Double diaphragm pump with controlling slide valve and adjustable stroke

A double-acting, pressurized fluid-actuated double diaphragm pump for fluids and the like, said pump including:

• (a) a main pump housing support adapted for mounting to a support means;
• (b) a first pump housing means attachable to said main pump housing support, the first housing means including inner and outer diaphragm housing members with the outer members having inlet and outlet valve means providing one-way flow control of the pumped fluid;
• (c) a first diaphragm interposed between said inner and outer housing members and means for securing the diaphragm at its outer periphery in a fluid tight manner;
• (d) a second pump housing means attachable to said main pump housing support, said second housing means including inner and outer diaphragm housing members with the outer member having inlet and outlet valve means providing one-way flow control of the pumped fluid;
• (e) a second diaphragm interposed between the inner and outer diaphragm housing members and means for securing said second diaphragm at its outer periphery in a fluid tight manner;
• (f) a reciprocable rod connecting the central portion of the first and second diaphragms and as one diaphragm is moved outwardly to provide an expelling actuation the other diaphragm is moved inwardly to provide an intake actuation, said rod secured at its ends to central portions of the diaphragms and with the rod carried in and by bearing means provided in the main pump housing;
• (g) a pressurized fluid inlet connecting means adapted to receive the pressurized fluid from an external source and deliver said fluid to a control system including conduit means;
• (h) a slide valve associated with the main pump housing and including a housing and a spindle reciprocable to two limits of movement in a finished bore of regular diameter formed in said housing, said spindle having reduced diameter areas interposed between four seal ring areas, each ring area adapted to restrict flow of pressurized fluid along said bore;
• (i) means for sealing the ends of the finished bore so that pressurized fluid does not escape from said bore as the spindle is moved therein;
• (j) a pair of arm member means carried on and movably secured to the reciprocable rod as it is cycled;
• (k) a pair of pilot valves each carried in a bore in a boss portion provided within the main pump housing, each of said pilot valves arranges as a mirror pair and having a shaft within said pilot valve and with an extending end disposed to be engaged and moved by an arm member means, each of said valves having a bias means adapted to urge the shaft toward the central portion of the main housing, said pilot valves additionally having a pair of spaced disk portions adapted to alternately engage rib portions disposed between inwardly facing portions carried by the shaft of the pilot valve and with these disk portions adapted to be alternately brought into engagement with the rib faces so as to shut off fluid flow to and from the interior of the pilot valve and with each pilot valve providing conduit means disposed between the ribs;
• (l) a conduit from the inner side of the diaphragm chamber and to a position adjacent the inlet of pressurized fluid from the source and to the spindle reduced area;
• (m) a conduit from the diaphragm chamber and through the pilot valve and to the conduit means between the ribs of a pilot valve, and
• (n) a discharge conduit from the main pump housing, whereby pressurized fluid is fed to the inlet thence to the reduced area of the spindle intermediate its ends and between the second and third seal ring areas and with the spindle at its left position the pressurized fluid between the second and third seal ring areas flows therefrom to the inner side of the first diaphragm to provide a pumping actuation, and the first pilot valve is closed to pressurized fluid flow from the first diaphragm chamber and pressurized fluid flows from the reduced area of the spindle between the third and fourth seals and exterior of the fourth seal to and through the second pilot valve and from this pilot valve to and through the discharge conduit in the main pump housing, and when the first pilot valve is actuated by the first arm member pressurized fluid flow is reversed as to the first pilot valve and pressurized fluid from the diaphragm chamber and the first pilot valve is caused to flow into the closed bore exterior of the first seal to move the spindle to the other limit of motion to uncover a passageway to the second diaphragm and pressurized fluid enters the second diaphragm chamber and moves the diaphragm to a pumping actuation and this actuation is reciprocably and alternately made in response to actuations of the pilot valves and their actuation by said arm members.