US2095087A - Fire alarm system - Google Patents

Description

Oct. 5, 1937. .1. SIDDALL ET AL FIRE ALARM SYSTEM Filed Sept. 1, 1954 3 Sheets-Sheet l NSULATION I l l FURNAE ROOM.

ATTORNEY 0a. 5, 1937. MALL ET AL 2,095,087

FIRE ALARM SYSTEM Filed Sept. 1, 1934 3 Sheets-Sheet 2 9 INVEN RS 1 W1 gum aw J8 BY Wimgv 1937- J.v SIDDALL ET AL- 2,095,087

FIRE ALARM SYSTEM Filed Sept. 1, 1934 3 Sheets-Sheet 3 mv NT R BY M ATTOII2NEY Patented Oct. 5, 1937 UNITED STATES PATENT OFFICE aoaaoa'z' i'mn ALARM SYSTEM Joseph Slddall, Kearney, and William 1!. Siddall, Berkeley Heights, N. J.

9Claims.

This invention relates to fire and heat or temperature alarm systems of the fluid pressure so called rate-of-rise type and of the thermo-responsive electrical type. The fluid pressure type of system usually includes a loop of fire detecting tubing arranged in a zone to be protected against fire, and a signal operated by fluid pressure in the tubing caused by a rise in temperature of the fluid in the tubing, as upon the oc- 10 currence of a fire in the vicinity of the tubing.

The thermo-responsive electrical system includes a temperature responsive circuit changing device operable normally to change, open or close the circuit upon occurrence of a predetermined temperature in the vicinity of the device, and a signal controlled thereby for actuation when the circuit is changed.

In the fluid pressure or rate-'of-rise system, it is the general practice to utilize bare copper tubing and secure the tubing to the walls and ceilings of the rooms or spaces to be protected. Copper is preferable because of its ductility and bendability which enables it to be bent and pulled through openings in partitions or walls, as well as because of its high heat conductivity. 7

Such fluid pressure systems involving the use of bare copper tubing, while highly eflectual when in perfect operating condition, are subject to many disadvantages as will be pointed out hereinafter.

The prime object of our invention is to provide novel and improved means for overcoming the dlflicultles now encountered in the installation and use of such systems. I

Heretofore it has been considered necessary to utilize tubing in uncovered condition so that it shall be quickly responsive to variations of the temperature. It has therefore been impracticable to utilize the tubing as a part of an electrical circult to supervise the tubing so that a break in the tubing at any point would cause the operation of a signal to indicate a defect in the system. Where attempts have been made to so electrically supervise the tubing, the tubing has been mounted on insulators secured to the walls or ceilings.

We have discovered that it is possible to cover the tubing with electric insulation without detrimentally affecting the sensitivity of the tubing to temperaturechanges, and therefore we have discovered that it is possible practically to use the Q tubing as an electric conductor in a circuit for electrically supervising the tubing.

According to. the general, practice heretofore sive and great variations of temperature of short duration are suflicient to cause operation of the signal, even though such changes in temperature may be normal and without any incidental fire hazard. We have discovered that we may reduce 5 the possibility of occurrence of such false claims by covering the copper tubing with a heat insu-v lati'ng material, the heat insulating covering being sufficient to protect the tubing against such sudden and great changes of temperature so that 10 the temperature may quickly rise and fall before time enough has elapsed to permit'the heat to penetrate the insulation and materially affect the pressure in the tubing. In this way, and by varying the amount of insulation at different 15 points in the length of the tubing circuit, it is possible to compensate for normal substantial variations in temperatureat difl'erent points in the circuit, for example in the office of a factory building and in the boiler room of the building. 20

- Furthermore, the bare copper tubing heretofore commonly used is subject to rapid corrosion under atmospheric conditions or in installations where the tubing is contacted with gases containing chemicals which may react with the cop- 25 per. We have found that by covering the tubing with a material which is substantially resistant to atmospheric conditions and chemicals, the tubing can be protected against such corrosion.

The bare copper tubing heretofore used is also 30 inherently soft and subject to easy bending or denting during handling, and it frequently happens that in fastening the tubing to a ceiling or wall by means of a clip, as usual, the tubing is crushed or dented in such manner as to make it 35 substantially practically inoperative. Similar denting and bending may occur during pulling of the tubing in holes or partitions or bending the tubing around sharp corners, as over beams or the like. We have discovered that by covering 40 the tubing, it can be substantially protected against such denting and bending, and yet the flexibility of the tubing is substantially unimpaired.

With the use of bare copper tubing, should a 45 break or leak occur in the tubing, the escape of air from the tubing through theleak may prevent operation of the alarm system upon the occurrence of a fire, or at least retard operation of the alarm until the fire has become of such large proportions that the alarm would be futile.

We have found that by utilizing a covering for the tubing that is substantially impervious to air, should a break, crack or perforation occur in the tubing, the cover will practically sea] m break, crack or perforation and prevent the escape of air from the tubing, so that the operation of the alarm system will not be materially aiiected.

Another object of the invention is to provide a novel and improved combination of a fluid pressure system and electrical system wherein two parallel tubing sections shall be encased in a common sheath or covering of insulating material and insulated from each other, and a thermoresponsive circuit changer shall be connected across the two tubing sections so that the tubing can be electrically supervised and a signal can be operated by said circuit changer.

A further object is to provide a novel and improved combination fluid pressure system wherein the tubing shall constitute a part of an electric circuit, a manually operable normally closed circuit changer, for example a watchmans box, shall be connected in the circuit, and an electrical signal shall be provided for actuation upon opening of the circuit by either the circuit changer or a break in the tubing, sothat an alarm may be sounded, at any time, by a watchman independently of the fluid pressure signal.

Another object is to provide novel and improved encased or' sheathed metallic tubing for alarm systems.

Other objects, advantages and results of our invention will be brought out by the following description when read in connection with the accompanying drawings. v

Referring to said drawings in which corresponding and like parts are designated throughout the several views by the same reference characters,

Figure l is a schematicelevation of a fluid pressure fire alarm system embodying our invention.

Figures 2 and 3 are similar views showing modifications of the tubing insulation to compensate for difierent conditions.

Figure 4 is a sectional perspective view of a piece of the tubing showing the details of the insulation.

Figure 5 is a view similar to Figure 1 illustrating the tubing as broken and showing the manner of locating the break.

Figure 6 is a schematic elevation of another fluid pressure fire alarm system embodying our invention, showing the system as electrically supervised and including a manually operated switch for causing the sounding of the signal.

Figure 7 is a sectional view through a partition or ceiling, showing the manner of installing a tubing thereon.

Figure 8 is a fragmentary sectional perspective view of a piece of tubing showing a slit therein that is covered by the insulation.

Figure 9 is an enlarged transverse vertical sectional view through the tubing shown in Figure 8.

Figures 10 and 11 are sectional views through bare copper tubing showing the same bent and indicating deformities in the tubing as a result of bending.

Figure 12 is a similar view showing our insulated tubing.

Figure 13 is a fragmentary sectional elevation of a conduit having our insulated tubing threaded therethrough.

Figure 14 is a longitudinal sectional view through the tubing showing the manner in which the insulation protects it against blows.

Figure 15 isa similar view-showing the manner in which the insulation protects the copper tubing against rough walls in an opening through which the tubing is threaded.

Figure 16 isa transverse sectional view through bination fluid pressure and thermostatic electrical fire alarm system embodying a modification of our covered tubing.

Figure 22 is an enlarged longitudinal sectional view through the form of tubing shown in Figure 21, and

Figure 23 is a fragmentary elevation of another form of the covered tubing.

For the purpose of illustrating the principles of the invention, we have shown it schematically as embodied in a simple system generally illustrated in Figure 1. This system includes a loop of metallic tubing l, to opposite ends of which are connected fluid-pressure-responsive devices 2 of known construction, for example of the diaphragm type wherein the diaphragm is caused to flex under variations in fluid pressure. The tubing is located in a zone to be protected and upon the occurrence of a fire in the vicinity of any portion of the tubing, the air within the tubing is expanded by the heat from the fire so as to increase the pressure of the air and actuate the devices 2. As shown, the diaphragm of each fluidpressure-responsive device 2 carries an electrical contact 3 which cooperates with another contact 6 connected in circuit with a source of electricity 5 and a signal such as abell '6; andthe two devices 2 are electrically connected by a wire i, so that upon the engagement of either contact 3 with its corresponding contact a, the circuit is closed through the sighal tii operate the latter.

The fluid-pressure responsive devices 2 are connected to the tubing in insulated relation as by sleeve 8 of electric insulating material, and a suitable vent or breathing opening 9 is provided for each device to permit the fluid pressure in the tubing to become reduced to atmospheric pressure after such pressure in the tubing has been increased by heat.

In accordance With the invention, the tubing I is encased in a sheath which is preferably formed of material having both heat and electrical insulating qualities, which is resistant to corrosion and which is impervious to air. However, where it is desired only to protect the tubing against corrosion by atmospheric gases, chemicals or the like, the sheath may simply be corrosion-resistant, or where it is desired to insulate the tubing i against heat, the sheath may be of simple heatinsulating material, or where electrical insulation of the tubing only is required, the sheathmay be of electrical-insulating material. We have found that the sheath i0 may be placed upon the tubing without detrimentally afiecting the sensitivity of the tubing to changes in temperature, and the fluid-pressure-responsive devices 2 may be adjusted to operate under a given temperaturein factory building, while another portion may pass through the boiler room. In such a case the nor 7 mal temperature in the boiler room isconsiderably higher than the normal temperature in the offlce or machine shop and there normally occur sudden rises of temperature of short duration, but it is necessary that the alarm system operate upon an abnormal rise in temperature in either place. We have found that this result may be accomplished by applying to the portion oi the tubing in the boiler room or in that part of the zone having abnormally high temperatures or normal sudden rises in temperatura, a sheath of insulating material of greater thickness than the insulating material on other portions of the tubing. This is generally illustrated in Figure 2 of the drawings where the dotted lines schematically indicate the furnace room, and the extra thickness of insulation is designated Where the furnace room or part of the zone of highest temperature is located closely adjacent one of the pressure-responsive devices 2, additional thicknesses of insulation I! may be applied to the tubing as shown in Figure 3. The reason for this will be apparent to those skilled in the art, it being understood that a given rate-oi-rise of temperature will operate the signal more quickly when the temperature is applied to the tubing close to the pressure-responsive devices than when the same temperature is applied to the tubing at a point remote from the'pressure-responsive devices. It will thus be evident that different amounts or thicknesses of insulation may be applied to different portions of the tubing circuit to compensate for diflerentnormal temperatures at various points along the circuit.

The insulation may be of any suitable form, but preferably includes a layer ll of rubber directly over the tube, and layer or layers 01' fibre or woven fabric l5 over the rubber. tion has both electrical insulating properties and relatively poor heat conductivity, and is also impervious and substantially resistant to corrosion under conditions normally found in actual practice.

Where the sheath is impervious, it will be seen that should a slit or'perforation Ii occur in the tubing at any point through which the air in the tubing might otherwise escape, the sheath will seal the opening or slit and prevent the escape of air so that operation of the signal will not be materially aflected. Without the sheath on the tubing it will be understood that the air would quickly escape upon an increase in pressure resulting from a fire, so that the signal either would not operate at all or would be so retarded in operation that the fire would gain such headway that the signal when operated would be practically futile.

Another advantage of the sheath is that it protects the tubing against denting and accidental bending. For example, as shown in Figure 10,

uncovered tubing II, when bent for instance to pass around a beam or corner It, may be distorted or even broken as indicated at l9, or under similar conditions, the walls oi the tubing may be crimped together as indicated at 20, both of which conditions would detrimentally affect the operation of the system, if not actually render it inoperative. With the sheath the tube is caused to bend smoothly and evenly as indicated in Figure 12.

Furthermore, the sheath will protect the, tube against becoming torn, bent, dented or kinked when being pulled through a conduit indicated at 2i in Figure 13, or a hole 22 through a wall or the like as shown in Figure 15. During handling Such insulaor shock absorber to prevent or reduce the possibility of denting of the tubing as shown in Figure 14.

The tubing is generally installed by securing it to the wall or ceilingoi a room or space to be protected, by clips 23, and where the tubing is bare, the clips may squeeze the tubing so as to reduce the opening therethrough which would detrimentally aflect operation of the system. The sheath protects the tubing against such squeezing or compression.

In some cases the metal tubing becomes broken as by pulling the same through a hole in the wall, or undue stretching of the tubing. Where the tubing is uncovered, such a break therein renders the system materially defective, if not inoperative, but where the tubing is sheathed as shown in'Flgures l7 and 18, the sheath will bridge the gap between the broken sections to prevent the escape oi air from the tubing and in effect maintain continuity of the passage through the tubing. Where the sheath is somewhat elastic, as when formed of rubber, the two sections of the tubing may even be pulled far apart without materially ailfecting the operation of the system,the sheath stretching as shown in Figure 18 to compensate for the separation 01 the tubing sections.

While we have shown the sheath as completely enclosing the tubing, it should be understood that the sheath may be perforated as shown in Figures 19 and 20 where it is desired' to increase the sensitivity of the tubing to variations in temperature. The perforations 24 may be of any size, spacing and'number suitable for the purpose.

By making the sheath of electrical insulating material, the tubing may be connected in an electrical circuit without danger of short-circuiting of the tubing at any point. This is advantageous in locating a break in the tubing as shown in Figure 5. Here a break is indicated. at 25 at one end of the tubing. A test lamp 2'! may have one terminal grounded and its other terminal connected in a circuit with a battery 28 which is in turn connected to the tubing by pricking through the insulation. The connection of the test lamp with the tubing may be progressively changed along the tubing until a point is reached where the lamp does not light, which will indicate that the break is between the connection of the lamp to the tubing and the point where the tubing is grounded. This greatly simplifies the locating of a break in the tubing over known methods, it having been the general practice to break the tubing at diiierent points, inject air into the tubing at each break until the fluid-pressureresponsive devices failed to operate, and solder each break after the test has been made. In making such a test, the tubing must usually be broken in several places before the break can be located.

The use of electrical insulation on the tubing also makes it possible to constantly electrically supervise the tubing. One method of doing this is shown in Figure 6, where a high-resistance relay magnet 29 is connected in series circuit with the tubing and a source of electricity 30, and cooperates with an armature II which carries a contact to cooperate with a contact 32, the armature and contact 32 being connected in circuit with a signal 33 and another source of electricity 34. When the tubing is intact or unbroken, the magnet 29 is energized to hold the switch 3|, 32

open, but should a break in the tubing occur so as to interrupt the path of the current therethrough, the magnet will be de-energlzed so as to cause the switch 3|, 32 to close and operate the signal 33. Preferably a test lamp 35 is connected in circuit with the source '30 and the source 30 is grounded at 36, the lamp normally not being lighted, whereby short circuits in the tubing may be indicated by'lighting of the lamp. Of course,

short circuits would also be indicated by closing of the switch 3|, 32.

It is also desirable in many instances to prosections 31 and 38, one end of each of which communicates with the adjacent end of the other and is electrically insulated therefrom by a tube of insulating material 39. A switch is connected across the ends of the tubing sections and includes a blade 40 'connected to one sectionwhich cooperates with a contact 4i connected to the other section, the blade being normally held in engagement with the contact 4i by a lever 42 which is manually operable to release the. blade.

A spring 43 normally influences the blade 40 to disengage the latter from the contact 4|, and when the lever 42 is pulled to release the blade 50, the spring 43 will disengage the blade from the contact 4! so as to open the circuit. Such opening of the circuit will cause operation of the signal 33. Therefore the signal 33 will serve as an alarm both upon a break in the tubing and upon manual operation of the switch 40, 4!.

Our invention also contemplates a combination of a fluid-pressure alarm system and a thermostatic electrical alarm system. Such a combination is shown in Figure 21 and, preferably, we utilize a. loop of tubing comprising two sections 44 and 45 which are encased in a common sheath d5 of insulating material. A-thermo-responsive circuit changer, for example a bi-metallic thermostatic switch 41, is connected across the tubing sections with its contacts 58 and 49 normally separated. One end of each section 44 or 45 is in communication with, but electrically insulated from, one end of the other section by an insulating nipple 50. A fluid-pressure-responsive device 5l may be connected tothe tubing sections for operating a signal in the same manner as shown in Figure l. A signal operated by the thermo-responsive circuit changer 41 is connected across the sections 44 and 55 and includes a magnet 52 in circuit witha source of electricity 53 in series with the two tubing sections. The magnet 52 cooperates with an armature switch lever 54 which in turn cooperates with a contact 55, the switch lever being normally held out of engagement with the contact 55 by a spring 56. The switch 54, 55 is connected in series with a signal 51 and a source of electricity 58. Normaly, the switch 54, 55 is open, while the thermoresponsive circuit changing contacts 48 and 49 are separated. Upon an increase in temperature in the vicinity of the circuit changer", the contacts 48 and 49 engage each other so as to energize the magnet 52 and actuate the switch lever 54 to close the circuit through the signal 51.

For electrically supervising the tubing sections 44 and 45, a high resistancejmagnet 59 is connected to the tubing sections at opposite sides of the insulating nipple and cooperates with an armature switch lever which in turn coopconductors.

alsoserve to insulate the tubing from heat asv crates with a contact ii. The switch lever 60 and contact 5! are connected in' circuit with a signal 52 and source of electricity 63. Under normal conditions, the magnet 59 is energized by the current from the source 53 so as to hold the switch 60,- 6| open, but upon a break in the tubing, the circuit is broken so as to tie-energize the magnet 59 to cause closing of the switch 60, BI and operation of the signal 62. H

In some instances it may be desirable to utilize a conductor wire in close relation to the tubing, and we have found that we can accomplish both this result and insulation of the tubing in a very simple and inexpensive manner. As shown in Figure 23, an electrically insulated wire 64 may be snugly wrapped around the tubing 65 with, the convolutions of the helix in close relation.

The wire may serve as a conductor and its insulation both insulates the wire from the tubing and insulates the tubing from contact with other Of course, the wire insulation may well as protect it against corrosion.

While we have shown and described our invention as embodied in several different forms and utilized in certain types of alarm systems, it should be understood that this is primarily for the purpose of illustrating the principles of the invention, and that many modifications and changes may be made in the form of the tubing and in the-manner of its use without departing from the spirit or scope of the invention.

Having thus described our invention, what we claim is:

' l. A fluid pressure actuated signal system comprising a fluid pressure actuated signal device,

a fluid-containing metallic conduit or tubing operatively connected to said signal device, a sheath of heat conducting electrical insulation for said tubing throughout its length, and an electrical signal device connected in a circuit including said tubing for response to a break in the path of current through said tubing.

2. A fluid pressure actuated signal system comprising a fluidpressure actuated signal device, a fluid-containing metallic conduit or tubing operatively connected to said signal device, and a casing of impervious electrical insulating material having relatively poor heat conductivity,

whereby said casing will prevent leakage from arupture of said tubing, the casing being of such a thickness as to prevent operation of the signal by rises in temperature of short duration but to permit operation of the signal by rises in temperature over a prolonged period, and permit the tubing to be electrically supervised.

3. A fluid pressure actuating signal system comprising a fluid pressure actuated signal device, a fluid-containing metallic conduit or tubing operatively connected to said signal device, and a casing of impervious relatively soft and flexible electrical insulating material having relatively poor heat conductivity, whereby said casing will prevent leakage from a rupture of said tubing, the casing being of such a thickness as to prevent operation of the signal by rises in 4. In a flre alarm system comprising a length of electrical and heat conducting rate-of-rise fire detecting tubing, a. signal actuated by fluid pressure generated in said tubing by heating the tubing, a casing of heat conducting and electricity insulating material on said tubing throughout its length of such a thickness as to prevent the generation of sufllcient pressure in the tubing to operate said signal' on sudden rises in temperature of short duration and to permit the gen eration of suflicient pressure in the tubing to operate said signal on rises in temperature of longer duration, said casing also preventing grounding of said tubing on adjacent electrical conductors.

5. In a flre alarm system comprising a length 01' heat conducting rate-of-rlse flre detecting tubing, a signal actuated by fluid pressure generated in said tubing by heating the tubing, portions oi said tubing being normally subject to sudden rises in temperature of short duration, such portions of the tubing being encased in heat insulating material, the casing being of such a thickness as to prevent the generation of sufllcient pressure in the tubing to operate said signal on such'sudden rises in temperature of short duraferent heat conductivity, the casing being of such a thickness as to prevent the generation of sumcient pressure in the tubing to operate said signal on such sudden rises in temperature of short duration in the respective zones and said material permits the generation oi sufllcient pressure in the tubing to operate said signal on rises 01' temperature of longer duration in any of said zones.

7. A fluid pressure actuated signal system comprising a fluid pressure actuated signal device, a fluid-containing metallic conduit or tubing operatively connected to said signal device, and a casing of impervious non-corrodible material having relatively poor heat conductivity, whereby said casing will prevent leakage from a rupture of said tubing, the casing being of such a thickness as to prevent operation of the signal by sudden rises in temperature 01' short duration but permit operation of the signal by rises in temperature oi longer duration, and to protect the tubing against corrosion.

8. In a flre alarm system, the combination of a manually operated watchman's signal and a "rate-of-rise" signal responsive to more than a predetermined rate of temperature rise, comprising a loop of electricity conducting "rate-of-rise fire detecting tubing including two sections connected together in communicating and electrically insulated relation to form a continuous conduit for fluid, said tubing containing a fluid that is expansible in response to a rise in temperature in the vicinity of a portion of the tubing to cause displacement of the fluid within the tubing, a

casing of heat conducting and electricity insulatlng material on said tubing sections throughout their length, a signal means responsive to displacement of the fluid in said tubing, a watchman's manually operable electric circuit changer electrically connecting adjacent ends of said sections, and an electrical signal means connected the length of tubing, a signal means responsive to displacement of fluid within said tubing, a casing of heat conducting and electricity insulating material on said tubing throughout its length, the casing being of such a thickness as to prevent the generation of suflicient pressure in the tubing to operate said signal on sudden rises in temperature of short duration and to permit the generation 01' sufllcient pressure in the tubing to operate said signal on rises in temperature of longer duration, said casing also pre venting grounding of said tubing on adjacent electrical conductors, and an electrical signal device-connected in a circuit including said tubing for response to an impairment in the path of current through said tubing.

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