Reader Feedback on Gas Bottles

Larry Boulden
June 03rd, 2008.

We’re always happy when a reader takes the time to write about one of our feature articles.  So we were pleased to hear from Wayne Baldridge when he saw one way to improve a recent article on using gas bottles to supplement hydraulic accumulators.

Wayne wrote, “ Nowhere in the article was there a ‘reason’ given.  

“The gas volume has an initial pressure which the incoming fluid must exceed in pressure to displace or assume the space. As the volume decreases, the pressure increases. The initial pressure and the pressure at fluid volume determine the useful volume of the accumulator as defined by working pressure. 

“At half fluid volume the pressure must be 2X of the initial pressure. What the backup gas does is reduce the compression change of the gas so that the accumulator empty pressure and the full pressure are closer together. Working pressure then need not change as much to exchange fluid in the accumulator. 

“A stand alone accumulator requires a working pressure change of 2X to access ½ of its volume. With a back-up gas bottle, that pressure change can be substantially less to access the accumulator’s full volume.  

“For what it’s worth.  Wayne.”

You can read the article, “Reduce hydraulic accumulator cost with backup gas bottles” in the current (May 08) issue of Design World, or on this website.  Take a look, then let us know what you think.

–Larry B