US3236228A - Smoke pipe and damper therefor - Google Patents

Description

Feb. 22, 1966 w. HODGINS SMOKE PIPE AND DAMPER THEREFOR Filed March 20, 1963 FlG. I.

FIG. 3

FIG. 2

INVENTOR WILLIAM H zDGINS ATTORNEY United States Patent 3,236,228 SMOKE PIPE AND DAMPER THEREFOR William Hodgins, Ottawa, Ontario, Canada, assignor to Hodgins Combustion Devices Limited, Ottawa, Ontario, Canada, a company incorporated of Canada Filed Mar. 20, 1963, Ser. No. 266,600 2 Claims. (Cl. 126-293) The present invention relates to improvements in a smoke pipe and damper therefor, appertaining particularly to a motor-actuated damper for a smoke pipe that is provided with an automatic draft regulator.

In heating plants such as intermittently fired oil furnaces and the like that call for considerable draft and high stack temperatures, there is substantial heat loss during the period when the fuel burner is not operating. To lessen such loss, as by the entrapment of useable heat in the furnace and the reduction of entrainment of warm air from the building that must be replaced by colder air draw in from outside, it is found desirable to employ a motoractuated damper that is under thermostatic control, opening in advance of the igniting of the furnace and closing after an appropriate time delay following the cessation of the burner operation. Mitigating against the full effectiveness of such a heat-saving damper is the need to provide also an automatic draft regulator in the smoke pipe to maintain a relatively constant draft through the furnace by admitting room or outside air to the smoke pipe in response to pressure differential.

Accordingly it is an object of this invention to provide a smoke pipe line between a furnace and the chimney with a motor-actuated damper and an automatic draft regulator responsive to the velocity of the flue gases and the pressure thereof relative to that of the air in the room, wherein the damper operates between the draft regulator and the chimney.

A further object of the invention is to provide a smoke pipe line running between the furnace and chimney with a motor-actuated damper controlling a flow of gases through the smoke pipe line and an automatic draft regulator bleeding a flow of atmospheric air from the room to the smoke pipe line proportionate to the velocity of the flue gases and the pressure differential of the air in the flue and room wherein the damper is inserted in the smoke pipe line between the draft regulator and chimney the damper and smoke pipe line being so constructed and assembled as to prevent entrainment of warm air from the building when the damper is closed and yet prevent escape of flue gases into the room.

A further object of the invention is to provide a novel automatic draft regulated smoke pipe and damper assembly of the nature and for the purpose described wherein the automatic draft regulator may operate freely and independently when the damper is open but is biased in closed position when the damper is closed.

A still further object of the invention is the provision of the herein described novel automatic draft regulated smoke pipe and damper assembly that is characterized by structural simplicity, durability and low cost of production and installation and being capable of safely effecting substantial saving in fuel costs is thereby rendered commercially desirable.

To the accomplishment of these and related objects as shall become apparent as the description proceeds, the invention resides in the construction, combination and arrangement of parts as shall be hereinafter more fully described, illustrated in the accompanying drawings, and pointed out in the claims hereunto appended.

The invention will be best understood and can be more clearly described when reference is had to the drawings forming a part of this disclosure wherein like characters indicate like parts throughout the several views.

Patented Feb. 22, 1966 In the drawings:

FIGURE 1 is a side view of a conventional oil fired furnace with a smoke pipe running to the chimney embodying the present invention;

FIGURE 2 is an enlarged plan of the novel smoke pipe thereof showing the location of the dampers and draft regulator; and

FIGURE 3 is a further enlarged sectional detail of the counterbalanced draft regulator and damper in the branch pipe.

Referring now particularly to the drawings, it will be seen that FIGURE 1 illustrates a furnace F such as a conventional oil burning unit with a smoke pipe P running to the chimney C. The pipe is provided with a novel lateral pipe fitting in open communication with the flue and having an open port controlled by a freely operable automatic draft regulator normally subject to the velocity of the flue gases and the pressure differential in the smoke pipe and the room. A motor-actuated damper is also installed in the flue. It may consist of a valve controlling passage of gases through the flue, operating through degrees as from closed to open position by a motor. A suitable motor circuit under the influence of a thermostat circuit-closer and serving also to complete the circuit to the furnace burner motor with suitable time lag is disclosed in my Patent 3,010,451 granted November 28, 1961.

The motor-actuated damper is normally closed as when the oil burner of the furnace is not operating but when the thermostat signals need for more heat it closes the circuit to the damper motor and opens the same after which the burner igniter and motor are in action operation. Whilst the furnace burner is operating and the damper remains open, the draft regulator operates independently and automatically to bleed room air into the flue to equalize the draft through the furnace, when the furnace burner has shut off and after a sufiicient time lag to permit the furnace to be purged of volatiles and fumes the damper closes arresting further draft through the furnace and thereby retaining the heat therein. The use of such a motor-actuated damper has been found to effect a substantial saving in fuel costs.

With the normal motor-actuated damper and automatic draft regulator arrangement wherein the automatic draft regulator lies between the damper and the chimney, however, much war-m room air is drawn off through the draft regulator during the periods when the furnace buner is not operating and such warm air must be replaced by cold air sucked or infiltrating in from outside the building. To overcome this wastage of heat the position of the automatic draft regulator and the motor-actuated damper may be reversed, with the damper between the draft regulator and chimney and thus the closing of the damper valve after the furnace burner has shut off serves both to retain the after-fire heat in the furnace and to bar drawing off warm room air through the draft regulator because of the damper being positioned between the draft regulator and the chimney. In this case, however, the possibility of furnace gases seeping out through the draft regulator while the closed damper valve denies passage up the chimney presents an ever present danger.

Accordingly, my preferred structure and assembly as shown herein utilizes a novel form of smoke pipe with an automatic draft regulator and a dual valve damper to accomplish the desired end without any of the dangerous or unwanted features as hereinbefore suggested. Accordingly, I employ lateral pipe fitting as here shown in the form of an elbow 8 with a length of cylindrical pipe 9 running toward the furnace, i.e., against the direction of flow, parallel with the flue P and terminating in an open port 10 in which a conventional counterbalanced automatic draft regulator 3 is disposed. An elongated pivot shaft 6a runs across both the elbow extension pipe 9 and the smoke pipe P and traverses the space between and carries two damper valves a and 5b in the pipes 9 and P respectively with just one motor unit 7 engaging either end of the shaft 6a. Thus it will be readily seen that when the damper is open the draft regulator is free to operate unimpeded yet when the damper is closed the wastage of heat from the furnace and the drawing off of warm room air through the draft regulator are both prevented by the damper valves 5b and 5a respectively and the escape of furnace fumes through the port 10 is likewise barred.

From the foregoing description taken in connection with the accompanying drawings, it will be manifest that a smoke pipe and damper therefor is provided that will fulfill all the necessary requirements of such a device, but as many changes could be made in the above description and many apparently widely different embodiments of the invention may be constructed within the scope of the appended claims, without departing from the spirit or scope thereof, it is intended that all matters contained in the said accompanying specification and drawings shall be interpreted as illustrative and not in a limitative or restrictive sense.

What is claimed as new is:

1. A smoke pipe adapted to run from a furnace to a chimney and having a lateral air admission branch with an open inlet port, a pair of normally closed dampers in said smoke pipe and air admission branch respectively, electrically operable motor means for operating said dampers in unison from a position in which the dampers are both closed to a position in which the dampers are both open, an automatic draft regulator means in the open port of said branch normally subject to the imbalance of pressure in the pipe and the atmosphere when the pair of dampers are open and biased in closed position when the dampers are closed.

2. A smoke pipe adapted to run from a furnace to a chimney and having a lateral air admission branch with an open inlet port, said lateral branch paralleling said pipe and extending toward the furnace, a normally closed automatic draft regulator controlling said port, a damper comprising a pair of valves disposed one in each of said pipe and branch respectively and having an elongated common pivot shaft extending through both said pipe and branch and carrying both said valves and electrically operated means for said damper, whereby said valves are caused to operate in unison from a position in which the dampers are both closed to a position in which the dampers are both open, and wherein the damper valve in the pipe lies between the furnace and the lateral branch and the damper valve in the branch lies between the draft regulator and the chimney.

References Cited by the Examiner UNITED STATES PATENTS 762,913 6/1904 Kitchen 126293 X 1,943,342 1/1934 Mortimer 126293 2,508,885 5/1950 Maekay 158-28 2,877,834 3/1959 Campbell 158-28 X JAMES W. WESTHAVER, Primary Examiner.

Claims (1)

1. A SMOKE PIPE ADAPTED TO RUN FROM A FURNACE TO A CHIMNEY AND HAVING A LATERAL AIR ADMISSION BRANCH WITH AN OPEN INLET PORT, A PAIR OF NORMALLY CLOSED DAMPERS IN SAID SMOKE PIPE AND AIR ADMISSION BRANCH RESPECTIVELY, ELECTRICALLY OPERABLE MOTOR MEANS FOR OPERATING SAID DAMPERS IN UNISON FROM A POSITION IN WHICH THE DAMPERS ARE BOTH CLOSED TO A POSITION IN WHICH THE DAMPERS ARE BOTH OPEN, AN AUTOMATIC DRAFT REGULATOR MEANS IN THE

Images