CA1199990A - Rupture disc alarm system - Google Patents

Abstract

Abstract A monitor system for sensing the failure of a rupture disc and activating an alarm in response to such a failure.
The system also senses potential failure of a rupture disc.
The system includes a failsafe signal carrying loop which is broken when the rupture disc fails, thereby interrupting the signal. The system also includes a signal sensor which recognizes a signal interruption or substantial modification in the signal and initiates and cooperates with an alarm device to provide notice to an operator or a safety device that the rupture disc has failed.

Description

"3~

RUPTURE DISC ALARM SYSTEM

8 Background of the Invention 9 The present invention relates to a failsafe monitoring system for detecting actual or impending failure of a 11 rupture disc and providing an alarm when such a failure 12 occurs.
13 The most frequent utilization of a rupture disc is in 14 pipelines which are normally unused vent passageways in a chemical process system but which are intented to provide 16 safety relief should some process vessel or conduit over or 17 under pressurize, thereby creating a hazardous condition.
18 The rupture disc, by its nature, is usually hidden from vie~J
`19 and, therefore, it is often difficult to visually determine when failure thereof has occurred. Even when it is obvious 21 to an observer that failuLe of a rupture disc has occurred, 22 such as when a gas or liquid fluid is suddenly venting or 23 flowing into an open area where none should be, it is still 24 important that the failure be noticed as quickly as possi-ble, since the fluid may ~e hazardous and/or explosive, and26 since some type of safety equipment or procedure may be 27 immediately required to protect personnel and/or equipment.
28 For example, it may be necessary to shut off a pump to stop 29 the discharge.
Conventional rupture disc alarm systems typically ~ ' 9~

l require that a portion of a broken disc engage a sensing

2 probe or similar device before an alarm is sounded. A disc

3 failure, however, can be sufficiently explosive or unpre-

4 dictable in operation to leave no par~s in position for engaging the probe or the probe itself can be rendered -6 inoperative due to damage or electrical failure. Also, the 7 probe systems typically do not detect potential failure of a 8 disc, such as the stretching thereof to a predetermined 9 percentage of the failure point. Further, conventional systems normally detect failure of a disc in only one ll direction r thus requiring multiple systems. Still further, 12 probe systems are usually difficult to install and require ; 13 special mounting parts and procedures~ In addition, con-14 ventional alarm systems are often not failsafe, whereby they do not sound an alarm in case of part failure or loss of 16 power.
17 It is noted that pressure switches have been utilized 18 to sense failure of a rupture disc; however, such switches l9 can only ~e used in closed systems wherein pressure will build downstream of a broken rupture disc and thus activate 21 the switch, especially if the escaping fluid has a low 22 pressure diferential across the disc and slow flow rates.
23 It is therefore desirous to have a failure sen~ing device 24 which will function in open as well as closed systems and-particularly in low pressures.
26 It is also noted that rupture discs are often used in 27 areas wherein there is a potential for explosion. ~herefore 28 parts of a rupture disc in the explosive area should be 29 intrinsically safe ~lectrically and otherwise explosion proof.

U ~ects of the Invention Therefone,the objects of the present invention are:
to provide a monitoring system for detecting failure in a rupture disc and notifying operatin~ personnel or modifying operating equipment in response to such a failure; to provide such a system for also detec-ting impending or partial failures of rupture discs; to provide such a system which can detect fail-ure in two directions; to provide such a system which is fail-safe în design; to provide such a system comprising a signal carrying circuitor loop which is interrupted or otherwise mod-ified by failure or impending failure of the rupture disc and a signal sensor which detectssuch a modifîcation of the signal passing through the loop and activates an alarm; to provide such a system wherein failure of any portion thereof interrupts the signal and activates the alarm and is, therefoxe, essentially failsafe; to provide such a system wherein the loop may înclude an intrinsically safe electrical signal passing therethrough;
to provide such a system which will function in both closed and open systems, at low pressures; to provide such a system which is relatively easy to install in conjunction wîth a rupture disc;
to provide such a system having a sîgnal carrying loop which is easily and sîmply replaced along with an associated rupture disc after failure of the latter; to pro~ide such a system which is econom~cal to produce, positi~e in operation, easy to use, and particularly well adapted for the proposed usage thereof~
Thus, in accordance with one broad aspect of the inven-tion, there is provided a monitorlng system for detectîng alt~r-ations in a deformable member of a rupture d.isc assembly; said system comprising: (a) generating means for producing a signal;
(b) signal carrying means in touching relationship --3~

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and positioned on said deformable member and transmitting said signal therethrough when said member is not deformed; said carrying means having a modifiable transmission capacity and being sensit~veto alterations in said deformable member such that th~ carrying means transmitted signal is modified when alterations occur in said deformable member; (c) sensor means cooperating with said generating means and said carrying means for detecting said transmitted signal; said sensor means having the capacity to determine when said transmit-ted si.gnal has been modified a predetermined amount and triggering a response at a location remote from said deformable member indicating that said signal has been modified said predetermined amount; and~d) alarm means remote from said deformable member and being trigg-ered by said sensor means upon said transmitted signal being : modified said predetermined amount; (e) whereby said alarm means is activated whenever said deformable member is altered a suff~cient amount to modify said transmitted signal said prede-termined amount~
In accordance with anothex broad aspect of the invention there is provided a rupture disc assembly for relief of excess-ive fluid pressure in at leastone direction in processing equ:ip-ment and for triggering an alarm located remotely from said assembly when such relief occurs; said ~ssembly comprisi.ng:
(a) a rupturable seal positioned to operably block.flow of fluid through a conduit communicating with the process~ng equipment dur~ng normal operating conditions; said seal xupturlng and allowing flow of fluid during conditions of excess~ve fluid pressurein the pxocess~ng equipment; (b) support means securing said seal prior to rupture thereof in said.conduit; (c) generat-in~ means developiny a si~nal comprising a reference level of energy; (d) carrying means cooperat.ing with said generat~ng means to transmit said signal; said carrying means being pos~tioned in ~3a-touching re].at.ionship with respect to and extending along said seal and being physically altered By a change in condition in said seal thereby modifying said signal; (e) sensor means coop-erating with said generating means and said carrying means and monitoring said signal after transmission by said carrying means, said sensor means detecting a change in the transmitted signal and producîng a response to such a change; and (f) alarm means remote from said seal and cooperating with saîd sensor means and being activated by said response after a predetermined level of change in the transmitted signal; (g) whereby when the condition of said seal changes a sufficient amount to produc~ said pre-determined ~evel of change in the transmitted signal, said alarm is activated.
In accordance with another broad aspect of the inventlon there is provided~ in combination: (a) a rupture disc seal ! having opposed sides for blocking flow of fluid through a passageway until a differential pressure between said sides exceeds a predetermined level whereupon said seal ruptures;
and (b) a conduit having a pathway adapted for transmitting a signal from one end thereof to an opposite end thereof; said conduit being fixedly attached to said seal such that said pathway is broken and incapable of transmitting a signal when said seal ruptures; said conduit also being adapted to commun-~cate with alarm means such that when said pathway is unBroken said signal is transmitted to sa~d alar~ means and when said pathway ~s broken said signal is not transmitted to sa;d ~larm means thereby act~vating said alarm means.
other objects and ad~antages of th;s ~nvention w~ll become apparent from the following descript~on taken in conn-ection with the accompanying drawings where~n are set -3b-9C~

1 forth by way of illustration and example, certain embodiments 2 of this invention.

4 Summary of the Invention A monitoring system is provide for detecting total, 6 partial and/or impending failure of a rupture disc which 7 blocks passage of fluids through a conduit and activates an 8 alarm when such a failure occurs. The system comprises a 9 signal caxrying circuit or loop, a signal sen~or and an alarm mechanism. The signal carrying loop is part of, ll adjacent t~ or in close association with the rupture disc to 12 be monitored, such that a modification of the disc also 13 creates a signal modifying change in the signal carrying 14 loop. In one embodiment of the invention the signal is an electrical current; the signal carrying loop is an electrical 16 circuit which varies in resistance if broken or otherwise 17 modified; and the signal sensor i6 a device ~o sense change ;18 in the electrical signal caused by variance of thë resis-19 tance in the circuit. In another embodiment of the in-vention, the signal is an optical wave or light generated by 21 a suitable source, the signal carrying Loop is a light 22 transmitting optical fi~er, and the sensor includes means 23 such as a photocell which is responsive to changes in light 24 intensity or level. The signal sensor may be adjusted to ~etect actual failure and/or stretching of the rupture disc 26 to a predetermined percentage of failuxe. The alarm mecha-27 nism may notify operating personnel~ activate safety equip-28 ment, and/or modify process equipment when failure or 29 impending failure of a rupture disc is detected.
The drawings constitute a part of this specification 1 and include exemplary embodiments of the present invention 2 and illustrate various objec-ts and features thereof.

k Brief Descri tion of the Drawinqs P_, .
S Fig. 1 is a partially schematic side elevatlonal view 6 of a rupture disc relief assembly incorpOrating a disc 7 failure monitoring system according to the present inven-8 tion.
9 Fig. 2 is an enlarged vertical cross-sectional view of 10 the relief assembly as shown in Fig. 1.
11 Fig. 3 is a transverse cross-sectional view of the 12 relief assembly taken along line 3-3 of Fig. 2 with portions 13 broken away to show detail thereof.
14 Fig. 4 is an exploded perspective view of a portion of the relief assembly.
` 16 Fig. 5 is a fragmentary cross~sectional view of the i 17 relief assembly taken along line 5-5 of Fig. 3.
` 18 Fig. 6 is a perspective view of a rupture disc and `19 signal carrying loop for the rupture disc assembly~
Fig. 7 is a fra~mentary cross-sectional view of the 21 rupture disc and signal carrying loop as shown.
Ij ~ 2~ Fig. 8 is a perspective view of a modified rupture disc 23 and signal carrying loop.
~: 24 Fi~. 9 is a cross-sectional view of a second modified rupture disc incorporating a signal carrying loop.
, 26 Material thickness in the drawings may in some places 27 be exaggerated for illustrative purposes.

29 Detailed Description of the Preferred Embodiment ~s required, detailed embodiments of the present inven-:

_ 5_ ~ 3~

1 tion are disclosed herein; however, it is to ~e unders~ood 2 that the disclosed embodiments are merely exemplary of the 3 invention which may be embodied in various fvrms. There-4 fore, specific structural and functional details disclosed herein are not to be interpreted as limiting, hut merely as 6 a basis for the claims and as a representative basis for 7 teaching one skilled in the art to variously employ the 8 pre5ent invention in virtually any appropriately detailed g structure.
For purposes of description herein in the terms 11 "upper", "lower", "vertical", "horizontal", and derivatives 12 thereof along with other directional references shal relate 13 to the invention as oriented in Figs. 1 through 3; however, 14 it is to be understood that the invention may assume vario~s alternative orientations, except where expressively specified 16 to the contrary. / ~i 17 The reference numeral 1, as shown in Fig. 1, generally 18 designat~s a rupture disc assembly inc]uding a rupture disc 19 failure monitoring system 2, according to the present in-vention, positioned between two spaced portions 3 of a 21 conduit such as the illustrated vent pipe 4 or the like. In 22 normal operation the assembly 1 is secured to the vent pipe 23 poxtions 3 by suitable means such as bolted flanges~ weldin~, 24 treaded engagement, clamps or the like, such that the assem-bly 1 is secured in place and fluid is prevented from seep-26 age between the interconnection thereof with the vent pipe 27 portions 3. As used herein the term "fluid" means both 28 gases and liquids.

29 The a~sembly 1j normally blocks flow of ~luids in either direction alony the vent pipe 4. The vent pipe 4 9~

1 generally communicates with processing equipment such as 2 positive and negative pressure vessels (not shown) and 3 provides relief for excessive pressure conditions therein.
; 4 In order to relieve from one vent portion 3 to the other, the blockage provided by the assembly 1 is ruptured or 6 otherwise removed.
7 The assembly 1, as is partially shown in Fig. 4, ~ comprises an outlet crown 10, a perforated top section 11, a 9 deformable member~ disc t or rupturable seal 12 having a portion of the monitoring system 2 attached thereto, a lower 11 vacuum girdle 14, and an inlet crown 15 having a knif~ blade 12 assembly 16 mounted therein. Pins 20 pass through aper~ures 13 21 in and ~ecure against horizontal rotary m~vement of t~e top 14 section 11, the seal 12 and the girdle 14 relative to the crowns 10 and 15, A quick disconnect sanitary type band 22 16 extends around and secures together proximate circumferéntial 17 flanges or edges 23 and 24 of the crowns 10 and 15 re~
18 spectively, see Fig. l, with an outer annular flange portion 19 25 of the seal 12 secured therebetween. It is ~oreseen that the assembly 1 could vary greatly within the conventional 21 art of rupture disc protection devices requiring only a 22 rupturable type seal which is deformed and/or broken by 23 excessive positive and/or negative pressure and which 24 functions in cooperation with the monitoring system 2.
In the particular assembly 1 illustrated in Fig~ 4, the 26 top section ll is 2 fo~ard type rupturing disc-having a 27 perfora~ed and radially grooved, cut or slit concave-convex 28 portion 26 and a relatively flat annular flange portion 27.
29 The section 11 is similar to that type shown in U.S~ Patent 3,88~,629.

1 The seal 12 illustxated in ~ig. 4 is constructed of a 2 material suitably impermeable to whatever fluid will be 3 blocked thereby. A suitable material may be a flexible 4 plastic such as tetrafluoroethylene and co-polymers, such as are marketed under the trademark "Teflon". The seal 6 material and thickness thereof is selec~ed so as to be 7 frangible or stretchable to such a degree that rupture 8 occurs when a preselected positive or negative pressure 9 differential is reached on opposite sides thereof. In some rupture disc assemblies, a seal will not be externally 11 supported. However, in Fig~ 4 both the section 11 and the 12 girdle 14 support the seal 12 against certain positive and 13 negative pressure differentials respectively. The seal 12 14 should also be able to withstand slight but rather con~
tinuous flexing which occurs due to frequently changing 16 pressure differentials without fatigue failure. Although 17 the seal may take many various shapes or forms including 1~ flat, the illustrated seal 12 has a concave-convex interior 19 portion 30 to which the flange 25 is secursd. Frequently, a convex side of the seal 12 substantially mates with a 21 concave side of the section 11; however, in some prewarning ~2 installations, it is desired to determine when a pressure 23 differential between opposite sides of the seal 12 has 24 reached a certain percentage of that differential which will cause rupture of the seal 12. In such prewarning installa-26 tions, the seal 12 may be spaced from or ha~e a somewhat 27 different curvature as compared to the section 11. It is 28 foreseen that the seal 12 could be a wide variety of non-29 metallic or metallic materials such as aluminum. The girdle~
14 may be any suitable support structure preventing the seal 1 from buckling or reversing until a preselected negative 2 pressure differential is reached. The illustrated girdle 14 3 has an outer annular flange 31 and three stays 32. The 4 stays project upwardly and inwardly so as to mate with the convex side of the seal 12. The top section flange 27, the 6 seal flange 25, and khe girdle flange 31 are preferably co-7 extensive with each other and with the proximate crown 8 flanges 23 and 24-such that a seal is formed therebetween to 9 prevent seepage of fluid from ~he interior to the exterior of the assembly 1. Suitable gaskets or gasketing sealant 11 may be utilized where necessary to produce such a fluid 12 seal.
13 The cutting member or knife blade 16 has three radiating 14 arms 33 extending upwardly near an axis thereof and joining with the inlet crown l5. The upper end of each arm 33 is 16 sharpened so as to ~orm a cutting ed~e 34. The knife blade 17 16 is aligned with the girdle 14 such that the girdle stays 18 32 do not engage the cutting edge 34 if the stays 32 are ~19 deformed ~oward the inlet crown 15. The cutting edge 34 is aligned so as to engage, impale, and rupkure the seal 12 21 should the latter be deformed in such a manner to invert or 22 buckle, that is, wherein the normal concave side of the seal 23 12 would become a convex side and vice versa.
24 In the illustrated embodiment the crowns 10 and 15, the -25 section 11, the girdle 14, the band 22 and parts associated 26 therewith function as s~pport means 36 for the seal until 27 the la~ter is ruptured.~ It is seen that the seal support 28 means 36 could be very complex or very simple depending on 29 the type of assembly utilized. It is also seen that the seal could function as part of the support means 36 for ~ 3~

1 example by combining the girdle 14 and seal 12 illustrated 2 into a single unit.
3 The monitoring system 2 comprises generating means 40, 4 signal carrying means 41, sensor means 42 and alarm means 43.
Ç The generating means 40 may be any suitable device for 7 producing a signal and is shown in Fig. 1 by the box denoted 8 "signal generator". Preferably the generating means 40 9 produces a "pulsating" or continuous signal, although it is forseen that any definable varyiny signal ~ould be utilized 11 provided that proper cooperation with the sensor means 42 is 12 provided such that-an undefined ~ariance in the signal could 13 be detected as will be described below. The generating 14 means 40 may produce an electrical, optical, fluid flow, or other suitable signal depending on the particular system 16 utilized. The illustrated,generating means 40 produces an 17 electrical current haviny a predetermin~d reference energy 18 level. Supply of such~an electrical current may be accom-19 plished by utilizing a conventional public power supply from an A.C. electrical line, producing an electrical current 21 with a generator or battery, or transforming one of the 22 previously mentioned supplies into a suitable signal. As 23 many installations require an intrinsically safe, that is a 24 suficiently low voltage and amperage electrical system to avoid possible fires or explosions, it is preferable that 26 the electrical ~urrent and voltage be sufficiently low to 27 avoid such dangerous energy levels capable of igniting 2~ explosive atmospheres. Transfoxmation o standard A.C.
29 electrical supply to produce an electrical current within the nature of 6 volts D.C. and less than O~l M amperes 1 has been found to generate a suitably failsafe signal when coupled with proper resistence throughout the system 2. It 3 is noted that where no electricity can be tolerated within : 4 the system, the optical signal may be utilized. The genexating means for an optical system could constitute a ; 6 light or optical wave producing mechanism such as a bulb, 7 light emitting diode or laser and an associated optical .8 fiber to transmit the light.
9 The said carrying means 41, as illustrated in Figs. 1 throuyh 5, comprises a circuit, conduit, or loop 50 which 11 transmits a signal from the generating means 40 to the 12 sensor means 42. The loop 50 passes in close proximity ~o 13 the seal 12 and is preferably secured thereto or equiva-14 lently to another deformable member of the assembly 1. The lS loop 50 has the capacity to be altered when an.associated 16 seal 12 is defor~ed, such as when the seal 12 is ruptured, 17 although in some installations the loop 50 is altered or 18 modified when the seal 12 is simply flexed or stretched..
19 without rupturing. Preferab.ly alteration of the loop 50 20 produces a proportional modification in the level of energy 21 of the sign~l txansmitted thereby as compared to the re-2~ ference level of energy produced by the generating means 40.
23 In the illustxated embodiment the loop 50 includes a ~24 shielded cable or conduit comprising a first wire 56 from the signal device or generatiny means 40 whlch joins with . 26 one end 52 of a U-shaped wire 53, as best seen in Fig. 3, at 2/ a ~uick type terminal or connector 5~. An oDposite end 55 28 of the U-shaDed wire 53 joins at the connector with a second 29 wire Sl which is electrically connecteâ to the sensor means 42. In this manner an electrical circuit from the generating ~ 9~

1 means 40 to the sensor means 41 is completed, provided the 2 U-shaped wire 53 remains intac~.
3 Preferably the U-shaped wire 53 has a resistance whlch 4 varies in inverse proportion to the cross-section thereof.
Hence, as the seal 12 deforms, ~he wire 53 is stretched 6 causing the latter to also deform and, in particular, to 7 change in cross-section. Such a change in crvss-section 8 increases the resistance of the wire which in turn modifies 9 or alters the signal being transmi~ted by the loop 5Q. Of 10 course, if the seal lZ ruptures, the loop 50 is broken, 11 thereby modifying the transmitted signal and, in particular, 12 completely interrupting the signal. The loop 50 may be 13 broken by overstretching under tensile forces or by being 14 cu~ by the cutting edge 34 f 1 ) The loop 50, as shown, comprises a thin conductor or lÇ U ~haped wire 53 of an electrically conducting metal or 17 other suitable conducting material, such as gold, copper, 18 graphite, or the like. A metal wire or foil may be deposited 19 directly on a non-conducting seal 12 by metal plating, ~0 sputtering, vacuum deposition, silk screening~ or the like.
21 Preferably, the conductor 53 is insulated from the rem,ainder 22 of the assembly 1 by a suitable insulator 59, such as a 23 polyester base film or the like. In the Figures, the 24 insulator 59 is clear so that integrity of the 130p 50 can 25 be visually checked~ Also , preferably, the loop 5Q and 26 insulator 59 there~or are attached to the seal 12 by direct 27 application or suitable adhesive ~not shown), ~uch as'a 28 'silicone adhesive or the like or the loop may be a con-29 ductive adhesive. The loop 50 may be reinforced by tape, conduit or the like between the emergence thereof from the -12~

3~

1 support means 36 and the connector 54.
2 It is noted that the illustrated loop 50 is fully 3 insulated within the vicinity of the assembly 1 while 4 electricity is passing through or being transmitted by the S loop 50. In addition, the loop 50 does not require special 6 pipe or other parts requiring machinery to pass from the 7 interior to the exterior of the support means 36. Also, the 8 system is designed for inherent intrinsic sa~ety.
9 As is illustrated, the loop 50 may be positioned on the convex side of the plastic seal 12~ As seen in Fig. 6 ~ 7, 11 a loop 50a may be positioned on the convex side of a metallic 12 seal 12a. The actual material of construction of a-partic-13 ular seal may vary substantially within the present inven-14 tion. Alternatively, as seen in Fig. 8, a loop 50b may be positioned on the concave side of a seal 12b. Further 16 alternatively a loop 50C may be positioned within and thus 17 be made part of a seal 12c as shown in Fig. 9. It is 18 foreseen that many possible placements o~ a suitable loop 50 19 are possi~le which are not illustrated herein; in partic-ular, placement on the section 11 or girdle 14. Also, Zl multiple use of different loops is possible, such as ~ere 22 it is desirious to continuously measure maximum deformation ~3 which the disc has experienced in either possible direction.
24 The sensor means or signal sensor 42 cooperates with the generating means 40 and, in particular, with ~he signal 26 carrying means 41 and thereby detects the signal transmitted 27 by the latter. The sensor 42-is adapted to detect varia-~8 tions, alterations or modifications in th~ energy level of 29 the transmitted signal. In particular, the sensor means 42 has ~he capacity to respond to a modification of a pre-~ 3~

1 determined amount of a transmitted signal and provide notice 2 to or trigger an alarm or response at a location remote from 3 the seal 12 when the signal has heen modified. The major 4 modification to the signal detected by the sensor 42 occurs when the seal 12 is ruptured, thus breaking the loop 50 and 6 modifying the signal by stopping same completely. However, 7 it is not necessary that the loop 50 break for the sensor 12 8 to provide the notice; in particular, the sensor 42 could be 9 set, programmed or the like to provide notice when a seal expands, stretches or otherwise deforms to indicate that a I 11 certain percentage o the differential pxessure which would 12 cause rupture of the seal 12 has occurred or that fatigue 13 has occured in the seal 12 and ~t should be replacedO
14 Multiple loops 50 each on a respective seal 12 with asso-ciated sensors 42 se~ to give notice at different differential 16 pressures or a sensor 42 programmed to give notice at mul~i-17 ple differential pressures can be utilized to continuously 18 monitor a seal 12 before failuxe thereof without replacement 19 of the seal 12 or loop 50.
~0 The sensor 42 for an electrical signal may be any 21 suitable device for receiving an electrlcal signal, de-22 tecting a change in the signal, and providing a response to 23 the change. Normally the sensor 42 would be displaced from 24 the seal 12. ~or op~ical sighalsl, the sensor means would i , . .
comprise ~ ~evice ~or scnsing the energy of an optical 26 signal, detecting a predetermined change in the energy 27 level, and providing notice of or response to such a change.

28 Such an optical sensor could include a photocell or a ~9 phototransistor cooperating with appropriate circuitry.

The alarm means or alarm mechanism 43, as illustra~ed 9~

1 by the box labelled "alar~ mechanism" in Fig. 1, cooperates with the sensor 4~ such that an alarm is triggered or 3 activated by the notice or response which is provided by the 4 sensor 42, that is, the notice or response that the seal 12 has deformed an amount for which it has been predetermined 6 that something or someone should be notified.
7 The alarm means 43 may be any suitable device such as ( ~ `) 8 a horn, buzzer, flashing light or the like. In addition the 9 alarm means 43 may simply constitute transmission of a secondary signal such as the notice provided by the sensor 11 means 42. Such a secondary signal can be utilized to activate 12 safety equipment, initiate a change in operating equipment 13 such as stopping a pump, or the like.
14 Preferably the alarm means 43 is activated by failure of the various components of the system 2 and, in particu-16 lar, by failure of the generating means 4Q, the carrying 17 means 41 or the sensor means 42. This may be accomplished 18 by having the same power suppl~ which operates the various 19 components of the system 2 cooperate w.ith the alarm means 43, such that when power is on the alarm means 43 is activated ~1 only by the sensor means 42 but when power fails to the 22 entire system 2 or to one of the components thereof, then 23 the alarm means 43 is also acti~ated thereby makiny the 24 system 2 ~ailsae, in that failure of any of the components of the system ~ activates a warning alarm thus preventing an ~6 undetected failure of the seal 12 when the system 2 is not 27 ~unctional 28 The above described system 2 may be utilized: with 29 standard rupture discs, reverse buckling discs, or graphite discs; as a component part in composite discs or double 1 acting discs; as a leak detector, provided the leak modifies 2 the seal; as a pressure detector in a pipeline; to detect 3 fatigue or overpressure of a disc thereby predicting failure 4 before same occurs; or the like.
In operation~ the system 2 is installed, as shown in 6 the figures for example, in conjunction with a seal 12 and 7 support means 36 therefor in a vent pipe 4 or the like, 8 thereby forming a complete assembly 1 for blocking f~ow of 9 fluid through the pipe 4 until an excessive differential pressure occurs on opposite sides of the seal 12 at which 11 time the disc or seal 12 fails or ruptures allowing flow of 12 the fluid through the pipe 4. The sys~em 2 detects rup~ure 13 of the seal 12; in particular, a signal is produced by tha 14 generating means 40 and transmitted by the carrying means 41 to the sensing means 42 be~ore failure. The carrying means 16 41 is broken when ~he seal 12 breaks, thus stopping trans-17 mission o the signal. The sensor means 42 detects that the 18 signal has stopped and activates the alarm means 43.
19 ~or detection of an impending failure of a seal i2, the above process is the same except that the seal 12 deforms 21 but does not deform sufficiently to break. ~he loop 50 22 deforms with the seal 12 and thus alters or modifies the 23 siynal. The sensor means 42 detects that the signal has 24 been modified and when the modification o~ the signal drops to a predeterminal level or amount, the sensor means 42 26 activates the alarm means 43.
27 Therefore, the method or process for detecting failure~
28 of the seal 12 o~ the assembly 1 comprlses: genera~ing a 29 detectable signal, passing the si~nal through carrying means 41 closely associated ~7ith the seal 12 which carrying means 1 41 is modifiable by changes in condition of ~he seal 12, 2 monitoring the signal after passing the seal 12, determining 3 when a significant change has occurred in the signal after 4 passing the seal 12, and relaying an alarm to a location

5 remote from the seal 12 when such a significant change in

6 the signal has occured.

7 It is to be understood that while certain embodiments

8 of the present invention have been described and shown

9 herein, it is not to be limited to specific forms or

10 arrangement of parts herein described and shown~ except

11 insofar as such limitations are included in the following

12 claims.

13

14 2~

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Claims (15)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A monitoring system for detecting alterations in a deformable member of a rupture disc assembly; said system comprising: (a) generating means for producing a signal, (b) signal carrying means in touching relationship and positioned on said deformable member and transmitting said signal therethrough when said member is not deformed, said carrying means having a modifiable transmission capacity and being sensitive to alterations in said deformable member such that the carrying means transmitted signal is modified when alterations occur in said deformable member; (c) sensor means cooperating with said generating means and said carrying means for detecting said transmitted signal; said sensor means having the capacity to determine when said transmitted signal has been modified a predetermined amount and triggering a response at a location remote from said deformable member indicating that said signal has been modified said predetermined amount; and (d) alarm means remote from said deformable member and being triggered by said sensor means upon said transmitted signal being modified said predetermined amount; (e) whereby said alarm means is activated whenever said deformable member is altered a sufficient amount to modify said transmitted signal said predetermined amount.

2. The system according to claim 1 wherein: (a) said signal is electrical, and (b) said signal carrying means comprises an electrical circuit.

3. The system according to claim 1 wherein: (a) said signal is a light beam, and (b) said signal carrying means comprises a light transmitting optical fiber.

4. The system according to claim 1, 2 or 3 wherein: (a) said deformable member is rupture disc seal;
and (b) said carrying means is physically attached to said seal in such a manner that when said seal ruptures, then said carrying means is broken thereby interrupting and thus modifying said transmitted signal.

5. The system according to claim 1, 2 or 3 wherein: (a) said deformable member is rupture disc seal;
(b) said carrying means is physically attached to said seal in such a manner that when said seal ruptures, then said carrying means is broken thereby interrupting and thus modifying said transmitted signal; (c) said seal deforms by stretching before rupture thereof; and (d) said carrying means deforms with said seal and has the capacity to modify the signal transmitted thereby in substantive proportion to the stretching of said seal; (e) whereby when said seal is stretched a prespecified amount then said signal is modified said predeteremined amount such that said alarm means is activated.

6. The system according to claim 2 wherein: (a) said carrying means comprises an electrical current carrying wire being attached to said seal to stretch therewith and having a varying resistance related to the cross-sectional area thereof; the cross-sectional area of said wire varying in proportion to the stretching of said seal.

7. The system according to claim 3 wherein: (a) said alarm is acti-vated whenever said signal is modified by means external to said system;
and (b) said alarm is activated whenever said sensor fails to function;
whereby said system is failsafe.

8. A rupture disc assembly for relief of excessive fluid pressure in at least one direction in processing equipment and for triggering an alarm located remotely from said assembly when such relief occurs; said assembly comprising: (a) a rupturable seal positioned to operably block flow of fluid through a conduit communicating with the processing equipment during normal operating conditions; said seal rupturing and allowing flow of fluid during conditions of excessive fluid pressure in the processing equipment; (b) support means securing said seal prior to rupture thereof in said conduit; (c) generating means developing a signal comprising a reference level of energy; (d) carrying means cooperating with said generat-ing means to transmit said signal; said carrying means being positioned in touching relationship with respect to and extending along said seal and being physically altered by a change in condition in said seal thereby modifying said signal, (e) sensor means cooperating with said generating means and said carrying means and monitoring said signal after transmission by said carrying means, said sensor means detecting a change in the transmitted signal and producing a response to such a change, and (f) alarm means remote from said seal and cooperating with said sensor means and being activated by said response after a predetermined level of change in the transmitted signal, (g) whereby when the condition of said seal changes a sufficient amount to produce said predetermined level of change in the transmitted signal, said alarm is activated.

9. The assembly according to claim 8 wherein: (a) said generating means comprises an electrical power supply (b) said signal is electrical, and (c) said carrying means comprises an electrical circuit.

10. The assembly according to claim 9 wherein:
(a) said seal is stretchable to a predetermined limit before rupturing, (b) a portion of said circuit is attached to said seal such that said circuit is stretched whenever said seal is stretched, and (c) said circuit modifies the signal being transmitted thereby upon stretching.

11. The assembly according to claim 10 wherein:
(a) stretching of said circuit decreases the cross section thereof; thereby changing the electrical resistance thereof.

12. The assembly according to claim 9 wherein:
(a) said electrical circuit includes an electrical supply being in the nature of not more than approximately 6 volts D.C. and not more than approximately 0.1 M amperes; whereby (b) said electrical circuit is generally intrinsically safe for use in conjunction with explosive fluids in said conduit.

13. The assembly according to claim 8 wherein:
(a) said sensor means produces a continuous impulse upon reception of the signal transmitted by said carrying means unless said predetermined level of change has occurred in said transmitted signal and sends said impulse to said alarm means; said impulse being stopped by mechanical and electrical failures of said sensor means; said alarm means being maintained in a non-activated tate when receiving said impulse and being in an activated state when not receiving said impulse; whereby said alarm means is activated when said sensor means fails and when said signal is modified said predetermined level of change, such that said system is substantially failsafe.

14. In combination: (a) a rupture disc seal having opposed sides for blocking flow of fluid through a passageway until a differential pressure between said sides exceeds a predetermined level whereupon said seal ruptures;
and (b) a conduit having a pathway adapted for transmitting a signal from one end thereof to an opposite end thereof;
said conduit being fixedly attached to said seal such that said pathway is broken and incapable of transmitting a signal when said seal ruptures; said conduit also being adapted to communicate with alarm means such that when said pathway is unbroken said signal is transmitted to said alarm means and when said pathway is broken said signal is not transmitted to said alarm means thereby activating said alarm means.

15. The combination according to claim 14 including: (a) generating means for producing a signal and delivering said signal to said conduit one end; (b) sensor means for receiving a transmitted signal from said conduit opposite end, sensing an interruption of said signal, and producing a response to such an interruption; and (c) alarm means being triggered by said response.