Edward Belknap Beale, 80, a retired Washington patent lawyer who had served as an officer in the Judge Advocate's Corps in Europe in World War II, died of a heart attack Thursday at Suburban Hospital in Bethesda. He lived in Potomac.

A native of New York City, Mr. Beale graduated from old Central High School here. He earned a bachelorhs degree in chemical engineering from Lehigh University in 1923 and a law degree from George Washington University in 1927.

Before establishing a private patent law practice here in 1936, he was an attorney for E. I. duPont deNemours and Co. and manager of the patent department at Standard Oil in Indiana.

During World War II, Mr. Beale served as a captain and later as a lieutenant colonel in the Judge Advocate's Corps.

After the war, he resumed his patent law practice in Washington. He retired in 1970.

Mr. Beale's professional memberships included the American and D.C. Bar Associations, the American Chemical Society, the Judge Advocates Association, and the American Patent Law Association.

He also was a member of the Sons of the American Revolution, the Army and Navy Club in Washington, the Congressional Country Club and the Rockville Rotary Club. He was active in the Farm Bureau and the West Montgomery Citizens Association.

Survivors include his wife, Ruth Eshelman Beale of Potomac, and a brother, William L. Beale of Albuquerque, N.M.

The family suggests that expressions of sympathy be in the form of contributions to the Potomac United Methodist Church.