Hydro is a global leader in the pump aftermarket repairs, upgrades and engineering solutions.
Pump companies typically fall into one of two categories: the original equipment manufacturer (OEM) that design, build, and sell pumps; and smaller, local machine repair shops. But Hydro offers the pump industry the best of both worlds. George Harris, one of the original founding engineers and current CEO, explains Hydro’s unique worldwide market position: “We have developed a unique niche where we have the engineering services, the testing capabilities, and the
worldwide footprint that the large OEMs have, but we still maintain the exibility and the cost-effectiveness of the smaller companies.”
Harris also emphasizes that engineers are the heart of the company. Nick Dagres, the Vice President of Nuclear Operations in Chicago, notes that “We focus on aftermarket services and support. We implement engineering modifications to improve the performance of pumps that are out in the field.” By offering pump rebuilding, engineering, and upgrading at each service centre, Hydro can more effectively service the special needs and requirements of customers in each region. Staying close to the customer is one of the fundamental tenets of Hydro’s strategy and culture.
(Left) Hydro’s long list of services include welding-related repairs, such as performed on this 2 ½” Pacific RL IJ charging pump. (Right) A thorough quality inspection is carried out by Hydro’s detail oriented engineers.
Dr. T. Ravisundar and Dibu Chowdhury, HydroAire, Inc,. and Heinz P. Bloch, P.E., Process Machinery Consulting
Pumps & Systems
Industrial equipment users are often confronted with pump parts issues and must make choices. Handling these issues requires making experience-based decisions and prioritizing. How pump hydraulic and wear components in existing inventory are treated is an issue that merits consideration. Plant size, age, past purchasing, maintenance and storage-related practices are among the factors that affect a facility’s status with respect to operational readiness and downtime risk.
As these generally-known facts are applied on a pump component level, it is often determined that the specific pump components in the storehouse may not be the same as the components currently operating in a particular process centrifugal pump. Nor is it always the case that truly optimized components are presently installed. Therefore, the risk of experiencing unforeseen downtime can be reduced by having the right parts on hand. If the parts are truly optimized, installing them at the next opportunity will take the facility beyond being back in business—it will actually take the equipment owners to greater profitability.
To ensure that pumps will perform their intended functions, inventoried or stocked parts should be thoroughly inspected and corrected as needed prior to installation. Incoming inspection is practiced by best-of-class equipment owners and only verified-as-correct parts will be placed in the storehouse. This case study examines a real-life scenario and demonstrates essential precautions that can be taken when procuring pump hydraulic and wear components.
A Condensate Pump Repaired & Improved
During a planned outage, a nuclear power plant (NPP) sent a three-stage condensate pump to a highly experienced service center with hydraulic pump design engineers on staff. The NPP provided the hydraulic components, wear rings and bearings from its stock inventory for the pump rebuild project. The hydraulic pump design engineers at the service center performed a thorough inspection of both the disassembled rotor and the parts supplied by the NPP. A visual inspection quickly revealed that the geometry of the replacement impellers did not match the impellers that were removed from the disassembled pump (see Figure 1).
Figure 1. Cross-section of a three-stage pump created by an experienced pump repair facility for this three-stage pump. Note semi-open impellers in stages two and three.
Left: Impeller from disassembled pump
A) Leading edge of vane is straight.
B) Ring turn face to leading edge dist ~ 7/16 inch
Right: Spare impeller supplied from inventory
A) Leading edge of vane edge is curved.
B) Ring turn face to leading edge dist ~ 1inch
Paul Gray, Joe Alvey, and Jackson Simmons, Calvert Cliffs Nuclear Power Plant, Brian Hegarty, Hydro East, Simon Daou, P.E., HydroAire
A Hydro East welder repairs the impeller of a Foster Wheeler circulating water pump.
A Hydro East welder repairs the impeller of a Foster Wheeler circulating water pump.
During the 2012 refueling and maintenance outage at Unit 1 of the two-unit Calvert Cliffs nuclear power plant, near Lusby, Md., Hydro East, a subsidiary of Hydro Inc. based in Aston, Pa., supported the on-site overhaul of two large circulating water pumps. Used to supply cooling water to the plant, the Foster Wheeler vertical pumps are 8 ft 3 in. in diameter, 11 ft 5 in. tall, and weigh approximately 25,000 lb.
After the 2012 refueling outage was completed, Calvert Cliffs engineers and Hydro East’s field service team convened to discuss the project, review lessons learned, and generate plans for making the 2013 refueling outage at Unit 2 even more efficient and cost-effective. In preparation, the two groups reviewed the process that had been used in 2012 to remove, rebuild, and reinstall the Unit 1 circulating water pumps, which had been rebuilt on-site. Hydro East’s field service technicians reconditioned the impellers on location, and the Fort Smallwood Fabrication Shop gathered the other parts required to complete the rotating assemblies. The complete disassembly of an entire pump took four 12-hour
shifts, requiring one shift to clean all the reusable parts and another shift to flip and stage the parts. Each shift required a significant number of site resources as well—including security, a crane, and the crane operator—and because other tasks being performed during the outage required the use of some of these same resources, the field service technicians experienced substantial downtime.
To eliminate downtime caused by plant-induced delays—such as having to wait for the crane to become available or for spare parts to be machined—Calvert Cliffs decided to remove the Unit 2 circulating water pump rotating assemblies in one piece and send them to the Hydro East service center to be rebuilt. This plan enabled Calvert Cliffs to achieve cost savings by maximizing the availability of its internal resources and by reducing the number of shifts needed to remove
the pump assemblies from four 12-hour shifts to two. More important, lifting the assemblies in one piece eliminated two high-risk rigging activities for each pump.
Jeff Smith, Hydro Parts Solutions Inc., Dr. T. Ravisundar and Werner Barnard, HydroAire Inc.
Reverse Engineering: A Strategy for Solving Critical Part Shortages
The population of industrial pumps is aging. An article from Pumps & Systems’ August 2012 issue chronicled a repair done on an 82-year old pump still in service in a major refinery (click here to read that article). Like this refinery, many industrial operations are using pumps that have been in service 30 to 50 years or more. It is clear the infrastructure of industry is at risk due to the lack of planning by the pump owners and the more limited support from the companies that provided the pumps. To be fair to the pump OEMs, these pumps have been kept in service much longer than a pump OEM would have originally anticipated.
This article will present a case study of a recently refurbished vertical pump, show how the lack of a critical part was overcome through reverse engineering, and will share lessons learned for developing a strategy to overcome part shortages for old or obsolete pumping equipment.
Critical Part Shortage Identified
This single-stage vertical pump in a service water application was sent for repair by a nuclear power plant to Hydro Inc., a reliable independent pump service and engineering provider. A thorough inspection was performed, and although several important parts had to be reverse engineered and manufactured, all but one were machined parts for which raw material was available. One large cast part, a large aluminum bronze suction bowl weighing more than 500 pounds, was identified as the “critical delivery” issue.
Severely eroded suction bowl (Photo Courtesy of Hydro Inc.)
Hydro has a highly-skilled in-house engineering team that utilizes process control procedures for reverse engineering under their NUPIC-Audited Quality Assurance Program. Hydro’s organization is one that understands that reverse engineering is NOT the same as “replicating”. Hydro’s engineering team evaluated the critical characteristics of the component, which is essential to developing a replacement part that will meet the same form, fit, and function as the original.
During the last 20 years of my career, my main focus was on the refining and chemical industries. As I approached retirement last year, I was allowed to make some comments for Pump and Systems related to the problem facing those industries as it relates to the availability of “replacement parts” for pumps that have moved into the age range of 40 plus years; namely, we have a nationwide infrastructure problem if we do not find ways to extend the lives of hundreds of thousands of pumps by having parts availability.
After a brief retirement, I was fortunate enough to find another role to play in the same capacity but more so in the utility industry for both fossil and nuclear power plants. I was actually not surprised to find the same problem; pumps are getting so aged that parts are no longer available. If you give this a little thought you will probably come to the same alarming opinion…..we have a problem that is nationwide and is not industry specific.
Just today I visited with a utility company executive who confirmed that this is a problem that is already large and one that will grow AND that thus far there are few initiatives to address the problem. Most people say that when the pump ends its useful life, it will simply be replaced. This ignores the additional and often very considerable capital cost involved in replacing the pump beyond the cost of the pump itself; such as motors, piping, foundations, interruption in service, etc.
The purpose of my comments is to bring light to this problem and to answer a few simple questions:
Who is responsible for addressing the problem? While many will say this is the fault of the OEM and that they should address it, that is simply not correct. The OEM originally sold the pump noting a useful life of 20-25 years. Many pumps are decades older than that. The companies that originally bought the pumps have enjoyed service well beyond the original estimated useful life of the pumps. Our company recently rebuilt a pump that was 82-years old. The owner of that pump should look back on the purchase of that pump as a real bargain. The current owners of these older pumps should accept responsibility for addressing this problem.
Bill Rademacher and Jarrod Streets, BP, Jeff Johnson and William Gottschalk, Hydro Inc.
Pumps & Systems
Photo provided by BP of four IR 24 HV bottom-suction pumps and one IR 24 FV pump (P-15) in BP Whiting Refinery’s water station on Lake Michigan
Positioned on the shores of Lake Michigan are two stations that contain cooling water pumps which feed cooling water to BP’s Whiting Refinery. The #1 water station contains four IR 24 HV pumps, which are large, single-stage, double-suction, horizontal split case pumps. Four pumps in station #1 (P-11, P-12, P-13, and P-14 in the photo below) are unique in that they were designed with a bottom-suction configuration.
Photo provided by BP of Cameron performance curve circa 1933
The rotating equipment engineers at the refinery wanted to better understand the operating characteristics of these pumps, which were originally built by Cameron in 1928. Because these pumps were installed so long ago, there was no NPSH data available and the pumps’ best efficiency point was not known.
BP’s rotating equipment engineers contacted Hydro, a reliable pump service provider with whom they had a long and positive relationship. Their initial inquiry for a pump performance test led to a review of the pumps’ operating environment. Hydro’s engineers learned that one pump was a designated spare and three of the four pumps were being run at a much lower capacity. Block valves had been used to limit the discharge pressure for the three operating pumps in an effort to prevent leaks in the cooling water piping inside the refinery.
Hydro’s engineers agreed with the refinery’s rotating equipment engineers that it would be beneficial to obtain the pumps’ best efficiency point. Running the pumps too far back on their operating curves could create internal forces that would be harmful to the pumps and decrease their operating life. For this reason, the refinery decided to pull one of the bottom-suction pumps from service to be tested. However, before sending this pump to Hydro’s independent test lab in Chicago, they seized the opportunity to make modifications that would enable the vintage pump to meet current standards.
The pump was promptly sent to Hydro and a comprehensive engineering analysis was performed. Hydro’s engineers communicated with the refinery’s rotating equipment engineers to determine the modifications and upgrades that could be made.
John Neely, General Manager, HydroAire Field Service
Pumps & Systems
A nuclear power plant required field service support for their high energy multi-stage diffuser barrel pump when a feeler gage became lodged inside the pump element. The station had been experiencing a problem with a lube oil pump and the decision was made to flush the lube oil lines. During this process, the plant’s maintenance team recognized that the charge pump’s inboard pump bearing housing dowels had been bent and the rotor was not properly centered on the inboard end. As Murphy’s Law dictates, “anything that can go wrong, will go wrong”. While the rotor was being centered, a feeler gauge that had been left in the element broke off and became stuck in the inboard end at the first-stage wear ring between the inboard impeller shroud and cover wall.
Picture above shows where feeler gage had become lodged in the element.
The rotor had shuttled and rotated a considerable amount during the original attempt to remove the broken remnant. The station contacted a reliable pump aftermarket service provider who had a highly-skilled field service team with the knowledge and experience to provide support. The station wanted to get this pump back online quickly and asked the field service team to work around the clock to retrieve the broken material and complete the pump assembly. The field service team collaborated with the station’s maintenance team to resolve the issues and get the pump back into service.
A bore scope was used to confirm the piece could not be easily extracted without removing the element. The Technical Field Advisor submitted to the station an Element Removal and Installation Procedure which defined the steps for retrieving the broken feeler gage and properly installing the element back into the barrel. Upon approval of the procedure, day and night shifts were scheduled to resolve the issues.
Often all that is needed to improve a pump’s reliability and performance is to provide a high quality inspection and repair. Over time a pump may have been repaired by more than one service provider with varying levels of engineering and technical experience. Tolerances may have been opened up, fits and concentricities may have been lost and materials may have been changed, all of which contribute to reduced performance, loss of reliability and more frequent repairs.
This article highlights the opportunity seized by a coal-fired power station to upgrade a Westinghouse Vertical Pump during the repair process.
The Power Plant’s Unit #4 “Alpha” Circulating Water Pump was scheduled for repair and in the process of removal, the sister pump #4 “Bravo”, exhibited severe vibration and failed in a manner which was believed to have been a result of a broken shaft. The Alpha pump was put back into service and the Bravo pump removed and sent to the repair facility for inspection and emergency repair.
Observed Pump Condition:
The general condition of the Bravo pump when received at the repair facility was much worse than anticipated with the top column flange broken about half way around. The entire pump had been hanging from this broken joint leaving a gap of ¼” to ½” at the opening. The keyed coupling (internal to the pump) used to join its two shafts was broken in several pieces, the shaft journals were severely worn to one side and the impeller vanes & suction bell liner surface were also severely worn as expected, considering the significant pump damage.
After disassembly of the pump, it was also observed that the shaft enclosing tubes had spun in their fits due to not being fitted with any anti-rotation mechanism. This rotation caused damage to the ‘O’-ring fit areas at both ends of the enclosing tube assembly resulting in loss of proper flush water supply to the pump bearings below the packing box. Another issue observed during inspection was that part-to-part alignment of major pump components utilized dowel pins, which are very difficult, if not impossible, to verify.
Dr. T. Ravisundar, Ravi Somepalli, and Bill Nagle of HydroAire Inc.
Pumps & Systems
An Interesting Challenge and Cause for Collaboration
A major nuclear power company approached an independent Pump Performance Test Lab in Chicago to discuss a series of tests for their Pacific 4” BFIDS in safety-related service. These auxiliary feed water (AFW) pumps were utilized in two pressurized water reactor plants to supply backup cooling water to the steam generators in the event the main feed water source was interrupted. The plants had been designed to utilize an air void between two motor operated valves to keep separate two different suction sources to the pump. The Nuclear Regulatory Commission (NRC) guidelines dictated that no more than a 2% air void could be passed through the pump to reliably assure its safety-related function. The nuclear power plant engineers believed the pump could ingest a greater margin of air without damage or impairment to pump performance. The NRC gave the nuclear power company an opportunity to demonstrate the capability of this pump by allowing them to conduct and monitor a series of transient air-void tests at the independent Pump Performance Test Lab.
The independent pump performance test lab in Chicago, IL.
Engineers Working Together to Define Test Scope
The nuclear power plant engineers worked closely with the engineers at the Test Lab and a third party engineering consultant to develop the scoping document which defined the tests needed to demonstrate the pump’s capability under a range of scenarios. To design these tests, the team first reviewed the system configuration at the plants.
For added safety, each unit at each plant had one motor driven and one diesel engine driven AFW pump. Each AFW pump had been installed and aligned through valves and piping to take suction from either the non-safety related condensate storage tank (CST) or the nuclear safety related essential service water system (SX). The SX system is the nuclear safety related system that is connected to the plants ultimate heat sink (UHS), which is raw river water. As can be imagined, there is considerable difference in the purity of the water between the CST water and the SX water. Therefore, both plants intentionally built in the air void as a provision for separating these two systems to reduce the chance of SX water contaminating the clean condensate side of the system.
After thorough review, the team issued specifications for ten different sets of test cases which encompassed several operating conditions and well over 35 test scenarios. The tests would cover injection of different void volumes into the pump operating with several variables, some of which included different flow rates, suction pressures, and pump statuses (i.e. operating pump, idle pump with a pump start while suction is being transferred, etc.).
Configuring the Test Lab
Once the scope had been clearly defined and agreed upon, the Test Lab engineers set out to configure the Test Lab in a way that would duplicate almost identically the plant’s AFW suction piping set-up. Within 10 days, the Test Lab was configured with a booster pump installed with a variable frequency drive to simulate the SX system as closely as possible so that the safety-related AFW pump could be operated within the same environment as it would function in the plant. The SX water source came from the Test Lab’s 38,000 gallon suppression tank which was fed through the booster pump. The CST, which was simulated by the Test Lab’s suppression tank, was not sent through the booster pump.
Kwa Soo Teck, Phu My 3 Power Station (Vietnam), & Chandra Verma, Hydro Australia
Pumps & Systems
Phu My 3 BOT Power Station, a Vietnamese power station using combined cycle gas turbine technology and operating at 749 megawatt capacity, had been experiencing some problems with their vertical pumps. The station asked Hydro Australia to assess the damage and assist with a solution.
The power plant in Vietnam
The vertical pumps were used for the circulating water system. The impeller material was a super duplex and the product being pumped was sea water. Over a period of three years, Phu My 3 had experienced catastrophic failures with the impellers and were unsure of the cause. The first pump was installed in Sept 2003 and the first blade failed in September 2008; the second failure occurred in Sept 2009 and a third failure occurred in June 2010.
On viewing the damaged impellers, which weigh 850 kilograms, it was obvious the quality was poor. The first step in the process was to send over an engineer with a Romer Arm, a 3D coordinate measuring instrument, to reverse engineer the impeller. This data could be used to analyse the existing impeller design.