US1734210A - Draft control for steam-boiler furnaces - Google Patents

Description

Nov. 5, 1929. 1. A. JOHNSON. Er A1.

DRAFT CONTROL FOR STEAM .YBOILER FURNACES Filed March ,5. A1928 2-,Sheets-Sheet l ooooo I IIIILIIU Illlllb Y, ln/vanto@ :JJUZ 716 071 Rhume/14 Nov. 5, 1929. J. A. JOHNSON ET AL Y A DRAFT CONTROL FOR STEAM BOILER FURNACES 2 Sheets-Sheet 2 Filed March 5. 1928 Patented Nov. 5, 1929 ure-aire vairs JAMES A. lJOHIN'SO1\T AND GEORGE A. BENSON, OF VIRGIQNIA BEACH, VIlIRGIN'IA,` AS- SIGNORS TO DRAFT-RATER CORPORATION, OF NORFOLK, VIRGINIA, 'A' CORPORA- TION OF VIRGINA DRAFT CONTROL "FOR STEAIVI-BOILERFURNACES Application filed March 3,

rIhis invention relates to draft controlling means for steam boiler furnaces or like mechanisms, and the general obj ect of the invention is to provide means for reducing the draft either upon a sudden increase in the draft as, for instance, when fresh coal is thrown upon the fire, or the reducing of the draft when an excess of steam is being genera-ted, or in other words when the pressure of the steam has risen above a predetermined point.

A further object is to provide for this purpose a draft damper or valve operating inA connection with a stack, and provide readily adjustable means whereby the damper may be held in a normal position at a predetermined distance from the lower end of the stack, the damper being adjustable to increase or decrease this distance7 and further in this connection to provide means tending to resist the initial movement of the damper toward the stack or toward the seat but permitting a sudden closing of the damper.

Still another object is to yprovide means whereby the damper, as before remarked, will be shifted toward its seat to reduce or check the draft through the stack when steam has been raised beyond a certain pressure, which includes al relief valve, a cylinder into which the relief valve exhausts, the cylinder having a piston operating upon the damper to shift it toward the stack when the piston is subj ected to the pressure of the steam, thus rendering the action of the damper automatic where the steam is being produced in excess of requirements.

Other objects will appear in the course of the following description.

Our invention is illustrated in the accompanying drawings, wherein Figure 1 is a front elevation of the smoke box of a steam boiler with the lfront wall thereof removed, showing our draft regulator applied to the interior thereof; Y

Figure 2 is a vertical sectional 'view on the .line 2 2 of Figure 1; I

Figure 3 is a fragmentary sectional view showing the draft regulator applied to a modified form of flue; I

Figure et is a fragmentary sectional view 1928. Serial No. 258,976.

showing another application of the draft regulator.

Referring to these drawings, 10 designates the smoke box of a water heater or boiler and 11 Vdesignates the lire tubesl extending 'through the boiler 12 and entering the smoke box, the smoke box beingprovided with the usual stack 13 extending therefrom. It will be understood that the furnace may be of any suitable or usual type and that the embodiment which we have illustrated is purely illustrative of one application of our invention.

Disposed within the smoke box isa cylinder 14thaving therein a float 15. VThis float carries a stenil extending upward through a guide 17 of any suitable character. At itsA upper end this stem' carries upon it the bellshaped damper 18 which is larger` than the opening into the lstack 7through the top of the smoke box. This damperl will never, even at its=highest point,seat' against the 'lower end of the stackY so as to completely` cut off the draft but` the dampenmay be shifted into a position of approximate contact with the lower end of the stack or with a seat inside the stack, as desired, and under these circumstances will cut down orrreduce the draft materially. rEhe damper is retained in a normal position spaced from the lower end of the stack or from its seat by the weight of the damper, the stem or rod 16 and the weight of the float 15. l This float is normally supported by a body of water or other liquid disposed within the cylinder 14 which is maintained at any desired height by means now to be described. From theA cylinder 14 there extends a pipe 19 which opens into a cylindrical container 20.

Enteringr into the container is a discharge pipe 21 which is vertically shiftable through a guidebracket 22 and is held in a shifted position by a set screw 23 or equivalent device.- The upper end ofthis pipe 21 is'cony nected by a flexible pipe 24 to the lower end of a tank 25, this tank 25 being a closed tank and having therein a certain amount of water. It will be obvious novi7 that thelevel of water Within "the container and, therefore,Y the level of within the cylinder llt will depend sor upon the adjustment of the pipe 21 and that Athe container will be filled up to a point raising or lowering the pipe 21, the height of Y stem extending upward 'through the top of theV water vwithin the float chamber 14.1nay be regulated and this, of course, will regulate .m the height ofthe float 15 and thev distance of the valve or damper 18 from its seat.

Under these circumstances, ifa sudden draft is caused upward through the stack,

such a draft, for instance, as is caused by thev opening of the furnace door and the throwing of fresh coal in upon-the lire which causes what may be termed a smoke explosion, `the force of the draft rushing out through the smoke stack will cause the damper tomove toward the stack, thus reducingthe draft and preventing the escape up the stack of the hot air and other heated products of combustion and the consequent loss of heating power. A mere slow increase of draft, however, will not cause this' upward movement of the damper as the damperis lheld down by the weight of the damper rod and the float. Y

While the float is supported within the water,- the lower portion of :the float has no Weight but as soon as the float is free from the water it has'an additional weight tending to check the upward movement ofthe damper. As soon' as the draft has been ref duced below a certain point, of course, the

damper will fall to its initial position which isA governed by the adjustment of the pipe 21, as heretofore stated. v

In order to provide for an automatic movement o-f the damper toward its closed position when anV excess of steam is being generated, we' mount upon the damper rod the cross bar 26 or an equivalent element and mount upon the'side of the cylinder 14 bev neath this cross bar a cylinder 27 wit-hin which a piston" 28 operates, this piston having ay the cylinder and bearing against the under face of the cross bar 26. The lower end `of the cylinder 27A is connected by means of a pipe 29r to thecasing 80 of a relief valve of any usual or suitable type, this-relief valve being so set by the usual mechanism for this purpose that .it willv pop ofi' or relieve the pressure when the pressure is about five.

pounds below the predetermined pressure re.- quired to operate the usual pop-off valve. This casing 30 is connected by a pipe 31 to thev steam drum of the engine or to any other suitable chamber having therein steam generated by the boiler. 'It will, therefore, be obvious that if an excess of steam is created and the pressure `increases beyond a predetermined `point that theA relief valve will act, permitting ytheV steam to pass from the'pipe Thus it will be seen that we have provided Y an automatic draft regulator and an automatic steam regulator'or pressure regulator which will act to impede or reduce draft passing through the stove either upon a sudden increasel of draftorvupon an increase in the steam pressurebeyond a predetermined amount to which the relief valve is set.

In Figure 3, we have illustrated a constructiony operating on exactly the same principle as heretofore described, except in this case the stack 18A isshown as angular in formwith the iioat chamber 14 disposed below the bend of the stack and in axial alignment with the axis of the stack, and in this case the float chamber is disposed not within al smoke box but below the stack. Otherwise than this it operates in exactly the same manner as the construction first described. i,

In Figure 4, we illustrate another variation of our construction wherein a header. 3 is provided into which two stacks 13 open, these stacks lleading from separatefurnaces and from which a stack 1311V extends. The damper l18 is disposed beneath the lower end of the stack 13b and the stem of this damperY is mounted upon a lever 32, the outer end of y which carries the vertical stem or rod 34 which extends downward and connects to the iioat disposed within theV float chamber 14. It will be seen that this is also a mere variation in the'arrangement of parts and does y not .depart from the invention.

While'we have illustrated certain details of construction and arrangement of parts, it is to be understood thatthis is purely illustrative of the several embodiments shown and to illustrate the general features of the invention and how it may be' applied and that we are notv to be limited to these details except as defined in theappended claims.

We claim :-v v

1. In a furnace having a smoke box and a smoke flue extending therefrom, a damper mounted within the smoke box and below the lower end of the flue and adapted to move toward or from the flue, the damper being movable toward the flue under the suction created by an increased draft through the flue, a vertically disposed rod upon which the damper is mounted, means acting to limit the downward movement of the rod and damper, said means comprising a oat mounted upon the rod, a liquid chamber in which said Heat is disposed, and manually operable means for increasing or decreasing the amount of liquid Y i of an increase of draft through the Hue to reduce the effective area of the Hue passage, said damper being urged away from this last named position, a liquid chamber, a Hoat therein operatively connected to and movable with the damper, a barometric tank, a liquid container disposed on a level with the liquid chamber and communicatively connected thereto at its lower end, and a pipe entering said container and operatively connected to the tank to take liquid therefrom, the pipe being vertically adjustable to thereby control the level of liquid in the container and in said chamber.

3. In a furnace having a smoke Hue, a

damper movable under the influence of eXcessive draft to reduce the effective area of the Hue, a liquid chamber, a Hoat therein operatively connected to and movable by and with the damper, the float being normally supported by the liquid and supporting the damper.

4. In a furnace having a smoke flue, a damper movable under the inHuence of eX- cessive draft to reduce the effective area of the Hue, a liquid chamber, a float therein operatively connected to and movable by and j with the damper, the float being normally supported by the liquid and supporting the damper, and adjustable means for controlling the height of liquid in the chamber.

5. In a furnace having a smoke Hue, a damper movable under the inHuence of eX- cessive draft to restrict the Hue opening, a receptacle containing liquid, a member therein and connections between the member and the damper whereby as the damper moves to restrict the opening of the Hue, the member is withdrawn from the liquid and applies its weight as a bias returning the damper to its normal position.

6. In a furnace having a smoke Hue, a damper movable under the inHuence of excessive draft to restrict the flue opening, a receptacle containing liquid, a member therein and connections between the member and the damper whereby as the damper moves to restrict the opening of the Hue, the member is withdrawn from the liquid and applies its weight as a bias returning the damper to its normal position, and adjustable means for controlling the liquid level in the receptacle.

7. In a furnace having a smoke Hue, a damper movable under the inHuence of excessive draft to restrict the flue opening, a receptacle containing liquid, a member therein and connections between the member and the damper whereby as the damper moves to restrict the opening of the Hue, the member is withdrawn from the liquid and applies its Weight as a bias returning the damper to its normal position, a barometric tank, a liquid container disposed on a level with the liquid receptacle and connected therewith, a pipe

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