US2752587A - Gas escape alarm - Google Patents

Description

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United States Patent O GAS ESCAPE ALARM Mac Naphtal and Irving Naphtal, Los Angeles, Calif.

Application November 16, 1953, Serial No. 392,232

2 Claims. (Cl. 340-237) This invention relates to systems used for the detection of the presence of gases such as illuminating gas, carbon monoxide gas and the like. A more particular object of the invention is to provide a safety device that automatically gives an alarm when the air in the space occupied by the device becomes dangerously poisoned because of having a noxious gas injected thereinto, and continues to ring until it is manually shut off. j

Illuminating gas is used to a large extent in buildings and homes for cooking and heating, and it is one object of this invention to avoid dangerous situations caused by the leakage of gas from damaged or broken pipes or joints caused by settling of the structure or by hard usage. Gas heaters and gas appliances in closed rooms have caused many deaths due to the gas being momentarily cut oft by trouble in the system; by accidental opening of the valve, or by a gust of air blowing out the ame.

Although the idea of providing an alarm giving device which is automatically operated when the air becomes dangerously laden with gas is not broadly new, there remains much room for improving such alarms so that they may be made in a practical and economical manner, and may be operated with a minimum maintenance expense and a maximum operating etliciency, which is a further object of the invention.

Another object is to provide a device that detects the presence of noxious gases and gives an audible alarm, which is provided with a main casing containing the long lasting elements of the device and a detachable, auxiliary casing containing parts that should be changed periodically.

Other objects and advantages of the invention will become apparent from the foregoing specification, and the drawing forming a part thereof, in which:

Fig. l is -a partial plan view, with parts removed, and parts in section of my improved gas escape alarm.

Fig. 2 is a sectional view on line 2 2 of Figs. 1 and 3.

Fig. 3 is a sectional view on line 3 3 of Fig. l.

Fig. 4 is a bottom plan view of the casing forming the major part of the improved device.

Fig. 5 is a wiring diagram of the device.

In the drawings, the numeral designates a casing to enclose the major part of the device, including a top wall11, and depending side walls 12 and 14. Spaced from the top wall 11, and coextensive therewith is a bottom wall 15 having upstanding side walls 17 and 18, held in alignment by lugs 19, of the top wall 11, to provide the remaining walls to complete the box like casing 10. Upstanding from the bottom wall 15 and extending parallel to the walls 12 and 14 are the flanges 20, having central apertures 21 therein to register with drilled and tapped apertures 22 in the walls 12 and 14 for fastening the top, bottom and side walls into a complete unit, by means of screws 23.

The top wall 11 has depending therefrom, and fastened thereto (see Fig. 4), a transformer 25, a buzzer 26 and a relay 27, and extending upwardly through the openings 28 and 29, in the top wall 11, are a switch 30 and a re- ICC ceptacle block 31 of insulating material adapted to co-act with the terminal block 32 also of insulating material. The block 32 has slots similarly spaced to slots 31' in the block 31, thus insuring that the terminal block and parts associated therewith will face in the desired direction at all times, when coupled together. The block 31 also has a plurality of depending contacts 31" to connect it to the parts in the casing.

The terminal block 32, extends through an opening 33 in the bottom wall of the auxiliary casing 33a which registers with the opening 28 in the wall 11. Extending upwardly from the bottom wall, are side walls 34 and 35, and extending between the same are flanges 36 and 37 adapted to be fastened to the depending co-extensive perforated walls 38 and 39, by screws 40, of the perforated cover 41.

The side walls 34 and 35 are joined, adjacent to one end, by -a strip of insulating material 42, fixed to the walls by screws 42'-, and centrally bored at 43 to receive the plug 44. The said plug is slotted to receive the bimetal element 45, which is held in place by a set screw 46. At its free end, the bimetal element 45 has a contact 47 which aligns with an adjustable spring charged contact 48, carried by the side wall 35. The strip 42, between the Walls 34 and 35 and the element 45, is bored to receive the refractory rods 50, preferably made of ceramic material, which are held in place by set screws 51.

The terminal block 32, above the wall 11, is provided with a plurality of contacts, one of which is connected as at 52 with one end of a platinum high resistance wire 53, which is wound around and across the rods 50 to form a catalyst resistor unit 53a. The free end of the wire 53 is connected to contact 54 of the block 32. A wire 55 of the block 32 is also connected to the contact 54 and thence to the element 45.

The area 56 (see Fig. 2) between the rods 50 and the platinum wires 53 completely surrounds the portion of the element 45 that passes through the area 56 due to the radiation of heat by the catalyst resistor, thus providing a good heat conductive relationship. The perforations 40 in the cover 41 insure that the noxious gases will permeate therethrough to reach the area 56.

As shown in Fig. 5, the primary side of the transformer 25 receives at 25a a voltage of 115 volts which is stepped down at the secondary side to six volts, at 25b. The cur rent normally ilows from 25b through the wire 57 and switch 30, and thence through the points 58 and 59 to the catalyst resistor 53a, and thence through the wire 65 back to the transformer.

When a combustible gas of a predetermined concentration passes through the perforated cover plate 40 it comes into contact with the heated platinum catalyst resistor 53a, and combustion takes place, thereby causing a heat rise in said catalyst resistor 53a, which was previously normally heated but not suiciently to bend the bimetal element 45. The bimetal element 45 which is located in the center of the area 56, at this time becomes superheated which bends the bimetal element sufficiently so that it contacts the point 60, closing the power circuit through relay winding 68.

At the time the relay 27 is energized it causes the points 58 and 59 to open and deenergizes heating element 53a. At the same time the relay points 61 and 62 close and lock up the relay as well as energize the buzzer 26 connected in shunt to the relay coil.

The current, with the alarm in operation, now ilows from 25b of the transformer, through the wire 57, switch 30 and wire 63, and thence into the buzzer 26, causing it to operate and provides the desired automatic gas escape alarm; thus, the current completes the circuit through the points 61 and 62, and thence back to the transformer 25,

the bimetal switch meanwhile has cooled due to the element being open through the points 58 and 59.

rThe switch 30 by use to momentarily open the relay winding circuit can manually revert the alarm device to its original condition for an alarm circuit should gas again escape, and ow into said area 56.

The catalyst wire 53a is the most vulnerable element in the system, followed closely by the bimetal strip 4S and these are both encased in the perforated secondary housing 33a which is connected to the main casing, containing the more stable components of the circuit, by a simple plug and socket connection providing mechanical and electrical connections between casing and secondary housing. Thus the vulnerable parts may be easily repaired or replaced in a unit.

From the foregoing it is apparent that we vhave invented a new and improved gas detector and alarm, that is practical, elicient, and safe in operation with maintenance costs held to a minimum.

The embodiment of the invention shown herein is merely illustrative, and not restrictive. Numerous changes in the size, shape and arrangement of the parts may be made Without departing from the spirit of the invention, or the scope of the appended claims.

We claim:

l. In a gas escape alarm, in combination, an electric power source; a relay havin a coil, a set of normally closed and a set of normally open contacts; a normally open switch in circuit with said source and said coil; a signal connected in shunt'to said coil; a bimetal strip arranged when heated to close said switch; a resistance wire adapted to cause catalytic burning of the gas to be detected connected to said source through said normally closed contacts and being arranged to radiate heat directly to said bimetal strip; and said normally open contacts being connected to close a holding circuit from said source to said coil when the latter is energized.

2. The alarm as defined in claim 1 having a normally closed switch in said holding circuit for momentary opening to reset the alarm.

References Cited in the tile of this patent UNITED STATES PATENTS 1,088,611 Neubauer 'Feb. '24, `1914 2,029,402 Alexander Feb. 4, 1936 2,107,525 Derby Feb. 8, 1938 2,345,772 Robertson et al Apr. 4, 1944 2,400,940 McCollum May 28, 1946 2,533,339 Willenb'org Dec. l2, 1950 2,535,950 Page Dec. 26, 1950 2,621,240 Kemper Dec. 9, 1952

Claims (1)

1. IN A GAS ESCAPE ALARM, IN COMBINATION, AN ELECTRIC POWER SOURCE; A RELAY HAVING A COIL, A SET OF NORMALLY CLOSED AND A SET OF NORMALLY OPEN CONTACTS; A NORMALLY OPEN SWITCH IN CIRCUIT WITH SAID SOURCE AND SAID COIL; A SIGNAL CONNECTED IN SHUNT TO SAID COIL; A BIMETAL STRIP ARRANGED WHEN HEATED TO CLOSE SAID SWITCH; A RESISTANCE WIRE ADAPTED TO CAUSE CATALYTIC BURNING OF THE GAS TO BE DETECTED CONNECTED TO SAID SOURCE THROUGH SAID NORMALLY CLOSED CONTACTS AND BEING ARRANGED TO RADIATE HEAT DIRECTLY TO SAID BIMETAL STRIP; AND SAID NORMALLY OPEN CONTACTS BEING CONNECTED TO CLOSE A HOLDING CIRCUIT FROM SAID SOURCE TO SAID COIL WHEN THE LATTER IS ENERGIZED.

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