Volume 2, Number 2

 

 

When PCC Airfoils in Douglas, GA, set out to purchase a new pusher furnace, environmental emissions were a prime motivating factor. A corporate philosophy to be environmentally proactive and to implement state of the art technology was evident in the furnace specification, which dictated stringent air emissions. The challenge was further increased by the wax and plastic load, which exceeded 20 lbs. per cycle.

 

When they approached Pacific Kiln with the problem, it was clear that a furnace with an "off-the-shelf" afterburner was not going to meet their needs. Pacific Kiln conducted an engineering study, which included an evaluation of their current flash fire practice. Firing one shell at a time, the existing batch furnace produced a large quantity of VOC and particulate emissions. Although they were within the State emission limits, the visible emissions were an eyesore, and the throughput was severely limited.

 

Pacific Kiln designed a continuous pusher furnace with a custom afterburner to handle the very high emissions loading produced by the process. The afterburner was warranted to reduce particulate and VOC emissions by 99 percent. The design incorporates many new custom features that Pacific Kiln has developed through extensive testing on numerous afterburner projects. Recent air emissions testing at PCC indicated no visible emissions (smoke) and a destruction efficiency greater than 99.9%.

This is only part of the good news for PCC. The pusher furnace provides state-of-art temperature control and a user-friendly design. The furnace has dramatically increased throughput and reduced shell cracking. The furnace was installed in less than a week from the time they received it, and Pacific Kiln was there to assist with start-up and commissioning.

 

 

FOUNDRY FACTS

Dear Pyro

 

   "Our foundry has grown rapidly and we're considering changing from batch furnaces to continuous furnaces. What drives this decision in most foundries?" - Undecided

 

Dear Undecided

This is a big step for most foundries and not one that should be taken lightly. A lot of pressure is put on the entire method of operation when the change is made to continuous burnout and preheat.

 

   Continuous operation is best suited to that foundry that has a large quantity of identical or similar size shells on a regular basis. All of these molds must see the same time and temperature, so it is not conducive to a job shop situation that has a wide variety of shells that require different burnout and preheat profiles. Combine this with scheduling and timing of melting, and possible different metals, and you begin to see the impact that continuous shell processing can have on your operation. Batch furnaces provide a tremendous amount of flexibility.

 

   On the positive side, continuous operation is the only real way to be sure that each mold sees the same process condition. This is one of the fundamental ways to repeatability. It also reduces labor, time and process steps (equipment). For a complete analysis of whether you are suited for continuous burnout and preheat operation, call us for a visit by your Pacific Kiln Representative. - The Pyro Maniac

 

 

 

NEW PRODUCTS

   Nearly all foundries in the Investment Casting Industry have a common problem that can cause significant difficulties in controlling the variables of the casting floor. Let's face it, the casting area is a hot place and requires ventilation to keep the employee at least a little comfortable.

 

   So, fans and doors are at the employees' disposal to moderate the climate they work in. In the morning, the doors might be closed and the fans off. As the day warms up, the doors might open and then later the fans are turned on, or visa versa. Wind as well as extreme cold and heat can also have an effect. This creates an infinite set of variables that all have an effect on the ambient pressure inside the casting room. As this pressure changes, it directly affects the performance of the FlashFire Dewax, burnout and preheat furnaces that process the shells for pouring. This ambient pressure can rapidly change from positive to negative, back and forth, as the employee seeks comfort.

 

   FlashFire Dewax, burnout and preheat furnaces are at peak performance while operating at neutral to slightly negative pressure in the load area. Positive pressure can cause smoke and heat to push out through car and door seals, setting up possible damage, emissions and unsafe working conditions. Negative pressure can create uneven heat distribution, slow heat up and recovery, and create excessive velocity in the afterburner stack, causing emissions.

 

   Pacific Kiln recently developed and introduced an Automatic Pressure Damper that maintains the proper furnace pressure amid the inevitable changes in ambient conditions. This system is an addition to the end of the chimney stack and constantly adjusts the damper as it reads the load area pressure. It is just another variable eliminated in the quest for perfect repeatability. The Automatic Pressure Damper is available as an option on new furnaces and as a retrofit package for existing furnaces. And, it is simple to install and operate. If the conditions described above ring a bell, and we bet they do, give us a call. We have a fix.