US2518314A

US2518314A - Valve construction for regenerative furnaces

Info

Publication number: US2518314A
Authority: US
Inventors: Hellan Haakon
Original assignee: Individual
Current assignee: Individual
Priority date: 1947-12-08
Filing date: 1947-12-08
Publication date: 1950-08-08
Anticipated expiration: 1967-08-08

Description

g- 8, 1950 H. HELLAN 2,518,3l4

VALVE CONSTRUCTION FOR REGENERATIVE FURNACES Filed Dec. 8, 1947 3 Sheets-Sheet 1 INVENTOR. HAAKON HELL/1N BY ATTORNEY 3 Sheets-Sheet 3 H. HELLAN VALVE CONSTRUCTION FOR REGENERATIVE FURNACES Aug. 8, 1950 Filed Dec. 8, 1947 IN VENT OR HAAKON HELL AN ATTORNEY Patented Aug. 8, 1950 UNITED STATES PATENT OFFICE 2,518,314 VAL E CONSTRUCTION FOR REGENERATIVE FURNACES HaakonHellan, Cleveland Heights, Ohio Application December 8, 1947,.seria1 No. 790,314

(circa-45) 5 Claims.

This invention relates to regenerative furnaces such as open hearth furnaces for production of steel; and more specihcally'relates t'o" valves used for controlling the new" of air' and waste gas through" the regenerative heat transfer units to and" from the open hearth furnace.

As is well known, an openhearth furnace usually has associated with it two or niore different regenerative chambers operatively con nected to the open hearth furnace so that air can be forced through one of such regenerative chambers and then to' the open hearth" furnace after Which the" waste gases" flow through the second regenerative chamber and out to the at= mosphere through a chimney. The operation is such that one regenerative chamber is heating the input air'whil'ethe second" regenerative chamber is absorbing heat'fronr the' waste gases passing therethro'u gh. The flow through the regenerative chambers is periodically reversed so that the heat stored in one'c'haniber canbe used for preheating the input air, accordingly, easily operated valves must be provided to control the flow of air and" gas therethrough; These regenerative chambers are" heated tohigh temperatures bythelarge volume of gasespassin'g therethrough so that the valve means not only must be of appreciablesize but must be adapted to withstand high temperatures, as well as wide fluctuations in temperature.

The valve" means usually include an air valve at'floor level for admitting air to a regenerative chamber, and a due damper to' control the how of waste gas from the regenerative chamber to the chimney flue and stack. One commonly used construction-at present has theflue' damper con"- nected to a saucer valve with a limited vertical movement for opening and closing relation The flue damper connects to the to its seat. saucer valve by a flexible rope on opposite sides of a sheave. The rop'e' slackens when the saucer Valve closeson its seat and. the weight of the air valve ceases to pull on the flue damper which always is suspended through suitable sheave means from an operating mechanism. Usually L.

there are two sets of air valves and flue dampers provided for each openhearth furnace with one set being associated with each regenerative chamber. Hencethe mechanism used to operate the sets of air valves and the flue dampers must be adapted to function under variable load conditions-and to take up slack in the flexible rope connecting the air valve and flue damperaft'er the air valve seats on the valve seat provided therefor.

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Another problem relating to valves.- for open hearth regenerators is that the hood provided over the damper is usually designed for being positioned at the arch level. Furthermore, on modern furnaces have deep flues their re generative systems so'that deep pits must be provideo. inthefloor for access to the cooling pipes used for the valves. I

The present invention is particularly concerned withthe type of flue damper that has a seat with a single horizontal opening therein for registering with a flue having an independent vertical air inlet; as distinguished from the double decked type of damper construction wherein the air inlet is through a second horizontal port im me'diately above the flue, and where the one damper will close both to stack or air alternatingl'y; A very serious problem in present valve construction is caused by the change in practise fr'om'using natural air sucked in at the air valves to the use of forced air of considerable pressure as furnished by a fan, and introduced at the same air valves; which then are enclosed incens ings. The flue damper slides on the seat with the face toward the stack flue. The injection of forced air behind the damper will cause it to sway from the seat, leakcold air into the stack and kill the draft. The situation in the double decked construction is similar at the up er port, where the small weight component of the damper is far insufficient to balance the air pressure behind it.

The general" object of the present invention is to avoid and overcome the foregoing and other difliculties with the present type of valve con structions for regenerative furnaces and to provide a valve asseinblywith a positive'correlatlon between the action of the air valve and hue damper and a positive closing force against the seat of both damper and air valve.

Another object of the invention is to provide opposed suspension.

Another object of the invention is to design the damper and air valve so that the air valve can operate onexactly one-half the movement of the damper to simplify theconnectionof the means correlating their movement. v

A further object of the invention is to extend the seat for the damper up to the floor lever and toassociate the same fiiredly with the hood providing for the air transmittal means.

Yet another object of the invention is top'ro vide a hood for covering an openingin the flue arch and to utilize this opening as a vertical passageway for transmitting air to the flue.

Another object of the invention is to use separate, vertically movable gate valves for controlling the air fiow to each regenerative chamber of a furnace.

A still further object of the invention is to provide a damper, the cooling pipes for which serving as the valve stem of the damper.

Yet another object is to provide a forced draft system for a regenerative furnace with a common blower for a plurality of regenerative chambers and with straight connecting ducts for the fast flowing air.

Another object of the invention is to provide flue dampers with novel dry web'construction for withstanding severe temperature changes so as to avoid warping and to benefit from air cooling by the inflowing air.

1 These and other objects of the present invention will become more apparent and better understood from the following detailed description taken in conjunction with the accompanying drawings; wherein Figure 1 is a plan view of a portion of a regenerative unit and of valve means therefor embodying the principles of the present invention; Figure 2 is a vertical section view taken on line 2-2 of Figure 1 with additional control means therefor shown in diagrammatic form; Figure 3 is a front elevation of the damper and cooling pipes therefor of the invention; and i Figure 4 is a vertical section taken on line 4-4 of Figure 3.

Reference now is made to the details of the construction shown in the accompanying drawings wherein numerals I and 2 designate regenerator fiues which lead from the furnace regenerators (not shown) and into a common flue 3- that extends to a waste heat boiler or chimney. The fiues I and 2 are usually provided with arched top portions. In order to force air into the regenerators when desired, a conventional blower or fan indicated by the number 4 is provided on the floor above the fine 3. The blower I is driven by a conventional motor 4a and forces air into a 'junction tank 5 which has air outlet ducts 9 and I9 connected thereto. The junction tank 5 is shown as provided with a removable top 6 which may be readily opened to permit the flow of air into the intake ducts in the event of failure of the fan 4 or motor 4a.

- Each air duct 9 and I 0 is provided for connection to one of the furnace regenerators and connects thereto through corresponding means, one example of which is best shown in Figure 2. The. air ducts 9 and i0 connect to hoods ii and I2 that are positioned over vertically extending passages I6 that connect the hoods individually to the fines I and 2 with which they are associated.

. Air flow through the air ducts 9 and it is controlled by means of gate valves I and 8. The valves I and 8 each include a ribbed cast iron 7 gate I3 which is slidably associated with a cast ment in a vertical plane so that they can be moved from positions without the ducts to positions within the ducts for controlling or preventing air flow through the same. The casing sections I5 have upwardly extending extensions tea for receipt of the gates I3 in their open positions.

Flow of waste gases from flues I and 2 into the common fine 3 is controlled by means of dampers, such as a damper Il that is slidably mounted'against a seat within the flue I. This damper I? is provided with a water cooled rim substantially as is shown in my prior Patent 2,648,696. The lower portion of the damper web consists of a separate, replaceable alloy metal plate I8 which is secured to the damper Ii by bolts liiaextending through enlarged bolt holes in the plate. Thus, the independent damper plate can contract and expand appreciably in relation to the damper frame, with a minimum of warping or buckling of the same since the temperature of the damper plate varies widely. The damper I7 is slidably positioned on a cast iron seat [9 provided therefore, which seat is water cooled in a similar manner to the damper by means of cooling coil 20a. Water or other cooling means is carried to the seat I9 by means of a pipe 20 which extends through the hood ii and is exhausted therefrom by a pipe (not shown) that usually extends along the opposite wall of the passage I6.

Figure 3 best shows that a cooling coil 36 is provided in the damper N. This damper i! may .have a plurality of ribs Ila provided on its upper outer surface for contact with air flowing into the regenerator unit. These ribs Ila are usually cast integral with the remainder of the damper. Similar ribs may be provided on the alloy plate I8. V V

So as to maintain the damper I"! at reduced temperatures, two pipes 2i connected to the coil 36 extend therefrom and pass through holes in a cover section 22 removably associated with the hood II. The pipes 21 have a plate 23 secured thereto-adjacent their upper ends, which plate is used in suspending the damper and in controlling the position of the same. Guide'ineans, such as substantially vertically extending guide bars 59a, are associated with the cast iron damper seat It and extend therefrom in the plane thereof up to a point adjacent the floor level of the apparatus. These guide devices I9a provide means on which the damper H can be slidso as to open the fines I and 2 to flue 3.

Movement of the damper IT is controlled through means of a conventional motor 28 which has 'a drum 2? associated therewith to receive a flexible rope 25 which in turn connects to'an eye-bolt 2t secur'edto the plate 23. The flexible rope 25 passes over a sheave 26 and connects to a counterweight 29-, which counterweight is adapted to balance, substantially, the damper I1 less the support'provided thereforby the gate I3, as hereinafter explained in detail; The plate 7 23 also carries an' eye-bolt 30 that connects to a second conventional flexible rope M. This rope 35 extends over a support sheave 32 and secures to an adjustable eye-bolt 3A. A sheave 33 is supported by the rope 3I intermediate the support sheave 32 and anchor member as and pletely open to a completely closed position. By suspending the gate. valve I3 in the manner shown, it is. balancing atleast a. portion oi the weight." of the damper IT at all times; and the positions of" the gate valve and the damper are made interdependent so that one can only be olbsed when the other isopen and vice. versa. Of course; the damperancl gate valve must move simultaneously; which 'is-an'other requisite in controlling air flow through a regenerator unit.

Flexible hose 38 is shown attached to the ends. of-thepipes 2| for transmittal of cooling fluid to and from such pipes for transmittal to the damper H. The plate 23 supports the damper IT as previously indicated, through the pipes 2|, and eliminates the use of a central rod, which has heretofore been used in corresponding damper constructions.

From the foregoing, it will be seen that a novel type of damper is provided that is especially suited for wide fluctuations in the temperature to which it is subjected. Likewise, a positive relationship between the damper and air valve is provided, and the two valves are suspended in constant opposition whereby the weight of the air valve will assist in balancing the damper and there will be an efiective interlock therebetween to maintain the two devices in proper operative correlation.

Having thus described my invention so that persons skilled in the art may understand and practice the same, what I desire to obtain by Letters Patent is embodied in the appended claims.

I claim:

1. An open hearth reversing system comprising regenerator fiues converging into a stack flue, flue dampers for closing said regenerator flues, a blower for furnishing air under pressure to the regenerator flues, horizontally disposed ducts leading from sa d blower to the said regenerator flues, a vertically movable and constantly suspended gate valve for closing each air duct, flexible means uniting said flue dampers to said air valves, means for correlating the movement of said flue damper with the movement of said air valve, said air valve having approximately half of its weight constantly acting in opposition to said flue damper, a counter weight connected to said. flue damper for balancing the remaining weight thereof, and mechanical means for raising and lowering said flue damper and thereby closing or opening said air valve dependin upon the position of said flue damper.

2. An open hearth reversing system for regenerator flues which converge to a stack flue, a vertical air passage into each of said regenerator flues, a flue damper seat provided in each of said vertical air passages adjacent the junction of said regenerator flues, a flue damper positioned on said damper seat, a blower for supplying air under pressure to the regenerator flues, an air duct connecting said blower with said vertical air passage above the regenerator flues, a vertically movable gate valve in said air duct for controlling the flow of air to said vertical air passage. and means operatively connecting said vertically movable gate valve to said damper for permitting air flow through said air duct only when said damper is closed.

3. A valve system for a regenerative furnace having fines extending therefrom and joining into a common discharge flue, said apparatus comprising an air duct connecting to each of the flues extending from the regenerative furnace, blower means for forcing air through said air ducts, said air ducts being joined together adjacent to said age-am blower means; a gate va lve for each air duct freely movable invertical planes from an open to closed position, a damper seat provided in each flue, a damper associated with each of said damper seats. and. being adapted for movement in a substantially vertical plane for movement from a closed to an open position, a flexible rope connected to each of said dampers and to anele vated support member, the associated gate valve being completely suspended from a sheave in a.v

loop. of said. flexible rope between said. support.

member'and' a sheave above the damper, whereby the operation" of' said air valve is dependent upon the position of said damper, the one acting and moving in opposition to the other said gate valve being arranged to seat under air pressure from said blower.

4. A. valve system for a regenerative furnace including two regenerator flues extending therefrom and connecting to a common collecting flue, said apparatus comprising an air duct leading from each of the flues, blower means for forcing air through said air ducts, said air ducts being joined together adjacent said blower means, a air valve with vertical seat for each air duct,

said air valves being movable .in vertical planes from open to closed positions and adapted to seat under air pressure irom said blower, a damper seat provided in each regenerator flue and positioned adjacent the connection thereto of said air duct but intermediate same and said collecting flue, a damper associated with said damper seat and adapted in a substantially vertical plane for movement to and from an open position, a flexible rope connected to said damper for operat ng said air valve, fixed means for support ing the other end of said rope, a support sheave engaged with said flexible rope intermediate said fixed means and said damper for supporting said air valve and damper in o position, a second flexible rope attached to said damper, a drum receiving said second rope. and means for controlling the position of said drum for controlling the vertical positions of said damper, and said air valve being adapted to move from open to closed osition with one-half the vertical movement of said damper.

5. A valve system for a regenerative furnace having flues extending therefrom and connecting with common collecting flue, said a para us comprising an air duct leading from each of the fines. blower means for forcing air through said air ducts, said air ducts being joined to ether adiacent said blower means air valve with vertical seat for each air duct, said air valves being movable in vertical planes from open to closed osition and adapted to seat under air pressure from said blower. a damper sea-t provided in each regenerator flue positioned adjacent the connection thereto of said air duct. a damper assoc ated with said damper seat for movement in a substantially vertical plane for movement to and from a fine closing position. a flexible rope connected to said damper for operating said air valve, means for fixedly supporting the other or said flexible robe, a support sheave engaged with flexible rope intermediate said supporting means and damper, said air valve and damper being coupled by said flexible rope so that the weights thereof are in opposition and positions of same are correlated and one of such members is closed when the other such member is open, a second flexible rope attached to said damper at one end and a counter weight at the other end to balance the pull from the 7 said damper, a rope drum positioned intermediate said damper and said counterweight, and means for rotating said drum.

7 HAAKON HELLAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date Re. 15,552 Knox Mar. 6, 1923 354L990 Christie July 6, 1895 Number 10 Number Name 7 Date.

, Knox Sept 7, 1920 Knox Sept. 7, '1920 Byrssen June 23, 1931 Nye Oet.'6, 1931 King et a1 May 30, 1933 Naismith et a1 June 30, 1933 FOREIGN PATENTS Country Date France July 14, 193':