Tagged With "Centrifugal Pump"

Topic

pump Oil change before commissioning

vikramdeeps ·
Guys, for new project, Usually we preserved the equipment's (example centrifugal pump) with preservative oil during pump storage.I want to know why it is generally recommended to change the lube oil for centrifugal pump bearing before the commissioning?
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Re: pump Oil change before commissioning

vikramdeeps ·
ELECTRICPETE ,What are technical reasons for contamination of oil during pump storage at site? can you elaborate on this '' the may not be routine mixing (by running) and sampling of the oil during storage.'' How it affects the property of oil?
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Re: pump Oil change before commissioning

electricpete ·
[quote]What are technical reasons for contamination of oil during pump storage at site?[/quote]Moisture is the most common contaminant. It can come from condensation during temperature cycles. Corrosion products may be a consideration (if environment and reservoir coatings are less than ideal). Rodents or insects may find their way inside during storage, too. [QUOTE]can you elaborate on this '' the may not be routine mixing (by running) and sampling of the oil during storage.'' How it...
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Re: pump Oil change before commissioning

vikramdeeps ·
Can we check visual sample of preserved oil and if it looks good, Is still there is any need to drain the preserved oil and fill oil new before first startup of pump?
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Re: pump Oil change before commissioning

Valve ·
how big is the pump? oil replacement cost is negligible for the possible risk of operating with possibly contaminated oil. contaminated oil = degrade fast.
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Re: pump Oil change before commissioning

electricpete ·
There may be a concern the storage oil may have been contaminated based on storage environment and time. Often we don't watch these things as closely during storage and transport as during operation. Also the may not be routine mixing (by running) and sampling of the oil during storage as during operation. This may not be conclusive but it introduces a risk/concern. For many situations the tiny amount of effort/expense to change oil is well worth reducing the risk. Also in some cases, the...
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Re: pump Oil change before commissioning

Bassnjunky ·
This post may be a little late in the game. I believe most corrosion/liquid phase inhibitors are a 32 Vg. Typically this is 10% addition or less, it would seem just the viscosity alone would justify an oil change prior to commissioning a unit due to trending oil analysis. If proper storage is utilized, wouldn't you have to drain the unit to prep for installation - Bullseye, BS&W etc...Most centrifugal rotating ass'y are 1-3 qts +/-, why not start with a clean product. We currently drain,...
Topic

Centrifugal Compressor

RizwanAli ·
I am little worried about our new compressors. These are new centrifugal compressors and we have come to know that cooling tower will be required for them? We are surprised with this thing. Is it right that every centrifugal compressor require cooling tower or its is based on design and capacity of compressors?
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Re: Centrifugal Compressor

Dave Reynolds ·
Design and capacity would tell you if you need a cooling tower or not, not sure where the cutoff is but I assume about 100hp and above require a cooling tower/heat exchanger to cool the compressor oil and air stream.
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Centrifugal Pump Impeller description

Mech Mostafa Mech ·
Dear All, Pls support by how to correctly describe an impeller for ordering from any impellers manufacturers like: material , Dia ,.... ..? Not from the pump vendor Or this idea is not good and should be ordered from the pump vendor? If someone has experience with this issue pls support. Thanks
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Re: Centrifugal Pump Impeller description

Michael Meehan, CMRP, CRL ·
You need to be able to describe the impeller diameter, type (open, closed, semi-open, grinder/cutter, radial, axial, mixed-flow, or Francis vane, etc) material, shaft bore, key size, etc. Refer to Heinz Bloch's book "Pump Wisdom" for a good review of impeller characteristics and descriptions. And given a choice, I would definitely always go to the OEM for my parts provided they are a reputable manufacturer.
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Long Term Centrifugal Pump Vibration Issues

Melissa008 ·
Hi All, I am a new engineer working on my first project and wanted some feedback on some of my findings if possible. We have 8 identical closed loop cooling water systems that run medium sized centrifugal pumps. The pump performance places it quite close to the BEP operationally, but have been prematurely needing to change out bearings and mechanical seals over the last 20 years on the pumps and have had a history of high vibrations issues and running extremely noisy. There is definitely...
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Re: Long Term Centrifugal Pump Vibration Issues

Ngo Dinh ·
Vortex breaker is what I mean. As you said, the problem is occurred to 8 pumps? How arrangement of these pump, parallel or in series? each pump have the same problem? All the pumps have the same type and speed?
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Re: Long Term Centrifugal Pump Vibration Issues

Melissa008 ·
By the inlet breaker do you mean a vortex breaker or the inlet vanes? Yes we have checked the strainer but we have not checked the valves, it seems to be a problem across all 8 units so we think its something design. I attached the basic assembly drawing for it... I believe it is a flexible coupling. Thanks much!
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Re: Long Term Centrifugal Pump Vibration Issues

Ngo Dinh ·
I suspected that the motor have problem with motor bar and the bearing from motor seem to be damaged. For the pump, I would like to ask for inlet breaker at inlet of pump, is it available in pump? Have you checked the natural frequency of the pump yet? What type of coupling do you use? have you ever checked the strainer and valve condition?
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Re: Long Term Centrifugal Pump Vibration Issues

Dave Reynolds ·
Most certainly! End suction centrifugal pump will have a lot of axial thrust. If you have an image of the pump, do you have the curve to go with it? We have no idea on how your system/8 pumps work for you, more detail would be needed to better understand your situation/sketch. Do all 8 have vane pass issues? If not then the pump with high vane pass should be considered first for diagnosis. If you get motor amps and flow or discharge pressure, you can plot on the curve the point of operation...
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Re: Long Term Centrifugal Pump Vibration Issues

Melissa008 ·
Dave, Ill try to answer everything in order, thanks for the response!: Most certainly! End suction centrifugal pump will have a lot of axial thrust. If you have an image of the pump, do you have the curve to go with it?: Yes, attached. The exploded assembly of the pump is attached also. The pumps are old Ingersoll Rand 6"x5"x15" Centrifugal Pumps We have no idea on how your system/8 pumps work for you, more detail would be needed to better understand your situation/sketch. Attached also Do...
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How to detect Centrifugal Compressor Liquid Carryover

Lucman ·
Gents, What are the major signs while operation which can help us in determining centrifugal compressor liquid entrainment/liquid carryover problem? Thank you for sharing your expert knowledge.
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Re: How to detect Centrifugal Compressor Liquid Carryover

Shurafa ·
I guess if you depend on the vibration to detect liquid carryover, it might be too late. Depending on the machine's design and process, there could be ways to determine the liquid presence while the compressor in operation, such as: 1- high upstream drum level 2- high suction pressure 3- presence of liquid from compressor's drains 4- sudden and intermittent vibration Regards- Ali M. Al-Shurafa
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Re: How to detect Centrifugal Compressor Liquid Carryover

chary tatta ·
Greetings team, Very interesting question and appreciated the answer from Mr. Al- Shurafa. 1. Centrifugal compressor is oil compressed and separated the pressure gas or air is released oil free. 2. If liquid carry over, the oil drum level increases and no pressure gas or air is released. The high level alarms of oil drum is an indication of some liquid entered in compressor system. 3. The liquid can emulsify the oil system, if that is not liquified gases. 4. If such risks are there system...
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Re: How to detect Centrifugal Compressor Liquid Carryover

Lucman ·
Thank you for the reply gents. What effect liquid entrainment will have on compressor suction and discharge temperature, pressure and flows keeping in view centrifugal compressor?
Topic

centrifugal compressor lube oil pump

white walker ·
in my plant one of the centrifugal compressor having lube oil pump which is backpulled out type.recently i observed continous vibration only pump drive and nondrive around 15gE and 27gE values and velocity was below 2mm/s envlope.i think there may be flow issue problem.let me know how to analyze these type of issues.u can see the spectrum. thanks in advance.
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Centrifugal Pump Installation Procedure

Ben Kling ·
Does anyone have a good check list or procedure for installing a centrifugal pump or runner?
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Re: Centrifugal Pump Installation Procedure

pal ·
check the attachment for guide lines this is for crane but u can follow for most of the centrifugal pumps.give me ur pump model make etc., so that we give the guide lines specially.
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Re: High 20x vibration

aziz58 ·
Hi Do you have any check valve or flow control valve at discharge ? Are you sure about NPSH at suction side of pump? Maybe cavitation or other flow induced vibration
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High 20x vibration

! ! Shabir Ahmad KHAN® ·
Please see the below vibration data of a centrifugal pump & share your analysis.
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Re: High 20x vibration

John from PA ·
Interesting that the 20X is in the pump axial and essentially non existent in the motor horizontal direction. Can you advise what the bearing types are in the pump? What type coupling is being used?
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Re: High 20x vibration

! ! Shabir Ahmad KHAN® ·
Angular contact Ball bearing Deep Grove ball bearing in pump Shim type flexible coupling
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Re: High 20x vibration

Nagaraja ·
Is this a variable frequency drive. If yes can u lower the speeds by 100-200 rpm and see what happens to 20X, if not switch off the machine and a take a waterfall diagram of Pump inboard and see the influence of 20X. will it follow a linear pattern/gradually reducing trend or suddenly vanishes as soon as u switch off the pump. Just find out from the pump drawing do u have anything related to "number 20", vanes/blades etc...or may be flow related issue.. need some more trouble shooting before...
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NDE probe spurious spikes for Centrifugal Compressor

hanymaly ·
We are facing a spurious spikes from only one radial probe (X) from NDE of Centrifugal compressor driven by a steam turbine. all other 7 probes are normal (y of this radial ,x&y of compressor DE,X&Y of steam turbine DE and NDE) and no any abnormal process conditions existing. We made everything (replaced the probe,the extension cable, the SPD (surge Protection Device) and the proximitor)..all replaced by new ones but problem still exist. extension cable is in a metallic conduit..we...
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Re: NDE probe spurious spikes for Centrifugal Compressor

John from PA ·
First of all it would be good for you to add some data showing the spikes. In a case like this I always recommend that you review the direct orbits (historical) from multiple probes over a relatively long period of time to rule out electrostatic discharge (ESD). I see that you are using a steam turbine, a common prime mover when ESD occurs. I'm not going to go into great detail now but rather will attach an Orbit article I wrote many years ago on a steam turbine-gearbox-compressor train that...
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Re: NDE probe spurious spikes for Centrifugal Compressor

hanymaly ·
Thanks Mr John for your reply , I am attaching one trend showing X&Y probes trends , As you can see only X (the lower purple color) coming spurious spikes, and not Y (upper green color)..Also other Probes are normal ..Considering that probe is the NDE so it is the far one from the Steam turbine , Can electrostatic only affect it and not the other 7 probes???
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Re: NDE probe spurious spikes for Centrifugal Compressor

John from PA ·
Your trend plot is of limited value in that I can't see the amplitude or time scale. Can you improve what you post? Perhaps do a print screen and then paste into Word. Save as PDF.
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Re: NDE probe spurious spikes for Centrifugal Compressor

Shurafa ·
I tend to agree with John on the advantage to analyze the orbit plots for possible symptoms of an ESD. From the trend you have posted, I cannot see "spikes" though the plot is not clear. How much is the amplitudes at the spike and away from it? Is this problem new? Has there been any recent maintenance activity done on the unit? Regards-Ali M. Al-Shurafa
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Re: NDE probe spurious spikes for Centrifugal Compressor

vibramac ·
Is the connection between probe and extension isolated using the typical BN rubber boot?
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Re: NDE probe spurious spikes for Centrifugal Compressor

hanymaly ·
Please refer for the latest reading of 4A133X together with 4A133Y ,today 7 Dec on page 6 of the attachment. the problem in 4A133X, the following actions have been done by date: 25 Nov 15: Replaced 4A133X (Probe, extension cable and proximitor) with good result of linearity test. The reading show inconsistency after 2 days of installation (which was stable on 2 days period). 3 rd Dec 15: Replaced both SPD for 4A133X. Reading still the same. : Swap between 4A133X and 4A133Y (done in...
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Re: NDE probe spurious spikes for Centrifugal Compressor

John from PA ·
The data you present does not show ESD, but that may not mean ESD does not exist. As I said the before the direct orbit, and to a lesser degree, the time waveform, is the best way to see the spikes from ESD. Why? ESD is basically when a static buildup of electrical charge jumps to ground. The duration of the spike is key, it is only milliseconds in duration. ESD is rarely seen on a monitor, as the duration is so short. It appears in your case the duration of the spike is several minutes,...
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Re: NDE probe spurious spikes for Centrifugal Compressor

hanymaly ·
This is the same strange thing for me,Why the "Y" Probe has no problem. each extension cable in a separate metallic conduit . We checked operation log and no any correlation. All the connections used are standard Bentley Nevada parts.
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Re: NDE probe spurious spikes for Centrifugal Compressor

Shurafa ·
Usually ESD introduces violent sudden amplitude increase. Sometimes, however, the increase is small based on the voltage developed and the path through which it is released. From the trends, I've noticed that the spike's amplitude is not that high ~ 5 microns and it is like a step function. Has the probe encountered higher values during the spikes? Do you see these spikes in other systems such as DCS or a portable data collector (g.e. ADRE) . I suggest to involve your instrument people for a...
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Re: NDE probe spurious spikes for Centrifugal Compressor

John from PA ·
I think, just to clarify, it should be stated that any "violent sudden amplitude" is totally in the indication of the signal on an instrument capable of display of very short duration spikes (ADRE, System 1, other products, etc.). There isn't any violent mechanical movement of the rotor from the associated ESD spike. ESD, the jumping of a static charge built up on the rotor to ground, is simply an electrical malfunction that can be observed if the proper equipment is used. A monitor will not...
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Re: NDE probe spurious spikes for Centrifugal Compressor

chitrang.nanavati ·
What was the final conclusion here
Topic

Abnormal Behavior of Centrifugal Compressor

Faisal Ali ·
We have Steam turbine driven CO2 centrifugal compressor having 2 casings (LP/HP) with 2 stages in each Casing. Recently abnormal decrease in 3rd stage (HP) discharge temperature observed with increase in pressure. Temp reduced from 180 deg C to 140 deg C and pressure increased to 6 bar g. With this flow (Throughput) reduced upto 6 tons/hr. OEM indicated that Labyrinth seal between 3rd and 4th stage might have damaged which is causing low temp (40 deg C) 4th stage suction gas to mix with 3rd...
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Abnormal Behavior of Centrifugal Compressor

Faisal Ali ·
We have Steam turbine driven CO2 centrifugal compressor having 2 casings (LP/HP) with 2 stages in each Casing. Recently abnormal decrease in 3rd stage (HP) discharge temperature observed with increase in pressure. Temp reduced from 180 deg C to 140 deg C and pressure increased to 6 bar g. With this flow (Throughput) reduced upto 6 tons/hr. OEM indicated that Labyrinth seal between 3rd and 4th stage might have damaged which is causing low temp (40 deg C) 4th stage suction gas to mix with 3rd...
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Abnormal Behavior of Centrifugal Compressor

Faisal Ali ·
We have Steam turbine driven CO2 centrifugal compressor having 2 casings (LP/HP) with 2 stages in each Casing. Recently abnormal decrease in 3rd stage (HP) discharge temperature observed with increase in pressure. Temp reduced from 180 deg C to 140 deg C and pressure increased to 6 bar g. With this flow (Throughput) reduced upto 6 tons/hr. OEM indicated that Labyrinth seal between 3rd and 4th stage might have damaged which is causing low temp (40 deg C) 4th stage suction gas to mix with 3rd...
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Re: Abnormal Behavior of Centrifugal Compressor

SAB26 ·
Possibility of scale in form of rust/corrosion product is usually experienced in CO2 compression due to formation of carbonic acid at suction of final stage. But this deposition sometimes results increase in direct/1X vibration of compressor specially at final stage suction side. Are we experiencing any rise in vibration? If possible, please share the cross sectional drawing reference to orientation of both stage suction/discharge nozzles. This will help in further narrow downing the OEM...
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Re: Abnormal Behavior of Centrifugal Compressor

Faisal Ali ·
Dear SAB; No vibrations increase at any bearing. Vibrations trend is stable before and after the issue. Compressor impellers are In-line and not back to back. i have attached Cross sectional dwg for your further review and suggestions. Dear MICHAEL; Compressor is Barrel type which have an internal horizontally split casing and outer single casing like barrel of Pistol. So thermography will not help as all happenings are inside internal casing. Unfortunately there is no similar machine from...
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Re: Abnormal Behavior of Centrifugal Compressor

Michael Meehan, CMRP, CRL ·
This seems like it would be a good candidate for the application of some CBM technologies to see if additional information about the potential root cause can be determined. If the compressor is not heavily lagged/insulated, an infrared scan might reveal if you are indeed seeing back flow through a damaged seal. An ultrasonic survey might actually detect flow noise from that sort of defect. do you have another, similar machine that is operating properly that you can use as a baseline for...
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Re: Abnormal Behavior of Centrifugal Compressor

Michael Meehan, CMRP, CRL ·
Faisal, from a physical properties standpoint the only way to get lower temp and increased pressure is for an inter-stage leak to be occurring. Otherwise, ideal gas laws apply and the result of lower temp would be lower pressure. You are seeing a volume of cooled gas entering the discharge path which gives you the indications you are seeing. Short of a verified instrument error, you must believe your indications. For future (post repair) troubleshooting help, is there any way you could...
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Re: Abnormal Behavior of Centrifugal Compressor

RonFrend ·
Dear Faisal, I think your OEM is right. About half of the pressure is generated in the impeller and the rest is recovered in the diffuser so the pressure your 3rd stage final impeller sees is not the same pressure at the 3rd stage discharge. If the labyrinths are damaged then the higher pressure from the 3rd stage discharge/4th stage inlet could very well be leaking back into the 3rd stage causing exactly the symptoms you are describing. 1) Temperature reduced because cooler CO2 from 3rd...
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Re: Abnormal Behavior of Centrifugal Compressor

narayan ·
I agree with both the comments. Even if you think of scaling, temperature reduction is not possible. So a mechanical integrity issue between 3 and 4th stage seems to be inevitable. Do you have any vibration monitoring on these units? If it's is there, what is the response, especially in the axial displacement
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