From 42 hp to 845 hp with a cylinder lineup capable of handling a wide range of pressures from vacuum to 5,500 psi, the AJAX integral engine compressor product line was designed to improve field productivity, offer maintenance and reliability, and support operators in an environment of continually evolving emissions compliance. The integral engine compressors are a userfriendly option that delivers long-term efficiency.

Many AJAX units are still in service today, having been originally released in 1958. The inherent nature of the unit’s engine and compressor has remained fundamentally unchanged since then. Improvements over the years have merely served to enhance the strength and simplicity of the original design.

In addition, operators have been able to upgrade their units with several technical and engineered enhancements. These upgrades are available as retrofit kits and maintain the simplicity that the units are known for.

Easing maintenance, improving performance

One recent upgrade has been the integrated governor throttle body (IGTB) electronic governor, which is now standard equipment on all new AJAX engines.

The IGTB is a combined throttle valve and electronic governor. Its purpose is to maintain a fixed-speed set point throughout the engine’s load range. The set point also can be externally set by a remote signal. The governor measures engine speed with a magnetic pickup and compares it to the set-point speed provided by the transducer. When engine speed changes from the desired level, the IGTB automatically adjusts fuel gas header pressure as required to maintain the desired speed.

Designed to forego the need for onsite tuning, the IGTB replaces the standard mechanical and Woodward hydraulic governor and is available on any unit. The IGTB is designed to offer high reliability, excellent speed stability and fast response to load changes. Ideal for usage with fuel gas containing H2S, the IGTB is vibration-resistant, easy to install and powered by either customer-supplied power or an engine-mounted Class I Division 2 alternator, which eliminates the need for outside power.

Increasing power and efficiency

The scavenging intake poppet valve is a bolt-on retrofit, replacing the reed strip valve plate on the power cylinders. It allows more scavenging air to the combustion chamber, which subsequently increases combustion efficiency. With this upgrade, available for DPC- 2800 series and legacy 15-in. bore engines, the result is optimized fuel consumption costs and lower operating and maintenance costs.

The compressor poppet valves upgrade delivers the highest efficiency of any valve design on the compressor cylinders. Compared to conventional plate, channel or strip valves, poppet valves are designed to offer significant fuel or horsepower savings through more efficient and reliable operation. Customers who have implemented this upgrade report payback in six to 18 months. Any legacy or current 11-in. stroke AJAX can benefit from this retrofit. Pre-lube systems are now standard equipment on current production units, offered with manual, electric or pneumatic configurations, and are available as retrofits. Various control logic is offered to accommodate permissive/custom startup sequencing. The systems increase unit dependability and product life, reducing maintenance costs as well as startup and idle time.

Lowering emissions

Meeting changing modern environmental emissions compliance without sacrificing performance is supported with retrofit upgrades that can be performed on all previous versions of the units dating back to 1958. A field-proven oxidizing catalytic converter for two-stroke low-emission gas engines has been designed to alleviate the potential worries of oil contamination and pressure spikes, virtually eliminating carbon monoxide emissions and greatly reducing formaldehyde and volatile organic compound emissions. Internal baffles and pipes are designed to silence the exhaust and protect the catalyst element. As a result of an exhaustive R&D program, the converter is available for new units as well as retrofit applications.

Low-emissions models reduce fuel consumption, increase the range of fuel gas quality and maintain NOx emissions over a wide torque range. (Source: GE Oil & Gas)

Low-emissions models

The product line’s standard model was, at the time of its introduction, the most efficient integral engine compressor available on the market. Since its introduction, low-emissions models were developed with the purpose of achieving lower emissions without the need for expensive add-ons or the use of catalytic converters. Low-emissions models reduce fuel consumption, increase the range of fuel gas quality and maintain NOx emissions over a wide torque range. The main component of the system is the ignitor assembly, which creates a high-energy ignition source, igniting a leaner mixture of fuel and resulting in lower NOx formation and cleaner exhaust. With tuning, the low emissions achieves 0.5-g NOx emissions. Screw-in prechamber shut-in pressure also is available for some legacy engines.

Ultralow emissions

The low-emissions model can achieve the same 0.5-g NOx emissions without engine tuning, offering users the ability to maximize horsepower while reducing emissions, all at an ambient temperature rating of 37.8 C (100 F), by adding an enhanced intake system, upgraded heads, pistons and a prechamber design. High-pressure fuel injection enables enhanced air/fuel mixing, while a tuned exhaust system is included as part of the air flow operation. Additionally, there are solutions to achieve 1-g NOx with just prechamber designs.

The integral engine compressors maintain a 98% or better performance consistency because they are designed for simplicity.

Oftentimes, once an AJAX unit has been purchased, regulations and requirements change over the years requiring that the unit must change with them. The cost of investing in an upgrade represents a small fraction of the cost of buying a new machine and, in most cases, pays back within a year. Operational flexibility, environmental performance and cost reduction are all critical to success. By continually developing upgrades to address these key factors, AJAX integral engine-compressors simplify operations and maximize value.

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