A diaphragm compressor is a variant of the classic reciprocating compressor with backup and piston rings and rod seal. The compression of gas occurs by means of a flexible membrane, instead of an intake element.
The back and forth moving membrane is driven by a rod and a crankshaft mechanism. Only the membrane and the compressor box come in touch with pumped gas. For this reason this construction is the best suited for pumping toxic and explosive gases. The membrane has to be reliable enough to take the strain of pumped gas. It must also have adequate chemical properties and sufficient temperature resistance. A diaphragm compressor is the same as a membrane compressor. The prototype alternative fueling station was built in compliance with all of the prevailing safety, environmental and building codes in Phoenix to demonstrate that such fueling stations could be built in urban areas.
In the ionic liquid piston compressor many seals and bearings were removed in the design as the ionic liquid does not mix with the gas. Service life is about 10 times longer than a regular reciprocating compressor with reduced maintenance during use, energy costs are reduced by as much as 20%. The heat exchangers that are used in a normal piston compressor are removed as the heat is removed in the cylinder itself where it is generated. Almost 100% of the energy going into the process is being used with little energy wasted as reject heat.
The Gas Compression System:
The gas compression system consists of three flat metal diaphragms, which are clamped between two precisely contoured cavity plates, and process gas inlet and outlet check valves.
The Diaphragm Sealless Compressor System:
Check valves: Ball, poppet, or plate check valves are specified to match operating conditions and process gas. Valves are readily accessible for inspection, repair, or replacement, and can be removed without disassembly of the compressor head.
Hydraulic inlet check valve: Contains the injected hydraulic fluid within the head assembly. Valve body is stainless steel. Ball is tungsten carbide.
Hydraulic pistons: For design pressures to 3000 psi (200 bar), pistons are sealed with high-quality cast iron or filled-plastic piston rings in a hardened, honed sleeve. For higher pressures a packless, ringless piston is lap-fitted to a hardened, honed sleeve; the hydrodynamic film between the two provides the lubrication and the pressure seal.
Hydraulic overpump valves: Controls the pressure of the hydraulic system. The combined movement of stem, ball, and spring determines the pressure range of the valve. Valve body is carbon steel. Seat and stem are hardened tool steel.