US2118311A

US2118311A - Alarm water column

Info

Publication number: US2118311A
Application number: US124676A
Authority: US
Inventors: Walter J Kinderman
Original assignee: Yarnall Waring Co
Current assignee: Yarnall Waring Co
Priority date: 1937-02-08
Filing date: 1937-02-08
Publication date: 1938-05-24
Anticipated expiration: 1955-05-24

Description

May 24, 1938.

w. JjKlNDl-:RMAN ALARM WATER COLUMNl 5 Sheets-Sheei l Filed Feb. 8, 1937 May 24, 1938- W. J. KINDERMAN 2,118,311

ALARM WATER COLUMN Filed Feb. 8, 1937 5 Sheets-Sheet 2 lill.. l

Itveur' yg W ,ff

May 24, 1938. w. .1. KlNDERMAN ALARM WATER COLUMN 5 sheets-sheet 5 Filed Feb. 8, 1937 May 24, 1938. W, J. KINDERMAN ALARM WATER COLUMN Filed Feb. 8, 1937 5 Sheets-Sheet 4 May 24,' 1938.

W. J. KINDERMAN ALARM WATER COLUMN Filed Feb. 8, 1937 5 Sheets-Sheet 5 Patented May 24, 1938 PATENT OFFICE ALARM WATER COLUMN Walter J. Kinderman, Philadelphia, Pa., assgnor to Yarnall-Waring Companys Philadelphia, Pa., a corporation of Pennsylvania Application February 8, 1937, Serial No. 124,676

11 Claims.

invention relates to alarm water columns which operate when the water level in a boiler or the likeris abnormally high or abnormally low.

A purpose o f the invention is to obtain greater sensitiveness in the operating mechanism. of a water column, so as to enable the operating mechanisrntcV function at higher pressures and on smaller changes in water level at any given pressure.

'A further purpose is to locate in the same line, the fulcrum of the operating lever and the weight suspension pivotstoward the ends of the lever.

A further purpose is to locate the center of the actuating pin, engaging the valve stem yoke of an alarm water column mechanism, in or very near` the line including the lever fulcrum and the weight suspension pivots, and closely adjacent the fulcrum.

A further purpose is to shorten the levers of an alarm water column to permit the use of colmnns of vsmaller diameter.

A further purpose is to space the levers of an alarmvwater column by lugs that curve convexly to the f ulcrum, so that the moments of lateral flitional engagements of the levers will approach zero.

A further purpose is to improve and simplify the T rod connection to the chains of an alarm waterV column.

Further purposes appear in the specification and in thev claims.

In the drawings one embodiment and a minor variation thereof are shown, by way of example, choosing the form illustrated mainly from the standpoints of satisfactory operation and convenient explanation of the principles involved. o

Figure 1 is a sectional side elevation of a desirable embodiment` of the alarm water column gllllgeA I p Vligure 2 is an enlarged front elevation of the operating mechanism showing the supporting capfin section and omitting the water column body and the gauge. Y

Figure 3 is an enlarged top plan view of the levers in position and showing the valve stem yoke in dot and dash.

. Figure 4 is a section of Figure 3 on the line 4wd thereof in the direction of the arrows.

Y Figure 5 is a detail top plan view of the valve step yoke, being a section upon the line 5--5 yof Figure 6 in the direction of the arrows.

, Figure 6 is a side elevation of the valve stem yoke of Figure 5.

-Figure Y is1fragmentary section of the end Figure 8 is a section of Figure 4 taken upon the line 8 -8 thereof and to indicate a low-friction feature.

Figure 9 corresponds to Figure 8 but in somewhat dilerent form.

Figures 10 and l1 are diagrammatic elevations of the structures of the prior art and of the invention respectively.

In the drawings like numerals refer to like parts.

Describing in illustration and not in limitation and referring to the drawings:

In steam boilers and similar devices, it is conventional practice to employ a water gauge to indicate the water level, and mechanism adjoining the gauge for operating an alarm such as a whistle in case thewater level reaches an abnormally high or abnormally low level. In such alarm water columns of the prior art, difficulty has been encountered through lack of sensitiveness which has resulted in limiting the use of such alarm water columns to low pressures, or rendering them less certain of operation at high pressures, and in rendering them insensitive to a small change in water level. The present invention seeks to increase the sensitiveness from both standpoints.

In prior devices, the weight suspension pivots at the ends of the levers have been located on a line (assuming any lever to be horizontal) usually considerably below the fulcrum, resulting in variant sensitiveness in different water column positions. In the present invention, sensitiveness has been increased and made uniform by bringing the weight suspension pivots and the fulcrum substantially into line.

In prior constructions, the pin engaging in the valve stem yoke has been placed ordinarily in the vertical center of the lever and opposite the center of the opening in which the knife edge for the lever fulcrum is placed. In accordance with the present invention, the actuating pin is placed so that its center is on or close to a line connecting the high and low weight supporting knife edges which line passes through or very close to the lever fulcrum knife edge. This permits loeating the actuating pin much closer to the lever fulcrum knife edge than in the prior art construction, and, by greatly decreasing the lever arm of the actuating pin, correspondingly greatly increases the mechanical advantages at which the weights act upon the actuating pin. This has caused increased sensitiveness in the present invention, and has permitted a shortening of the levers and. a use of smaller Water column casings at the same or higher pressures, with resulting great economy.

In prior water alarm columns, the circular boss on the lever around the opening receiving the knife edge fulcrum was employed for spacing the levers. A considerable part of the engaging surface of the boss was at a relatively great distance from the fulcrum, so that its friction acted on a relative long lever arm.` In the present invention, spacing lugs are located to curve convexly to the knife edge so that the frictional engaging surfaces of the levers are minimized.

By the cooperative use of the different features of the present inventiom the device has been found to operate well with test pressures up to 1500 pounds per square inch with every appear ance that it will be successful at much higher pressure. Formerly the corresponding mechanism was limited to about '700 pounds per square inch. The features of the present invention have also made' it possible to open the valve at a change in water level of about three-eighths of an inch at 35() pounds per square inch pressure, where the prior art device required a change in water level of one inch for opening at this pressure. At i500 pounds per square inch the valve in the alarm column of the present invention will open at a change in water level of about one inch. No figure is available for the prior art device at this pressure.

In the structure of Figures l to 8 the water column casing l presents flanged openings at H andY i2 that connect into a boiler or the like, not shown, and at points respectively above and below the waterlevel in the boiler, and presents flanged connections at i3 and lI4 to any suitable water gauge l5. Valves are indicated at I6 and )il for use with the gauge I5 and a usual drain 'connection is shown at i8.

The operating mechanism of the Water column is carried upon a cap IS which cap is bolted at 2G to position against suitable lugs 2l of the body.

Laterally spaced downward lugs 22 from the inner face of the cap are formed to support the opposite ends of the lever fulcrum 23 and the

levers

24 and 25 balance upon the knife edge 26 of the fulcrum 23.

The

levers

24 and 25, preferably opposite counterparts, present actuating

pins

21 and 28 into oppositely directed horizontal slots 29 and 3i) of a valve stem yoke 3l, the actuating pins 2l and 28 being near to and spaced from opposite sides of the knife edge 25, the middle of the center line between the pins suitably being in or very near the common pivotal axis of the levers.

This yoke 3l at its lower arms spans the fulcrum 23, and at 32, vertically above the knife edge, pivotally connects to the valve stem 33. The tapered end 34 of the needle valve at the upper end of the stem 33 controls the discharge and non-discharge of steam through an opening 35 to a high or low water alarm whistle 35, which may be any suitable steam Whistle.

The whistle 35 threads at 37 into the casing 33 of the valve mechanism, Which casing threads at 39 into a central opening through the cap i9.

' High and low weights 40 and 4i are suspended by the

levers

24 and 25, the actuating-pin ends of the

levers

24 and 25 supporting the low weight at low-weight suspension pivots 42 and the ends of the

levers

24 and 25 away from the actuating pins 2l and 28 supporting the lhigh weight` at liighwweight suspension pivots 43. Y

The'high weight-4) is suspended by chains 44 between the high-weight suspension pivots 43 Vand opposite sides of the high Weight 4U. These chains 44 pass downward through side perforations 45 of the high Weight, and adjustably support the weight 40 at pins 46 under the Weight.

The low weight 4| is carried by a T rod 41, the vertical portion of which adjustably axially threads the low weight atY 4B, with lock nuts at 49, passes upwardly through a, central perforation 55 of the high weight and from opposite ends of the T bar 5l is itself suspended by lowweight suspension chains 52 to the lowweight suspensionpivots 42.

To permit widerrelative adjustment of the high and low weights, the T bar 5l, which limits the high position of the high weight, is located preferably fairly close to the supporting levers, and a feature of the present invention is directed to a connection between the T bar ends and bottom links of the low-weight-suspension chains 52, for maintenance of the precisely uniform spacing of the chains from one another at their lower ends at a distance for minimum frictionand minimum change of moment at the supporting low-weight suspension pivots 42.

As illustrated in Figure 7, each end of the Tl bar is bored at 53, beveled at 54 and receives a pivot pin 55 through the bottom link of the suspension chain 52. The pivot pin 55 is located longitudinally so that the opposing bevel surfaces of the pin head and of the bar end at 54 prevent lateral play of the chain andpermit very close clearance between the end of the pin and the interior Wall of the water column casing I0. The

pivot pin 55 suitably is held to position by a key 56.-

A number of the features of the invention are directed to an increase in the delicacy and uni# formity of indications of the device even with quite 'widely different pressures.

As indicated in Figure 4 I locate the weight suspension pivots at 42 and 43 so that a line 51 joining their axes crosses the lever pivot 23 substantially at the knife edge 25 and also locate the actuating pins 2l and 28 close to the lever axis, suitably with their center lines'up to or above the line 57 joining the suspension pivotal axes.

The low-weightsuspension pivots 42 and the high-weight suspension pivots 43 each comprise knife edges 42 or 43 engaging the upper edges of the openings of hangers 52' or 44 which connect to the chains 52 or 44. f

To reduce to a minimum friction from axial play of the levers 24 and 25 I limit such movement by engagement surfaces that curve convexly to the lever fulcrum.

In Figures, 4, and 8 these surfaces are shown at 58 and 59 at the end of lug extensions 60 and 6I from opposite sides of each lever, the surfaces in each case convexly curving to the pivotal axis of the lever. In Figure 9 these surfaces are on

ball members

62, 53, and 64 rigidly fastened to the knife edge member 23 in suitable recesses thereof, by pins 65 and in such manner that the ball centers are at the lever fulcrum.

It Will be understood that in. this type of high and low alarm water column, the operation depends on changes inthe buoyancy forces upon the Weights when the water level in the column changes, each weight vbeing buoyed by a force equal to the weight of fluid that it is displacing, this fluid being steam or water or part Water and part steam.

VAssuming the water level to be located between the weights, the downward pull of the lowweight pension pivots 422 and 432 and the downwardisreduced by a buoying force equal vto the weight ofthe low weights volume` of hot water `andthe downward pull of the upper weight is-reduced by abuoying force equal to the weight of the high weightsvolume of steam. n

In normal position Athe leversrare at rest .in position to hold the needle valve closed, this being the position at which the low-weight suspension pivots 42 are in their high position andthe highweight suspension pivots 43 in their low positions, the totally submerged and upwardly buoyed low weight being over-balanced bythe high weight buoyed merely by steam.

If the water rises to the high weight 40, a further rise progressively increasingly buoys the high weight and thereby progressively reduces its downward pull until, when the water level is at some point vertically intermediate the high weights height, the downward pull of the high weight is over-balanced by that of the wholly submerged lower weight, the levers. shifting to their open-valve positions. The steam then operates the lwhistle until the water level has fallen sufficiently to let the low weight again overbalance the high weight to close the valve..

In similar way if the water progressivelyv falls below the top of the low weight, its pullupon the balance progressively increases until it overbalances the upper weight to operate the whistle as above described.

Diagrammatic Figures 10 and 11 are intended to bring out the relative advantages of structures of the prior art and of the present invention. These are not intended as showings of complete v structures.

Figure 10 is intended to represent commercial structure of the prior art such as has been and still is widely used, and Figure 11 is intended to represent theA structure of the invention, as already described. In both figures,v one weightsupporting lever only is shown, since these levers are opposite counterparts and the operation of either is that of the other, except that they are oppositely placed with respect to the `lever fulrum 23 for joint action on the valve stem yoke..

In the diagrams the high` and low weights 40 and 4l or 4I'll and 4l' are shown laterally offset from the lever pivot and suspended from and directly below the high-weight and low-weight suspension pivots 43 and 42 respectively in Figure 11 and 432 and 422 respectively in Figure 10. These weights however are intended to correspond actually in general to the high and low weights 40 and 4I of Figure 1, since :they are intended to be in practice directly beneath the lever fulcrum 23 and each supported by oppositely directed ends of two levers. f

.In the prior art structure of vligure 10, the lever 25 is of generally diamond-shaped contour and bored along its longitudinal axis at 66, 61, 6.8, and 69 respectively to pass the lever fulcrum 23', to receive the actuating pin 21', to make loose pin connection with the low weight 4| and loose pin connection with the high weight 40'. As intended to lbe typical of prior art structure, the lines 10 and 1I respectively from the pivotal axis 26 to the 'low-weight suspension axis 422 and to the center of the actuating pin 21 are intendednto make angles of, for example, 'l1/g" and 291/3 respectivelywith the longitudinal axial'line 12.

'Thepivotal axis at 26. of the lever islocated well above its longitudinal axial line *12, thathas been 'made the line of centersl of the .bores 66, 61, 6,8, and 269' and b oth the upward offsetting 13 of the pivotal axis at 26 with respect to the S11-S- offsetting 13 ofthe actuating pin 21' with respect tothe pivotal axis have been considered advantageous as together providing for an easy accommodation Y of the device to different operating conditions by merely selectively varying lthe normal valve-closed position of the lever, as deter.- mined by suitable selection of the position for valve closure. In this way suitable adjustment is made between the effective lengths of lever arms of the low and high weights and also of that of the valve mechanism operating at the actuating pin 21 and also of the valve-opening moment exerted at the normal valve-closed position by the levers own weight.

The normal valve-closed position of the lever can be selectively varied by having the low weight suspension pivot 422 in the valve-closed position selectively anywhere between some distance bef lo-w to some distance above a horizontal line 14 through the lever pivot axis at 26.

It will be seen that progressive shifting of the normal valve-closed position will make material progressive change in the moment armof the highweight 40 with but little change in the moment arm of the low weight 4I; will make material change in the moment arm of the lever itself, that is in the horizontal offsetting 15 of the levers own center of gravity from the lever axis 26' rand will make material change in the moment arm of the weight of the valve mechanism 33' applied at the actuating pin 21'.

Fo'r example in Figure 10, assuming the '7l/2 and 291/3 construction angles above, if the valve seat 16 were vertically shifted to shift the valveclosed position of the low weight suspension pivot from 'l1/2 below to 71/2 above the horizontal line 12, then the armv ratio of the low and high weights would shift from. cos 71/2`/cos 'l1/2 or 1 to cos 7V2/cos 221/2" or 1.07; theeffective moment of the actuating pin 21 would shift in the ratio .of cos 141/3" to cos 291/3 or 1.11 and the` moment of the levers own weight from zero to that corre.- sponding to a 15 deflection out of the horizontal, that is, from. zero to the product of the weight of the lever, into the vertical offsetting 13 (Figure 10) ofthe pivotal axis from the levers o-wn center of gravity into 0.259, the sine of 15.

As aresult, in the prior art structure of Figure 10, the low weight emergence line 11, which is the low-water level for theoretical valve bale ance, the line downwardly beyond which any further fall of the water level will, except for the retarding effect of friction, cause the lever to shift to its open. valve position, and the high-weight submergence line 18, which is the high water level for theoretical valve ,balance and the line upwardly beyond which any further rise of Water will, except for the retardation of friction, cause the lever to shift into its open valve position, have been readily shifted by shifting the initial closed-valve position of the lever, for example by small changes in the height of the valve seat 16. Thus the use .of a thicker washer 1e for example under the valve seat 'l'u would favor the low weight 4l ascom.- pared to the high weight 40 and thereby upwardly shift the low-weight emergence line 11 of theoretical valve balance and correspondingly downwardly shift the high-weight submergence line '18 of theoretical valve balance.

While the prior art structure has thus had great advantages that have deservedly resulted in its commercial success and wide use it lhas nevertheless inadequaciesthat have been pro so great as tol make the device even inoperative, Y

and a particular object of the present invention therefore has been to provide a device suited to use -With very high pressures, and at any pressures to be more sensitive than the devices of the prior art.

This has been accomplished by locating the fulcrum 2li of the lever and the axes of the low and high Weight suspension pivots 42 and 43 on a common line 80 (Figure 1l), by locating the actuating pin 21 very close to the lever axis 26 and preferably on the line 80, and by reducing friction by the use of knife edges at the low and high weight suspension pivots 42 and 43.

In both the structure of Figure 11 and that of Figure 10, when the lever 24 is in its normal Valve-closed position, with the water level intermediate the low and high water levels 'H and 18, the turning moments toward closure exerted by the high Weight 40 or 4D and by the stream pressure pressing the valve to its seat, overbalance the opening turning moments exerted by the low weight 4l or 4l and by the weight of the valve mechanism.

At e-ach of the low and high water levels 11 and I8 for valve balance, these moments are relatively equal and for both structures the fraction we of submergence of the low Weight 4l or 4| at the 10W Water level T! for valve balance could be expressed as a relation w2=R2/ (D10-TDS) and the fraction S' presented to steam by the

high weight

40 or 40 as a relation Si=R1/ (Bw-Ds). In these expressions Dw and DS are the weights per cubic feet respectively of water and of steam at the given operating conditions, and the maximum change in the downward pull of either weight is measured by (DW-DS) times the cubic feet volume V of the weight. R1 and R2 are factors depending upon the design and the steam conditions and, with the prior art structure, depending also upon the selected position of the levers for valve closure.

In both structures R1 and R2 change with change in the steam pressure within the watercolumn and with the Figure 10 prior art structure the degree and character of such changes atvery high pressures make the operation indefinite and unreliable and in fact make structure that is very satisfactory at loW and moderate pressures inoperative at very high pressures. The downward off-setting of the laterally offset actuating pin 21 in the prior art structure which at low pressures is to some degree advantageous, becomes at very high pressures in every Way disadvantageous and the same is true, though probably to lesser degree, with respect to the upward offsetting of the pivot axis 26 from the line 12 joining the axes of the suspension pivots 422 and 432.

The value of (DW-INV for a given size V of weights is about one third less at 1500 pounds per square inch pressure than at say 100 pounds per square inch pressure, while the upward clo-V sure force exerted by the steam pressure Vupon the valve for a given valve'port is fifteen times as great. The first factor, for a given size of Weights 4B and 4l', reduces the available actu-A ating force by one third, and the second factor for a given location of the actuating pinY 21 and given size of valve port 25', greatly increases the needed actuating force beyond that needed at moderate pressures, and thereby, for any given type of bearing greatly increases the friction.

For this reason the type of bearings at 42 and 43 satisfactory Vat low and moderate pressures become unsatisfactory at very high pressures because at such pressures the neededV actuating force has Vbeen increased by the greater importance of the steam reaction upon the needle Valve, While the Vavailable actuating force for a given Weight volume has been materially diminished by the fallin the value of (DW-Ds), so that for use at very high pressures the requisite volume V and therefore the weight to be supported by the lever needs to increase beyondV that quite adequate at low or moderate pressures.

The same orifice may be used for the entire pressure range. The device has been found to operate quite successfully on an orifice of only one-thirty second inch diameter. For the lower ranges, however, somewhat larger orifices become desirable because of danger of clogging and I have successfully tested these devices using orifices of one-sixteenth inch diameter for the range of 100 to 500 pounds pressure and three sixty-fourths inch diameter for the range from 500 to 800 pounds pressure.

In the structure of Figure 11, intended to be suited to any usual pressures, whether very high or low, the greater importance at high pressures of the steam reaction upon the needle valve and the falling away of the term DW-Ds are counteracted by replacing the pin bearings with knife edge bearings and the importance itself of the steam reaction upon the needle valve is lessened by bringing the actuating pin very close to the axis 26 of the lever.

In the prior art structure, the values of R1 and Rz are Very different for the selectively diierent angular positions of the lever at valve closure, and this variance of R with angularly different initial settings of the lever is avoided in the structure of Figure 11 by making the lever axis 26 and the Weight suspension axes Y42 and 43 on a common line 80. 'Ihe actuating pin 21 also is preferably on this line, since R is then quite independent of small variations in the initial settings of the lever.

The values of R1 and R2 for the structure of Figure 10 are in complex functional relations With the initial angular setting of the balance, which differently vary the moment arms of the weights and also the moment of the steam reac- Vtion from the closure pressure on the needle valve.

In the illustrated structure of Figure 11, however, with the lever pivot 26, the actuating pin 21 and the suspension pivots 42 and 43 on a common line 80, and the weights 40 and 4l of equal volume, the terms R1 and R2 are independent of the initial angular setting of the lever, are relatively equal and numerically equal to (W-PA) b/Va in which lil/a is the ratio of actuating pin moment arm b to either weight moment arm a, V is the volume of either weight in cubic feet, P is the pressure Within the alarm column in pounds per square inch, AV is the area of the valve port closed by the valve in square inches, and W is a weight in pounds'assumed in the formula to be applied at the actuating pin 21 and therefore having a moment arm b. In actual practice W includes the Weight of the valve mechanism at the actuating pin, with a moment arm b; and the other Weight corrected to a moment arm a, and suitably applied to the T bar 5I or'upon the low Weight suspension chain at a portion thereof above the Water, or, perhaps less desirably, it may be applied as an increase in the weight 4l frs 'fequalitylof volumes ofithe two weights, making vltrland!litri-no longer quite equal, the requisite total-weight' upon the levers being somewhat greater with a somewhat greater vfriction and therefore lower -sensitiveness With the foregoing assumptions, according to theoryz"v b(W-PA) always'less than unity, can be selected to give` any desired Avalue for we, assuming known :values-,ofV (Dw'efDs), so that for example if the .valuesof `W and Aare related to give wz a value iof" 0.5,at low pressure conditions of say 100 'ljpound and with orifice diameters as follows:-

l l Pounds pressure jsf from to 500 3/64" from 500 to 800 z"' from 800 to` 1500 In these tests the lower weight approximated three' inches in diameter and three inches in length, and the upper weight was similar in shape and nearly the same size, the weight diierence-appearing largely in the weights of their suspensions.

. alt, will' be understood that the Values of (lDw- -'Ds)y in practice change with concentration .of salts or other impurities in theboiling water, being normally relatively high just before each -blowoffof the boiler, so that the line 11, Figure 'l'lyfor valve balanca'will be lower as the concentration of dissolved solids increases. .Whiletheinvention finds its best embodiment in aldeviceusing a steam whistle as the alarm, it will be understood that it is also applicable to a device using some other type of alarm, thrown by movement of the member.`

In view of my invention and disclosure variations4 andmodifica'tions to meet individual whim or particular need will doubtless become evident toothers skilled in the art to obtain all or part of the benefits of my invention without copying f the structure shown and I therefore claim all such in so far as they fall within the reasonable spirit and scope of my invention.

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

l. In an alarm water column, high-water and low-water weights, operating levers fulcrumed at their middles, upwardly directed knife-edges pivotally suspending the weights from near the lever ends, an actuating pin on each lever adjacent the fulcrum and means for operating an alarm in response to motion of the actuating pins, the fulcrum of the levers being substantially on the line through the knife-edge suspensions of theweights.

2. In an alarm water column, high-water and low-water weights, actuating levers fulcrumed lat their middles, upwardly directed knife-edges pivotally suspending the weights from near the lever ends, an actuating pin on each lever adjacentv the 'fulcrum and means.. for operating an Y Valarm in response' to motion of the Vactuating pins, the fulcrum of the levers and the actuating pin of each lever being substantially on the line connecting the knife-edge suspensions of the particular lever.

3. In an alarm'water column, a pair of levers fulcruming at their middles on a knife edge,`liigh water and low-water weights, 'suspensions for the 'weights from Athe levers, spacing means for the levers having conveily curved surfaces close- 'ly adjacent the fulcrum for spacing the weights with minimum friction and means operatively connecting the levers with an alarm.

4. In an alarm water column, an operating lever having aknife-edge fulcrum at its middle, having a spacing lug above and immediately adjacent to the knife edge fulcrum on the side adjoining a cooperating lever, having knife-edge suspensions at the ends of the lever and having an actuating pin adjacent the knife-edge'fulcrum.

5. In an alarm water column, an voperating lever having a knife-edg'efulcrumv at its center, having a spacing lug above and immediately adjacent tothe knifeeedge fulcrum on the side adjoining a 'cooperating lever, having knife-edge suspensions at the ends of the lever and having an actuating pin adjacent the knife-edge fulcrum, theknife-edge fulcrum, actuating pin and knife-edge suspensions all being on the same line.

6. In an alarm water column, the combination of a pair of levers each having an opening near its center',` a common central knife-edge fulcrum for thelevers, the levers having spacing lugs extending toward one another above and adjacent to the fulcrum, actuating pinsv on the levers onrespectively opposite sides of the 'fulcrum, a valve actuating yoke operatively engaging the actuating pins between the levers and pivotal weight suspensions on the ends of the levers.

*'7. In an alarm water column, the combination of apair of levers' each having an opening near its centena common central 'knife-edge fulcrum for the levers, the levers having spacing lugs extending toward one another above and adjacent to the'fulcrum, actuating pinsv'on the levers on respectively opposite sides of 'the fulcrum, a valveactuatingyoke operativelyl 'engaging the actuating pins between the levers and pivotal weight suspensions on the ends of the levers, the central knife-edge fulcrum, actuating pin and weighty suspensions for each lever all being substantially on a line.

8. In low and high water alarm mechanism for use with a boiler or the like, a casing in communication at high and low portions thereof with the water and steam spaces respectively of the boiler, a stationary horizontal fulcrum within the casing at a high portion thereof, a pair of laterally spaced levers centrally mounted upon and turning on the fulcrum, horizontal upwardly directed knife-edge weight suspension pivots near the ends of the levers, a high-water weight below the fulcrum having at one side suspension from one of the weight suspension pivots of one lever and at the other side suspension from the opposite weight suspension pivot of the other lever, a low-water weight spaced below the high-water weight and having suspension from the remaining weight suspension pivots, one of each lever, a yoke vertically above the common pivot, having downwardly depending arms spanning the fulcrum and having oppositely directed horizontal slots therein, one in each arm, an actuating pin on each lever to the side thereof supporting the low-water weight and fitting one of the oppositely directed horizontal slots of the yoke and an alarm mechanism operated by the yoke, the weight suspension pivots being located with respect to one another and to the fulcrum so that the line cross-connecting the weight suspension pivots of each lever will pass substantially through the fulcrum.

9. In low and high water alarm mechanism for use with a boiler or the like, a casing in communication at high and low portions thereof with the water and steam spaces respectively of the boiler, a stationary horizontal fulcrurn within the casing at a high portion thereof, a pair of laterally spaced levers centrally mounted upon and turning on the fulcrum, horizontal upwardly directed knife-edge weight suspension pivots near the ends ofthe levers, a high-water weight below the fulcrum having at one side suspension from one of the weight suspension pivots of one lever and at the other side suspension from the opposite weight suspension pivot of the other lever, a low-water weight spaced below the high-water weight and having suspension from the remaining weight suspension pivots, one of each lever, a yoke vertically above the common pivot, having downwardly depending arms spanning the fulcrum and having oppositely directed horizontal slots therein, one in each arm, an actuating pin on each lever to the side thereof supporting the lov/water weight and tting one of the oppositely directed horizontal slots of the yoke and an alarm mechanism operated by the yoke, the weight suspension pivots and the actuating pins being located with respect to one another and to the fulcrum so that the line cross-connecting the weight suspension pivots of each lever will pass substantially through the fulcrum and the actuating pin center.

10. In low and high water alarm mechanism for use with a boiler or the like, a casing in communication at high and low portions thereof with the water and steam spaces respectively of the boiler, a stationary horizontal fulcrum -within the casing at a high portion thereof, a pair of laterally spaced leverscentrally mounted upon and'turning on the fulcrum, horizontal upwardly directed knife-edge weight suspension pivots near the ends of the levers, a high-water weight below the fulcrum having at one side suspension from one of the weight suspension pivots of one lever and at the other side suspension from the opposite weight suspension pivot of the other lever, a low-water weight spaced below the highwater weight and having suspension from the remaining weight suspension pivots, one of each lever, a yoke vertically above the common pivot, having downwardly depending arms spanning the fulcrum and having oppositely directed horizontal slots therein, one in each arm, an actuating pin on each lever to the side thereof supporting the low-water weight, close to the fulcrum and fitting one of the oppositely directed horizontal slots of the yoke and a steam whistle including a needle valve operated by the yoke, the weight suspension pivots and the actuating pins being located with respect to one another and to the fulcrum so'that the line cross-connecting the weightV suspension pivots of each lever will pass substantially through the ulcrum and the actuating pin center.

1l. In low and high water alarm mechanism for use with aY boiler or the like, a casing in communication at high and low portions thereof with the water and steam spaces respectively of the boiler, a stationary horizontal fulcrum within the casing at a high portion thereof, a pair of laterally spaced levers centrally mounted upon and turning on the fulcrum, horizontal weight suspension pivots near the ends of the levers, an axially perforated high-water weight below the fulcrum having at one side suspension from one of the weight suspension pivots of one lever and at the other side suspension from the opposite weight suspension pivot of the other lever, a low-water weight spaced below the high-water weight, a suspension for the low-water weight from the remaining weight suspension pivots including a T bar extending through the perforation in the high-water weight, the cross bar of the T bar being axially bored and bevelled at the ends and the bores receiving pins to secure the suspensions to the T bar, a yoke vertically above the common pivot, having downwardly depending arms spanning the fulcrum and having oppositely directed horizontal slots therein, one in each arm, an actuating pin on each lever to the side there; of supporting the low-water weight and tting one of the oppositely directed horizontal slots of the yoke and an alarm mechanism operated by the yoke, the weight suspension pivots being 1ocated with respect to one another and tothe fulcrum so that the line cross-connecting the weight suspension pivots of each lever will pass substantially through the fulcrum.

WALTER J. KINDERMAN.