Rather than a blind riser
, which does not reach the exterior of the mold, Reamer suggests using a runner from the gating system to feed the riser.
Depending on its position in relation to the top or edge of the mold, the blind riser is subject to uneven and limited exposure to atmospheric pressure.
Before the sand is packed in the mold, the chamber is placed on top of the blind riser sleeve.
On the carousel, the wheels are single-poured into one of two side gates, while the other gate is blocked with a mold insert to become a blind riser
. A different insert is used and the second side gate is opened, at which point static hand-pourwheels are poured "two-up." All GPM wheels are cast with a riser on the center hub and the upper rim (a ring-riser).
The filter is located vertically in the runner area near the blind riser, and the two ingates are opened on the sides of the blind riser.
For #10075, which originally had an oxide problem in the section near the ingate, there are two blind risers in the mold and two separated runners are used to connect the sprue with the blind risers.
If a blind riser is to feed a steel casting properly, it is important that the riser neck stay open until the casting solidifies.
If it is not possible to route hot metal into the blind riser, there are other solutions such as opening the riser through the cope or enlarging its diameter.
Blind risers have been in widespread use in the steel foundry industry since the 1940 patent by John Williams that used a sand core to provide a hole in the metal skin of a blind riser.
This puncture hole allows the atmospheric pressure to push on the liquid metal in the blind riser so that it may feed the casting.
Company Q: Uses only exothermic sleeves for its blind risers
. For open risers, it uses insulating sleeves for risers less than 6 in.
* eliminating blind risers
located below an open riser with a heavy section connecting them;