A vessel which collects and discharges liquid by alternately pressurizing and depressurizing through a given valve arrangement, utilizing a secondary, compatible vapor or gas pressure as the motive force. The purpose of an SPD is to transfer a liquid from point A to point B using a vapor such as steam, air, or a compatible inert gas under positive pressure to push the liquid out of the vessel and into the discharge line. SPDs are used most commonly to collect and pump steam condensate.
Type 1
Type 2
