Hydrodynamic surge absorbing apparatus

Claim 1

A hydropneumatic surge absorbing apparatus for connection to a header pipe in a liquid transmission pipe system to eleviate shock and surge caused by starting and shutting down pumps having their associated outlet check valves connected to said header pipe, comprising in combination: a. a closed vessel; b. a swirl chamber having an upper tangential inlet and lower central outlet, and being in the form of an inverted truncated cone with its lower central outlet at the truncated apex of said cone and its upper tangential inlet adjacent to the inverted base of said cone such that a particle laden liquid passed tangentially into said inlet swirls around to define a vortex prior to flow out said central outlet; and c. inlet means for sealingly connecting said upper tangential inlet to said header pipe in said system through which a particle laden liquid subject to shock and surge passes, said lower outlet being positioned above, and in flow communication with a lower interior portion of said closed vessel to facilitate ingress and egress of said particle laden liquid, said lower interior portion being submerged when said vessel is partially filled with said particle laden liquid, the remaining interior of said vessel including a gas under pressure so that said particle laden liquid can move into said swirl chamber to increase the liquid level in said vessel and further compress said gas and back out through said swirl chamber to result in a lowering of the level of liquid in said vessel, the lowest level of liquid always being above said lower interior portion communicating with said lower outlet, said hydropneumatic surge absorbing apparatus being further described in that said swirl chamber construction is such that the resistance to liquid flow is in the range of from 5 to 100 times as great for liquid entering said vessel through said swirl chamber as for liquid leaving said vessel back through said swirl chamber to said header pipe.