Objectives

Our customer’s miniature or “micro” gas turbine powered electric generation systems typically feature a high-speed electric alternator, mounted directly on the turbine shaft, a high current inverter/rectifier system, and heat recovery system or recuperator. The system produces clean power in the 30 kw to 200 kw range, and heat that can be used for secondary processes or absorption cooling, when coupled to the heat recovery generator. They needed a custom fuel metering pump to meet the needs of their engine design.

 

Solutions

Cascon’s liquid fuel metering pump consists of a rolling contact, positive displacement pump rotor (known as an IGR), with an integral brushless dc drive motor and digital electronic controller. The fuel pump is capable of precisely metering fuel over a turn down ratio of up to 50:1. Output flow is proportionally controlled with a 0-5 VDC input command signal to the digital motor controllers. Accurate speed feedback is provided by a square wave output signal generated by a Hall Effect switch embedded in the winding of brushless dc motor. The wetted components are hermetically sealed from the motor windings and control electronics, thus eliminating concerns of fluid leaks normally associated with conventional shaft seals. The pumping chamber consists of a tool steel rotor assembly housed in a nickel plated cast iron eccentric ring, with nickel plated cast iron top and bottom port plates.

 

Select Performance Data

Fluids: Jet-A, JP-4, JP-10, K-1, Diesel
Metering Flow Range: 20 cc/min – 1000 cc/min
Discharge Pressure: 100 psig max
Flow Metering Accuracy: +/- 2 %
Temperature Range: -40 °C to +160 °C
Transient Response: Min to Max in < 80 msec
Operating Voltage: 12 – 28 vdc (24 vdc nom)
Relief Valve: Integral – bypass to inlet
Construction: Semi-hermetic, canned rotor
Design Life: 20,000 hours continuous duty