US2170056A - Method for automatic indication of inflammable gas admixtures - Google Patents

Method for automatic indication of inflammable gas admixtures Download PDF

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Publication number
US2170056A
US2170056A US150782A US15078237A US2170056A US 2170056 A US2170056 A US 2170056A US 150782 A US150782 A US 150782A US 15078237 A US15078237 A US 15078237A US 2170056 A US2170056 A US 2170056A
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Prior art keywords
gas
combustible
mixing chamber
chamber
explosion
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US150782A
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English (en)
Inventor
Keinath Georg
Gruss Heinz
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Siemens and Halske AG
Siemens AG
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Siemens AG
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N25/00—Investigating or analyzing materials by the use of thermal means
    • G01N25/50—Investigating or analyzing materials by the use of thermal means by investigating flash-point; by investigating explosibility
    • G01N25/54—Investigating or analyzing materials by the use of thermal means by investigating flash-point; by investigating explosibility by determining explosibility
    • 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
    • Y10T436/00—Chemistry: analytical and immunological testing
    • Y10T436/11—Automated chemical analysis

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  • the invention relates to a method of automatic indication of inflammable gas'admixtures which excels by heretofore unattained reliability. It is for this reason also especially suited for continuous determination of the methane percentage in the air of pits or mines?
  • the special advantage resulting from this method is that a given specific arrangement only responds to inflammable gas and thus in the case of examining pit air is only and solely sensitive to methane. In consequence thereof also with other mixtures of inflammable gases or vapors, for instance in' case of illuminating gas, the mixture is according to the Le Chatelier law the .point of response indicated in fractions of the explosion limit concentration. --Besides, the occurrence or non-occurrence of.
  • an explosion caused accordingto the method forms a pronounced limit of reactiomensuring highest possible accuracy, and is to a large extent independent of attendant circumstances, such as ignition tension, temperature etc.
  • the invention excels insofar as high operating temperatures are avoided and the stress on the measuring deviceis re-' Jerusalem to a minimum in consequence thereof.
  • ac-- cordance with the invention by making a certain percentage of the inflammable gas explosive by automatically regulated vapour concentration by means of evaporating an additional combustible.
  • the explosiveor non-explosive character is preferably made use of as indication for exceeding or remaining below the limiting concentration.
  • additional combustible in particular a solid body for which purpose naphthalene has proved to be especially suited. point of naphthalene, to mix it with beta naphthol.
  • additional evaporating substances viz. liquids or solid bodies: is especially suitable since with them only the one condition has to be complied with, that a, certain temperature of the evaporating substance be ensured.
  • a, certain temperature of the evaporating substance be ensured.
  • For enlarging the surface of the evaporating liquid use may be made of a wick arranged at the element regulating the temperature to a constant value.
  • naphthalene in flaked form hasv however a, disadvantage insofar as, owing to the desirable operating temperature being close to the melting point of naphthalene (805) sintering of the flakes is difficult to avoid, so that in this case it cannot be guaranteed that the naphthalene follows into the space which'has been gradually evacuated through consumption of naphthalene by evaporation.
  • this drawback may be avoided according to the invention by using the substance in the solid form, of a candle, for instance, in the form of a cast cylinder, which exactly fits the evaporation space and during its consumption is shoved into the Space evacuated by the evaporation of the material, preferably with the aid of spring action.
  • the gas to be examined is preferably introduced into the evaporation space with as low a velocity as possible so as to keep, on the one hand, the dimensions of the apparatus and, on
  • the application 'of the method according to the invention has shown, that the explosion pressure and the threshold values of ignition are to a large extent independent of the size of the explosion space and the energy and the tension of the ignition spark. But of some importance is the influence of the external air pressure on the explosion pressure.
  • the evaporating naphthalene causes in the mixture a constant partial pressure independent of the level of the barometer.
  • the explosion threshold per se of a naphthalene-air mixture is determined, however,
  • the temperature point, at which this box closesthe heating current in consequence of the .vapor pressure will be dependent on the air pressure in obedience to the same law according to which the percentage of a substance evapcrating at constant temperature in air, depends on the level of the barometer. For this reason the evaporation space should practically not be maintained at a constant temperature, but be regulated to a temperature, from which results a constant vapor pressure difference of the expansion liquid with respect to the prevailing atmospheric pressure. In order that the percentage of the admixed vapor may remain independent of the external air pressure, the following conditions must be complied with:
  • a given 70 slope ofthe vapor pressure curve of the substance employed for the regulation of the temperature shows, for instance, a mixture of pentane and hexane.
  • Figure 1 is a transverse section on line I'I in Figure 2, while Figures 2 and3 are sectional elevations following the lines 2-2 and 3-3, respectively, of Figure 1;
  • Figure 2 represents the contact arm I3 of Figure 2 in plan view, and
  • Figure 4 represents a wiring diagram of the circuits used in the operation of the device.
  • a metal block i in a metal block i is provided a.
  • cylindrical chamber I for the naphthalene candle 2 which is contained in a guide tube 3, suitablyfixed in the chamber, and from which it is forced against the retaining screen l near the bottom of the evaporating space 4 by means of a spring 3.
  • Tube 3 is heat-insulated from block I by an annular air space 3' so as to protect the candle 2 from the temperature variations of block I which occur'during the operation of the device.
  • the explosion chamber 5 connected with the saturation space 4 by a duct 6.
  • a spark plug I arranged at the bottom of chamber 5 serves for igniting the mixture.
  • the pressure due to an explosion occurring when a certain methanepercentage is exceeded, is transmitted to a contact 9 by means of a Sylphon bellows manometer 8.
  • this contact which may set into action any suitable connections, warning signals or similar apparatus, as will be referred to later, may not remain closed too short a time in accordance with the only short duration of an explosion
  • the manometer is preferably accorded retardation lasting a few seconds by the insertion of a conventional check valve III which quickly opens and flies against stop pins I8 in response to the explosion gas pressure and admits gas into the manometer, thereby rapidly closing contact 9, while it is-then immediately reciosed by the gas pressure in the manometer which at that time exceeds the pressure in chamber 5, because the latter in the meantime has been vented at 5
  • the gas is discharged from the manometer only gradually through a conventional vent it in the valve body.
  • the voltage for the igniting spark is derived from the transformer II, rigidly attached to the metal block I.
  • a synchronous motor I2 and a timing element I 3 rotated thereby serve for intermittent connection of the spark plug to the transformer terminal II and the frequency of this connection and the duration of the sparks may be determined at will depending on the construction of the timing element ii, i. e., upon its circumferential length and whether it has one or several contact fingers which contact with the spark plug terminal. In the present case only one contact finger I3 is shown in Figure 2.
  • the desired temperature value corresponding to-a given percentage of inflamm mable gas, may be adjusted by the screw I8 which controls the distance between thermostat capsule l5 and spring l5 and which may be located in a suitable circuit, such as is shown at 22, H3 in Figure 4.
  • This circuit inclLdes the current source 15 S and the previously mentioned heating element 22 in block I.
  • the temperature regulator screw l8 may be provided with a scale, not shown, permitting of adjusting the various concentrations of the inflammable gas by turning the screw l8.
  • the voltage transformer II is also used, apart from generating the igniting spark, for oscillating the diaphragm l6 of the diaphragm pump whichpumps the gas mixture to be examined into the saturation space 4.
  • the magnetic flux of this transformer is closed by diaphragm it which, as will be noted, is spaced from the transformer core by an air gap.
  • the diaphragm is; mounted in front of the lower nozzle ll.
  • the diaphragm oscillates at the frequency of the supplied alternating current and produces in this case an air current in the two nozzles ll, due to their shape and relative positions, which in the upper nozzle is augmented by an action based on the ejector principle to such an extent that the air attains the required velocity thereby and is forced through the saturation space 4.
  • the air is taken in through the intake passage l'l provided in block I.
  • Diaphragm pumps of this character are well known in the art and therefore the detail description of this pump and the principle on which it is based-has been omitted.
  • the method according to the invention may, apart from the manner described, also be applied by adjusting the heating value to a constant value in such a manner, that when the mixture exceeds a certain percentage of inflammable gas, explosion and in consequence thereof indication will result.
  • the degree of the temperature to be maintained at a constant value may beselected according to the desired permissible limit of the percentage of the inflammable gas.
  • the described apparatus solves the problem of 65 automatically reporting in the manner of a relay when a certain percentage of inflammable gas or vapor is exceeded or not reached. If however, the problem is to be dealt with to determine or record the often varying percentage of inflam- 70 mable gases, the heating serving forthe evaporation of the additional combustible may be automatically stopped or-be put out of commission by. an explosion, until at further ignition attempts no further explosions occur, whereby the which this may be accomplished is shown dia-. grammatically in- Figure 4.
  • a tilting toggle relay 25 is provided which is held by its armature 28 and springs 3
  • contact 30, which controls the heating current of cartridge 22 remains closed, except that it is subject to the control of contact l8, previously described.
  • the manometer contact at 9 is opened and the left-hand coil 29 of relay 25 is deenergized, so that by the continued repeated energization of the right-hand coil 29 the relay 25 is tilted back into the position shown in Figure f1, in which it recloses heating contact 30 and in which it remains until again an explosion occurs.
  • the temperature of the apparatus will in consequence thereof vary in the vicinity of a value corresponding to a certain percentage of inflammable gas.
  • Method of automatically and continuously testing for the presence of a dangerous amount oicombustible in an atmosphere consisting in passing the gas to be tested continuously through a reaction chamber, evaporating solid naphthalene admixed with beta naphthol into the test gas at constant vapor concentration to render the gas explosive, and in supplying intermittently an ignition'spark to the entire gas and vapor mixture.
  • Method 01 automatically and continuously testing for the presence of'a dangerous amount of combustible in an atmosphere, consisting in passing the gas to be tested continuously through a reaction chamber, evaporating solid naphthalene into the test gas at constant vapor concentration to render the gas explosive, in supplying intermittently an .ignition spark to the entire gas and vapor mixture, and in continuously feeding the naphthalene, so that at all times the sameamount of evaporated solid is contained in the gas mixture.
  • Method of automatically and continuously testing for the presence of a dangerous amount of combustible in an atmosphere consisting in pass ing the gas to be tested continuously through a reaction chamber, evaporating an additional solid stored combustible to the saturation point into the test gas to render the latter explosive, supplying intermittently an. ignition spark to the entire gas and vapor mixture, and in controlling the evaporation temperature of said combustible to a given value, so that when the inflammable gas admixture exceeds a permissible percentage an explosion of the entire mixture by the spark will occur.
  • Arrangement for automatically indicating the permissible percentage of inflammable gas admixtures to a surrounding atmosphere including a mixing. chamber, a combustion chamber communicating with said mixing chamber and means for supplying the test gas through said mixing chamber to said combustion chamber, means for constantly supplying a solid combustible to said mixing chamber, heating means for evaporating said solid combustible at a constant vapor concentration into the test gas in said mixber communicating with said mixing chamber and means for supplying the test gas through said mixing chamber to' said combustion chamber, means for constantly supplying a solid combustible to said mixing chamber, heating means for evaporating said solid combustible at a constant vapor concentration into the test gas in said mixing chamber, intermittently actuated ignition means in said combustion chamber to explode the entire mixture when it contains a given amount of inflammable gas admixture, means controlled.
  • Arrangement for automatically indicating the permissible percentage of inflammable gas admixtures to a surrounding atmosphere including a mixing chamber, a combustion chamber communicating with said mixing chamber and means for supplying the test gas through said mixing chamber to said combustion chamber, means for constantly supplying a solid combustible to said mixing chamber, heating means for evaporating said solid combustible at a constant vapor concentration into the test gas in said mixing chamber, intermittently actuated ignition means in said combustion chamber to explode the entire mixture when it contains a given amount of inflammable gas admixture, a diaphragm capsule containing a liquid mixture having a given vapor pressure curve and means controlled by the response of said capsule to varying atmospheric pressures for actuating said combustible heating means in accordance with the pressure conditions of the atmosphere, so that the combustible vapor concentration variations due to varying atmospheric pressure are compensated .by the reactions of the pressure on said capsule.
  • Arrangement for automatically indicatin the permissible percentage of inflammable gas admixtures to a surrounding atmosphere including a solid block of suitable material, having a mixing chamber, a combustion chamber communicating with said mixing chamber, a solid combustible disposed in the upper portion of said mixing chamber and means for constantly pushing said combustible toward the lower end of said mixing chamber, a heating chamber in said block containing a heating device for evaporating said combustible substance into said mixing chamber and a temperature control chamber in said block containing a temperature control device, means connected with said block of inflammable gas admixture, and means actuated by said temperature control device for controlling said combustible heating means in accordance with the pressure conditions of the atmosphere, so that the combustible vapor concentration variations due to varying atmospheric pressure are compensated by the reactions of said pressure on said temperature control device and said heating means.
  • Arrangement for automatically indicating the permissible percentage of inflammable gas admixtures to a surrounding atmosphere including a solid block' of suitable material, having a mixing chamber, a combustion chamber communicating with said mixing chamber, a solid combustible disposed in the upper portion of said mixing chamber and a spring for constantly pushing said combustible toward the lower end of said mixing chamber, a heating chamber in said block containing a heating device for evaporating said combustible substance 'into said mixing chamber and a temperature control chamber in said block containing a temperature control device, means connected with said block for constantly supplying the test gas through said mixing chamber into said combustion cham-' ber, intermittently actuated ignition means in said combustion chamber for exploding the entire mixture when it contains a given amount of inflammable gas admixture, and means actuated by said temperature control device for controlling said combustible heating means in accordance with the pressure conditions of the atmosphere, so that the combustible vapor concentration variations due to varying atmospheric pressure are compensate
  • a. combustion chamber communicating with, said mixing chamber and means for supplying the test gas through said mixing chamber to said combustion chamber, means for constantly supplying a solid combustible to said mixing chamber, heating means for evaporating said solid combustible at a constant vapor concentration into the test gas in said mixing chamber, intermittently actuated ignitionpmeans in said combustion chamber to explode the entire mixture when it contains a given amount of inflammable gas admixture, means for controlling said combustible heating means in accordance With the presure conditions of the atmosphere, so that the vapor concentration variations due to varying atmospheric pressure are compensated by the reactions of said pressure on said heating means, and a Sylphon bellows manometer connected to said combustion chamber and having a contact element actuated by said manometer at the occurrence of an explosion, and aneIectric circuit arrangement including said contact and said heating means for cutting out said heating means when an explosion occurs.
  • Arrangement for automatically indicating the permissible percentage of inflammable gas admixtures to a surrounding atmosphere including a mixing chamber, a combustion chamber communicating with said mixing chamber d a diaphragm pump for supplying the test gas through said mixing chamber to said combustion chamber, means for constantly supplying a solid combustible to said mixing chamber, heating means for evaporating said solid combustible at a constant -vapor concentration into the test gas in said mixing chamber, intermittently actuated ignition means in said combustion chamber to explodethe entire mixture when it contains a given amount of inflammable gas admixture, and means for controlling said combustible heating means in accordance with the pressure conditions of the at mosphere, so that the vapor concentration variations due to varying atmospheric pressure are compensated by the reactions of said pressure on said heating means.
US150782A 1936-05-23 1937-06-28 Method for automatic indication of inflammable gas admixtures Expired - Lifetime US2170056A (en)

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2673339A (en) * 1952-02-25 1954-03-23 James W Gray Gas detector
US2943919A (en) * 1956-01-20 1960-07-05 Berardi Vincenzo Device for detecting combustible gas
US3090038A (en) * 1959-06-08 1963-05-14 Great Lakes Pipe Line Company Hazardous atmosphere detecting and signalling system
EP3633363A1 (de) 2018-09-20 2020-04-08 Anton Paar ProveTec GmbH Elektrozündung für flammpunkttester

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2673339A (en) * 1952-02-25 1954-03-23 James W Gray Gas detector
US2943919A (en) * 1956-01-20 1960-07-05 Berardi Vincenzo Device for detecting combustible gas
US3090038A (en) * 1959-06-08 1963-05-14 Great Lakes Pipe Line Company Hazardous atmosphere detecting and signalling system
EP3633363A1 (de) 2018-09-20 2020-04-08 Anton Paar ProveTec GmbH Elektrozündung für flammpunkttester
DE102018123097B4 (de) 2018-09-20 2021-12-16 Anton Paar Provetec Gmbh Elektrozündung für Flammpunkttester
US11635207B2 (en) 2018-09-20 2023-04-25 Anton Paar Provetec Gmbh Electric ignition for flashpoint tester

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GB487281A (en) 1938-06-17
BE421688A (xx)
FR822148A (fr) 1937-12-21

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