Closely allied to the automatic sprinkler proper, is the system of sprinkling by perforated pipes through an auto-matic valve. This system, first made practical by Leonard, has lately come to the front under the name of the " Victor " system. As shown in Fig. 46, 47, the valve is held up, as in Harrison's plan, by a soldering at the lower end of the stalk, and this soldering is surrounded by a collecting eons of metal. On the fall of the valve, the water rashes into the long pipes, and is distributed in jets through its perforations. One valve suffices for 400-500 sq. ft. of surface protected.
There are several useful adjuncts employed in connection with these appliances. Grinnell fixes in bis main pipe, between the supply-tank and the sprinklers, a valve arranged to be moved by the water whenever, on the opening of any 6prinkler, the pressure is relieved. This valve then sets a lond gong in motion, and sounds an alarm. Electric alarms are also used in connection with,
Fire-doors may be made automatic. The Boston Company have investigated this question by their experts, and have pronounced most emphatically against iron fire-doord. They say they curl up and keep out the water and men, and allow the fire to spread. They announce the opinion that a well-built wooden door, protected by tin plate on each side, is much better: the wood will not burn, but it beomes charred, holds the tin together, and keeps out fire better than an iron door would. They make it automatic in the following way: - The door is arranged to slide shut on an inclined track, and is kept open by a rod, which is made with a scarf-joint in two parts, united in the centre, inside a copper ferrule or sleeve which nicely fits the two ends of the rod. The joint is shown in Fig. 48. This sleeve is made in longitudinal halves, which are secured together with fusible solder. The ends of the rod where they come together are cut at an angle of 45°, and therefore tend to force the sleeve open when the solder melts.
One end of the rod is fastened to the door, and the other end to the door-frame. Another device for holding a fire-door open is the fusible link.
Victor valve, closed.
Victor valve, open.
The oval link (Fig.~49) used in the Walworth sprinkler is unsuited to stand a tensile stress. The Grinnel link (Fig. 50) is well suited for this purpose; it consists of two links stamped in thin brass, laid over one another so as to overlap throughout 3/5 of their lengths; they are soldered together, and the central portion is filled up with a bit of copper wire and with solder. These links are introduced into some convenient part of a cord which holds up a weight, the falling of which releases the fire-door.
Edward Bright's arrangements for fire alarms are excellent things. There are several more recent: a very good fire alarm, by Martin; another, known as Rowley's; and Grinnell has applied an electric alarm in the form of a fusible link. He introduces somewhere into the electric circuit a little link, which may be made of a thin strip of alloy, in some place near the ceiling; on melting, it breaks the circuit and rings an electric bell, if it is arranged to work in a closed circuit, and there you have a fire signal of the first order. This is used in England. There is another open circuit system used in connection with small Grinnell installations; it is arranged so that when the heat reaches a catgut band strained inside a copper tube it contracts, and makes contact between two strips of metal which go to an electric bell.
Lorrain's is based upon a system for making an electric contact. It is a little thermostat arrangement, with a strip of two metals soldered together, which, when they are hot, bend and touch a contact screw, making the electric circuit complete. Further, there is an arrangement of an electromagnetic solenoid; it is a coil of wire with an iron core, which is attracted in when the circuit is completed. When that core is attracted in, it bears on a valve, which is intended to perform the following function: - There is a tank containing sulphuric acid, of course constructed of some acid-proof sub-stance, such as stoneware. The valve allows a little acid to trickle into a lower chamber, where there is already a solution of carbonate of soda, and this generates an enormous amount of carbonic acid, which flies up through pipes, and so, with or without water, will immediately cause a great distribution of spray of carbonic acid (which itself is a splendid extinguisher of fire) all over that part of the factory. There is also a centrifugal arrangement for distributing the water, which is turned on, and is caused to rotate by a small electro-magnet, which is also automatic.
And an independent piece of apparatus, quite distiuct from the others, is a very strong cylinder charged with compressed carbonic acid, having a valve weighted, but propped up by a little trigger arrangement below. Directly the electric circuit is completed by the arrangement first described, the electro-magnet below the cylinder attracts its armature, lets off the trigger, the weight falls, turns on the valve, and you immediately have carbonic acid either distributed through pipes or led directly into the open air.
Scarf-jointed rod united by sleeve.
One of Jolin's devices to take the place of the Grinnell link is a little button, in which the edges of the brass discs receive the thrust, and take off the stress from the alloy. When it is required for use in a cord to hold up a valve lever or a fire-door, it is provided with a couple of loops to attach it to the cord. It is readily replaceable after the fire has burned out, and would be a little more reliable, perhaps, than the Grinnell link. Another contrivance of Jolin's is an arrangement to make a grenade automatic. The greatest objection to grenades is that they do not throw themselves, and they do not easily break. Jolin wants to make these grenades self-acting when a fire breaks out, therefore he proposes to hang a grenade up in a sort of cage at the top of the room, the cage being provided with a small button held together with fusible alloy. When that is affected by the ascending hot air, the button bursts open, the cage opens and allows the grenade to fall, and directly the grenade falls, an iron weight follows after it, and breaks it in mid-air and sprinkles the liquid about.
The use of ammonia for this purpose was proposed by a committee of the Polytechnic Society at Munich (see ii. 293). A much cheaper and more easily accessible extinguisher is ordinary ammoniacal gas-liquor of 5°-6° Tw. This was tried with the greatest success to extinguish a fire of a most formidable kind which suddenly broke out in a tar distillery. The heat of the fire causes a large disengagement of carbon dioxide and sulphuretted hydrogen, besides ammoniacal gas and steam. The use of gas-liquor (to be well settled and stored in closed boilers, with suitable piping and forcing power, etc.) has been strongly recommended for extinguishing fires in cotton mills. (Jl. Soc. Chem. Ind.)
(13) Proto-chloride of manganese, 33 per cent.; phosphoric acid, 20 per cent.; boric acid or borax, 10 per cent; chloride of magnesium 12 per cent.; chloride of ammonium or sulphate of magnesia 25 per cent. The materials are immersed for 6-8 hours in this solution at the temperature of ebullition. They quickly become impregnated with double salts, insoluble in water, and the incrustations that are formed effectually protect the materials treated against fire. When exposed to a quick fire, they carbonise, but produce no flame. (Prof. Winckel-man.)