DOSING PUMP Drawing Figure
Chemical pump,Dosing Pump,High pressure pump,Dosing Equipment > news > Views
till present within the predelivery chamber is delivered back into the container 16 for dosing agent through the return conduit 43. A portion 32' of the predelivered amount of dosing agent remains above the dosing piston 4, because the outlet 45 is in vertical direction on a higher level than the upper inlet of the pump cylinder 2. The difference of level between the outlet 45 and the inlet of the pump cylinder is selected such that a desired portion of the pump cylinder surface always remains within the delivered dosing amount in order to avoid the formation of an incrustation at the dosing piston 4. During the suction of dosing fluid the sump 27 is permanently filled with dosing agent. At the upward movement of the dosing piston 4 the dosing agent is sucked from the sump 27 through the suction conduit 31 and the suction valve 30 into the pump cylinder 2 such that in this chamber an evacuation leading to a crystallization or polymerisation is avoided. The size of the sump is selected such that at the suction there always remains sufficient fluid and air pulsating in the conduit 41 during the operation is prevented from entering into the suction valve 30 of the dosing pump DESCRIPTION The invention refers to a dosing pump comprising a pump cylinder connected at its inlet side with a predelivery chamber and at its outlet side with a dosing point and a dosing piston cooperating therewith as well as a diaphragm, whereby the predelivery chamber is positioned above the pump cylinder and is connectable with a container for dosing agent via a suction conduit comprising a suction valve and a return conduit comprising a pressure valve. In a known dosing pump with dosing piston-cylinder-means and predelivery diaphragm the predelivery chamber is connected with a container for dosing agent via a suction conduit comprising a suction valve and a return conduit comprising a pressure valve. The predelivery is performed via the suction conduit and the suction valve to the predelivery chamber. The dosing piston takes the required amount of dosing agent from the predelivery chamber. The excess amount of dosing agent is transported back into the container for dosing agent via the pressure valve and the return conduit. In a known dosing pump the pump cylinder is connectable with a dosing point via a pressure valve. When the piston is withdrawn from the cylinder a vacuum is drawn which causes volatilization of the dosing agent. In using certain dosing agents such as s