In order to help keep our clients’ equipment running at optimum performance, the high-speed reciprocating compressor (HSRC) business unit has developed several aftermarket initiatives over the years. As with the MOS™ compressor, this goes back to listening to what our clients had to say. And these benefits don’t just apply to Dresser-Rand® compressors – we offer upgrades for all brands of reciprocating compressors.
Three-tier Parts Stocking Program
This inventory program was developed with our authorized parts resellers to support our mutual clients’ (end users’) situations on three levels, ranging from unexpected emergency shutdowns to everyday scheduled compressor maintenance.
Our Tier 1 parts – crankshafts, connecting rods, crossheads, and oil pumps – for current and non-current compressor models are regularly stocked in several D-R parts warehouses and can be shipped at a moment’s notice, 24/7. Most of these parts support unexpected shutdowns where compressor frame damage has occurred.
Our Tier 2 parts – piston and rod assemblies, piston rods, pistons, packing cases, valves, oil pump rebuild kits, bearings, and bushings – are stocked by our authorized parts resellers for the end user, and by Dresser-Rand. This tier supports the end user’s scheduled compressor maintenance programs and unexpected shutdowns where cylinder damage may have occurred.
Our Tier 3 parts – packing and piston rings, valve plates and springs, oil filters, and seals – are stocked by Dresser-Rand, our authorized reseller and the end user to ensure typical wear parts are readily available. These parts can be air freighted, pulled directly from a local packager warehouse or taken from the end user supply located on-site. This tier supports situations ranging from planned inspections where worn parts need replacing, to minor performance issues such as broken valve elements, to a leaky gasket or o-ring. The client can have wear parts available within hours to immediately get the unit back up running.
For example, an end user in western Texas had a HOS™ unit go down unexpectedly on vibration. An investigation determined that a crosshead, piston and rod needed replacing. “The end user contacted our stocking distributor, who in turn contacted Dresser-Rand. Within 24 hours, all of the required tier 1-3 parts were on location and the unit was back up and running in less than 48 hours,” said Gary Tas, Global Sales Manager for the HSRC business unit Aftermarket Services.
Valve Performance Critical to Peak Operation
We design and manufacture our own valves from a long legacy of engineering experience – and we believe we are the only OEM in the industry that does this.
“Our engineers work through potential problems before our clients encounter them in the field,” said Steve Chaykosky, Manager of Valve Engineering at Dresser-Rand. A dynamic valve analysis (DVA) is performed for every compressor application. The comprehensive DVA software program, developed in-house, analyzes full and part-load operating conditions to maximize valve reliability and minimize horsepower and capacity losses. The need to have an engineering tool on-site so that compressor valve assemblies could be rapidly evaluated in fatigue led to the development of our valve endurance tester. This unique device provides accelerated impact and fatigue cycling of valve components at six to 10 times compressor operating speeds. “Employing this valve ‘basher’ endurance tester allows our designers to assess valve durability in the laboratory – not in the field on a client’s compressor,” added Chaykosky.
Another element of our comprehensive valve testing is the closed loop compressor test unit at our Painted Post, N.Y., U.S.A. facility that evaluates valve performance characteristics under actual conditions. The first of its kind 36 years ago, and still an industry-wide respected, robust OEM valve testing technology, this test unit can be used on a wide variety of gases: pumping process gases at speeds up to 1,200 rpm and discharge pressures up to 1,500 psig (103 barg).
Magnum® HammerHead™ Valve
When our clients told us they wanted a product to meet the compressor efficiency gap with heavier gases such as carbon dioxide, we listened. The Magnum® HammerHead™ valve maximizes compressor efficiency for high molecular weight applications such as CO2, ethylene, propane, and natural gas. Unlike other poppet valves, the HammerHead valve can be applied at high compressor speeds. And unlike plate and ring valves, it uses one element for all valve sizes, simplifying valve inventory. “This new valve is fast becoming an industry benchmark and can be applied to all brands of reciprocating compressors,” said Chaykosky.
Computational fluid dynamics and finite element analysis were used to develop the HammerHead valve’s geometry to improve flow area by as much as 60 percent. Minimal valve loss means improved efficiency. Also, the valve’s unique element design minimizes tensile stresses, resulting in long life in demanding applications. Chaykosky recalls (before the advent of the HammerHead valve) a client who was getting 90 days or less operating time from their (non-Dresser-Rand) high-speed reciprocating compressor valves. When we approached the client and suggested our Magnum® XF valve, he was willing to do a “try and buy” to see if the valves would last in 1,000 psi (69 bar) natural gas service at 1,350 rpm. He agreed that if the valves lasted at least 90 days he would buy them. The valves were in service for three years before they were removed for inspection. After inspection, the valves were re-installed because they were still in great shape. Pleased with the Magnum XF valves and confident in Dresser-Rand’s valve technology, the client ordered a set of Magnum HammerHead valves for one of his natural gas compressors (a D-R competitor’s unit) operating in 900 psi (62 bar) natural gas service at 1,380 rpm. In another instance, a client’s machines were overheating during summer months disrupting production. We installed our Magnum HammerHead valves and the client’s throughput went up and cylinder gas discharge temperatures dropped by approximately 20 degrees Fahrenheit (-6 degrees Celsius).
“As is evident in the examples above, we work closely with our clients to quickly resolve problems and continue to research better ways to manage high-speed compression. We work with our packagers, distributors and end users to ensure client support from every angle,” said Tas.