GB724991A - Feed-trough for centrifugal casting machine - Google Patents

Abstract

724,991. Centrifugal casting-machines. COMPAGNIE DE PONT--A-MOUSSON. Jan. 1, 1953 [Jan. 10, 1952], No. 32/53. Class 83 (1). A single-piece pouring- trough for a centrifugal pipecasting machine, having all the transverse cross-sections of its wall inscribed in circles of the same radius, is characterized in that the cross-sectional area of the channel increases, at least on the part of the trough adjacent the pouring end thereof, said area being such that each of said transverse cross-sections of the wall has its centre of gravity substantially coincident with the centre of gravity of the part of the corresponding cross-section of the channel situated below a transverse horizontal line which is at a constant distance below the upper edges of the channel. For any given rate of pouring from the ladle into the trough, an inclination of the trough may then be found which is such that the level of the molten metal flowing freely in the channel coincides in each cross-section with the aforementioned transverse line and it is stated that the trough then undergoes substantially no distortion due to thermal expansion. The various cross-sections of the trough are inscribed substantially within a circle C and the centre of gravity G<SP>1</SP>-G<SP>3</SP> of the total section of the wall coincides with the centre of gravity of the shape a<SP>1</SP>, b<SP>1</SP>, c<SP>1</SP>-a<SP>3</SP>, b<SP>3</SP>, c<SP>3</SP> of the portion of the channel 11 situated below a transverse horizontal line a<SP>1</SP>, c<SP>1</SP>-a<SP>3</SP>, c<SP>3</SP> which is situated at a constant distance l from the upper edge of the channel. The distance l is preferably of the order of one third of the total depth of the channel for casting pipes of less than 100 mm. diameter and one half of the channel height for pipes of greater diameter. The width of the channel remains substantially constant from the upstream end, Fig. 4, for about two thirds of its length to the section shown in Fig. 5, and then increases by about 10-15 per cent along the remainder of its length to the downstream end, Fig. 6. The thickness of the bottom decreases progressively from 2e at the upstream end to substantially e at the downstream end. The increase in the channel section is stated to ensure that, as the molten metal gets less fluid due to its cooling as it travels along the trough, the level of the free flow does not rise but remains at a constant distance from the upper edge of the channel.