US3775622A - Device for the suppression of reactions involving undue pressure rise in large-size containers - Google Patents

Device for the suppression of reactions involving undue pressure rise in large-size containers Download PDF

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Publication number
US3775622A
US3775622A US00299405A US3775622DA US3775622A US 3775622 A US3775622 A US 3775622A US 00299405 A US00299405 A US 00299405A US 3775622D A US3775622D A US 3775622DA US 3775622 A US3775622 A US 3775622A
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United States
Prior art keywords
output
input
pressure
amplifier
contact assembly
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Expired - Lifetime
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US00299405A
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English (en)
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G Fredericks
R Zeiringer
K Wiederwohl
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LIST H OE
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Individual
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J19/0006—Controlling or regulating processes
    • B01J19/002—Avoiding undesirable reactions or side-effects, e.g. avoiding explosions, or improving the yield by suppressing side-reactions
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D90/00—Component parts, details or accessories for large containers
    • B65D90/22—Safety features
    • B65D90/32—Arrangements for preventing, or minimising the effect of, excessive or insufficient pressure
    • B65D90/34—Venting means
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J2219/00049—Controlling or regulating processes
    • B01J2219/00245—Avoiding undesirable reactions or side-effects
    • B01J2219/0027—Pressure relief
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00—Fluid handling
    • Y10T137/7722—Line condition change responsive valves
    • Y10T137/7758—Pilot or servo controlled
    • Y10T137/7761—Electrically actuated valve

Definitions

  • a device for the suppression of reactions involving undue pressure rise in large-size containers having an explosive or thermo-chemically reacting contents comprising a pressure sensor exposed to the internal pressure of the container controlling a pressure reliev- ABSTRACT ing device via two parallel-connected contact assemblies, one of the contact assemblies responding to the transgression of a predetermined value of the internal pressure of the container and the second contact assembly responding to the transgression of a predetermined pressure rise per unit of time.
  • This invention relatesto-a device forithe suppression of reactionsinvolving: undue pressureriser-in large-size. containers carrying. explosivev or thermo-chemical charges, comprising a pressure sensor and a'pressurerelief-unit controlled by thev latter.
  • the first'contact assembly is an analog to-digital converter and the-second" contact assembly'is a differentiating circuit followedby ananalogvto-digitalconverter by means ofan-amplifier;
  • analog-to-digitalconverters consisting of'a differential amplifier whose negative-output. is connectedby means of a resistor 'to a'voltage regulator'fed 1 by areference voltage.
  • the voltage regulator-:the'threshold of operation 'of theanalog-to-digital converters can be altered and adapted togiven'requirementszwhen necessary. In normal conditions, the-out-z puts of thetwo analog-to-digital converters are. set to;
  • the first analogto-dig'ital. con verter switches to logical 1 when thecontainerpressure has exceeded the predetermined limit.
  • the secondianalog+to-digital converter switches to logical 1 only when the output voltage of the differentiating circuit which isproportionate to the riseper unit of time of the con tainer'pressure, has exceeded thepredeterminedvalue;
  • this circuitry operation is to produce a hysteresis on the threshold of operation of the analogto-digital converter, which means that although the analog-to-digital converter may be switched on as soon 4 tainers are shown'in FIG. 1.
  • the ordinate shows 'the container pressure Pex on a logarithmic scale and the abscissa the time t'also on a logarithmic scale.
  • the diagram area is subdivided into monitoring areas I,v II, and
  • the pressure sensor is made to follow apreamplifier preferably combined ,with it so as to produce a structural unit. This provides a possibility for producing a long cable connection between the measuring element and the rest of the electronic circuit.
  • the low-pass filter serves to filter out undesirable frequencies and the area of operations of the device further narrowed 'asrequired.
  • Anothterembodirnent of the invention comprises an additional circuit for ,the suppression of I thermochemical reactions, comprising a monostable switchstep followed by a pulse sharper connected to the output of the first connecting assembly, a reversing stage connected to theoutput of the second connecting assembly and a bistable switch-step followed by a power amplifier, with the block input of the bistable switchstep being connected with the output of the pulse sharper, the preparatory input of the bistableswitchstep with the output of the reversing stage, and the bistable switch-step being reset, if required, by means of aswitch' into the initial position.
  • This additional circuitry makes it possible to detect and suppress also thermo-chemical reactions for which a relatively slow rise of pressure is characteristic and whichare, therefore, located below the response limit of the second contact assembly.
  • the output voltage of the additional circuitry can, for example, be used to actuate a relay controlling the aperture of air evacuation valves. In this way the container where in the thermo-chemical process takes place and which is unable to withstand the pressure to be expected, can be protected from damage and even destruction.
  • FIG. '1 shows a diagram of the monitoring borders of a device according to the invention
  • FIG. 2 the schematic diagram of the electronic sector of the device
  • FIG. 3 a pressure sensor as part of the device according to the invention
  • FIG. 4 a variant of this pressure sensor.
  • Knowledge of the pattern of pressure developments inherent in explosions and other reactions involving rise of pressure is above all necessary for their suppression.
  • These pressure developments per unit of time as may arise in view of different parameters in closed con- III defined by the releasing pressures adjustable within sure rise values P and P
  • pressure patterns coming within the monitoring area I should not produce and releasing functions in the device.
  • the monitoring area I is subdivided into two sectors a and b, the sector a being limited against diminishing pressure gradients by grad P with 0.1 at/us. This limitation results from the knowledge that larger gradients than 0.1 at/us are safely precluded from occurring during explosions.
  • voltage patterns with gradients of that size occur at the input of the electronic circuit hereafter described in greater detail, they may be safely presumed to be caused by lightning strokes, atmospheric conditions or by mains interference.
  • Curve A in the diagram stems'from such an electronic interference signal the limits of 0.05 to 0.5 atmospheres and'the' two pressimulating a pressure .pattem in the diagram which is actually non-existant in the container.
  • the second sector 17 of the monitoring area -I is that pressure range inside which operational pressure variations caused by example, by the opening and closing of for example, should not release fire-extinguishing or other pressure-relieving measures either.
  • the monitoring area Il comprises all pressure patterns that are characteristic for dustand-gas explosions.
  • the monitoring area II is defined by two constant pressure gradients P and P on the one hand, and by the releasing pressure adjustable within the range from 0,05 to 0,5.
  • Curve C shows a typical pressure pattern for dust-and-gas explosions. Any pressure pattern arising inside area Ilmust positively release the fire-extinguisher.
  • the monitoring area III covers the field wherein thermo-chemical reactions, such as for example, selfignition of the contents of the container, occur. For these processes an initially slow and flat pressure rise is a characteristic feature. 0nly then will an explosion actually occur and the blast pressure valve proper superposes itself on the flat pressure rise. A curve pattern 7 which is typical for thermo chemical reactions of this kind is reproduced in curve D.
  • fire-extinguishers are actuated via a special channel or other measures are released to inhibit the nascent explosion.
  • combating measures depend on the type ofplant to be protected. For example,
  • the input of this circuit is a pressure transducer 1 which responds not only to pressure variationsbut also to the absolute value of pressure. It can be of the active orpassive transducer variety, that is, capable of producing a voltage itself, such as for example, a quartztype transducer or it canbe fed by means of a-source of power of its own, such as for example, a slide-wire bridge.
  • the pressure transducerl g is attached to the pressure container (not shown in the drawings) requiring monitoring and directly exposed to '.the pressure prevailinginside the container. Depending on the type and size of container used, one or more pressure trans- .ducers 1 will be provided.
  • the .pressure transducer 1 is followed by a preamplifier-2either attached to the pressure transducer 1 so as to form a single structuralelement, or located in the immediate vicinity of the pressure transducerv 1 so as to provide a long cable connection, if necessary, for the following members of the circuit.
  • the pre-amplifier 2 is followed by a low-pass filter 3 by means of which electric interfering signals of the typeof curve A in FIG. 1 liable to produce an errone- .ous.release of the device, are suppressed.
  • the differentiating circuit 5 designated by symbols only comprises a condenser 9 followed by an operation amplifier 10 whose output and inp'utare .fed back via a resistor l l.
  • the voltage at the output of the differentiatingcircuit 5 is proportional to the rise of the container pressure. measured by meansof the pressure transducer 1 with time,- that is the value dp/dt.
  • the output signal of the differenting circuit 5 amplified in the amplifier 6 passes via aninput resistor 12 to the positive input of a differential amplifier 13 whose output is connected with the positive amplifier input via a reaction resistor l4.
  • the negative input of the differential explosive character comprised in the monitoringarea ll and for the release of adequate suppression measures.
  • the area [I is delimited by the appropriate adjustment of the threshold of operation of the analog-todigital converters 7 and 8 by means of the voltage regulators l6 and 21. If the pressure-proportionate released v 27 of the circuit.
  • the analog-to-digital converter 8 whose output is normally at logical 0 voltage, is set to logical 1.
  • the output signal of the AND-gate 22 triggers the monostable switch step 23 whose output pulse is transformed into a rectangular pulse in the following pulse shaper stage 24.
  • the width of the rectangular pulse can be set as required in a manner'known per se by means of the pulse shaper 24.
  • Therectangular pulse amplified in the amplifiers 25 and -26 is of sufficient capacity to actuate the fire-extinguisher connected to the output
  • an additional circuit amplifier 13 is via an input resistor 15 connected to the .voltage regulator 16 fed by a reference voltage Um.
  • the differential amplifier 13 in conjunction with the resistors l2, l4 and 15 provides the aforesaid analogto-digital converter 7.
  • the second analog-to-digital converter 8 is of the same design as the converter 7 and the pressuredependent voltage released by the amplifier 4 passes via the input resistor 17 to the positive input of the differential amplifier l8 belonging to the analog-to-digital converter 8 whose output is feedback-coupled with the positive input vi'a'a resistor" 19.
  • the negative input of the differential amplifier 18 also is connected via an input resistor 20 to a voltage regulator 21 which likewise lies at the reference voltage U
  • Each of the outputs of the two analog-to-digital converters 7 and 8 is connected to an input of an AND- converter 7 and a bistable switch step 31. followed by a power amplifier 32 whose output is designated by ref-v erence number 33.
  • the output'of the pulse shaper 29 is connected with the clock input of the bistable switch step 31 and the output of the reversing stage 30 with the preparatory input of the bistable'switch step 31.
  • the bistable switch step 31 is moreover, reversible into its initial position by means of a switch 34.
  • the reference pressure emanates from a device not shown consisting of a pressure flask and a pressure-reducing valve.
  • the reducing nozzles of this reference-pressure producer are so adjustable that both typical pressure patterns of dust or gas explosions and thermo-chemical reactions can be simulated.
  • Another possibility of checking the efficiency of the monitoring device as shown in FIG. 4 consists in the impingement of the inside of the transducer membrane by means of reduced pressure.
  • the transducer 1 whose housing also includes the pre-amplifier 35, to stay connected with the container 37 under control also during the checking operation. No stop cock is therefore necessary.
  • the transducerl is provided with a tubulure 41 by means of which the transducer membrane 38 can be impinged upon with underpressure. This underpressure is again supplied by an operation testing unit connected to the transducer to be checked by means of a hose. The size or time slope of the underpressure will be set in such a manner that it will produce at the transducer output designed as a connecting plug 42 the same signal as a gas explosion or a thermo-chemical reaction would.
  • the transducer 1 is preferably attached to the wall of the large-size container by means of a clamp bolt 43 engaging a taphole of the container wall and pressing a front-face flange 44 of the transducer housing against a gasket 45 inserted in the receiving bore of the large-size container'37.
  • a device for the suppression of reactions involving undue pressure rise in large-size containers with an explosive or thermo-chemically reacting contents comprising at least one pressure sensor exposed to the internal pressure of the container and having an output delivering an electric signal corresponding to the internal pressure, two contact assemblies each having an input and an output, the inputs of the two contact assemblies being connected in parallel and connected with the output of the pressure sensor, the first'of the tact assembly responding to an input voltage designating the transgression of a predetermined pressure increase per unit time and releasing an output signal, an
  • AND-gate having two inputs and an output, the first of said inputs being connectedtto the output of the first contact assembly and the secondinput of the AND- gate connected with the output of the second contact assembly, a pressure-relieving device connected to the output of the AND-gate and releasable by means of the output pulses of the AND-gate.
  • a device providing a first analog-to-digital converter forming the first contact assembly, a differentiating circuit having an-output, an amplifier with an input and an output, the input of the amplifier beingconnected with the output of the differentiating circuit, a second analog-to-digital converter connected to the output of the amplifier, the differentiating circuit, the amplifier and the second analogtodigital converter forming the second contact assembly, each of the two analog-to-digital converters comprising a differential amplifier having a positiveinput, a negative input and an output, a resistor preceding the negative input of the differential amplifier, a voltage regulator fed by means of a reference voltage, the negative inputs of both differential amplifiers being, connected via the resistors to the voltage regulator.
  • a device providing a preamplifier inserted between the output of the pressure sensor and-the parallel-connected inputs of the two contact assemblies.
  • a device wherein the pressure sensor and the pre-amplifier are combined so as to constitute a common structural unit.
  • a device providing a lowv pass filter connected between theoutput of the said pre-amplifier and the parallel-connected inputs of the two contact assemblies.
  • a device comprising an additional circuit for the suppression of thermo-chemical reactions, comprising a monostable switch step with an input and an output, the input of the monostable switch step being connected with the output of the first contact assembly, a pulse shaper with-an input and an output, the input of the pulse shaper being connected with the output of the monostable switch step, a reversing stage with an input and an output, the input of the reversing stage being connected with the output of the second contact assembly, a bistable switch step having a clock input, a preparatory input, a resetting input and an output, the clock input of the bistable switch step being connected with the output of the pulse shaper, the preparatory input being connected to the output of the reversing stage and the resetting input connected with a switch for the resetting of the bistable switch step into the initial position.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Measuring Fluid Pressure (AREA)
US00299405A 1971-11-04 1972-10-20 Device for the suppression of reactions involving undue pressure rise in large-size containers Expired - Lifetime US3775622A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
AT953771A AT314427B (de) 1971-11-04 1971-11-04 Einrichtung zur Bekämpfung von mit unzulässigem Druckanstieg verbundenen Reaktionen in Großbehältern

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US3775622A true US3775622A (en) 1973-11-27

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US00299405A Expired - Lifetime US3775622A (en) 1971-11-04 1972-10-20 Device for the suppression of reactions involving undue pressure rise in large-size containers

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US (1) US3775622A (enExample)
AT (1) AT314427B (enExample)
CH (1) CH544911A (enExample)
DE (1) DE2250166B2 (enExample)
FR (1) FR2160012A5 (enExample)
GB (1) GB1378810A (enExample)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4641683A (en) * 1984-07-24 1987-02-10 Voith Turbo Gmbh & Co. Kg Valve arrangement for controlling the flow of mediums
US4777383A (en) * 1987-06-01 1988-10-11 Ldi Pneutronics Corp. Electrically controlled variable pressure pneumatic circuit
US5396923A (en) * 1992-10-28 1995-03-14 Allen; Donald M. Surge relief apparatus and method

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3408970C1 (de) * 1984-03-12 1985-07-11 Winfred 8000 München Klink Druckempfindliche Sensoreinrichtung für einen Alarmsignalgeber
US5561610A (en) * 1994-06-30 1996-10-01 Caterpillar Inc. Method and apparatus for indicating a fault condition
US6031462A (en) * 1998-11-03 2000-02-29 Fike Corporation Rate of rise detector for use with explosion detection suppression equipment

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3402972A (en) * 1966-08-11 1968-09-24 Gen Electric Continuous pressure control system
US3628563A (en) * 1968-12-10 1971-12-21 Tokyo Shibaura Electric Co Explosion detecting means for a fluid pipeline
US3665945A (en) * 1971-02-03 1972-05-30 M & J Valve Co Valve control system and method
US3726307A (en) * 1971-12-09 1973-04-10 Cameron Iron Works Inc Pressure control apparatus
US3732887A (en) * 1971-10-12 1973-05-15 Sanders Associates Inc Flow-pressure control valve system

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3402972A (en) * 1966-08-11 1968-09-24 Gen Electric Continuous pressure control system
US3628563A (en) * 1968-12-10 1971-12-21 Tokyo Shibaura Electric Co Explosion detecting means for a fluid pipeline
US3665945A (en) * 1971-02-03 1972-05-30 M & J Valve Co Valve control system and method
US3732887A (en) * 1971-10-12 1973-05-15 Sanders Associates Inc Flow-pressure control valve system
US3726307A (en) * 1971-12-09 1973-04-10 Cameron Iron Works Inc Pressure control apparatus

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4641683A (en) * 1984-07-24 1987-02-10 Voith Turbo Gmbh & Co. Kg Valve arrangement for controlling the flow of mediums
US4777383A (en) * 1987-06-01 1988-10-11 Ldi Pneutronics Corp. Electrically controlled variable pressure pneumatic circuit
US5396923A (en) * 1992-10-28 1995-03-14 Allen; Donald M. Surge relief apparatus and method

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Publication number Publication date
FR2160012A5 (enExample) 1973-06-22
GB1378810A (en) 1974-12-27
DE2250166B2 (de) 1976-11-25
CH544911A (de) 1973-11-30
AT314427B (de) 1974-04-10
DE2250166A1 (de) 1973-05-17

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