US1500674A - Safety valve - Google Patents

Description

Jul 8; 1924. I

' P. G. DARLING SAFETY VALVE Filed July 2. 192] 4 Sheets-Sheet l w a1; Wm

v 2.5mm P. G. DARLING SAFETY VALVE Filed-July 2, 1921 4 sneai -sneet "2 jy s, 1924.

P. G. DARLING SAFETY VALVE 4 Sheets-Sheet 3 Filed Jlily -2.

Patented July 8, 1924}.

PHILIP G. DARLING, OF BRIDGEPORT, CONNECTICUT, ASSIGNOR TO MANNING, MAX- WELL '& MOORE, INC., OF NEW YORK, N. Y., A CORPORATION OF NEW JERSEY.

serum! vulva;

Application filed July 2,

To all whom'ttmay concern:

Be it known that I, PHILIP G. DARLING, a citizen of the United States of America, and resident of Bridgeport, in the county of 'Fairfield and State of Connecticut, have invented new and useful Improvements in Safety Valves, of which the following is a,

' specification.

This invention concerns steam safety valves and relates more particularly to that type of valve device wherein the operation of the main valve is controlled by a pilot valve of relatively small dimensions. v

The tendency of modern steam engineer- .15 ing practice is toward the production of larger and larger boiler units having high evaporative efiiciencies with extremely rapid, steam production, while the working pressures employed have correspondingly increased. Under these circumstances, the

provision of safety valve devices having dis- 7 charge capacities commensurate with the rate of steam production has become increasingly diflicult. In many instances recourse has been .had to the multiplication of valves in order to provide the desired discharge capacity, this however, being contrary to good boiler practicewhieh demands that the number of openings in vthe'boiler' shall be kept as low as... possible.

If vertical lift valves are employed on marine boilers, it is often necessary to remove the entire valve from the boiler when it is desired to regrind the valve seat on account of the limited head room above the boilers which makes it impossible to do such work while the valve is in position, thus greatly increasing the time necessary to perform this operation.

-When it is attempted to load a valve of large capacity, such for example as is'employed in locomotive or naval practice, by means of a spring, this spring must necessarily be extremely'heavy. Such a spring, however, does not respond quickly to small variations in pressure and it is difiicult under such circumstances to keep the blow down of the valve within the desired limits. which in certain cases are precisely describedby law,-'-

or to'adjust such limits when circumstances so demand. This difilculty, however, is much less apparent when the total load upon the valve is small and when a relatively light spring may be employed. Certain attempts,

therefore, have been made to 1921. Serial No. 482,047.

provide large capacity safety valves having a small or pi 0t valve for determining their operation, but in most instances such pilot valves have been arranged to constitute integral parts of the main valve structure, thus materially adding to the size, of manufacture of the latter, and being in many cases of such a character as would make it difiicult to keep them in working order. In some cases' the pilot valve is employed as a fluid motor for actuating a relief, valve which serves as the immediate means for controlling the main valve. In the design of such an arrangement, however, great care must be exercised in order that any failure or breakage of the parts ofv such pilot or relief valve or of the conduits connecting them with the main valve, shall not result in failure of the latter to function. Moreover, if the pilot valve be directly connected to the relief valve, or'other part to be operated, it is clear that the load imposed by the latter is added to that of the-pilot valve spring in opposing the lift of the pilot valve, thus in some instances at least, rendering the action of the latter uncertain, whereas substantial accuracy of operation is a prime requisite ina safety .valvedevice.

The principal object of the present invention is to so design a safety valve device as to furnish the desired capacity to enable it properly to meet the demands of a boiler of any size, while at the same time restricting the external dimensions of the valve cas-' ing and particularly the vertical height of the same whereby to permit of its use wherethe head room above the boiler is very limited. A further object is to so design such a valve device as to permit of the regrinding of the valve seat without removing the valve from position, even though the head room above the boiler be very small, A further object is to provide for controlling the main valve by the use of a pilot valve comprising a small capacity safety valve'of ordinary commercial form having a relative- 1y light, adjustable spring, and the ilsual adjustable blow down ring, thus permitting the blow down of the main valve to be kept within precisely defined limits, while at the same time. allowing'of adjustment of the complexity, and expense under full pressure.

It is also an object of the invention to make such pilot valve as an independent unit detachably connected to the mam valve casing and ,to ntilize'such pilot valve as a fluid motor whereby to actuate an adjustably loaded relief valve serving as the immediate means for controlling the main valve, the parts being so arranged as to .permit the pilot valve to lift from its seat to a predetermined extent before it encounters any opposition Subsidiary to this latter object is the design of the relief valve in such 'manner as to make unnecessary the employment of ,a heavy spring for retaining it against its seat, and the provision of means whereby said pilot and safety valves may be secured against surreptitious adjustment by unauthorized persons.

A further object of the invention is to so design the main andcontrolling devices that upon breakage of the latter, or of the connecting conduits employed, the main valve will blow automatically, thus giving notice of such breakage, while at the .same time avoidin any possibility that the main valve may fai to function at the proper time.

While the above objects may undoubtedly be attained in various ways, the arrangement disclosed in the accompanying drawings is illustrated. as exemplifying means well adapted for carrying the present invention into eflect. In such draw1ngs,

Fig. 1 is an elevation of the complete valve device looking intothe discharge end of the main valve casing;

Fig. 2 is a plan view of the device shown in Fig. 1;

Fig. 3 is a vertical cross section through the main valve casing and on the axis of the main valve; ,7

Fig. 4 ,is a vertical cross section to enlarged scale through the pilot valve and the associated parts, the section being taken on a plane parallel to the axis. of the main valve;

Fig. 5 is a view similar to Fig. 4 but illustrating a modified form of relief valve, certain of the parts being broken away; and I Fig. 6 is a fragmentary detail in section illustrating a modified form of the main valve and its seat. I

Referring particularly to Figs. 1 and 2, the main valve casin is indicated at 1, such casing being of en stantially T-shape in vertical section as indicated in Fig. 3. This casing comprises the vertical leg 2 and the horizontally extending member 3. The member 2 may be provided at its lower end with a radial flange 4 if desired. The member 2 is provided with a vertical passage 5,

the. lower end of this passage being internally screw threaded for engagement with the up er end of a ni ple or pipe 6 leadin from e boiler. The orizontal ortion3 o the casing provides a substantia y horizonfrom the relief valve spring.

ring 14.

tal bore 3 which adjacent to its end 7 is point of discharge. The opposite end of the member 3 is provided with an external flange 10 with which engages a cover plate 11 for closing the horizontal bore at that end. This cover member is removable but is normally secured in position bymeans of a plurality of bolts such as indicated at 12. Concentric with the bore 3 there is provided a flange 13 extending from the inner wall -.of the casing, such flan e being provided with internal screw threa s whichengage an externally threaded annular ring 14. This ring 14 constitutes the main valve seat, and

by arranging it as an inde endent element it may readily be formed 0 a non-corrosive material different from that of the casing, and when worn may easily be replaced. The ring 14 provides an opening 15 through which steam from the passage 5 may be discharged into the'portion 7 of the bore 3.

In the closed end of the bore 3, there isarranged a sleeve 16 of any suitable noncorrosive material, such for 7 example as bronze, forming a cylinder within which slides a piston member 17. This iston member has a portion 18 of reduced iame- 'ter, thus providing a shoulder 19 between the main portion of the piston and such reduced portion. The reduced portion 18 ;terminates in an element 20 engageable with theseat 14, the member 18 thus constituting the main valve for controlling the opening a 15. In accordance with the preferred arrangement, the element 20 of the valve member 18 is bevelled inwardly to coop'.'ate

with a similarly bevelled surface of the Pro ectmg centrally from the member 18 v is a guide stem 21 which slidably engages within a sleeve 22 supported in a spider 23, such spider comprising the le s 24 extending integrally from the innerwa l of. the casing member 3. The space between the inner surface-of the cover plate 11 and the piston 17 forms a chamber 25 into which steam may leak from the passage 5, the piston for this purpose being slightly loose in the cylinder 16. With this arrangement, the normal pressure within the chamber 25 is substantially that of the passage 5. An opening 26 leads outwardly from the chamber 25 through the flange 10, the outer portion of such opening being screw threaded for engagement with a pipe connection 27. Se- "cured in this pipe conriectionis one extremity of a ipe 28, the urpose of which will be describe at length eremafter.

Referring to Fig. 1, there is indicated "a bracket 29 preferably formed integrally-with the casing member 2 and extendin laterally therefrom. 'Ilhis bracket is provi ed with-a substantially horizontal upper surface 30 and is continued within the casing member 2 in the form of a projecting lug 31. Ex-

tending upwardly from the lower end .of

tends the internally screw threaded nipple 46. Connectedwith the nipple is a pipe 41 which extends throughan opening in the side wall of the discharge end 7 of the bore 3 terminatin within the latter asindicated at 42 (Fig. 3 The opening in the wall of the casing 3 for the reception of the pipe 41 may be provided with suitable packing as indicated at .43. Between the chambers 38 and 39 of the pilot valve casing is an annular valve-seat 44 with which cooperates a valve 45, this valve being of the poppet type and having guide fins 46 extending down into the chamber 38. The-valve 45 is also provided with a radial flange 46 which co- 0 crates with an adjustable blow down ring 47 such ring having screw threaded engagement with an annular flange 47 surrounding the valve seat. This ring may, if desired, be provided with a series of spaced notches as 48 with which may engage a looking pin or screw 48 for retaining the blow down ring in properly adjusted position.

Extending upwardly from the valve 45 is a valve stem 49 connected to the valve in any desired and known manner. This stem passes up through the upper end of the casing and through an externally screw threaded sleeve 50 whereby the upper end of said stem is guided. The sleeve 50 has a head 51 of square or hexagonal shape with whicha wrench or other suitable operating tool may be engaged and is provided with a lock nut 52 forretaining such sleeve in adjusted position. Secured to the stem 49 at a point immediately above the valve 45 is a collar member 53, such collar member having an upstanding boss preferably provided with a spherical outer surface with which engages a s herical socket formed in the lower side 0 a plate 54. Resting upon the plate 54 is a coiled spring 55 which surrounds the stem 49, the upper end of such spring bearing against a second plate 56 which engages the lower end of the adjusting sleeve 50. By turning the sleeve 50, the

- tension of the spring 55 may be adjusted.

If desired, a lever 57 may be provided for manual-1y lifting the valve 45 from'its seat,

such lever being of usual and well known construction. 7

Extending upwardly from the upper end of the casing 37 is a secondary casing 58.

- This casing may, if desired, be integral with the casing 37, but as herein illustrated, comprises an independent member having screw threaded engagement with the casing 37 as at 58* and locked thereto by means of bolts 59 or in other desired manner. The casing 58 is of generally cylindrical form-and one side of said casing is provided with an opening of substantial size normally closed by a 'door'60 hinged at 61 to the main portion of the casing. This door is provided with an apertured lug adjacent its free edge, such lug cooperating with a similar lug 60 projecting from the outer surface of the casing 58. The shackle of? pad-lock 110 may be passed through the apertures in the respective lugs thus serving to lock the door against opening by unauthorized persons. Rotation of the casing 58 relatively to the casing 37 by reason of the threaded .connection between the two would alter the operation of the valve device as will hereinafter be described and to prevent surreptitious turning of the casing 58, the heads of the bolts 59 may be provided with transverse openings through which may be passed a wire or cord 64, the ends of which may be securedtogether by a seal 65. I l

Casing 58 is provided with one or more openings such as 66 for the escape of steain from the interior thereof. At its upper end, the casing 58 is provided with a valve chamber 67, having annular valve seats 68, 69 at its upper and lower end, respectively. Cooperating with the valve seats 68, 69 are the heads 70, 71, respectively, of a vertically movable valve 7 2, such valve being provided with guide finsor other suitable means for properly guiding-it in its movement. Projecting downwardly from the lower head 71 and throu h the valveseat 69 is a valve stem 73, S valve stem being provided with a diametral open ended slot within which is received the looped upper end 74 of a rod 75 constituting an extension of the stem 73. Through the looped end of the rod 75 extends a rivet or pin 7 6, whereby such rod is pivotally connected to the stem 73. The rod 75 is axially aligned with the stem 49 of the pilot valve, the adjacentendsof such rod and stem normally being spaced apart as indicated at 7 8*. By rotating the casing 58 relatively to the casing 37 this space may be varied, thus altering the amount of movement of stem 49 necessary 'to bring it into contact with the lower end An annular rib 77 extends of stem 75. downwardly into .the casing '58 concentric with the stem 7 3, such rib serving to position the upper end of a. coil spring 78 which is desired. The valve annular extension or stem 109 extending arranged within the casing 58 and which surrounds the rod 75. The lower end of the spring 78 rests against a plate 79 provided in its lower surface with a spherical cavity 6 engaging a spherical surface provided upon .comprising the heads 70, 71 to opening,

under pressure, may be varied. The head 70 of the valve 72 is of somewhat greater area than the head 71 and thus when subject to pressure, the valve tends to open, this tendency, however, being normally counteracted by the spring 78. As the valve head 70 is but slightly larger than the head 71, the valve may be considered, however, as substantially balanced, and thus the spring 78 may be relatively light so that little force is required to open the valve. Leading from the chamber 67 is a passage 2 formed in an outstanding. and external y screw threaded nipple 85. The pipe 28 previously referred to, is secured to the nipple 85 by means of the coupling 86 or in other desired manner, permitting the disconnec- 30 tion of the parts.

In the arrangement illustrated in Fig. 5, the pilot valve casing is indicated at 37? and its spring at 55. The stem of the pilot valve, indicated at 49*, extends upwardly and into the casing 58 of the relief valve.

The latter casin is supported upon bracket arms 100, extending upwardly from a ring 101 suitably mounted-upon the top of the casing 37. The relief valve casing 58 has a valve chamber 67 provided at its upper and lower portions with annular valve seats 68, 69', respectivel With such seats cooperate the valve hea s 70, 71, respectively, of a valve member 7 2 which is Vertically slidable 5 within the casing 58". From the lateral wall of the casing 58 extends a threaded nipple 87 to which the end of the pipe 28 is connected by means of a coupling-86. .The valve stem 49" passes freely up through a central opening in the valve 72 and is screw threaded" at its upper extremity'as indicated at 102. Engaging such screw; threaded extremity is a nut 103 which bears upon the upper-surface of a plate 104. A

:coil spring 105 surrounds the upper portion ofthe stem 49 and bears against the plate 104, the lower end of such spring resting upon a plate 106. The latter plate is supported upon a boss 107 projectlngup from 6 the valve 72 above the valve head 7 0.

\ a point below the lower surface of the casing 58 a collar 108 is secured to the valvestem 49, such collar bein adjustable thereon if 72" is provided with an downwardly below the valve head 71 and in a position to be engaged by the collar 108 as the stem 49 of the pilot valve rises. If

the collar 108 be adjustably secured to the stem, it is evident that the amount of lift of the pilot valve stem 49".before such collar 108 strikes the member 109 may be varied atwill.

In the arrangement shown in Fig. 6, the main valve member 18, cooperates with a valve ring .14" having screw threaded engagement with the flange 13". The valve is provided with a guiding stem 21* cooperating with a sleeve 22 as in the arrangement previously described. In the arrangement shown in this figure, however, the end surface of the valve member 18 is substantially flat and cooperates with the radial surface 20 of the valve seat ring. While it is preferred'to einloybeveled coacting surfaces, the arrangement illustrated in this figure may be found desirable under certain conditions of use.

In the operation of the mechanism illustrated in Figs. 1 to 4, it being assumed that the pipe or nipple 6 is connected to a boiler, steam at full boiler pressure will be ad mitted to the chamber 5. ,Steam will also be admitted to the chamber 38 of the pilot valve, passing thereto through the channel 31. .Steam also'leaks by the piston 18 and into the chamber 25 and by reason of the fact that the area of the piston 17 is greater than the area of the v lve 18, the pressure in the chamber 25 serves to retain the valve 18 against its seat 14, thus preventing the escape of steam from the chamber 5 into the discharge end 7 of the bore 3. Steam pass- 1 the conduit 28 and builds up pressure in the chamber 67 of the relief valve 72. If the boiler pressure rises to a point suiiicient to overcome the tension of spring 55, the valve 45 will be raised from its seat, the steam which 'blows out between this valve and its seat passing intothe discharge chamber 39 and through the pipe 41 into the discharge end of the main valve casing and thence out through the discharge pipe 9. Such steam is thus prevented from escaping mto the room or space in which the safety valve mechanism is located. As the steam passes out below the flange 46 of the valve 45, the energy of the steam tends to lift such valve to its full open position and the effect of such escaping steam may be varied in Well known manner by means of the adjustable blow down ring 47. a

As the valve stem 49 rises with the valve 45,. its upper end comes into contact with the lower end of the stem 75 and upon further lifting of the valve 45, the valve 72 is unseated. Immediately upon unseating of the valve 72, the steam contained in chambe permitted t pass out through the open-.

ings 66 and 84 into the surrounding atmosphere without causing any substantial annoyance to persons located nearby. As soon as the pressure in chamber is relieved,

the boiler pressure, acting upon the valve 18 and upon the shoulder'19 serves to slide the piston 17 to the left as viewed in Fig. 3, thus opening the main valve t full extent and permitting steam to blow freely out through the valve seat 14. and through the discharge pipe 9. As the opening through the valve seat 14 is substantially unobstructed, steam may be discharged 7 therethrough in ver substantial amount, it

being found experimentall that with a valve of this character, having a seat opening of approximatelythree inches in diameter, as great a quantity of steam can be discharged as through four 4%" valvesof ordinary construction. As soon as the boiler pressure decreases to the desired amount, the spring 55 returns the valve 45 to its seat, such action being controlled as above pointed out bythe adjustment of the blow down ring 47. of the valve 45, the sprin 78 returns valve 72 to closed position an pressure builds up in the chamber 25 of the main valve casing, whereupon the piston 17 moves to the ri ht and closes the main valve. It is thus evident that by reason of the arrangement of parts above described, the blow down-of the main valve depends entirely upon that of the pilot valve 45, and as the latter valve may be of relatively small diameter, the spring 55 may be made very sensitive to variations in pressure and thus the blow down of the valve 45 may be adjusted with great nicety. By reason furthermore of the fact that the valve stem 49 is normally spaced a short distance 7 8 from the lower end of the stem 75, the valve 45 is permitted to rise to a slight extent from'its seat before encoun- V tering any opposition from the spring 78 and associated parts. -This permits of the regulation of the valve 45 solely by means of the spring 55, the additional force necessary to lift the valve 72 being provided by the kinetic energy of the steam escaping over the valve seat 44. By arranging the adj usting means for the springs 55 and 78 within thecasing 58, it is possible to adjust them with the least possible trouble while at the same time the casing provides means for enclosing such adj usting devices whereby tampering with the same by unauthorized persons may be prevented. This is especially desirable in those cases where it is required that the valve springs be set orinspeeted by authorized ofiicials who may, with the present arrangement, seal. the casing, afteradfprovidin Immediately upon closing justing the valves, by means of the wire and seal above described.

By arranging the main valve casin to discharge'in a horizontal direction an by the horizontally moving valve, it is possible to reduce the vertical height of the casing to a minimum, thus permitting the placing of the valve in locations where the head room above the boiler is very small. It is also evident that b removing the cover plate'll, the main va've, including the piston 17, may readily be removed from the casing, and as the valve seat is then exposed it may be reground or replaced without necessitating the removal of the valve casing from the boiler, even though the head room above the boiler be restricted. The pilot valve device as hereinbefore described is substantially like safety valves of ordinary commercial type and such a valve may be utilized for this purpose, it being merely necessary to provide suitable means for mounting the casing 58 thereon. It is also evident that by mounting the pilot valve and the relief valve in separate casings and connecting them to the main casing by means of pipes, they may readily be removed from the main valve cas ing for repairs or replacement, thus avoiding the "necessity of replacing the entire valve structure when one of its component parts is broken or injured. By forming the valve 72 in the manner above described, that is to say, with its upper head slightly larger than its lower head, it is clear that if its spring should be broken, the valvewould lift automatically, thus blowing the main valve and giving notice of such injury while at the same time insuring the apparatus against failure to operate by reason of such breakage. Breakage of the pilot valve spring 55 ,valve to blow. Except when blowing the main valve 18 is held against its seat 14 by full boiler ressure acting upon the end of piston 1 thus the valve is held much tighter and more firmly against its seat than is a valve of ordinary design wherein the force of theclosing spring is nearly balanced by the steam at working pressure acting against the under side of the valve.

The arrangement shown in Fig. 5 operates in substantially the same manner as that above described but fails to provide means for enclosing the spring 105 or for preventing surreptitious adjustment of the springs 105 and 55 by unauthorized persons. While this device may be desirable under certain circumstances, that illustrated in detail in Fig. 4 is preferred.

Having thus described the invention in a referred embodiment of the same to-- get er with the mode of operation thereof, what I claim and desire to secure by Letters Patent of the United States is: 1. A safety valve device comprisin a casing, a valve seat therein, a main va ve cooperable with said seat and normally held to the seat by fluid ressure, a fluid motor independent of sai casing, and means actuated by the fluid motor after a pre: determined interval ofoperation thereof for relieving the seating pressure on the main valve. 1 v

2. A safety valve device comprising a casing, a valve seat therein; a movable main valve coo erable with said seat and normally hel to its seat by fluid pressure, a spring loaded pilot valve independent of said casing, and means actuated by the pilot valveafter a predetermined movement of the latter for relieving the seating pressure on the main valve.

3. A safety valve device'comprising a casing having a vertical inlet passage and a horizontal discharge passage communicatin therewith, a horizontally movable main va ve, a seat therefor a pressure actuated piston normally holding the main valve against its seat, a fluid motor independent of said casing comprising .a movable element whose movement is initiated at a redet'ermined pressure, and means, actuate by said element after a predetermined interval of its movement for relieving the pressure upon the piston of the main valve to allow the latterto open.

4. A safety valve device comprising a casing having a substantially vertical inlet passage, a substantially horizontal discharge passage, a horizontally movable-main valve normally closing said discharge passage, a pressure actuated piston for moving said valve, a relief valve for relieving the pressure at one side of the piston, a pressure operated pilot valve havin a loaded valve member, and means actua Is by said loaded member after a predetermined movement of the same under pressure to open the relief valve. Q

5. A safety valve device comprising .a

' main valve casing, a second casing contain- 'valve caslngs being removable as ing a relief valve, and a casing contai a p1 ot poppet valve, said relief and p1 ot a unit from the main valve casing.

. 6. A safety valve device comprising a main valve casing having a .valve movably inounted.therein, a relief valve casin hav: mg therein a valve for determinin t e actuatlon of the main valve, and a pfiot valve casing having a poppet valve therein foregotuating the relief valve.

7. A safety valve device comprising a main valve casi having inlet'and dischar e'pasgem of sages, a re of valve casing indepen the main valve casing, a conduit connecting said casings, a pilot valve casing having a poppet-valve therein, and conduits connecting the latter casing with the inlet and discharge passages of the main valve-casing respectively.

8. A safety valve device comprising a main valve casing having inlet anddischarge passages, a main valve within said casing, an lndependent casing having a oppet valve therein, connecting passa es etween said poppet valve casing and t e inlet and discharge passage respectively of the main valve casing, and means actuable by thepoppet valve for controlling the movements of the main valve.

9. In combination with a pressure oper-" ated main valve, a fluid motor device for determining the actuation thereof, said motor device comprising a relief valveand a spring pressed poppetvalve, the latter being subjected to substantially the same pressure as that upon the main valve, and means for adjusting the blow down of said poppet valve.

10. -A safety valve device comprising a pressure actuated main valve, a relief valve for determining the actuation of said main valve, apilot poppet valve for controlling the relief valve, and means for determining the blow down of said pilot valve while the main valve is under pressure.

11. A safety valve device comprising a pressurecontrolled main valve, a relief valve for determinin actuation of the main valve, a pilot valve 0% the poppet type controlling the relief valve, said pilot valve having spring means normally operative to close the same, means admitting pressure to said pop-' pet valve, and means for adjusting the blow down of said latter valve while both valves are subjected to full pressure.

12. A safety valve device comprisin a pressure actuated main valve, a relief va ve for controlling the opening and closing of said mainvalve, a pilot valve determining actuation of the relief valve, said pilot valve being of the poppet type, a spring normally operative to close said ilot valve, and an adjustable blow down ring associated with said pilot valve for determining the blow down of said valve and thereby that of the main valve.

' 13. The combination with a pressure 210- z tuated main valve, of a device for controlling such a valve, said device com risin .a

casing having aspring pressed relief va ve thereln, a spring plressed poppet valve for controlling said re 'ef valve, and means for adjusting the tension of the springs of each of said valves.

14.,A valve device comprising an elongated casing having a valve seat adjacent one extremity, a valve en ageable therewith,

a s ring within the cas n for controll.i1ag sai valve, means within t e .casmg for a for said casing giving access to both of said adjusting means.

15. In combmation with a mam valve, a

relief valve for determining actuation of the main valve, :1. pilot valve for actuating the relief valve, springsfor urging each of said valves toward its seat, means for adjustably tensioning each of said springs, and a common casing enclosing said tension adjusting means.

16. A valve device comprising a substantially cylindrical casing, a valve seat adjacent; one end thereof a valve member, a spring normally operative to hold said valve member against its seat, means within said casing for adjusting the tension of said spring, and ahinged door forming a portion of the cylindrical wall of the casing and serving to give access to said adjusting means.

17. A safety valve device having a pressure operated main valve and means for controlling the operation thereof, said means comprising a casing having a pressure operated poppet valve therein, and a secondary casing removably secured to said poppet valve casing and having therein a rehef valve operable by movement hof the'poppet valve. l j 18. A valve controlling device comprising a relief valve, a pressure actuated valve for operating the same, springs for urging said valves towardtheir respective seats, means for adjusting the tension of said springs, a casing for enclosing said adjusting means, said casing having an openable closure, and means whereby said closure may be secured against surreptitious opening.

19. A valve device comprising a casing having a valve seat, a valve movable toward and from the same, a second valve casing having a poppet valve housed therein and a freelyopen outlet port for discharge of fluid passing the poppet valve, and mechanical means for transmitting movement of the poppet .y'alve to'saidifirst valve, the parts being so constructed and arranged'as to permit substantial movement of said poppet valve prior to movement of said first named valve.

20. A ,valve device comprising a casin having a valve seat, a valve movable towar and from the same, means normally holding said valve against its seat, a second valve casing having a poppet valve therein, said casing having a freely open outlet port for deliveryof fluid passing the poppet valve and mechanical means, for transmitting movement of the oppet valve to said first named valve to lift the latter from its seat, said mechanical means providing for lost motion between said valves.

21. A valve device comprising a valve seat and a valve normally engaging the same, said valve having a projecting stem, a valve casing housing a poppet valve; said casing having an open outlet port for the delivery of fluid passing thepoppet valve,

and a stem carried by the poppet valve, the U respective stems providing normally'spaced elements, constructed and arranged for operative contact upon a predetermined lift of said poppet valve.

22. A spring pressed valv ing a stem projecting therefrom, a valve casing housing a poppet valve, said casing having a freely open discharge port, the poppet valve having a stem ali ed with said first stem, the adjacent en s of said stems normally being spaced apart whereby said poppet valve is permitted to lift a substantial amount under excess pressure before being subjected to the load of said spring pressed valve.

23. A safety valve device" comprising a main valve casing, a main valve therein,

. I member havsov and a relief valve device for 'determining the actuationpf the main valve, said ,relief valve. device -comprisin a casing havin a pair of spaced, co-axiaFvalve seats, a va ve member having elements simultaneously engageable with said seats, a conduit leading from the space between said valve seats to the main valve casing, and a poppet valve having'an adjustableblow down for moving sald valve member whereby to disengage it from its seats.

Signed by me at Bridgeport, Conn., this 21st, day of June, 1921.

I PHILIP G. DARLING.

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