US1798678A - Electric furnace - Google Patents

Electric furnace Download PDF

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Publication number
US1798678A
US1798678A US200197A US20019727A US1798678A US 1798678 A US1798678 A US 1798678A US 200197 A US200197 A US 200197A US 20019727 A US20019727 A US 20019727A US 1798678 A US1798678 A US 1798678A
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US
United States
Prior art keywords
furnace
switch
temperature
charge
resistor
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US200197A
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English (en)
Inventor
Keller Gottlieb
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
BBC Brown Boveri AG Germany
Original Assignee
Bbc Brown Boveri & Cie
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Filing date
Publication date
Application filed by Bbc Brown Boveri & Cie filed Critical Bbc Brown Boveri & Cie
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Publication of US1798678A publication Critical patent/US1798678A/en
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    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
    • G05D23/00—Control of temperature
    • G05D23/19—Control of temperature characterised by the use of electric means
    • G05D23/20—Control of temperature characterised by the use of electric means with sensing elements having variation of electric or magnetic properties with change of temperature
    • G05D23/22—Control of temperature characterised by the use of electric means with sensing elements having variation of electric or magnetic properties with change of temperature the sensing element being a thermocouple
    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
    • G05D23/00—Control of temperature
    • G05D23/19—Control of temperature characterised by the use of electric means
    • G05D23/1927—Control of temperature characterised by the use of electric means using a plurality of sensors
    • G05D23/193—Control of temperature characterised by the use of electric means using a plurality of sensors sensing the temperaure in different places in thermal relationship with one or more spaces
    • G05D23/1931—Control of temperature characterised by the use of electric means using a plurality of sensors sensing the temperaure in different places in thermal relationship with one or more spaces to control the temperature of one space

Definitions

  • Fllliis invention relates s e llas among its obglects of tlie resistor typ l c improvements in the construction andcp ⁇ r ation oit suoli furnaces. According; e
  • Fin, 2 is a curve diagram illustrating ltice temperature conditions during the furnace operation and 3 is a View similar to Fig. 1, illustrat- 'ing another form of the invention ln the operation of electric furnaces of the resistor type, such as are used ⁇ iter heat treatment, etc., the electrical input must be'go'verned by the maximum allowable surface v'temperature of the charge, by the timerequired to bring up the entire body of thev charge to the desired temperature, and by the soakingl period during which the charge is desired to be maintained at a particular temperature.
  • the periodical disconnection and reconnection of large powenconsurning apparatus means also a succession .of peek loads on the electrical supply line ci ylie furnace. This 'has not only a liiglnly project-,turbingga iniluenceon the remaining load connected the line, such as lights, but yery often reacts unlavorably on the power station itself, .'Wnicli, in many instances, penalizes consumershaying such periodically Varying power demands.
  • the 'power input et everyv instant is maintains@ sensi or epprorirneteiy equai te the -snrn oi the fnrnece iosses anni the errase oi' energy which iows into the interior oi: the charge when the surface terne persture is et the maximum permissible veine.
  • hee-ting elements are .connected either in richte ⁇ or in star; ne ad- Lreepere a. charge l1, that is to be treated.
  • a peil' of pyrometer elements u enci o, in the form of thermo-'couples are errsngeci to respond to the temperature at the surface of the charge and in the interior thereof, respectiveiy.
  • the resistors Ai, etcw El, etcL, are arranged to. be supplied from threephese bus-bers l2 that may be connected. through e main circuit breaker i3 to e. poiynhsse snpniy line i4.
  • the circuit breaker is errengesi to be ectuete; by operating eoii l5;
  • the resistors the heating group are srrengeri to be controiiefi by ineens ci a, three-pcie cubie-throw switch 2i emi rney be connecteci her in site scross the bus-bers 1Q by throwing the switch 2l to the tops or in ster by throwing 'the switch down The switch 2li.
  • the resistor eieinents er the second group and the hns-bers serves to oie-energize or energize sei group 7Ehe sctnsting coii switch 2S is arranged to' be cioseci or opened i byrneens @sir of actuating coiis 29 enoi 29
  • the switches 2i, 23 and 28 are controilel by the sbove rnentioneri thermo-coupies u end e in orcier to secure within the ifnrnece and the charge the ciesireci temperature conditions.
  • each of the thermo-cow pies u, e operates e regnieting device i7, respectiwiy7 which in turn controis the operetion oi the ser/crei switches through relays Si? 32,33,
  • the reguieting device has e mor/:ibis Contact erin 'Ui moved in accordance with the eiect oi the temperature on the outer thermo-coupie e; end three contact members u2, 'm3, wi, for energizing reieys 317 327 and the cut-out eoii 29 of the fiisconnecting switch 28 of the second resistor group respectively, the energy for seioi reieys andcoii being supplied ⁇ ironi the secondary winding of an auxiliary transformer 35.
  • the regulating device V has e. movable contact arm Vl actuete in accordance with the temperature ci: the internati thermo-Connie v and three Contact members e2, e3, 114.-, for energizing the closing coil 29 or the disconnecting switch 28, the cut-out coii 2W of seid switch and the relay 33, respectiveiy.
  • the latter reieys when ciosed, estebiishes e circuit for energizing the cut-out coii 15 of the main switch 13, thereby isconnecting the supply from the furnace.
  • thermo-couple o .connected to the regulator 42.
  • the switch 43 for connecting the induction motor regulating device 42 to the thermo-couple o is operated loy an actuating coil 45 which 1s energized by the relay 3l when the resistor group A is connected in star, .an additional switch 46 being included in the energizing circuit of said coil Li5 in order to permit the action oi the induction regulator to be cut od at will.
  • the induction regulator is directly under control of the internal temperature of rthe charge from the moment the resistor group A is connected in star.
  • the induction regulator will boost the voltage, gradually reducing the voltage as the temperatur-e of the interior approximates the external 'temperature.
  • the induction regulator will automatically reduce the voltage to preventf'such rise.
  • the rarious switches, relays, etc. have heen indicated diagrammatically, as the precise structures oi the relays and switches, do not constitute the suioj'ect matter ci the present invention and anytype ci switches or relays that will operate in the way described above may loe used in a way familiar to those skilled in the arto
  • the gradual variation of the power supplyin accordance with the operation oi each thermo-couple, lay controlling a suitably connected induction regulator may also be embodied in an arrangement wherein the induction regulator is under control both of the internal aswell as .ci the external thermocouple.
  • the alcove described system of furnace regulation lends itself also for partial application, that is, for comhination with systems 'ci the type used heretofore, that is, combination oi continuous and automatic power regulation with intermittent power supply.
  • the heating process energy may he supplied gaocere tinuously with gradual or step-loystep decrease ci" the power input until the internal temperature has reachedthe limiting value. Thereafter the power supply is controlled hy intermittently cutting od the power to maintain the desired temperature.
  • FIG. 3 oi' A somewhat modiiied forni of the invention is shown in Figure 3 oi' the drawing.
  • rlhe furnace is arranged similar to Figure l.
  • the two three-phase resistor groups A and B of the furnace are controlled by "four threepole double-throw switches LK, L, lli, li', having switching members lil, K2, Ll, L2, L3, Ml, M2, M3, lll, N2, N3, and correspondingly marked contact members K1",K2, etc., respectively.
  • Switch 2K may be thrown upwardly by energizing the actuating coil lc or downwardly 1oy energizing the actuating coil ls.
  • The'sv/vitches lli, M, N inay he similarly controlled loy energizing the actuating coils ZI) ZIP? mi? .m/ 9%?? nl.
  • both resistor groups By throwing the switches K and L downward and switches ld and N upward, both resistor groups .spend B vare connected in delta. By leaving the switches K and L unchanged lout throwing the switches M and N downward,the two groups are connected in star, the second group B having an induction regulator l connected in the star point. ln
  • the next control position the switches K andv L are thrown 'upward' thereby connecting the corresponding resistor elements of groups A and id in series.
  • the centrelly-connected resistor elements may loe operated either in delta when the switch hl is thrown upward, or in star with the induction regulator in 'the star point lwhen said switch N is 'thrown downward.
  • induction regulator may loe used to hoest the Voltage or to hucl the Voltage and is operatedhy a motor 5l which is' controlled from a suitable regulator 52 in accordance with the condition oi the thermocouples n or c, ein amplier 53 is connected,

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Automation & Control Theory (AREA)
  • Remote Sensing (AREA)
  • Control Of Temperature (AREA)
US200197A 1926-06-23 1927-06-20 Electric furnace Expired - Lifetime US1798678A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE1798678X 1926-06-23
DE636414X 1926-06-23

Publications (1)

Publication Number Publication Date
US1798678A true US1798678A (en) 1931-03-31

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ID=62043960

Family Applications (1)

Application Number Title Priority Date Filing Date
US200197A Expired - Lifetime US1798678A (en) 1926-06-23 1927-06-20 Electric furnace

Country Status (2)

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US (1) US1798678A (fr)
FR (1) FR636414A (fr)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2508382A (en) * 1946-10-10 1950-05-23 Armstrong Cork Co Method and apparatus for dielectric heating
US2557905A (en) * 1946-09-06 1951-06-19 Budd Co Electric heating control
US2568411A (en) * 1949-03-09 1951-09-18 Westinghouse Electric Corp Electric heating system
US2634360A (en) * 1950-09-21 1953-04-07 Standard Oil Co Analytical apparatus for determination of sulfur
US2678959A (en) * 1952-10-07 1954-05-18 Bell Telephone Labor Inc Temperature-controlled induction furnace
US2780710A (en) * 1952-05-03 1957-02-05 Dunlop Rubber Co Apparatus for regulating the temperature of electrically heated elements
US2832879A (en) * 1954-07-29 1958-04-29 Jurian W Van Riper Temperature control mechanism for extrusion apparatus
US3094604A (en) * 1960-08-12 1963-06-18 Pullman Inc Vehicle electric heating system
US3159736A (en) * 1962-07-20 1964-12-01 Portland Copper & Tank Works I Control circuit for electric furnace
US20120314728A1 (en) * 2011-06-08 2012-12-13 Warner Power Llc System and method to deliver and control power to an arc furnace

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2557905A (en) * 1946-09-06 1951-06-19 Budd Co Electric heating control
US2508382A (en) * 1946-10-10 1950-05-23 Armstrong Cork Co Method and apparatus for dielectric heating
US2568411A (en) * 1949-03-09 1951-09-18 Westinghouse Electric Corp Electric heating system
US2634360A (en) * 1950-09-21 1953-04-07 Standard Oil Co Analytical apparatus for determination of sulfur
US2780710A (en) * 1952-05-03 1957-02-05 Dunlop Rubber Co Apparatus for regulating the temperature of electrically heated elements
US2678959A (en) * 1952-10-07 1954-05-18 Bell Telephone Labor Inc Temperature-controlled induction furnace
US2832879A (en) * 1954-07-29 1958-04-29 Jurian W Van Riper Temperature control mechanism for extrusion apparatus
US3094604A (en) * 1960-08-12 1963-06-18 Pullman Inc Vehicle electric heating system
US3159736A (en) * 1962-07-20 1964-12-01 Portland Copper & Tank Works I Control circuit for electric furnace
US20120314728A1 (en) * 2011-06-08 2012-12-13 Warner Power Llc System and method to deliver and control power to an arc furnace

Also Published As

Publication number Publication date
FR636414A (fr) 1928-04-10

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