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Dip-type heater holding furnace

Heater tubes in a furnace Heater tubes in a furnace
Convection of molten metal Convection of molten metal

A technology to make Dip-type heater holding furnace (Horizontal soaking type heater holding furnace) was developed by Tounetsu’s founder, Shunji Mochizuki in 1982.
In the past holding furnaces had many problems such as bad thermal efficiency and a lot of oxide. To resolve such problems, Dip-type heater holding furnace was developed after getting over many difficulties such as molten metal leak in trial production.
This furnace was developed for low pressure die casting at first, but it came to be used for die casting gradually. Dip-type heater holding furnace for die casting is named "Al-Under" (a registered trademark in Japan), and until now, it has been well received by customers in casting industry.
The number of our furnaces using this technology for die casting and low pressure casting is over 3000 all over the world.

What is Dip-type heater holding furnace?

Dip-type heater holding furnace is a furnace whose heater is inserted from furnace’s side wall.
This furnace's whole heater is placed under molten aluminum, so thermal efficiency is better than a vertical dip type heater or a radiation type heater, and it has a big effect on energy saving and a reduction in oxide at the surface of molten metal.

Merits of Dip-type heater

1. Reducing oxide
Reducing overheating, oxide and a loss of aluminum
Decreasing a frequency of cleaning
2. Good thermal efficiency
Less heat loss and short heat-up time contribute to energy saving.
3. Temperature homogenization of molten metal
Because of convection of molten metal in furnace by heating from the bottom, it homogenizes temperature of molten metal and contributes to improvement of quality of molten metal.

Related Tounetsu’s Products

・Holding furnaces for die casting (Al-Under)
・Holding furnaces for low pressure die casting

Supplying system of molten metal

ALPS図解

Tounetsu is developing a new supplying system of molten metal for further development of aluminum casting.
Molten metal is usually transferred from melting furnace to holding furnace by a ladle -- melted aluminum is transferred from melting furnace into a ladle, and a worker carries it by a forklift and pours molten metal into holding furnace.
Molten aluminum forms an oxide film on the surface by exposed to air. In the case of using ladle, an oxide increases and becomes thicker by strong waving of the surface and temperature change.
An increase of oxide causes an increase of aluminum loss, molten aluminum pollution and debasement of casting products. We developed "ALPS" so as to decrease exposure to air while supplying molten aluminum, which is more effective than conventional way.

What is ALPS?

ALPS is a supplying system of molten aluminum by connecting furnaces with heated pipes. Compared with usual method by ladles, it can decrease aluminum loss, maintenance cost and management cost.
ALPS's main features are as below:

1. Works by siphon effect
Filling pipes with molten aluminum and decreasing pressure in ALPS, and molten metal flows automatically into furnace whose molten metal is small in quantity from furnaces on both sides. (Actually level of all furnaces' surfaces are always the same height.)
2. Set on furnaces without fixing
Since pipes are not fixed just placed on furnaces, so ALPS can be introduced without changing places of existing furnaces.

Merits of ALPS

1. Greatly reduces aluminum loss
Inside of pipes, only depressed parts are exposed to air. Besides, when transferring molten metal, involvement of air and waving of metal surface hardly occur compared with conventional way (by a ladle). Hence, it can reduce aluminum loss caused by occurrence of oxide to about one-sixth.
2. Improves working environment
Since transfering by ladle and forklift are not necessary, the problems such as splashing of molten aluminum, air pollution by exhausted gas and physical injury in factory are solved.
3. Reduces maintenance cost and management cost
Maintenance and management cost including employment cost or parts cost are reduced to about one-third.
4. Safety measures in case of earthquake
In case of emergency such as earthquake, the atmosphere of decompressed points in ALPS is returned to atmospheric pressure automatically, and molten metal in pipes flows down into furnaces, so molten metal dosen't leak from pipes.

Specifications of ALPS

Please see "ALPS" (piping system for supplying molten metal) of products page.

Main Development Projects

June, 1982 Dip-type heater holding furnace
May, 1987 Extreme heat furnace
December, 1988 Piping device for supplying molten metal
December, 1992 Stalk-less type 3 chambers holding furnace for low pressure die casting, named "NewLP"
Patent No. 4615300, 4519806
March, 1993 Device for removing slag
August, 1993 Metal mold preheating burner
Patent No. 4290536
July, 1996 Floating type level sensor
November, 1996 Apparatus for supplying molten metal at predetermined rate, named "Al-Heart"
Patent No. 3628040, 3675810, 3017540, 4095157, 3492194, 3553408, 3756040
Received a distinguished service prize for devices in 30th Invention Award hosted by The Japan Society for
The Advancement of Inventions and Nikkan Kogyo Shimbun Ltd. in 2005
February, 1999 Holding furnace for supplying molten metal at predetermined rate, named "Al-Heart type holding furnace"
Patent No. 3485826, 4431078
August, 2005 Dip-type spiral heater
WO2009/096311
July, 2006 Pre-casting method
November, 2006 Board bath method
December, 2008 Removing wax and sintering vacuum furnace with direct-exhaust system, named "CAVAC"
Patent No. 5265475
December, 2008 Apparatus for purifying molten aluminum
June, 2009 Piping system for supplying molten metal, named "ALPS"
Patent No. 5237752
September, 2009 Hammer crusher for heat insulation board
December, 2009 Vertical dip-type electric heater for molten metal, named "Atom heater"
June, 2012 Dip-type heater in heat insulation board

Patents

Granted patents in Japan

  • ■ Valve for molten metal of furnace maintaining molten metal level (Patent No. 3392544)
  • ■ Furnace maintaining molten metal level (Patent No. 3415686)
  • ■ Rotary retort type heat treatment furnace (Patent No. 4782326)
  • ■ In-line type degasser (Patent No. 4248798)
  • ■ Holding furnace for high pressure die casting (Patent No. 4139127)
  • ■ Filter device for molten metal (Patent No. 4268679)
  • ■ Detection sensor for molten metal level (Patent No. 4386822)
  • ■ Holding furnace for low pressure die casting and supplying method of molten metal for it (Patent No. 4422045)
  • ■ Stalk-less type 3 chambers holding furnace for low pressure die casting, named "NewLP" (Patent No. 4615300, 4519806)
  • ■ Metal mold preheating burner (Patent No. 4290536)
  • ■ Apparatus for supplying molten metal at predetermined rate, named "Al-Heart" (Patent No. 3628040, 3675810, 3017540, 4095157, 3492194, 3553408, 3756040)
  • ■ Holding furnace for supplying molten metal at predetermined rate, named "Al-Heart type holding furnace" (Patent No. 3485826, 4431078)
  • ■ Piping system for supplying molten metal, named "ALPS" (Patent No. 5237752)
  • ■ Removing wax and sintering vacuum furnace with direct-exhaust system, named "CAVAC" (Patent No. 5265475)
  • ■ Dip-type spiral heater (Patent No. 5371784)

Pending patents in Japan

  • ■ 1 chamber holding furnace for low pressure die casting (Published patent application: 2013-46922)

Granted patents overseas

  • ■ Apparatus for supplying molten metal at predetermined rate, named "Al-Heart" (EP0901854)
  • ■ In-line type degasser (US6887424, EP1336664)
  • ■ Holding furnace for supplying molten metal at predetermined rate, named "Al-Heart type holding furnace" (EP1820585, US7790098, ZL200580040536.5, KR101132930)
  • ■ Stalk-less type 3 chambers holding furnace for low pressure die casting, named "NewLP" (ZL200580040536.5, KR101132930)
  • ■ Dip-type spiral heater (US8422871)
  • ■ Dip-type spiral heater (ZL200980103393.6)

Pending patents overseas

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