Pumping high viscosity liquids9/9/2023 ![]() Suction and discharge lines must be increased by at least one, or better, two pipe sizes over the size of the pump ports.When pumping viscosities above 100 cp, call our Application Specialists to determine optimal rpm and other operating parameters. Pump speed (rpm) must be reduced if viscosity is above 100 cp.Gear pumps are well suited for pumping viscous liquids if the following rules are observed: Viscosity typically decreases with temperature and if the fluid will not be compromised by heating this will make it easier to pump. Heat your fluid, if possible, at the source or in an immersion bath. BioPharm, BioPharm Plus, Tygon® E-Lab, Tygon® E-LFL, Puri-Flex® or silicone formulations are good choices. A smooth bore will minimize frictional forces. The quicker return allows liquid to be pulled into the tubing with greater force. For L/S®, and I/P® sizes, choose high-performance precision tubing-the thicker wall tube sizes also return more quickly to their original shape than precision tubing. Performance will be better because the firmer tubing returns to its original shape quickly after pump head occlusion creating the suction needed to pump the viscous fluid. Choose a firm tubing such as Chem-Durance® Bio, Norprene®, PharmaPure®, PharMed® BPT, Tygon® E-LFL, GORE® STA-PURE® Series PCS or GORE® STA-PURE® Series PFL.Choose a larger size tubing than required to pump water.The maximum efficient speed of the pump decreases as viscosity increases and tubing size decreases. Increasing the speed beyond a certain point will have a diminishing effect on flow rate. To maximize the pumping efficiency of viscous fluids, follow these steps: The design of peristaltic pumps makes them suitable for abrasive and/or viscous fluids such as suspensions, creams, slurries, lubricants, paints, liquid waste, and more. Pumping viscous liquids with: Peristaltic pumps Viscosities for typical liquids Typical liquid Some examples of thixotropic liquids are soaps, tars, vegetable oils, shortening, glue, inks, peanut butter, and some slurries. Often the viscosity will not return to its initial value. When agitation is stopped or reduced, hysteresis occurs and viscosity will increase. Thixotropic liquids-Like a pseudoplastic liquid, viscosity decreases as shear rate or agitation increases. Some liquids showing dilatant behavior are slurries, clay, and candy compounds. Pumps can bog down and stall after initially pumping dilatant liquids. Typical pseudoplastic liquids are gels, latex paints, and lotions.ĭilatant liquids-Viscosity increases as shear rate increases. Pseudoplastic liquids-Viscosity decreases as shear rate increases, but initial viscosity may be great enough to prevent flow from starting in a typical pumping system. Liquids displaying Newtonian behavior include water, mineral oils, syrup, hydrocarbons, and resins. As pump speed increases, flow increases proportionately. Newtonian liquids-Viscosity remains constant regardless of changes in shear rate or agitation. The effects of viscosity can be better understood by looking at the behavior of viscous liquids when subjected to force. ![]() When selecting a pump, fluid viscosity must always be considered. Pumping viscous liquids can present some difficult problems. HALO® Chromatography Columns and Consumables+. Sartorius laboratory instruments, consumables and services PerkinElmer - Innovating for a Healthier World Lab Thermometers & Temperature Measurement EquipmentĪgilent Chemistries and Supplies Portfolio Quality Products from Sheldon Manufacturing ![]() Life Science Research Solutions, Products, and Resources VWR will support you from the latest life science products to the guaranteed purity of organic building blocks. A strong, vibrant research and development group is the lifeblood of all industries.
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