The ZVI unloader valve from Zahroof Valves is a piston-style unloader, designed to improve reliability over traditional finger style unloaders. It features a lower added clearance volume compared to plug style unloaders, according to the company.
The ZVI unloader valve can be serviced in the field without any additional machining. It is a reliable unloader as there are no fingers acting against a dynamic valve element. Unlike a plug-type unloader, there is no large increase in clearance volume in the cylinder that can detrimentally affect the compressor, according to the company. The flow through the unloader improves unloaded power and eliminates drag forces and aerodynamic flutter of valve elements. The unloaders reportedly do not have misalignment/assembly issues. The actuation force required for the ZVI unloader valve is less than for alternatives, according to the company.
Users can replace multiple existing unloader systems at a corner of a cylinder with a single ZVI unloader system, utilizing regular suction valves in the other locations. The ZVI unloader valve can reportedly be used with all compressors, at any speed, for both lubricated and non-lubricated cylinders. It can be used with virtually any gas where the maximum differential pressure across the unloader is up to1500psi, according to the company.
