US3815552A - Method of and apparatus for generating, maintaining or re-establishing a vacuum in a vacuum vaporization apparatus for heating one or more liquids - Google Patents

Method of and apparatus for generating, maintaining or re-establishing a vacuum in a vacuum vaporization apparatus for heating one or more liquids Download PDF

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Publication number
US3815552A
US3815552A US00368525A US36852573A US3815552A US 3815552 A US3815552 A US 3815552A US 00368525 A US00368525 A US 00368525A US 36852573 A US36852573 A US 36852573A US 3815552 A US3815552 A US 3815552A
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Prior art keywords
vacuum
temperature
vacuum vessel
measurement value
fluid medium
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Expired - Lifetime
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US00368525A
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English (en)
Inventor
Z Koula
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Stotz und Co AG
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Stotz und Co AG
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Priority claimed from DE19722228510 external-priority patent/DE2228510C3/de
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
    • F24H9/00—Details
    • F24H9/20—Arrangement or mounting of control or safety devices
    • F24H9/2007—Arrangement or mounting of control or safety devices for water heaters
    • F24H9/2035—Arrangement or mounting of control or safety devices for water heaters using fluid fuel
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
    • F24H1/00—Water heaters, e.g. boilers, continuous-flow heaters or water-storage heaters
    • F24H1/0009—Water heaters, e.g. boilers, continuous-flow heaters or water-storage heaters of the reduced pressure or vacuum steam type
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
    • F24H1/00—Water heaters, e.g. boilers, continuous-flow heaters or water-storage heaters
    • F24H1/48—Water heaters for central heating incorporating heaters for domestic water
    • F24H1/50—Water heaters for central heating incorporating heaters for domestic water incorporating domestic water tanks

Definitions

  • the present invention relates to a new and improved method of generating, maintaining or re-establishing a vacuum in an apparatus working according to the vacuum vaporization principle, the apparatus'serving for heating one or a number of liquids which are separated from one'another, and furthermore, pertains to a new and improved construction of apparatus for the performance of the inventive method.
  • Equipment of the previously mentioned type is, for instance, known from German patent 1,270,258.
  • Such . is constructed in'a manner that during the thermally conductive connection with'an evacuated vessel, the so-called vacuum vessel or container, partially filled with a vaporizable heating fluid medium, there is provided a separate heat exchanger for each liquid to be heated. All of the heat exchangers are practically exclusively heated by the vapor of the vaporizable heating fluid medium.
  • This'type of equipment is particularly used'as ahot water heater, wherein as a general rule there are provided two heat exchangers. One of the heat exchangers serves to heat the water of a circulation heating installation, the other is designed as a .boiler, and serves to heat-up the consumable water; the
  • heating fluid medium likewise can be, for instance, water..ln the discussion given hereinafter, unless there is otherwise specifically stated, the description will proceed with such hot water heater as its starting basis.
  • Such type hot water heaters possess a number of decisive advantages in contrast to hot water heaters of different construction.
  • the vessel in which the heating fluid medium is vaporized must be evacuated. Previously this was regularly accomplished by means of a vacuum pump. Since it is also essential that the vacuum remains unchanged during the entire operatingtime the aforementioned vessel must be vacuum-tight welded and together with the therewith connected boiler jackets and control devices must be thoroughly checkedwith respect to its vacuum tightness prior to evacuation or at least, prior to placing the equipment into operation. If impairment of the vacuum occurs during operation owing to the presence or occurrence of only slight leaks, then the advantageous characteristics of such. boilers. rapidly diminish. This is apparently attributable to .the fact that air which has penetrated cannot simply uniformly distribute in the evacuated compartment.
  • this air together with possibly prevailing hydrogen formed from chemical decomposition products of the heating medium, especially water, and the wall material of the evacuated vessel forms a gas cushion, so that such locations can be no longer properly heated by the vapor of the heating fluid medium.
  • German patent 270,722 there is knownto the art a technique for generating a vacuum in a relatively small vacuum vessel, according to which. initially a small opening is produced in one of the walls of the vacuum vessel and thereafter the heating fluid medium, namely water, is brought to a state of boiling. Consequently, the air isexpelled and now the opening is again closed, so that during cooling a negative pressure prevails in the vacuum vessel.
  • the heating fluid medium namely water
  • This technique is basically only. suitable for the incipient generation of the vacuum, not however for maintaining a vacuum which has once been outfitrated or for re-establishing a vacuum when the same has been impaired, since producing the opening prior to heating brings with it of necessity a complete pressure equalization between the interior of the vacuum vessel and the atmosphere.
  • Another object of the present invention relates to a simplified method of, and apparatus for, generating as well as maintaining or re'-establishing a vacuum in equipment of the previously mentioned type duringits operation.
  • the invention contemplates that the vaporizable heating 'fluidmedium is heated to such an extent until an excess or overpressure prevails in the initially sealed vacuum vessel, and that the'vacuum vessel is first then briefly brought into flow communication with the atmosphere'until the excess pressure has at least partially decreased.
  • the evacuation operation can be undertaken either periodically independently of the condition of the vacuum, for instance once to five times per year, but however as a precautionary matter according to requirements as a function of a measurement value which is dependent upon the state of the vacuum.
  • the inventive method possesses a number of different decisive advantages. initially the scalability check can be limited to a minimum or completely eliminated. Further, there is dispensed with the necessity of generating vacuum-tight welding connections at the vacuum vessel and between such and the connected boiler jackets and control devices.
  • the equipment for carrying out the method is manifested by the features that at least one shut-off element is provided by means of which it is possibleto place into flow communication with the atmosphere the region of those locations internally of the vacuum vessel which are situated furthest from the vaporization locality of the heating fluid medium, and there is also provided a control means which brings about opening'of the shut-off element after reaching a predetermined excess pressure in the vacuum vessel-and again closes the shut-off element upon reaching a pressure in the vacuum vessel which at least corresponds to the atmospheric pressure.
  • shut-off element for this purpose a special vent valve which operates analogous to an overpressure valve or can be electrically actuated or directly or indirectly by a pressurized medium.
  • a pressure limiting device which is anyway present with insulations of the previously mentioned type and the function of which will be considered more fully hereinafter, it is however possible to dispensev with a special vent valve.
  • the equipment of the invention advantageously incorporates a control elementwhich during evacuation reduces or completely suppresses the withdrawal of heat by the heat exchanger or heat exchangers.
  • the evacuationoperation can be readily initiated manually, since carrying such out once or twice per heating period is sufficient as a general rule.
  • a timer clock or equivalent for periodically initiating evacuation there also can be provided.
  • the equipment such that evacuation occursas a function of a measurement magnitude or value which furnishes information about the state of the vacuum, and if necessary is automatically carried-out.
  • the vessel to be evacuated is provided with at least one measurement value transmitter which delivers a measurement value regarding the state of the vacuum, and there is also provided means whichautomaticallyinitb ates the evacuation operation upon exceeding or falling below respectively, a predetermined boundary value. of the measurement value.
  • the measurement value for the state of the vacuum there can be employed, for instance, the quantity of airpresent in the evacuated vessel, for instance determined bymeans of an ionization chamber or a Geissler tube.
  • Such measurement value transmitters are, however, expensive, so that it is advantageous to employ as the measurement value the temperature and/or.
  • the measurement value for the state of the vacuum there can be employed as the measurement value for the state of the vacuum the behavior of two temperatures, of which one is measured at a location of the evacuated vessel at which there can form a cushion of non-condensed gases, the other temperature being measured at a location at which such cushion does not form, or there can be employed the relationship of the temperature of the heating fluid medium to the temper ature of the liquid heated by the heat exchanger, especially the" return flow of a circulation heating installation.'In such cases there are provided 'two temperature sensors or feelersarranged at appropriate locations.
  • the measurement value for the state of the vacuum there can be employed as the measurement value for the state of the vacuum also the relationship of the temperature which is measured at one locality of the evacuated vessel where there can form a cushion of non-condensed gases to the pressure in the evacuated vessel.
  • a temperature feeler and a pressure feeler at appropriate locationspln the event that the initiation of the evacuation occurs automatically on the basis of a measurement value which provides information concerning the state of the vacuum, then there can'be provided means which terminate the evacuation operation upon exceeding or falling below a predetermined boundary value thereof or another measurement value of the evacuation operation. If the evacuated vessel is provided with a pressure sensor or feeler then there is advantageously employed the measurement value delivered thereby for terminating the evacuation operation.
  • the evacuation operation is simply permitted to take place during a fixed predetermined time duration and after the expiration thereof is interrupted.
  • a simple timer which determines the duration of the evacuation operation.
  • the loss in heating fluid medium occurring during venting amounts, as a general rule, only to a few cubic centimeters and there'- fore is so slight that the time duration can be employed with a relatively large safety margin. For this reason it is possible, as mentioned, to carry out with foresight, the
  • heating fluid medium In any event an additional liter of heating fluid medium is sufficient for an operating duration of at least 5 to 2.0 years. Larger losses in heating fluid medium are determined in any event by the conventionally available safety temperature limiting device which safeguards the installation against running dry.
  • the hot water heater depicted by way of example in FIG. 1 will be seen-to comprise a combustion compartment or chamber 2 heatedby a suitable heating source 1, for instance gas.
  • a suitable heating source for instance gas.
  • the infeed of thermal energy is controlled by a heating energy gate or valve HES.
  • the combustion compartment 2 is formed by the lowermost portion of the evacuated vessel or container 4 and which is filled with water 3, and in the vaporcompartment 5 of which there is arranged a heat exchanger 6 of a circulating heating installation provided with a circulating pump P.
  • the major portion of the boiler 7 is surrounded by the vapor compartment 5, this boiler serving to generate and store hot water which is to be consumed.
  • I 1 The control of the hot water heater occurs during normal operation, for instance, by means of a vessel thermostat KTh and the boiler thermostat BTh.
  • a safety temperature limiter or limiting means STB arranged in the part of the evacuated vessel 4 filled with water 3, this temperature limiting means safeguardingthe installation against running dry. i.e. operating in a dry state;
  • a pressure limiter or limiting means DB arranged in the vapor compartment 5 of the evacuated vessel 4, this pressure limiting means safeguarding the installation against exceeding a predetermined maximum pressure; both elements (STB and DB) act upon the heating energy valve or gate HES;.and
  • a mechanically operating-safety valve SV which also can be constructed as arupturable membrane or the like, and safeguards the installation directly against exceeding a predetermined maximum pressure.
  • a gas cushion 8 forms at ,the uppermost region or portion of the vapor compartment 5.
  • This gas cushion 8 primarily consists of air, however can also contain hydrogen from the-chemical decomposition'of the water with the wall material of the evac uated vessel 4. This portion and if necessary still other parts of the vapor compartment 5 are connected with the'venting or vent .valve EV. The slight quantity of at the flue. i
  • the measurement value transmitters or sensors GI and GII For controlling the evacuation operation on the basis of the condition of the vacuum there can be provided at the indicated locations the measurement value transmitters or sensors GI and GII; also the pressure limiting device or pressure limiter DB when suitably constructed can serve as the measurement value transmitter GII.
  • the pressure limiting device or pressure limiter DB when suitably constructed can serve as the measurement value transmitter GII.
  • a special resetting measurement value transmitter RG for controlling the evacuation operation on the basis of the condition of the vacuum there can be provided at the indicated locations the measurement value transmitters or sensors GI and GII; also the pressure limiting device or pressure limiter DB when suitably constructed can serve as the measurement value transmitter GII.
  • a special resetting measurement value transmitter RG For the termination of the evacuation operation there can be provided a special resetting measurement value transmitter RG.
  • a consumable water lock or valve BS For preventing the removal of the consumable water from theboiler 7 during the evacuation operation there can be provided a consumable water lock or valve BS.
  • This circuit functions as follows: upon actuation of the starting switch AS (depicted position), whether such be manually, or by virtue of the action of the pulse transmitter IG, the normal control or regulation of the hot water heater depicted in FIG. 1 is bridged in such a manner that the delivery of thermal energy of the heating system to the heating coil 6a of the heat exchanger 6 of the circulation heating system is prevented in that the circulation pump P is placed out of operation and the possibly provided consumable water valve or gate BS (FIG. 1) isclosed.
  • the water 3 in the evacuated vessel 4 is immediately heated-up by the complete output of the heating source 1.
  • the pressure in the evacuated vessel 4 climbs until reaching an excess pressure of about 0.3 to 0.5 atmospheres, depending upon the response pressure of the pressure limiting means DB.
  • the vent valve EV will automatically open and at the same time the timer ZG responds which, for instance, can be constructed as a bimetallic element.
  • the undesired gas cushion 8 together with a small quantity of water vapor escapes. The ejected air separates from the water vapor in the separator Sep and escapes into the ambient surroundings, and the quantity of water collected in the separator Sep slowly evapo-.
  • FIG. 3 there is depicted a simple and very inexpen sive automatically operating circuit in which the withdrawal of thermal energy by the circulation heating installation notthrottled.
  • This circuit operates on the basis of the measurement values of two measurement value transmitters GI and Gll.
  • the measurement valuetransmitter GI is temperature-dependent and arranged in the zone where there can form a gas cushion.
  • the other measurement value transmitter GII can be temperature-dependent or pressure-dependent and is arranged externally of the zone where there can form a gas cushlOI'l.
  • the measurement value transmitter GII measures the temperature or the pressure in the evacuated vessel 4 and can be a thermostat or a pressure switch. During a random heating-up'phase, for instance during heating-up of the boiler the measurement value transmitter GII closes upon reaching a temperature of 100C or a pressure of l atmospheres absolute.
  • the vent valve EV is actuated via the measurement value transmitters GI and GI! and is opened until the upper portion, after venting of the gas cushion, has been heatedup beyond 95C by the vapor atmosphere which is now again present.
  • the measurement value transmitter GI therefore opens at for instance 95C and the vent valve EV is again closed.
  • the vessel upon switching-off the vessel thermostat KTh or the boiler themostat BTh, can be further furnished with thermal energy in the evacuation phase parallel contacts of the measurement value transmitters GI and GII shunt or bridge the vessel control.
  • the circuit depicted in FIG. 3 only operates upon transition from the negative pressure region into the excess pressure region.
  • Both of the measurement value transmitters GI and Gil operate in the same manner and aresimilarly arranged as for the circuitry of FIG. 3. If both measurement value transmitters GI and Gil are closed then the relayR has a voltage applied thereto and is energized. As soon as it has'been energized it must be held via the restoring measurement transmitter RG and the contact r since the measurement value transmitter Gl after reaching a predetermined temperature, for instance C, has switched-off. The contact r 'bridges the vessel thermostat KTh and the boiler thermostat 8171, so that in any event the complete output of the heat source 1 can be transferred-to the water 3 in the evacuated container 4. I I I
  • the contact r blocks the removal of energy bythe circulation heating system in that the circulating pump P is switched-off. If desired, the relay R possesses a further contact r which also blocks-via a consumable water gate or valve BS the. removal of hot consumable water from the boiler].
  • the pressure limiting means or limiter DB switches via the already closed contact r the vent valve EV into its open position.
  • the vent valve EV into its open position.
  • the restoring measurement value transmitter RG opens. This is for instance formed as a thermostat which is set to C and which switches as soon" as the escaped medium has reached this temperature, which means that it is now no longer airrather vapor.
  • a start- 7 GII the pressure in the evacuated vessel 4-.
  • the measurement value transmitter GI opens before the measurement value transmitter 611 closes.
  • the pressure climbs quicker than the water temperature and the measurement value transmitter GII closes before the measurement value transmitter GI opens.
  • both the measurement value transmitter GI as well as also the measurement value transmitter GII as temperaturesensitive measurement value transmitters and to ar range both of them at the upper portion of the evacuated vessel 4 (phantom lined position of measurement value transmitter GII).
  • both of the measurement value transmitters will be lo cated in the vapor atmosphere and thus register the same temperature.
  • the vacuum is poorer, that is to say, the gas cushion becomes that much greater then the upper measurement value transmitter G is surrounded by the gas cushionand the temperature thereat drops, whereas the temperature at the lower measurement value transmitter GII remains unchanged.
  • I I I A method of generating, maintaining or reestablishing a vacuum in avacuum vessel of an apparatus working according to the vacuum vaporization principle for heating one or a'number of liquids which are separated from one another, wherein a heating fluid medium is heated and the vacuum vessel which at this improvement comprising the steps of heating the heating fluid medium to such an extent until in the initially sealed-off vacuum vessel there prevails an excess presduring evacuation.
  • shut-off element comprises venting valve means.
  • venting valve means is an electrical vent valve
  • venting valve means is a pressure actuated venting valve.
  • shut-off element comprises avalve constituting a pressure limiting means which within the excess pressure region or latest during drop of the excess pressure to the atmospheric pressure switches into its closed state.
  • shut-off element is a valve comprising a safety valve which within the excess pressure region or latest during drop'of the excess pressure to the atmospheric pressure switches and again closes.
  • the vacuum vessel is equipped with at least one measurement value transmitter delivering a measurement value for the state of the vacuum, and means for automatically initiating evacuation upon exceeding or falling below a predetermined boundary value of the measurement value.
  • the measurement value transmitter comprises a Geissler tube which is operatively associated with the vacuum vessel.
  • said measurement value transmitter comprises two temperature feelers, one of said temperature feelers being arranged at the region of the location of the vacuum vessel which is furthest removed from the vaporizationlocation of the heating fluid medium, the other temperature feeler being arranged at a location which is closer to the vaporization location of the heating fluid medium.
  • said measurement value transmitter comprises two temperature feelers, both of said temperature feelers being arranged at the region of the location of the vacuum vessel which is located furthest from the vaporization locality of the heating fluid medium in such a mannet that upon the formation of a gas cushion at such region one of the temperature feelers is enclosed sooner by the gas cushion than the-other temperature feeler.
  • the measurement value transmitter comprises a temperature feeler which is arranged at the region of the location of the vacuum vessel which is furthest removed from the vaporization location of the heating fluid medium, and a pressure feeler for measuring the pressure in the vacuum vessel.
  • the measurement value transmitter comprises two temperature feelers, one of the temperature feelers measuring the temperature of the heating fluid medium, the other

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Drying Of Solid Materials (AREA)
  • Heat-Pump Type And Storage Water Heaters (AREA)
US00368525A 1972-06-12 1973-06-11 Method of and apparatus for generating, maintaining or re-establishing a vacuum in a vacuum vaporization apparatus for heating one or more liquids Expired - Lifetime US3815552A (en)

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Application Number Priority Date Filing Date Title
DE19722228510 DE2228510C3 (de) 1972-06-12 Verfahren zur Erzeugung, Aufrechterhaltung oder Wiederherstellung des Vakuums im Vakuumbehälter eines nach dem Vakuumverdampfungsprinzip arbeitenden Warmwasserbereiters, sowie Einrichtung zur Durchführung des Verfahrens

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US (1) US3815552A (en(2012))
JP (1) JPS5223002B2 (en(2012))
FR (1) FR2188119A1 (en(2012))
IT (1) IT983240B (en(2012))

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3970047A (en) * 1974-03-18 1976-07-20 Stotz & Co. Ag Reduced pressure type steam generator
US5286351A (en) * 1988-12-09 1994-02-15 Terrill Designs, Inc. Water distilling method
US5947111A (en) * 1998-04-30 1999-09-07 Hudson Products Corporation Apparatus for the controlled heating of process fluids
US6062174A (en) * 1994-11-02 2000-05-16 Kabushiki Kaisha Kopuran Reduced-pressure steam heating device and method for preventing banging noise generated therein

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1987182A (en) * 1931-09-25 1935-01-08 Gasaccumulator Svenska Ab Heat exchanger
US3007457A (en) * 1958-01-27 1961-11-07 Ospelt Gustav Heating boiler
US3437078A (en) * 1967-10-10 1969-04-08 Axel B Olson Dual purpose hot water heating boilers
US3704691A (en) * 1970-03-25 1972-12-05 Willi Brandl Fuel-fired boiler for production of domestic hot water and for heating

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1987182A (en) * 1931-09-25 1935-01-08 Gasaccumulator Svenska Ab Heat exchanger
US3007457A (en) * 1958-01-27 1961-11-07 Ospelt Gustav Heating boiler
US3437078A (en) * 1967-10-10 1969-04-08 Axel B Olson Dual purpose hot water heating boilers
US3704691A (en) * 1970-03-25 1972-12-05 Willi Brandl Fuel-fired boiler for production of domestic hot water and for heating

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3970047A (en) * 1974-03-18 1976-07-20 Stotz & Co. Ag Reduced pressure type steam generator
US5286351A (en) * 1988-12-09 1994-02-15 Terrill Designs, Inc. Water distilling method
US6062174A (en) * 1994-11-02 2000-05-16 Kabushiki Kaisha Kopuran Reduced-pressure steam heating device and method for preventing banging noise generated therein
US5947111A (en) * 1998-04-30 1999-09-07 Hudson Products Corporation Apparatus for the controlled heating of process fluids

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Publication number Publication date
IT983240B (it) 1974-10-31
JPS5223002B2 (en(2012)) 1977-06-21
DE2228510A1 (de) 1974-01-10
JPS4956003A (en(2012)) 1974-05-30
DE2228510B2 (de) 1976-02-19
FR2188119A1 (en(2012)) 1974-01-18

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