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Sound solutions to pumping problems
S
PECIAL FEATURE
Sound s o l u t i o n s to pumping problems F o r the best p a r t o f 2 0 y e a r s , c o n d # tion monitoring technology has b e e n f a r t o o e x p e n s i v e to i n s t a l l o n r e l a t i v e l y h u m b l e p u m p i n g installations. B u t n o t a n y longer. G e r r y W o o l f r e p o r t s o n a n od~shoot o f t h a t c o n d i t i o n m o n i t o r i n g u s i n g a comb i n a t i o n o f a c o u s t i c e m i s s i o n sen. sors and existing parametric m e a s u r e m e n t s - which c o u l d c h a n g e the w a y p u m p m a i n t e n a n c e is p e r f o r m e d in the w a t e r i n d u s t r y .
P l a n t a n d m a i n t e n a n c e engineers who s p e n d m u c h of t h e i r working life a r o u n d p u m p s have u n d o u b t e d l y got a sixth sense a b o u t the condit i o n s which lead to p u m p failures - the ability to correlate a f l u c t u a t i n g p r e s s u r e gauge reading, a slightly different p u m p noise, or a c h a n g e d c u r r e n t draw o n a n a m m e t e r , a series of small i n d i c a t o r s which can be e n o u g h to tell t h e m t h a t
Acoustic sensors forming part of the AIM system fitted to chlorine dosing pumps at the Graincliff water treatment works on the edge of Ilkley Moor, Yorkshire, UK. The system gives a clear warning of impending pump failure and can alert a centralised maintenance department - especially valuable for unmanned locations.
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WORLD PUMPS SEPTEMBER 1997
there is t r o u b l e r o u n d the corner, maybe this week, maybe next. Gone are the days w h e n every e n g i n e e r i n g scheme would i n c l u d e 100% s t a n d b y plant. So w h e n failures occur, the c o n s e q u e n c e s can be more serious. Yorkshire Water has more t h a n 2000 p u m p i n g i n s t a l l a t i o n s to move water, sewage a n d sludge a b o u t the c o u n t y a n d over 10 000 installed p u m p s , some more critical t h a n others. Yorkshire Water is c o n t i n u i n g to invest in a d v a n c e d t e l e m e t r y systems t h a t e n a b l e its Regional O p e r a t i o n s C e n t r e to m o n i t o r the c o n d i t i o n of t r e a t m e n t works a n d p u m p i n g stations. Whilst this gives a n u p - t o - d a t e operating s t a t u s of a n i n s t a l l a t i o n a n d e q u i p m e n t , it does n o t give a d v a n c e d w a r n i n g of m e c h a n i c a l failure. What is required is a diagnostics system t h a t c o m b i n e s the predictive ability to detect i m m i n e n t or f u t u r e e q u i p m e n t failures with objective m e a s u r i n g t h a t can c o m p l i m e n t a n y telemetry system.
Advanced diagnostic technology To address this r e q u i r e m e n t , Yorkshire Water a p p r o a c h e d Malvern-based company, ISA Develo p m e n t s , which has come up with j u s t t h a t kind of diagnostics technology - b u t in a n affordable format for a range of i n d u s t r i e s which use p u m p s a n d compressors. ISA D e v e l o p m e n t s calls the technology the AIM system (the a p p l i c a t i o n of acoustic emission technology for intelligent p u m p monitoring). The system has its origins in aviation for detecting fatigue crack growth - the founders of the company, A n d r e w Wilkins a n d Richard Czaja, developed t h e i r t e c h n i q u e s for m o n i t o r i n g vibration in helicopters, where p r o b l e m s arising from defects can have d e v a s t a t i n g results. ISA technical director Richard Czaja explains: " To date, c o n d i t i o n m o n i t o r i n g has relied p r i m a r i l y on the a p p l i c a t i o n of v i b r a t i o n monitoring t e c h n i q u e s to identify a n d quantify faults in machines. But it has relied on expensive processing a n d a high level of o p e r a t o r skill to i n t e r p r e t results. Acoustic emission m o n i t o r i n g is s i m p l e r to carry o u t a n d is s u p e r i o r for detecting p r o b l e m s arising in slowly moving or
Copyright © 1997, Elsevier Science Ltd. All rights reserved. 0262 1762/96/$17.00
S
PECIAL FF~TURE
reciprocating m a c h i n e r y such as p u m p s a n d compressors." The theory is simple enough. A new healthy p u m p should produce an acoustic profile t h a t correlates with good performance. This profile is adjusted to incorporate the characteristics of the p u m p type a n d the media being pumped. As p u m p wear becomes apparent, this profile will change. A typical AIM system m o n i t o r s a n d logs o p e r a t i o n a l p a r a m e t e r s such as flow, pressure, power a n d speed in c o m b i n a t i o n with acoustic e m i s s i o n sensors which are used to m e a s u r e m e c h a n i c a l w e a r a n d t e a r a n d to i d e n t i f y l u b r i c a t i o n p r o b l e m s a n d cavitation.
Pump performance index An a l g o r i t h m developed by ISA provides a n overall i n d i c a t i o n of p u m p p e r f o r m a n c e b a s e d on the logged i n f o r m a t i o n a n d the p u m p profile. This P u m p Performance I n d e x is t h e n a value b e t w e e n 1 a n d 10 - t h e higher the n u m b e r , t h e closer the p u m p is p e r f o r m i n g to its initial value. For the p l a n t m a i n t e n a n c e engineer, it's simply a q u e s t i o n of looking at the liquid crystal display o n the p u m p s being m o n i t o r e d to see how they are performing. The system however does m u c h more. It c o n t a i n s a powerful d a t a logger, which stores m a n y m o n t h s of m e a s u r e d a n d calculated p u m p p e r f o r m a n c e d a t a utilising a PCMCIA card a n d provides a wide range of c o m m u n i c a t i o n o p t i o n s for t r a n s f e r r i n g historical d a t a to a host computer, SCADA or Telemetry system for f u r t h e r offline analysis. The system has now b e e n in d e v e l o p m e n t for two years with financial s u p p o r t from the DTI a n d it has already s t a r t e d to save m o n e y for Yorkshire Water. The w a t e r c o m p a n y experienced one p o t e n t i a l l y c a t a s t r o p h i c failure on a large screw p u m p used for p u m p i n g raw sewage at its K n o s t r o p sewage t r e a t m e n t works - should the bearing have failed the s u b s e q u e n t d a m a g e would have lead to r e p a i r a n d r e p l a c e m e n t costs in t h e order of £20 000. The AIM system installed at this site (the first system to be installed) detected a significant change in the P u m p Performance Index, which lead to the top b e a r i n g being s t r i p p e d down. Whilst the m a i n t e n a n c e t e a m was initially u n a b l e to locate a n y physical evidence of a p o t e n t i a l problem, a detailed i n v e s t i g a t i o n by the N a t i o n a l Tribology Laboratory identified significant fatigue d a m a g e to the b e a r i n g c o m p o n e n t s .
Integration with telemetry systems Having identified t h e earlier success of the AIM
All critical pumps at Graincliff are linked into the AIM system including this recirculation pump. system at Knostrop, Graincliffe w a t e r t r e a t m e n t works was selected to e x t e n d t h e system on different p u m p s types a n d to e n s u r e t h a t it could be fully i n t e g r a t e d with Yorkshire Water's telemetry, IT a n d r e p o r t - g e n e r a t i n g systems. Here the AIM system is installed on critical i t e m s of p l a n t for example, chlorine dosing pumps, aeration blowers and re-circulation p u m p s . This site is only m a n n e d d u r i n g n o r m a l working h o u r s - therefore a system t h a t can alert both the plant operators and maintenance to i m p e n d i n g p r o b l e m s has proved extremely valuable. To date, Yorkshire Water has installed 10 AIM systems on critical p u m p s a n d p l a n s are in h a n d for a f u r t h e r three systems to be installed on p u m p s t h a t are p a r t i c u l a r l y inaccessible such as borehole a n d s u b m e r s i b l e p u m p s .
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Conclusion
Yorkshire Water has found the AIM system to be a very powerful predictive tool. It can be used to target m a i n t e n a n c e activities a n d the potential to r e d u c e t h e a m o u n t of costly s t a n d b y p l a n t becomes more of a realistic proposition. And there are plenty of other industrial situations where the AIM system could prove j u s t as valuable. In June, the I n s t i t u t i o n of Chemical E n g i n e e r s a w a r d e d ISA r u n n e r u p prize in a n a n n u a l c o m p e t i t i o n for i n n o v a t i v e t e c h n o l o g i e s t h a t c o n t r i b u t e to safety a n d the e n v i r o n m e n t - proof, if any were n e e d e d t h a t this technology is going places.
Contact: ISA Developments, Pyndar Lodge, Hanley Swan, Worcestershre WR8 0DN, UK. Tel: + 4 4 1684 311550; Fax: +44 1684 311660; E-maih isadevs.demon.co.uk •
WORLD PUMPS SEPTEMBER 1997
PECIAL FEATURE
Sound s o l u t i o n s to pumping problems F o r the best p a r t o f 2 0 y e a r s , c o n d # tion monitoring technology has b e e n f a r t o o e x p e n s i v e to i n s t a l l o n r e l a t i v e l y h u m b l e p u m p i n g installations. B u t n o t a n y longer. G e r r y W o o l f r e p o r t s o n a n od~shoot o f t h a t c o n d i t i o n m o n i t o r i n g u s i n g a comb i n a t i o n o f a c o u s t i c e m i s s i o n sen. sors and existing parametric m e a s u r e m e n t s - which c o u l d c h a n g e the w a y p u m p m a i n t e n a n c e is p e r f o r m e d in the w a t e r i n d u s t r y .
P l a n t a n d m a i n t e n a n c e engineers who s p e n d m u c h of t h e i r working life a r o u n d p u m p s have u n d o u b t e d l y got a sixth sense a b o u t the condit i o n s which lead to p u m p failures - the ability to correlate a f l u c t u a t i n g p r e s s u r e gauge reading, a slightly different p u m p noise, or a c h a n g e d c u r r e n t draw o n a n a m m e t e r , a series of small i n d i c a t o r s which can be e n o u g h to tell t h e m t h a t
Acoustic sensors forming part of the AIM system fitted to chlorine dosing pumps at the Graincliff water treatment works on the edge of Ilkley Moor, Yorkshire, UK. The system gives a clear warning of impending pump failure and can alert a centralised maintenance department - especially valuable for unmanned locations.
L:
WORLD PUMPS SEPTEMBER 1997
there is t r o u b l e r o u n d the corner, maybe this week, maybe next. Gone are the days w h e n every e n g i n e e r i n g scheme would i n c l u d e 100% s t a n d b y plant. So w h e n failures occur, the c o n s e q u e n c e s can be more serious. Yorkshire Water has more t h a n 2000 p u m p i n g i n s t a l l a t i o n s to move water, sewage a n d sludge a b o u t the c o u n t y a n d over 10 000 installed p u m p s , some more critical t h a n others. Yorkshire Water is c o n t i n u i n g to invest in a d v a n c e d t e l e m e t r y systems t h a t e n a b l e its Regional O p e r a t i o n s C e n t r e to m o n i t o r the c o n d i t i o n of t r e a t m e n t works a n d p u m p i n g stations. Whilst this gives a n u p - t o - d a t e operating s t a t u s of a n i n s t a l l a t i o n a n d e q u i p m e n t , it does n o t give a d v a n c e d w a r n i n g of m e c h a n i c a l failure. What is required is a diagnostics system t h a t c o m b i n e s the predictive ability to detect i m m i n e n t or f u t u r e e q u i p m e n t failures with objective m e a s u r i n g t h a t can c o m p l i m e n t a n y telemetry system.
Advanced diagnostic technology To address this r e q u i r e m e n t , Yorkshire Water a p p r o a c h e d Malvern-based company, ISA Develo p m e n t s , which has come up with j u s t t h a t kind of diagnostics technology - b u t in a n affordable format for a range of i n d u s t r i e s which use p u m p s a n d compressors. ISA D e v e l o p m e n t s calls the technology the AIM system (the a p p l i c a t i o n of acoustic emission technology for intelligent p u m p monitoring). The system has its origins in aviation for detecting fatigue crack growth - the founders of the company, A n d r e w Wilkins a n d Richard Czaja, developed t h e i r t e c h n i q u e s for m o n i t o r i n g vibration in helicopters, where p r o b l e m s arising from defects can have d e v a s t a t i n g results. ISA technical director Richard Czaja explains: " To date, c o n d i t i o n m o n i t o r i n g has relied p r i m a r i l y on the a p p l i c a t i o n of v i b r a t i o n monitoring t e c h n i q u e s to identify a n d quantify faults in machines. But it has relied on expensive processing a n d a high level of o p e r a t o r skill to i n t e r p r e t results. Acoustic emission m o n i t o r i n g is s i m p l e r to carry o u t a n d is s u p e r i o r for detecting p r o b l e m s arising in slowly moving or
Copyright © 1997, Elsevier Science Ltd. All rights reserved. 0262 1762/96/$17.00
S
PECIAL FF~TURE
reciprocating m a c h i n e r y such as p u m p s a n d compressors." The theory is simple enough. A new healthy p u m p should produce an acoustic profile t h a t correlates with good performance. This profile is adjusted to incorporate the characteristics of the p u m p type a n d the media being pumped. As p u m p wear becomes apparent, this profile will change. A typical AIM system m o n i t o r s a n d logs o p e r a t i o n a l p a r a m e t e r s such as flow, pressure, power a n d speed in c o m b i n a t i o n with acoustic e m i s s i o n sensors which are used to m e a s u r e m e c h a n i c a l w e a r a n d t e a r a n d to i d e n t i f y l u b r i c a t i o n p r o b l e m s a n d cavitation.
Pump performance index An a l g o r i t h m developed by ISA provides a n overall i n d i c a t i o n of p u m p p e r f o r m a n c e b a s e d on the logged i n f o r m a t i o n a n d the p u m p profile. This P u m p Performance I n d e x is t h e n a value b e t w e e n 1 a n d 10 - t h e higher the n u m b e r , t h e closer the p u m p is p e r f o r m i n g to its initial value. For the p l a n t m a i n t e n a n c e engineer, it's simply a q u e s t i o n of looking at the liquid crystal display o n the p u m p s being m o n i t o r e d to see how they are performing. The system however does m u c h more. It c o n t a i n s a powerful d a t a logger, which stores m a n y m o n t h s of m e a s u r e d a n d calculated p u m p p e r f o r m a n c e d a t a utilising a PCMCIA card a n d provides a wide range of c o m m u n i c a t i o n o p t i o n s for t r a n s f e r r i n g historical d a t a to a host computer, SCADA or Telemetry system for f u r t h e r offline analysis. The system has now b e e n in d e v e l o p m e n t for two years with financial s u p p o r t from the DTI a n d it has already s t a r t e d to save m o n e y for Yorkshire Water. The w a t e r c o m p a n y experienced one p o t e n t i a l l y c a t a s t r o p h i c failure on a large screw p u m p used for p u m p i n g raw sewage at its K n o s t r o p sewage t r e a t m e n t works - should the bearing have failed the s u b s e q u e n t d a m a g e would have lead to r e p a i r a n d r e p l a c e m e n t costs in t h e order of £20 000. The AIM system installed at this site (the first system to be installed) detected a significant change in the P u m p Performance Index, which lead to the top b e a r i n g being s t r i p p e d down. Whilst the m a i n t e n a n c e t e a m was initially u n a b l e to locate a n y physical evidence of a p o t e n t i a l problem, a detailed i n v e s t i g a t i o n by the N a t i o n a l Tribology Laboratory identified significant fatigue d a m a g e to the b e a r i n g c o m p o n e n t s .
Integration with telemetry systems Having identified t h e earlier success of the AIM
All critical pumps at Graincliff are linked into the AIM system including this recirculation pump. system at Knostrop, Graincliffe w a t e r t r e a t m e n t works was selected to e x t e n d t h e system on different p u m p s types a n d to e n s u r e t h a t it could be fully i n t e g r a t e d with Yorkshire Water's telemetry, IT a n d r e p o r t - g e n e r a t i n g systems. Here the AIM system is installed on critical i t e m s of p l a n t for example, chlorine dosing pumps, aeration blowers and re-circulation p u m p s . This site is only m a n n e d d u r i n g n o r m a l working h o u r s - therefore a system t h a t can alert both the plant operators and maintenance to i m p e n d i n g p r o b l e m s has proved extremely valuable. To date, Yorkshire Water has installed 10 AIM systems on critical p u m p s a n d p l a n s are in h a n d for a f u r t h e r three systems to be installed on p u m p s t h a t are p a r t i c u l a r l y inaccessible such as borehole a n d s u b m e r s i b l e p u m p s .
[]
Conclusion
Yorkshire Water has found the AIM system to be a very powerful predictive tool. It can be used to target m a i n t e n a n c e activities a n d the potential to r e d u c e t h e a m o u n t of costly s t a n d b y p l a n t becomes more of a realistic proposition. And there are plenty of other industrial situations where the AIM system could prove j u s t as valuable. In June, the I n s t i t u t i o n of Chemical E n g i n e e r s a w a r d e d ISA r u n n e r u p prize in a n a n n u a l c o m p e t i t i o n for i n n o v a t i v e t e c h n o l o g i e s t h a t c o n t r i b u t e to safety a n d the e n v i r o n m e n t - proof, if any were n e e d e d t h a t this technology is going places.
Contact: ISA Developments, Pyndar Lodge, Hanley Swan, Worcestershre WR8 0DN, UK. Tel: + 4 4 1684 311550; Fax: +44 1684 311660; E-maih isadevs.demon.co.uk •
WORLD PUMPS SEPTEMBER 1997