US1521436A - Automatic draft regulator - Google Patents

Description

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L. DANA AUTOMATI C DRAFT REGULATOR Filed Oct. 18, 1925 Patented Dec. 30, 1924.

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LESLIE DANA, OF ST. LQUIS, MISSOURI.

AUTOMATIC DRAFT BEGULATGR.

Application filed October 18, 1923.

To all whom it may concern:

Be it known that I, LESLIE DANA, a citi- Zen of the United States, and resident of St. Louis, State of Missouri, have invented an Improvement in Automatic Draft Regulators, of which the following description, in connection with the accompanying drawings, is a specification, like characters on the drawings representing like parts.

This invention pertains to automatic draft regulators for stoves, ranges and heating apparatus, more particularly for coal or other solid fuel burning apparatus for rooms, dwellings, and small buildings. The i vention aims to provide a relatively simple and reliable attachment for fuel burning apparatus of existing designs to regulate the draft automatically in response to changes in the temperature of the heater and of the room, both to economize in the consumption of fuel and also to prevent overheating of the apparatus and attendant liability of causing fire.

Other aims and advantages of my invention will appear in the specification.

In the accompanying drawing, wherein l have shown one illustrative embodiment.

of my invention;

Figure l is a side elevation of my improved automatic draft regulator attached to an ordinary domestic heater;

Fig. 2 is a rear elevation of the same looking at it from the right of Fig. 1;

Fig. 3 is a sectional view taken on the line 33 of Fig. 2 and also showing part of the heater in elevation; and

Fig. 4 is a perspective view of one of the thermostatic metal elements.

In the illustrative embodiment of my invention shown in the drawings, my improved draft regulator is attached to the outlet fine of an ordinary room type heater 1 having a nipple 2 to which a collar 3 is secured in the usual manner. The bevel joint between the collar and nipple may be ground to make a as tight lit. The outlet end of the collar receives the usual smoke pipe 4.

A- check draft opening is preferably provided in the rear of the collar and a door 5 is hinged at its lower edge to swing outwardly to open and admit air to the flue.

An operating rod or lever 6 is preferably secured to one slde of the door and has acrank 7 adapted to be engaged and opera Serial No. 669,423.

ated by my in'iproved automatic control mechanism.

In order to operate the draft door automatically in response to changes in temperature of the heater casing and the room atmosphere afiacent the heater, a bending thermostat prc 'erably comprising a plurality of flat, flexible, bimetallic elements 8, each of which may advantageously be made of copper and steel. strips A and B (Fig. 4) which have different coefficients of expansion under changes of temperature, cooper ates with the crank arm 7 so as to permit the door to swing down freely due to its own weight when the t mperature rises and causes the thermostatic elements to bend outwardly or rearwardly.

The thermostat is preferably, though not -ecessarily, enclosed and secured at one end in a housing 9 having perforated side walls 10 one of which is conveniently secured to the collar 3 and also Provides a bearing for one hinge or pivot support of the door 5. The front and rear walls or panels 11 and 12 are preferably perforated, and may be held between ribs or shoulders 18 and lugs or ears let on the side panels (Figs. 2 and by suitable fastening means such, for example, as a bolt 15 passing through the side panels. The front panel 11 preferably has a ledge 16 (Fig. 3) on which the lower end of the thermostat is secured by any suitable means such as a bolt 17 passing through the front and rear walls of the housing and through the bimetallic strips 8 (Fig. The strips may be held firmly seated in a channel on the ledge by a nut 18 threaded on the bolt.

The copper side A (Fig. l) of the thermostat is exposed directly to the heat of the stove through the perforations in the front wall 11 of the housing and contacts with an anti-friction roller 19 on the crank arm T, and, due to the greater coefficient of expansion of the copper than that of the steel, when the temperature rises it will cause the upper end of the thermostat to bend rearwardly away from the crank arm '4" permitting the door to swing downwardly to admit air into the flue and check the draft. Upon a reduction in temperature the thermostat will straighten and swing inwardly toward the stove, operating the crank arm 7 to close the door.

In order to counterbalance the weight of the door 5 when it is in open position, and thereby l ssen the work required to operate the crank '7 and permit the use of a lighter thermostatic element than would otherwise be required, a suitable counterweight 20 (Fig. 3) may be attached to the arm 6. This weight preferably extends substantially vertically downwardly below the arm when the door is in closed position and swings toward the stove through an opening 2i in the adjacent wall of the housing (Fig.

The thermostat is preferablyadjustable sothat it may be set to permit the door to open at a given temperature. I have shown a set screw 2 threaded through the rear wall 12 of the housing and engaging the 'thern'iostat near the lower end:- Iif it is desired to maintain a high temperature, for

example, the set screw may be advanced to force the thermostat against the roller under pressure so that a greater distortion will be required to permit the crank 7 to begin to move. Also the setscrew may be adjusted in the opposite manner to cause the door to open at lower temperatures.

' I While I have illustrated my improved draft regulator as being applied to a reversible collar on an ordinary heater, it will be apparent that it is equally applicable to other types of heaters and to various other parts thereof. 7

' Obviously, my invention is not limited to the details ofconstruction herein described and shown in the drawings, but is susceptible of various changes and modifications.

Having thus described one illustrative em bodiment of my invention and without limiting myself thereto, what I claim and desire to secure by Letters Patent'is:

1. An automatic draft regulator for stoves, furnaces and the like comprising, in combination. a draft door on the outlet flue, said door being vertically disposed and pivoted at its lower edge to swing outwards at the top, a crank arm on saiddoor and a bending thermostat outside said flue 00- operating with said arm to permit said door 'to open and cause it to close upon a rise and tall, respectively, in' the temperature of the stove.

2. An automatic draft regulator for stoves, furnaces and the like comprising, in combination, a draft door on the outlet flue pivoted to swing open under the action of V gravity, said door having a crank arm'thereon provided with anantitriction roller at its ends, and a bending thermostat having its free, end engaging with said roller to hold said door closed normally and to cause 1t 7 to open and close upon a rise and fall, re-

spectively, in the temperature of the stove.

3. In a check draft regulator for stoves. furnaces and, the like, a vertically disposed check draft door hinged at its lower side to swing outwards to open, and a bending thermostat secured beneath said door andcooperating with said door to'hold it in closed position under normal temperature conditions and adapted to permit it to open byfgravity under excessive temperature conditions, said thermostat being adjustable at its lower end whereby to change the'temperature at which it responds sufliciently to permit the door to open. 1

V In a heater, the combination of a collar secured to the outlet flue, a substantially verticalcheck draft door hinged'at its lower side on ,said collar to swing outwards, and heat controlled operating means cooperating with said door comprising a housing supbi-metallic bending V thermostat mounted in said housing and having its side of greater expansibility arranged adjacent said collar and exposed directly to heat radiating from the flue, whereby an increase in temperature of said flue causes said. thermostat element to bend away from said flue and cause said door to swingopen.

6. An automatic lcheck draft regulator orted on said collar outside said flue a p i element comprising, in combination, a vertically disposed door hinged at its lower side and tending to sw ng open by gravity, means for holding said door in closed position under normal temperature conditions and permit ting it to open under predetermined temperature conditions, and a counterwelght for said door disposed below. its hinge pivot axis and adapted to aid said means in returning it to closed position atter it has opened and the temperature falls below said predetermined amount.

7. An automatic draft regulator for stoves, furnaces and the like, comprising, in combination, a collar secured'to the outlet flue having a draft opening in an exposed wall, a draft door adapted to close said opening and having one edge mounted in a pivot bearing on the wall of said collar, a perforated housing providing a second bearing for said door and secured to the collar at one side of said opening, and aflexible thermostat secured at one end in said housing and with its free'end cooperating with said door to cause it to open and close under the influence of temperature conditions adjacent the heater.

' 8. An automatic draft regulator comprising, in combination, the collar 3 supporting with said crank arm to cause the door to open and close under the influence o't changes 1n surrounding temperature conditions, all sub- 10 stentielly as shown and deseribed.

In testimony whereof, I have signed my name to this specification.

LESLIE DANA.

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