Centrifugal Pump Bases

[nucleareng78]

We have a 900 rpm pump and are wanting to re-do the piping so that we have 5 feet of suction piping before it hits the impeller (let the flow settle out).

The problem is, in order to get that 5 feet we need to raise the pump's suction level pretty high (around 2.5-3 feet). We are considering a 1 foot concrete pad with a 2 foot metal platform.

Has anyone had experience mounting a pump to a metal platform? Or had a concrete pad higher than 1 foot? It's not a very large pump but would be have to do some sort of additional calc to verify it would not topple over? It's only 2 feet of metal platform though.

 

[Artisi]

Probably many more postings to come going over the same old ground. For this one we haven't even looked at the natural frequency of the steel structure in depth as yet nor its interaction with any frequency input of the pumpset, blade pass frequency, operation off BEP, although we do have airpockets, possibly 5 ft of unsupported inlet pipework and probably a myriad of other percieved problems. Stay tuned.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[Artisi]

And don't forget the other forum, "inches of oil" probably good for many more posts yet.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[EnergyMix]

nucleareng78

Please be careful about doing anything with those tunnels. They are probably there to supply the safety related water supply to your nuclear plant in the event of an accident. You don't want to mess with them. Here's a link to a real event from a while back where someone forgot this fact:

http://allthingsnuclear.org/fission-stories-104-a-big-dab-will-cost-you-650/.

Unfortunately, the NRC report is in their old document system and so not easily retrievable, but the plant ended up being shutdown for several years as a result of this "small error" by a new engineer.

Is this really a fire pump at a nuclear plant? With putting your pump on a metal platform you might want to consider whether you have to meet seismic requirements -- not so much for the fire pump itself, although it might, depending on what it's used for, but for surrounding equipment. This is often called "Two over one" (or more properly "II over I") indicating that you have lower seismic category equipment that can affect equipment that has higher seismic qualifications. There will be a safety analysis report that will tell you what you are committed to.

 

[nucleareng78]

Why do ArtsyBoy and BigInch bother posting then? If you have a problem with a thread it's pretty easy to NOT post in it.

This is not a fire pump. It's a pump for a condenser cleaning system. No seismic or safety related requirements.

I was simply looking for pump support standards that we could use.

 

[BigInch]

Why? I'm trying to keep it going.

"People will work for you with blood and sweat and tears if they work for what they believe in......" - Simon Sinek

 

[LewisWHilliard]

This may be a stupid question, but, why are you re-piping? What is the actual problem with the system to begin with?

 

[EnergyMix]

Thanks for clearing that up nucleareng78. Presuming that you are at a nuclear plant, then my comment about the tunnel may still apply. Let me just say, it was not a fun time.

The comment about the pump may does not apply; however, you still should verify that there is no safety equipment in the area.

You also want to look into an NRC regulation called "50.59" before you go much further. You don't make changes at a nuclear plant without lots of paperwork, even over on the condenser side.

This is meant to be helpful -- the paperwork side can trip you up, if you're not careful.

 

[ApplicationENG]

The other considerations are the nozzle loads, foundation/baseplate stiffness, and vibration. if the metal platform is not properly designed, the platform itself may not take the piping loads, or may exacerbate the vibration, or provide insufficient stiffness coefficients .

All concrete is the way to go and mount the base on top. Although, i have seen pump baseplates mounted on metal platform for exactly the same reasons you are discussing - although this is not best practice.

 

[nucleareng78]

It is fiberglass piping so the nozzle loads will beI minimal. Thanks for the input