Abstract The invention relates to a method for continuous vacuum casting of metals or other materials and a plant for effecting said method more particularly for the obtention of shapes and tubes. The method applicable to plants comprising a spray means in the open air and a dynamic lock for emergence into air,comprised of chambers which are maintained under decreasing pressures by pumping devices of known types and are separated from each other by diaphragms, consists, on the one hand, in holding the static pressure of the metal on the shape or tube being formed at a constant value, for a given size with respect to the liquid meniscus size, so as to render the permissible difference between the cross-section of said shape or tube, when reaching the dynamic lock, and the cross-section of said diaphragms low enough for the rate of air admission to remain in all cases lower than the pumping rates of said pumping devices, and, on the other hand, in so selecting the cooling zone length, as a function of the suitably set rate of withdrawal of the moulded shape, that said shape will enter the spray means, when leaving the lock, at a constant, controlled temperature. The invention is especially applicable to the obtention of uranium shapes or tubes.
A plant for continuously casting metal or metal alloy material comprising the combination of a vacuum chamber; a ladle located within said vacuum chamber; a flow-rate control system associated with the ladle; a distributor provided with a nozzle receiving the liquid material released by the flow-rate control system; a vertically extending ingot mould having a liquid material receiving end and an ingot egress end and a water circulating system; a first servo-mechanism for adjusting the flow-rate control system; a level detector for controlling said first servo-mechanism; a vacuum cooling jacket adjacent said ingot mould ingot egress end; a dynamic lock comprising a plurality of suction chambers aligned in the direction of ingot travel therethrough and being connected respectively to vacuum pumps of successively increasing ratings, and dynamic seals separating said chambers; a pneumatic seal adjacent that suction chamber which is downstream in the direction of ingot travel through said dynamic lock, said pneumatic seal delivering a neutral gas blast acting simultaneously to seal and as a cooling medium; cooling spray means arranged outside the vacuum chamber at the outlet of said dynamic lock; variable speed ingot withdrawal and guiding means; a second servo-mechanism for varying the speed of said ingot withdrawal and guiding means; a temperature detector at the outlet of the vacuum cooling jacket for controlling the operation of said second servo-mechanism; the power operated means for reciprocating said ingot mould vertically.
Claim 2
Dependent Claim
17 words
A plant according to claim 2 in which said power operated means comprises a cam and follower.
Claim 3
Dependent Claim
33 words
A plant according to claim 3 in which said cam is contoured to impart a relatively slow downward movement to said ingot mould and a relatively rapid upward movement to said ingot mould.
Claim 4
Dependent Claim
23 words
A plant according to claim 2 in which said level detector is stationary with respect to said ingot mould and is under vacuum.
Claim 5
Dependent Claim
52 words
A plant according to claim 2 including, for the production of cored tubes, a second dynamic lock for introducing the core into said vacuum chamber; guiding means for aligning said core with the axis of the ingot mould; and a core heating device for heating said core upstream of said ingot mould.
Claim 6
Dependent Claim
41 words
A plant according to claim 6 in which said core heating device is under vacuum and said second dynamic lock includes, from outside to inside said chamber, a sliding seal surrounding said core; a suction chamber; and a threaded dynamic seal.