Positive-Displacement Pumps  Manufacturers, Traders, Suppliers

Function and design of positive displacement pumps: To convey a fluid or gas, a positive displacement pump indispensable, which operates in a closed system with flaps and valves. These pumps consist of a housing with piston sleeve, inlet and outlet, inlet and outlet valve as well as a piston (reciprocating pumps). The T-shaped device is operated inside by the piston, which in principle moves up and down. For example, the inlet valve can be located on the left and the outlet valve is located parallel to it. On the side of the upper OT (dead centre) is the housing filled with liquid or gas to be pumped. When the piston finally moves from top to bottom, a vacuum is created and the gas or liquid can be conveyed. Depending on the manufacturer, the models of positive displacement pumps can vary in size, but do not differ in their actual function, regardless of whether new model or used. The vacuum influences the delivery rates: The vacuum exerted inside the positive displacement pump plays a major role in the delivery rate. Since the delivery rate is limited due to the negative pressure, the pumps are also able to operate in a self-priming manner. The positive displacement pump is able to pump the gas or liquid to a certain degree to compress it and thus generate the vacuum. The fluid is then automatically attracted. The characteristic curve as an indicator: The characteristic curves of a positive displacement pump represent the course of the delivery head, the power requirement, the pump efficiency and the required NPSH value above the flow rate. The shape characteristic of the line depends on the design of the impeller, the pump housing or the specific speed. Minor influences such as size, construction tolerance and cavitation, as well as physical properties such as solids transport, viscosity (viscose pumps) or material transport, are not taken into account in this respect. Positive displacement pumps include diaphragm pump gear pump