Need to add that you don't want to use much pressure to operate an elephant's head.? You don't want to split the seams of your container, destroy your expensive oak barrel or break your carboy if it contains wine.? It doesn't take too many square inches of surface area to add up to a lot of force, even with a relatively small pressure differential.? I always thought about that as I was pumping processing chambers down to very low pressures.? Thousands of pounds of force were applied to the doors of some of them.? The largest tool I personally operated had close to 2,000 pounds holding the chamber door closed....
