Over the last several weeks we discussed the feared NPSH and showed it is rarely an issue at design conditions. More often than not, noise and pressure problems are caused by air in the suction piping system. The suction pipe, in many cooling pumping systems, is under very little pressure. In fact, the suction of the pump could be under a vacuum.
It’s all about Pressure – Cooling Tower Pumps and Piping – Part 5
Last week the R. L. Deppmann Monday Morning Minute gave an example of a pump selection for which we applied the margin multipliers to arrive at 24.5 feet of net positive suction head required or NPSHR. Now let’s turn our attention to the cooling tower pump suction piping and net positive suction head available or NPSHA. [Read more…]
It’s all about Pressure – Cooling Tower Pumps and Piping
Last week the R. L. Deppmann Monday Morning Minute left you with a multiplier of 1.3, 1.5, or 2.0 to use with the pump NPSHR. Let’s look at an example this week using the suction energy formula we introduced last week and add one more margin to the formula.
Where Cavitation Begins – Cooling Tower Pumps and Piping
Last week the R. L. Deppmann Monday Morning Minute defined NPSHR, and ended with the Hydraulic Institute (HI) definition as the absolute pressure that will cause the total head of the pump to be reduced by 3%, due to flow blockage from cavitation”. Of importance is the fact that it does not say that NPSHR is where cavitation begins.
It’s All About Terms! – Cooling Tower Pumps and Piping – Part 1
Most cooling tower designs and installations are commissioned without any issues. The few percent of times where problems arise will cause multiple meetings, emails, finger pointing, and added costs. The issues are not caused by bad luck or bad Karma; tower water pumping issues are typically caused by air, dirt, or improper application. [Read more…]
B & G ecocirc e3 with ECM Technology (Electronically Commutated Motor)
Bell and Gossett’s ecocirc pumps were introduced over the last few weeks. We promised to explain how the ECM technology provides more efficiency than standard induction motors. Let’s talk about the difference between a standard induction motor vs. a permanent magnet motor. With an induction motor, stator windings are arranged around the rotor so that when they’re energized, they create a rotating magnetic field.
Let us take some time to answer YOUR questions…
We received a great deal of questions from last week’s Monday Morning Minutes on the Bell and Gossett Ecocirc domestic water inline pump. Two of the most asked questions were; Why is more reliable? And How does it save energy? The ECOCIRC is more reliable because there are less moving parts. Here is a brief description.
NEW PRODUCT: Energy Efficient Ecocirc 19-14 Auto & Vario Heat Circulators
We are very pleased to announce the addition of the new ecocirc 19-14 heating circulators to our line of energy efficient products. As with the rest of the ecocirc line, this new offering also utilizes Electronically Commutated/Permanent Magnet motors, which by design are more efficient than permanent split capacitor induction motors. This technology also offers more flexibility than standard motors allowing us to add features via software logic rather than hardware that would otherwise add cost.
Centrifugal Pump Readout Corrections – Part 2
Last week the Monday Morning Minute introduced some considerations when using gauge readings to compare with your centrifugal pump curves. Today let’s look at some additional corrections. The vertical axis on the pump curve is the total dynamic head (TDH). When taking gauge readings at the pump tappings provided, we must consider three possible contributors to the
Centrifugal Pump Readout Corrections – Part 1
Last week the Monday Morning Minute article outlined the procedures we use during a check, test, and start-up of a B&G centrifugal pump. After converting from field gauge readings in PSIG to pump head in feet, there are several reasons why the results may be incorrect. The speed of the motor is different than the speed of