US2473095A

US2473095A - Tilting salt bath furnace

Info

Publication number: US2473095A
Application number: US624691A
Authority: US
Inventors: Grene George Henry Stanley
Original assignee: Wild Barfield Electric Furnaces Ltd
Current assignee: Wild Barfield Electric Furnaces Ltd
Priority date: 1944-11-01
Filing date: 1945-10-26
Publication date: 1949-06-14
Anticipated expiration: 1966-06-14

Description

June 14 1949.

\ TILTING SALT BATH FURNACE Filed 001?. 26, 1945 5.409 zz Z01 G. H. s GRENE 2,473,095

4 Sheets- Sheet 1 June 14, 1949. e. H. s. GRENE 2,473,095

TILTING SALT BATH FURNACE Filed Oct. 26, 1945 4 Sheets-Sheet 2 flag/4.2 07 G'eazzze 29 5 G'r June 14, 1949. s, GRENE 2,473,095

TILTING SALT BATH FURNACE Filed Oct. 26, 1945 4 Shets-Sheet 3 FIG 4 Georgeiz'emySianlcyGrene Patented June 14, 1949 ..,2,473, 085 "ZTIIiTING'SALT BATH'FURNACE Greorgeiilienry. Stanley Grene; Watford,t'En'gland,

rassjgnm mf one-half to.-Wild,-Barfielcl;

aLimited, Watford, Hertfordshire,

Furnaces ..,Eng-land i Application-"October 26, 1

Electric in Great Britain November 1,1944

.--6, Claims. 1

It. is ordinary-2 practice tofaztilt: melting-furnaces where thereis ax-moltenychargewhichi can'so'v be poured. -.jSa'lt bath furnacesr.are,:however,cused forthe treatment-bf solid workslpiecesvand it does not appear to have hitherto to arrangeihfor remowal :of the work by usual ..metho,ds.. andito. .tilt .the. furnaceawhen the. salt is to be removed for cleaning,.outltherbath or to provide readily for substitution of another salt for a diiferent process.

The rpresent inventiomprovides a tiltableasalt bath: furnace, enabling this eprocedurerto ebe --readily carried out, and so-otoefiacilitate what is .otherwise. a laborious job of bailing outithe molten -salt--t enable the accumulation; of sludges-at the;

.bottom tobe removed.

In. the: preferred forms thervtiltableubath is readily removable; in cases where thaamount of -work-to becarried out justifiesit, separate :baths can thusibe used for the several saltsiandtheo rbaths can be changed so that contaminatiomdue to residual salt in the brickwork does not take place. The'--b'ath--with its electrodes can be immediately lifted from therbearings and another -droppedirr place.

- The above and other;:-par-ts ;vof theninvention are embodied in atypiealsform illustnated'qby the accompanying drawings in which Fig. 1 is a front elevation,

Fig. 2 is a side elevation,

Fig. 3 is a plan,

Fig. 4 is a fragmentary sectional elevation, showing the bath structure and associated parts in working position, and

Fig. 5 is a similar view showing the workpiece removed, and the parts in position for pouring and. collecting the salt.

The furnace comprises a body portion I which houses the conventional electrical gear, enclosing a contactor and isolator indicated at 2, step-down transformer at 3, controllable bi-metallic strip energy regulator at 4, amrneter 5 and indicator lamps 6, tapping switch 1 for the transformer with hand wheel 1a and knife switch elements 8. The main isolator switch handle 9 is at the back and a push-button type emergency stop switch ID in front. The body portion I has a pair of forwardly projecting side wings or brackets II, with elements ll of the rotary supports for the bath arranged to receive the complementary elements or trunnions I3 on the bath M. A removable mould I5 to receive the salt is connected with the bath by a, channel [4, so that when the bath' is tilted the salt can be carried on the front of the bath and may have a serrated or other apoccurred to anyone .propriatevsurface:"l5a on which the salt' will lie wz-as {it solidifies, so facilitatingbreakingit upwfor -;use again. The electricalleadsbetween the body portion 2 and the bath arereadily detachable for removal -of thebath and as shown include knife .blades l6 adaptedwto engage thefixed elements #8 whichare connectedto the electrodes l'lizSO :thatthe electrical connection wis: automatically rbroken whenxthegbathistilted. or removed. A -10.-,

cover .18 carried by the-back. of the: bath encloses the; electrical;lconnectionsawhen :the bath is fill its normal'uprightposition.

The use of the bathandythe deliveryof-the salt; from-,.-the.bath to the-removablemold "i5 is .is shown-in its normal --working.- positionwith a wworkpiece 28 best ashownin; Figs.- 4; and. 5. "In Fig-.- 4 the bath suspended from-the branch 23 .of

-.;the'tool post 22 fortreatment-in the-.molten salt -ralso=beemployed as; a tiltingr-lever. When the On .the.-other hand Fig. 5 shows the bath tilted as by tilting. the tool post 22-=-which may -bath-is tilted the molten-fsa'lt is conveyed by-the wchannel passage l4 to thermold @and solidified after which it may be readily removedfor recoveryof the-salt. -It. is to-be. noted that the electric circuit to the electrodes is broken at ,the beginning hot the tilting movement. by the swinging of the switch blades l6 from the switch elements 8.

The bath is covered by a hood I9 with lugs 20 which centre it on the bath. The hood is provided with an observation window 2| that is preferably covered by a wire mesh or perforated metal sheet or the window may be formed by juxtaposed perforations in the sheeting forming the hood, In addition, the hood is provided with a relatively small central aperture 2| for the admission of the work piece 28'. The opening 2! is relatively small and centrally located and the window 2| is covered by a mesh or the like to protect the operator from splashes.

The work is placed or suspended in the bath and removed after treatment in any normal or convenient way. As shown, a tool post 22 with a work suspension branch 23 is remova-bly supported in a socket 24. The tool post or a separate lever can be inserted in the socket 25 on the side of the bath to tilt the bath when required. A portable pyrometer 2 B is shown, carried when not in use in a further socket 21 in one of the wings.

In many cases it is convenient to provide a series of adjacent salt baths for successive stages of a process; for example one or more preheating baths, a hardening bath, a quenching bath, and possibly a further bath for secondary hardening.

The wings or brackets of the improved furnaces can readily be arranged to be bolted or otherwise attached against those of adjacent furnaces, so as to constitute a fixed battery of successive baths along which the work under treatment can be progressed. Bolt holes 28 are shown for this purpose.

I claim:

1. An electrode salt bath furnace to treat solid work pieces including a bath having an open top, means for carrying solid work pieces in the bath by suspension from above the open top of the bath, means for tilting the bath, electrodes for heating the bath mounted in the bath, electrode contact making and breaking means for making contact when the bath is in normal position and breaking contact when the bath is tilted, and means separably attached to the bath for receiving the whole of the salt from the bath when the bath is tilted.

2. An electrode salt bath furnace to treat solid work pieces including a bath having an open top, means for carrying solid work pieces in the bath bysuspension from above the open top of the bath, means for tilting the bath, means separably attached to the bath for receiving the whole of the salt when the bath is tilted, electrodes for heating the bath mounted in the bath, means for removably supporting the bath with its electrodes on the furnace, and electrode contact making and breaking means for making contact when the bath is in normal position and breaking contact when the bath is tilted or removed.

3. An electrode salt bath furnace to treat solid work pieces, means for carrying the bath tiltably and removably, means for introducing and removing work pieces into and from the bath, electrodes for heating the bath, means for tilting the bath to deliver the salt from its effective position in the bath, removable means carried by the bath for receiving the salt delivered from the tilted bath, and electrode contact making and breaking means for making contact when the bath is in normal position and automatically breaking contact when the bath is tilted or removed.

4. A construction as defined in claim 3 wherein the means for receiving the salt upon the tilting of the bath is formed with a serrated surface for forming a complementary surface to the salt solidifying thereagainst.

5. A salt bath furnace for treating solid work pieces and having spaced electrodes, means for supplying said electrodes with electric current, means for tilting the bath with the electrodes, a removable mould carried by the bath, and passage means connecting the mold with the bath for passing to the mold the whole of the salt from the bath as the bath is tilted.

6. A salt bath furnace for treating solid work pieces and having spaced electrodes, means for supplying said electrodes with electric current, removable cover means attached to and overlying the bath, an observation window in said cover, a work admitting opening in said cover, means for tilting the bath, a removable mould carried by the bath and receiving the whole of the salt from the bath as the bath is tilted, and contact elements located under the cover means and controlling the current through the electrodes.

GEORGE HENRY STANLEY GRENE.

REFERENCES CITED The following referen'ces are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date Re. 16,054 Moore Apr. 28, 1925 696,004 Burton Mar. 25, 1902 749,403 Rousseau Jan. 12, 1904 863,469 Thill et al Aug. 13, 1907 1,032,217 Johnson July 9, 1912 1,070,568 Wile Aug. 9, 1913 1,370,989 Nye Mar. 8, 1921 1,601,703 Patterson Sept. 28, 1926 2,367,897 Smith 1. Jan. 23, 1945 2,379,651 Pritchard July 3, 1945 FOREIGN PATENTS Number Country Date 27,836 Great Britain Dec. 11, 1912 24,850 Great Britain June 25, 1914 291,450 Great Britain May 2, 1929