A pump is a device designed to convert mechanical energy into fluid motion energy. According to the principle of pumps’ operation they are divided into two large groups: continuous flow pumps and positive displacement pumps. The first type of the pump oeprates on the principle of inertia. Positive displacement pumps work due to pressure forces. Both types of devices can be used for pumping liquid fuels.
Positive displacement pumps are more sensitive to purity of liquids. Their work is characterized by high vibrations, so it is recommended to install them on a special foundation. The advantages of these devices include the ability of self-feeding. According to the type of mechanical action positive displacement pumps are divided into membrane pumps, piston pumps, plunger pumps, screw-type pumps, gear-wheel pumps and vane-type pumps.
Continuous flow pumps are primarily used where it is necessary to pump large volumes of liquid fuel. They are less demanding to the purity of pumped liquids, but at the same time they don’t have self-feeding capability. Continuous flow pumps are divided into impeller pumps (jet-type and axial-type) and friction pumps (jet-type and vortex-type). The operating principle of impeller pumps is based on energy transfer from the rotating blades to the fluid. Accordingly, the energy in friction pumps is transferred due to the action of friction forces. The pumped fuel in vortex pumps is affected by the impeller movement, which causes the occurrence of eddying flux. Jet-type pumps are operated by applying kinetic energy of fluid, gas or vapor jet stream to the processed fuel.
A piston pump is one of the mechanical variations of manual fuel pumps, so it does not require connection to the mains. Piston pumps are suitable for pumping high-viscosity liquids, their operation is quiet, and their dimensions are very compact.
Self-feeding pumps may be used both on vessels and on construction sites for supplying fuel from deep wells. Almost all positive displacement pumps have a self-feeding capability, but at the same time they feature low efficiency.