Abstract: A method for calibrating a pressure sensor includes connecting the pressure sensor to first and second fluid storage vessels; providing an initial fluid pressure at the pressure sensor and at the fluid storage vessels; and carrying out a pressure measurement of the initial fluid pressure at a time t0. The method then disconnects the second fluid storage vessel from the pressure sensor and the first fluid storage vessel; provides a first fluid pressure at the second fluid storage vessel; and carries out a pressure measurement of the first fluid pressure at a time t1. The method then connects the second fluid storage vessel with the pressure sensor and the first fluid storage vessel, so that a second fluid pressure between the initial and first fluid pressures is provided at the pressure sensor; and carries out a pressure measurement of the second fluid pressure at a time t2.

Abstract: A power generator may generate power using buoyancy having a fluid column contained by a tank having a sealable drain and a piston having a substantially hollow interior capable of being filled with a fluid. The piston has a sealable outlet, a vent, an inlet, and a lateral cross-section that is smaller than a lateral cross-section of the tank. A rod is connected to the piston and a power generator is connected to the rod. The piston operates from a first position near the top of the fluid column to a second position near the bottom of the fluid column. The piston moves from the first position to the second position as fluid is added to the inlet. The piston moves from the second position to the first position as the fluid is drained from the outlet.

Abstract: A compressor comprising a liquid acting as piston that is displaceable in the piston compartment is described. According to the invention, a piston dummy (5) that can be displaced with the liquid (3) is arranged in the liquid. This piston dummy (5) is preferentially designed in such a manner that upon reaching the top dead centre it brings about an acceleration of the liquid (3) in the ring gap defined by said piston dummy and the piston chamber wall.

Abstract: A storage vessel is filled with compressed gas by filling a first tank with gas from a low pressure gas source. Hydraulic fluid is drawn from a reservoir and pumped into the first tank in contact with the gas. This causes the gas in the first tank to flow into the storage vessel as it fills with hydraulic fluid. At the same time, gas is supplied from the gas source to a second tank. Hydraulic fluid previously introduced into the second tank flows out to the reservoir as the second tank fills with gas. When the first tank is full of hydraulic fluid, a valve switches the cycle so that the hydraulic pump begins pumping hydraulic fluid back into the second tank while the first tank drains. The cycle is repeated until the storage vessel is filled with gas to a desired pressure.

Abstract: A method and apparatus for producing compressed air includes sealing air in a container capable of reducing its volume by external hydraulic pressure. A weight having a larger specific gravity than water is attached to the container to sink the container deep under water. Compressed air is produced when the volume of the container is reduced by hydraulic pressure, and is transferred into a recovery vessel connected to the container via a check valve. The weight is then separated from the container to cause the container to float on the water by the action of buoyancy. The compressed air can then be recovered from the recovery vessel.

Abstract: A hydraulic accumulator-compressor vessel using geothermal brine under pressure as a piston to compress waste (CO.sub.2 rich) gas is used in a system having a plurality of gas separators in tandem to recover pipeline quality gas from geothermal brine. A first high pressure separator feeds gas to a membrance separator which separates low pressure waste gas from high pressure quality gas. A second separator produces low pressure waste gas. Waste gas from both separators is combined and fed into the vessel through a port at the top as the vessel is drained for another compression cycle. High pressure brine is then admitted into the vessel through a port at the bottom of the vessel. Check valves control the flow of low pressure waste gas into the vessel and high pressure waste gas out of the vessel.

Abstract: A fluid-raising apparatus includes a compression chamber which receives liquid, from an elevated source, such that gas in the chamber is pressurized and used to lift fluid through a vertical conduit. When the chamber fills with liquid, a float lifts a drain plug so that draining commences automatically. The effluent passes through a discharge tube wherein, during draining, the liquid pushes on a piston. The piston, in turn, holds a liquid inlet valve closed until draining is complete.

Abstract: A system for converting a constant pressure head of water into compressed air which may be utilized to transfer the potential energy of the pressure head to remote work sites.