NO122448B

NO122448B -

Info

Publication number: NO122448B
Application number: NO16252066A
Authority: NO
Inventors: N Fahlvik
Original assignee: Electrolux Ab
Priority date: 1965-04-09
Filing date: 1966-04-06
Publication date: 1971-06-28
Also published as: FI44835C; DE1252629B; GB1142650A; FI44835B; NL6604724A; CH453617A; SE318980B

Description

Fremgangsmåte og anordning for regulering av temperaturen i Method and device for regulating the temperature i

et dampoppvarmet apparat. a steam-heated appliance.

Oppfinnelsen vedrbrer en fremgangsmåte for å regulere temperaturen i et dampoppvarmet apparat med et behandlingsrom for gods, f.eks. et kokeapparat. The invention relates to a method for regulating the temperature in a steam-heated device with a treatment room for goods, e.g. a cooking appliance.

Oppfinnelsen angår også en anordning for fremgangsmåtens utfbrelse. The invention also relates to a device for carrying out the method.

Det er tidligere kjent ved dampoppvarmete apparater for behand-ling av gods ved temperaturer opptil 100°C å tilfore damp til apparatets behandlingsrom gjennom en tilfbrselsledning fra en ytre dampkilde, idet dampen i tilfbrselsledningen blandes med luft fra behandlingsrommet og damp-luftblandingen derefter kjoles og efter kondensering av en del av dampen tilfores behandlingsrommet, idet damp-luftblandingens kjbling reguleres i avhengighet av den bnskede oppvarmning av apparatet. It is previously known for steam-heated devices for treating goods at temperatures up to 100°C to supply steam to the device's treatment room through a supply line from an external steam source, the steam in the supply line being mixed with air from the treatment room and the steam-air mixture is then cooled and after condensation of a part of the steam is supplied to the treatment room, the cooling of the steam-air mixture being regulated depending on the desired heating of the apparatus.

Ved slike apparater må man stadig arbeide med et visst undertrykk i behandlingsrommet for å kunne suge inn tilsetningsluft og derved kunne opprettholde den tilsiktede temperatur under 100°C i behandlingsrommet. Herfor må man da med jevne mellom-rom ved hjelp av f.eks. en vannkjbler kjole bort visse varmemengder, slik at den tilforte overtrykksdamp bringes til kondensering. Dette medfbrer stort vannforbruk og også en viss uregelmessighet i temperaturkurven for behandlingsrommet. Med kjblevannet spyles også visse varmemengder bort. For det om-handlede reguleringssystem anvendes elektrisk styrte ventiler med tilhbrende pådrag og releer. I visse industrielle anlegg hvor kokeapparater av kjent type anvendes, slik som i kjott-og konserveringsfabrikker, skjer som regel rengjbring av lokaler og apparater ved vannspyling, og det har vist seg at de elektriske enheter tross innbygning og foreskrevne beskyttelsesan-ordninger blir nedfuktede og risikerer dermed å utsettes for skader som kan medfbre en unormalt kort levetid med risiko for drif t savbrytelser. With such devices, one must constantly work with a certain negative pressure in the treatment room in order to be able to suck in additional air and thereby be able to maintain the intended temperature below 100°C in the treatment room. For this reason, you must periodically use e.g. a water heater removes certain amounts of heat, so that the added overpressure steam is brought to condensation. This results in large water consumption and also a certain irregularity in the temperature curve for the treatment room. Certain amounts of heat are also flushed away with the hot water. For the regulation system in question, electrically controlled valves are used with the associated commands and relays. In certain industrial facilities where cooking appliances of a known type are used, such as in meat and canning factories, the premises and appliances are usually cleaned by water flushing, and it has been shown that the electrical units, despite being built in and prescribed protection devices, become wet and risk thus being exposed to damage that can lead to an abnormally short lifespan with the risk of operational breakdowns.

Formålet med oppfinnelsen er å eliminere de nevnte ulemper og å tilveiebringe en driftssikker og bkonomisk anordning for var-mebehandling i dampoppvarmede apparater. The purpose of the invention is to eliminate the aforementioned disadvantages and to provide a reliable and economical device for heat treatment in steam-heated appliances.

Fremgangsmåtens karakteristiske trekk fremgår av kravene 1 - lo. The method's characteristic features appear from claims 1 - lo.

Anordningens karakteristiske trekk fremgår av kravene 11 - 2o^The device's characteristic features appear from claims 11 - 2o^

I en fordelaktig utfbrelsesform av oppfinnelsen benyttes trykkluft fra trykkluftsystemet også for sirkulasjon av luft og damp gjennom behandlingsrommet og en sirkulasjonsledning. Liksom ved det tidligere kjente system bygger det nye på en sirkula- In an advantageous embodiment of the invention, compressed air from the compressed air system is also used for circulation of air and steam through the treatment room and a circulation line. As with the previously known system, the new one is based on a circular

"sjon av luftblandet damp gjennom det rom hvor den bnskede temperatur skal opprettholdes. Denne sirkulasjon tilveiebringes imidlertid ved hjelp av trykkluft, som ifblge oppfinnelsen også "sion of air-mixed steam through the room where the desired temperature is to be maintained. This circulation is, however, provided with the aid of compressed air, which according to the invention also

kan anvendes for den nbdvendige automatiske regulering av en dampventil og en termostat for denne regulering. Den tidligere nbdvendige vannavkjbling har kunnet slbyfes, da intet overskudd av damp tilfores gjennom dampventilen, hvor i stedet bare for oppvarmningen av behandlingsrommet nbdvendige dampmengder slippes frem. Armaturen for trykkluftreguleringen er meget mer ufblsom for innvirkningen av fuktighet enn elektriske systemer og kan uten risiko overspyles med vann. can be used for the necessary automatic regulation of a steam valve and a thermostat for this regulation. The previously necessary water cooling has been eliminated, as no excess of steam is supplied through the steam valve, where instead only the necessary quantities of steam are released for the heating of the treatment room. The fitting for the compressed air regulation is much more vulnerable to the effects of moisture than electrical systems and can be flushed with water without risk.

Oppfinnelsen skal i det efterfblgende beskrives nærmere under henvisning til en som eksempel valgt utfbrelsesform, illustrert skjematisk på tegningen, for å vise oppfinnelsens tilpasning, idet også andre egenskaper av oppfinnelsen vil fremgå. In the following, the invention will be described in more detail with reference to an embodiment chosen as an example, illustrated schematically in the drawing, in order to show the adaptation of the invention, as other properties of the invention will also be apparent.

Tegningen viser et skjema over ledningsfbring og regulerings-organ ved et dampoppvarmet apparat med et behandlingsrom lo, som samtidig kan være kokerom eller danne en mantel omkring et kokerom hvori behandlingen skjer. Apparatet er tilkoblet en damptilfbrselsledning 11 som er forsynt med en avstengningsven-til 12. Apparatet er også koblet til en tilfbrselsledning 13 for trykkluft, hvilken likeledes er forsynt med en avstengnings-ventil 14. Ventilene 12 og 14 kan være mekanisk sammenkoblet, slik at man med et håndgrep kan åpne eller stenge begge ventiler. I dampledningen 11 er det en motorventil 15 for regulering av gjennomstrbmningen av damp som ledes inn i en sirkulasjonsledning 16, som gjennom et sprederrbr 17 munner ut i behandlingsrommets lo nedre del, hvor sprederen 17 danner en såkalt lydlbs koker. The drawing shows a diagram of the wiring and control device for a steam-heated appliance with a treatment room, which can also be a cooking room or form a mantle around a cooking room in which the treatment takes place. The device is connected to a steam supply line 11 which is equipped with a shut-off valve 12. The device is also connected to a supply line 13 for compressed air, which is also equipped with a shut-off valve 14. The valves 12 and 14 can be mechanically connected, so that with one hand can open or close both valves. In the steam line 11, there is a motor valve 15 for regulating the flow of steam which is led into a circulation line 16, which through a spreader tube 17 opens into the lower part of the treatment room, where the spreader 17 forms a so-called sound-absorbing boiler.

Lufttilfbrselsledningen er efter avstengningsventilen 14 for-grenet i to deler, hvorav den ene 18 gjennom en reduksjonsventil 19 går til en forgrening 2o, hvorfra trykkluften dels gjennom en ledning 22 ledes til en termostat 23, som ved en impulsledning After the shut-off valve 14, the air supply line is branched into two parts, one of which 18 through a reduction valve 19 goes to a branch 2o, from which the compressed air is partly led through a line 22 to a thermostat 23, as with an impulse line

24 er forbundet med et fblsomt legeme 25, som i det viste ut-fbrelseseksempel er anbragt inne i behandlingsrommet lo. Le-gemet 25 kan imidlertid være anbragt på annet sted i systemet, hvor det reagerer ved temperaturforandringer inne i behandlingsrommet lo. Den andre grenledning 26 fra tilfbrselsledningen 13 for trykkluft går til en ejektor 27 i sirkulasjonsledningen 16, som med den andre ende er koblet til behandlingsrommets lo utlbp 28. Når trykkluft slippes frem gjennom ledningen 26, fås derfor ved en sugevirkning i ejektoren 27 en sirkulasjon av luft og damp i behandlingsrommet gjennom dette rom og sirkulasjonsledningen 16. 24 is connected to a flexible body 25, which in the shown embodiment is placed inside the treatment room 10. However, the body 25 can be placed elsewhere in the system, where it reacts to temperature changes inside the treatment room. The second branch line 26 from the supply line 13 for compressed air goes to an ejector 27 in the circulation line 16, which is connected with the other end to the treatment room's outlet 28. When compressed air is released through the line 26, a suction effect in the ejector 27 therefore results in a circulation of air and steam in the treatment room through this room and the circulation line 16.

Motorventilen 15 er normalt stengt, men åpner så snart trykkluft slippes inn gjennom ventilen 14. Under drift av apparatet reguleres motorventilens innstilling og derved dampgjennomstrbm-ningen av den temperatur som hersker i behandlingsrommet og som innvirker på det folsomme legeme 25 og dermed på den termostat 23 som regulerer motorventilen. Når ventilen 14 åpnes, strbmmer damp inn i behandlingsrommets nedre del. Samtidig blåses det inn en viss trykkluftsmengde gjennom ejektoren 27, hvilket bevirker en avsugning fra behandlingsrommet lo. Ejektoren 27 er tilpasset således i forhold til behandlingsrommets stbrrelse og bunnavlbp at det holdes et visst overtrykk i behandlingsrommet. Det kan dreie seg om o,o2 atmosfærer. For at nbdvendig temperatur skal oppnås tilfores en viss dampmengde, som proporsjoneres av den termostatstyrte motorventil 15. Det overtrykk som kommer til å herske i behandlingsrommet under drift, vil balansere ved omkring o,o5 atm. Den luft som suges gjennom ejektoren 27 blandes lengre ned i sirkulasjonsledningen 16 med den der utstrbmmende damp fra ledningen 11 og folger med inn i behandlingsrommet lo. Ved behandlingsrommets bunn er det et avlbp 29 med kondensvann-avleder og tilbakeslagsventil. Om et for stort overtrykk skulle oppstå i behandlingsrommet, avgår en viss luftmengde gjennom av-lbpet 29. Også kondensat uttas denne vei. The motor valve 15 is normally closed, but opens as soon as compressed air is admitted through the valve 14. During operation of the device, the motor valve's setting and thereby the steam flow are regulated by the temperature that prevails in the treatment room and which affects the sensitive body 25 and thus the thermostat 23 which regulates the engine valve. When the valve 14 is opened, steam flows into the lower part of the treatment room. At the same time, a certain amount of compressed air is blown in through the ejector 27, which causes suction from the treatment room. The ejector 27 is adapted in such a way in relation to the treatment room's vertical movement and bottom height that a certain overpressure is maintained in the treatment room. It can be about o,o2 atmospheres. In order for the required temperature to be achieved, a certain amount of steam is supplied, which is proportioned by the thermostatically controlled motor valve 15. The excess pressure that will prevail in the treatment room during operation will balance at around o.o5 atm. The air that is sucked through the ejector 27 is mixed further down in the circulation line 16 with the steam escaping there from the line 11 and follows it into the treatment room. At the bottom of the treatment room there is an avlbp 29 with condensation water diverter and non-return valve. If too great an overpressure should occur in the treatment room, a certain amount of air leaves through outlet 29. Condensate is also removed this way.

Om temperaturen blir for hby i behandlingsrommet lo, registrerer det fblsomme legeme 25 dette og bevirker at en avblåsningsventil i termostaten 23 suksessivt åpnes, hvorved trykket på membran-ventilen 15 reduseres, slik at ventilen stenges proporsjonalt med temperaturstigningen i behandlingsrommet lo. If the temperature becomes too high in the treatment room lo, the flexible body 25 registers this and causes a blow-off valve in the thermostat 23 to open successively, whereby the pressure on the membrane valve 15 is reduced, so that the valve is closed proportionally to the temperature increase in the treatment room lo.

I det viste system arbeider apparatet med tilfbrsel av bare så meget damp som er nbdvendig for å opprettholde den bnskede tem peratur. Det forekommer ikke noen nedkjbling av behandlingsrommet eller den tilforte damp og heller ikke noen bortledning av den tilforte varme. Apparatet arbeider hele tiden med et svakt overtrykk i behandlingsrommet, hvilket er en fordel ved koking av visse kjbttvarer. Disse får nemlig ved oppvarmningen et indre overtrykk, som ved kokerom med undertrykk kan sprenge den ytre omhylling av varene. Et ytre stbttetrykk ved damp og lufttrykket eliminerer i vesentlig grad denne risiko. En stor besparelse av vann og varmekalorier oppnås også ved oppfinnelsens tilpasning. In the system shown, the appliance works by supplying only as much steam as is necessary to maintain the desired temperature. There is no cooling down of the treatment room or the added steam, nor is there any dissipation of the added heat. The appliance works all the time with a slight overpressure in the treatment room, which is an advantage when cooking certain groceries. These get an internal excess pressure during heating, which can burst the outer casing of the goods in a cooking chamber with negative pressure. An external static pressure by steam and air pressure largely eliminates this risk. A large saving of water and heating calories is also achieved by the adaptation of the invention.

Claims

1. Procedure for regulating the temperature in a steam-heated apparatus with a treatment room for goods, e.g. a cooking appliance, characterized by the fact that, in addition to steam, compressed air is also introduced directly into the appliance's treatment room (lo).

2. Method as stated in claim 1, characterized in that steam and air are mixed with each other for introduction into the treatment room (lo).

3. Method as stated in claim 1 or 2, characterized in that temperature differences in different parts of the treatment room (lo) are equalized by causing compressed air and steam to flow through the treatment room (lo).

4. Method as stated in claim 3, characterized in that the mixture of air and steam which is supplied to the treatment room (lo) is brought to circulate through this and a circulation line (16) connected therewith.

5. Method as stated in claim 4, characterized in that the circulation of the mixture is provided by ejector action with some of the pressure media introduced into the circulation line (16).

6. Procedure as specified in any of claims 1-5, characterized in that the working media are introduced into the treatment room (lo) at its bottom.

7. Method as specified in any of claims 1-6, characterized in that the amount of added steam is regulated by means of means (15, 21, 2o, 22, 23, 24, 25) which are dependent on the temperature in the treatment room (lo), so that an adjustable temperature below the temperature of the steam at the prevailing partial pressure is maintained in the treatment room (lo).

8. Method as specified in any of claims 1-7, characterized in that the amount of compressed air supplied to the treatment room (lo) is adapted so that the temperature of the mixture is kept at the desired level during the supply of the necessary amount of steam to compensate for heat loss and heating of goods in the treatment room (lo) to the intended temperature.

9. Method as stated in some of the claims 1-8, characterized in that air is released from the treatment room (lo) to facilitate the supply of air and thus a continuous circulation.

10. Method as set forth in any of claims 1-7, characterized in that the amount of compressed air supplied to the treatment room (lo) is adapted in such a way in relation to the added amount of steam that the total pressure of the mixture in the treatment room (lo) is kept at a level that is so much higher ^ than the steam's partial pressure at the prevailing temperature, that a positive pressure is exerted on goods in the treatment room (lo) against their internal pressure under the influence of the heat input with the added steam.

11. Device for a steam-heated device, e.g. a cooking appliance, with a supply of steam and compressed air for carrying out the method according to claims 1 - lo, characterized in that supply lines (11,13) for steam and compressed air are connected to the appliance's treatment room (lo), so that these media are introduced directly in this.

12. Device as stated in claim 11, characterized in that the supply lines (11,13) are connected to each other for the inlet into the treatment room (lo).

13. Device as stated in claim 11 or 12, characterized in that the treatment room (lo) is provided with an outlet line (28) connected to this in a part opposite the circulation line (16), so that the working media must pass through the treatment room (lo) to the outlet ( 28).

14. Device as stated in claim 13, characterized by a circulation line (16) for the working media connected to the treatment room (lo), preferably its outlet (28) and inlet.

15. Device as stated in claim 14, characterized in that the circulation line (16) contains an ejector (27), by which the pressure media is introduced into the circulation.

16. Device as stated in any of claims 11-15, characterized in that the inlet for the working media to the treatment room (lo) is arranged at its bottom.

17. Device as set forth in any of claims 11-16, characterized in that the supply line (11) for steam is provided with a valve (15), which is under the influence of a thermostat (23) with a thermal body (25) depending on the temperature in the treatment room (lo).

18. Device as specified in any of claims 11-17, characterized in that the supply line (13) for compressed air to the treatment room (lo) is provided with a valve (14), which can be set to such a value that the total pressure in the treatment room (lo) is kept at a higher value than the internal pressure in the goods in the treatment room (lo) at the simultaneously prevailing temperature in it under the influence of the heat supply from the added steam.

19. Device as stated in claim 18, characterized in that the valve (15) in the steam supply line (11) is designed as a valve controlled by the thermostat (23) with compressed air.

20. Device as specified in any of claims 11-19, characterized in that the treatment room (lo) is provided with an air outlet (29) with a steam trap.