In the midst of last week's Senate debate on the windfall profits tax bill, Sen. Charles McC. Mathias (R-Md.) slipped through an amendment that could produce a windfall of its own for a small Montgomery County firm owned by one-time multi-millionaire Jerry Wolman.

The only apparent beneficiary of Mathias' Amendment 734 is TVI Corp., a three-year-old company located at 4627 Howard Ave., Kensington, that has 12 employes and one product, a radiant heating panel that can supplement the existing heating plant in a home or office.

Mathias' amendment makes consumers who purchase the patented product sold under the name Energy-Kote eligible for the federal income tax credit available to taxpayers who install energy-saving devices such as storm windows and insulation.

The senior senator from Maryland said in an interview, four days after the amendment was approved by a voice vote, that he didn't realize only one company would benefit from it.

Mathias also said he never heard of Wolman, the flamboyant financier who owned the Philadelphia Eagles football team until he lost it at a bankruptcy sale 10 years ago.

Mathias said he became interested in the product after the late Joseph Danzansky, a Washington attorney and civic leader, wrote to him about "a technological breakthrough" being marketed by TVI.

The legislation "doesn't benefit just one company, but will apply to anyone who makes radiant heating panels," Mathias said. "But I am happy that one of my constituents happens to be the leader in the technology."

TVI's lawyer, Louis H. Diamond, a member of the Danzansky law firm, helped draft the amendment and said "because of the way it is defined, it affects only one company -- ours."

Diamond said other companies are experimenting with heat radiating paint, but "it's almost impossible for them to meet the standards" set out in the Mathias amendment.

Mathias introduced his amendment last Tuesday shortly after a roll call vote on a quorum call. Many senators were milling about on the floor, but few appeared to be listening.

After Mathias offered his amendment, Sen. Roger W. Jepson (R-Iowa), who wanted some time to speak on another matter, asked the presiding officer, Sen. Donald Stewart (D-Ala.), "What is the subject before the Senate now?"

Stewart passed the buck, asking Mathias to "restate the unanimous-consent request."

Mathias then explained his proposal again.

"It is to provide a residential energy credit and a business energy investment credit for low intensity infrared radiant heating systems suitable for retrofit-residential zone control installation or retrofit-spot heating installation."

Low intensity infrared radiant heating system means Energy-Kote, and retrofit means that although the panels can heat an entire house, the tax credit is given only if they are added to an existing heating system.

Mathias said the Joint Committee on Taxation estimated that granting the tax credit "would result in less than a 21 million decrease in Treasury receipts over the next seven years. This is a very small cost to our government for such a revolutionary product and the great energy savings it promises."

Diamond the TVI lawyer, said the tax committee used "pure theorization" to come up with the 21 million figure.

"We'd be extremely happy -- success would be assured," if the tax credits amount to 21 million, Diamond said.

Diamond has been seeking the special tax status for Energy-Kote for more than two years but said he got nowhere with Sen. Russell B. Long (D-La.), chairman of the Senate Finance Committee, and decided to try Mathias and Sen. Paul S. Sarbanes (D-Md.) this year.

"Mathias and his staff were quite enthusiastic," Diamond said "so we didn't push Sarbanes further."

Energy-Kote was invented by Harold Ellis, a chemist and president of Delphic Research Laboratories in Miami Beach. Ellis got Wolman interested in the device during a visit to his lab several years ago.

Wolman, a 52-year-old high school dropout who came to Washington from a small town in Pennsylvania, made -- and then lost -- a fortune in real estate. He was an early, unsuccessful investor in the John Hancock Tower in Chicago, whose financial problems helped put Wolman more than $70 million indept before he declared bankruptcy a decade ago.

He said in a brief telephone interview that he now is devoting full time to marketing Ellis' invention and hopes his son Alan, 27, will take over the company "once we get rolling." Alan Wolman is vice president of TVI.

Inventor Ellis learned of the Senate's action when called by a reporter "It applies only to my invention?" he asked."You've got to be kidding."

"Who's this guy Mathias?"