yasui vs old furnaces

If you have ever been in a lost wax casting room that uses gas furnaces, the first thing you experience is the extreme amount of heat being generated by the gas furnaces when they are at full casting temperature. Gold and silver burnouts average 1250 to 1385F. Gas burnout furnaces have been around since the early 1900’s and not much has changed in their designs. They may have one to two gas burners below them, a metal body with fire brick lined walls and they use a 250 pound guillotine style door that goes up and down with the help of a large counter weight.


To address the heat that is emitted from gas furnaces in a casting room, companies have installed massive cooling systems which is very expensive to operate, some build heat “lockers” around the furnaces to try to minimize the heat exposure to the employees, but that requires a lot of valuable space that many companies do not have available. Another down side to gas furnaces are issues such as the amount of dirt that accumulates inside the furnace chamber that will fall into the flasks creating contamination, pilot lights not igniting, liability concerns from a gas furnace , unknown expenses for gas permits and intrusive inspections.

When larger simple electric furnaces were introduced to the jewelry industry as an alternative in the 70-80’s, companies did try them, but many companies ended up staying with the gas furnaces. Gas at the time was still fairly inexpensive. Other noticeable issues with larger electric floor models furnaces produced “dead heat” and “hot spots”. Dead heat exists because there is very little circulation within a closed furnace. Hot spots are found near the side walls; flasks that are closer to the side wall heating elements are hotter then the center of the furnace.

It was not until the last 10-15 years, that more efficient rotating furnaces, that produce uniform controlled heating with upper mounted extraction systems were made available and then the lost wax precision and jewelry casting industry saw the benefits. Todays version of the Yasui RBF’s (Rotating Burnout Furnaces) are at their best level ever and many companies are making the switch. From small to medium size manufacturers to large volume casters.


Comparison cost of traditional Gas Furnaces Vs. Yasui Rotating Electric Furnace:
1. The average cost of 1 Therm https://en.wikipedia.org/wiki/Therm in NYC is $1.26. A Therm is what gas companies base their monthly charges on. 1 CCF (Therm) is equal to 100K BTU  . Most gas burnout furnaces require on average 100 – 150K BTU per hour to run. Therefore, gas burnout furnaces in NYC average about $1.26 -1.89 per hour to run.


2. The aeverage costs for 1 KWH in NYC is only $0.21 per hour.


a. The RBF13 after reaching the 650F, requires 4-5 kwh to maintain and increase to the set casting temperature of 1200 – 1700F. Which equals to $1.05 per hour to run.

b. The RBF37 after reaching the 650F, requires 8 kwh to maintain and increase to the set casting temperature of 1200 – 1350F. Which equals to $1.68 per hour to run.

Conclusion:

There are immediate savings for using a Yasui Electric Furnace over a traditional gas furnace. 

Over the course of a year, the electric furnaces have the capabilities to save you hundreds to thousands of dollars in fuel. Another form of savings is that the electric furnaces do not require the equipment for removing the exhaust and heat from a traditional gas furnace, as well as having more floor space for a more comfortable work environment.

Todays Yasui Rotating Burnout Furnaces are available in two versions, the RBF 13+ and RBF 37+.
The RBF13+ will accept 13ea x 4x11” perforeated flasks or 16ea 3” diameter platinum flasks and will reach a top temperature of 1742F (850C). 
The RBF 37+ will accept 37 4x11” perforeated flasks and will reach a top temperature of 1562F (950C).

yasui comparison chart

The new Yasui programmable controller allows the operator to customize endless programs based on his applications. Programs for traditional injection wax, complicated multi-ramp and holds are required for resin burnouts, stone in place burnouts that require precise temperature control to protect the stones and many other applications.

The initial dewaxing procedure will capture the injection wax prior to the furnace ramping up, resulting in a cleaner burnout. 

The top mounted after burner system reaches 2000F+ which vaporizes any smoke or residue, therefore smoke and smells are eliminated.

Yasui's are equipped with memory flask locations, so as you load each flash and assign a number, you can have the furnace bring your selected flask to the front of the door prior to opening. This reduces the time needed for each flask. 

The door opening for the flask chamber is narrow which reduces the amount of heat exposure to the room. The YASUI RBF exterior body is cool to the touch and emit no heat while the door is closed.

The RBF 37+ features a foot pedal for easily opening and closing the door.

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