US1869442A

US1869442A - Furnace pressure regulator

Info

Publication number: US1869442A
Application number: US530995A
Authority: US
Inventors: Steinbart Alfred
Original assignee: Individual
Current assignee: Individual
Priority date: 1931-04-17
Filing date: 1931-04-17
Publication date: 1932-08-02
Anticipated expiration: 1949-08-02

Description

Aug, 2, 1932. A. STEINBART FURNACE PRESSURE REGULATOR Filed April 17, 1931 2 Sheets-Sheet l Aug. 2, 1932. A. STEINBART FURNACE PRESSURE REGULATOR 2 Shets-Sheet 2 Filed April 17. 1931 144156550 57Z7/V54ET, v

Patented Aug 2;. 1%32 entree ALFRED STEWART, @F PITTSBURGH, PENNSYLVANIA FURNACE PRESSURE REGUEATOR Application. filed April 17, 1931. serial No. 530,995,

This invention relates to furnace pressure regulators and while not limited thereto, relates more particularly to means for and method of maintaining a balanced pressure in open-hearth furnaces and the like.

in the operation of opemhearth and similar furnaces it is desirable to maintain the same pressure in the hearth as the atmospheric pressure outside in order to economize on fuel and to develop the highest temperature. l V hen thepressure in the furnace is less than atmospheric, cold air will flow into the furnace through the doors and other openings and cool the hearth, but if the pressure in the furnace is higher than atmospheric the hot gases will leak out through the openings and be lost-0 The outflow of hot gases from the furnace damages the door frames and other parts with which they come in contact and also are objectionable in the buildings in which the furnaces are located.

A balanced pressure in a furnace is a pressure in the furnace the same as the atmosr pheric pressure outside.

The present invention has for its object the provision of means for automatically controlling the furnace draft so as to maintain a balanced pressure in the furnace.

in the drawings:

Figure 1 is an elevation of apparatus constructed in accordance with this invention.

Figure 2 is an enlarged fragmentary view, partly in section, of the furnace or hot end of the apparatus.

Figure 3 is an enlarged View, partly in section, of the cold end of the apparatus.

Referring more particularly to the drawings, the numeral 2 designates an openhearth furnace which is provided with an opening 2 in its wall through which. hot gases may escape from the furnace and air may enter the furnace in accordance to unbalanced pressure between the interior of the furnace and the atmosphere.

A pipe 3 is mounted in the opening or port 2* and is provided with a port or orifice 3 in its side wall which communicates with the hot end of a suction tube a which is provided with a restriction wall 5 adjacent its other or cold end, having an outlet orifice 5 therein similar to the orifice 3. The orifices 3 and 5 are only a fraction of the diameter of the tube or pipe 4. The pipe e continues beyond the ,IQStIlCtlOIl wall 5 and is connected to a conduit 6 having a valve 6* therein.

The conduit 6 communicates with a suction header 7 which may, serve a plurality of suction tubes from diherent furnaces, if desired.

The suction in the header 7 is created by a (5 station 18 which includes a steam jet enhaust-e'r 1? controlled by a valve 20.. The valve 20 is automatically controlled by

rods

21 and 21 connected to an oil-sealed bell 19. The bell'l9 is located'in a vessel 22 which is connected by a T-titting 25 to the pipe26 which is, in turn, connected to the header 7. The rod 21 carries a counterweight if the suction created by the enhauster l7 acting on the bell l9 overcomes the combined weights of the bell and counterweight 23, the bell rises and the

rods

21 and 21 operate the valve 20 to throttle the suction, thereby maintaining a constant suction in the header .7.

A by-pass conduit 8 is provided between the suction tube or pipe l and the conduit 6 and is provided with a valve 8 The suction in the tube or pipe l is adapted to be communicated through a pipe 9, having a valve 10, to an oil-sealed bell 12 which is carried on one end of a scale beam 12*. The other end of the scale beam carries an oil-sealed bell 12 which is open to the atmosphere through a pipe 29. The end of the beam 12 on which the bell 12 is carried is also anchored to a fixed point of the housthe suction acting on the bell 12 and it is so adjusted that it keeps the scale beam 12 in a horizontalofr balanced position when the temperature of gases entering the inlet ori lice 3 is about 1000 degrees Fahrenheit.

The scale beam l2 is connected by

levers

30 and 31 to a valve 32 of a compressed air motor 13 which has its piston rod is con- All?) nected by a cable or rope 15 to the damper 16 in the draft flue 16 of the furance 2.

In operation, with the by-pass valve 8 closed and the valve 6 open suction from the header 7 will draw gases or air from the conduit 4 through the orifice 5 This suction will cause a flow of gases or air through the inlet orifice 3 into the suction tube 4. The suction in the pipe or tube 4 will increase until the same weight of gas enters into the tube 4 through the orifice 3 as is withdrawn through the orifice 5*. After this equilibrium is established the suction in the tube 4 remains constant as long as the suction in the header 7 remains constant and the tem-.

perature of the gases flowing through both orifices 3 and 5 remains constant. The teniperature at the outlet orifice 5 is atmospheric and, therefore, may be considered constant for practical purposes. The temperature at the inlet orifice 3 however, varies very much as at times the hot gas from the furnace flows to the inlet orifice and at other times cold air which is drawn into the furnace and passes through the pipe 3 flows to the inlet orifice. Furnace gases and air have substantially the same density at atmospheric temperature but the gases at say 2000 degrees Fahrenheit have only 21 per cent. of the density of atmospheric air. As a result, much lessvweight of gases enters the inlet orifice when hot furnace gases are entering and, therefore, the suction in the tube 4 rises immediately and drops again when cold air enters.

The suction in the tube or pipe 4 is communicated through the pipe 9 to the bell 12. The variation in the suction or tension of the gas or air in the tube 4 therefore rocks the scale beam 12 which in turn operates the valve 32 of the air motor 13 through the

rods

30 and 31. The operation of the valve 32 controls the motor 13 to open or close the damper 16 in the draft flue 16*.

When the pressure in the furnace rises and the hot gases issue from the furnace through the opening 2'* and pipe 3 the suction in the tube 4 rises, the bell 12 lowers and the motor 13 opens the damper 16, and when the pressure in the furnace goes below atmospheric pressure cold air passes into the furnace through the pipe 3, the suction in the tube 4 drops and the bell 12 rises and the motor 13 is o erated to close the damper 16.

The action of the damper is gradual and the apparatus is so arranged that the damper does not overrun its proper position. The valves 6 and 8 are provided for hand control of the damper during bottom'making in the furnace 2. By closing the valve 6 and hand manipulating the valve 8 the motor 13 can be controlled to operate the damper 16 at will.

While I have shown and described one specific embodiment of my invention it will aeeaaea be understood that I do not wish to be limited thereto since various modifications may be made without departing from the scope thereof, as defined in the appended claims.

I claim: J L

1. The method of automatically maintaining balanced pressure in a furnace, which consists in allowing hot gases from the furnace to issue from an opening when the pressure in the furnace is above atmospheric pressure and allowing cold air to stream into the furnace through the said opening when the pressure in the furnace is below atmospheric pressure and using the variation in density of the hot furnace gases and cold air passing through said opening to regulate the draft.

2. The method of automatically maintaining balanced pressure in a furnace, which consists in allowing hot gases from the furnace to issue from an opening when the pressure in the furnace is above atmospheric, and allowing cold air to stream into the furnace through the said opening when the pressure in the furnace is below atmospheric pressure, drawing the air and hotfurnace gases successively through spaced orifices in a confined fiow path causing the hot gases to cool to atmospheric tempera-' ture between said orifices so as to vary the suction in said flow? path and using the varia-.

tion in suction to operate valves for the regulation of the draft.

3. The method of automatically maintaining balanced pressure in a furnace which consists in allowing hot gases from the furnace to issue from an opening when the pressure in the furnace is above atmospheric pressure and allowing cold air to streain into the furnace through said opening when the pressure in the furnace is below atmospheric pressure, drawing the air and hot furnace gases successively through spaced orifices in a confined flow path of sufficient length to permit the hot furnace gases to cool to substantiall atmospheric temperature between said 011- fices so as to increase the suction in said flow path when hot furnace gases are passing therethrough materially above the suction when air is passing therethrough, and using the variations in suction in said flow path to regulate the furnace draft.

4. The combination with a furnace having an opening therein through which hot gases will issue rom the furnace when the furnace is operating above atmospheric pressure and through which cold air will flow into the furnace when the furnace is operating below amospheric pressure, of a draft damper for controllin the draft to said furnace, and a suction tu e having one end in communication with said opening and its other end material distance from said opening so to maintain said last named end at substantially atmospheric tempere ure, said tube having relatively small restr.cted orifices jacent its ends, means for creating a constant suction at the end of, said tube remote from said furnace to cause a flow of the air and hot furnace gases flowing through said opening into said tube through the orifice at the furnace end thereofand out through the orifice at the end remote from said furnace, whereby the suction in said tube will vary with the variations in temperature of said air and hot gases, and means operable by the suction in said tube for automatically operating said draft damper.

5. The combination with a furnace having an opanin therein through which hot gases will issue mm the furnace when the furnace is operating above atmospheric pressure and through which cold air will flow into the furnace when the furnace is operating below atmospheric pressure, of a draft damper for controllin the draft to said furnace and a suction tu e having one end in communication with said opening and its other end remote from said opening so as to maintain said remote end at substantially atmospheric temperature, said tube having relatively small restricted orifices adjacent its ends, means for creating a constant suction at the end of said tube remote from said furnace to cause a flow of the air and hot furnace gases flowing through said opening into said tube through the orifice at the furnace end thereof and out through the orifice at the end remote from said furnace, whereby the suction in said tube will vary with the variations in temperature of said air and hot gases, a fluid motor for operating said draft damper, a valve for controlling said motor and means operable by the suction in said tube for automatically operating said valve.

my hand.

ALFRED STEINBART.

In testimony whereof, I have hereunto set