Designed for processes engineers requiring reliable operation in the full range of high pressure services The PPI Sealless Series 4L Diaphragm Compressor is for pressures up to 16,750 psi and is a highly reliable and robust design available in several sub-series models. 4000 Single-Stage 4X000 Single-Stage 4L Two-Stage 4LX Two-Stage MARKETS Petrochemical Specialty Gas Energy R&D Partner Locator