#DRAWDOWN TEST PROCEDURE PDF#
#DRAWDOWN TEST PROCEDURE FULL#

One uses a flow meter for flow measurement and allows plotting of multiple test points. In order to encourage frequent testing, I developed two, simple submersible pump field test spreadsheets for our customers.

In addition to radial loading, operation to the left of BEP can give rise to damaging, suction and discharge recirculation cavitation. This leads to increased shaft deflection which will reduce seal, wear ring and bearing life. The large width, required for solids passage, increases the radial forces on higher head pumps. Wastewater pumps can be problematic when operated at off BEP conditions due to the size of their impellers. Submersible wastewater pumps can be even more of a problem since they are out of sight and often out of mind. These changes can have a major effect on the pump’s operating point on its H/Q curve. These include malfunctioning gate and check valves, partial blockages in the pipeline, air accumulation at a high point and new branches entering a force main, just to name a few.Ĭlear water systems can face similar challenges but the content of the pumpage makes wastewater systems more vulnerable. E ven if a pump operates at BEP at start up, many conditions will change during the coming months and years. Determination of Dyne level by wetting is then performed to a standardised test procedure.All pumps should be tested regularly, but wastewater pumps are at the top of my list as they are especially susceptible to changing system conditions.

As soon as possible, the applicator is then drawn down over this bead, spreading it over the surface. To perform the Dyne test with a “DyneX” applicator, first apply a short bead of surface tension test fluid from a dropper bottle directly to the sample surface. Packed in a cushioned protective container. All four gates are precision ground to the same clearance to facilitate quicker test-to-test turnaround, and to provide the longest service life. For best results, we strongly suggest use on a “DyneX” drawdown platform. This restricted passage channels the flow of the Dyne fluid through the gate whilst limiting the wet film thickness applied to a maximum of only 12.5 microns. This tool can produce high quality drawdowns in a confined area, making direct benchtop testing a reality. A precision ground gate, 38mm wide, is centered on each of the four edges. The “DyneX” applicator measures only 13 x 13 x 64mm. Remarkably fast and easy clean-up saves time and cleaning supplies. With a Teflon® coated surface it is ideal for Dyne testing – no attraction to, or contamination from the applicator affects test results.

#DRAWDOWN TEST PROCEDURE PDF#

See the Metering Rod Selection Chart PDF below for further information. With the use of such non-abrasive cleaners, metering rods can be reused repeatedly. Economical and easy to use simple clean-up with water, alcohol, appropriate solvent and low lint cloths.

#DRAWDOWN TEST PROCEDURE FULL#

These lab rods or drawdown bars can be used either to test two coatings simultaneously, or for full width substrate evaluations using one test liquid.

Rods are available in 6.3mm and 12.7mm diameters. The 400mm long “Mayer” rod has 305mm of wire wound on centre. The rods, widely known as Metering Rods, Mayer Rods or drawdown bars are fabricated from 303 stainless steel the wire winding is 304 stainless steel. Liquid crystal thermometer is accurate to better than 1☌.Īpplies a highly uniform wet film coating.These wire-wound metering rods, when used on a precision surface such as the “DyneX” Drawdown Platform, will apply a highly uniform wet film thickness, which is ideal for Dyne testing. Five pre-adjusted shock absorbing levelling feet and surface mounted spirit level ensure precise levelling and firm footing. Each unit is meticulously inspected to assure flatness. The 305mm x 305mm smoothing pad with closely controlled compressibility is engineered to promote uniform fluid distribution with minimal squirm. 12.7mm thick float glass platform large enough for direct A to B comparisons or evaluation of machine caused treatment variations. Full width magnetic clamp allows precise sample positioning with secure grip.

Drawdown test procedure