US2222502A - Draft control - Google Patents

Description

Nov. 19, 1940,

B. C. BERTRAM DRAFT common Original Filed NOV. 2, 1938 4 Sheets-Sheet 1 Ben [I Ber/ram By M u 19, 1940- B. c. BERTRAM DRAFT CONTROL Original Filed Nov. 2, 1938 4 Sheets-Sheet 2 6 a 4 22 J a 3 4 Z 1 a 5 e fi M I 0 M, ha a w /w A W B. w I B 5 z a 9 1 2 w 4 4E 8 2 NOV. 19, 1940. v Q BERTRAM 2,222,502

DRAFT CONTROL Original Filed Nov. 2, 1958 4 Sheets-Sheet 3 v 157% for: Barf (I Ear/ram ,5 M flzz 07 77630 Patented Nov. 19, 1940 UNITED STATES DRAFT CONTROL Bert 0. Bertram, Sayre, Pa.

Original application November 2, 1938, .Serial No. 238,490. Divided and this application May 1,

1940, Serial No. 332,672

14 Claims. (Ci. 110-150) This application is a division of my co-pending application, Serial No. 238,490, filed November 2,

This invention relates to draft appliance con- 6 trols and more particularly to controls for steam locomotive draft appliances and the like.

An object of the present invention is to automatically control and stabilize the back pressure of the exhaust steam that is effective in the draft appliance of a steam locomotive or the like to induce the draft for the fire.

An additional object is to automatically ,adjust the back pressure of the exhaust steam in a steam locomotive and thereby regulate draft caused thereby so as to so control the volume of air drawn through the fire as to assure proper combustion of the fuel in the fire box of the loco-- motive at all times during the operation of the latter.

It is to be noted, in this connection, that back pressure in a locomotive is the pressure efi'ective on the pistons of the locomotive and which is impressed thereon by the exhaust or spent steam from the cylinders and that such exhaust steam is customarily discharged through the smoke chamber and smoke stack of the locomotive so as to create an induced or artificial draft of air through the fire box, fiues and combustion chamber and thus effect combustion of the fuel in the fire box as well as of the fuel gases in the fire box, flues and combustion chamber.

It has been found, however, that the proper regulation of the back pressure in a locomotive and the resulting draft caused thereby, and the adjustment or accommodation of the back pressure and draft to the operating needs of the locomotive are, in actual practice, accompanied by a number of difllculties. Thus, for example, if the back pressure is too high it causes excessive draft and in so doing effects a waste of fuel in two ways, namely, first, by exerting an undesirable opposing force tothe action of the useful work performed by the live steam in operating the pistons in the cylinders, as well as the other working parts of the locomotive, and, second, by inducing too much draft through the fire box and flues of the locomotive, thus causing tearing of the fire, loss of fuel, cinder cutting, and other damage to the locomotive resulting from excessive"draft, especially such as may arise from drawing-unconsumed particles of fuel through the combustion chamber, smoke. chamber and stack, and the like.

On the other hand, if the back pressure of the exhaust steam is too low, and the consequent air draft through the fire box is too low to assure proper combustion of the fuel in the fire box of the locomotive, the result is likewise a waste of fuel which is frequently indicated by the discharge of heavy black smoke, representing un- 5 consumed carbon, from the smoke stack of the locomotive, and also such reduced quantity of air results in the production of carbon monoxide rather than carbon dioxide with a pronounced loss in heat value.

It will be seen, therefore, that it is distinctly important in a locomotive, to assure both efliciency and economy in fuel consumption, that the back pressure of the exhaust steam, and the draft induced thereby, be maintained at a minimum but yet high enough to furnish sufficient oxygen to assure complete combustion of the fuel in the fire box, and it is another object of the present invention to provide a new and improved device for accomplishing this result.

It should be noted, in this connection, that attempts have heretofore been made to employ both manually operated and automatically opcrating back pressure and draft appliance control devices in locomotives. However, none of such earlier manually operated devices, in so far as I am aware, has even been successful, because, among other reasons, manually operable back pressure and draft control devices are impractical in that such devices do not automatically, and therefore readily, respond to changes in back pressure of the exhaust steam.

Likewise, none of the earlier automatic back pressure and draft control devices has, in so far as I am aware, been successful because, among other reasons, such automatic devices have employed a single spring-urged controlyalve for automatically controlling the fiow of the exhaust steam from the cylinders to and through the exhaust passages to the smoke stack. 40

I have found, however, that single springurged valves cannot'be used for controlling the back pressure of the exhaust steam in its passage from the cylinders to and through the smoke stack because, among other reasons, such valves are responsive to and pulsate with the exhaust cycles of the locomotive, that is, unseat and close four times in each revolution of the driver wheels and, in so doing, wear themselves out in a comparatively very short length of time.

Hence, other objects of this invention are to overcome the foregoing and kindred difficulties which have been experienced in prior back pressure and draft appliance control devices; to associate pressure responsive means with controls of "the aforesaid character that are operative to adjust the induced draft to the air requirements in the fire box of the locomotive so as to assure proper fuel combustion both during ordinary operating conditions and extraordinary operating conditions as, for example, such as arise when the driver wheels of the locomotive slip on the rails which usually induces suchexcessive draft that tearing of the fire, cinder cutting, loss of fuel and the like take place; to prevent response of a pressure-operated locomotive draft appliance control to normal variations or pulsa-. tions in back pressure; to utilize a multiple valve responsive to the back pressure which wlll'nevertheless automatically function to stabilize the back pressure and the draft induced thereby and thereby sudden and violent increases or decreases in the back pressure are prevented; to insure the flow of sufllcient oxygen through the fire box of a locomotive to effect complete combustion during all operating conditions and thereby reduce the amount of smoke produced so that the view of the engine and train crews of the track and signals will not be impaired whereby safety of .train operation will be promoted; to employ a mechanically-operated valve and means associated therewith to stabilize the operation of a locomotive draft appliance; to prevent a mechanically-operated valve as aforesaid from ef- .fecting sharp or violent variations of the 1000- motive draft appliance; to enable a relatively high percentage of the grate area in a locomotive fire box to be devoted to air openings so as to facilitate the supply of air to the fire and inavoid the supplying of excessive air to the fire and thereby prevent tearing of the fire and kindred detrimentaleifects; and to enable a locomotive draft appliance control to be regulated 40, under control of the steam supply to the stokeroperating engine of a locomotive whereby the operation of the control will be automatically adjusted to the quantity of fuel being suppliedito the fire box. 45 Other objects and advantages will be apparent from the following description in which reference is made to the accompanying drawings wherein Fig. 1 is a fragmentary side elevational view of .9; modern locomotive showing a preferred form of the present invention applied thereto, and wherein a part of the wall of the smoke chamber is broken away so as better to illustrate the association of the present invention therewith;

Fig. 2 is a transverse vertical sectional view on line 2-2 in Fig. 1, through the smoke chamber of the locomotive, and showing the parts of the present invention which are associated therewith; Fig. 3 is an enlarged sectional view, on line 3-3 in Fig. 2, illustrating a typical and preferred form of automatic back pressure stabilizing and control valve which may be used in connection 7 with and as a part of the present invention; 65 Fig. 4 is an enlarged sectional view on line 4-4 in Fig. 1, illustrating a typical and preferred form of valve which may be used for the purpose of controlling the passage of steam from the steam supply line of the stoker-operating engine to the 7 0 cylinder of the main control valve which is shown in Fig. 3;

Fig. 5 is a transverse sectional view similar to Fig. 2, through the smoke chamber of a locomotive but illustrating a modified form of the pres- 75- ent invention associated therewith;

'sure proper combustion but at the same time to Fig. 6 is a fragmentary side elevation view illustrating the front end portion of a locomotive and showing the modification of the invention which is.shown in Fig. 5 associated therewith;

Fig. 7 -is a sectional detail view illustrating a typical form of mechanically operated control valve which may be used in,and is embodied in, the modified form of the invention which is illustrated in Figs. 5 and 6;

' Fig. 8 isan end elevational view of "a typical form of mechanically operated control valve which is illustrated in Fig. 7; and

Fig. 9 is a central vertical sectional view illustrating'a typical form of the back pressure stabilizing device which is embodied in the form of the invention which is illustrated in Figs. 5, 6,

A preferred and typical form of the present invention is illustrated in Figs. 1 to 4, inclusive, and is therein illustrated in conjunction with a modern type of locomotive which is illustrated, in part, in Fig. 1 and is therein generally indicated by I 0, only such parts of the locomotive being illustrated, and being referred to hereinafter, as are necessary for the purpose of explaining the construction and operation of the present invention.

The locomotive I0 includes the usual smoke chamber II, smoke stack I2, exhaust stand II in the smoke chamber below and aligned with the stack I2, such parts comprising in' the main, the draft appliance of thelocomotive which also includes the cylinders I3, grates I5, and stokeroperating engine which is generally indicatedat I6; the stoker-operating engine being of the steam-operated type and steam for operating the same being supplied thereto by means of a supply line or pipe I! under the control of means such as a manually operable valve II included in the supply line or pipe IT.

A by-pass 3 leads from the exhaust stand M to the inlet of a valve, generally'indicated by l9, which includes an outlet 60 from which an exhaust pipe 90 leads to the atmosphere. The valve I9 controls discharge of exhaust steam flowing from the exhaust stand I4 through the by-pass I8 to the atmosphere through the exhaust pipe 90'.

The valve I9 includes a valve casing 24 in which there is a plate 28 thatis disposedintermediate the inlet 25 and the outlet 60. The plate 28 has a plurality or row of openings therein into which the lower ends of the valve seats 29 are screw-threaded in such a way that the valve seats 29 project beyond the plate 28on the side thereof disposed away from the inlet 25. As best shown in Fig. 3, the valve seats 29 have domes that are disposed in spaced relation with the plate 28 and the domes 30 are of such nature that the portions of the valve seats 29 that project beyond the plate 28 are substantially bell-shaped. Similarly shaped valves 26 are provided which are disposed over the dome portions 30 of the valve seats 29 and which have parts that extend down over the portions of the sides of the valve seats 29 that project beyond the plate 28 to close the ports 3| provided in the valve seats 29. There is very slight clearance, as at C, between the sides of the valve seats 29 and the sides of the valves 30, and chambers D are defined between'the dome portions 30 of the valve seats and the complementary parts of the valves. In practice steam from the inlet 25 may leak through the clearances as 0 into the aforesaid chambers D to cause the valves 28 to be elevated and thereby disclose the ports 3|.

Stems 28' have corresponding ends thereof secured in the upwardly disposed portions of the 5 valves 28 and these stems extend through openings in a backing plate 38. Spring seats 38' are provided in the valves 28 about the stems 23', and other spring seats 3| are provided on the backing plate 38 about the stems 28', and springs 34 are disposed about the stems 28' and have opposite ends thereof arranged in the spring seats 38' and 3|.

A bar 38 is disposed between the backing plate 38 and the cover plate II that is secured to the valve casing 24 and at spaced intervals along this bar pairs of rollers 38 are provided, one roller of each pair riding on the underside of the cover plate 5| and the other roller of each pair engaging the backing plate 38.

Steam admitted into the valve casing 24 on one side of the plate 28 and leaking through a clearance C and into the chambers D must overcome theefiective pressure of the springs 34 prior to the time the valves 28 can be moved to disclose the ports 3|, the pairs of rollers 38 on the bar 38 backing up the plate 38 which, in turn, backs up the springs 34. When the pressure of the steam entering the valve casing 24 through the inlet 25 is of a predetermined amount, the valves- 28 disclose the ports 3| to permit the steam to flow through these ports from the inlet 25 to the outlet 88.

In addition to the valve seats 28 and valves 28, auxiliary valve seats 33, corresponding to the valve seats 29, are provided and valves 21 cooperate with the valve seats 33, the valves 21 being seated over the dome portions 35 of the valve seats 33 which correspond to the dome portions 38 of the valve seats 28. Stems 58, 40 corresponding to the stems 28', have corresponding ends thereof fast in the upper portions of the valves 21, and these stems extend through springs 48 which have corresponding ends thereof disposed in valve seats 48' on the valves 21,

the opposite ends of the springs being arranged in spring seats 52 provided on the underside of discs 48. The discs 48 are supported from the cover plate 5| and the stems 58 extend therethrough.

50 The auxiliary valve seats 33 and the valves 21 are provided to take care of surges in pressure of the steam admitted through the inlet 25 and also to afl'ord additional outlets in event the volume of steam flowing through the inlet 25 is greater than can be accommodated by the valves 28. In view of this it is preferable to arrange the springs 48 to have greater tension than the springs 34 so that higher pressure need be applied in the chambers D between the domes 35 andthe valves 21 in order to disclose the ports 28' in the valve seats 33. For example,

if the springs 34 are arranged to resist pressures applied in the chambers D up to five pounds, then the springs 48 may be arranged to resist pressures up to ten pounds in the chambers D' although it will be understood that the ratio between the eflective resistance of the springs 34 and 48 may be other than two-to-one as dictated by the circumstances under which the valve I8 is used.

It has been customary heretofore to so arrange the grates in the fire box of a locomotive that approximately not more than twenty-two percent of the grate is devoted to air openings for 75 it has been found that if a greater percentage of air openings is provided in the grateathen under those conditions where a high draft is induced by steam emitted, from the exhaust stand l4 the fire will be torn or otherwise detrimentally affected. It will be apparent, however,-

that if a larger percentage of air openings is provided in the grates of a locomotive, more oxygen will be admitted and this will be conducive to more efllcient combustion of the fuel. While the desirability of this condition has heretofore been appreciated, it has not been possible to attain this because it has been found that where, for example, the percentage of air openings in the grates was as high as forty percent the fire would be torn or otherwise detrimentally affected if the driving wheels of a locomotive should slip on the rails or if for other reason the quantity and pressure of the steam emitted'from the exhaust stand I3 was excessive.

However, in accordance with the practice of my invention I arrange the grate of the locomotive in such a way that air openings up to as much as forty percent or more of the grate may be provided and my invention operates to prevent tearing of the fire and the like, and this is accomplished in the following manner.

As stated heretofore, the springs 34 controlling the valves 28 in the control valve |8 are arranged to open when predetermined steam pressure is built up in the chambers D, and this adjustment of the springs 34 is such that under all normal operating conditions the valves 28 are open to disclose the ports 3| and permit steam to flow from the inlet 25 to the outlet 88 in such a way that the volume and pressure of steam emitted from the exhaust stand |4 into the stack 2 will not induce such a draft that the fire will be torn or otherwise detrimentally affected. On the other hand, the springs 34 are so adjusted that they will so control operation of the valves 28 that suflicient draft will be induced by steam emitted from the-exhaust stand H to insure proper combustion of fuel on the grates l5.

By way of example, if the percentage of air openings in the grate I5 is forty percent, the springs 34 may be advantageously adjusted to resist pressures up to five pounds in the chambers- D, but when pressure in the chambers D exceeds this amount it starts to open the valves 28 to disclose the ports 3| and the degree of opening of the valves 28 will be in direct proportion to the pressure in the chambers D so that if the pressures rise to say eight pounds substantial area of the ports 3| will be disclosed so as to permit rapid flow of steam to the outlet 88.

It will be noted that the by -pass l8 leads from the exhaust stand to the inlet 25 of the valve i8 and that the exhaust pipe 88 is connected to the outlet 88 of such valve |8 Preferably, though not necessarily, the exhaust pipe 88 discharges in front of the stack l2 of the locomotive so that any steam escaping through the exhaust pipe 88 will be caught in the blast being emitted from the stack l2 and carried upwardly so as to prevent this steam being thrown toward the cab of the locomotive. Thus whenever the volume of pressure of steam flowing from the exhaust stand i4 is greater than that which will insure proper combustion of the fuel on the grate IS, the valves 28 open to disclose the ports 3| and thereupon steam is by-passed from the exhaust stand M to escape through the exhaust pipe 88, and in this way the volume of steam emitted from the exhaust stand H to the stack i2 to induce the draft is so controlled that damage-to the fire on the grate I is avoided.

-It is recognized that there will be excessive surgesof steam toward the exhaust stand l4 5 and through the by-pass l3 as where the driving wheels-of the locomotive slip on the rail or where the locomotive is improperly operated in such a way as to supply excessive steam to the cylinders l3, and it is to care for such conditions that the auxiliary valves 21 are provided for when there is an excessive surge in pressure or an excessive quantity of steam emitted through the inlet 25 then the pressure ,will be such as to build up in'the chambers D in such a way as to overcome the effective resistance of the springs 43 and in this way the ports 23' will be disclosed.

As many valves 21 and consequently ports 23' will be provided as will be necessary to insure a that irrespective of the quantity'of steam adgo .mitted through the inlet 25 over and above that normally expected will be discharged through the exhaust pipe 90, and it will therefore be seen that the auxiliary valves 21 afford reserve escapes for the steam and serve tocare for abnormal con- 25 ditions. I

In locomotive operation there will be'occasions where it will be desirable to increase the firing rate as where the steam pressure falls below that required for the particular condition under which the locomotive is operating and in such instances fuel over and above that normally supplied to the grates I5 is supplied thereto. In stoker fired locomotives this is eflected byfurther opening of the control valve ll; thereby increasing the effective pressure of the steam admitted through the pipe H to the stoker engine so as to increase the operating speed of this engine and thereby supply additional fuel to the grates l5. In such instances and because additional fuel is being supplied it is desirable that the draft be increased which, of course, is to be effected by emitting additional steam from the exhaust stand l4 to the stack l2. With the apparatus as thus far described this would be prevented for the reason that both the valves 26 and 21 would open in such an instance and instead of additional steam being discharged from the stand M to the stack 2 the additional, steam would be discharged through the exhaust pipe 93. Thus in those instances where it is desirable that the induced draft be increased an arrangement is provided for increasing the efiective resistance of the, springs as 34, wherefore pressures in excess of that normally built up in the chambers D will be required in order to open the valves 26 so as to disclose the ports 3|. To this end cams 31 are provided on the backing plate 36 to lie in the path of the rollers 33 that normally engage the backing plate 36 and when it is desir- 0 able that the effective pressure of the springs 34 be increased, as in circumstances such as those just described, the rollers 38 are caused to ride up onto the cams 31 whereupon the backing plate 36 is forced toward the valves 26 which obviously increases the compression or the effective tension of the springs 34.

It has been explained heretofore that the rollers 38 are mounted on a bar 39. This bar 39 has an extension 43 projected outwardly of the valve casing 24 and the extension 40 is pivotally connected, as indicated at 46, to a rocker 45.

- The rocker 45 is pivotally connected, as indicated at 44, to a link 45' that is pivotally mounted, as

indicated at 46, on a lug 41' on the valve casing 24. A stem 43 is pivotally connected, asindicated at 44, to the rocker 45 and this stem is also connected to a piston 4| in-the cylinder '23, the cylinder 23 also being mounted on the valve casing 24. Whenever it is'desired to increase the tension of the springs 34, steamis admitted to the cylinder 23' whereupon the piston 4| is forced outwardly against the action of the spring 42, confined in the cylinder 23 and effective on the piston 4|, whereupon,'through the stem 43, the rocker 45 is moved so that the bar 39 is moved to thereby move the rollers 33 up onto the cams 31 It has been explained that it is desirable to increase the tension of the springs 34 in the manner just described whenever it is desired to combust a quantity of fuel over and above that normally consumed on the grate I5. It will, of course, be understood that manually operated means may be provided for supplying steam to the cylinder 23' to operate the piston 4| in the manner just described and in manually fired locomotives such an arrangement would be provided. However, it is desirable that the operation of my novel apparatus be rendered automatic as far as possible and hence in those locomotives equipped with a stoker-operating engine I6, to which a steam line I! is led to supply steam thereto to eiTect operation thereof, a steam line is led from the steam line I! to the inlet 54 of a pressure-responsivetvalve generally indicated by 2|. A steam line 22 leads from the outlet 55 of the valve 2| to the cylinder 23.

Thervalve 2|, which is shown in detail in Fig. 4, preferably includes a needle valve 59 which controls flow through the orifice 59' that is disposed between the inlet 54 and the outlet 55 of the valve 2|. A diaphragm 51 is associated with the needle valve 59 and has a diaphragm piston 56 associated therewith, a spring 53 being eflective on the diaphragm piston 56 to normally hold the needle valve 59 in position to close the orifice 59'. The spring 53 is enclosed in a housing 53 in which a spring adjusting nut 53 is provided so that the eflective'tension of the spring 53 may be varied.

It will be understood that the steam line 20 is connected to the steam line I! intermediate the control valve ll for the steam line I! and the stoker engine.|6. It will also be understood that the speed of operation of the stoker engine l6 and therefore the quantity of fuel supplied to the grate I5 is dependent upon the pressure of the steam admitted through the pipe I! to the engine I6. In view of this the spring 53 is so adjusted that so long as the effective pressure in the steam line I1 is not in excess of what will be called normal pressure, which is to say, pressure suflicient to so operate the engine l6 that a suflicient quantity of fuel will be supplied to the grate l5 to care for normal operating conditions of the engine, then 'the needle valve 59 remains seated to close off flow through'the orifice 59.

When, however, the steam pressure in the steam line I1 is increased above the aforesaid normal then such pressure is effective through the steam line 29 and inlet 54 on the diaphragm 51 whereupon the needle valve 59 is retracted from closing position with respect to the orifice 59' and hence steam will flow from the inlet 54 to the outlet 55 and thence to the cylinder 23 to effect operation ofthe piston 4| in the manner above described.

It will be manifest that pressure in the steam line I! will be reduced prior to the time all of that the rollers 38 remain in engagement with the cams 31 for a short time after pressure in the steam line H is reduced. This is accomplished by providing for the entrapment of steam effective on the diaphragm 51 and providing an escaping port 5'! in the outlet passage 55. Thus when steam has once unseated the needle valve 59, this needle valve remains unseated from the port 59"as steam slowly escapes from the port 51' and until the pressure exerted on the diaphragm 51 is in such a degree that the spring 58 will overcome this pressure and reseats the needle valve 59. An adjustment afforded by the screw plug 58' for the exhaust port 5'! enables this escape of steam to be so adjusted that the eflective steam pressure in the cylinder 23 is not reduced, so as to enable the spring 42 to dispose the bar 39 in the position in which it is shown in Fig. 3, until the excess quantity of fuel admitted to the grates l5 in the manner above described has been consumed so that in this way an automatic arrangement is provided for insuring proper combustion of the fuel even under those circumstances where an abnormal quantity of fuel is supplied to the grates l5.

In the use of my novel apparatus as thus far described the percentage of air openings in the grate is ascertained and the springs 34 are adjusted to hold the valves 26 closed so long as thepressure and volume of steam supplied to the exhaust stand l4 does not induce a draft in excess of that required for proper combustion of the fuel. When, however, steam pressure in the exhaust stand l4 and therefore in the by-pass l8 exceeds that which would induce a proper draft, it being understood that the degree of induced draft is in direct proportion to the pressure of steam emitted from the exhaust stand 14 toward the stack l2, then, first of all, the valves 26 open by reason of an increase in pressure in the chambers D as steam leaks through the clearances C thereinto. Under normal operating conditions only the valves 26 will be opened in those circumstances where the pressure of steam being emitted from the exhaust stand I4 is greater than that required to induce a proper draft, and such opening of the valves 26 causes the excess steam to flow through the by-pass 14, valve l9 and exhaust pipe 90 to be discharged to the atmosphere. What I have referred to hereinabove as the auxiliary valves 21 are, in reality, protection valves and these valves only function in those instances where abnormal conditions arise such as are induced by slippage of the driver wheels of the locomotive, and in such an instance there will be an abnormal rise in the back pressure of the steam and this will overcome the tension of the springs 43 and open the protection valves 21 whereupon additional outlets for the steam are afforded so that abnormal surges of steam are taken care of and abnormal increases in back pressure which might cause an abnormal increase in draft are avoided.

The valves 26 are opened, as explained, by building up pressure in the chambers D, and such valves once opened remain open until the steam accumulated in the chambers D escapes therefrom through the relatively small clearances C, and this is also true of the protection valves as 21 which are opened by building up pressure in the chambers D. It will be recognized that in normal locomotive operation the back .pres-- 76 sure pulsates by reason of the intermittent discharge of steam from the cylinders in each revolution of a driver wheel and therefore the back pressure rises and falls. The rapidity of such pulsations is, of course, directly proportionate to the'speed of operation of the driver wheels of the 5- locomotive, and preferablythe clearances C are such that under no circumstance can steam' so escape from the chambers D,'intermediate pulsations induced in the back pressure by reason of steam escape from the cylinders, that even when the driver wheels of a locomotive are turning over quite slowly, the valves at once opened remain open until themean of the back pressure falls below that which the springs 34 are set to overcome.

This arrangement is quite important for it eliminates pounding of the valves such as might result if the valves were directly responsive to steam \pressure for such valves would of necessity open and close with the pulsations of the steam escaping from the cylinders, and such operation of the valves would so. shorten the lives thereof as to render the device impractical. However, the steam collected in the chambers D of the valves of my invention has a cushioning effect which prevents such pounding of the valves.

It will be understood that other forms of cushion valves than those which I have described might be used and furthermore means other than steam-operated means might be used for causing 3 the valves to open at a higher pressure in a manner that is effected by operation of the bar 39 as described above. Furthermore, it is within the purview of my invention to employ a mechanically operated valve in place of the cushion valves, such as I have described above, but in order to prevent such a mechanically-operated valve opening and closing in response to pulsations in the back pressure caused by the intermittent escape of the steam from the cylinders, it is necessary to employ, in those instances where the mechanically-operated valve is employed, some means which will prevent the direct application of the back pressure on the means for operating the mechanical valves.

An arrangement employing a mechanicallyoperated valve of a kind suitable for use in the practice of my invention is illustrated in Figs. 5 to 9, inclusive, and by referring thereto it will be seen that a by-pass 8| leads through the smoke chamber 63 of a locomotive from the exhaust stand 62 to the inlet 69 of a valve 65, which includes an outlet 10 from which an exhaust pipe' 9| leads to the atmosphere in front of the stack 64 just as the exhaust pipe 90 leads to the atmosphere in front of the stack I2 in the form of my invention shown in Figs. 1 to 4.

The valve 65 includes a substantially cylindrical valve casing 68 in which a sleeve H is provided. A chamber 69" is provided in the valve casing 68 about the sleeve 'H and the inlet 69 leads to this chamber 69'. A plurality of ports 12 is provided in the sleeve II and these ports communicate with the chamber 69'.

A valve sleeve 13 is mounted in the sleeve H and has a plurality of ports 14 therein which, upon rotation of the valve sleeve 13, may be moved into and out of alignment with the ports 12. When the .ports I4 are aligned with the ports 12, communication is established between the chamber 69' and the interior of the valve sleeve 13 that leads to the outlet 10 of the valve 65.

In the present instance a gear 15 is fast to the valve sleeve 13 at the end thereof opposite the end communicating with the outlet in, and a pinion 18 fast on the shaft 11 meshes with the gear 15, the shaft 11 being mounted in the closure plate 15' fast to the valve casing 88. The

shaft 11 extends beyond the closure plate 15 and has an arm 18 fast thereto.

A cylinder 82 is provided in which a piston 8| is reciprocal against the effect of a spring 82. A stem 80 leads from the cylinder 82 and has one end thereof connected to the piston 8| and the opposite end of the stem 88 is pivotally connected, as indicated at 19, to the free end of the arm 18.

A pipe 83 leads from the by-pass 8| to the intake of a pressure stabilizer 88 that includes a casing 84 having a pad 88' in the intake passage thereof in which a stud 88 is fast to secure a plate 85 in position to close the intake passage. The plate 85 has a plurality of passages 88 therein and a yieldable plate 81 normally lies over the upper ends of these passages to close the same, a flat spring 88 acting on the yieldable plate 81 to hold it in such passage closing position. A chamber 84' is provided in the, casing 84 above the plate 85 and a pipe 81 leads from the chamber 84' to the cylinder 82 to admit steam from the chamber 84' into the cylinder 82 between the piston 8| and the head of such cylinder.

' In this form of my invention as in the previous form the exhaust stand 82 is arranged in the smoke chamber J83 below the stack 84 and is sized to permit the emission therefrom of steam toward the stack 84 in such a way as to induce the proper degree of draft under normal operating conditions to effect efficient combustion of the fuel on a grate as IS, the degree of induced draft being proportionate to the percentage of air openings in the grate so as to prevent tearing of the fire and other detrimental effects.

So long as the quantity of steam passing to the exhaust stand 82 is not greater than that which will induce the proper degree of draft, the valve sleeve 13 is so disposed that the ports 14 therein are out of alignment with the ports 12 in the 45 sleeve 1|. When, however, the steam pressure exceeds a predetermined degree, such steam pressure being referred to herein as the back pressure inasmuch as it is the pressure which resists the effective work on the pistons of the loco- .50 motive, it is effective through the passages 88 to unseat the plate 81 whereupon steam is admitted into the chamber 84' and so long as the chamberr84, pipe 81 and cylinder 82 are in communication with the pipe 83, the pressure in the cylinder 82 and chamber 84' is equal to the pressure in the pipe 83 and the by-pass 8|. However, as has been explained heretofore, the back pressure pulsates due to the intermittent exhaust of steam from thepylinders and thus each time the pressure in the pipe 83 falls below the pressure of steam entrapped in chamber 84, the spring 88 is efiective onthe plate 81 to seat this plate to close off the passages 88, and this operates to maintain substantially constant pressure in the cylinder 82.

However, when there is a drop in pressure in the pipe 83 and therefore the by-pass 8| and stand 82 other than that occasioned by pulsations in the back pressure, steam leaks from the chamber 84 through the vent 88', which vent affords a by-pass about the plate 85 and the passages 88 therein, an adjusting screw 81' being provided to afford adjustment in the degree of leakage from the chamber 84' past the plate 75 85. Steam leaking from the chamber 84' through the vent or by-pass 88' causes a reduction in-pressure in the chamber 84' with a consequent reduction in pressure in the cylinder 82. -Whenever the pressure of the steam in the cylinder 82 is sumcient to overcome the effect of the spring 82', the piston 8| is moved and this movement is transmitted through the stem 88 and arm 18 to the shaft 11 whereupon the pinion 18 is rotated which, of course, rotates the gear 15 and the sleeve 13. Such rotation of the valve sleeve "brings the ports 14 therein into registration with the ports 12 in the sleeve 1| and the degree of registration of the ports 14 with the ports 12 controls the degree of steam flow from the by-pass 8| to the exhaust pipe 8|, the greater the registration thegreater the steam flow. Thus in direct proportion to the degree of back pressure, the ports 14 and 12 are brought into alignment to aflord an escape to the atmosphere from the exhaust stand 82 through by-pass- 8|, valve 85 and exhaust pipe 8| to the atmosphere, and in this way steam which might act to induce excessive draft is discharged to the atmosphere.

Inasmuch as the steam which actuated the piston 8| and consequently the registration of the ports 14 with the ports 12 is admitted into the cylinder 82 from the chamber 84' and since the steam pressure in the chamber 84' is stabilized,

it is manifest that the piston 8| does not move' in response to pulsations in the back pressure such as are induced by the intermittent exhaust of steam from the cylinders. However, substantial changes in steam pressure in the exhaust stand 82 is effective either through the passages 88 or the by-pass 88' to effect variation of the steam pressure in the chamber 84 and consequently in the cylinder 82 wherefore movement of the piston 8| and the consequent registration or de-registration of the ports Hand 12 is effected in direct proportions to substantial variations in pressure in the exhaust stand 82.

The ultimate effect of both of the above described forms of my invention and equivalents thereof is to tend to stabilize the back pressure in such a way as to control the volume and pressure of the steam emitted from the exhaust stands as H and 82, and in this way the degree of draft induced in the fire box of a locomotive is maintained relatively constant.

In the form of my invention shown in Figs. 1 to 4 abnormal surges in the back pressure are compensated for by protection valves such as the valves 21, and in the form of my invention shown in Figs. 5 to 9 such abnormal surges are compensated for by substantially complete registration of the ports 14 and 12, it being understood that these ports are so sized that when they are in complete registration sufficient escape is aflforded for steam to care for the most excessive conditions that would be encountered in operation of the locomotive with which the device is associated.

It will be manifest from the foregoing description that my invention contemplates stabilizing the back pressure in a locomotive in such a way as to enable substantially the maximum'percentage of air openings to be afforded in a grate for, by reason of the control of the induced draft that is afforded by my invention, the likelihood of tearing the fire and other detrimental effects of the excessive induced draft openings in the grate which will be conducive to the most efllcient combustion of the fuel passed to the grate. It will be manifest that such eflicient combustion of the fuel will enable the attainment of marked fuel economies.

A further important advantage of my invention is that not only is eflicient combustion of the fuel effected but I make it possible to more efficiently utilize the work produced, which is to say, by reason of stabilization of the back pressure and preventing the back pressure from becoming excessive I make it unnecessary to overcome that degree of back pressure which would is of the locomotive, for it will be apparent that the greater the back pressure the more resistance.

there is to the effective work being done in the cylinders of the locomotive and by stabilizing the back pressure and preventing it from building up excessively I make it unnecessary to overcome ojectionable back pressure.

A very important aspect of my invention is that the means are provided for stabilizing the back pressure, such means being the restricted clearances C in the form of my invention shown in Figs. 1 to 4 and the parts providing the chamber 84', in the form of my invention shown in Figs. 5 to 9. These means, which operate in y response to variations or, better, increases in back pressure, ,e such that they are not responsive to th pulsations or intermittent increases and decreases in back pressure such as are induced by the intermittent exhaust from the cylinders of a locomotive. It is very important that any such pressure responsive means employed in the apparatus be such that it will not be responsive to such pulsations in back pressure for otherwise the apparatus will continually open and close which will result in pounding of 40 reciprocatory parts and rapid wear of the parts which move relative to one another, either of which conditions is obviously objectionable, for either and kindred conditions will so shorten the life of the apparatus that the other economies realized by use of a device such as that to which my invention pertains are overcome because of the frequent replacement necessitated where parts wear out rapidly.

Other and further advantages of my invention will be apparent to one skilled in the art and while I have illustrated and described selected embodiments of my invention, it is to be understood that these are capable and susceptible of variation and modification and I therefore do not wish to be limited to the precise details set forth but desire to avail myself of such changes and alterations .as fall within the purview of the following claims. I claim: y I n -1. In a device of the class described, the combination of a fire box, a grate in said fire box, said grate having more than twenty-two percent of the area thereof devoted to air openings but wherein not more than substantially forty percent of the area thereof is devoted to air openings, a draft appliance for inducing a draft in said fire box and including a steam exhaust passage terminating in a discharge nozzle, and a control for said draft appliance, said control including means providing an outlet to the atmosphere from said exhaust passage in advance of said discharge nozzle, valve means responsive to steam pressure in said exhaust passage for regulating the discharge of steam from 75 said passage through said outlet and which valve detrimentaliy interfere with emcient operation means is constructed and arranged to open when predetermined steam pressure is established in said passage, and means operable to delay the closing of said valve means upon decrease in the pressure in said passage and functioning, to cause the valve means to remain open after decrease in the pressure below said predetermined pressure for a period oftime proportionate to the degree of pressure above said predetermined pressure that has been effective to open said valve means.

2. In a device ofthe class described, the combination of a fire box, a grate in said fire box, said grate having more than twenty-two percent of the area'thereof devoted to air openings but wherein not-more than substantially forty percent of the area thereof is devoted to air openings, a draft appliance for inducing a draft in said fire box and including a steam exhaust passage terminating in a discharge nozzle, and a control for said draft appliance, said control including means providing an outlet to the atmosphere from said exhaust passage in advance of said discharge nozzle, valve means in said outlet and responsive to steam pressure in said exhaust passage for regulating the discharge of steam from said passage through said outlet and which valve means is constructed and arranged to open when a steam pressure above a predetermined steam pressure is established in said passage, and means included in said valve means and operable to delay the closing of said valve means upon decrease in the pressure in said passage and functioning to cause the valve means to remain open after decrease in the pressure below said predetermined pressure for a period of time proportionate to'the degree of pressure above said predetermined pressure that has been effective to open said valve means.

3. In a device of the class described, the combination of a fire box, a grate in said fire box, said grate having more than twenty-two percent of the area thereof devoted to air openings but wherein not more than substantially forty percent of the area thereof is devoted to air openings, a draft appliance for inducing a draft in said fire box and including a steam exhaust passage terminating in a discharge nozzle, and a control for said draft appliance, said control including means providing an outlet to the atmosphere from said exhaust passage in advance of said discharge nozzle, valve means in said outlet for regulating discharge of steam from said passage through said outlet, means responsive to steam pressure in said'exhaust passage for operating said valve means and which pressure responsive means is constructed and arranged to open said valve means when a steam pressure above a predetermined steam pressure is established in said passage, and means interposed between the-pressure responsive means and said exhaust passage and operable to delay the closing of said valve means upon decrease in the pressure in said passage and functioning to cause the-valve means to remain open after decrease in the pressure below said predetermined pressure for a period of time proportionate to the degree of pressure above said predetermined pressure that has been effective to open said valve means.

4. In a device of the class described, the combination of a fire box,--a grate in said fire box,

said grate having more than twenty-two percent of the area thereof devoted to air openings-but wherein not more than substantially forty percent of the area thereof is devoted to air openings, a draft appliance for inducing a draft in said fire box and including a steam exhaust passage terminating in a discharge nozzle, and a control for said draft appliance, said control including means providing an outlet to the atmosphere from said exhaust passage in advance of said discharge nozzle, valve means responsive to steam pressure in said exhaust passage for regulating the discharge of steam from said passage through said outlet and which valve means is constructed and arranged to open when a steam pressure above a predetermined steam pressure is established in said passage and which valve means includes means wherein steam from said passage is entrapped upon the opening of said valve means, and means for delaying the escape of entrapped steam to a predetermined rate independently of and upon decrease in the pressure whereby said valve means remains open after decrease in the pressure below said predetermined pressure for a period of time proportionate to the degree of pressure above said predetermined pressure that has been effective to open said valve means.

5. In a device of the class described, the combination of a fire box, a grate in said fire box, said grate having more than twenty-two percent of the area thereof devoted to air openings but wherein not more than substantially forty percent of the area thereof is devoted to air openings, a draft appliance for inducing a draft in said fire box and including'a steam exhaust passage terminating in a discharge nozzle, and a control for said draft appliance, said control including means providing an outlet to the atmosphere from said exhaust passage in advance of said discharge nozzle, valve means in said outlet and responsive to steam pressure in said exhaust passage for regulating the discharge of steam from said passage through said outlet and which valve means is constructed and arranged to open when a steam pressure above a predetermined steam pressure is established in said passage and which valve means includes means wherein steam from said passage is entrapped, and means including a restricted passage providing for the escape of entrapped steam at a predetermined rate independently of and upon decrease in the pressure whereby said valve means remains open after decrease in the pressure below said predetermined pressure for a period of time proportionate to the degree of pressure above said predetermined pressure that has been effective to open said valve means.

, 6. In a device of the class described, the combination of a fire box, a grate in said fire box, said grate having more than twenty-two percent of the area thereof devoted to air openings but wherein not more than substantially forty percent of the area thereof is devoted to air openings, a draft appliance for inducing a draft in said fire box and including a steam exhaust passage terminating in a discharge nozzle, and a control for said draft appliance, said control including means providing an outlet to the atmosphere from said exhaust passage in advance of said discharge nozzle, valve means in said outlet for regulating discharge of steam from said passage through said outlet, means responsive "to steam pressure in said exhaust passage for operating said valve means and which pressure -'''responsive means is constructed and arranged toopen said valve means when a steam pressure above a predetermined steam pressure is establishedqin said passage, and means interposed be passage is entrapped and including means for delaying the escape of entrapped steam therefrom to a predetermined rate independently of and upon decrease in the pressure whereby said valve means remains open after decrease in the pressure below said predetermined pressure for a period of time proportionate to the degree of pressure above said predetermined pressure that has been effective to open said valve means.

7. In a device of the class described, the com.- bination of a fire box, a grate in said fire box, said grate having more than twenty-two percent of the area thereof devoted to air openings but wherein not more than substantially forty percent of the area thereof is devoted to air openings, a draft appliance for inducing a. draft in said fire box and including a steam exhaust passage terminating in a discharge nozzle, and a control for said draft appliance, said control including means providing an outlet to the atmosphere from said exhaust passage in advance of said discharge nozzle, and valve means responsive to steam pressure in said exhaust passage for regulating the discharge of steam from said passage through said outlet and which valve means is constructed and arranged to open when predetermined steam pressure is established in said passage and to remain open after decrease of such pressure below said predetermined pressure for a period of time proportionate to the degree of pressure impressed thereon above said predetermined pressure.

-8. In a device of the class described, the combination of a fire box, a grate in said fire box, said grate having more than twenty-two percent of the area thereof devoted to air openings but wherein not more than substantially forty percent of the area thereof is devoted to air Openings, a draft appliance for inducing a draft in said fire box and including a steam exhaust passage terminating in a discharge nozzle, and a control for said draft appliance, said control including means providing an outlet to the atmosphere from said exhaust passage in advance of said discharge nozzle, and valve means in said outlet and including means constructed and arranged to open and permit discharge of steam through said outlet when predetermined steam pressure is established in said passage and to remain open after decrease of such pressure below said predetermined pressure for a period of time proportionate to the degree of pressure cluding means providing an outlet to the atmosphere from said exhaust passage in advance of said discharge nozzle, valve means in-said out: let for regulating discharge of steam from said passage through said outlet, and means responsive to steam pressure in said exhaust passage for operating said valve means and which pressure responsive means is constructed and arranged to open said valve means when predetermined steam pressure is established in said passage and to maintain said valve means open after decrease of such pressure below said predetermined pressure for a period of time proportionate to the degree of pressure impressed thereon above said predetermined pressure.

10. In a device of the class described, the combination of a fire box, a grate in said fire box, said grate having more than twenty-two percent of the area thereof devoted to air openings but wherein not more than substantially forty percent of the area thereof is devoted to air openings, a draft appliance for inducing a draft in said fire box and including a steam exhaust passage terminating in a discharge nozzle, and a control for said draft appliance, said control including means providing an outlet to the atmosphere from said exhaust passage in advance of said discharge nozzle, valve means for regulating the discharge of steam from said exhaust passage through said outlet, means for operating said valve means to effect discharge of steam from the exhaust passage through said outlet in a degree proportionate to the steam pressure in said exhaust passage, and'means for rendering the operating means unresponsive to such steam pressure variations as are induced in the exhaust passage as an incident to the intermittent admission thereto of steam from. the cylinders of the locomotive.

11. The improvement in locomotive draft appliance controls, where the appliance includes a steam exhaust passage terminating in a discharge nozzle and where the appliance induces a draft through a fire box to which fuel is supplied by a stoker operated by a manually-controlled steam-operated engine, which improvement consists in means providing an outlet to the atmosphere from said exhaust passage in advance of said discharge nozzle, valve means responsive to steam pressure in said exhaust passage for regulating the discharge of steam from said passage through said outlet and which valve means is constructed and arranged to open when predetermined steam pressure is established in said passage and to remain open after decrease of such pressure below said predetermined pressure for a period of time proportionate to the degree of pressure impressed thereon above said predetermined pressure, valve control means operative to prevent opening of said valve meansuntil a steam pressure greater than the aforesaid predetermined steam pressure is established in said exhaust passage, and means operable under the control of the aforesaid manual control, when said manual control is operated to cause said engine to operate the stoker at a predetermined fuel feed rate, to render said valve control means operative as aforesaid.

12. The improvement in locomotive draft appliance controls, where the appliance includes a steam exhaust passage terminating in a discharge nozzle and where the appliance induces a draft through a fire box to which fuel is supplied by a stoker operated by a manually-controlled steam-operated engine, which improvement consists in means providing an outlet tothe atmosphere from said exhaust passage in advance of said discharge nozzle, valve means in said outlet and including means constructed and arranged to open and permit discharge of steam through said outlet when predetermined steam pressure is established in said passage and to remain open before decrease of such pressure below said predetermined pressure for a period of time proportionate to the degree of pressure impressed thereon above said predetermined pressure, valve control means operative to prevent opening of said valve means until a steam pressure greater than the aforesaid predetermined steam pressure is established in said exhaust passage, and means operable under the control of the aforesaid manual control, when said manual control is operated to cause said engine to operate the stoker at a predetermined fuel feed rate, to render said valve control means operative as aforesaid.

13. The improvement in locomotive draft appliance controls, where the appliance includes a steam exhaust passage terminating in a discharge nozzle and where the appliance induces a draft through a fire box to which fuel is supplied by a stoker operated by a manually-controlled steam operated engine, which improvement consists in means providing an outlet to the atmosphere from said exhaust passage in advance of said discharge nozzle, valve means in said outlet for regulating discharge of steam from said passage through said outlet, means responsive to steam pressure in said, exhaust passage for operating said valve means and which pressure responsive means is constructed andaarranged to open said valve means when predetermined steam pressure is established in said passage and to maintain said valve means open after decrease of such pressure below said predetermined pressure for a period of time proportionate to the degree of pressure impressed thereon above said predetermined pressure, valve control means operative to prevent opening of said valve means until a steam pressure greater than the aforesaid predetermined steam pressure is established in said exhaust passage, and means operable under the control of the aforesaid manual control, when said manual control is operated to cause said engine to operate the stoker at a predetermined fuel feed rate, to render said valve control means operative as aforesaid.

14. The improvement in locomotive draft appliance controls, where the appliance includes a steam exhaust passage terminating in a discharge nozzle and where the appliance induces a draft through a fire box to which fuel is supplied by a stoker operated by a manually-controlled steamoperated engine, which improvement consists in means providing an outlet to the atmosphere from said exhaust passage in advance of said discharge nozzle, valve means including interengageable parts normally urged into engagement one with the other to close off flow of steam from said exhaust passage through said outlet until a predetermined steam pressure is built up in said exhaust passage, operating means for effecting separation of said interengageable parts to permit flow of steam from said exhaust passage through said outlet in a degree proportionate to the steam pressure in said exhaust passage, said operating means including a chamber into which steam from said exhaust passage may be admitted to build up pressure therein and thereby effect separation of, said interengageable parts, said operating means also including means affording a, restricted passage between said exhaust passage and said chamber and through which steam flows slowly from and to said exhaust passage to and from said chamber whereby said operating means is rendered unresponsive to such steam pressure variations as are indetermined pressure is built up in said exhaust passage, and means operable under the control of the aforesaid manual control, when said manual control is operated to cause said engine to operate the stoker at a predetermined fuel feed rate, to render said valve control means operative as aforesaid.

BERT C. BERTRAM.

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