US1821832A

US1821832A - Hardening furnace with continuously operating charging device

Info

Publication number: US1821832A
Application number: US350769A
Authority: US
Inventors: Goerig Ernst; Lindhorst Heinrich
Original assignee: Individual
Current assignee: Individual
Priority date: 1928-12-18
Filing date: 1929-03-28
Publication date: 1931-09-01
Anticipated expiration: 1948-09-01

Description

Sept. 1, 1931. E. GOERIG :TAL A 1,821,832.

HARDENING FURNACE WITH CONTINUOUSLY OPERATING CHARGING DEVICE Filed March 28, 1929 Patented sept. 1, 1931v ERNST. Gonnie, or MANNnnIlvLANn Hummel-r, nINnHoi-tsr, orYBnRLIN, GERMANY y HARDENING summon warn Generique-.Usar ernnamrne' cnnnema nnvrcnA Application med March ze, 192e, serial No. strives,` and in Germany December 1e, 192s.

The present invention relates toV a hardening furnace, which is especially suited for the hardening of large quantities of products and in which acementing` powder is used of which only relatively small amounts are introduced into the furnace. The essential part of this powder will gasify and the developed hot gases under Vpressure'will eifect the hardening action.

In such furnaces it is'` advantageous to add Vthe cementing powder slowly and by degrees into the hardening space so that the hardening gas is developed gradually, and in most cases it is necessary to replenish the cementing powder in the lfurnace several times `during the hardening process. The slow addition of the powder must occur without opening the drum, because it is ofV utmost importance that the hot gas under its elevated pres-L sure does not escape, and that the pressure or temperature of the same is not lowered. It is further necessary that the'powder charging device* operate accurately,rso that 'the yamount ofpowder necessary for the treatment of a. furnace charge is added to the furnace in portions of exactly the same weight and at regular time intervals. Above all great care must be taken to prevent the powder feeding'device'from becoming clogged. The cementing powder is frequent-lv moist vand during the I.Q'asiiication steam isf often formed, which penetrates into the powder storing tank. wherebv the percentage of moisture in the same is increased. Thereby the powder in the tank will be converted into a cloddv mass, which will block up the tank and the discharge conduit therefor.

According to the present invention the above mentioned drawbacks are eliminated by means of a powder tank of specialform which cooperates withy suitable feeding devices.

The invention is shown bv way of example in the accompanying `drawings in which Fig. l is a sectional view of a preferred embodiment ofthe invention. p c

Figs. 2 and 3 show details of two modifications'of the scraper. Y

I According to Fig. l the greater part of the feeding tube 2v for the cementing agent Vof its own weight.

is arranged inside of the hardening drum l, which isheated in-known manner.` In the tube 2 and rigidly connected to the samea screw conveyor 3 is located, which loosely -surrounds the pyrometer tube 4, so that the tube 2 and the conveyor?) may be rotated relatively to the pyrometer tube 4. This tube is fastened in the tlange-like body 5, preferably lby means such as welding. Opposite to the body 5 a bearingv22lisarranged, which supports one end of the tube 2 and in which the tube maybe rotated by means such as the worm wheel 6. The icernenting powder is stored in a container 8, and jis delivered to 1 the vconveyor 'through a; channel 9. The

velocity of rotation of the conveyor can be controlled and adjusted by ymeans' of arrangements known per se and in this way the amount ofvrpowder, which is fed at Vany timev of the feeding device may according tothe Y invention be prevented by means of the sim ple andeicient device described below. l

Y Thepowd er tanks hitherto used were usually hopper-shaped. AccordimgV to thel present p invention the powder container consists of a vertically arranged truncated ,cone of upwardly decreasing width, so that the walls of vthe containerwill offer no'resistance to the powder which is dropping downward because lIn order to vfacilitate the emptying'of the container the bottom of the same is inclined towards the outlet channel 9 which forms a direct continuation of the said bottom. This arrangement will be suiicient to prevent a baking of the powder, providedr that the same is in a relatively dry state.

t The disintegration Vof the cementing powder eifected by giving the container a special shape. in order to prevent the outlet conduit .being blocked, may be further. increased b v preheatinn the powder. o In this case the heating gases from the fire chamber of the furnace may be utilized. they being passed through a heating coil l0 arranged in the container 8. Other heating fluids may be passed through the heating coil, for instance het water or the like.

Instead of the above described heating device or together with the saine the following arrangement may be employed:

A shaft 15 is vertically arranged in the powder container and rotates in the bearings 11. The shaft 15 is operated from the saine driving arrangement as the worm wheel 6 or directly from this wheel. Also another source of driving force may be employed and in this case the shaft may be rotated from the driving gear 12 by means of the shaft 13 and the bevel gears 14. The gears 14 are surrounded by a protective cover 19. At the lower end of the shaft 15 a scraper 16 is fastened which rotates together with the shaft and feeds the powder through lthe channel 9 tothe conveyor 3. As shown in Fig. 2 the scraper or propeller 16 is bent horizontally in such manner that the points of the same project in the direction of rotation, so that the powder caught by the propeller will be forcedtowards the middle part of the scraper, that` is, towards the conduit 9. The wings of the scraper are further bent vertically in such manner that the front edge a when seen in the direction of rotation assumes a raised position, whereas the rear edge b is lowered. The propeller 16 will therefore notonly guide the powder towardsthe channel 9, but also press it into the saine, whereby the channel cannot be blocked. The scraper may also consist of two different coacting elements and a device of the-kind is shown in Fig. 3. According to this figure a member 20 is employed having the forni of a double wing the points of which are bent forward `in the direction of rotation. This membery cooperates with a propeller 21, the wings of which may he relatively short, because the purpose ofthe saine is merely to press the cementing powder through the channel 9. The scraper arranged directly above the channel 9 and the middle par-t of 'the saine widened, partly because the stress isv greatest in this part and partly in order to cover the channel 9 see also Fig. 2) to prevent the powder dropping down into the saine when the machine is at rest. Through this arrangement a special closing' device for .the channel 9 is made superfluous.' Y

In case the powder should be very moist ,a cross rod, or two oppositely located cross rods 17 may be arranged above the scraper or may he employed. in its stead. These rods `are fastened to the shaft 15 and may be equipped with vertically arranged pins 18, whereby double ralres are formed. Through `this device the` powder will be thoroughly rstirred and the'balring of the same will be prevented. The device of Fig. 3 differs somewhat from that of Fig. 2, in that two plates `20 and 21 are provided, arranged approximately 90o apart on the central shaft 15. The plate 21 of the device of Fig. 3 is shown as having rearward or trailing, convex surfaces b, and front or leading concave surfaces a.

We claim:

1. In a hardening furnace with continuously operating charging device, a container for cementing powder having a vertical axis and having the forni of a truncated cone, the cross-section of which decreases in upward direction, the container also converging slightly at its bottom, a device for conveying the cementing powder into the furnace, and a comparatively narrow channel connecting the said container with the said conveying dev-ice.

2. In a hardening furnace with continuously operating charging device, a container for cenienting powder having a vertical axis and having the forni of a truncated cone, the

cross-section of which decreases in .upward direction, a device for conveying the cementing powder into the furnace, a comparatively `narrow channel opening into the said con- .tainer and connecting the same with the conveyor device and a bot-tom inthe container inclining towards the entrance tothe said channel.

3. In a hardening furnace with continu-- ously operating charging device, a container for cementing powder having avertical axis and having the form of a truncated cone, the cross-section of which decreases in upward direction, a device for conveying the cementing. powder inte the furnace, a channel opening into the said container and connecting the saine with the conveyor device, a bottom in the container inclining downwardly towards the entrance t-o the said channel and' a heating device arranged on the inside of the said container.

4. In a hardening furnace with continuously operating charging device, a container for ceinenting powder having a vertical axis and having the form of a truncated cone, the cross-section of which decreases in upward direction.` a device for conveying the cementing powder into the furnace, comprising a tube of uniform diameter and a screw conveyor which is Vrigidly connected to the inner surface of said tube, a channel opening into the said container and connecting the "saine with the conveyor device, a bottom in the container inclining downwardly towards the entrance to the said channel and means for moving the powder towards the said channel entrance.

5. In a hardening furnace with continuously operating charging device, a container' for cementing powder having a vertical axis and having the form of a truncated cone, the cross-section of which decreases in upward direction. a device for conveying the cementing powder into vthe furnace, comprising a i Il;

tube of uniform diameter and a screw conveyor which is rigidly connected to the inner surface of said tube, a channel opening into the said container and connectingthe same with the conveyor device, a bottom in the container inclining downwardly towards the entrance to the said channel and means for moving the powder towards the said channel entrance and for forcing it through the said channel. Y

6. In a hardening furnacerwith continuously operating charging device, a container for ccmenting powder having a vertical axis and having the forni of a truncated cone, the cross-section of which decreases in upward direction, a device for conveying the cementing powder into the furnace, comprising a tube of uniform diameter and a'screw con# veyor which is rigidly connected to the inner surface of said tube, a channel opening into the said container and connecting the same with the conveyor device, a bottom in the container inclining downwardly towards the entrance to the said channel, a scraper arranged adjacent `the said channel entrance, the wings of said scraper being bent forward in the direction of rotation of the same at their outer ends and having raised front edges and means for rotating said scraper.

7. In a hardening furnace with continuously operating charging device, a container for cementing powder having a vertical axisk and having the form of a truncated cone, the cross-section of which decreased in upward direction` a device for conveying the cementing powder into the furnace, comprising a tube of uniform diameter and a screw conveyor which is rigidly connected to the inner surface of said tube, a channel opening into the said container and connecting the same with the conveyor device, a bottom in the container inclining downwardly towards the entrance to the said channel, a scraper arranged adjacent the said channel entrance, a member having the form of a double hook. the outer parts of which project in the direction of rotation of the same, said member being arranged adjacent the said scraper and means for rotating the said scraper and the said member.

8. In a hardening furnace with continuously operating charging device, a container for cementing powder having a vertical axis and having the form of a truncated cone,v

the cross-section of which decreases in upward direction, a device for conveying the cementing powder into the furnace, comprising a tube of uniform diameter and a screw conveyor which is rigidly connected to the inner surface of said tube, a channel opening into the said container and connecting the same with the conveyor device, a bottom in Y the container inclining downwardly towards the entrance to the said channel, rotatable members with wings adapted to move the powder towards the said channel entrance and to force it through the same, a widened part on the said rotatable members substantially covering the said lchannel entranceand means'for rotating said members.

9. In a hardening furnace with continuously operating charging device, a container for cementing powder having a vertical axis and having the form of a truncated cone, the cross-section of which decreases in upward direction, a device for conveying the cementing powder into the furnace, comprising a Vchannel entrance and to force it through the same, means for rotating/the said shaft and stirring mea-ns projecting from the said shaft and adapted to stir the contents of the same thoroughly during the rotation of the shaft.

In testimony whereof we aliix our signatures.

ERNST GOERIG. HEINRICH LINDHORST.

vSi)