US1532502A - Electric heater - Google Patents

Description

J. L LAWRENCE ELECTRIC HEATER F'lled Aug. 15, 1922 April 7, 1925.

/NVENTOP JOSEPH L A WRENCE. BY

A TTOP/V VS.

Patented pr. 7, 1925..

UNITED STATES PATENT omer.;

v.Iosnrn L .,LAWRRNCR, or SAN IRaNcIysco, oaLIreRNre nssIeNoR To HERZOG ELEG- VvTRIO @a ENGINEERING contraria?, or saN rRnNcIsco, CALIFORNIA, a oo RroRn- VTIoN `,or oaLIroRNIA.

ELECTRIC HEATER.

T 0 all 'whom 'it may concern:

Be it known that 1, JOSEPH L. LAWRENCE, a citizen ofthe United States, residing Lat the city Vand county oit San Francisco and State ot Galiforniznhave invented new and usefulimprovements in Electric Heaters, ot which the kfollowing is a specification.

` This inventionrelates to electric heaters and especially to portable heaters such as employed in heating` individual rooms in residences, etc., as distinguished trom electric cookers, toasters and the like.

` Electric heaters, as generally designed, convert electric venergy into heat by passing the current-or energy to a conductor having sufficient resistance to produce a sired 'or` predetermined temperature. yThe heat thus produced isin some instances projected by reflectors, 'and in'other instances by direct radiation and conduction, and again, by kair circulation "by the heatpro- .duced is in most cases so localized that the effect oftheheater is only noticeable in the immediate vicinity. 1

The objectoiz the presentrinvention is to generally improve and simplify electric heaters, and especially that type inl which air circulation sought;l to provide large heating surfaces which will permit eiicient radiation and conduction, and to provide a novel arrangement of the heating elements with relation tov their supports and surrounding casing, whereby efficient circulation and distribution of the heated air will be obtained. Further objects willl lhereinaiter appear. A

The invention consists of the parts and the construction, combination` and arrangement of parts as' hereinafter more fully described and claimed, having reference to the; accompanying drawings, in whieh Fig. 1 is a central, vertical, longitudinal section '01 the heater.

Fig. 2 is a plan view of the same. f

Referring to the drawings in det-ail, A indicates a. base member consisting of a rectangular shaped plate 2 provided with supporting legs'. Supported bythe base or plate 2 is a rectangular shaped exterior sheet metal casing 4,' andv supported by the de-V Application `filed August 15, 1922. Serial No. 581,951.

casingin turn is a top plate 1B, .which coinprises of a rectangular shaped frame section i having a downwardly turnedflange 6 and a pair ot cross hars 7. A pair otendopenenge 8 is thus formed inthe plate and a central opening 9." rlhe v.side sections ot rvthe iranie are slightly increased in ,width as indicatedat 1U, and they cooperate with the cross bars 7 to itorm an inner frame to which is attached a rectangular shaped casing v11; said casing being secured to the upper frame plate by means of' a bottoni plate 12 and tie y rods 13. Mounted interior of the casing section 11, and disposed concentric therewith and interspaced therefrom, is a pair oil inner casing sections 14e-and 1,5. These casings aresupported entirely by the lower plate 12through means ot legs orupright bolts as indicated at 16. In other words direct contact between the lower ends ot the inner casing . sections 14 and 15 issnot made with the bottom plate 12 as a spacing, such as shown at 17, isdesired to permit a slight circulation of airA for purposes hereinafter to be described. The upper end .ot the innermost casing indicated at 15 is flanged to form a frame as at 18, and this is covered with a wire mesh or screen 19; the-openings 8 at the respective ends thereof being ysimilarly covered with screens vas shown at.2().

rlphe heating elements employed are disposed within the inner casing 15 as shown in Figs. 1 and 2. The-y are supported by .a central rod 21 anda cro-ss arm 22. The

'elements employed may heef any suitable character, but consist preferably of nichro-me wire wound Vabout lava spools or sleeves such as indicated at.23. The spools or sleeves carrying the windings` are hung 'from the cross bar 22 by attaching the upper termina-ls of the winding thereto, andthe lowver ends or terminals of' the windings. are

the heating elements or the windinvs carried by the sleeves 23 in any suitable manner, but these windings, together with the lava sleeves supporting the same, will within a very short time assume a red hot temperature. The heat produced is thrown ott' by radiation and the. surrounding air contained in the innermost 'casing 15 is thereby heated and discharges upwardly through the screen 19. A slightly evacuated condition is produced in the lower end of the casing and an in rush of air will thus take place from the lower chamber indicated at 30, which is in communication with the atmosphere through the screen covered openings 8. 1n other words the moment circulation is started air will enter the screens in the direction of the arrows, see Fig. 1; it will then pass through the lower chamber in the direction of the arrows, and will finally discharge upwardly through the innermost casing 15 and escape through the screen 19.' Eiiicient circulation is in this manner maintained and large volumes of heated air will constantly be discharged. The air will not only be heated by radiation, but also by direct contact with the windings and by passing through the interior of the spools or sleeves supporting the same as the lava spools assume substantially the same temperature as the windings supported thereby. A large heating surface is in this manner produced whereby direct contact with the air is permitted, and whereby a large radiating surface is also maintained. This radiation will heat the exposed surfaces of the innermost casing 15 and this will again heat the air by radiation and conduction. rhis heat should be restricted to the innermostcasing and the heating clements proper as interference with efi'icient circulation of air would otherwise be produced. For instance if any of the heat should be conducted or radiated to such an extent as to heat the casing 11, then a Ynt upward current would be started in the ve"- tical passages communicating with the openings 8 and practically no circulation of air would take place, but such heating of the casing 11 is prevented due to the fact that the casings 11, 14 and 15 are interspaeed and dead air spaces l!) and lll are formedbetwee'n the same. If the air in these spaces has any tendency to heat, a slight upward circulation will take place as air can enter these spaces through the lower annular opening 17. lThe screens indicated at 19 and 2O are merely employed for the purpose of excluding paper particles or to prevent other articles from accidentally entering the casing of the heater, for instance an object dropped through the opening 19 might do considerable damage, particularly if one or another of the heating elements should be encountered, and it is for this reason that the openings employed are screened.

ldfhile certain features of the present invention are more or less specifically illustrated, wish it. understood that various changes in form and proportion may be rei sorted to within the scope of the appended claims, similarly that the materials and finish of the several parts employed may be such as the experience and judgment of the manufacturer may dictate or various uses may demand.

Having thus described my invention, what l claim and desire to secure by Letters Patent is 1. An electric heater, comprising a casing a. base plate therefor and forming ay closure lfor the lower end thereof, a top plate carried by the casing having air inlet and discharge openings formed therein, a casing attached to the top plate and interspaced with relaL tion to the base plate, said casing communieating with the discharge lopening at its upper end and with the inlet openings at its lower end, a` flange secured to the lower end of said last named easing, a second casing supported by the flange and interspaced with relation thereto to form a dead air space, and an electric heating element disposed within said second named casing.

2. An electric heater comprising a casing, a base plate therefor and forming a closure for the lower end thereof, a top plate carried by the casing and having air inlet and discharge openings formed therein, a. casing attached to the top plate and interspaced with relation to the base plate, said casing communicating with the discharge opening at its upper end and with the inlet openings at its lower end, a flange secured to the lower end of said last named casing, a pair of interspaced casings supported by the flange and interspaced therefrom, and an electric heating element disposed within the innermost of said last named casings.

3. An electric heater comprising a rectangular shaped casing, a base plate forming a support and a closure for the lower end thereof, a pair of air inlet openings formed at each end of said plate and al eentrail air discharge opening also formed in said plate between the inlet openings, a rectangularl shaped casing supported by the top plate communicating at its upper end with the air discharge opening and at its lower end with the air inlet openings, a rectangular shaped bottom plate attached to the lower end of said casing, a rectangular shaped casing supported by said bottom plate and disposed within the second named casing and interspaced with relation thereto and an electric heating clement disposed within the innermost of said last named casings.

4. In a heater of the character described the combination with the imieimost easing and the base plate, of a. vertically'disposed rod supported by the base plate, a cifoss arm on the upper end of Saifi rod, pair of eieotrieal heating elements Suspended one from each end of said arm, a pair of rods disposed n alignment with each of said heating elements and Connected with said heating elements, and means for oi'ming a eil."- cuit through the central rod and the last named rods to permit the passage of a ouri'ent through the respective heating elements.

JOSEPH L. LAWRENCE.

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