Solutions for Obsolete Parts

Written by: Jeff Smith, Hydro Parts Solutions Inc.
Publisher: Pumps & Systems / February, 2013

 

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.

The Situation

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.

Continue reading

Upgrades Maximize Efficiency of 82-Year-Old Pump

Written by: Bill Rademacher and Jarrod Streets, BP, Jeff Johnson and William Gottschalk, Hydro Inc.
Publisher: Pumps & Systems / August, 2012

 

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.

 

Continue reading

Benefit from Experienced Field Service Professionals

Written by: John Neely, General Manager, HydroAire Field Service
Publisher: Pumps & Systems / May, 2012

 

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.

Continue reading

Repair is an Opportunity to Improve Pump Performance

Written by: Bob Bluse, Hydro East Inc.
Publisher: Pumps & Systems / February, 2012

 

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.

 

Background:

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.

 

Continue reading

Air Void Testing for Safety-Related Feed Pumps in Nuclear Power Plants

Written by: Dr. T. Ravisundar, Ravi Somepalli, and Bill Nagle of HydroAire Inc.
Publisher: Pumps & Systems / December, 2011

 

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.

 

Continue reading