Blackmer Pumps has addressed these issues, with the result being the Mouvex principle. This is based on the operation of an oscillating eccentric piston that produces the pumping performance of a rotary positive displacement pump. However, its action is far more sensitive making it ideally suited to applications where shear and potential leakage are major issues.
The Mouvex principle pump differs from other types of positive displacement pumps in that it does not agitate the pumped liquid. Rather, the liquid is pumped by the eccentric movement of the oscillating piston within the pump chamber, this being a very gentle action. The direct-drive design of the pump does not require either mechanical seals or magnets, so it provides leak-free performance.
The eccentric movement pump consists of a cylinder and a pumping element mounted on an eccentric shaft. As the eccentric shaft rotates, the pumping element creates chambers with the cylinder. This has the effect of increasing the size of the intake port and drawing fluid into the pumping chamber. The fluid is transported to the discharge port where the size of the pumping chamber decreases. The action squeezes the fluid out into the discharge pipework.
Suitable for throughputs up to 36m3/h and pressures up to 9 bar, Blackmer Mouvex C and S Series pumps provide a constant product flow that is independent of both pressure and viscosity. This, together with the presence of automatic piston/cylinder wear adjustment, ensures full flow efficiency and high levels of product stability at all times. In addition, the design ensures that very high levels of accuracy can be attained for volume metering and dosing.
The Blackmer Mouvex C and S series pumps, whilst employing the same operating principle have sharply contrasting designs. In the case of the C Series, the eccentric shaft is encased within metal bellows constructed from 316 stainless steel. Available in both 316 stainless steel and ductile iron construction, the ATEX compliant C-Series conforms to standard 3A and the hygienic recommendations required by EHEDG.
Self-priming and capable of dry-running, this type of pump will clear both the intake and discharge lines of any residual liquid. Lubrication of all moving parts is provided by the pumped medium. Cleaning is performed in place simply by flushing out the unit without any requirement for disassembly. Applications within the cosmetics and personal care products sectors are perfectly suited to this type of pump.
The high priming capacity of the pump ensures good decanting regularity and enables the pump to run in a dry condition for several minutes which is of importance at the end of decanting. The excellent volumetric accuracy of the pump makes it possible at the moment of decanting to simultaneously supply a filtering battery before supplying a storage tank preceding final preparation. Furthermore, the close tolerance characteristics of the pump design provide good priming capability.
In contrast, the S Series pump is a more compact and lightweight unit, having the transmission mechanism protected by a high-resistance elastomer sleeve that is both odourless and taste-free. This enables the pump to meet the requirements for FDA certification (S4C and S6C). Very much intended for personal products processing duties, S Series Mouvex pumps have been designed for CIP and SIP cleaning. The slow movement of the oscillating piston provides accurate volumetric metering and enables precise dosing and mixing for viscous or fluid products.
Being ATEX, EHEDG and FDA compliant, applications for Blackmer Mouvex pumps are many. In other types of positive displacement pumps the shear sensitive products encountered in manufacturing present considerable problems for mechanical seals, whilst aggressive liquids contribute to premature wear of seals. This is not the case with the Mouvex principle. None of the wetted pumping elements rotate, thereby creating the gentle, low shear forces that many processes require.