Pump Suction Piping Rules – Cooling Tower Pumps and Piping – Part 8

Norm HallMonday Morning Minutes, Pumps, Cooling Towers, Hydronic System Design, Cooling Towers, Piping and Pumps, Cooling, Cooling Towers

Traditional hydronic piping system designers use tools such as the Xylem Bell & Gossett System Syzer for pipe sizing. You may find this program at http://completewatersystems.com. Tower manufacturers, the Hydraulic Institute (HI), and Bell and Gossett all suggest lower velocity for pipe selection in cooling tower pump suction piping. Bell and Gossett has several pipe sizing suggestions…

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

Norm HallCooling Towers, Monday Morning Minutes, Pumps, Cooling Towers, Hydronic System Design, Cooling Towers, Piping and Pumps, Cooling

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 HallCooling Towers, Piping and Pumps, Cooling, Cooling Towers, Monday Morning Minutes, Pumps, Cooling Towers, Hydronic System Design

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 HallPumps, Cooling Towers, Hydronic System Design, Cooling Towers, Piping and Pumps, Cooling, Cooling Towers, Monday Morning Minutes

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…]

Where Cavitation Begins – Cooling Tower Pumps and Piping

Norm HallPumps, Cooling Towers, Hydronic System Design, Cooling Towers, Piping and Pumps, Monday Morning Minutes, Cooling, Cooling Towers

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 HallMonday Morning Minutes, Pumps, Cooling Towers, Hydronic System Design, Cooling Towers, Piping and Pumps, Cooling, Cooling Towers

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…]