US722312A

US722312A - Apparatus for drying molds and cores.

Info

Publication number: US722312A
Application number: US10794902A
Authority: US
Inventors: William L Mars
Original assignee: Individual
Current assignee: Individual
Priority date: 1902-05-19
Filing date: 1902-05-19
Publication date: 1903-03-10
Anticipated expiration: 1920-03-10

Description

No. 722,312. PATENTED MAR. l0, 1903.

` W. L. MARS.

APPARATUS FOR DRYING MOLDS AND CORES. v

n APPLIOATION FILED MAY 19. 1902. xoMoDEi.. v s SHEETS-SHEET 1.

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PATENTBD MAR. 10, 1903`.

l W. L. MARS. APPARATUS FOR DRYING MOLDS AND CORI-IS.

APPLIUATION `FILED MAY 19, 1902.

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APPARATUS FOR DRYING MOLDS AND GORES.

APPLIOATION FILEDl MAYV 191Y 1902.

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WILLIAM L. MARS, OF BUFFALO, NEW YORK.

APPARATUS FOR DRYING MOLDS AND CORES.

SPECIFICATION forming part of Letters Patent No. 722,312, dated March 10, 1903.

Application iiled May 19, 1902. Serial No. 107,949. (No model.)

To @ZZ 1072/077?, it may concern:

Beit known that I, WILLIAM L. MARS, a citizen of the United States, residing at Buffalo, in the county of Erie and State of New York, have invented new and useful Improvements in Apparatus forDrying Molds and Cores, of which the following is a specification. Y

This invention relates to an apparatus designed more particularly for drying the molds and cores employed in casting pipes, such as water and gas pipes. As is well known in this art, such molds and cores are composed principally of sand or earth and coated with pulverized coal or blackiug to protect the sand and cause the molten metal to flow freely in casting. Before being dried the molds and cores contain considerable moisture, and unless the evaporated moisture or steam produced in drying them is carried off as rapidly as the same is formed it condenses or causes sweating of the molds and cores. i/Vhen this occurs, the water washes oif the blacking or coating of the mold, particularly at its lower end, where the usual enlargement or bell of the mold forms a channel in which the Water collects before the mold is fully dried. Upon pouring molten metal into such a mold the metal cuts the exposed portion of the sand lining and some of the sand becomes incorporated with the metal, thereby scabbing the casting and rendering the same unt for high-pressure service.

The object of my invention is to provide an efficient drying apparatus which will quickly and completely carry off the moisture of the molds and cores, so that sweating and scabbing cannot take place and all liability of producing inferior castings is avoided.

In the accompanying drawings, consisting of three sheets, Figure l is a front elevation of the furnace. Fig. 2 is a vertical longitudinal section of the drying apparatus, the plane of the section being in line 2 2, Fig. 4. Fig. 3 is a detached sectional elevation of the retarding devices, which control the action of the dampers. Fig. 4 is a horizontal section in line d 4, Fig. 3. Fig. 5 is a horizontal section of the apparatus in line 5 5, Fig. 2. Fig. 6 is a fragmentary vertical section in line 6 6, Fig. l, on an enlarged scale. Fig. 7 is a transverse vertical section of a modified construction of the apparatus designed more especially for drying cores.

Like letters of reference refer to like parts in the several figures.

Referring to the construction', shown in Figs. l to 6, A indicates a furnace of anysuitable or approved construction located above the surface of the ground and having its fire or combustion chamber A provided with the usual door A2 and its ash-pit A3 with a draftdamper A4. The combustion-chamber is provided in its side walls above the grate` with air-inlet apertures b,which communicate with longitudinal flues B, arranged on opposite sides ofthe furnace and extending throughout its length, as shown in Fig. 5. These Iiues are provided in their front walls with air-inlet openings, which are controlled by checkdampers B'.

C indicates an oven or drying-chamber which communicates with the combustionchamber of the furnace and in which the molds D to be dried are placed in an upright position, as shown in Fig. 2. The molds are introduced at the top of the oven, which is normally closed by a removable cover E. The top of the oven is preferably about on a level with the top of the furnace, and the oven is slinken a sufcient distance below the surface of the ground to bring the top of the molds a short distance above the bridge-wall of the furnace. The oven may be extended laterally on opposite sides of the furnace to increase its capacity, that shown in the drawings being large enough to receive twelve molds at a time.

F indicates Ventilating-pipes, which rise through the bottom of the oven O and with which the central apertures d of the seats d' and sockets d2 of the molds are adapted to register, as shown in Fig. 2. ing-pipe is provided for each mold, and the several pipes are connected by branch pipes f With a main Ventilating pipe or liue F, which latter is connected with or terminates in a chimney F2. draft through the several Ventilating-pipes F, the main Ventilating-line F is tapered toward the end farthest from the chimney, as shown by dotted. lines in Fig. 5. The area of the largest or discharge portion of this main flue is equal to the aggregate area of the sev- Such a ventilaty In order to equalize the 1 IOO eral branch pipes connected therewith. The

oven is provided with a number of additional ventilating-pipesf2, which open into the same between the molds for carrying olf the moisture in the oven outside of the molds. In the drawings three of such auxiliary ventilating-pipes are shown, which are connected directly to the main flue F. The top or cover E of the oven is tight or imperforate to eX- clude the outer atmosphere at this point and avoid weakening of the draft through the oven, and the combustion-chamber of the furnace opens into the upper portion of the oven adjacent to the cover, so that the hot air and products of combustion upon issuing into the oven immediately enter the adjacent upper ends of the molds. By this construction and arrangement of the drying apparatus a downward draft of the products of coinbustion and hot air from the furnace is created from the top of the oven through the tubular molds resting on its bottom, as indicated bythe arrows in Fig. 2, the hot air and products of combustion passing thence through the various Ventilating and branch pipes Fff into the main flue F and escaping finally through the chimney. The molds are by this means quickly dried, and the steam or evaporated moisture is withdrawn from the oven before condensation can take place. All liability of washing the molds and proy ducing defective castings is therefore avoided.

Heretofore the furnace has been located in a pit and the oven has been arranged above the furnace, the products of combustion ascending through perforations in an iron plate which forms the top of the furnace and the bottom of the oven. This plate soon burns out and requires frequent renewal. The arrangement of the furnace below the surface of the ground is also objectionable, because it requires the fuel to be lowered and the ashes to be elevated. By arranging the furnace on the surface of the ground and extending the oven below the surface the plates above referred to are dispensed with and the laborious handling of the fuel and ashes incident to such a sunken furnace is obviated. Owing to the rapid withdrawal of the moisture effected by this apparatus, the same is especially desirable for drying molds in which the bell or enlargement is at the bottom; but the apparatus is equally useful for drying molds in which the bell is at the top.

In order to insure an ample air-supply and a thorough and uniform ventilation of the oven, the furnace is preferably provided with an automatic regulating device, which operates to open the draft-damper A4 and close the check-dampers B when fresh coal is supplied to the furnace and gradually closes the draft-damper and opens the check-damper when the iire gets under way. This regulating device is constructed as follows: H indicates a double-acting dash-pot or cylinder secured vertically to the front wall of the furnace adjacent to the hinged side of the fueldoor A2 and containing a tightly-fitted piston h. This piston has rods h' h2, which extend through stuffing-boxes at opposite ends of the cylinder. The latter is provided at opposite sides with longitudinal passages or by-passes t' fi', which open at their upper ends into the top of the cylinder and at their lower ends into valve-chambers i2 i3, which communicate with the bottom of the cylinder by ports 1141'5, respectively. One of these by-passes, which will hereinafter be termed the free bypass, is comparatively large to permit a practically-unrestricted flow of the oil or other liquid through the same in one direction. The valve-chamber of this by-pass contains an automatic check-valve i, which closes upwardly against a valve-seat at the lower end of the corresponding by-pass for checking the upward ow of the liquid from the portion of the cylinder below the piston into said bypass when the piston descends, but permitting the free downward flow of the liquid through said by-pass into the bottom of the cylinder when the piston ascends. The upward ow of the liquid from the bottom of the cylinder through the other by-pass t', hereinafter termed the restricted by-pass, is controlled by a hand or regulating valve 117, applied to the lower end of said pass and extending through a stuffing-box]l at the lower end of the cylinder. This regulating-valve is adjustable toward and from its seat, and for this purpose its stem is preferably screwthreaded and engaged with a screw-thread in the bore of the stufing-boxj, as shown in Fig. 3. By adjusting this valve more or less closely to its seat the upward passage of the liquid through the restricted by-pass is retarded accordingly and the descent of the piston is retarded in the same measure.

K indicates a vertically-swinging quadrant or lever fulcrumed on a horizontal stud 7c, projecting from the front wall of the furnace and having its upper arm pivotally connected with the lower piston-rod h2. The same arm of the lever is provided with a weight c, which tends constantly to lower the piston in the cylinder H.

L indicates a vertically-swinging shifting arm mounted on the stud 7o and adapted to strike against lugs or shoulders Z, arranged on the lower arm or portion of the quadrantshaped lever K. The free lower end of this shifting arm is connected with a lugm of the fuel-door by a link m. This lug projects forwardly beyond the pintles of the doorhinges, as shown in Fig. 5, so that upon opening the door the shifting arm is swung laterally away from the door and caused to strike the shoulder Z of the lever K, thereby reversing the latter from the position shown in Fig. 1 to that shown in Fig. 3 and raising the piston in the cylinder I-I. Upon closing the fueldoor the shifting arm L is withdrawn from the shoulder of said lever, allowing the lever to return to its former position under the action of its weight. In order to prevent bind- IOO IIO

ing of the connections between the fuel-door and the piston, the cylinder is mounted to oscillate on trunnions h3, carried by a yoke Il. This yoke is secured to the front of the furnace.

N indicates a transverse rock-shaft supported ou the front wall of the furnace above the horizontal pintles of the draft-damper A4. This shaft has an actuating-arm n for rocking it and a second arm n, with which the draft-damper is connected by a link n2. A second transverse rock-shaft 0 is arranged on the front wall of the furnace above the checkdampers B for operating the latter. This shaft has an actuating-arm o and arms 02, with which the verticallyswinging checkdampers are connected by links 03. Both of the rock-shafts N and 0 are operated by a cord or chain p, secured to the weighted lever K, as shown at p. The ends of this cord are secured to the actuating-arms n and 0 of the two rock-shafts, and the upper portion of the cord is doubled around a guide-pulley q for rocking the shafts in opposite directions and causing the check-dampers to be closed when the'draft-damper A1 is opened, and vice versa.

It will now be understood that upon opening the fuel-door to feed the furnace the shifting lever L takes part in the movement of the door and strikes the shoulder Z of the quadrant-lever K, thereby reversing the latter and elevating the piston 71.. By this movement the cord p is pulled and caused to turn the lower rock-shaft N in the proper direction to open the draft-damperA, and at the same time the upper portion of the cord is slackcned, allowing the check-dampers B to close by gravity. After feeding the furnace the fueldoor is closed, this movement of the door returning the shifting lever L to its former position without affecting the position of the quadrant-lever K and the parts connected therewith. By the upward movement of the piston hthe liquid above the same Was transferred to the portion of the cylinder below the piston, the same being forced downward through the free by-pass t' and past the checkvalve is. In the absence of the retarding device the elevated weight of the quadrant-lever K by its tendency to descend would immediately lower the piston and reverse the position of the draft and check dampers; but inasmuch as the return of the liquid to the upper side of the piston is retarded by the constriction in the by-pass t" the piston is allowed to descend, but very slowly, under the action of the weight, and hence after the fuel-door has been closed the draft-damper is slowly and gradually closed and the checkdampers are as gradually opened. The descent of the piston is so timed by means of the regulating-valve l that the check-dampers are not fully opened nor the draft-dam per fully closed until the fresh charge of fuel burns brightly. By this improved regulating device an abundant volume of air is supplied to the drying-oven under all conditions and a thorough ventilation of the oven is insured at all times. In order to supply a uniform quantity of air regardless of whether the draft-damper or the check-dampers are open, the area of the draft-damper is about equal to the aggregate area of the checkdampers.

When my improved apparatus is employed for drying cores, the same is preferably modiiied, as shown in Fig. 7. In this case the oven, as well as the furnace, is located above the surface of the ground, and when two ovens are employed, as shown, the furnace is arranged between the same. The ovens communicate with the combustion-chamber .by passages rr. The cores S are supported horizontally on trucks or carriages running upon tracks laid on the bottom of the ovens. F3 F4 indicate the main Ventilating-line and the Ventilating-pipes connected therewith and opening into the bottom of the ovens, preferably between the tracks. In this form of the apparatus a downdraft is created through the ovens, as in the apparatus first described.

I claim as myinventionw l. In an apparatus for drying molds and cores, the combination of an oven having a closed or imperforate top, a furnace having its combustion-chamber in direct communication with the upper portion of the oven and provided on opposite sides of said chamber with longitudinal air-inlet fines which communicate with the chamber', a main ventilating-pipe, and branch pipes connected with said main pipe and extending through the bottom of the oven, substantially as set forth.

2. In an apparatus for drying molds and cores, the combination of an oven having a closed or imperforate top, a furnace having its combustion-chamber in direct communication with the upper portion of the oven, a main Ventilating-pipe arranged underneath the oven, connected at one end with a stack or chimney and constructed of gradually-decreasing diameter from thestack toward its opposite end, and branch pipes connected with different portions of said main ventilating-pipe and opening through the bottom of the oven, substantially as set forth.

fitness my hand this 15th day of May, 1902.

WILLIAM L. MARS.

Witnesses:

THEO. L. Polar, CARL F. GEYER.

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