Electric Aluminum Holding Furnace for for Aluminum Die Casting

1. General Introduction
The pool type aluminum holding furnace is mainly used for preserving
the temperature of the non-ferrous metal. It is mainly used in die casting,
centrifugal casting and gravity casting area.
The aluminum die casting furnace is comprised of furnace body, heating
components and electrical control system. The upper part of the control
box is for control loop while the lower part for power loop. The furnace body
is mainly comprised of charging port, holding chamber and discharging port.
The furnace body is made from sectional steel and steel plate. The holding
chamber is made of non-sticky aluminum casting material. On the roof there
are the heating components and heat preservation material which can radiate
over the molten aluminum surface. This electrical heating system has a
high heat efficiency, and is easy for maintenance.

2. Lining
The casting material is once-forming casting cement (supplied by Allied
Mineral Products, Inc.), which has the advantages of high strength, not
sticking with molten aluminum, easiness to be cleaned, and long service
life (compression strength: 140Mpa at a temperature higher than 110℃;
linear change rate: 0.1%). The aluminum holding furnace cover is lined
with Japanese Iso refractory fibers which have the advantage of good heat
preservation performance and a long service life.

3. Electrical Control System
3.1 main components
a) heating component: silicon carbon rod (6 pieces per set);
b) control system: temperature controller (Taiwan brand, 2 pieces),
electronic power regulator, contactor, relay.
temperature sensing component: thermal coupling (2 pieces in together,
1 for measuring the hearth atmosphere temperature and another for
measuring the molten aluminum temperature)

3.2 Electrical control system (PID control)
The thyristors are the main controlling component of the electrical control
system. The output current is controlled through the change of the
conduction angle of the thyristor. The furnace employs the advanced
phase control and firing circuit to control the conduction angle of the
thyristor. The temperature controller has various protection functions such
as soft start-up, over-current protection and over-temperature protection.
When the furnace temperature rises over the upper limit or the current
is abnormal due to faults, the controller can automatically stop pulse
output, and stop power supply.
3.3 Temperature control accuracy
±5℃( under standard working conditions)

4. Technical Parameters