Double-acting flexible tube pump

In a flexible tube pump, a pair of substantially identical pump cylinders each having inlet and outlet openings and a flexible tube in each said cylinder connected at its ends to the inlet and outlet openings thereof;

• each said connection comprising a frusto-conical recess in the cylinder wall, a hollow stem extending through said opening and having an enlarged frusto-conical head portion complementary to and juxtaposed to said recess comformably receiving the end of the tube, means for drawing said head portion toward and into said recess for compressing the end of the tube between said frusto-conical surfaces, and means on said stem for maintaining a clamping pressure on the tube end;
• a single control cylinder communicating adjacent one end thereof with one of said pump cylinders exteriorly of the respective tube and adjacent the other end thereof with the other pump cylinder exteriorly of the respective tube;
• and a single piston reciprocable in said control cylinder;
• the improvement comprising two spaced apart seals mounted in said control cylinder and sealingly engaging said reciprocable piston intermediate the two ends of said control cylinder;
• liquid having a visually detectable coloring;
• said liquid filling the pump cylinders exteriorly of said tubes and the control cylinder to opposite sides of said two seals;
• a piston rod connected to and extended from only one end of said piston and extending through only one end of said control cylinder for reciprocating said piston and displacing said liquid and thereby alternately and cyclically contracting and expanding said tubes to perform a pumping function;
• the end of said piston opposite said piston rod being unobstructed, hollow and having a larger effective piston area than the other end of said piston, said piston being of relatively large diameter in relation to the diameter of the piston rod for minimizing the differential between the effective areas of the two ends of the piston and thus the liquid displacement thereof;
• and a sight glass in communication with said control cylinder in the space therein between said two seals, whereby the liquid leaking past either seal, itself, gives a signal when it is detected in said sight glass and before it passes the other seal so that damage to said tubes is averted.