Seal for bleeder valves
US 3126028 A
Abstract available in
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Description (OCR text may contain errors)
March 24, 1964 N. T. KURFISS 3,126,028
SEAL FOR BLEEDER VALVES Fi lllll ril 13, 1961 INVENTOR. NEAL T. K UUUU ss,
allay Y ATTORNEYS United States Patent 3,126,028 SEAL FOR BLEEDER VALVES Neal T. Kurfiss, Middletown, Ohio, assignor to Armco Steel Corporation, Middletown, ()hio, a corporation of Ohio Filed Apr. 13, 1961, Ser. No. 102,832 7 Claims. (Cl. 137-329.!)1)
The invention relates to the solution of problems connected with the provision of bleeder valves for blast furnaces.
As is well known, the top portion of a blast furnace is normally provided with a plurality of uptakes which serve as exit means for the furnace gases. These uptakes are interconnected by a manifold having a downcomer for conducting the furnace gases to a solids separator and thence to a gas washer. The uptakes at their tops are provided with bleeder valves which are either manually or automatically operated for the purpose of relieving sudden pressure excesses inside the furnace.
The gases from the blast furnace are at an elevated temperature and have large quantities of finely divided and highly abrasive solids entrained in them, so the gases are known as dirty gases. When a bleeder valve is opened, the rush of the abrasive-laden gases past the separated valve tappet and seat cuts and scores these elements, permitting leakage when the valve is again closed.
Once a bleeder valve begins to leak, the cutting action proceeds very quickly because of the channeling of the abrasive-laden gases.
Thus it is necessary frequently to replace the active parts of the bleeder valves, which is a source of great expense and inconvenience, and which cuts down the productive capacity of the furnace since the conventional valve can be repaired or replaced only when the blast is taken ofi the furnace.
It is an object of this invention to provide a valve structure which is not subject to erosion as described above, or in which erosion is greatly minimized.
It is an object of the invention to provide a bleeder valve with an effective seal of the compressive type which will compensate for erosion for a substantial length of time.
It is an object of the invention to provide a bleeder valve with two seals whereby the elements forming one seal can remain in closed position during the repair and replacement of the elements forming the other seal, so that such repair and replacement can be carried on without opening the valve and hence without taking the blast off the furnace.
These and other objects of the invention which will be set forth hereinafter or will be apparent to one skilled in the art upon reading these specifications are accomplished by that certain construction and arrangement of parts of which an exemplary embodiment will now be described. Reference is made to the accompanying drawings wherein:
FIGURE 1 is a vertical sectional view of a typical bleeder valve to which the present invention is applied.
FiGURE 2 is a partial enlarged sectional view showing the specific coaction of the tappet and seat members.
FIG. 3 is a partial sectional view of the elements 8 and 19, illustrating the element 19 as metal.
The particular valve illustrated in FIGURE 1 is of a type in which the tappet moves away from the seat in a downward direction. Types of bleeder valves in which the tappet moves upwardly away from the seat are equally well known. The skilled worker in the art will understand, in the light of the teachings herein, how the invention may be applied to either type; and indeed in FIGURE 2 hereof the right hand element may be considered either a part of the tappet or the valve seat part of the body, while the left hand element may be considered either the seat or the tappet as the case may be.
In FIGURE 1, the upper end of an uptake is indicated at 1. The bleeder valve includes a bowl-shaped casting surmounted by a cast element 3 of annular form which serves as the valve seat. A shaft 4 is journaled in brackets (one of which is shown at 5) on the bowl, and carries a lever arm 6 which is pivoted to a riser portion 7 of a valve tappet 8. A projecting end of the shaft 4 carries a lever arm 9, counter-weighted as at 10 and provided at its other end with an operating cable 11. Within the bowl 2 there may be guide elements 12 for the movement of the tappet 8. As thus far described, the bleeder valve is conventional.
FIGURE 2 shows the coaction of the parts forming the seal of this invention. As explained above, this figure shows the two opposite valve parts; and while the lefthand part has been illustrated to comport with the showing of the tappet 8 in FIGURE 1, with the right hand part comporting with the valve seat portion 3, these parts may be reversed, so that the member 8 becomes a part of the body of the bleeder valve and the membelr 3 becomes a part of the tappet.
As illustrated, one of the valve parts, in this instance 8, is characterized by a downwardly and inwardly sloping surface 13, above which there is a recess 14. The
other valve part 3 is configured opposite the surface 13 so as to present a nose 15. A separate and removable metallic member 16 in the form of an annulus, lies on and is held to the member 3 as by bolts 17. This separate metallic member is also configured to present an annular nose 18 lying opposite the recess 14. The recess 14 contains a member 19 having a surface 19a coasting with the nose 18 on the member 16. In the practice of the invention, the member 19 may be made of various substances including metal; but preferably it is made of resilient, heat-resisting substance, and will first be so described.
The shape of the recess 14 may be that shown or may be varied within the limits of shapes which will hold the resilient member 19, the cross section of which may also be changed; but the resilient member will have a surface 1% generally coplanar or nearly so, with the surface 13. The recess may have a slight overhang as at 14a in order to assist in retaining the resilient member.
The resilient member may be made of natural rubber, any of the synthetic rubbers, or of chloroprene such as neoprene. Preferably it is made of a material resistant ,to oxidation at somewhat elevated temperatures; and best results have been obtained through the use of silicone rubber. As exemplary, a silicone rubber having a dur ometer hardness of 50 plus or minus 5, a tensile strength of 825 pounds per square inch and an elongation of 350% has been found very serviceable.
FIGURE 2 illustrates the positions of the parts upon the first contact of the nose 18 of the separate metallic member 16 with the resilient member 19. When the valve is fully closed, the member 8 may occupy the position shown in FIGURE 2 in dotted lines, in which position the nose 18 will have deflected the resilient member 19 to a degree as will be evident. In the fully seated position, the nose 15 preferably lies against the surface 13; but with the resilient member 19 compressed and deflected by the nose 18. The exact extent of the deflection is not a necessary limitation on the invention; but in an exemplary embodiment the deflection is about /4 inch. In testing for the desired heat resistance and resiliency under heat, a suitable material for the resilient member 19 after being tested for twenty-four hours at a temperature of 350 F., with a deflection of 4 inch, showed a permanent set no greater than inch.
The valve of this invention thus forms a gas-tight seal stood that the recess 14 is annular.
between-the metallic nose 18 and the resilient substance 19 which prevents the escape of the dirty furnace gas. Hence there will be no fiow of gas through the valve when the valve is closed; and the seal will be effective despite any slight erosion of thenose 18 during the relatively brief intervals when the valve is open.
However, the valve parts of this invention are readily renewed without shutting down the furnace or decreasing the furnace top pressure. It will be seen in FIGURE 2 that the member 16 may be removed upon removal of the bolts 17. A seal or closure will still be maintained by the engagement of the nose 15 with the surface 13. The member 16 when removedor drawn to one side, will completely uncover the recess 14. The resilient substance 19 may then be removed from the recess and a fresh piece of resilient substance inserted. It will be under- The resilient substance 19 is preferably handled in the form of a strip of indefinite length. 'It may be laid in the recess, and its ends may be cut so as to come together therein preferably under slight compressive pressure. Further, it is possible to replace the entire member 16, if it is desired.
While a resilient and compressible member 19 is pre ferred, it is possible to use other substances (see FIG. 3). A ring of metal may be placed in the recess 14 (the overhang 14a being eliminated). It is also possible to form the annular member 19 from a strip of bendable metal in the way hereinabove described for the use of a strip of resilient substance. Certain of the advantages of the invention may be obtained even if the recess 14 and member 19 are omitted and the surface 13 of member 8 continued to coact with nose 18 as well as nose 15.
Modifications may be made in the invention without departing from the spirit of it. The invention having been described in an exemplary embodiment, what is claimed as new and desired to be secured by Letters Patent is:
1. In a bleeder valve construction, a body, relatively movable metallic members serving respectively as a valve seat and a valve tappet, one of said members having a substantially conical surface with an annular recess located intermediate the edges thereof and adapted to contain a renewable valve seat structure, a body of resilient substance Within said annular recess, the other of said members being configured to provide a first nose positioned for valving coaction with the surface of said first mentioned member, and a second nose coacting with the surface of said resilient substance, the said second nose being formed on a metallic body removably mounted upon the valve member having said first nose, the parts being so related that when said metallic body is removed from said valve members, the said annular recess in the first mentioned valve member will be uncovered for removal and replacement of the body of resilient substance therein.
2. The structure claimed in claim 1 wherein the resilient substance is a rubbery composition of heat resistant charnular recess except for such surface coacting with said second nose.
4. In a bleeder valve construction, a body, relatively movable metallic members serving respectively as a valve seat and a valve tappet, one of said members having a substantially conical surface with an annular recess located intermediate the edges thereof, and containing a renewable valve seat structure, the other of said valve members having a pair of noses for effecting valve sealing contacts, one of said noses being formed on a metallic body removably mounted upon said other valve member, the parts being so related that when said removable member is removed, the said annular recess will be uncovered for the removal and replacement of the said renewable valve seat structure.
5. In a bleeder valve construction, a body, relatively movable metallic members serving respectively as a valve seat and a valve tappet, one of said members having a substantially conical surface with an annular recess located intermediate the edges of said conical surface and containing a renewable valve seat structure, the other of said members being configured to make valve-closing contact both with said renewable structure and with said conical surface, that portion of the said other of said valve members which makes valve-closing contact with said renewable structure being located on a metallic body removable from the said other valve member and so c0nfigured that, when so removed, it will uncover the said annular recess to permit renewal of the renewable valve seat structure located therein while the said bleeder valve remains otherwise closed.
6. The structure claimed in claim 5 wherein the said renewable valve seat structure is formed of a distortable substance.
7. In a bleeder valve construction, a body, relatively movable metallic members serving respectively as a valve seat and a valve tappet, one of said members having a substantially conical surface, the other of said members having a surface configuration such as to effect valveclosing contact with said first mentioned member in substantially concentric annular areas, one of said members having an annular recess containing a renewable valve seat structure, and the other of said members having a removable annular portion, the parts being so related that when said removable portion is removed, the said annular recess will be uncovered for removal and replacement of the renewable valve seat structure, while the valve otherwise remains in closed position.
References Cited in the file of this patent UNITED STATES PATENTS 1,665,394 Willoughby Apr. 10, 1928 2,418,200 Smith Apr. 1, 1947 2,657,897 Folmsbee Nov. 3, 1953 2,949,127 Malina Aug. 16, 1960 2,982,515 Rule May 2, 1961 2,995,057 Nenzell Aug. 8, 1961 FOREIGN PATENTS 549,291 Canada Nov. 26, 1957