Design Codes for Centrifugal Pumps

Gorman Rupp's website seems to be designed to discourage incoming telephone calls. It wouldn't be surprising if potential custom were going elsewhere.

Why is a stress analysis needed on the pumps? Surely it is all taken care of in the piping schedules and good piping practice?

actually just need the nozzle end load data , so see if its well in the right range with the info i got for the piping connection. where could i get this info though

Well, it's a combination of the pressure in the pipe and the weight of pipe suspended from the nozzle.

And this is needed because......?

So you are actually designing piping to a pump and want to confirm that loads applied to the pump are acceptable, correct? If you are unable to get the specific information from the manufacturer there are 2 standards, API610 and ANSI/HI 9.6.2. NEMA SM23 'Steam Turbines for Mechanical Drive Service' contains nozzles allowable loads which are often used for equipment other than turbines.

Actually, I should have thought about this before.

Do you have any kind of documentation on this pump from the vendor? Spec sheet, pump curve, detailed drawing (probably the best place). It should tell you what standard the manufacturer designed their pump to (if any). Check that code for nozzle loads.

I'd follow Holz's advice too. He may have more experience in this than me. But I would think that the codes should be a good guideline for nozzle loading.

A quick google search can pull up something like this (don't waste time on the Gormann Rupp website, it's useless). This type of pump isn't designed or built to any codes or standards.

Allowable nozzle loadings are usually only required when designing pipework systems. You can only get this data from the pump manufacturer.

Table 5 in API 610 covers nozzle loading for its pumps. Did you mean for this particular type of pump?

Table 5 in API 610 gives the recommended minimum for 'Maximum Allowable Nozzle Loadings' for any pump that is to comply with API 610. Pump manufacturers have to comply with this as a minimum figure, and account for it in their pump design if they want to call theirs an API 610 pump. However, that does not mean that these are the actual figures for any given pump by any given manufacturer. Only the pump manufacturer can give you the actual figures for 'Maximum Allowable Nozzle Loadings', and their figures could well be higher (but not lower) than those shown in API 610.

In this instance the OPs pump is not designed to any standard, so he cannot use any of the tables in any standards. He can only get this data from the pump manufacturer.

Well then I say you go with my standard engineering calculations assumption:

These results assume that my calculations are correct.

It works every time I use it...

Go here: PDF] 06B3-B - Hydro Innovations The pump curve is in this document.

What else could you possibly need?

When you say "nozzel end loads" do you mean stress on the nozzel from the pumps pressure?

The design of your piping should not be putting stress on the pump, compressor or turbine at cold conditions. Expansion loops or joints should be added to account for the stress added as the temperatures increase. You are referencing a Cast Iron pump by Gorman-Rupp. Cast iron casings and their flanges are the last thing you should be putting stress on. Design your piping like it's going to mate up with an egg shell and you will have no problems with pump flanges or casings cracking or breaking.

Wouldn't you have to put a support at the piping flange connecting to the pump nozzle to eliminate all of the pipe load on the pump? If you do this, where does the pump foundation go? Do you have adequate access to the pump to remove it for maintenance?

In my experience, it is nice to design for no nozzle loads but I have yet to see an instance where it was practical.

And to the OP, please to your research before suggesting an expansion joint for construction.

You might want to review the following:

http://www.pipingguide.net/2010/08/piping-layout.html

What am I supposed to review? The line that says:

"The suction and discharge piping must be supported independently of the pump such that very little load is transmitted to the pump casing. The designer may consider the use of expansion joints on either the suction or discharge, or both, as necessary. However, expansion joints should be used only when it is unavoidable"

Maybe I didn't write my first comment properly. You CANNOT prevent stresses on the pump nozzle at cold conditions. That's why there's a need to check the stresses against code or manufacturer recommendations.

For instance, you have pipe in a pipe rack that drops down to the horizontal suction of a pump. You'll need a 90 and probably about 3 feet of pipe to get to the suction (maybe more depending on what kind of flow condtions you want at the suction). Most likely, you'll add a support at the elbow to reduce stresses in the pipe and at the pump. Which means that half of the weight of the 3 ft of pipe is supported by the pump nozzle.

If that pipe is 8" XH carbon steel pipe then it will create a bending moment of about 100 ft-lb. Not much but it needs to be considered. Especially if you have pipe operating at 400F (where thermal stresses and expansions have a significant effect).

I could be wrong but I get the impression that if the OP is asking for a code to give him nozzle loads it's because he has done a stress analysis, asked the vendor for info, and still has nothing to compare his results to.

Probably a hundred thousand or more ways to eliminate piping loads on equipment (pumps, compressors, turbines, heat exchangers, distillation towers, fractionating columns etc .) in this catalog: http://www.pipesupports.com/node/552#attachments

An excerpt from the thread

"A pipe anchor must be provided between any expansion joint or non rigid coupling and the pump nozzle that it is designed to protect.

When routing piping at pumps, the designer should follow the manufacturer's recommendations, the Hydraulic Institute Standards, and the following guidelines:

● The suction and discharge piping must be supported independently of the pump such that very little load is transmitted to the pump casing. The designer may consider the use of expansion joints on either the suction or discharge, or both, as necessary. However, expansion joints should be used only when it is unavoidable. (This is a reference to the use of bellows or slip joint expansion joints as opposed to expansion loops in the piping that I was referring to in my previous post.

● When pump flanges are cast-iron flat-faced, the mating flanges must also be flat faced and the joint made up with full-face gaskets and common steel bolts (ASTM A 307, Grade B), not high-strength bolts (ASTM A193, Grade B7)."

Your second link looks like a good post. I'll have to read it next week when I get back (half day today).

Expansion joints have had a recent history of failing due to overuse and underanalysis. It's not as simple as "it meets the design pressure."

Totally agree. Am not a fan of "expansion joints" .