## Pump Suction Piping Rules – Cooling Tower Pumps and Piping – Part 7

Norm Hall

This week we continue our suggestions for tower pump suction piping. In order to minimize problems with air, noise, and NPSH at the tower pump, Bell and Gossett recommends you try to keep high pressure drop devices out of the suction piping and also keep the velocity low. Let’s examine high pressure drop device this week.

## Pump Suction Piping Rules – Cooling Tower Pumps and Piping – Part 6

Norm Hall

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

Norm Hall

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

Norm Hall

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

Norm Hall

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

Norm Hall

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…]