1. Field of the Invention
The present invention relates to a system for compressing gas, particularly combustible fuel gas.
2. Prior Art
With the increasing expense and scarcity of liquid fuels, more effort is being concentrated on developing use of less expensive and more readily available gas fuels. For example, vehicles have been modified to run on natural gas or propane.
Gas fuels, of course, occupy a large volume unless they are stored at high pressure. In the example of modified vehicles, even when large bulky fuel tanks are provided the vehicles usually have limited ranges. If gas fuels could be compressed economically and stored at higher pressures, the popularity of the modified vehicles almost certainly would increase because of the increased ranges of the vehicles.
There are problems in compressing gas fuels to high pressures with conventional, mechanically driven, gas-compressing equipment. The gas fuels tend to promote corrosion and wear and, particularly at higher pressures such as 1500 psi or higher, all but the most durable materials used for cylinders, mechanically-driven pistons, valves, seals, and so on, tend to wear quickly. Consequently, conventional equipment capable of compressing gas fuels to high pressure is expensive to manufacture and maintain.
In addition, as components of the conventional gas-compressing equipment become worn, there is an increased risk of air leaking into the compression chambers. Compressing the air heats it, increasing the risk of an explosion or fire.