Ruhrpumpen Pumps Reliability 1

[GHartmann]

Does anyone have any experience with Ruhrpumpen pumps:

1) Vertical Turbine Pump Type VCT 37KXH - Utilized in below grade cooling tower basin for providing 16,500 GPM of cooling water at 65 psig

2) Horizontal (axial) split case between bearing (non API610) type HSM - Utilized for boiler feedwater duty of 345 GPM / 1635 ft of head (685 psig)

I am trying to get a feel for their reputation/reliability/service in the chemical process or utility industry.

THANKS

 

[micalbrch]

They are a German company with 60 years of experience in manufacturing pumps. I think that is at least not bad. Ask them for a reference list for your specific service.

 

[AdrLad]

I have worked with them in our project. They are a good manufacturer and are the ones to be trusted.However, I agree with micalbrch, you must ask for reference list for your specific service. It will help a lot.

 

[JJPellin]

We have a Byron Jackson model 37 KXH - VCT running in cooling water service at 16,000 gpm and 45 psi discharge. Our pump is driven by a diesel engine through a right angle gearbox. The pump runs at 700 rpm. This product line was sold to Ruhrpumpen several years ago as part of the merger forming Flowserve Pumps. Our pump has had very good reliability, but it rarely runs. Since it is driven by a diesel engine, it only runs when one of the motor driven pumps is out of service.

Johnny Pellin

 

[GHartmann]

JP:

Thanks for the information.

 

[diverdan8]

GHartman,
I am a National Sales Manager for Ruhrpumpen Inc.
I can supply whatever material you may need from our company.
Please feel free to email me aytime at dwaddell@ruhrpumpen.com

 

[JJPellin]

We have had mixed results with newer purchases from Ruhrpumpen. The last set of pumps I purchased involved 4 pumps, 1000 HP,l 20,000+ gpm for another cooling tower project in 2002. They were manufactured and tested at an old Byron Jackson plant in Tulsa. They worked out well and are still running well to this day. Another project involved a between bearings pump with a Stainless Steel case (316 SS). The case failed on start-up with casting defects. It took a long time to work out the warranty implications and get resolution. I prefer Ruhrpumpen for big verticals. Not so much for between-bearings horizontals.

Johnny Pellin

 

[GHartmann]

JP:

What type of MOC did you use for the vertical cooling water pumps?

Our installation will be in a fertilizer facility consisting of ammonia, nitric acid, and ammonium nitrate plants.

We are considering Cast Iron Case with 12% chrome impeller (A487 CA6NM) to avoid rusting / corrosion.

Bronze alloys are not acceptable due to presence of trace NH3 (20 PPM max) in cooling water return

THANKS

 

[JJPellin]

Our pumps were cast iron with a very specific coating that has worked well for us in cooling water service. I am not an expert on the coating. I could state the brand name, but it would really not tell you what you need to know. The impellers were CA6NM. The shafts were carbon steel with 410 SS sleeves at the line-shaft bushings. Most of our other cooling water pumps have 410 SS shafts. Our pumps were purchased with mechanical seals with a ball bearing built into the seal to add additional support. We had submersible accelerometers mounted on the suction bells routed to the surface to check for any indications of cavitation. We had specially designed strainers added to prevent pre-rotation. We took these additional precautions because were installing new, larger pumps in existing sumps and were concerned about unanticipated cavitation because of the sump geometry.

Johnny Pellin

 

[GHartmann]

Thanks for the information. Exactly what I was looking for.

 

[diverdan8]

GHartman,
Please understand that any pump is only as good as the application it is designed for. I understand your concerns, as well as everyone else's. May I say that Ruhrpumpen's "standard" built pumps (37KXH and the HSM among others) have a very good reputation through out the industries. As for the special build pumps , such as JJPellin's experience, we have had very good success with as well, and I am discourage to read a situation such as he experienced.
Since 2008 we have made tremendous changes in our quality control department an continue to do so.

 

[Artisi]

Johnny

"........... We took these additional precautions because were installing new, larger pumps in existing sumps and were concerned about unanticipated cavitation because of the sump geometry."

Do you really mean cavitation in its real sense or anticipated poor entry conditions to the pump inlets - which would be a worry if installing larger pumps in an existing sump.

Ian

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.)

 

[rmw]

Or cavitation as synonymous with vortexing?

rmw

 

[Artisi]

It may not lead to vortexing, although disturbed flow patterns into the pump inlet/s could / should be expected. Of course that will depend entirely on the sump size and geometry together with pump placement etc.
For me, cavitation is cavitation, a result of a conflict in NPSHa/r where as vortexing is a different animal and an unrelated problem, although a condition which is possible even with adequate NPSHa/r margins.

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.)

 

[rmw]

I was addressing the facts presented:

Larger pumps in an existing sump inferred less than optimal sump design. Cooling water reference using verticals inferred temperatures not usually associated with cavitation issues otherwise. Suction bells inferred verticals (whole thread is mostly about verticals). Specially designed strainers designed to prevent pre-rotation... obviously vortex formation prevention.

All that said vortexing to me and not cavitation potential unless the reference to cavitation was made to what happens next when air bubbles do get ingested into a pump suction, but I am a learner here.

rmw

 

[Artisi]

rmw
The matter of air ingestion and cavitation have been discussed at length in a couple of other posts - if of interest to you. No point is restarting the discussion here.

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]

I realise this is well away fromm the OP's subject of pump reliabilty - but have attached a link air entrainment and cavitation anyway.

http://www.eng-tips.com/viewthread.cfm?qid=285396

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.)

 

[rmw]

The thread is well off course although the discussion does go to the point about the OP's question of reputation/reliability/service when an otherwise perfectly good pump is misapplied and then gets a reputation as giving poor service.

Once while in a meeting at a major consulting firm, I witnessed a group of B-J product executives and their sales people get up to walk out of a meeting where the consultant's engineers were about to ignore their requirements for a properly designed sump and make a serious mistake. It was a good lesson to this young engineer and a good example of a company more concerned about its reputation than just making a sale. When the engineers at the consulting house saw that they were that serious, they relented, everone sat back down, and then we all got a good tutorial on why the rules are what they are for sump design. As part of that crowd, I learned a lot that day.

Now, regarding the thread you referenced, I read through all of it - the whole food fight - and am sorry I missed it at the time. I would have weighed in about the third or fourth post from the last and reminded readers of Henry's law, but you did finally get to that science in the last post even if you didn't call Sir Henry by name.

Dissolved air can appear mid stream if something (a bend, a strainer, a control valve etc.) lowers the total presure below the saturation pressure of any of the dissolved gasses (air being a common one) enough for the gas(es) to come out of solution. The link in the last post didn't work, but the quoted words covered it. I disagree with the "...if at all" statement if the presure rise across the pump is high enough and there is sufficient length of pipe at discharge pressure for the gas(es) to redissolve. Under those conditions the air will go back into solution readily. I deal daily with a closed loop CW process where the air is in a constant "do loop" coming out of solution in the low pressure of the pump suction, making a lot of racket in the pump, and then going back into solution downstream of the pump. We have another variation of that same closed loop where there the opportunity for the piping to 'burp' the air exists while it is still in bubble form and after a while the water becomes fairly deaerated and the noise quits.

rmw

 

[JJPellin]

The concern I had was about cavitation. But not from low NPSHa. There have been some good technical papers over the years regarding cavitation from pre-rotation and suction recirculation in large vertical turbine pumps. Even if the sump is correctly designed and fully complies with Hydraulic Institute guidelines, this can occur. I have the feeling that sump design is not entirely covered by the relevant guidelines and standards. Our vane-grating baskets were intentionally designed to avoid pre-rotation. I am on vacation and don't have access to the technical papers I referred to. Vortexing was not a concern with our sumps.

Johnny Pellin