A screw pump is a positive displacement pump that use one or several screws to move fluids or solids along the screw(s) axis. In its simplest form (the Archimedes' screw pump), a single screw rotates in a cylindrical cavity, thereby moving the material along the screw's spindle. This ancient construction is still used in many low-tech applications, such as irrigation systems and in agriculturural machinery for transporting grain and other solids.
Development of the screw pump has led to a variety of multi-axis technologies where carefully crafted screws rotate in opposite directions or remains stationary within a cavity. The cavity can be profiled, thereby creating cavities where the pumped material is "trapped".
In offshore and marine installations, a three spindle screw pump is often used to pump high pressure viscous fluids. Three screws drive the pumped liquid forth in a closed chamber. As the screws rotate in opposite directions, the pumped liquid moves aling the screws spindles.
Three-Spindle screw pumps are used for transport of viscous fluids with lubricating properties. They are suited for a variety of applications such as fuel-injection, oil burners, boosting, hydraulics, fuel, lubrication, circulating, feed and so on.
Compared to centrifugal pumps, positive displacements (PD) pumps have several advantages. The pumped fluid is moving axially without turbulence which eliminates foaming that would otherwise occur in viscous fluids. They are also able to pump fluids of higher viscosity without losing flow rate. Also, changes in the pressure difference have little impact on PD pumps compared to centrifugal pumps.
Working Of Screw Pump:-
Screw pumps also falls in the category of rotary pumps and have the same mechanism and principle. Screw pumps are the only type of pumps which are different from other rotary displacement pumps because of the axial flow of the fluid through their pumping elements.The fluid in screw pumps moves between the screw threads and is displaced axially as the screws rotate and mesh.
Due to the axial flow pattern and low internal velocities,the screw pumps have certain advantages in applications where churning and agitation of fluid is highly objectionable or not allowed.The inter-meshing of the screw threads on the rotors and the very fine clearances of the surrounding housing creates a seal between the pumps inlet and outlet.
Due to the rotation of the screws and the movement of fine clearances, pockets are formed in the helices of the screw.As the screw moves the pockets also move axially and act similar to a piston moving in one direction, while the fluid is moved axially from inlet to outlet.
Development of the screw pump has led to a variety of multi-axis technologies where carefully crafted screws rotate in opposite directions or remains stationary within a cavity. The cavity can be profiled, thereby creating cavities where the pumped material is "trapped".
In offshore and marine installations, a three spindle screw pump is often used to pump high pressure viscous fluids. Three screws drive the pumped liquid forth in a closed chamber. As the screws rotate in opposite directions, the pumped liquid moves aling the screws spindles.
Three-Spindle screw pumps are used for transport of viscous fluids with lubricating properties. They are suited for a variety of applications such as fuel-injection, oil burners, boosting, hydraulics, fuel, lubrication, circulating, feed and so on.
Compared to centrifugal pumps, positive displacements (PD) pumps have several advantages. The pumped fluid is moving axially without turbulence which eliminates foaming that would otherwise occur in viscous fluids. They are also able to pump fluids of higher viscosity without losing flow rate. Also, changes in the pressure difference have little impact on PD pumps compared to centrifugal pumps.
Working Of Screw Pump:-
Screw pumps also falls in the category of rotary pumps and have the same mechanism and principle. Screw pumps are the only type of pumps which are different from other rotary displacement pumps because of the axial flow of the fluid through their pumping elements.The fluid in screw pumps moves between the screw threads and is displaced axially as the screws rotate and mesh.
Due to the axial flow pattern and low internal velocities,the screw pumps have certain advantages in applications where churning and agitation of fluid is highly objectionable or not allowed.The inter-meshing of the screw threads on the rotors and the very fine clearances of the surrounding housing creates a seal between the pumps inlet and outlet.
Due to the rotation of the screws and the movement of fine clearances, pockets are formed in the helices of the screw.As the screw moves the pockets also move axially and act similar to a piston moving in one direction, while the fluid is moved axially from inlet to outlet.
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