US1779056A - Pressure-responsive device - Google Patents

Description

Ocnzl, 1930 H. Rim. 1,779,056

I PRESSURE RESPONSIVE DEVICE Filed Aug. 20. 1927 v which is immediate and certain in its action Patented Oct. 21, 1930 UNITED STATES PATE-Nrorrlcs PANY, INCORPORATED, OF NEW YORK, N. Y., A. CORPORATION OF NEW YORK PRESSURE-RESPONSIVE IIEVIOE appmation mea August 2o, 1927. serial no. 214,272.

This invention relates vto pressure responsive devices, and more particularly' to a safety pressure relievingdevice for a pressure medium transmission line.

The prima object of this invent-ion is to provide a sa ety pressurerelieving device and uniformly effective for automatically relieving excesspressure developed in a pressure medium transmission line,

In accordance with one embodiment, this invention vcontemplates a device emplo ing a hardened steel die cooperating with a filagilesoft metal diaphragm which upon the development of an excessive or abnormal pressure ruptures and permits a pressure lto develop on an enlarged ysurface of a spring pressed plunger sufficient to overcome the action o the spring, thereby accelerating the relieving of the pressure in the associate pressure line. Fatiguing of the diaphragm due to normal pressure conditions 1s minimized by limiting the movement thereof toward the plunger-to the point of its resting only lightly von a vreduced surface of the plunger to `maintain it injan undistorted,

level lane. The plunger and its spring are-v contained in a. housin which may bequickly and easily removed rom the line as a unit to allow the A,insertion of another diaphragm or disassembled with safety when adapting the device to another predetermined pres- Sure.'

sheath tele hone cables andan interconnecting hydrau c transmission line with one embo iment of this invention inserted therein; Fig. 2 is a vertical sectional view of the safet pressure relieving device embodying this invention; 5 y

Fig. 3 is a fra mentary View of Fig. 2 upon the diaphragm eing ruptured by an excess pressure; y

HARRIS RAYMOND TILL, 0F CIOERO, ILLINOIS, ASSIGNOR TO WESTERN ELECTRIC Fi 4 is a fragmentary section taken on A the line 4 4 of'Fig. 2,- and v Fig. 5 is a horizontal section taken on a reduced scale on the line 5-5 of Fig. 2.

Referring now to the drawing 1n detail wherein like "reference numerals indicate similar parts, particularly Fig. 1, a hydraulic compressor 10 is connected to a lead sheath extrusion hydraulic press 11 by a header, pipe or line 12, which discloses one application of the safety pressure relieving device. In the lead sheathing of telephone cablesv the ram (not shown) of the ress 11 is actuated by hydraulic pressure urnished by the compressor 10, such pressure may be six thousand pounds per square inch or more. For a more detailed illustration and description of a hydraulic press of the type referred to hereln reference may be had to Patent 1,583,814 to example, by the ram of the press 11 striking a solid stop, in which case the water pressure may rise to a dangerous point in a tenth of a second and it is therefore necessary in order to protect the various apparatus, to immediately relieve with kcertainty the pressure upon it reaching a redetermined point. Also, particularl in the application of the device to a hydrau ic press used to extrude molten lead to sheath telephone cables, in the case of an excess pressure being developed in the hydraulic line with a conse uent actuation of the pressure relievin devlee to relieve such pressure it is desirab e in order not to delay the operation of the press to be able to reset the device in a minimum of time. In the a plication of the safety pressure relieving evice as illustrated in the drawing, the device indicated generally by the numeral 13 is inserted in the transmission line 12.

Referring now in detail to Figs. 2 and 3 the device 13 comprises an internally shouldered `sleeve or housingl 14` having mounted along the'lo'wer ortion. of its bore an externally shouldere circular hardened steel die block 17. A collar 18 threaded into the bore of the housing 14 and engaging the lower surface of the die block 17 maintains an annular horizontal surface of the latter in en gagement with a corresponding surface provided in the housing 14 as indicated by the Y numeral 1 9, thus iixedly positioning the die block 17 in the housing. Having a.sliding lit within a central aperture 2O provided in the die block 17 is a hardened steel plunger 21 provided at its lower end witha reduced portion 24 positioned in a pressure receiving chamber 25 provided at' the lower end of the aperture 20. The extreme lower end of the aperture '2 0 is of a diameter corresponding to the diameterof the reduced portion 24 of the plunger 21,1 the wall of the aperture being inclined or flared upwardly and outwardly -fromits extreme lower end. The aperture 2O between its lower dared end and the chambery 25 is provided'with a -plurality of uniformly 'lspauced radially arranged offset passages 26, as clearly shown in Figs. 2 and 4. A lower annular surface 27 of the plunger 21 at the Vpoint where the reduced portion 24 thereof commences is under-cut or inclined downwardly to the peripheral edge of theplunger' to provide a pocket. The purpose of the offset passages26 and the pocket formed by the under-cut surface 27'of the plunger 21` will become apparent as this description progresses. Formed upon the upper endof the plunger 21 is a circular head 28, the under sur acevof which rests upon the top surface of the fixed die block 17, which thus determines the normal positionof the reduced lower endl of the plunger within the extreme lower end of the aperture 20. Threaded into the upper end of the housing 14 is 'a plug or cap 29 provided upon its lower surface with a reduced shouldered' portion 31. Having a" sliding lit within a central aperture ofthe cap 29 is a shouldered stem 32 provided at its lower end with an enlarged circular head portion 33 which rests upon the upper surace of the lunger head28, the head 28 en-v aging wit in an annular depression, 34 ormed in the lower surface of the portion 33. The head portion 33 ofthe stem 32 is Vprovided upon its upper .end surface with a reduced shouldered portion 35 corresponding to the portion 31 of the cap 29, Mounted be-f tween the shouldered portions 31 and 35 of the cap 29 and the head portion'33respecl tively, is a compression spring 36 of predetermined reaction which servesto normally maintain the4 lun er head 28 in contact with the upper en Vsur ace of the die block 17. A shoulder 38 formed upon the stem 32 a vredetermined distance below the lower sur ace ofthe cap 29 provides a stop for predeterminedly limiting the upward movement. of'

the-@plunger-21 upon actuation of the device as will be more'fully described hereinafter.

Threaded centrally' into the stem 32 vhich `vided with a de ressed ann extends for a slight distance above the upper surface of the cap 29 is a headed screw 39 which serves to lock the stem 32 to the cap 29, thereby retaining the sprin 36 under will be maintained under substantially it",

normal compression between the shouldered portions 31 and 35 of the cap and the head portion 33 of the stem 32, the upper surface of the cap first engaging the lower surface of the head of the screw v39 and thereafter by continuing tov unthread the cap, the cap,

the stem and the spring may be -removed from the housing as a unitf `Formed in the die block 17 at a point above `the pressure receiving chamber 25 disposed at thelower ,end of the aperture 20 are a plurality of vradially extending uniformly spaced apertures 40 (Figs. 2, 3 and 5) `which are aligned with similarly arranged a ertures 41 provided -in the housing. 14. tation'upon the housing 14 between an anounted for ronular shoulder 44 formed upon the periphery of the housing aritl a clampin collar 45 threaded onto thejlo er end of t e housing is a collar 46 provided u on its inner. e-

riphery with an annular c amber 47 which is aligned and at all times in communical tion with the'apertures 40 and 41 of the die block T17 and the housing.14, respectively. Threaded into the chamber 47 of the collar 46 is a pipe 48 which is disposed arallel to the axis of the device 13 at its disc arge end 49 and entered for free vertical movement in a pipe 50 which ma be connected to a drain for disposing o the .water passing through the pressure receiving chamber 25 when an excess pressure is developed in the line 12 in the application of the device 13 as illustrated.

Threaded into thea erture of the collar 18 at 'the lower end of t e casing 14 is a nigple 52, the lower end thereof being threa ed into the header or line 12 interconnect- .ing the compressor 10 and the press 11 (Fig.'

1). .The upper end of the nip le 52 is; proar machined surface 53 which ies parallel with the adjacerit lower end surface of thefdieblock 17,

which is also machined. Glam ed between the parallel sur-faces o f the die lock 17 and the nipple 52 is a fragile soft metal diaphragm 54 which serves to normall close vor seal the pressure-receiving cham r 25 from the line 12. The aperture throughthe` nipple 52 is preferably the same as the reduced portion 24 of the plunger 21 and the reduced portion of the aperture 2O into which the portion 24 extends during normal vpressure in the line 12. The lower end'surface of the portion 24 of the plunger 21 rests flush without pressure upon the diaphragm 54, thus forming a support for thev portion of the diaphragm 4extending across the inlet end of the pressure receiving chamber 25 and maintaining the diaphragm in a perfect plane Without any deleterious strain or distortion.

The operation of the safety pressure vrelieving device hereinbefore described is as follows: A spring 36 of a predetermined reaction Which is adapted to counter-balance the normal hydraulic pressure to be used to' operate the press 11 is selected and mounted in the housing as hereinbefore described along with a suitable diaphragm 54 to seall the die aperture 20. As long as the hydraulicl pressure contained in the line 12 is normal vor within the prescribed limits, the plunger 21 and diaphragm 54 will assume the Aposition as shown in Fig. 2. Immediately upon an abnormal pressure being developed in the line 12, due to any cause, the reaction' of the spring 36 will. be overcome due to the column of water, which acts as a punch, pressing upon the lower surface of the diaphragm 54, the upper surface of the diaphragm'lying flush against the under-surface of the reduced portion 24 of the plunger which is entered in the restricted fiared entrance port to the pressure receiving chamber 25, as hereinbefore described. -This pressure it will be a parentV will instantaneously deform the so metal diaphragm 54 to such-an extent that a complete rupture or shearing thereof willoccur, as clearly shown in Fig. 3, thus unsealing the restricted entrance port tothe pressure receiving chamber 25 whereupon the sudden release of the compressed column of water through the entrance port and the offset as- 1s directed upon the under-cut annular surface 27 of the plunger 21.A It will be readilyfunderstood that due to the flared wall of the' entrance port to the chamber 25 it is not necessary for the plunger 24 to move very far` before the diaphragm is ruptured to freely admit the water to the chamber. The movement of the plunger 21 upwardly is thereby accelerated to open the pressurev receiving chamber25 to the radial apertures 40 in the die vblock 17, the plunger coming to a rest when the'shoulder 38 of`the^stem 32 engages the lower surface of the/cap 29, as clearly shown in Fig. 3. -The inclining or under# cutting of ,the annular surface 27, as shown inthe drawing, it will be apparentserves to direct and-concentrate the pressure of the wate'ripon the plunger, thereby serving in addition to accelerating the movement thereof to the position shown in Fig. 3, to hold it in this position until the pressure is relieved. In this latter position of the parts it will be apparent that the water will freely escape from the chamber 25 to the apertures 40, into the annular channel 41 and thence into the chamber 47 of the collar 46, through the pipes 48 and 50 where it is directed to the drain or other suitable receiving means. Thus all possible damageto the compressor 10, press 'll and line .12 lupon the pressure rising to` an abnormal predetermined pointlikely to cause v damage is entirely eliminated.

lar 45, which it will be apparent will `permit, v

the housing 14 to be rotated within the collar 46. thereafter removing .the device as a whole from the u )per threaded end of the nipple 52.,

thus providing access to the ruptured dia' phragm 54.' Upon release of the excess pres- Y sure in the line 12, the spring 36 itwill be apparent will move the plunger 21 back to its normal position and with itthe sheared ldisk of the diaphragm 54.l Thus upon removal of the device 13 from t'he nipple 52, as just described, thev sheared diaphragm 54 may be readily removed from the depressed surface 53 of the nipple 52 and replaced with another. Thereafter the vdevice is threaded onto the upper end of the nipple 52, the discharge end 49 of the pipe 48 being entered in the pipe50 at thistime, until the dia' i phragm 54is clamped ti ght between the lower surface of the die block 17 land the portion 24 of the plunger 21 upon one side and the surface 53 of the nipple upon its opposite side. The clamping collar 45 is then threaded up tight to secure thechambered collar 46l agaipt the annular shoulder 44 of the hous- 1ng r Although this invention has been disclosed vand described as applied to a particular apv paratus wherein water is preferably used as the pressure medium, it is clear that it may have a more general application and is not necessarily limited to the relieving of excess hydraulic pressure, but is equally adapted to function regardless of the type of the particular pressure medium being used. Also. it

is clear that modifications canbemade inthev device without departing from the spirit and scope of the appended claims.v

What is claimed is 1. In a safety pressure relieving device.V` a housing having a step ed aperture, a plunger mounted therein havmg a plurality ofv surfaces of different areas each adapted to 'close astep of the aperture and to be actedupon byaspressure medium, means for limiting the forward movement of the plunger, and a fragile means normally closing the aperture and bearing against the surface of the plunger having the smaller area', responsive-to a pref determined pressure for communicating the pressure to the surface of larger area whereby movement of the plunger is accelerated and an exit for the pressure medium is established.

2. In a safetypressure relieving device, a housing having an inlet and an outlet port, an apert-ured member supported in the housing having a plurality ofpassageways extending,` laterally from the walls of the aperture thereof to the outlet port, a plunger mounted in the aperture having a plurality of surfaces of dilferentareas adapted to be acted upon by a pressure medium and normally positioned to completely close the passageways and the aperture, a surface of the plunger havinvr a smaller area being entered within and ush with a restricted inlet mouth of 75 my name this 10th day of August, A. D. 1927.

HARRIS RAYMOND TILL.

the aperture, means for limiting the forward lmovement of the plunger, an elastic medium operatively associated with the plunger for normally urging the same in one direction under a predetermined pressure, and a fragile diaphragm exposed upon one side to the pressure medium with its opposite side bearing lightly against the surface of smaller area, a surface of larger area than the latter surface forming one end of a chamber formed along' the aperture and against which the pressure medium is directed upon rupture of the diaphragm in response to a predetermined pressure whereby movement of the plunger ,is accelerated and anl exit for the pressure medium is established` between the inlet and outlet ports of the housing.

3. In a safety lpressure relieving device, a housing having an aperture, a plunger mounted thereinV having a plurality vof surfaces of different areas each adaptedto close the apertureand to be acted upon by a pressure medium, one of the surfaces being annular and under-cut to increase the action of the ressure medium thereon, another of the sur aces tting closely within a restricted portion of the aperture, means for limiting the forward movement of the plunger, and a fragile diaphragm normally closing the aper- .ture and bearing lightly against the surface yof the plunger having the smaller area, re-

sponsive to a predetermined pressure for concentrating the pressure upon'the before mentioned' under-cut surface whereby movement of the plunger is. accelerated to establish a passage for the exit of the pressure medium and for maintaining the plunger in its actuated position until the pressure is relieved.

4. In a safety pressure relieving device, a housing having an aperture, a plunger mounted therein having-a pair of surfaces of different areas adapted to be acted upon by a pressure medium, the surface of larger area normally completely closing onel end vof the aperture, the plunger portion having the smaller area exactly tted in the other end of the aperture, means for limiting the for- A

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