US1773198A - Safety cut-out for heaters - Google Patents

Description

Aug. y1.9, 1930.

H. l. PIATT SAFETY CUT-OUT FOR HEATERS Fild Nov. 25, 1927 'Patented llig- 19 1930 l i l UNITED 'STATES PATENT;- OFFICE HOWARD I. `I'IA'IT, or LANSING,l IIIcIiIGAN, AssIGNonl 'ro moron' WHEEL conronA- TIoN, or LANSING, MICHIGAN, A conronA'rIoN or MICHIGAN SAFETY GUT-our non IInA'rnns Application med Novemberjzs, 1927. swarm. 235,640. Y

In the operation of heaters, and particularly those operated b a gas-supplied burner, it not infrequentl appens that when the gas supply is turned on, whether manually or automatically, no ame at the burner results by reason of the pilot ame having j gone out. Thereafter, anf attempt to light the burner results in a violent explosion in the gas-filled heating chamber. It is 'the primary object of my present invention to safeguard against such dangers, and to prevent waste of as.

I accomplis this result by providing a dual thermostatic control of a valve or valves in the fuel line, one thermostat subject to the heat provided by the burner itself and another subject to the heat of the pilot; the latter constituting the dominant control.

A further feature of the invention .is the 2 provision against rapid cooling of the heater and heated water by cold air currents after y the burner is' extinguished. This is accom- .l plished by a damper under control of a thermostat subject to the heat of the burner.

While the invention is exemplified in the followin description and accompanying drawing y reference to a water heater supplied with gaseous fuel, it will be understood that the invention is not lso limited in its application.`

In the accompanying drawing,

Fig. 1 is a vertical Section through a heater embodying the invention in its preferred form; and

showlng lamodification.

y' In the drawing, the reference4 11 designates generally a heating chamber communicating `with afflue 12 centrally disposed within a boiler 13 containing a body of water 13. Within the heatin chamber 11 is arranged a burner 14 supplie by the fuel line 15 from a s source notshown.,l

line is mounted a; valve member 17 adapted to seat at 18 and carried by a valve stem 1?. Upon the up er end of the valve stem. 1s threaded a co ar 20, the'location -(if vwhich axially of the valve Stem is controlled througlh 5 the rotation of the valve stem by a suitab e Fig. 2 is a fragmentary sectional detailithin an enlarged portion l16 of the fuel tool engaging within the kerf-21. screw plug 22 g1ves access to the valve for adjustment. Extending laterally from the enlarged valve chamber 16 of the fuel line into the body ,of water within the boiler is a tubu` lar housing 23, the interior of which communicates with the valve chamber and has mounted therein a bimetallic thermostatic bar 24. An arm 25 attached to and forming an extension of the thermostatic bar 24 engages between the two anges of the collar 2O on the valve stem. A

It will be understood that as the thermostatic bar 24 bends under temperature fluctuations of the body of water 13a, the valve will be seated as the temperature rises and unseated as the temperature lowers.

Also extending laterally from the valve chamber 16 and 'in internal communication therewith is a tubular housing 26 having mounted therein a bimetallic thermostatic bar 27, the extension arm 28 of which normally lies above but o ut of contact with a collar 29upon the valve stem. v

A byass fuel line 30 leads from the interior o the housing 26and supplies a pilot ame at 31.

VThe ilot 31;-burns closely adjacent that end of t e housing 26 within which is mounted the thermostatic bar 27 and the heat generated by the ilot iame reserves the ther. mostatic bar 1n such position that thev extreme end of its extension arm 28 is out of contact with the collar 29. However, inthe event the burner 14 and the pilot 31 are both extinguished, the cooling of V'the housing 26 will cause a deection of the thermostatic bar 27 and the end of, its extension arm 28 will bear upon the bar 29 and will force the valve 17 to its seat 18.

From the foregolng, 1t will be evident that comes extinguished for any reason when the burner is not in operation, a lowering of the tive to open the valve 17 b temperature of the water 13 will be ineffecreason of the fact that it is held closed y. the stronger thermostat 27 which is no longer subject to heating by the pilot 31. Thus, in order to supply and ignite fuel at the burner 14, it is first necessary to li ht the pilot. Whereupon as the thermostat becomes heated, the extension bar 28 is displaced from the collar 29 some measure of advantage incident to the invention will be attained by an arrangement of two separate valves within the chamber 16, each acting upon its own seat and. each controlled by one of the thermostats. However,

the action of the two thermostats upon a sin- 'of kthe valve 17 in its close gle valve is advantageous in that the one valve is actuated every time the burner is turned on and off, thus precluding any sticking of the valve which might result if such va ve were only actuated at the infrequent intervals when the thermostat 27 is caused to function by the extinguishing of the 'pilot flame. y

In Fig. 2, a slight modification is shown wherein the thermostat arm 28'l is moved longitudinally into and outof sition above the collar 29 instead of latera l'y as in Fi 1. Such arrangement effects a ositive loc ing position when the pilot is out, so that it cannot be moved by manual force supplementing the thermostat 24.

In order that heat Igny be conserved and rapidcoolin of the eating chamber and boiler by co d air currents may be avoided when the burner is extinguished, a damper 32 is arranged in the heating chamber below the burner to control an vair inlet or rdraft 33. This damper is actuatedby means of a bimetallic thermostatic bar 343 which is subjected to the heat from the burner 13. When the burner is in operation, the damper rmitted to occupy an open position Bil ustrated, but lwhen the burner is extinguished, the cooling of the bar 34 closes the` damper 32 by means of its engagement with the dam r arm 35. The closing ofthe damper prec udes any ,draft of air through the' heat- 1n chamber 11 and the flue 12. Upon the lig ting of the burner, thepresultant heat will cause thdlthermostat 34 to move to the position shown,pennitting the damper to open. Y

I claim: l

1. A safety cut out for heaters comprising the combination wtlia fuel su ply, and a burner and al pilot both suppli thereby, of

a fuel line from the su ply to the burner, a l

2. AI safety cut out for heaters comprising' the combination with a fuel supply, and a burner and a pilot both supplied thereby, of a fuel line from the supp y having connections t'o' both the burnerl and pilot, a valve in the connection to the burner, a thermo` stat continuously connected with the valve and subject to heat generated by the burner,

said thermostat acting upon the valve to close the same at a. maximum temperature and to open the same at a minimum temperature, and a second thermostat subject -to failure to the heat of the pilot and also acting upon the valve in a closing direction at a minimum temperature, the second ther-V mostat -being arranged to overpower the first whereby the valve is held closed if the pilot be extinguished regardless of a lowering of the heat minimum.

3.' A safety cut out for heaters comprising the combination with afuel supply, and a burner and a pilot both supplied thereby, of

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generated by the burner below a Y a fuel line common to the burner and a pilot,

.a single valve in the fuel line to the burner onl a thermostat permanently connected wit the valve and subject to heat generated by the burner, said thermostat acting upon said valve to close the same at a maximum temperature and to open the same at a minimum temperature, and a second thermostat subject to the heat of the pilot and also act-- ing upon the same valve in a closing direction at aminimum temperature, said second thermostat being arranged to overpower the first whereby the valve is held closed to prevent the flow of fuel to the burner if the ilot be extinguished regardless of a lowerj ing of the heat generated by the burner below a minimum.-

4. InA a safety cut-out for heaters, a fuel sup ly, a burner having connection with the fue supply, a valve controlling the supply of fuel to the burner, a pilot burner connected with the fuel supply, a thermostat having a permanent operatingconnection with the valve and arranged tobe influenced by the heat fluctuations caused by the operation of the burner to open and close the f valve, a second thermostat and connection for' closing said valve,'the second thermo ,stat being .inoperative so long as'the pilot burner is ignited but of suicient strength to overpower the rst thermostat to hold the valve closed in case of failure of the pilot burner.

5. In combination with a heater havin a fuel supply and main and pilot burners with separate connections to the supply, a valve in the connection to the main burner, a valveactuating thermostat continuously connected with the valve and responsive to heat fluctuations caused by the main burner to automatically open and close the valve, and a separate valve closing thermostat responsive to the failure of heat from the pilot burner to overpower the first thermostat and close said valveand to hold the valve closed while the pilot is extinguished.

In testimony whereof I have hereunto subscribed my name.

,HOWARD I. PIATT.

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