Abstract: When a pipe pressure of a common discharge pipe during an independent discharge step in which only one reciprocating pump among a plurality of reciprocating pumps discharges a fluid to the common discharge pipe differs from internal pressures in pump chambers of the respective reciprocating pumps at discharge step start point angles, a stroke adjustment mechanism adjusts, on the basis of a pressure difference ?P therebetween, effective stroke lengths of cross heads connected to plungers of the predetermined reciprocating pumps so that the internal pressures in the pump chambers reach the pipe pressure at the discharge step start point angles.

Abstract: When a pipe pressure of a common discharge pipe during an independent discharge step in which only one reciprocating pump among a plurality of reciprocating pumps discharges a fluid to the common discharge pipe differs from internal pressures in pump chambers of the respective reciprocating pumps at discharge step start point angles, a stroke adjustment mechanism adjusts, on the basis of a pressure difference ?P therebetween, effective stroke lengths of cross heads connected to plungers of the predetermined reciprocating pumps so that the internal pressures in the pump chambers reach the pipe pressure at the discharge step start point angles.

Abstract: A non-pulsation pump is provided with: a cam mechanism that converts the rotational motion of a shared motor into reciprocal motion having a prescribed phase difference; a plurality of cross heads that make reciprocal motion with a prescribed phase difference through the cam mechanism; and a plurality of reciprocating pumps that are driven with a prescribed phase difference and that include plungers connected to the cross heads, wherein the total discharge flowrate toward a shared discharge pipe is kept constant. This non-pulsation pump includes a preliminary compression step for moving the plungers of the reciprocating pumps to a discharge side by very small amounts before a discharging step but after a suction step, and has a stroke adjustment mechanism for adjusting the effective stroke length of the plunger in the preliminary compression step. Thus, generation of pulsation can be suppressed even when the set pressure changes.

Abstract: A non-pulsation pump is provided with: a cam mechanism that converts the rotational motion of a shared motor into reciprocal motion having a prescribed phase difference; a plurality of cross heads that make reciprocal motion with a prescribed phase difference through the cam mechanism; and a plurality of reciprocating pumps that are driven with a prescribed phase difference and that include plungers connected to the cross heads, wherein the total discharge flowrate toward a shared discharge pipe is kept constant. This non-pulsation pump includes a preliminary compression step for moving the plungers of the reciprocating pumps to a discharge side by very small amounts before a discharging step but after a suction step, and has a stroke adjustment mechanism for adjusting the effective stroke length of the plunger in the preliminary compression step. Thus, generation of pulsation can be suppressed even when the set pressure changes.

Abstract: A diaphragm pump prevents deformation, breakage, and the like of a diaphragm caused by the diaphragm being pushed strongly against a discharge opening during operation of the diaphragm pump, and that also provides smooth fluid transfer of the pumped fluid. At its extreme discharge position, the diaphragm is blocked from entering the pumped fluid discharge opening by a perforated diaphragm protecting device covering the fluid discharge opening. Selection of the size of openings in the diaphragm protecting device, appropriate for the materials being pumped, allows smooth movement of pumped fluid in the pump through the pumped fluid discharge opening, without interference. In one embodiment, the diaphragm protecting device is a movable perforated plate which is resiliently urged open, and which is pushed closed when the diaphragm reaches its discharge extreme position.