US1684897A - Low-water alarm - Google Patents

Description

Sept. 18, 1928. 1,684,897

H. B. THURSTON v LOW WATER ALARM Filed July 16, 1926 4 Sheets-Sheet '1 l gwuantoz Gm: new

Sept. 18, 1928. 1,684,897 I v H. B. THURSTON I LOW WATER ALARM Filed July 16. 1926 4 Sheets-Sheet 2 1 v 6 m 5 4* v Mil/)1 6? Sept. 18, 1928. 1,684,897

H. B. THURSTON LOW WATER ALARM Filed July 16. 1926- 4 Sheets-Sheet 4 Fat-t nted Sort. 18,

siren STATES HERMAN B. THUR-STON, or

CLEVELAND HEIGHTS, OHIO.

LOVJ-WATER ALARM.

Application filed July 16,

This inv. ition relates to a low water alarm for steam boilers and the particular adaptation is d gned for use with locomotive boilers. A very essential result, necessary to the success of low water alarms is that it shall sound when there is still water over the crown sheet or the boiler to enable the open ator to recoverthe normal water level, after the alarm has sounded, and before there is likelihood of any danger to the crown sheet from o .'erheating.

.lleretotore. v numerous attempts have been made to accomplish this result, but the requirements for successful operation on a railroad locomotive are very ditiicult to meet. t has been attempted to provide a time interval in the functioningof the alarm in order that it may not sound when only mon'ientarily subjected to low level of water.

in the previous applications of Herman 3. 'llh n 'ston, such for example, as Serial No. 26.711, filed July 18, l92l,-and Frank M. doby, 166,126, filed'March 19, 1925, it hasheen sought toaccomplish this by means of positioning a thermo-responsive alarm control within a certain zone, andcausing it to respond to an average water level irre spective of the surge of water and temporary displacement oi the level, bymeans of retarded thermal conductivity due to the alarm construction.

The present invention is designed on an en tirely diil'erent, and, I believe, novel principle, whereby the alarm is responsive Very accurately to a water level-the average being accomplished by such atime interval by the definite and positive timing of flowing water, determining an arbitrary level of the water controlling the alarm. It is well known that in stopping or even starting a locomotive, particularly on grades, that for brief intervals the water level is radically changed-the body of the water level surging to one end of the boiler. This has made very diflicult the causing of alarm to function with certainty, responsive to an average level of an 'inch or two inches over the crown sheet. At the time when the level of water is approaching the dangerous low level, the fall is quite rapid and further adds to the ditliculty of accomplishing the desired result. It has been demonstrated that with the present invention. the alarm maybe caused to sound only under actual conditions of danger, due to the tact that it is delayed say, titty seconds or one minute after the water is below the 1926. Serial 1e.- 122,916.

critical point at which the alarm functions. lhe alarm will not sound it the level is only temporarily dropped by surge of the water.

A further object ot' the invention is to so arrange such an alarm that it may be accessible for easy and convenient inspection, cleaning and replacement of parts. A still further object is to segregate a small portion of the water where its surging movement, due

to the movement oi? the locomotive, ispractically eliminated so that the actuating means for the alarm may be independent of any water surge effect. 7

Other objects and advantages include the construction of such a device, so that it will be simple and certain in operation of its moving parts, and also such that the pro+ vision of a means for conveniently testing the alarm may be provided. 7

Another outstanding advantage of the present low water alarm is that'atter the alarm is sounded and'the dangerous condition has been eliminated by the rise of the water level. the alarm automatically reconditions itself for further response without the attention of the operator. This is an import-ant feature when compared to arrangements, having a fusible metal controlling the alarm, in which cases, it is usually necessary to remove parts of the alarm in order to replace this metal. Therel ere, such former alarms would continue to sound as long as there is steam'in the boiler after it had oncebeen actuated. Other advantagesand novel,characteristics will be made apparentin the following description which relates to the drawings, illus trating a preferred emobdiment thereof. The essential novel characteristics are summarized in the appendedclaims. v

In the drawings, Fig. l is a cross-sectional diagram of a locomotive boiler, showing the position of this alarm device where usually mounted; Fig. 2 is an enlarged sectional detail of the outer sheet and crown sheet, carrying the alarm device, illustrating the relationship to the water level; Fig. 3 is a plan,

of the alarm; Fig. 4 is an enlarged transverse section through the same, on a planeindicated by the line 4; -4 of Fig. 3;Fig. 5 is a longitudinal section,tak en substantially on .a plane indicated by the line 5 -5 of Fig. 3; Fig. 6 1s a "section" taken longitudinally though the water tube of the alarm, as indicated bythe line 6-6 of Fig. 4 Fig. 7 is a sectional plan taken substantially on the line v-vor Fig. 4.

Fig. 8 is a sectiontaken on a plane indicated by the line El -8 of F 1g. 4; Fig. 9 is an enlarged longitudinal section of the alarm valve and operating means;

Fig. 10 is a sectional detail of the valve actuating means taken as indicated by the line '10-1O of Fig. 9.

ly to the chamber through thetube 6 having the inner extension 8., leading substantially to the top of the chamber and projecting inwardly, preferably at an angle, as shown, to a point near the crown sheet and below the water level, indicated at W. I prefer to cut the lower end of the tube at right angles to the tube rather than in the plane of the above the water in the reservoir whilethe bulk of the water in the reservoir will flow water level.

The shape of the reservoir is preferably that of a substantially flat cylinder, having an outer projecting cavity or chamber at 10 to accommodate and allow for the necessary movement of a float 12,; which operates the alarm whistle, indicated at15, aswill be presently described. The main body of the res ervoir provides for a predetermined capacity of waterwhich may be drained through a comparatively small opening near the lower part of the reservoir in the member 25. The downwardlyprojecting portion of the reservoir, as indicated at 11 is flanged with bracket members or ears 23 and is also pref: erably provided with a beveled surface 24 to provide a tight fit in the opening through the roof sheet. \Vithin this projection, I provide a securing means for the tube 6 in the nature of a member 25, held in threaded engagement. with the projection lland being threaded to receive the tube 6, projecting upwardly from below and the extension tube 8, threaded into the member from above.

A suitable cover may be provided for an opening in the upper portion of the reservoir, suitably secured as by screws and preferably provided with a threaded boss to re ceive the removableplug 32 over the end of the tube 8 to permit convenient inspection of the tube. Depending from the cover 30, I provide a downwardly opening yoke 31 in vwhich the float arm 42 may travel and be guided. 4 j j In line with the chamber portionltl, is a projection of the reservoir or casing, flanged to receive cover member 35, which in turn, is threaded to receive the nut 34.. On the innor side of the cover is preferably an into ral ear 39 as shown in Figs. 5 and 9, carrymg the pivot 40 for the float arm 42, which in turn, is loosely connected zit/l4 to a longitudinally movable valve stem 45, actuating to close the steam passage in the valve member 36. The bell crank portion of the float armpreferably fits over the ear 39 to assure a vertical swinging motion of the float arm.

In operation, assuming that the boiler is filled to a normal capacity of water, this level will be above thelower endsof the tube. As the steam pressure rises water will be forced upwardly through the tube 6,'to the reservoir 5, forcing the air slowly through the alarm until the float rises to close, the valve and thereafter, the level of water will rise in the chamber, the air and steam above the water being compressed by boiler pressure until the chamber will be substantially full, maintaining the float buoyant for holding the alarm valve closed. V 1 1 7 When the water fallsbelow the lower end of the tube 6, the tube 6 will drain quite quickly and steam passing upwardly through this tube will maintain the boiler pressure comparatively slowly 20 in the member 25. will drain in proportion to the size of the opening 20 and the water in the reservoir will through the opening start to lower while the water level in the boiler exposes the end of the tube for a predetermined tinie, say notless than a minute.

Then water in the reservoir will fall to. a

p unit where the float opens the valve by with drawing the valve stem 45, allowing the steam through the tubes 6 and 8, now free of Water.

to pass from theboiler to the chamber and then, e through the valve passages to the whistle,sounding the alarm. This flow of steam, sounding the alarm, will continue as long as the water level in the boiler remains below the end of the tube.

It will be seen, however, that if,'due to a temporary surge of water, the lower end of the tube is exposed, the water in the reservoir will start to drain but the alarm will not be sounded until the reservoir is emptied suiticiently to causethe float to fall and when the water returns again, covering the lower end of the tube, the boiler pressure will cause an upward flow again, substantially filling the reservoir asjin the first instance. will be seen that by this means, we introduce intothe positive operation of an alarm, the time elementby a predeteri'nined rate of flow of a certain amount of water, through a given orifice, to wit the opening 20. Thus thebot tom of the tube 6 must be exposed to steam for a predetermined lengthoftime or the equivalent to soundthe alarm. V

For purposes of testing the alarm at any therein outwardly,

The tube 6 therefore, I

ion

time, steam may be introducedinto the upper portion of the chamber througha pipe 60' valve 62.is closed except for test purposes. Upon opening the valve, the steam entering the top of the reservoir will release the hydrostatic head and permit the water to flow through the opening 20 until the float actuates the stem valve 45, causing the alarm to sound. Upon closing the hand valve 62, the reservoir again fills with water as previously described, raising the float and closing the alarm valve. It will be noted that the construction of the alarm valve is such as to accommodate very convenient inspection, repair or replacement. The float may be replaced or repaired by removal through the openings in the chambers. The tube 8 may be removed at any time through the opening closed by the cover 30. This givesaccess to the lower tubes to keep them free from boiler scale. The entire device may be very conveniently removed from the exterior. The arrangement of the tubes slanting inwardlyas shown, allows the device to be installed adjacent the steam dome if desired. and permits installation at a point'most convenient at the exterior of the modern locomotive.

I claim:

l. The combination of a boiler having a steam space and a water space, a low water alarm comprising "a reservoir and a signal,

means responsive to water level and inclependent of temperature disposed within the reservoir for controlling-the actuation of the signal, said reservoir being disposed exteriorly oi the boiler and above the water level thereof, means for filling the reservoir when the water level in the boiler rises above an established point and means for draining said reservoir at a given rate when the water level falls below said established point, whereby the alarm operates on successive occasions in response to a predeterminedcondition of low water.

a 2. A low water alarm comprising in combination a closed vessel adapted to be secured to the exterior of the root sheet of a locomotive boiler at a point above the normal water level of the boiler, a conduit extending from the top of the vessel through the roof sheet and into the boiler and terminating at a point of dangerous water level in the boiler,

a float disposed within the vessel, a valve controlling the alarm, said valve being actuated by said float and means for successively draining and filling the vessel to successively sound and silence the alarm.

3. The combination of a. boiler having a crown sheet and roof sheet, a reservoir secured to the roof sheet above the normal water level of the boiler, a conduit extending to a point above the crown sheet ofthe boiler at the level of dangerous low water and adapted to be sealed by water of higher level, said conduit leading to the reservoir so that the reservoir is maintained full of water when the conduit is sealed by the water in the boiler,

means for draining the reservoir when the conduit is unsealed, a float in said reservoir, a valve actuated by said float for sounding an alarm, whereby the alarm may be successively sounded at each occurrence of dangerous low water.

4. In a low water alarm, the combination of a boiler having a crown sheet and roof sheet, a closed vessel secured to the root sheet above the normal water level of the boiler, a conduit extending through the root sheet to a point above and adjacent the crown sheet, said conduit leading to the vessel so that the vessel isiilled with water when the conduit is sealed by. the water in the boiler and drained when the conduit is unsealed, a duet in said vessel, a valve actuated by said float :tor sounding-an alarm device whereby the alarm may be successively sounded whenever the vessel is drained.-

The combination of a boiler having a steam space and a water space, a low water alarm comprising a. reservoir and a signal, means responsive to water level regardless of temperature disposed within the reservoir for actuating the signal, said reservoir being disposed exteriorly ofthe boiler and above the normal water level thereof, means for tilling the reservoir from theboiler when the water level .in the boiler rises above an e tablished point and means for draining said reservoir at a given rate when the water level falls below and remains below the established point, whereby the said signal will be successively actuated in response to low water in the boiler after the level of the water in the reservoir falls below a given hei 'ht for av given time. i

6. In combination with boiler having a steam space and water space, a low water alarm, comprising a signal and a. reservoir and adapted to be mounted on the boiler and having one passageway to the interior of the boiler and another to the signal, said reservoir being positioned above the normal water level of the boiler, the first passageway terminating below the normal water level of the. boiler and means including a float as sociated with the reservoir to control the actuation of the signal dependent upon the water level in the reservoir but independent of the passageway.

"7. In combination,a boiler structure having a steam space and water space, a low water alarm, comprising a float controlled signal, a reservoir for water to actuate the float, said reservoir being mounted above the, normal water level of the boiler, a conduit having an opening terminating within the boiler at a point of dangerous low water level and opening into the reservoir at the top thereof, and having a draining opening within the reservoir, and means including a float associated with the reservoir responsive to predetermined amounts of water therein by which to control the signal, whereby the. size of the draining opening may determine the length of time required for the signal to respond after'the boiler water falls belowthe conduit boiler opening.

8. A method of operating a low water alarm for steam boilers, wherein a predetermined interval of time is obtained as the water in the boiler falls below the danger point, including filling a small reservoir which contains a float for operating the alarm, said reservoir being positioned above the low water level of the boiler by raising water by boiler pressure through a passage active or inactive.

terminating at a danger level in the boiler, draining the water in the reservoir at a predetermined ratewhen the water falls below the terminus of the passage and causing the amount of water in the reservoir to control the condition of the alarm by raising or low ering the float to render it successively either 9. In combination, a boiler having asteam space and disposed exteriorly of the boiler and above the water level of the boiler, a float in said reservoir, a valve actuated by saidfloatand controlling an opening in the reservoir, a

conduit leading from the top portion of the reservoir through the bottom of thelreservolr into the boiler and terminating near the dangerous water level therein, and being adapted to fill the reservoir wit-h water when its lower terminus is sealed,"an orifice in the conduit within the reservoir and in the lower portion thereof, the orifice being of such dimension that a given volume of water will pass through it in a'certain time, whereby the seal- 1 in or unsealing of the terminus of the con- *2 duit renders the alarm successively active or inactive.

' 10. Incombination, a boiler, a chamber disposed above the boiler, a conduit leading from the chamber to the interior of the boiler" and terminating below the normal water a water space, a closed reservoir level of the boiler, an alarm indicating member, and means mounted within the chamber and movable with reference thereto and adapted to be actuated by the rise and fall of water in the chamber for controlling the operation of said member.

11. In combination, a boiler, a chamber disposed above the, boiler, a conduit leading from the chamber to the interior of the boil-' er and terminating below the normal water level oftheboiler, an alarmindicating memher, means within the chamber and adapted V to be moved with reference to the chamber by the rise and fall of water in the chamber for controlling the operation of said'member, and

other means connected to the chamber and to a source of steam supply for enabling said flrstmentioned means to be actuated for operating said member under conditions sim ulating normaloperation thereof under low water conditions in said boiler.

12. The combination of a boiler, a chamber disposed at a hi mal water level of t e boiler, a float in the chamber, an alarm signal, there being a valve disposed betweenthe chamber and the signal, said float being arranged to closethe'valve when the float rises and to open the valve when the float drops, and a conduitleading from the chamber into the boilerto the low water level of the boiler. a

13. The combination of a boiler, a chamber disposed at a higher" level than the normal Water level of the boiler, a float in the chain HERMA B. THUnsToN;

her level thanthe nori

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