Three speed fluid flow control valve

A control valve for series connection in a fluid flow control line in which alternating fluid flow in opposite directions at different speeds is desired and with the fluid flow in one direction being allowed at a substantially constant high rate and the fluid flow in the opposite direction is initially allowed at generally the same rate and is thereafter gradually throttled to a slower flow rate, said valve including a body having a main flow passage therethrough and a by-pass passage therein by-passing a central portion of said main flow passage, throttle means operative to adjustably throttle the fluid flow rate through said by-pass passage, and control valve means in said main flow passage central portion supported from said body for shifting between open and closed positions allowing fluid flow therepast at a rate slightly slower than said high rate in said one direction and at least substantially terminating fluid flow therepast in said closed position, means yieldingly biasing said control valve to said open position, said control valve including a fluid impact portion disposed in said central portion of said main flow passage for fluid impact pressure thereon to shift said control valve toward said closed position against said means biasing said control valve toward said open position, and adjustable rate movement dashpot means operatively connected between said body and control valve operative to vary the closing rate of said control valve.