US1556810A

US1556810A - Mechanism for operating the reversing valves of regenerative furnaces

Info

Publication number: US1556810A
Authority: US
Inventors: Turner Charles Prentice
Original assignee: Individual
Current assignee: Individual
Priority date: 1921-11-02
Filing date: 1921-11-02
Publication date: 1925-10-13
Anticipated expiration: 1942-10-13

Description

Oct. 13,1925. 1,556,810

C. P. TURNER MECHANISM FOR OPERATING THE REVERSING VALVES OF REGENBRATIVE FURNACES Filed Nov. 2, 1921 T-Sheets-Sheet 1 qvihuoo Oct. 13,1925.

C. P. TURNER MECHANISM FOR OPERATING THE REVERSING VALVES OF REGENERATIVE FURNACES I Sheets-Sheet 2 Filed Nov.

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.M w W M v w W n M m Oct. 13, 1925' 3 C. P. TURNER IECHMIISI POI OPBRATIIG THE REVERSING VALVES OF REGENERATIVE FURNACES Filed Nov. 2. 1921 Sheets-SheetS 54044 KW MW.

Oct- 13, 1925. 1,556,810

c. P. TURNER IIICi'lANISl FOR OPERATIIG HIE REVERSING VALVES 0F REGBNBRA'IIVE FURNACES Filed NOV. 2, 1921 3| venioz M FE m qvflneoo T4: I

Wf MM Oct. 13-, 1925- 6. 10

C. P. TURNER IECHANISI FOR O?ERATING THE REVERSING VALVES OF REGENERAT'IVE FURNACES Fild Nov. 2, 1 '7 Sheets-$heet 5 MKW ' C. P. TURNER NECHANISI FOR OPERATING THE REVERSING VALVES 0F REGENBRATIVE FURNACES Filed Nov. 2, 1921 Sheets-Sheet 6 Patented Oct. 13, 1925.

UNITED STATES CHARLES PKE'NTICE TURNER, F STELLTON, PENNSYLVANIA.

MECHANISM FOR OPERATING THE BEVEB-SING- VLLVES OE REGENERA'IIVE Z URIEACES.

Application filed November To all no: em it may com/r12 Be it known that I, CHARLES Piuix'ncn Truman, a citizen of the United States. and residing at Steclton, Dauphin County, State of Pennsylvania, have invented certain new and useful Improvements in Mechanism for Operating the Reversing Valves of Regenerative Furnaces, of which the following is a specification.

The present invention relates to mechanism for operating the reversing valves of regenerative furnaces.

In operating regenerative furnaces and particularly open hearth furnaces, it is customary to supply producer gas and air through separate conduits to the hearth or combustion chamber where these gases interniingle and burn, the hot products of combustion passing out through two similar passages from the opposite end of the furnace to the stack or first to one or more waste heat boilers to the stack and thence to the atmosphere. Each of the four passages has an enlargement or chamber in which is located checker work, of well known type, and each passage is adapted to serve as either an inlet passage or outlet passage. The hot gases of combustion passing through the two passages serving as outlet passages. heat the checker chambers, and after the charm bers are sufficiently heated the direction of How of gas and air to, the furnace is reversed, the producer gas and air then flowing through the checker chambers which have just been heated by the exhaust gases, so that before they reach the combustion clmmber their lel'i'iperatures have been raised to a. high degree. The former gas and air inlet passageways have now become outlet conduits for the burned gases, a large proportor.- of the heat of these gases being absorbed bfv the checker chambers. Reversal of the 'l'urnace talres place usually at regular intervals of time, such rcversalbeing effected by the manipulation of certain valves which control the flow of gas and air to the combos lion chamber and the flow of hot products oi" combustion to the stack.

At the instant of reversal the gas and air inlet passages contain considerable quantities 0t unburned gas and air which has been heated in the checker chambers to a high temperature, and if precautions are not taken this gas and air will mix in the tines leading to the stack or in the stack itself and cause an explosion. Such explosions Serial No. 512,503.

is are vented From passin-gto the stack until th i burned ses have escaped all nossilnlitv or explosion is avoided.

It is the object o f the present invention to provide mechanism wherebv the valves oif a regenerative furnace may be aiiitomaticall; opened and closed upon reversal of the :lurnace in such sequence that this intermingling 0t hcate'c gas and air in the \va heat boiler or adjacent Fluesis prevents... The mechanism is electrically operated and is cont led bv a master switch, which is the only member to be manually o u-rate'u to ctl'or-t the reversal. the remainder oi tl operation be ng entirely automatic. il valves are all mechanically connected to a single motor which is controlled by the masttcr switch. The mechanical connections bc tween the valves and motor are such that the valves ar operated in proper sequence as the motor revolves in one direction.

In my copending application, Serial No, 512.304; tiled Nov. 9, 1921, is disclosed mechanism of a somewhat similar character that in v. iih the valves are provided with individual motors for operating the same, which motors are controlled by a single mas ter switcl'i and a circuit making and breaking device. in certain instances it is necessary or desirable to emp is, individual niotors while in other instances a single motor and mechanical connections between the mo tor and valves preterablc.

The invention has many novel features as will be apparent to one skilled in the art as is disclosed in the tollowing descriptions and in the t.QQO1IiD1l'iU{ drawingiss. in which Figure 1 is a top plan view of tho inlet and outlet valves of a regenerative turnace, portions oeinp; broken :1 my to show th chcc ccr chambers:

Figures 7?. and l are sections on the lines f3-il: -3: ilirespectively o't Fit"- 1 me i.

Figure 5 is a top plan view, partly broken away, of a portion of the valve operating mechanism;

Figure 6 is a front elevation of the same showing diagrammatically certain of the electrical circuits;

Figure 7 is a section on the line 7-7 of Figure 6;

Figure 8 is a section on line 8-8 of Figure 6;

Figures 9 and 10 are sections on lines 9-9 and 10-10 respectively of Figure 6;

Figure 11 is a side view of a portion of a modified form of the valve operating mechanism;

Figure 12 is a similar view of another portion of this modified mechanism;

Figure 13 is a series of diagrams showing the relative positions of the valves and the sequence of movements followed in effecting a reversal; and

Figure 14 is a diagrammatic view of an electromechanical mechanism for retarding the speed of the operating motor temporarily duringthe reversal.

The hearth or combustion chamber of the furnace is not illustrated in the drawings but it will be understood that the

flues

10, 11, 12 and 13 shown in Figure 1 are the gas conducting flues, the enlargements 10', 11', 12 and 13 of these flues constituting the checker chambers, although the actual checker work is not illustrated. The flues 10 and 11 may serzfilas gas and air inlet flues respectively, in ich case both flues 12 and 13 serve as outlet flues for the hot products of combustion. After a reversal of the gas flow flues 12 and 13 serve as air and gas inlet flues respectively and flues 10 and 11 as outlet conduits for the products of combustion.

Each of these flues has, at its forward end, two control valves, one of which controls the flow of fresh gas or air as the case maybe to the furnace and the other controls the flow of products of combustion to the stack or waste heat boiler. These valves are illustrated diagrammatically in Figure 1, the valves G and G controlling the flow of gas into flue 10 and the hot products of combustion out of this flue, and the valves A and A respectively control the flow of air into the flue 11 and the hot products of combustion out of this flue to the stack. The valves on the opposite side of the furnace are similarly arranged and are indicated at A, A, G" and G. The main gas supply flue is shown at 14, the gas intake to this flue being illustrated at 15, and the stack is indicated at 16. Dampers 17 and 18 respectively are provided for blocking passages 19 and 20 for conducting the hot products of combustion to the stack so that these products of combustion may be caused to pass through valve controlled each of the valves on the right hand side of the furnace is provided with a vertically disposed stem, the upper end of which is pivotally hung from a valve operating lever. These valve operating levers are indicated at L, L, M, and M respectively. The valve operating mechanism on the left hand side of the stack is not illustrated, but

it will be understood that such mechanism is an exact duplicate of the mechanism illustrated. Each of levers L, L, M and M' has one end rotatably mounted upon a long shaft 24 which is in turn rotatably supported in the framework.

Upward and downward movement of the levers -just mentioned results in the open ing and closing of the valves and this move ment is brought about by the operation of a large motor R mounted on the framework and which is mechanically connected to each of the valve levers. This motor is connected by means of a chain and gear to the shaft 26, which is in turn geared to the shaft 24. The shaft 24 is geared to two

countershafts

27 and 28 so that rotation of the motor R results in rotation of these countershafts, though at greatly reduced speed.

The countershaft 27 has a crank arm fixed to each end, these crank arms extending in diametrically opposite directions. The right hand crank arm 29 has a connecting rod 30 pivotally secured thereto, this connecting rod having a spindle-like end portion 30' which passes through an openin in a short cross piece 31 rotatably secure to lever L. The reduced extension 30 of the connecting rod is adapted to slide through the opening in this cross piece, the limits of this sliding motion being determined by the relative positions of the shoulder 30 and nut 30 at the outer end of the connecting rod. It will be seen that rotation of countershaft 27 through a complete circle will effect the raising and lowering of lever L but that, due to the lost motion of the connecting rod, the valve Gr will be in its lowest position, or seated, during the time that the crank arm 29 is in the lower part of its swing and will only be raised when the crank arm is in the upper part of its swing.

In Figure 8 the crank arm 32 is illustrated in dotted lines and is illustrated near the top of its swing, the lever L being raised and the valve G unseated, as shown in Figure 6. Countershaft 28 is provided with similar crank

arms

33 and 34 respectively which are connected by connecting nuts and 36 to levers M and M respectively. In this instance however the crank arms 33 and 3' are not diametrically opposite but are arranged at an angle to each other. The positionof the crank arm 34 corresponds substantially to that of the crank arm 29 while the crank arm is about 60 behind the crank arm 32, the direction of rotation being indicated by the arrows in Figures 7 and 8. \Vhile countershafts 27 and 28 are not connected to each other, yet they are driven at the same angular velocity by shaft Qt. and the various crank arms occupy, at all times, the same angular relationship to each other. The interval of time during which each of the valves remain in closed position depends upon the design of the connecting rod, that is upon the amount of lost motion between the crank arm and the operating levers and the motor speed, while the sequence of operation of the valves depends upon the direction of rotation of countershafts 27 and 2S and upon the angular relationship which the several crank arms bear to each other. As the countershafts are driven in the direction of the arrows it will be seen that the "alves (l and A will be opened and closed si taneously while the valve A will be opened considerably later than gas valve G thus permitting the hot gas to escape through the boiler to the stack before the hot air liberated. Crank 32 passes its dead center in advance of the crank 33 and the lost motion connection between the connecting rod 35 and the lever M so designed that the period during which valve G is open and valve A closed, is of considerable duration.

The electric circuits for controlling the operation of the motor R are illustrated in l igure (3. The motor armature is indicated at and its field at 41. Lead wires to a suitable generator are indicated at and it will be seen that the circuit through the armature is controlled by a switch. This switch comprises a stationary contact l3 and a moving contact 44 which also constitutes the armature of an electro-magnet \Vhen this electro-magnet 45 is energized it artracts the armature 4st and closes the circuit through the motor armature l0. As soon as the magnet 4:5 is deenergized, however, the circuit through the armature it) is broken and at the same time a resistance 40 thrown into action, the switch member 44 being moved by a spring 47 so that its opposite end is thrown into contact with a stationary contact 48. The resistance 46 brings about a braking influence tending to immediately stop the motor armature from rotating.

A main or master switch is indicated at Q and two stationary contacts at 4:9 and 50. The switch plate S may be brought into contact with either of the stationary contacts. Mounted upon shaft 27 is a cylindrical drum 5i of insulating material having mounted upon its outer surface two

semicylii'idrical contact plates

52 and 53. Spring contacts 54, 5G and 57 have their ends resting against this cylinder, contacts it and be ing adapted to brush against moving contact 53 as the cylinder is revolved and contacts 5G and 57 being adapted to engage moving contact- Co-ntacts and 53 are on diametrically opposite sides of the drum 51 but each extends slightly more than onehalt of the distance around it. Spring contacts and 57 are electrically connected to the negative terminal of the generator (not illustrated} and spring contacts 54: and 56 are connected to contacts 4-9 and 50 respectiveiy.

Assuming the switch S to be in its full line position it will be seen that a circuit will be completed through electro-magnet d5 pr vided that sprin contacts 56 and 57 are electrically connected by contact 52. The switch blade 44: will then be operated and the circuit closed through motor R. Rotation of cmmtershaft 27 then commences and this rotation will continue until this shaft has turned through 180, when contact 52 will move from under contacts 56 and 57 thus breaking the circuit and stopping the motor. Rotation of the countershaft 27, and the other countershafts, through 180 effects a reversal of the valves. Contact is then engaged by spring contacts 5% and and it only remains for the operator to shift the switch S to its dotted line position to again energize magnet 45 and effect a second reversal of the valves. The drum 5]. therefore constitutes an automatic circuit breakingdevice which breaks the circuit when the valve reversal is completed. EX- cept for the operation of the switch 6 the operation of the mechanism is entirely automatic and requires no expert knowledge or manual assistance on the part of the furnace operator, who simply effects the reversal at certain predetermined times.

In Figure it; the (li rams (I, 5, e, (Z, c. and f/ iihist 'elaiiie positions of the valves in two complete reversals. in the diagram a, the valves A" and (i are shown to be open and valves .Q and G closed. (in the opposite side of the furnace the valves A and ti are closed while valves (l and and -U are open. ll'hen the switch S is ooerated the lirst result of the movement motor It is to lower the valves ti, At. A I (l it the valves are closed, as

The closure of the an of stack during re (ersal, that is,

a flow of gas for instance from the flue 14 through the valves G and G and the flue 19 directly to the stack. Further operation of the mechanism results in the raising of valves G, A and G, the valve A remaining closed. The return flow of the gas to the furnace has then started but it will be seen that while the gas valve to the stack is open so that the hot unburned gas in the checker chamber 10' can pass to the stack, the heated air in the checker chamber 11 cannot pass to the stack, so that there is no explosive mixture formed in the waste heat boiler. lontinued operation of the mechanism finally results in the raising of valve A as shown in diagram (Z after which the mechanism comes to rest, having effected a complete reversal. The interval of time between the raising of the valve G and valve A depends, as before explained, upon the angular relationship of the

cranks

32 and 33, the design of the connecting rods, and the speed of motor R.

Movement of the switch S will again effect a reversal to original position, the valves passing through the positions illustrated in diagrams e, and g, the diagram 9 being similar to diagram a.

Instead of utilizing the cranks and connecting rods illustrated in Figures 5, 6, 7 and 8 the valve operating levers may be operated by cams mounted upon the countershafts as shown in Figures 11 and 12. Figure 11 corresponds to Figure 8 and Figure 12 corresponds to Figure 7. The movements of the valves effected by the cams illustrated is exactly the same as in the first instance, the cams being so shaped that the valves are operated in the proper sequence.

Cams

60 and 61 correspond to

cranks

29 and 32 respectively and

cams

62 and 63 correspond to

cranks

33 and 34 respectively, each of these cams having a cam surface against which a roller mounted on the corresponding valve operating lever is adapted to bear, and to be held thereagainst by the weight of the valve suspended from the outer end of the lever. The cams are rotated in the direction indicated by the arrows and it will be seen that cam 62 is just beginning to open valve A. Valve A is fully open when the roller of the valve operating lever is resting on the peak of this cam and the shafts stop rotating with the cam in this position. The gas valve to the stack is opened by cam 61 considerably in advance of the opening of valve A and is held open, the corresponding roller passing over its circular peak port-ion while valve A is opening. During this movement valves A and G are not operated, but upon movement of cam 62 through a further angle valves A and G will be closed, and soon after, valves A and G opened.

While the arrangement of the cranks or cams in angular relationship to each other,

as explained, is generally sufi'icient to effect the movement of the valves at the desired times, additional means may be rovided to increase the length of the pause tween the opening of valve G and the opening of valve A This may be brought about, for instance, by the utilization of means for slowing down the motor temporarily. For instance, in Figure 14 is illustrated diagrammatically means whereby the resistance of the motor may be materially decreased when the countershaft has reached a predetermined angular position. The motor field 41 has connected in series therewith a resistance 7 0 controlled by rheostat arm 71 which in turn is operated by a cam 72 fixed on the countershaft 27. After the valve (1: has been opened the cam 72 becomes operative to move the rheostat arm 71 to the right against the action of the spring 73, and to thereby cut out the resistance 70, and cutting down the speed of the motor until the cam has allowed spring 7 3 to return arm 71 to original position, at which time the motor resllmcs its original s eed.

Other devices of t is character mi ht be employed if desired and in general, t e design and arrangement of the component parts of the invention may be atl moditied. the invention not being limit to the mechanism described herein and illustrated by way of example.

Having thus described the invention what I claim as new and desire to secure by Letters Patent is:

1. In apparatus of the class described, the combination of a plurality of valves to be opened in sequence, a motor, mechanism driven by the motor for o ening the valves sequentially, and means or retarding the speed of the motor during a redetermined period of the operation of said mechanism, whereby the lag between times of opening the valves may be increased.

2. A valve operating mechanism for regenerative furnaces including in combination, an electric motor operatively connected to the valve, a rotatable member driven by the motor and having actuating means thereon, and means adapted to be operated by said actuating means for temporarily reducing the motor speed.

3. 'A valve operating mechanism for regenerative furnaces including in combination, an electric motor operatively connected to the valve, a rotatable member driven by the motor and having actuating means thereon, and means for cutting out the resistance of the motor field operated b said actuating means for temporarily re ucing the motor speed.

4. A valve operating mechanism for re generative furnaces including in combination, an electric motor 0 eratively connected to the valve, 21 rotata le member driven by the motor and having actuating means thereon, and means adapted to be operated by said actuating means for temporarily reducing the motor speed, said means including a resistance element connected with the motor field circuit and a rheostat arm for varying said resistance.

5. A valve operating mechanism for regenerative furnaces including in combination, an electric motor operalively connected to the valve, a rotatable member driven by the motor and having actuating means thereon, and means adapted to be operated by said actuating means for temporarily reducing the motor speed, said means including a resistance connected in the motor field, and apivoted switch arm controlling the amount of such resistance in the motor field circuit, said pivoted arm operativcly engag ing and being actuated by said cam.

(i. A valve operating mechanism for re-- generative furnaces including, in combination, four valves, a crank arm corresponding to each valve, each crank arm being mounted on a rotatable member operatively connected to the motor, and means connecting each crank arm with the corresponding valve.

7. A valve operating mechanism for regenerative furnaces including in combination, four valves, a crank arm for each valve, and connected. thereto, two countershafts each countershaft supporting two crank arms, a motor, and means operatively connectiug the motor and conntershafts.

8. A valve operating mechanism for re" generative furnaces including, in combina tion, an electric motor, four valves, and means operatively connecting said motor and valves including four crank arms each rotatable about an axis, the angular relationship of the crank arms determining the order of movement of the valves.

9. In aregenerative furnace, the combination of air and gas regenerators for each end of the furnace, inlet and outlet valves for the regenerators, a drive shaft for operating the valves for each pair of associated regenerators, means for driving the drive shaft, and motion converting means between the drive shafts and the valves and arranged to produce cyclic operation of the latter wherein an air regenerat-or outlet valve is opened after its associated gas regenerator valve is opened.

10. In a regenerative furnace, the combination of air and gas regenerators for each end of the furnace, inlet and outlet valves for the regenerators, a rotary shaft for each pair of associated regenerators, means to secure synchronous rotation of the shafts, motion-transmitting means between the shafts and the valves for converting rotary motion of the shafts into rectilinear motion of the valves, said means being arranged for reversible cyclic operation of the valves of the reqcnerators and the air regenerator outlet valve being opened after the gas regenerator outlet valve in each cycle.

ll. In a regenerative furnace, the combinationof air and gas regenerators for each end of the furnace, inlet and outlet valves fo the regenerators, means for producing revc sible cyclic operation of the valves 'herein an air regenerator outlet valve is opened aftera gas regenerator outlet valve, said means including a rotary shaft for each pair of associated regenerators, means for driving the shafts synchronously, and means for converting rotary motion of the shafts into rectilinear motion of the valves, said motion-converting means for the air regenerator valves lagging in opening the latter 'ith respect to the motion-converting means for opening the associated regenerator outlet valves, and means for stopping the driving means upon a completion of a cycle of operation of said valves.

12. In a. regenerative furnace, the combination of air and gas regenerators for each end of the furnace, inlet and outlet valves for the regenerators, and means for produc ing reversible cyclic operation of said valves wherein an air regenerator valve is opened after a gas regenerator valve is opened in cluding shafts for each pair of associated regenerators, a motor for driving the shafts, motion translating means between the shafts and the valves, the motion translating means of the air regenerator valves lagging with respect to the motion translating means for the associated gas regenerator outlet valves, and means for rendering the motor ineffective upon a predetermined angular movement of one of the shafts wherein a cycle of operation of said valves is completed.

13. In a regenerative furnace, the combination of air and gas regenerators for each end of the furnace, inlet, and outlet valves for the regenerators, and means for producing reversible cyclic operation of said valves wherein an air regenerator outlet valve is opened after a gas regeneraitor outlet valve, said means including a shaft for each pair of associated regenerators, an electric motor for driving the shafts, motion translating means between the shafts and the valves for opening and closing the latter by rotary motion of said shafts, said motion translating means between the shafts and the air regen erator outlet valves lagging in effecting opening movement of the latter with respect to the motion translating means for opening the outlet valves of the associated gas regenerators, a movable contact member operated by one of the shafts and carrying a pair of overlapping contacts, a pair of cont acts adapted to engage with each of said overlapping contacts, and a switch for completing a circuit to said motor and a pair of contacts in engagement with one of the overlapping contacts.

14. In a regenerative furnace, the combination of air and gas regenerators for each end of the furnace, inlet and outlet valves for the regenerators, and means for producing cyclic operation of said valves wherein an air regenerator outlet valve is opened after its associated gas regenerator outlet valve is opened, said means including a shaft for each pair of associated regenerators, an electric motor for driving the shafts, motion translating means between the shafts and the valves for converting rotary motion of the shafts into rectilinear motion of the valves, said motion translating means for the air regenerator outlet valves lagging in operation with respect to the motion translating means for the associated gas regenerator outlet valves, a drum operated by one of the shafts, overlapping segmental contacts on the drum, a pair of contacts for engagement with eachof the segmental overlapping contacts, a switch for completing a circuit to said motor and a pair of contacts in engagement with one of said overlapping segmental contacts. and means for applying a braking effect to said motor when a segmental contact passes out of engagement with a pair of contacts upon the completion of a cycle of valve operation to stop the motor to stop the shafts and motion translating means with the other segmental contact in engagement with the other pair of contacts.

15. In a regenerative furnace, the combination of air and gas regenerators for each end of the furnace, inlet and outlet valves for the regeneratms, and means for produc-] ing cyclic operation of said valves wherein an air regenerator outlet valve is opened a after its associated gas regenerator outlett valve is opened, said means including a shaft for each pair of associated regenerators, an electric motor for driving the shafts, motion translatin means between the shafts and the valves for converting r0- tary motion of the shafts into rectilinear motion of the valves, said motion t-ranslab,

ing means for the air regenerator outlet 50 valves lagging in operation with respect to the motion translating means for the associated gas regenerator outlet valves, a drum operated by one of the shafts, overlapping a ing out of engagement with a pair of contacts, and means for opening said switch when said master switch is shifted to complete the motor circuit through the other overlapping segmental contact and its pair 7 of associated contacts.

In testimony whereof I hereunto a-fiix my signature.

CHARLES PRENTICE TURNER.