Positive displacement pumps – chemical applications
The industrial processes involved in chemical manufacture are complex and intricate. With all the transferring operations involved, it's imperative to source the most versatile, reliable and efficient pumping technology. The centrifugal pump has justifiably reigned supreme for many years but positive displacement (PD) pumps, particularly the eccentric disc and sliding vane variants, more than hold their own in direct comparisons.
PD pumps can move higher viscosity fluids with ease, from medium to very viscous fluids (eccentric disc and sliding vane) and liquefied gases to water-like fluids (sliding vane). The technology has proven comparably effective in the chemical plant environment, with similar set up costs as centrifugal pumps that can often result in lower total costs over the lifespan of the pump.
Crucially, positive displacement pumps are designed in such a way that constant flow at a given speed can be achieved regardless of an application's discharge pressure – ideal for the precise dosing rates of many chemical manufacture processes.
Different types of Positive displacement pumps
PD Pump Solutions from Blackmer and Mouvex
SNP Series Sliding Vane Pump
Blackmer SNP pumps are typically used in handling corrosive or caustic fluids like acids, brines and liquid foods. They are built from 316 stainless steel construction, with metallized carbon sleeve bearings and non-metallic vanes, for longer life. The unique non-galling design helps to reduce maintenance costs and operational issues, while the innovative sliding-vane pump design self-adjusts for wear to maintain flow rates.
The SNP Series also feature an adjustable relief valve to protect against excessive pressures; symmetrical bearing support for even loading and wear; a shaft stuffing box that accommodates most standard aftermarket mechanical seal configurations; and excellent self-priming and dry run capabilities. Vanes can be easily replaced, without removing the pump from the piping system, and the clever pump design and operation minimizes shear and agitation.
Mouvex's A-Series pumps utilize an eccentric disc, which enables self-priming (even when dry) and pipe clearing. The automatic clearance make-up system ensures that A-Series pumps maintain their initial performance level over time without any adjustment.
Even considerable changes to the viscosity of the fluid changes result in a regular and constant output, independent of the delivery pressure, thanks to four chambers – moving in pairs 180° apart – that increase and decrease in volume inside the pump body and therefore produce the suction and discharge.
The unique design of the A-Series pump allows it to be continually run in reverse to enable pumping back of products. The unique eccentric disc principle ensures a smooth transfer (low rotary speeds), as well as excellent efficiency, and can handle a huge array of applications.
The SLC Series
The SLC Series of Mouvex's Eccentric Disc Pumps, feature a unique seal-less design with a double stainless steel bellows that ensures durability, safety and product containment. It provides extremely high suction and discharge pressures, allowing it to self-prime and fully strip lines to maximize product recovery.
The SLC can run dry for up to five minutes and the self-compensating eccentric disc principle not only gives consistent flow rates over a long period of time but also a highly accurate flow rate even at low speeds. With fewer moving parts, and therefore decreased maintenance and downtime concerns, the SLC series is suitable for most chemical and industrial transfer applications – even those requiring consistent non-pulsing flow and gentle fluid handling (low shear rates).
So, for optimal fluid transfer in chemical manufacturing, the fluid handling prowess of PD pumps should not be underestimated. Their exceptional design, operation, and versatility credentials mean that they're as kind to your transfer flows as they are to your cash flow.
I have over 30 years experiencing managing and owning Process Industry companies. As a trained engineer with a Masters’ degree in C&I, I have significant technical product and application knowledge
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