig. 2, a vertical section on the line 2-2 of Fig. l; and

Fig. 3, a vertical section on the line 3-3 of Fig. 1.

Briefly stated, the device includes an inner enclosed chamber with a bowl of mercury in a lower cup-shaped portion thereof into which one electrical conductor normally extends, a second conductor normally being slightly above the mercury level. An outer chamber is formed by a cover spaced from the walls of the inner chamber. Upon an increase in temperature air within the outer chamber expands and flows into the air space above the bowl of mercury in the inner chamber, forcing the level upwardly toward the conductor which is normally out of contact with the mercury. The conductors are in parallel with a pair of spaced contacts on a thermometer-like element, leads going therefrom to a source of power and an indicator such as a bell or signal light (the latter two elements being of conventional construction and therefore not shown in the drawing).

Referring more particularly to the drawing, the alarm includes an annular collar [0 having a pair of inset portions H and I2 for the reception of apertured inserts l3 and M by means of which the device may be suspended from the ceiling by suitable fastening means (not shown). The collar H) has a tapered or substantially frustoconical pair of spaced side walls l5 extending down to an internal rim IS, the walls extending slightly upwardly from the portion I6 and being spaced apart to receive a plurality of inserts it for the reception of fastening means l9. Mounted on the shoulders I1 formed by upwardly extending portions of the rim l6 are, seriatim, a rim 20 of a cover 2|, a rim 22 of a bowl 23, and a rim 24 of a base 25.

The base 25 is of non-conducting material such as rubber or any of various plastics, all well known to the art. The base is of substantially circular or disc-like configuration and has a hub 26 which extends from one side thereof downwardly when the device is supported in normal position. The hub has a central bore 21 with an enlarged countersunk portion 28 adjacent to the upper face of the base. The hub also has a shoulder or offset portion 29 at one side thereof.

A conductor plate 30 extends across the bore 21 in the hub and over the lower surface of the shoulder 29. The portion of the plate 3d that is centrally within the bore 21 has a threaded aperture 3! which receives a bolt 32 from the end of which a conductor rod 33 extends downwardly. A lock nut 34 is mounted on the bolt in order that the latter may be secured in any desired position.

A binding post 35 is preferably molded into the base 25 and has a groove 36 at its lower end in engagement with the conductor plate 38. The upper portion of the binding post receives a. tap bolt 31 for securing the lead 38 of a conductor 38 thereto.

An end plate 4| is fastened to the lower extremity of the hub 26 by means of fasteners 42" threadedl'r received by inserts 43 in the lower;

portion of the hub. The central portion of the end plate 4i has an aperture 44 sufficiently large for the conductor rod 32 to pass through without contacting the end plate.

Also connected to the lowerportion of the end of the hub and beneath end plate 4| is-a. cylinder 46 of conducting material. The cylinder has a first relatively thin rim 4'! at its upper extremity by means of which it is attached to the hub 26 and a second relativelv thick rim orshoulder 48 spaced therefrom; the periphery of the shoulder 48 desirably seating upon a shoulder 48 formed in the bowl 23. The outer wall of the lower end of the cylinder preferably has a bevel 58.

Attached to the outer portion of the shoulder 48 is a conductor bar whose other end is received in a groove 52at the lower end of a binding post 53 (Fig. 3). The binding post 53 is received in the hub of the base similar to binding post 35, is spaced therefrom, and rccei'es a tap bolt 54 by means of which a lead 55 of a conductor 56 is attachedthereto.

The bowl 23 has a skirt 51, the lower edge portion 58 of which, remotefrom the rim 22, is imbedded or otherwise attached to a relatively thick upper wall portion 59 of nonconducting material of the bowl 23. The dome has a lower relatively narrow and extended apex forming a cup 6| for the rece tion of me cury or other suitable conducting liquid 62. The upper wall portion of the bowl has an inlet o ening "l3 which extend throu h a pro ection 64 on the upper side of the wall ortion 59. A valve member 65 has a guide rod 66 extending therethrough and into the air opening 63. The valve member has a sleeve within which a core of porous material is carried. The val e member is stationar but permits slow air movement, or seepage, through the opening 63 due to its porosity. Other valve structure for accom lishing the purpose may be sub tituted if deured.

The w lls of the co er 2| are spaced from the bowl 59 in order to ro ide su st nt l r so e 68 bet een the er -e nd the l. The o er is nreferahlv of a material of high conducti 'it such as co er and m ha e a closure or name pl te at it a e" i desired.

F om the u er ort on of the cu 6' a h "keoe ll of the do"e h n ir ssage 68 or viding communication between the s ace 68 within the cover 2! and the space over the me curv h ch i" out-ide of the w ll of the cylinder 46. The passage may e lugged with norous. substance such as cotton 61 which will permit air flow but will ore'ent loss of the me cury therethrough in the event that the device is inverted or shaken.

Mounted on the up er surface of the periphery of the base is a tem erature responsive element 12. The element is similar to a conventional mercury type thermometer and has a bulb 13 at its lower end connected to an elongated tube 14. The tube hasa bore in which the. mercury from the bulb may rise in proportion to the surrounding temperature. The tube 14 is supported on the base at spaced intervals by clips 75, 16, and suitable fastening means 11 extending therethrough into the base. Conductors 18 and 18 extend from the fastening means TI to contacts 86. and 8| extending into the bore of the tube. Suitable leads 83 and 84 are connected to the conductors l8 and 19 respectively. The binding posts 35 and 53 may be connected in parallel with the conductors l8 and 19 by leads 93 and 94.

The countersunk portion 28 of the bore 21 extending through the hub 26 of the base is normally covered by an end member 86 which snaps into. the opening and. is retained by a rim on its lower end which engages a groove in the bore.

A leaf 88 normally covers the end member 86. The leaf 86, is of springy material and is attached to the base bya foot portion 88 through which a fastener 8!) extends into an insert 9| in the: base. The free end of the leaf may be fastened by a conventional wire and lead seal (not shown) to prevent unauthorized tampering with the adjustment of theconductor rod 33.

In order to obtain maximum benefit from the device it is suspended or positioned in an onclosed space and preferably near the ceiling or adiacent to a location in which fire may develop which it is de ired to detect. In the event of. fire the heat therefrom, including heated air currents, contacts the outer face of the cover 2| and is transferred to the air in the space "within the cover 2| between it and thebowl 23. The. increase in pressure resulting from the sudden: temperature rise is communicated by passage 68 to the space above the mercury on the. outside: of cylinder 46, forcing the mercury downwardly and raising the level within the cvlinder to the contact rod 33. Flow of air through the vale member 65 is too slow to materially relieve or aifect the pre sure within space 68 under such condition From the cylinder 46 thecircuit is com leted through conductor bar 5|, binding post 53 and conductor 56. From the rod 33 the circuit is c m lete'i throu h bowl 2, late 38,, From the binding cost 35, and conductor 38. binding ost "5 and 5? the circuit may be comnlete'l. thrrugh the- c nductors 83, 84 attached to the f stening means 11, or if preferred, a direct connection may be made through the conductors P9. 56 t the other element of the circuit (not:

shown) including a source of power and an indi to" Should the temperature rise be gradual the pressure in space 68 is relieved or offset by air seepa e through valve 65 into the space between a predetermined maximum or the rate increases.

beyond a compensatable limit.

Regardless of the rate of rise when apredetermined temperature is reached the mercury in the tube 12 will bridge the gap between conductors 18 and 19 to close the: circuit and operate the indicator element.

From the foregoing t will be understood that the embodiment of the invention includes a rate of rise circuit closer operated by an increase in air pressure within a confined space, and a thermometer-like element in parallel with the rate of rise closer which is operative to close the circuit when a predetermined temperature is reached, thus completing the circuit by either or both means to conventional indicator elements which may be positioned either adjacent to or remote from the device itself.

It will be understood by those skilled in the art that the invention is not limited to the particular embodiment disclosed but that reasonable variations therefrom are within the scope of the invention and that the invention is therefore only limited as described in the following claims.

What is claimed is:

1. A fire alarm comprising an annular collar, mounting means in said collar, a base of nonconducting material mounted in said collar, said base having a hub projecting from one side thereof, said hub having an offset portion and a bore, a conductor plate within said hub and extending across said bore, a first binding post mounted in the offset portion of the hub and attached to said plate, an elongated contact member adjustably connected to said plate and within said bore and extending beyond said hub on the same side of the base as said hub, an end plate connected to said hub, said end plate having an aperture through which said contact member passes, a cylinder connected to said hub and forming an extens on thereof, said cylinder having a rim at its base by which the cylinder is attached to the hub, said cylinder having a second rim intermediate its ends, a bowl spaced from the hub and cylinder and enclosing a first air space and having a rim attached to the periphery of the base, the bowl having a skirt portion of conducting material attached to a dome of non-conducting material, the dome having a narrow extended apex forming a own, the cylinder being mounted within the bowl with its second rim resting on the dome and having its end remote from its base extending into the cup, a second binding post mounted in the offset portion of said hub, conductor means extending from said second binding post to said second rim, a supply of conducting liquid partially filling the cup, a cover having a rim connected to the periphery of said base and enclosing'a second air space between it and said bowl; said bowl having means for permitting relatively slow air leakage from said second air space to said first air space, and said cup having means for permitting relatively rapid air movement from said second air space into the upper portion of said cup but preventing the flow of mercury therethrough.

2. A fire alarm comprising an annular collar, a base of non-conducting material mounted in said collar, said base having a hub projecting from one side thereof, said hub having a bore, conductor means within said hub and extending across said bore, a first bind ng post mounted in the hub and attached to said plate, an elongated contact member. adjustably connected to said plate and within said bore and extending beyond said hub, an end plate connected to said hub, said end plate having an aperture through which said contact member passes, a cylinder connected to said hub and forming an extension thereof, said cylinder having a rim at its base by which the cylinder is attached to the hub,

said cylinder having a second rim intermediate its ends, a bowl spaced from the hub and cylinder and enclosing a first air space, the bowl having a skirt portion of conducting material attached to a dome of non-conducting material,

the dome having a narrow extended apex forming a cup, the cylinder being mounted within the bowl with its second rim resting on the dome and having its end remote from its base extending into the cup, a second binding post mounted in the offset portion of said hub, conductor means extending from said second binding post to said second rim, a supply of conducting liquid partially filling the cup, a cover having a rim connected to the periphery of said base and enclosing a second air space between it and said bowl, said bowl having means for permitting relatively slow air leakage from said second air space to said first air space, and said cup having means for permitting relatively rapid air movement from said second air space into the upper portion of said cup but preventing the flow of mercury therethrough.

3. A fire alarm comprising a base of non-conducting material, said base having a hub project ing from one side thereof, said hub having a bore, a conductor plate within said hub and extending into said bore, a first binding post mounted on the base and connected to said plate, an elongated contact member adjustably connected to said plate and within said bore and extending beyond said hub, an end plate connected to said hub, said end plate having an aperture through which said contact member passes, a cylinder connected to said hub and forming an extension thereof, said cylinder having a rim intermediate its ends, a bowl spaced from the hub and cylinder and enclosing a first air space, the dome having a narrow extended apex forming a cup, the cylinder being mounted within the bowl with its rim resting on the dome and having its end remote from its base extending into the cup, a second binding post mounted on the base, conductor means extending from said second binding post to said rim, a supply of conducting liquid partially filling the cup, and a cover connected to said base and enclosing a second air space between it and said bowl, said bowl having means for permitting relatively slow air leakage from said second air space to said first air space, and said cup having means for permitting relatively rapid air movement from said second air space into the upper portion of said cup but preventing the flow of mercury therethrough.

4. A fire alarm comprising a base of non-conducting material, said base having a hub projecting from one side thereof, said hub having a bore, a conductor plate extending into said bore, a first binding post mounted on the baseand connected to said plate, an elongated contact member connected to said plate and within said bore and extending beyond said hub, a cylinder connected to said hub and forming an extension thereof, said cylinder having a shoulder intermediate its ends, a bowl spaced from the hub and cylinder and en-- closing a first air space, the dome having an apex forming a cup, the cylinder being mounted within the bowl with its shoulder resting on the dome and having its end remote from its base extending into the cup, a second binding post mounted on the base, conductor means extending from said second binding post to said shoulder, a supply of conducting liquid partially filling the cup, and a cover connected to said base and enclosing a second air space between it and said bowl, said bowl having; means for permitting relatively slowair. leakage from said second air space to said first air space, and said cup having means for permitting relatively rapid air movement from said secand air space into the upper portion of said cup but preventing the flow of mercury therethrough.

5. A maximum temperature and temperature rate of rise responsive circuit closer comprising a base, a bowl attached to said base and having an enclosed cup for aliquid conductor, wall means in said cup separating the air space above the conductor, a conductor element on one side of said wall means, a second bowl spaced from and housing the first bowl, means for permitting air between it and the first bowl to slowly flow into the space between the first bowl and the base, means for permitting air between the second bowl and the first bowl to rapidly flow into the air space above said conductor on the side of said wall means opposite the conductor element, first and second conductor means leading to the conductor element and the wall means respectively, a bulb of mercury, an elongated tube attached to the bulb, spaced contact means along the tube and adapted to contact mercury therein, and means connecting said first and second conductor means to said contacts.

6. A temperature rate of rise responsive circuit closer comprising a base, a bowl attached to said base and having an enclosed cup for a liquid conductor, wall means in said cup separating the air space above the conductor, a conductor element on one side of said wall means, a second bowl spaced from and housing the first bowl, means for permitting air between it and the first bowl to seep into the space between the first bowl and the base, means for permitting air between the second bowl and the first bowl to rapidly flow into the air space above said conductor on the side of said wall means opposite the conductor element, and first and second conductor means leading to the conductor element and the wall means respectively.

7. A temperature rate of rise responsive circuit closer comprising a base, a bowl attached to said base, and having an enclosed cup for a liquid conductor, wall means in said cup separating the air space above the conductor, a conductor element on one side of said wall means, a second bowl spaced from and housing the first bowl, means for permitting the slow relief of pressure of the air between the first bowl and the second bowl, means for permitting air between the second bowl and the first bowl to rapidly flow into the air space above said conductor on the side of said wall means opposite the conductor element, and first and second conductor means leading to the conductor element and the wall means respectively.

8. A fire alarm comprising a base of non-conducting material, a first bowl attached to the base and enclosing a first air space between it and the base, a second bowl attached to the base and enclosing a second air space between it and the first bowl, means defining a third air space between the first and second bowls, a supply of mercury partially filling the third air space, wall means extending from the first bowl into the third air space and into the mercury, a conductor supported on one side of said wall means and normally spaced above the. mercury, means tor permitting air to flow fromsaid second air space to said third air space above the mercury and on the side of the wall opposite the conductor, conductor means extending from said conductor to a first contact, and second conductor means extending from said wall means to a second contact.

9. The structure of claim 8, and means permitting the slow relief of pressure from the second air space to the first air space.

10. The structure of claim 9, a. bulb of mercury, an elongated tube attached to the bulb, spaced contact means along the tube and adapted to contactv mercury therein, and means connecting said first and second. contacts in parallel with said spaced contact means.

11. A temperature rate of rise responsive. circuit closer comprising a cup for a liquid conductor,,wal1 means in said cup separating, the air space abovev the. conductor, a conductor element on one side of said, wall means, a wall extending outwardly from said cup, rim means at the outer edge of said wall, a base enclosing the air space above the wall, said wall preventing the passage of. air therethrough, bowl means spaced from and substantially housing, the wall, means for permitting air between the wall and the bowl to rapidly flow into the air space above said conductor on the side of said wall means opposite the conductor element, means for permitting the slow relief of. pressure of the air between the wall and the bowl, and first and second conductor means leading to the conductor element and the wall means respectively.

12. A temperature rate of rise responsive cir cuit closer comprising a cup for a liquid conductor, wall. means in said cup separating the air space above the conductor, a conductor element on one side of said wall means, a wall extending outwardly from said. cup, a base enclosing the air space above the wall, said wall preventing the passage of air therethrough, bowl means spaced from and substantially housing the wall, means for permitting air between the wall and the bowl to rapidly flow into the air space above said conductor on the side of said wall means opposite the conductor element, means for ofisetting a slow increase in pressure of the air between the wall and the bowl, said means comprising means permitting air to seep from the space between the bowl and the wall to the space between the wall and the base, and air passage means from said last mentioned space to: the air space above a said liquid conductor. andon the side of said wall means adjacent to said conductor element. MASAAKI MANPOH.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date Re. 22,012 Weaver et al Jan. 20', 1942 887,157 Walther May 12, 1908 1,605,020 Woodbridge Nov. 2, 1926 2,150,053 Chilowsky Mar. 7, 1939 2,169,088 Carter Aug. 8, 1939 2,318,480 Griffith May 4, 1943 2,611,057 Slonneger Sept. 16, 1952

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