US1255103A - Lead-supply system for pig-casting machines. - Google Patents

Description

J. F. MILLER.

LEAD SUPPLY SYSTEM FOR PIG CASTING MACHINES.

APPLICATION FlLED SEPT-26,1916.

Patented Jan. 29, 1918 llll 5] nuewfoz 351g 61am 6, 62%. a

JOHN F. MILLER, OF TRAIL, BRITISH COLUMBIA, CANADA.

LEAD-SUPPLY SYSTEM FOR PIG-CASTING MACHINE S.

Specification of Letters Patent.

Patented Jan. 29, 1918.

Application filed September 26, 1916. Serial No. 122,187.

To all whom it may concern Be it known'that I, JOHN F. MILLER, a citizen of the United States, residing at Trail, British Columbia, Dominion of Canada, have invented certain new and useful Improvements in Lead-Supply Systemsfor Pig-Casting Machines, of which the following-is a full, clear, and exact description.

In the use of machines for casting lead pigs it is desirable that the temperature of the molten lead be kept as little above the melting point as possible, not only to economize the fuel used in melting the bullion but also to keep down the heat absorption necessary to solidify the lead in the molds. Moreover, lead does not expand, as does iron, but contracts in passing from the molten to the solid state, and hence the nearer the molten metal is to the melting point the less does it contract in the mold. On the other hand if the temperature is :too low, the metal is very apt to freeze at the outlet of the pipe .by which it is delivered to the molds, thereby necessitating thawing the pipe out before the casting can proceed. This is a not uncommon occurrence unless great care is exercisecl, especially when the operation is be- I gun and the machine is cold.

' the metal cools (and contracts) the space I have accordingly been led to devise my present invention, which has .for its chief object to provide a lead-supply system by which freezing is minimized and any lead that solidifies at the outlet of the supply pipe will be quickly melted. Another object is to provide a supply system in which a static head will be maintained against the molten metal in each mold as it is. filled, so that as thus formed will be filled with additional metal thereby insuring pigs of uniform size. To these and other ends the invention consists in the novel features and combinations hereinafter described.

One form of the invention is illustrated in the accompanying drawings, in which the same is shown in side elevation, partly in section.

In the apparatus illustrated, 10 is a portion of the rim of the revolving vertical mold-wheel, having outwardly open pigmolds 11 on its periphery and an inner water-jacket or backing12. On the outside is a stationary arc-shaped water-'aclzet 13, of suitable circumferential extent gsay about 100) to close the molds as they pass. .In'

its lower portion the outer jacket is formed with a depression 14, and through this depression the lead supply pipe 15 extends into communication with the molds. The purpose of this depression is to diminish the cooling eflect of the jacket on the supply 'pipe. No claim is made herein to this feature per 86, as it-is claimed broadly-in'my psior Patent No. 1,157,794, dated October 26,

15. The supply pipe 15, which is connected with a suitable. pump (not shown) for delivering molten lead, includes a T 16, in the outer end of which is screwed a bushing 17 having a threaded central aperture to receive a short length of externally threaded pipe 18. The latter extends toward the inner end of the T and at its inner end carries a short intake pipe 19. This pipe terminates close to the orifice of the lead-supply pipe 75. 15 and its inlet orifice is beveled at an angle of about 45 on. the underside, as shown. The outer end of the connecting pipe 18 is screwed into a bushing 20 (like bushing 17 in the lower end of a lead-return pipe 21 which leads back to the source of molten lead, notshown. This return pipe is arched a slight distance above the top of the supply pipe 15, as shown.

' will be speedily melted again by the stream of hot metal flowing around and into the pipe 19, thus making it unnecessary to dismantle system or have recourse to a torch or otherlexternal source of-heat; unless of course, the metal should congeal back to the vertical portion of the supply pipe and choke the same. -In such case (which will not occur if ordinary care andintelligence are used the outlet can be thawed outby means 0 a blow-torch flame applied to the outside of the pipe. The beveling of the end of tube 19 is of advantage in that it enlarges the area of the orifice, making-it less liable to freeze over, and carries the orifice back farther while keeping the end of the pipe near the orifice of the supply pipe. 4

As the casting continues the excess-metal delivered by the supply pipe accumulates in the short leg of the return pipe and soon overflows through the bend and into the depending leg. There now exists on the metal flowing into the molds a constant head equal to the height of the return bend above the outlet of the supply pipe. Hence, as the metal in the mold cools and contracts (contraction begins as soon as the molten metal strikes the relatively cool walls of the mold) additional metal is forced in at a pressure that is constant by reason of the constant height of metal in the return bend. This pressure is exerted on each individual mold from the time when it first reaches the supply pipe until it leaves it, and the mold is therefore full at the instant it is entirely past the pipe. By this time the metal, while perhaps not solidified, is cooled down near to the point of solidification. By that time most of the contraction has occurred, leaving very little to take place afterward. The result is that the contraction after the mold is filled is scarcely appreciable, thus giving pigs that are smooth and clean on all surfaces.

lit isto be understood that the invention is not limited to the construction herein specifically illustrated and described but can be embodled in other forms without departure from its spirit.

I claim: 1. In a machine for casting lead pigs, the combination with a mold wheel provided with open molds on its periphery, of an outer arc-shaped member fitting the periphery to close the molds as they pass, a supply pipe extending through said member to deliver molten lead to the molds, and a rethey pass, a supply pipe extending throughsaid member to deliver molten lead to the molds, an intake tube of relatively small diameter inside the supply pipe, arranged with itspinlet orifice adjacent to the outlet orifice of the supply pipe, to receive excess metal, and areturn plpe connected to the other end of the intake tube for carrying ofi' the excess metal.

3. In a machine for casting lead pigs, the combination with a revolving mold wheel having a plurality of open molds on its periphery, of an arc-shaped member fitting said periphery to close the molds as they pass, a supply pipe extending through said member to deliver molten lead to the molds, a return pipe arched above the supply pipe, and an intake tube of relatively small diameter extending from the return pipe into the supply pipe and terminating adjacent to the outlet orifice of the latter.

Tn testimony whereof ll hereunto affix my signature.

JOHN F. MILLER.

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