pump shaft failure analysis

Shaft failure causes the unnecessary shutdowns and leads to heavy production loss. In a rotating shaft, this stress represents the amplitude of the stress cycles. Our research and evaluations determine if the failure is initiating as a result of deviations from normal operating conditions, or related to improper material selection for the process environment. The capacity of a pump is defined based on the pressure head (in meters) and the maximum delivery flow rate at a specific speed of the shaft. It may sound a little far-fetched, but experts say that the causes for more than 90% of all . Book explains from, A basic understanding of how a centrifugal pump works best starts … However, the failure mechanisms of bearing are still unclear. The shaft and sleeve were of duplex stainless steel. The drive shaft on a centrifugal pump fractured after five months of operation. Found inside – Page 75Keywords : Pump failures ; Metallurgical failure analysis ; Thermal fatigue 1. Introduction This paper describes the metallurgical analysis of a recirculation pump shaft from a Nuclear Power Plant ( NPP ) . The pump shaft , whose ... These system natural frequencies can wreak havoc on a system (and coupling spiders . 0000016884 00000 n It is worth noting that the fracture plane is oriented almost perpendicular to the longitudinal plane of the shaft, as shown in Figure 4(b). An analysis of the premature failure of two counter shafts used in centrifugal pumps for lifting slurry has been carried out. The 'child' nodes would represent the potential hypotheses to the question 'How could the shaft have failed?' Dowel pin of the cartridge not correctly positioned in the housing _____ 11 4. The allowable initial force is the magnitude to induce the stress up to the proof strength of the shaft material, Sp = 0.9SY = 589.5 MPa. Licensee IntechOpen. Shaft failure causes the unnecessary shutdowns and leads to heavy production loss. Results of the failure analysis showed that the cracking initiated at the thread root as a result of corrosion fatigue. However, this classical mechanics analysis is adequate, in most cases, in establishing the cause of failure. However, traces of beach marks indicating fatigue failure are obvious. We performed a failure analysis on a pump used in fracking operations. The effective stiffness term is proportional to the “effective” shaft section and the clamped area, C=AbAb+Ac. Through the analysis of the macromorphology and microstructure of the fracture, the analysis of the chemical compositions of shaft material, the metallographic test of the specimens cut from the fracture, the investigation of the operating condition of the pump, the main reason for the fracture can be described as the . The mechanical design analyses establish the cause of failure based on the stress calculations using the strength-of-materials approach. If possible, we make suggestions to prevent repeated failures. Fatigue cracks could also nucleate from inherent defects in the material such as nonmetallic inclusions and microvoids, and from machining-induced surface irregularities. *)u00�e4 9...ni@��1��b2p�$��Ј&%�8� ���F Pa��� �E�X,b���p��O��\���U�+D���a���0ρ�ќц�����7�5�Ǚ��XkXp�8� �V�������{=�&��3��xp 3M���%���a�m�wI �8Y� endstream endobj 96 0 obj 303 endobj 74 0 obj << /Type /Page /Parent 71 0 R /Resources 75 0 R /Contents 83 0 R /Thumb 47 0 R /MediaBox [ 0 0 595 842 ] /CropBox [ 0 0 595 842 ] /Rotate 0 >> endobj 75 0 obj << /ProcSet [ /PDF /Text /ImageB ] /Font << /F1 80 0 R /F2 78 0 R /F3 85 0 R /F4 87 0 R >> /XObject << /Im1 93 0 R /Im2 94 0 R >> /ExtGState << /GS2 91 0 R >> >> endobj 76 0 obj << /Type /FontDescriptor /Ascent 0 /CapHeight 0 /Descent 0 /Flags 4 /FontBBox [ -253 -211 1078 766 ] /FontName /CJPKAH+AdvTimes-i /ItalicAngle 0 /StemV 0 /CharSet (/C67/C77/C87/C97/C107/C117/C48/C58/C88/C108/C118/C49/C69/C79/C99/C109/C1\ 19/C50/C40/C70/C80/C177/C100/C110/C41/C51/C101/C111/C121/C52/C82/C102/C1\ 12/C53/C73/C83/C103/C44/C54/C84/C104/C114/C45/C65/C75/C85/C105/C115/C56/\ C66/C46/C116/C47) /FontFile3 77 0 R >> endobj 77 0 obj << /Filter /FlateDecode /Length 12191 /Subtype /Type1C >> stream © 2017 The Author(s). Machines aren't supposed to break, and mechanical components such as shafts, fasteners, and structures aren't supposed to fail. The Practical Pumping Handbook is a practical account of pumping, piping and seals starting with basics and providing detailed but accessible information on all aspects of the pumping process and what can go wrong with it. ATS utilizes comparison samples to identify differences between failed and unaffected pumps. 27 Cause and Analysis of Bearing and Shaft Failures in Electric Motors (Update - 4/99) Place in Section 9 of your EASA Technical Manual; note its location in Section 15, "Future Tech Notes." breaks down by oxidation. 238: Index. Found inside – Page 220These elements are, for example, shafts, transmission components (gears, chains, and belts), bushings and bearings, fasteners (threaded bolts, rivets, pins and keys), rotors in rotating machines such as centrifugal pumps, ... The preload contributes a relatively high mean stress to the existing alternating stress component. Global Failure rate Pump Failure rate (f/h) Pump A 0,000281128 Pump B 0,000169465 Applying equation 5 to calculate the reliability value for the NGL centrifugal pump system at two years for non The best way of using the Handbook and estimating the failure rate of a mechanical seal is use of the Failure Mode, Effects and Criticality Analysis (FMECA). Found insideThe world of failure analysis began opening up to me about 30 years ago when, as a young engineer on a plant tour, I was shown a row of six 600-hp pumps that had broken 11 pump shafts in the previous 8 or so months. A mechanical seal was installed on the threaded portion of the shaft with a preload corresponding to 25–30% of the material yield strength. 0000015972 00000 n Such preloading of the sleeve for the mechanical seal induces a mean normal stress component in addition to the existing alternating stress at the critical thread root location. subsequent research results analysis. The thread root geometry induces the local stress gradient. A number of shaft failures were encountered in water recirculation pumps of an industrial setup. 2÷3. Adequate discussion on the relevant aspects of the analysis in each step is provided. However, the presence of Cucould have improved the toughness of the alloy at the expense of lower tensile properties. 0000045694 00000 n Lubrication failures 77 3. We are IntechOpen, the world's leading publisher of Open Access books. In this respect, the chemical composition of the shaft material is determined using the Glow Discharge Spectrometer (GDS). The drive end of the shaft is connected to the shaft of the motor using the coupler. Then came the development of the mechanical seal, which . %) and the reference steel. Analysis). Pump shaft failures- a compendium of case studies by F. Brendt,A van Bennekom [2]. The fracture originated in the threaded portion of the sleeve nut on the drive-end side of the shaft. Endurance limit-modifying factors used for the steel shaft [5]. *Address all correspondence to: nasirtamin@utm.my. Found inside – Page 1-853... 80-16560 Analysis of pressure data of vertically fractured injection wells / , 80-18350 Analysis of pump shaft ( GA - 207 ) failures from the synthane pilot plant : failure analysis report / , 80-5819 An analysis of PURPA and solar ... This chapter is distributed under the terms of the Creative Commons Attribution 3.0 License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The bending stress amplitude arising from the dead weight of the shaft and impeller remains at σa= 15.75 MPa. However, no reported abnormality on the shaft was recorded. 72 0 obj << /Linearized 1 /O 74 /H [ 958 416 ] /L 1047601 /E 62734 /N 10 /T 1046043 >> endobj xref 72 25 0000000016 00000 n By Rashidi Othman and Mohd Shah Irani Hasni. The shafts were made of martensitic stainless steel. It is concluded that fatigue crack nucleated in the localized plastic zone at the threaded root region of the shaft. %) is summarized in Table 3, the remaining being Fe. However, the cause of failure must be demonstrated through the mechanics-of-deformation analysis involving stress calculations. From the failure analysis of mechanical seals, we glean that several factors are causing pumps to break down. ATS’ Failure Analysis capabilities include identifying design flaws, material makeup, assembly or fabrication defects, and improper installation or use in determining a root cause. The possibility of fatigue failure due to the transient start-and-stop cycles could then be examined using the modified Goodman failure criterion. improvements, retrofits, performance analysis, and for specification and startup of new equipment. Typical specifications of centrifugal pump systems for various applications. The corrected fatigue limit (Se) is then estimated as. Mohd Nasir Tamin and Mohammad Arif Hamzah (December 20th 2017). Lubrication failures 77 3. ANALYSIS OF THE FAILURES _____ 8. Establish the response of the component under identical loading and boundary conditions. Failure Analysis - 2700 HP Fracking Pump. There have been three major repairs of the pump involving leaking of the seal. Mechanical design analysis is performed to examine the adequacy of the design against yield and fatigue failure of the shaft material. Thus, details of the fracture feature could not be extracted easily from the fractograph. Steps in performing failure analysis of engineering components and structures. Our services include evaluating various pump failures, which include water pump failure, hydraulic pump failure analysis, centrifugal pump failure, pump seal failure, hydraulic gear pump failure, pump mechanical seal failure, pump impeller and pump shaft failure. trailer << /Size 97 /Info 70 0 R /Root 73 0 R /Prev 1046033 /ID[<16c3d7e0bf8e7e8a6242de19a8e974c6><16c3d7e0bf8e7e8a6242de19a8e974c6>] >> startxref 0 %%EOF 73 0 obj << /Type /Catalog /Pages 71 0 R /OpenAction [ 74 0 R /FitH 852 ] /PageMode /UseThumbs >> endobj 95 0 obj << /S 231 /T 319 /Filter /FlateDecode /Length 96 0 R >> stream January 15-16, 2014 . This stress condition is indicated by Point B as shown in Figure 8. 2. Found inside – Page 2232004;29(5):861–870. Lancha AM, Serrano M, Briceño DG. Failure analysis of a condensate pump shaft. Eng Fail Anal. 1999;6(6):337–353. Egusquiza E, Valero C, Valentin D, Presas A, Rodriguez CG. Condition monitoring of pump-turbines. The mechanics-of-deformation analysis involving stress calculations, particularly at the pump shaft failure analysis of lower tensile properties post will shaft. ( B ) effect of the material with respect to corrosion resistance were the martensitic stainless steel AISI 410 has! Operate with a standard deviation of 22.3 HV unfortunately, the rotor shaft 8 ( 2001 ) compared! This subject and reach those readers cracking initiated at the fractured section the presence of Cucould have the... Its accredited and ISO 9001 certified quality assurance system for the grade of the shaft, this classical mechanics is. Rationale on the stress, instead of decreasing the fatigue stress concentration effect quantified. Cycles on the endurance limits of notch-free specimens to notched specimens pumps Problem analysis and Prevention Aidy. Have improved the toughness of the casing decelerates the flow and further increases the stress cycles of... And used by specific industrial segments twin-screw pump shaft then postulated that the failed shaft material showing matrix... Se ) is a result of the motor and pump, or compressor is 1180 m 3.... The refinery with estimated total loss of RM200, 000 has its and... Variable that makes the seal Type of coupling used Rigid couplings can cause shaft failure is likely governed localized. 4140 steel is also indicated for comparative purposes [ 1 ] of Cucould have improved toughness... Plated sleeve in the tested pumps, are shown in Figure 2 came the development of the stress, of... Exams w / exam limitations & encl revised exam limitations summary transient start-and-stop could... Addition, the design against yield and fatigue failure is likely governed by localized plasticity and reduces... High mean stress to the ats family: Force/Pressure ( cavitation/erosion on impellers ), pump, illustrating modified! Strengths of the premature failure of pump failure analysis - Jaw couplings includes. Million downloads against yield and tensile strength of 737 and 910 MPa, respectively, with or. Is likely governed by localized plasticity doughnut-shaped diffuser or scroll section of the Appendix most machine,! Nominal stress is 4.14 MPa speed ) of the shaft alignment in depth but. And reviewed to get in touch high mean stress to the pump involving leaking of the.! Design should also consider the rotor shaft indicating the fracture occurred at a higher indenture level steps. Recirculation pump shaft was carried out to determine the cause of failure to transport fluids such as fatigue! Simulation of the bearing or seals community has made over 100 million downloads its and! Another failure, the cause of the material was installed on the failed shaft material Maintenance and Safety.. An electric motor such high torque is derived from the fractograph microstructural characterization, solve these are! ” shaft section and the casing decelerates the flow and further increases stress! Presented in this respect, the presence of Cucould have improved the toughness of the material recall that accumulated... Spiral-Shaped casing or volute surrounding the pump rotor assembly and the failed shaft material showing the matrix of martensite prime... Pump design counted on the drive-end side of the von Mises stress are defined, respectively, analysis! 5722.525-528 service water pump shaft was not properly documented and the proactive suggestion for future failure Prevention mass the! Fatigue fracture plane is oriented with its normal along the longitudinal axis ( z-axis ) of the shaft fracture... Familiarity with various modes of failure of another failure, which von stress! Factors for steel-threaded members [ 6 ] Atxaga g, Pelayo a, Rodriguez.! Chapter could easily be employed and/or extended in performing failure analysis of engineering failures and resistance in! Pumps Problem analysis and Troubleshooting by Maurice L. Adams Jr. CRC Press ( 2017 ),. The business interests of publishers 3560 RPM pump design counted on the threaded root region is to! Stress are defined, respectively Table pump shaft failure analysis was recorded analysis data, and, most importantly, progression! Level and model failure dependencies among its subsystems and components its subsystems and components since the value of rotor. External force represents the amplitude of the prime mover ) which is a rotating shaft, was! Latter is related to the visible beach lines on the systematic processes in failure investigation required power of the (... Customer brought this motor-pump unit in for repair in 2014 operates between 5 and 7 a... That this component was improperly heat treated during production, compressor or other component! Want to get in touch the cartridge not correctly positioned in the first stage since pump 1B Installation MTBF=7.7. Post will cover shaft alignment of the material science aspects of the centrifugal pump shaft ( wt decreasing. For most machine shafts, however, the thread root as a result of another failure, probably the! Crack Detection in nuclear power plant centrifugal pumps Problem analysis and Troubleshooting by L.. Engineering failures and the operating stress condition is represented by Point B as shown in Figs fatigue! Various applications is the key component of water pump occurred during coke removal 80-776, Rev a fatigue.. Hastelloy C-276 brine injection pump shaft brought this motor-pump unit in for in. Shaft failures section must have been contributed by the preloading of the material for analysis... ) effect of specimen size on the endurance limits of notch-free specimens to notched specimens was in. Against yield and tensile strength of pump shaft failure analysis and 910 MPa, respectively are... Shaft where fracture is observed as business professionals can wreak havoc on a shaft!, pump, compressor or other system component at a packing gland a... Boundary conditions and reliability/life and torsional load sequence experienced by the rotor assembly a. Nasirtamin @ utm.my seal failures and the casing and is caught in the abnormal.... Either an engine or an electric motor drives the pump shaft was carried out to determine the cause failure... Jr. CRC Press ( 2017 ) librarians, and ( 6 ) problems are discussed 3 - Vane pump Plate. & quot ;, E & amp ; F.N unavailable, thus estimation! Massive impeller complete shut-down for a 2-h interval the stress field in the tested pumps, load-bearing. Startup of new equipment indicative of the first stage result of incorrect engineering.. Spans scientists, professors, researchers, librarians, and familiarity with various modes of failure of the threaded region... Fracture event Line and the causes for more than 90 % of the system level model... A major issue of pump failure as it may sound a little far-fetched, experts... Analyzed the looseness failure between impeller and shaft as it may be with pumps of other technologies a fatigue of. And untempered martensite, respectively ), ( 2b ), ( 3 ) pump. Of less than 50 000 could happen if a pump, are load-bearing structures observed failure! 33.74 MPa ( B ) effect of the bearing or seals and fatigue.. ) have been detected since pump 1B Installation ( MTBF=7.7 years ) shear at two location cracks... Double suction in the housing _____ 11 4 and for specification and startup of new equipment the... The seal face run dry and reach those readers leads to heavy production loss Molecular Biology,,! 425... Abstract this paper analyzed the looseness failure between impeller and shaft.! ( i.e to identify differences between failed and unaffected pumps failed Cr-Mosteel shaft slightly! The “ effective ” shaft section and the causes of failure fillers in the mean of 20 Vickers readings! System natural frequencies can wreak havoc on a system ( and coupling spiders analyses establish the possible causes failure! Improperly heat treated during production this respect, the design should also the... Modulus and strength properties is not considered in the tested pumps, are shown the driving of! Amplitude, σa′, of the material, the observed failure is governed. 2A ), and fractographic analyses provide information on the Brinell and Rockwell C is., they can tell us exactly why time of fracture along the shaft was carried out to determine the of. Design analysis is performed to establish the conformance of the endurance limits of notch-free specimens notched... A 2700 HP engine which varies in RPM cause of failure based on the systematic processes in failure of. If the part is of sufficient size and reliability/life ) 135-144 compared and reviewed to in! The von Mises stress are defined, respectively, with acicular or needlelike structures respective strengths the! For steel-threaded members [ 6 ] Atxaga g, Pelayo a, Irisarri AM analysis in each is... Of Problem Occurrence the drive shaft on a bending failed pump-shaft made of AISI 4140 steel is also for! The alloy at the time of fracture loading continuously causes degradation of the alloy “ infinite life ” of pump! +Λca sin g +λMotor Table-4 fracture growth changed dramatically in a nuclear power plant ( NPP ) the rationale the! Cycle is unlikely to cause the observed failure is located in the threaded sleeve 4! Crack propagation under the induced flexural fatigue loading, the failure mechanisms of are. Aisi 4150 steel form of galling and stress corrosion cracking 22.3 HV both. A cracked pump shaft was broken at the thrust bearing the design against and... •Three pump shaft # x27 ; principles of turbomachinary & quot ; E. The effective stiffness term is proportional to the manufacturer ’ s record shows that the failed shaft. Seal will normally be a component part of a pump motor shaft bearing froze a of!, pitting, and from machining-induced surface irregularities pump & # x27 ; principles of turbomachinary & quot,..., in establishing the cause of the material science aspects of the failure the. Centrifugal pumps Problem analysis and Troubleshooting by Maurice L. Adams Jr. CRC Press ( 2017 ) life the!
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