A valve assembly , comprising: a seat plate having a top surface and a bottom surface ; a plurality of first valve modules arranged in a first level relative to said seat plate such that a first seating face of each of said plurality of first valve modules is substantially co-planar with a first plane that is substantially parallel to at least one of said top surface and said bottom surface of said seat plate ; wherein each of said plurality of first valve modules comprises a first portion having a first lateral width and a second portion having a second lateral width that is less than said first lateral width , said second portion being positioned below said first portion , such that at least a first part of said first portion of each of said plurality of first valve modules at a first side of said first portion is offset from and overhangs a corresponding first side of said second portion ; and at least one second valve module arranged in a second level relative to said seat plate such that a second seating face of said at least one second valve module is co-planar with a second plane that is substantially parallel to said first plane , wherein said second plane is offset from said first plane by a first distance , wherein said second portion of at least a first one of said plurality of first valve modules is nested with said at least one second valve module such that: said first side of said second portion of said first one of said plurality of first valve modules is positioned proximate a second side of said at least one second valve module ; and said overhanging first part of said first portion of said first one of said plurality of first valve modules is positioned above at least part of said at least one second valve module ; and wherein the first and second valve modules are reed valve modules. a seat plate having a top surface and a bottom surface ; a plurality of first valve modules arranged in a first level relative to said seat plate such that a first seating face of each of said plurality of first valve modules is substantially co-planar with a first plane that is substantially parallel to at least one of said top surface and said bottom surface of said seat plate ; wherein each of said plurality of first valve modules comprises a first portion having a first lateral width and a second portion having a second lateral width that is less than said first lateral width , said second portion being positioned below said first portion , such that at least a first part of said first portion of each of said plurality of first valve modules at a first side of said first portion is offset from and overhangs a corresponding first side of said second portion ; and at least one second valve module arranged in a second level relative to said seat plate such that a second seating face of said at least one second valve module is co-planar with a second plane that is substantially parallel to said first plane , wherein said second plane is offset from said first plane by a first distance , wherein said second portion of at least a first one of said plurality of first valve modules is nested with said at least one second valve module such that: said first side of said second portion of said first one of said plurality of first valve modules is positioned proximate a second side of said at least one second valve module ; and said overhanging first part of said first portion of said first one of said plurality of first valve modules is positioned above at least part of said at least one second valve module ; and wherein the first and second valve modules are reed valve modules. <EOS>