Air compressor with inlet diversion valve

A compressor having an inlet port communicating with a pressurized gas source, a compressor inlet valve communicating with said inlet port, a governor and unloader for unloading said compressor by maintaining said inlet valve open, diversion valve means between said inlet port and the pressurized gas source for blocking communication of the pressurized gas source with said inlet valve through said inlet port when said governor and unloader operate to maintain said inlet valve open, said diversion valve means including a valve body having generally oppositely located gas source and governor ports respectively communicating with said pressurized gas source and with said governor, said valve body having supply and vent ports located intermediate said gas source and governor ports and respectively communicating with said inlet port and with atmosphere, said diversion valve means including mounting means for mounting same directly to said compressor with said supply port in direct communication with said inlet port, a movable valve member in said valve body and including an enlarged main body portion and a smaller extension portion, said valve member being movable between a first position wherein said main body portion closes said vent port while establishing communication directly therepast between said gas source and supply ports and a second position wherein said main body portion closes said gas source port while establishing communication directly therepast between said supply and vent ports, said movable valve member in both said positions thereof maintaining said governor port isolated against communication with the other of said ports, yieldable biasing means acting directly on said main body portion of said valve member for normally biasing said valve member to said first position, said valve body having a cylindrical bore defining a variable volume chamber communicating with said governor port and including a variable volume chamber wall, said extension portion of said valve member being positioned in said chamber in sliding sealing engagement with said wall for movement of said valve member to said second position by fluid pressure supplied to said variable volume chamber through said governor port.