A technique for reducing harmonic vibration in a multiplex multi-pump system. The technique includes establishing a lower bound of system specific vibration-related information such as via pressure variation or other vibration indicator. Establishing the lower bound may be achieved through simulation with the system or through an initial sampling period of pump operation. During this time, random perturbations through a subset of the pumps may be utilized to disrupt timing or phase of the subset. Thus, system vibration may randomly increase or decrease upon each perturbation. Regardless, with a sufficient number of sampled perturbations, the lower bound may be established. Therefore, actual controlled system operations may proceed, again employing random perturbations until operation of the system close to the known lower bound is substantially attained.

The invention relates to a concrete pump assembly with at least two feed cylinders for conveying concrete, and at least two hydraulic drive cylinders moving the feed cylinders, wherein the drive cylinders are coupled to one another in a torsion-resistant manner via at least one connecting means. According to the invention, the drive cylinders and the at least one connecting means, in which the at least one valve is configured in an integrated manner, are formed as a drive unit that can be pre-assembled.

A trigger guard for a pendant for controlling a hydraulic power unit includes a first prong extending from a front side of a handle of the pendant; a second prong extending from the front side of the handle; a groove disposed between the first prong and the second prong, the groove defined by the first prong, the second prong, and the handle; a first gap disposed between the first prong and a head of the pendant; and a second gap disposed between the second prong and the head. The trigger is disposed between the first prong and the second prong such that the trigger is accessible through the groove, the first gap, and the second gap.

It is disclosed a method for reducing the pulsation level in a multi-compressor plant where each compressor of a plurality of compressors is driven by a respective motor. The method manages to reduce the pulsation level by starting a first motor of a first compressor and then starting in succession each one of the other motors in a way to synchronize all motors between each other with a specified phase shift.

A liquid supply system providing a stable pump operation even when ultra-low temperature liquid including slurry is set as a liquid feed target. The liquid supply system that supplies ultra-low temperature liquid including a slurry component by expansion and contraction of bellows 41 and 42. At least a region in the bellows 41 and 42 that is in contact with the liquid is coated with resin having a low temperature brittle temperature that is equal to or lower than an operating temperature of the liquid supply system.

A diaphragm pump system that includes a pair of working fluid diaphragm pump assemblies that are each fluidly connected to a working fluid flow. Each working fluid diaphragm pump assembly is operationally associated with a discrete drive arrangement that is fluidly isolated from the working fluid flow that is moved during operation of the pump system. A control arrangement is connected to the discrete drive arrangements and configured to control the cyclic operation of the pair of working fluid diaphragm pump assemblies to mitigate pulsatile effects in the combined working fluid flow when the discharges of the working fluid flows associated with operation of the pair of working fluid diaphragm pump assemblies is combined.

A reciprocating fluid pump includes a pump body, a first subject fluid chamber, a second subject fluid chamber, a first plunger at least partially defining a first drive fluid chamber and including a flexible material and configured to expand and compress in a reciprocating action to pump the subject fluid through the first subject fluid chamber within the pump body, and a second plunger located within the pump body and at least partially defining a second drive fluid chamber and including a flexible material and configured to expand and compress in a reciprocating action to pump the subject fluid through the second subject fluid chamber within the pump body, wherein the first plunger is not structurally coupled to the second plunger, such that the first plunger and the second plunger are independently movable during operation.

A four-cylinder diaphragm pump includes a pump body having four pump chambers, and a drive mechanism that expands and contracts the four pump chambers with a predetermined phase difference, in which the pump body includes a first diaphragm having two diaphragm portions on a same plane, and a second diaphragm having two diaphragm portions on a same plane disposed to be located to be parallel to or coplanar with the plane of the first diaphragm, each of the diaphragm portions of the first diaphragm and the second diaphragm constitute a portion of a different pump chamber, and the drive mechanism is configured to move the diaphragm portions of the first diaphragm and the second diaphragm forward or backward with respect to the corresponding pump chambers with a predetermined phase difference.

A system and method for pumping fluid. The system includes a sequence of two or more positive-displacement sub-systems each having a respective one-way inlet. A respective one-way flow path links each adjacent two of the sub-systems. A one-way outlet from a last of the sub-systems is provided. The system is capable of a mode of operation in which at least some of the sub-systems are substantially in phase with respect to each other to cause the system to draw fluid from more than one of the one-way inlets; and another other mode of operation in which at least some of the sub-systems are substantially in antiphase with respect to each other to increment a pressure of the fluid as the fluid moves along the sequence.

A pump arrangement (1) is provided comprising a driving shaft (2), cylinder drum means (3a, 3b) fixed to said shaft (2) in rotational direction and having a plurality of cylinders (6a, 6b), and a piston (7a, 7b) in each cylinder, each piston (7a, 7b) having a slide shoe (8a, 8b) in contact with driving surface means (8a, 8b). Such a pump arrangement should produce a pressure with low undulations. To this end said cylinder drum means (3a. 3b) comprise at least a first cylinder drum (3a) and a second cylinder drum (3b), said cylinder drums (3a, 3b) being fixed to said common shaft (2) in rotational direction, wherein the cylinder drums (3a, 3b) are offset with respect to each other in rotational direction.