To provide a reciprocating pump volumetric efficiency or flow rate of the pump can be monitored easily and accurately . And A pump chamber , a suction port capable of inhaling liquid chamber the pump , a discharge port capable of discharging the liquid in the pump chamber , a plunger 7 it is possible to reciprocate the pump chamber by a motor M is disposed between the flow path of the pump chamber and the inlet side and the discharge port side of the flow channel , and is opened and closed in response to fluid pressure changes in the pump chamber that occurs with the reciprocation of the plunger 7 chuck in reciprocating pump comprising a valve , a detector capable of detecting the time the check valve is in the open state or the closed state in a given period , check valve opens at the detection time and the predetermined period is detected by the detection means based on the comparison between the time of normal which is the state or closed state , and is obtained by including a calculating means for calculating the volumetric efficiency or flow rate of the pump . [ Selection Figure Figure 1【課題】ポンプの容積効率又は流量を容易且つ精度よく監視することができる往復動ポンプを提供する。【解決手段】ポンプ室と、該ポンプ室内に液体を吸入させ得る吸込み口と、ポンプ室内の液体を吐出させ得る吐出口と、モータMによってポンプ室に対して往復動可能とされたプランジャ7と、ポンプ室と吸込み口側の流路及び吐出口側の流路との間に配設され、プランジャ7の往復動に伴って生じるポンプ室内の液圧の変化に応じて開閉可能とされるチャッキ弁とを具備した往復動ポンプにおいて、所定周期においてチャッキ弁が開状態又は閉状態とされた時間を検出し得る検出手段と、該検出手段で検出された検出時間と所定周期においてチャッキ弁が開状態又は閉状態とされる正常時の時間との比較に基づき、ポンプの容積効率又は流量を演算する演算手段とを具備したものである。【選択図】図1
