This article was originally published in the April issue of COMPRESSORtech2. Get every issue in your inbox/mailbox and access to our digital archives with a free subscription.
Harsco Industrial Air-X-Changers (HAXC) is not sitting still, recently completing its new manufacturing facility in Tulsa, Oklahoma. The company’s roots date to 1952, the pioneering days of the gas compression air-cooler industry, when oil-patch engineer Murray Carr established Carr Engineering Co. Carr’s rating process replaced the trial-and-error approach to cooler sizing and design that had been used up to that time. His company was incorporated as Air-X-Changers in 1954 and many more innovations followed. In 1958, the model EH was introduced. This compact, forced-draft vertical discharge air-cooler, that combined engine and compressor cooling in a single package, has become the most widely used cooler style in the gas compression industry.
In 1961, the company pioneered the high-efficiency WheelFin design that increased the heat transfer capability and reduced the required heat transfer area of the finned tubes used in air-coolers. In 1969, the patented model F cooler was introduced, featuring multiple engine-driven fans, each with its own plenum chamber, in a design that reduced installation costs and maximized performance.
Air-X-Changers became a unit of Harsco Corp. in 1976 and continued to progress and grow over the ensuing decades. The patented model FI cooler was introduced in 1982. In 1995, the company became one of the first air-cooler manufacturers to earn ISO-9001 designation. Eight years later, Harsco patented an ASME-certified formed header design. Rebranded as Harsco Industrial Air-X- Changers in 2010, the company received the A-1 Level Manufacture License of Special Equipment required for the shipment of its products into China, and it expanded joint venture operations into Australia.
In 2011, a new leadership team, led by Eric Clower, vice president and general manager, came onboard, bringing with them experience in aerospace, marine and other industries. This new team would be responsible for the major company wide transformation.
“Over the past six years, tremendous growth has resulted from capital investment in plant and leading edge technologies that ensure the company’s continued preeminent position,” Clower said. He said that one of the most far-reaching developments is HAXC’s implementation of Six Sigma and Lean Manufacturing to maximize customer value. In addition to implementing a continuous improvement program, developing a culture of safety, and rejuvenating product research and development, the company has completed significant expansions in product lines and facilities.
In 2014, HAXC acquired Hammco, an Owasso, Oklahoma-based manufacturer of air-coolers used in the midstream compression, natural gas processing, oil refining, LNG and petrochemical industries. “Historically, HAXC has been the leader in air-coolers for compressor applications,”Clower said. “With the purchase of Hammco, we immediately became a major player in the high-spec cooler markets as well. And with our manufacturing and process improvements, we can now build low-spec and high-spec air-coolers side-by-side in the same facility.”
In April 2014, operating in five different manufacturing facilities scattered around the Tulsa area, HAXC announced the consolidation of operations into a single-campus, 557,300 sq.ft. (51,776 m2) facility in Tulsa, Oklahoma. This involved a combination of demolition and massive renovation of a former Ford glass plant to create a new, efficient air-cooler manufacturing facility.
“In addition to doubling our office space and increasing shop space by 62%, this move had the significant benefit of combining all of our operations under one roof with optimized and efficient material flow and processes,” Clower said. By mid-2015, the company was already shipping units from the new facility, and move-in operations were completed by the end of 2015 with the inclusion of the Hammco operations. HAXC also collaborated with the cities of Broken Arrow, Oklahoma, and Tulsa to construct a new road to deliver its coolers from the plant without impacting traffic.
A culture of continuous improvement is evident throughout the business and the new facility, from the office to the shipping department.
“We are very data-driven, using metrics and charts to understand trends and to identify problems and opportunities to improve the business,” Clower said. SQDC (safety-quality-delivery-cost) boards are prominent in each department throughout the company. He said that each department is challenged to measure what is important, but not be a slave to the measurement process. The leadership team conducts regular Gemba walks through the facility, working together with area team members to address real problems and implement improvements.
The layout of the new facility has been well thought out. Material for cooler structures, headers and fin tubes is delivered at one end of the plant and flows through various machining, welding and forming processes to create finished components. Cooler structures and sections enter the final assembly area where they are assembled and painted before shipment from the other end of the plant.
The process begins with coolers being designed with six base 3-D CAD models using HAXC’s proprietary “smart modeling” system that allows entering data only one time. This reduces the risk of mistakes and speeds the processing of orders. Drawings and data can be produced within hours for final engineering review prior to being released for production. Thermal rating is unique to each application. The system is flexible and adaptable to accommodate HAXC and customer specifications for structure options and finishes. The engineering team provides project management, design engineering, drafting and research and development support. Its software tools include DraftSight 2011 and SolidWorks 2013 CAD modeling along with ANSYS CFX/NLT, SolidWorks Simulation, STAAD Pro and HTRI Rating for thermal and structural analysis.
Cooler headers are fabricated in a 78,000 sq.ft. (7247 m2) code welding section of the facility with ASME-certified welders working in individual-screened booths in a high bay with cranes and ventilation systems. CNC and conventional drilling machines accommodate lengths up to 20 ft. (6 m) in length. Welding capabilities include plain carbon steel, 304 and 316 stainless, duplex, super duplex, Hastelloy, Inconel, Monel, 1.25% chrome alloys and other materials. Multiple single, dual and quad head subarc welders are used. On-site nondestructive testing (NDT) capabilities include liquid dye penetrant, wet and dry magnetic particle, ultrasonic and radiography (in two separate vaults).
Twelve operational finning machines, with tube length capabilities up to 64 ft. (19.5 m) specialize in tension-wound L-footed WheelFin on 0.625 to 2 in. (16 to 51 mm) diameter tubes. The company has several more finning machines in storage that can be quickly deployed if capacity expansion is needed. In-house capabilities include plain and embedded fin. Extruded and welded fin designs are also available. Tube materials include carbon steel and 304 and 316 stainless steels. Semi-automated and manual tube-to-tube sheet welding are employed in the construction of cooler sections up to 100 ft. (30.5 m) or longer. Extensive flushing capacity is available for turbine lube oil coolers and other applications that require extreme cleanliness. Clower said that the company’s flushing technology and equipment gives them the largest lube oil flushing capacity worldwide.
The cooler structure fabrication department includes a full sheet metal fabrication shop with brake presses to 750 tons (680 tonnes); shears with capacity for plates up to 0.625 in. (16 mm) thick by 16 ft. (4.9 m) long; multiple iron worker stations up to 100 tons (907 tonnes); a pyramid plate roll; horizontal and vertical saws; two 20 ft. (6.1 m) CNC bed plasma cutters; 29 GMAW pulse arc welding stations; and two dedicated paint booths.
A 110,000 sq.ft. (10,220 m2) area is dedicated to finished cooler unit assembly. It has a 90 ton (82 tonne) maximum lift capacity with 34 ft. (10.4 m) clear height that can handle widths of up to 30 ft. (9.1 m). Finish painting is completed in two large downdraft paint booths. At the end of the assembly department are six loading docks with space for indoor trailer loading using overhead cranes.
HAXC’s quality system certifications include ISO 9001 and ASME U and R. As of January, HAXC passed a milestone of 99,000 ASME-certified cooler sections shipped and will surpass 100,000 this spring. The company has had a Chinese manufacturing license since 2009 and it can manufacture products adherent to European Pressure Equipment Directive (PED), GOST (Russia) and ATEX standards.
“HAXC serves compression markets from gas gathering through transmission, as well as midstream processing and other markets including refinery, LNG, petrochemical and power generation,” said Randy Benson, vice president of sales and marketing. The HAXC air-cooler product line is made up of six different models. “Larger units with fan sizes of more than 72 in. (1829 mm) are HAXC’s prevalent business, but we also make a high volume of smaller coolers. The 144 to 168 in. (3658 to 4267 mm) model EH is our bread and butter line.”
The forced-draft model EH, the most widely used type, is a compact, unitized engine-driven cooler that combines engine and compressor cooling in a single unit. It can also be electric motor-driven. The sloped section arrangement with vertical discharge provides greater cooling capacity within a given footprint, which reduces packaging costs. Fan diameters from 24 to 168 in. (610 to 4267 mm) typically match cooling requirements for compressors from 100 to 2000 hp Model Z and Hammco are bolt-together horizontal coolers designed for high-power applications. Available in single or multifan configurations to span a wide range of power requirements, they are typically electric motor-driven, but can accommodate other drives including hydraulic motors and variable speed drives. Forced or induced draft fan diameters from 48 to 204 in. (1219 to 5182 mm) cover compression applications typically from 500 to 10,000 hp (373 to 7457 kW). These coolers can also be built to API 661 specifications for refinery, LNG and petrochemical industry applications. The largest HAXC air-cooler shipped in company history was a 75 ft. x 25.9 ft. x 14 ft. (22.9 m x 7.9 m x 4.3 m) model 204-3Z for offshore natural gas compression in 2013.
Model H is a skid-mounted, horizontal cooler used in a variety of applications, designed for electric motor or hydraulic drives. Available in forced or induced draft fan diameters from 24 to 144 in. (610 to 3658 mm) in single or multifan configurations, this model accommodates compression applications typically from 100 to 2000 hp (75 to 1491 kW). They are also applied to turbine oil cooling applications.
Model F is a horizontal coil, multiple vertical fan cooler. With its patented forced draft vertical air discharge design, it is designed for high power, engine-driven applications. Available in single or multifan configurations, with fan diameters from 48 to 156 in. (1219 to 3962 mm), it typically covers compression applications from 250 to 4500 hp (186 to 3356 kW).
Model VI is a vertical discharge, induced draft cooler that combines engine and compressor cooling in a single unit. Adaptable for both engine-drive and electric motor drive, with fan diameters from 36 to 168 in. (914 to 4267mm), it accommodates compression applications from 100 to 600 hp (75 to 447 kW).
Model VV is designed to be a cost-effective solution for low power gas, water and lube oil cooling. It can be either engine- or motor-driven. With forced or induced draft fan diameters from 18 to 60 in. (457 to 1524 mm), this horizontal airflow model accommodates compression applications typically from 60 to 250 hp (45 to 186 kW).
The most recent example of HAXC’s product innovation is a patent-pending design that mounts the engine exhaust silencer inside the air-cooler structure. The vast majority of compressor packages have the engine exhaust silencer mounted on top of the cooler, which typically requires a walkway or permanent work platform on top of the cooler for inspection and emissions testing. These items interfere with airflow and typically require disassembly for shipping, followed by reassembly in the field. The new HAXC design eliminates this need and includes a retractable work platform. It also enables factory mounting of the engine cooling system surge tank on the cooler frame.