A new high-efficiency furnace is helping a water heater manufacturing plant in Nanjing, China, dramatically increase its porcelain enameling production rates.

A water heater manufacturing plant in Nanjing, China, a port city on the Yangze River, needed to dramatically increase its porcelain enameling production rates to relieve a tremendous backlog and to manage the booming Chinese market for both commercial and residential glass-lined water heaters. The heaters range in size from 12-in. diameter x 26-in. long to 24-in. diameter x 58-in. long. The plant turned to KMI Systems, Inc., based in Crystal Lake, IL, a company that designs, engineers, manufactures and installs custom coating and paint finishing systems. The company also stocks inventory supplies and provides maintenance services for finishing systems.

KMI constructed and installed a high-efficiency porcelain enamel furnace within a 6,000 ft2 furnace room as an addition to the 383,000 ft2 water heater manufacturing plant. To date, this furnace is reportedly the largest, most efficient and modern porcelain enamel furnace in China.

Furnace Fabrication

The furnace was fabricated in the U.S. to meet specifications only possible with domestic-quality steel and to ensure overall quality control. In addition, conduit, wiring, alloy items and piping were manufactured in the U.S. to meet specifications and quality requirements. The 95½-ft-long by 16-ft-wide furnace structure was produced in modules to facilitate ocean shipping and inland transportation both state-side and in Nanjing. This construction reduces installation time and also allows for ease of expansion in the future if required. A typical U.S. installation would normally require about two to three weeks, plus an additional week for startup and training.

The gas-fired, indirect-heater, high-efficiency furnace has a 118-ft hot zone that maintains a temperature of 1600ºF. KMI Systems designed the furnace system with S type, U.S.-made inconel burner tubes; a 934-ft furnace room conveyance system; an enamel dryer oven; and a combination forced air cooling and heat transfer tunnel. The furnace will run at 11.3 to 14.5 feet per minute (fpm) in China and will produce more than 3,000 glass-lined water heaters in a nine-hour shift. The gas pressure and calorific value of the Chinese gas are lower than those in the U.S. Electrical power and voltage are also different - in China, equipment requires 480-volt primary step-down transformers to provide the correct voltage for the control and power systems. In the U.S., this same furnace line would operate at an average of 400 BTUs/U.S. lb.

Smooth Installation

Installation went smoothly, and the Chinese workers were enthusiastic about the project. KMI used a supervisory staff of two personnel over the entire installation. Several Chinese professional teams were also involved. One consisted of around 20 people and included one electrical and two mechanical crews. No automated or power equipment was used to move and erect the furnace other than fork trucks.

A number of issues make a Chinese installation different from a U.S. installation:
  • A technical English-speaking Chinese consultant is essential for a smooth installation.
  • U.S. supervision needs full-time translators.
  • Alloy material, piping, conduit, components, electrical wiring and control equipment must be imported from the U.S.
  • In this plant, the production parts are cooled with an air heat scavange tunnel, followed by a water mist section.
  • Adequate time must be built into the schedule for ocean and inland freight to China. Plants should also be prepared for large furnace modules from the port to the plant site.
  • All construction efforts are performed by manual labor.
  • Installation around the Chinese New Year adds several weeks to construction.
Despite the challenges, the U.S. corporate engineer managing the project indicated that he was pleased with the “professional installation and excellent performance of KMI’s furnace.”

For more information, contact KMI Systems, Inc. at 815.459.5255, e-mailinfo@kmisystemsinc.comor visitwww.kmisystemsinc.com.