US2807013A - Flue failure detectors - Google Patents

Description

INVENTORJ filiorn y J L PROUGH ET AL FLUE FAILURE DETECTORS Flled May 12 1955 Sept. 17, 1957 .I knit 589w Eu r 2,807,013 Patented Sept. 17, 1957 FLUE FAILURE DETECTORS James L. Prough and Thomas D. Havlin, Altoona, Pa.

Application May 12, 1955, Serial No. 507,758

4 Claims. (Cl. 340-243) This invention relates to means for detecting flue fail ures and particularly to a device for use in conjunction with automatically fired furnaces to indicate stoppage or failure of the flue or chimney which might lead to the discharge of carbon monoxide or similar noxious gases into the building containing the furnace.

The failure or stoppage of a flue or chimney in connection with automatically fired furnaces has led to the loss of life by reason of the discharge of carbon monoxide into the building in the flue gases. This problem has been recognized for some time and various elforts have been made to solve it. Numerous devices have been proposed which depend upon the use of catalytic agents to combine with the noxious gases to actuate an alarm system or otherwise warn of the failure. No simple, non chemical device for detecting the escape of flue gases has, however, been proposed.

The present invention provides a simple, inexpensive, purely mechanical device for indicating the failure or stoppage of a flue and the discharge of flue gases. The device of this invention does not depend upon chemical reactions and expensive catalysts.

It is accordingly the principal object of the present invention to provide a simple, inexpensive mechanical means for detecting flue failure.

It is another object of this invention to provide a means for detecting flue failures which do not depend for effectiveness upon chemical reactions or the presence of chemical catalysts.

It is a further object of this invention to provide a structure for detecting flue failures comprising in combination with a flue diverter having an opening to the atmosphere, a low temperature fusable link, means for passing an electrical current through said link and alarm means actuated by fusion of said link.

It is another object of this invention to provide a variable fusable link whose resistance to fusion may be varied.

It is another object of this invention to provide a method of making a low temperature fusable link by compressing a portion of molten low temperature fusable material between flat polished surfaces.

Other objects, advantages and purposes of this invention will be apparent from a consideration of the following description and the accompanying drawings in which:

Figure 1 is an isometric View of a furnace fitted with the flue detector of this invention.

Figure 2 is a top plan view of one form of this invention partly cut away.

Figure 3 is a section on the line IilI-II'I of Figure 2.

Figure 4 is a partial top plan view of a second embodiment of this invention.

Figures 5 and 6 are sections through polished plates showing the method of making a fusable link according to this invention.

Figure 7 is a schematic wiring diagram of an alarm circuit according to this invention.

Figure 8 is a longitudinal section through a variable form of fusable link according to this invention.

Figure 9 is an end view of the link of Figure 8 view from the right.

Referring to the drawings there is illustrated an automatically fired gas furnace 10 of conventional design provided with a diverter bell 11, a flue pipe 12 and chimney 13. The diverter bell 11 is open at the bottom 14 in the usual manner. All of the foregoing is old and well known.

A housing 15 is fixed in the opening 14 of the diverter by means of a semi-flexible sheath 16 and a bracket 17. Openings 18 are provided in the bottom of the housing 15. A cover 19 is fitted on the housing 15 and is provided with an opening 20 and shield 21 to prevent the entry of dirt into the housing. A resilient blade conductor member 22 is fixed to an insulator member 23 which is in turn fixed in the interior of the housing. The conductor member 22 is arranged so as to tend to move into a position intermediate the cover and the housing, but the free end 22a is held in contact with the housing by a spot of low temperature fusable metal 24. A pair of conductor members 25 and 26 are brought into the housing 15 through the sheath 16. One of said conductors 25 is connected to the resilient blade conductor 22 and the other 26 is connected to the housing 15, making a complete circuit through conductor 25, blade 22, fusable metal 24, housing 15 and conductor 26. Conductors 25 and 26 are connected into an alarm circuit such as that shown in Figure 7.

In Figure 7, a transformer 27 is connected to a source of electrical current 28. One of the leads 25 is connected to one side of the transformer output 29. The other lead 26 is connected to the energizing coil of a normally closed relay 30 and through the coil to the other side of the transformer output. A buzzer or bell 31 is connected to the transformer 27 in a parallel circuit with leads 25 and 26. The normally closed relay 30 is placed in the buzzer circuit.

The apparatus of the invention operates as follows: If there is a failure in the flue made up of pipe 12 and chimney 13, the hot flue gases will be diverted through opening 14. The hot gases passing through opening 14 will enter through openings 18 and 20 into the interior of housing 15 and will melt the fusable metal 24. This will release the blade 22 and break the circuit through leads 25, housing 15, blade 22, lead 26 and the coil of relay 30. When the coil of relay 30 is deenergized, the relay will close to its normal position completing the circuit through buzzer 31. The buzzer 31 will ring until the circuit is again broken.

A warning button 32 is preferably fixed on the blade 22 to pass through an opening 33 in the cover 19 of housing 15. The button 32 is insulated at '24 from the blade and is preferably colored red to serve as a visible warning of the release of the blade 22 in the event that the buzzer 31 should fail to give its audible warning.

In an alternative construction as shown in Figure 4, a strip of fusable metal 35 may be placed within a cylinder of screen wire 36 or similar material through which the hot gases may pass to reach the strip 35. The strip 35 is fixed to end caps 37 conducting material which are held in spring clips 38 mounted in housing 39 corresponding to housing 15 of Figures 2 and 3. Leads 40 and 41 are attached to the clip 39 and correspond to leads 25 and 26 of the embodiment of Figures 2 and 3 and are substituted for those leads in making up a circuit similar to that of Figure 7.

The operation of this embodiment is similar to that of Figures 2 and 3. Hot gases entering the housing 39, pass through screen 36 to strip 35 which melts and breaks the circuit through leads 40 and 41.

In Figures 8 and 9 there is illustrated a variable type of fusable link usable in this invention. A plurality of wires 42 (three in this case) are connected at one end to a cap 43 fixed to a cylinder housing 44 through insulators 45. The other ends of the wires 42 are fixed to an end cap 46 which is insulated from housing 44'and rotatable. relatively thereto. Rotation of the cap 46 causes the. wires 42 to be twisted together, thereby varyin: their resistance to fusion. Preferably the cap 46 is ll him With'the various possible temperature combinations at which the wires, 42 can be made to fuse.

In Figures 5 and 6 there is illustrated a method of billing low temperature fusable links suitable for use in this invention. Conventional materials are of such m that they do not melt suificiently rapidly for best resukein this invention. Accordingly a method of mak- 8 eulibfaetory material has been developed. A small amunt of molten low temperature .fusable material 50 is placed on a polished plate 51 and a second polished M53 iaihwght. down on the molten material 50 under me. The molten material 50 is then spread out in athiufilm 53 between the two plates 51 and .52. This film: 53 is then cut into strips .of required width and thinness.

preferred forms. of the invention have be n illustrated and described above it will be understand that this invention may be otherwise embodied ithin-the scope of the following claims.

We claim: l. A flue failure detector comprising in combination a line diverter having an opening to the atmosphere, a housing adjacent said opening, a low temperature fusible link in said housing, at least one access opening in the housing facing the opening in the diverter whereby gases leaving the diverter come in contact with the fusible link, means for passing an electrical current through said link in series with a normally closed relay held in the open position by current flow through the link and alarm means actuated by closing of the normally closed relay.

2. A flue detector as claimed in claim 1 wherein the position of the housing facing the opening in the diverter is covered with screen wire acting as a plurality of access openings.

3. A flue failure detector as claimed in claim 1 wherein the fusable link is made up of a plurality of spaced wires of low temperature fusable material and means for twisting said wires together intermediate their ends whereby their resistance to fusion is altered.

4. A fusable link comprising a housing, a plurality of spaced wires. of low temperature fusable material extending from two opposite ends of the housing, and means for twisting said wires together intermediate their ends whereby their resistance to fusion is selectively altered.

References Cited in the file of this patent UNITED STATES PATENTS 2,184,983 Tornquist Dec. 26, 1939 2,420,481 Jackson-6t a1. May 13, 1947 2,496,687 Amprim Feb. 7, 1950 2,682,299 Field June 29, 1954 FOREIGN PATENTS,

110,033 Australia Mar. 6, 1940

Images