Donald E. Bently (October 18, 1924 - October 1, 2012[3]) was a globally recognized authority on rotor dynamics and vibration monitoring and diagnostics,[4] and an American entrepreneur and engineer. He was best known as the founder and former owner of Bently Nevada Corporation where he performed pioneering work in the field of instrumentation for measuring the mechanical condition of rotating machinery. He founded Bently Nevada in October, 1961, and served as its CEO until February, 2002. He sold the company to GE Energy in February, 2002, and in 2017 GE merged it into Baker Hughes. It continues to design, manufacture, and market these products and services under the Baker Hughes, a GE company, brand.

Donald E. Bently
Donald E. Bently, an older business man in a suit, smiling
Donald Emory Bently
Donald Emory Bently[1]

(1924-10-18)October 18, 1924
DiedOctober 1, 2012(2012-10-01) (aged 87)
Resting placeGreenwod Cemetery, Muscatine, Iowa[2]
OccupationEngineer, inventor, businessman, philanthropist
Known forInventor of eddy current proximity transducer
Founder of Bently Nevada
Susan Lorraine Pumphrey (m. 1962⁠–⁠1981)

Following the sale of the company, Bently remained active in his other family-owned businesses representing a diverse range of interests including rotordynamics, agriculture, biofuels, real estate, externally pressurized fluid bearings, and machinery diagnostics.

Early lifeEdit

Bently was born in Muscatine, Iowa, to Oliver and Mary Bently.[5] He graduated from high school in Muscatine and served in the U.S. Navy during World War II[6] with the 141st Naval Construction Battalion as a Seabee from August 1943 to April 1946.[7] The unit was primarily stationed at Hilo, Hawaii until June 1945 when it was transported to Kwajalein Atoll, Marshall Islands, where the unit helped construct the base used as a command center and base to prepare for Operation Crossroads.[8] The 141st NCB was inactivated on January 2, 1946.[9]

He returned to Muscatine and attended the University of Iowa, receiving a Bachelor of Science degree in Electrical Engineering in 1949, followed by a master's degree in Electrical Engineering in 1950.[10] Bently worked as the lead azide and mercury fulminate assembly line engineer at the Iowa Ordnance Plant in Burlington, Iowa. He then worked for North American Aviation and Rocketdyne in California. He later completed graduate-level coursework at UC Berkeley[11] while working for an aerospace company. He experimented the eddy-current sensing technology that was later the foundation of Bently Nevada Corporation. A year after relocating to Nevada, he married Susan Lorraine Pumphrey on October 5, 1962.[12] They adopted a son Christopher and were divorced in 1981.

Professional historyEdit

During Bently's brief employment North American Aviation/Rocketdyne in the mid-1950s, he assisted with research into the use of electronic sensing technologies for aircraft control systems. He thought that there was limited use for the eddy-current technology in aircraft controls, but believed the technology showed commercial promise in other areas. He received permission to use it in his own endeavors.[13] In 1956, he left the aerospace industry and gave up completing a doctorate degree to form Bently Scientific Company, manufacturing and selling eddy-current products via mail order from his garage in Berkeley, California.[13][14]:25[15]

Move to NevadaEdit

In 1960, he bought some acreage in Carson Valley that was formerly part of the valley's oldest ranches belonging to German immigrant Heinrich Friedrich Dangberg.[16] In 1961, Bently relocated the company to Minden, Nevada, and incorporated it there as Bently Nevada Corporation with three people.[17][14] By 1969, the company had 150 employees.[14]:25

Bently's was the first to successfully apply eddy-current technology for use in non-contacting displacement sensors. Often thought of as a type of electronic dial indicator, such sensors are typically used to measure very small distances between the tip of the sensor and a conductive surface, such as rotating shaft. The displacements measured are extremely small, typically on the order of several thousandths of an inch. His ideas were the beginning of an entire industry.[18]

Concentrates on rotating machineryEdit

Initially, Bently's sensors were sold mainly for laboratory rather than industrial measurements. However, beginning in the early 1960s, users began to experiment with eddy-current sensors for measuring vibration on turbines, compressors, pumps, electric motors, and other turbomachinery. This application proved to be extremely successful, allowing machinery operators a practical method of observing actual shaft vibratory motion for the first time. Soon thereafter, Bently augmented his sensors with monitoring instrumentation that accepted his sensors as inputs and provided simple visual indication of the amount of vibration. Users could set alarm levels for annunication and machine shutdown purposes when vibration levels became excessive. From that time forward, Bently began to focus his company's efforts almost exclusively on instrumentation for rotating machinery condition measurements.

Develops monitoring devicesEdit

Bently found that many of the Bently transducer systems used with third-party monitoring systems were not properly configured. After repeated challenges working with third-party monitoring systems, Bently decided to manufacture his own monitoring devices. In 1969, Bently Nevada opened its first international office in the Netherlands.[14]:27 The company grew from 1000 employees in 1980 to 1250 by 1989.[14]:30

Builds new facilityEdit

In 2001, Bently Nevada built a new $30 million, 283,000-square-foot headquarters on 26 acres (11 ha) outside Minden at Orchard and Buckeye Roads, previously known as Ferris Heights.[19][17] The new location consolidated manufacturing, design, development, marketing, and sales operations that had previously been located at eight different locations around Carson Valley.[20] In 1978, Bently acquired the Buckeye Ranch which had previously been owned by the Dengberg family. They had built brick barns on Ferris Heights that allowed them to breed sheep earlier in the year. Bently renamed the location Bently Science Park. Bricks from some of the sheep barns were incorporated into the facade of the new building.[20]

Sold to General ElectricEdit

The company's focus on rotodynamics and vibration sensors resulted in substantial growth. At age 78, Bently sold Bently Nevada to GE Energy in January 2002 for between $600 million and $900 million.[17] By then the company had 1,200 people at its headquarters in Minden, Nevada, 2,100 employees worldwide, 100 offices in more than 40 countries, and global sales exceeding $235 million USD.[17][21] Bently said he sold Bently Nevada so he could concentrate on other interests.

Other business interestsEdit

Over more than two decades, Bently bought more than 35,000 acres (14,000 ha) of land of the former Dangberg Ranch. He established Bently Ranch to raise beef cattle and alfalfa.[16]

Bently founded other businesses, including Bently Pressurized Bearing Company, which manufactured a bearing that can hold a rotating axle in place. The technology injected highly pressurized air between the bearing and the rotating machinery, preventing the axle from touching the bearing, virtually eliminating friction.[22]

Bently RotordynamicsEdit

In 1981, Bently established a pure research organization called Bently Rotordynamics Research Corporation (BRDRC or "Birdrock"). BRDRC's objective was to conduct rotordynamic research, furthering the knowledge of rotating machinery behavior, modeling techniques, and malfunction diagnostic methodologies. Its mission was considered complementary to Bently Nevada, with BRDRC focused on understanding how machinery behaved, and Bently Nevada focused on understanding and building instrumentation to measure machinery behavior.[14]:30

BRDRC made a number of important contributions to the field of rotordynamics such as a better understanding of fluid-induced instabilities, advanced models for understanding shaft crack behavior, insight into rubbing malfunctions between stationary and rotating parts, and enhancement of the rotordynamic equations via introduction of a new variable lambda (λ) which denoted the fluid circumferential average velocity ratio and more accurately modeled hydrodynamic effects. Bently was personally responsible for many of these developments, publishing his work under the auspices of BRDRC. BRDRC also introduced several new data presentation formats, such as so-called "full" spectrum plots and "acceptance region" trend plots. Its research findings were published extensively in relevant technical journals, and the research that had practical commercial applications often found its way into the Bently Nevada product line. In 2002, BRDRC was sold along with Bently Nevada to GE Energy.[10]

Other Bently businessesEdit

Bently founded Bently Agrowdynamics, which focused on environmentally sustainable agricultural practices and innovative uses of renewable resources. The company led reconstruction of Mud Lake Dam which had been damaged during the 1994 Double Springs Flat earthquake. They converted the 100-year-old earth filled dam to a rock filled structure, ensuring a supply of irrigation water for Bently Agrowdynamics’ South Ranch properties and improving the dam's resistance to earthquakes, protecting the surrounding community.[4]

Other businesses included Bently Tribology Services, Bently Biofuels, Gibson Tool and Supply, and RoMaDyn, a mechanical engineering services and diagnostics company.[1] He also held more than 38,000 acres (15,000 ha) of agricultural land in and around Carson Valley, Nevada and numerous real estate holdings in the United States and abroad.[17]

All of Bently's businesses were privately held, allowing him to focus on a long-term strategy without the pressure of quarterly stockholder reports. This also enabled him to keep his company in the front of his field technologically. He successfully competed against subsidized Japanese companies and from U.S. government-funded entities.[22] Upon Don Bently's death, his son Christopher took over his father's businesses.

Founded ISCORMAEdit

A significant amount of Bently's rotordynamic research efforts were about rotor dynamic stability. In 2001, he established ISCORMA, (International Symposium on Stability Control of Rotating Machinery), a bi-annual industry event. Bently was an active organizer and participant in all ISCORMA conferences until his death.[10]

Work with NASAEdit

His expertise also led to work for NASA. He spent 2½ years studying the area where the oxygen and hydrogen fuel pumps connect to the main engines on the space shuttle following the January 1986 challenger disaster.[23]

Philanthropy and public serviceEdit

Bently was a leader of and major financial supporter if The Institute of World Politics.[24] Bently purchased the Marlatt Mansion and two adjacent townhouses for the Institute. For the first 15 years, he rented the building to the Institute for $1.00 per year. He paid several million dollars to gut and completely renovate the townhouses and later donated them to the Institute. He also endowed the Donald E. Bently Chair of Political Economy.[22]

Bently donated several million dollars to Cal Poly State University in San Luis Obispo, California, which in Spring 2003 named the Donald E. Bently Center for Engineering Innovation to honor his substantial contributions.[18] He supported local schools in Carson Valley, and gave generously to St. Gall Catholic Church, Carson Valley United Methodist Church, and a battered women's shelter.[25] He donated land for the Western Nevada College campus in Gardenville, Nevada.[14]:2

He helped fund the building of the new 38,338 square feet (3,561.7 m2) museum facility built in 2010 at the U.S. Navy Seabee Museum at Port Hueneme, California. In 2005, he helped create a conservation easement with the Nature Conservancy that preserved the Kirman Field in northern Douglas County.[26] He also supported the Friends of Pine Creek Grist Mill, Muscatine Junior College and its Alumni Association, Muscatine Community College, the Lucille A. Carver Mississippi River Environmental Research Station Fund, and the University of Iowa.[2]


Bently was recognized with the American Society of Mechanical Engineers Frederick P. Smarro Award and R. Tom Sawyer Award, and the N. O. Mylestad Award from the Technical Committee on Vibration and Sound of the ASME Design Engineering Division. He was a Fellow and Life Member of the American Society of Mechanical Engineers. In 1992, he was made a foreign member of the St. Petersburg Academy of Engineering in Russia. The Board of Regents of the University and Community College System of Nevada recognized Bently as a 2002 Distinguished Nevadan.[4]


Bently co-authored the textbook Fundamentals of Rotating Machinery Diagnostics which is used at major universities.[10] Bently authored more than 140 papers and articles dealing rotordynamics and/or condition monitoring technologies and was granted two patents.[16][10] Many are peer-reviewed and have been published in various technical journals such as those of the American Society of Mechanical Engineers (ASME).


  1. ^ a b "Donald Emory Bently Online Obituary, October 18, 1924 - October 1, 2012". Muscatine Funeral Home - Ralph J. Wittich-Riley-Freers Funeral Home and Cremation Services. Archived from the original on 2018-08-25. Retrieved 24 August 2018.
  2. ^ a b Donald E. Bently at Find a Grave
  3. ^ "Donald E. Bently, Engineer, Industry Pioneer, Philanthropist, and Businessman Dies at 87". Business Wire. Archived from the original on 2015-09-24. Retrieved 7 November 2014.
  4. ^ a b c "Donald Bently | College of Engineering | The University of Iowa". Retrieved 27 August 2018.
  5. ^ United States Census, United States Census, 1940; Muscatine, Iowa; roll 16A, page 10A,, enumeration district 70.
  6. ^ "Donald E. Bently". Archived from the original on 2013-05-31. Retrieved 2013-04-03.
  7. ^ "Iowa, World War II Bonus Case Files, 1947-1954". Provo, Utah: Operations, Inc. 2014. Retrieved January 11, 2019.
  8. ^ Dvorak, Gregory. "The 'Martial Islands': Making Marshallese Masculinities between American and Japanese Militarism." The Contemporary Pacific Journal, 18(1) January 2008.
  9. ^ "141st Naval Construction Battalion" (PDF). Naval History and Heritage Command. Retrieved 11 January 2019.
  10. ^ a b c d e "Donald Bently - College of Engineering - The University of Iowa". Archived from the original on 2013-05-31. Retrieved 2013-04-03.
  11. ^ "Externally Pressurized Porous Gas Bearings – Bently Bearings". Bently Bearings. Archived from the original on 2012-01-25. Retrieved 2013-04-03.
  12. ^ "Carson City Marriage Records". Carson City, Nevada: Carson City Recorder's Office. Retrieved 11 January 2019.
  13. ^ a b "Donald E. Bently, Engineer, Industry Pioneer, Philanthropist, and Businessman Dies at 87". 3 October 2012. Retrieved 11 January 2019.
  14. ^ a b c d e f g "In-Memoriam – The Life of a Great Man" (PDF). Orbit. GE Oil & Gas. 33 (1): 4. January 2013. Archived from the original (PDF) on August 27, 2018.
  15. ^ "Donald Bently Obituary". Archived from the original on 2018-08-23. Retrieved 22 August 2018.
  16. ^ a b c Read, Laura. "Thinking Big on the Bently Ranch". The Furrow. Retrieved 11 January 2019.
  17. ^ a b c d e Munson, Jeff (January 28, 2002). "GE's purchase of Bently complete". Tahoe Daily Tribune. Tribune News Service. Archived from the original on 2018-08-22. Retrieved 22 August 2018.
  18. ^ a b "Bently Center". California Polytechnic State University. Retrieved 11 January 2019.
  19. ^ "Parcel Detail for Parcel # 1320-27-002-036". Douglas County Assessor. Retrieved 11 January 2019.
  20. ^ a b Carter, Sharon (December 19, 2001). "Bently breaks ground for new facility at Science Park". Archived from the original on 2018-08-22. Retrieved 22 August 2018.
  21. ^ "GE Power Systems Completes Acquisition of Bently Nevada". GE Newsroom. 25 January 2002. Archived from the original on 2018-08-22. Retrieved 22 August 2018.
  22. ^ a b c "IWP mourns the passing of longtime supporter Donald E. Bently". Archived from the original on 2018-08-25. Retrieved 24 August 2018.
  23. ^ Timko, Steve. "Bently's innovations, inventions benefited many". Obituary. Reno Gazette-Journal. Retrieved 10 October 2012.
  24. ^ "Philanthropist and entrepreneur Donald E. Bently honored at Reagan Ranch". Archived from the original on 2018-08-25. Retrieved 24 August 2018.
  25. ^ Gardner, Sheila (October 2012). "Inventor Don Bently remembered by more than 500 at memorial". Retrieved 27 August 2018.
  26. ^ "Minden industrialist, philanthropist Don Bently dead at age 87". 2 October 2012. Retrieved 27 August 2018.

External linksEdit