Diaphragm pump

A diaphragm pump assembly comprising:

• an assembly inlet;
• an assembly outlet;
• a first pump chamber positioned in a first fluid path between the assembly inlet and outlet;
• a second pump chamber positioned in a second fluid path between the assembly inlet and outlet;
• a first diaphragm positioned at least partially within the first pump chamber at a rest position, the first diaphragm having a perimeter sealingly connected to one or more walls of the first pump chamber;
• a second diaphragm positioned at least partially within the second pump chamber at a rest position, the second diaphragm having a perimeter sealingly connected to one or more walls of the second pump chamber;
• a first piston connected to the first diaphragm, the first piston movable linearly;
• a second piston connected to the second diaphragm, the second piston movable linearly;
• wherein:
• movement of the first piston toward the first pump chamber forces a portion of the first diaphragm to move from its rest position to a position further within the first pump chamber and to increase pressure in the first pump chamber;
• movement of the first piston toward the first pump chamber forces a portion of the second diaphragm to move from its rest position to a position away from the second pump chamber and to reduce pressure in the second pump chamber;
• movement of the second piston toward the second pump chamber forces a portion of the first diaphragm to move from its rest position to a position away from the first pump chamber and to reduce pressure in the first pump chamber;
• movement of the second piston toward the second pump chamber forces a portion of the second diaphragm to move from its rest position to a position further within the second pump chamber and to increase pressure in the second pump chamber;
• a first check valve positioned in a fluid path between the assembly inlet and the first pump chamber, the first check valve configured when in an opened position to permit fluid flow from the assembly inlet into the first pump chamber and when in a closed position to inhibit fluid flow from the first pump chamber toward the assembly inlet;
• a second check valve positioned in a fluid path between the first pump chamber and the assembly outlet, the second check valve configured when in an opened position to permit fluid flow from the first pump chamber toward the assembly outlet and when in a closed position to reduce fluid flow from the assembly outlet into the first pump chamber;
• a third check valve positioned in a fluid path between the assembly inlet and the second pump chamber, the third check valve configured when in an opened position to permit fluid flow from the assembly inlet into the second pump chamber and when in a closed position to inhibit fluid flow from the second pump chamber toward the assembly inlet;
• and
• a fourth check valve positioned in a fluid path between the second pump chamber and the assembly outlet, the fourth check valve configured when in an opened position to permit fluid flow from the second pump chamber toward the assembly outlet and when in a closed position to reduce fluid flow from the assembly outlet into the second pump chamber,
• wherein each check valve comprises at least one pair of a spherical ball and a seat opening, wherein for each pair, the spherical ball contacts the seat opening when in the closed position;
• wherein in the closed position, the second check valve has for each pair, a gap between its spherical ball and seat opening to provide an escape path for gas;
• wherein in the closed position, the first and third check valves have for each pair, no gap between its spherical ball and seat opening;
• and
• wherein the rest position of the first diaphragm is further within the first pump chamber and/or the rest position of the second diaphragm is further within the second pump chamber to provide a fluid flow rate as if the second check valve has for each pair, no gap between its spherical ball and seat opening when in the closed position and/or the fourth check valve has for each pair, no gap between its spherical ball and seat opening when in the closed position.