Apparatus and method for sealing coke oven doors

A coke oven door has a primary seal that includes a first metal knife edge in contact with a door jamb first sealing surface, and a secondary seal that includes a second metal knife edge in contact with a door jamb second sealing surface. The plenum or space between the sealing knife edges is maintained at super atmospheric pressure by flowing coke oven gas into the plenum. In a modification of the invention, the secondary seal includes a metal strp in contact with an elastic material; the plenum between the sealing surfaces being also pressurized above atmospheric pressure and purged of coke oven gas.

BRIEF SUMMARY OF THE INVENTION 
Seals of a coke oven door acting on a door jamb create a plenum that is 
pressurized by introducing coke oven gas thereinto. The primary seal is a 
metal band contacting the door jamb and the secondary seal is either a 
metal to metal engagement or a metal to silicone rubber engagement. 
During the coking coke oven gas at slightly higher than ambient pressure is 
introduced into the plenum. When it is necessary to remove the door, the 
coke oven gas is removed by evacuation means, and ambient air replaces the 
coke oven gas. 
In one embodiment of the invention the primary seal does not exist around 
the entire periphery of the door. In another embodiment of the invention 
the primary and secondary seals extend around the entire periphery of the 
door. For a further understanding of the invention and for features and 
advantages thereof, reference may be made to the following description and 
the drawing which illustrates a preferred embodiment of equipment in 
accordance with the invention.

DETAILED DESCRIPTION 
Referring to FIG. 1, a portion of the coke oven door 11 and door jamb 13 
are shown in juxtaposition with a primary door seal 15 and a secondary 
seal 17 in operative position. 
The primary door seal 15 includes an elongate ribbon 19, having a knife 
edge 21 that is of conventional form that contacts a primary sealing 
surface 23 on the door jamb 13 as shown. 
The ribbon 19 is secured to the frame portion 25 of the coke oven door 11 
by means of an elongate bar 27 which is doweled to the door frame portion 
25 of the coke oven door 11. The elongate bar also coacts with a Z-form 
bar 29 having at one end a knife edge 31 that coacts with a secondary 
sealing surface 33 of the door jamb 13. A plurality of bolts 35, nuts 37, 
and wedge-type clamps 39, as shown in FIG. 1, hold the ribbon 19 and 
Z-form bar 29 in position horizontally. The ribbon 19 and Z-form bar 29 
have elongate holes so that each bar may be adjusted vertically, as viewed 
in FIG. 1. 
The ribbon 19, bar 27 and Z-form bar 29 extend along the two vertical sides 
and along the bottom edge of the door frame 25, but only the bar 27 and 
the Z-form bar extend along the top edge of the door frame. the ribbon 19 
is not present at the top of the door frame 25. The ribbon 19 terminates 
on both sides of the door at elevation A--A of FIG. 3. Level B--B 
represents also the approximate level of the coal being coked in the oven 
chamber. A section through the door sealing mechanism at the top of the 
door 11 is shown in FIG. 4 wherein it will be seen that only the secondary 
seal 17 is present. 
It will be noted that when the door 11 is in place and when both knife 
edges 21, 31 are in contact with their respective sealing surfaces 23, 33, 
there exists a plenum 41 that is open to the oven chamber above the coal 
line A--A in the chamber. A conduit 43 connects with a passageway 45 in 
the door jamb 13 so that a purging gas, such as clean coke oven gas, 
flowing in the conduit 43 and passageway 45, fills the plenum 41. Since 
the plenum is open at the top, the purging gas flows into the oven above 
the coal line. The gas pressure in the plenum 41 in maintained at a 
relatively low pressure, such as about 10 mm of water column above 
atmospheric pressure. 
The primary seal 15 prevents coal from blocking the plenum 41, and if the 
plenum can be kept open, the pressure therein, acting on the secondary 
seal 17, can be kept low, at the value indicated previously, even when the 
oven is being charged initially. 
The purging gas is optional. It is not intended that the purging gas in the 
plenum will prevent raw coke oven gas from entering the plenum, flowing by 
the primary seal 15. The gas pressure in the plenum 41 is purposely low 
since the plenum is open at the top. The purging gas acts as a sweeping 
medium to minimize the concentration of dirty gas in the plenum and to 
reduce the tar condensation. Wherefore, the coke oven door and door jamb 
can be more easily cleaned. 
FIG. 2 shows a portion of a coke oven door 47 to which are attached a 
primary seal 49 and a secondary seal 51 with a door jamb 53. 
The primary seal 49 includes a Z-form bar 55 having a conventional knife 
edge 56 that is secured to the door frame portion 57 of the door 47 by a 
cap screw 59 and Belleville type spring 61, as shown in FIG. 2. The Z-form 
bar 55 has elongate holes through which the cap screws pass so that the 
Z-form bar can be adjusted vertically, as viewed in FIG. 2. Adjustment of 
the Z-form bar 55 is made by turning a bolt 63 extending through the door 
frame portion 57. A sealing type lock nut 65 is threaded onto the bolt 63 
to seal the threaded opening through the door frame portion 57 and to keep 
and maintain the bolt 63 in a desired position. 
The door frame portion 57 is provided with a channel member 67 having an 
arm extension 69 which is connected to the frame portion 57 by a plurality 
of cap screws 71 or the like. The channel member 67 is filled with a 
suitable resilient material 73, such as silicone rubber, or the like. 
In juxtaposition to the channel 67 and to the resilient material 73, there 
is attached to the door jamb 53 an angle-shaped member 75 that is fitted 
with a shoe 77 that engages the resilient material 73 when the door 47 is 
installed on the oven battery. The angle-shaped member 75 is secured to 
the door jamb 53 by means of a plurality of cap screws 79, or the like. 
It will be seen from FIG. 2, that, whenever the door 47 is installed on the 
oven battery, the primary and secondary seals 49, 51 respectively create a 
plenum 81; the seals 49, 51 in this instance, however, being complete 
around the enitre periphery of the door 47. 
In FIG. 2 there are shown two conduits 83, 85 passing through the door 
frame 53. The conduit 83 is located at the top edge, of the door 47, 
preferably on the top centerline, and the conuduit 85 is located near the 
bottom edge of the door 47. 
The upper conduit 83 includes a vent valve 87 near the top of the door 
that, when actuated in any suitable manner, purges the plenum 81 of any 
gas-air mixture that may be therein and that relieves the plenum of 
positive pressure, so that the door 47 can be safely removed. 
The vent valve 87 is connected to two conduits 89, 91 which carry any such 
gases away from the plenum 81 is described hereinafter. 
The conduit 85 is fitted with a branch line 93 that is in communication 
with the plenum 81 on the other side of the door 47, opposite the conduit 
85. Whereby, the flow of gases into and from the plenum 81 through the 
conduit 85 also takes place through conduit 93. 
Also, the conduit 85 is fitted with a three-way valve 95 that is connected 
to three conduits, 97, 99 and 101, that carry gases into and away from the 
three-way valve 95, as described hereinafter. 
During the coking operations, the primary 15 and the secondary 17 seals 
around the door 11 effectively prevent leakage of gases to the atmosphere. 
Coke oven gas flows in the conduit 43 and passageway 45 into the plenum 
41. As mentioned previously, such coke oven gas flow into the plenum is 
optional, but when it is used it does maintain the plenum at a slight 
pressure, about 10 mm of water column above atmospheric pressure. The coke 
oven gas entering the plenum flows into the oven chamber since the primary 
seal 15 does not exist across the top of the door. The flow of coke oven 
gas in the conduit 43 is shut off of course, when it is necessary to 
remove the coke oven door before pushing commences. 
Considering FIG. 2, in which case both the primary seal 49 and the 
secondary seal 51 are complete around the entire periphery of the coke 
oven door, during coking, raw coke oven gas flows in conduits 97, 85, 93 
into the plenum 81; the three-way valve 95 being normally open and the 
valve 87 being normally closed. Coke oven gas in the plenum 81 creates a 
pressure of about 10 mm of water column above atmospheric pressure that 
causes coke oven gas, if any, to flow into the coke oven chamber in the 
direction of arrow A. 
When coking in the chamber is completed, and it is necessary to remove the 
doors on the chamber, the valve 87 is opened so that the coke oven gas in 
the plenum 81 flows in conduit 89 into the gas collecting main of the 
battery. At the same time, valve 95 is positioned so that coke oven gas 
flowing in conduit 97 is stopped and so that air flowing in conduit 101 
flows into the plenum 81. After a few minutes time has elapsed, when 
nearly all of the coke oven gas has been removed from the plenum, the 
valves 87 and 95 are positioned so that whatever gases remain in the 
plenum flow in conduits 91 and 99 such conduits being in communication 
with a steam ejector or the like device. 
Thereafter, the door can be removed without the hazard that any coke oven 
gas in the plenum might flare up and burn. It is to be noted that the door 
47 of FIG. 2 is not removed in the same manner, which is conventional, as 
the door 11. Instead, the door 47 is moved away from the face of the oven 
on a horizontal level, without first lifting the door in the conventional 
manner. After the pad has become disengaged from the elastic seal 
material, then can the door be lifted as necessary. When the door is 
replaced, it is first moved toward the oven in a horizontal direction, 
with no vertical movement unitl the pad and seal engage. 
After the door has been replaced, the plenum 81 is purged with air flowing 
thereinto through valve 95 and conduits 101, 85 and 93. The air flows out 
of the plenum through valve 87 and conduit 91 to atmosphere. Thereafter, 
valve 87 is closed and valve 95 is so positioned that coke oven gas under 
slight pressure, as mentioned above, flows in conduits 97, 85, 93 into the 
plenum. Whereupon, coking commences and proceeds in a normal manner with 
the plenum under a slight super-atmospheric pressure of coke oven gas. 
From the foregoing description of one embodiment and a modification of the 
invention, those skilled in the art should recognize many important 
features and advantages of it, among which the following are particularly 
significant: 
That the double seals, primary and secondary, insure double protection 
against leakage of gas to the atmosphere; 
That the secondary resilient material seal is effective in preventing 
leakage of coke oven gas to the atmosphere in cases where the primary 
metal seal leaks; and 
That the purge gas system creates a flow of gas toward the into the coke 
oven chamber, thereby carrying with it any particulate matter that might 
collect in the plenum. 
Although the invention has been described herein with a certain degree of 
particularity it is understood tht the present disclosure has been made 
only as an example and that the scope of the invention is defined by what 
is hereinafter claimed.