Delta PD Pumps Pvt. Ltd.

Wadala, Mumbai, Maharashtra

The pumping elements are rotor and stator. The single helical rotor rolls eccentrically in a double threaded helix stator of twice the pitch length. A series of sealed cavities 180 apart are created that appear to progress from suction to discharge during one rotation of rotor. The opposing cavities fill and empty simultaneously resulting in a pulsation less flow. The fluid travels axially with relatively low velocity and minimal agitation. The stator is made of a resilient elastomeric material and bonded to the stator tube. The important feature of the pumping principle is the ability to handle slurries and solid particles. The elastomeric stator also permits passage of solid particles due to elastomeric deformation.

Only two rotating parts having principle of gear within gear but without crescent. The inner rotor is located off-center and both rotors rotate. The geometry of the two rotors partitions the volume between them into N different dynamically-changing volumes. During the assembly's rotation cycle, each of these volumes changes continuously, so any given volume first increases, and then decreases. An increase creates a vacuum. This vacuum creates suction, and hence, this part of the cycle is where the intake is located. As a volume decreases compression occurs. The Flow of liquid is axial through the elements. In built features of speed reduction as pinion is rotated at prime mover speed and outer gear rotates at lower speed.

TYPICAL APPLICATIONS

Transfer and Barrel unloading

Pressure lubricating & cooling of bearings & gear boxes.

Pumping, heating, cooling and filtering units.

Pre-lubrication of components of machinery before starting.

COST COMPARISON

Very economical and costs fraction of screw pumps

Power consumption is less than conventional pumps. Hence economical in operation.

A pair of specially profiled screw, machined integral from solid stock and well supported on antifriction bearings run in precision bored interchangeable casing liners. Each screw set has one right hand and one left hand screw engaging with a similar but opposite hand screw pair. A pair of hardened and profile ground timing gears synchronize the screws to maintain a small but positive clearance between the flanks thus ensuring no metal to metal contact. The pumps can therefore run dry for sometime without any damage. This unique feature enables to run the pump even dry and handle fluids that do not have enough lubricating value and also very low or high viscous products. Consequently, since there is no metal to metal contact; wear and tear is reduced to the minimum, ensuring extremely long service life. With two pairs of screws running in the same casing, the internal velocities are very small - consequently the NPSHR is practically the lowest even when the pumps run at motor speeds and while handling viscous products. Opposed screw pitches totally eliminate axial thrusts. Relatively small diameters of screws enables the pump to operate at high speeds directly coupled to prime movers - without the need for speed reducers even while handling high sealings always under suction pressure, thus making use of simple, inexpensive seals. The axial flow without turbulence, rotation, churning, chewing guarantees gentle handling of products. Noise and vibration or ---- levels are about the lowest. Positive clearance between running parts makes it easier to construct the pump in different materials safely, especially in stainless steel, without the fear of seizing. Thus a variety of fluids can easily be handled by selecting the right materials of construction.