US3076578A

US3076578A - Furnace plug mechanism

Info

Publication number: US3076578A
Application number: US31880A
Authority: US
Inventors: Hosea E Smith; Thurman V Dodson
Original assignee: Exxon Research and Engineering Co
Current assignee: ExxonMobil Technology and Engineering Co
Priority date: 1960-05-26
Filing date: 1960-05-26
Publication date: 1963-02-05
Anticipated expiration: 1980-02-05

Description

Feb. 5, 1963 H. E. SMITH ETAL FURNACE PLUG MECHANISM Filed May 26. 1960 2 Sheets-Sheet 1 FIG.

FURNACE TUBES elk INVENTORS. HOSEA E. SMITH,

BY THURMAN V. DODSON,

FIG.3.

ATTORNEY.

Feb. 5, 1963 H. E. SMITH ETAL FURNACE PLUG MECHANISM 2 Sheets-Sheet 2 Filed May 26, 1960 INVENTORS. HOSEA E. SMITH, THURMAN V. DODSON,

United States Patent I 3,076,578. FURNACE PLUG MECHANISM Hosea E. Smith, Highlands, and Thurman V. Dodson, I

This invention relates to furnaces such as those commonly used having tubes therein filled with oil or other fluids which are heated for use in chemical processes, More particularly, this invention is an improved plug member which can be removed to permit the entrance of mechanical cleaning tools into the heating tubes in order to clean these tubes.

In using furnaces for heating oils or other fluids, the oil is fed into a series of tubes arranged inside the combustion chamber. Adjacent tubes are connected at the ends by devices known as headers. Oil is flowed through tubes and headers and is then flowed from the furnace. In this manner, the oils or other fluids are heated and then flowed to other devices used in the processing of the oil.

During the heating, coke forms in the heating tubes and these tubes are also subject to corrosion. This formation of coke and corrosion requires that the tubes in the furnace be intermittently cleaned to remove the coke and corrosion.

To permit the entrance of cleaning tools into the tubes, ports or holes are provided in the headers at various points in the tube system. The ports are plugged by plug members when the tubes are being used. To clean the tubes, the plug members are removed and cleaning tools inserted to remove the coke and corrosion.

It often happens that the plugs stick to the headers and are extremely hard to remove. In these instances, pry bars, levers, and hammers are first used in efforts to remove the plugs. This mechanical abuse often mutilates the plug beyond reuse and also often fails to loosen the plug. As a last resort, heat is applied to the headers in the plug area to expand the header away from the plug. Although heating usually works, it is very dangerous. Oil is often trapped in the tubes in the vicinity of the plug and when heat is used to remove the plug, this creates a great fire hazard.

This invention provides the art with a new furnace heating tube plug mechanism which is simple in construction and can be installed in place of the plugs which are currently used for such heating furnace headers. These new plugs can be easily removed and thus the use of pry bars, levers, hammers, and heating need not be resorted to. Thus, the mutilation of the plug beyond reuse and the fire hazard are eliminated.

The invention as well as its many advantages will be further understood by reference to the following detailed description and drawings in which:

FIG. 1 is a schematic, elevational view, partly in section, showing the arrangement of the tubes in a typical furnace for heating oil;

FIG. 2 is a view taken along lines 22 of FIG. 1;

FIG. 3 shows the arrangement of the flow path through the vertical tubes of the furnace;

FIG. 4 is an enlarged view taken along lines 4-4 of FIG. 3 showing the construction of the new plug mechanism; and

FIG. 5 is a view taken along lines 5-5 of FIG. 4.

Referring to the drawings in which like parts are referred to by like numerals, a furnace is shown having a bottom portion 12 which is supported above the earths surface by means of supports 14. Heat is applied to the combustion chamber of furnace 10 by means of a burner 3,076,578 Fatented Feb. 5, 1963 2. such as gas jet 16 which is arranged in the center of the bottom of the furnace 10.

Fluids such as oil are flowed into the furnace 10 and through the tubes 18 wherein they are heated by the heat in the combustion chamber of the furnace 10 and then flowed from the furnace 10 to other areas where they are further processed. The tubes are provided with bends or

headers

22 and 20 at the top and bottom of the furnace 10 so that there is a continuous flow path through the tubes 18.

Referring to FIG. 3, the top portions of the tubes 18 include return bends or headers 20 which are afiixed to the tops of two adjacent tubes. The bottoms of the tubes 18 are connected by means of the lower bends or headers 22 which are atfixed to the two adjacent bottom portions of the tubes 18.

When it is desired to clean the tubes 18 after the formation of coke and/or corrosion has occurred, plugs such as indicated generally by the numeral 24 in FIG. 3 may be removed from the

headers

20 or 22. Cleaning members can beinserted through the exposed ports in the headers in order to clean the internal surfaces of the tubes 18.

It often occurs that very minute particles of coke or other matter get between the outside perimeter of the plug and the plug seat. At the high temperatures and pressures, galling also occurs in this same area. Such conditions cause these plugs to be removed only with difficulty. As formerly stated, when pry bars or other types of mechanisms are used to remove the plugs, the plugs can no longer be used due to excessive mutilation of the plugs. Also,- since oil is often trapped in the area of the plug, if heat is used to remove the plug, there is a great fire hazard. 1

Referring to FIG. 4, which is an enlarged sectional view taken along lines 4-4 of FIG. 3, it is seen that the header 22 is provided with an inwardly and upwardly" tapering plug seat 30. In conventionally utilized plugs, a solid plug member is inserted to mate with the plug seat 30. It is this type of plug which often sticks and is difiicult to remove.

Rather than use a single solid plug which mate against the seat 30 of the header, this invention utilizes an annular insert member 32. Insert member 32 has its outside perimeter shaped to sealingly engage the seat 30. The inside diameter of the annular member 32 is substantially constant throughout its length and the inside diameter is large enough to permit cleaning tools to be inserted through the insert 32 and up through tubes 18. The annular insert 32 is provided with a downwardly facing annular shoulder 34.

A removable solid plug 36 is used to plug the hole defined by the insert 32 when fluids are being heated in the tubes 18. The plug 36 is provided with an upwardly facing annular shoulder 38 which is adapted to mate with the shoulder 34 of the insert 32 and separated from insert 32 by means of a substantially fiat annular metal sealing gasket 40. The shoulder 38 on plug 36 is substantially the same size as the shoulder 34 on insert 32. Notice also that the plug 36 is provided with a short upright section 42 which comes into contact with the inside perimeter of the annular insert 32. This, along with the gasket 40, provides a sealtight engagement of the plug member with the insert 32. The upper portion of the plug 36 tapers upwardly and inwardly towards its axis and extends into the annular insert 32.

The solid plug 36 is held releasably pressed against the annular metal sealing gasket 40 by means of a threaded bolt 44. The end of the threaded bolt 44 presses against a bolt seat 46 provided centrally within the plug 36. Bolt 44 is threaded through a holding member 48 which has extending portions 50 which extend through ports 52 provided in downwardly extending cars 54. When the bolt 3 44 is screwed upwardly (looking at FIG. 4), the end of the bolt forces plug 36 into tight engagement with insert 32 and also the holding member 48 is forced downwardly against the lower portion of the ports 52 in ears 54.

Of course, as the oils within tubes 18 are heated, a high temperature and pressure are developed within the tubes 18. The metal gasket 40 is a leak-free seal. The gasket is also strong enough to remain in place despite the high temperatures and pressures within the tubes 18. The gasket also absorbs any unevenness between the insert 32 and the plug 36 due to extreme heating.

The plug 36 is tapered in its upper part to provide a space 56 between the tapered portion of the plug 36 and the inside diameter of the insert 32. Thus, any coke which tends to form within the heating tubes 18 will fall in the space 56. This will prevent sticking of the plug within the insert 32.

The plug 36 is removed simply by loosening the bolt 44, moving one of the extending portions 50 from its port, turning the holding member 90", and removing the bolt, holding member, plug, and gasket from the ears 54.

If it should happen that the insert 32 sticks to the seat 30 because of the formation of coke between the insert 32 and the seat 30, this insert member may be left in the seat 30 and need not be removed. The plug, gasket, and other members will fall of their own weight and can be easily removed.

The insert 32 need only be used when it is desired to substitute this new type plug mechanism for existing plugs now used in conventional heating furnaces. Of course, with new furnaces, if the headers are provided with a seat conforming in shape and dimension to the shoulder 34 so that the insert 32 is made an integral part of the

headers

20 or 22, it would be unnecessary to use a separate insert and the remaining parts of the system disclosed herein can be used.

We claim:

1. In combination with a heating member having an opening of substantially constant diameter permitting cleaning tools to be inserted therethrough and a pair of ear members extending from the heating member and diametrically spaced about said opening, each of said ear members having a port formed therein, and said heating member being provided with an annular plug seating shoulder adjacent said opening: a removable solid plug having an annular shoulder adapted to seat on said seating shoulder, the entire end of the removable solid plug located outside of said heating member being substantially fiat and the portion of the solid plug extending into said opening of substantially constant diameter tapering inwardly toward its axis from a point adjacent said plug shoulder; a substantially flat annular metal sealing gasket adapted to fit between said seating shoulder and said plug shoulder with the dimensions of said seating shoulder, said plug shoulder, and said flat annular metal sealing gasket being substantially the same; a holding member having a central portion and diametrically spaced outwardly extending portions, each of the extending portions being adapted to extend into a port in an ear member, said central portion of the holding member being provided with a threaded bore extending therethrough; and a threaded bolt adapted to extend through said threaded bore and coaxial with the solid plug to press against the solid plug.

2. The combination of claim 1 wherein said plug is provided with a bolt seat.

References Cited in the file of this patent UNITED STATES PATENTS 590,584 McKeone Sept. 28, 1897 1,841,523 Crowe et a1 Jan. 19, 1932 1,981,061 Moorhead Nov. 20, 1934 2,046,029 Muchnic June 30, 1936 2,309,122 Keenan Jan. 26, 1943 FOREIGN PATENTS 679,366 France Jan. 9, 1930

Claims

1. IN COMBINATION WITH A HEATING MEMBER HAVING AN OPENING OF SUBSTANTIALLY CONSTANT DIAMETER PERMITTING CLEANING TOOLS TO BE INSERTED THERETHROUGH AND A PAIR OF EAR MEMBERS EXTENDING FROM THE HEATING MEMBER AND DIAMETRICALLY SPACED ABOUT SAID OPENING, EACH OF SAID EAR MEMBERS HAVING A PORT FORMED THEREIN, AND SAID HEATING MEMBER BEING PROVIDED WITH AN ANNULAR PLUG SEATING SHOULDER ADJACENT SAID OPENING: A REMOVABLE SOLID PLUG HAVING AN ANNULAR SHOULDER ADAPTED TO SEAT ON SAID SEATING SHOULDER, THE ENTIRE END OF THE REMOVABLE SOLID PLUG LOCATED OUTSIDE OF SAID HEATING MEMBER BEING SUBSTANTIALLY FLAT AND THE PORTION OF THE SOLID PLUG EXTENDING INTO SAID OPENING OF SUBSTANTIALLY CONSTANT DIAMETER TAPERING INWARDLY TOWARD ITS AXIS FROM A POINT ADJACENT SAID PLUG SHOULDER; A SUBSTANTIALLY FLAT ANNULAR METAL SEALING GASKET ADAPTED TO FIT BETWEEN SAID SEATING SHOULDER AND SAID PLUG SHOULDER WITH THE DIMENSIONS OF SAID SEATING SHOULDER, SAID PLUG SHOULDER, AND SAID FLAT ANNULAR METAL SEALING GASKET BEING SUBSTANTIALLY THE SAME; A HOLDING MEMBER HAVING A CENTRAL PORTION AND DIAMETRICALLY SPACED OUTWARDLY EXTENDING PORTIONS, EACH OF THE EXTENDING PORTIONS BEING ADAPTED TO EXTEND INTO A PORT IN AN EAR MEMBER, SAID CENTRAL PORTION OF THE HOLDING MEMBER BEING PROVIDED WITH A THREADED BORE EXTENDING THERETHROUGH; AND A THREADED BOLT ADAPTED TO EXTEND THROUGH SAID THREADED BORE AND COAXIAL WITH THE SOLID PLUG TO PRESS AGAINST THE SOLID PLUG.