US 12,220,742 B2
Apparatus method for locating, controlling geometry, and managing stress of hot tops for metal casting
Jonathan Klesch, Spokane, WA (US)
Assigned to Pyrotek, Inc., Spokane, WA (US)
Appl. No. 18/028,172
Filed by PYROTEK, INC., Spokane, WA (US)
PCT Filed Sep. 22, 2021, PCT No. PCT/US2021/051503
§ 371(c)(1), (2) Date Mar. 23, 2023,
PCT Pub. No. WO2022/066733, PCT Pub. Date Mar. 31, 2022.
Claims priority of provisional application 63/082,286, filed on Sep. 23, 2020.
Prior Publication US 2023/0364670 A1, Nov. 16, 2023
Int. Cl. B22D 7/10 (2006.01); B22D 11/04 (2006.01); B22D 11/041 (2006.01); B22D 11/049 (2006.01)
CPC B22D 7/106 (2013.01) [B22D 11/0401 (2013.01); B22D 11/041 (2013.01); B22D 11/049 (2013.01)] 18 Claims
OG exemplary drawing
 
1. A hot top mold assembly system, comprising:
a hot top and a mold, said hot top including a dimension creating a locational clearance fit between the hot top and the mold, the hot top including a collar configured to mate with an end of the mold and a depending edge configured to interface with an internal wall of the mold, wherein the edge includes a deformable feature to improve alignment during assembly of the hot top with the mold and accommodate thermal expansion, wherein the locational clearance fit of the hot top dimension at ambient temperature (SO) is expressed as:

OG Complex Work Unit Math
 wherein MO is a mold dimension at ambient temperature; IO is a mold interface dimension at ambient temperature; α is a coefficient of thermal expansion of bulk hot top material; and ΔT is temperature change between ambient temperature and casting temperature.
 
9. A hot top for use in a hot top mold assembly system, the hot top comprising:
a hot top configured to create a locational clearance fit between the hot top and a mold, the hot top including a annular wall configured to penetrate an opening of the mold assembly, a collar extending radially from an intersection with the annular wall, the collar configured to engage an end surface of the opening of the mold, wherein the annular wall further comprises a feature to restrain or locate a compressible component of the hot top, wherein the locational clearance fit of the hot top dimension at ambient temperature (SO) is expressed as:

OG Complex Work Unit Math
  wherein MO is a mold dimension at ambient temperature; IO is a mold interface dimension at ambient temperature; α is a coefficient of thermal expansion of bulk hot top material; and ΔT is temperature change between ambient temperature and casting temperature.
 
18. A method to reduce thermal stress of a hot top comprising providing a locational clearance fit between the hot top and a mold, wherein the locational clearance fit of the hot top dimension at ambient temperature (So) is expressed as:

OG Complex Work Unit Math
wherein MO is a mold dimension at ambient temperature;
IO is a mold interface dimension at ambient temperature;
α is a coefficient of thermal expansion of bulk hot top material; and
ΔT is temperature change between ambient temperature and casting temperature.