Provided is a liquid pump configured to suppress discharge of air from an air pool formed in a discharge-side tank. A discharge-side tank part formed in a housing has a first inner wall surface and a second inner wall surface facing each other in a horizontal direction in an installed position of the liquid pump. The first inner wall surface is formed with a discharge port, and the second inner wall surface is formed with an opening of a discharge-side communicating passage. An air pool is formed in a space in the discharge-side tank part above the opening of the discharge-side communicating passage and the discharge port. A circular cylindrical partition is provided in the discharge-side tank part. The circular cylindrical partition projects from the second inner wall surface toward the first inner wall surface with at least a portion of the cylindrical partition positioned above the opening of the discharge-side communicating passage so as to cover the opening as seen from the air pool side.

An air pump is provided. An air pump includes an upper cover, a valve seat, a spacer, an air intake one-way valve and a piston assembly. The upper cover has an air outlet. The valve seat is disposed on a bottom of the upper cover. The spacer is disposed between the valve seat and the upper cover and has an air intake chamber and an air outtake chamber. The air intake chamber has an air intake passage communicated therewith, and the air outtake chamber having an air outtake passage communicated therewith. The spacer has a valve clack, so that air flows in a one-way direction from bottom to top. The air intake one-way valve is disposed and movable in the air intake passage so as to make the air flow in the one-way direction from top to bottom. The piston assembly is disposed under the valve seat.

A valve assembly for a diaphragm pump reduces leakage while providing good flow-through by including shaping of the seat and/or the valve that increases the elastic tension between the valve and seat in outer regions of the valve assembly, thereby providing a more optimal tension over the entire valve. In embodiments, outer regions of the seat are more steeply sloped upward than inner regions while the valve is substantially uniform in slope. In other embodiments, valve outer regions are less steeply sloped upward, or more steeply sloped downward, than its inner regions, and the seat is substantially uniform in slope. A vertical cross section of the seat and/or valve can include continuous curvature and/or discrete changes in linear slope. In some embodiments, two linear slopes are included in the vertical cross section of the seat or valve. The pump can be a multi-chamber pump.

A diaphragm pump has at least one pump chamber, the pump chamber being connected to an inlet chamber via an inlet valve and to an outlet chamber via an outlet valve. The inlet valve has an inlet opening which can be closed by an inlet valve body, and the outlet valve has an outlet opening which can be closed by an outlet valve body. The outlet opening surrounds the inlet opening, or the inlet opening surrounds the outlet opening.

A volume pump transfers a transfer fluid by expanding and contracting a bellows, and includes: the bellows that is capable of expanding and contracting, and has a bottomed cylindrical shape forming a pump chamber on its inside; a suction valve provided on a suction side of the pump chamber to guide the transfer fluid into the pump chamber; and a discharge valve provided on a discharge side of the pump chamber to discharge the transfer fluid from the pump chamber. The suction valve and the discharge valve each include a valve seat and a valve body. The valve body is configured from a flexible material and has: a fixed section whose positional relationship with the valve seat is fixed; and a valve section that extends in a certain direction between a direction directed from the fixed section to the valve seat and a direction that the transfer fluid moves.

A pump device and method for stabilizing a suction flow rate irrespective of an outside air temperature. The method includes: outputting a drive signal for driving a motor at a rotation speed for discharging gas of the reference flow rate from the suction port of the pump main body; measuring a temperature of gas discharged from the suction port or a temperature of the pump main body by a temperature sensor attached to the pump main body; calculating an actual flow rate of the gas discharged from the suction port based on a temperature signal relating to the temperature of the gas included in an output of the temperature sensor; and correcting the drive signal such that the actual flow rate equals the reference flow rate and outputting the corrected drive signal to the motor.

A diaphragm pump converts rotation of a motor into a reciprocating motion and drives a diaphragm. The diaphragm pump includes a partition configured to form a pump chamber together with a deformation portion of the diaphragm, a suction passage communicating with the pump chamber via a suction through hole extending through the partition, and a suction valve configured to open/close the suction passage. The valve body of the suction valve includes a leak structure configured to form a channel between the valve body and the seat surface of the partition.

The invention relates to a valve assembly for a diaphragm pump, the valve assembly having an inlet side and an outlet side. A first outlet channel (23) leads from an inlet opening (24) arranged on the inlet side to an outlet opening (25) arranged on the outlet side, and a second outlet channel (26) leads from an inlet opening (27) arranged on the inlet side to an outlet opening (28) arranged on the outlet side. An inlet channel (30) has a first part (31) and a second part (32), the second part (32) having an outlet opening (33), which is arranged on the inlet side, and the first part (31) extending at an angle to the second part (32). An inlet valve body (40) is provided at the outlet opening (33) of the second part (32) of the inlet channel (30), and a first outlet valve body (41) is provided at the outlet opening (25) of the first outlet channel (23). The outlet opening (28) of the second outlet channel (26) is closed and opened either by a second outlet valve body or also by the first outlet valve body (41).

A diaphragm pump and a valve system each include a valve plate having a planar valve engaging surface, a plurality of planar valve seats formed in the valve engaging surface, and a hole extending through each of the valve seats to an opposite face. Valves are disposed in the valve seats. Each of the valves includes a stem having a longitudinal axis extending through an associated one of the holes, and a flap at a first end of the valve extending transversely to the longitudinal axis. The stem and the flap have a non-circular cross-section, and a width of the flap and stem transverse to the longitudinal axis is greater than a depth of the flap and stem transverse to the longitudinal axis along the valve.

A diaphragm pump for a bioprocess system comprises a pump head (1; 101; 201; 301) comprising: a common inlet (3); a common outlet (5); a plurality of pump cavities (7) each including at least one cooperating pair of one-way valves, the at least one pair of one-way valves including an inlet valve (9) and an outlet valve (11), wherein the respective inlet valves (9) are in fluid communication with the common inlet (3) and the respective outlet valves (11) are in fluid communication with the common outlet (5) and wherein a centre of the outlet valve (11) for each pump cavity is positionable above a centre of the inlet valve (9) for the same pump cavity when the diaphragm pump is oriented for use to inhibit trapped gas; and a plurality of moveable diaphragms (13) each respectively provided in a respective of said pump cavities (7) for varying a volume of the pump cavities. The system further comprises a pump drive (31) which is configured to transfer a motion to the diaphragms (13) of the pump head (1; 101; 201) for accomplishing a fluid displacement from the common inlet (3) to the common outlet (5) of the pump head (1; 101; 201; 301) as a result of said varying of the volume of the pump cavities (7).