Nearly everyone has heard someone say he had a good idea and wanted to get a patent and make some money. But often, the would-be inventor has no idea how to apply for a patent, how much it will cost or how long it will take.

A patent is a grant issued by the U.S. Patent and Trademark Office of the Department of Commerce "giving an inventor the right to exclude all others from making, using or selling his invention within the United States, its territories and possessions," according to a Patent Office brochure.

Before applying for a patent, a thorough search must be made to see if the idea has been patented or published elsewhere. This can be a lengthy process because the Patent Office has about 25 million documents on file, receives 20,000 more documents a day and processes about 115,000 applications a year.

And just because you have not seen a device on the market does not mean someone else has not thought of the idea and already won a patent, or that it has not been patented in another country. If someone has published an article on the invention, that, too, could stop you from gaining a patent.

A patent applicant, his attorney or agent can conduct a patent search in the public search room of the U.S. Patent and Trademark Office in Crystal City. The government also maintains patent depository libraries in 33 states where copies of patents can be inspected.

The Patent Office this year embarked on an ambitious plan to computerize its application, examination and issuance functions. Officials estimated that when the computers are in place in 1990, they will cut the time needed to process and issue a patent to an average of 18 months from the current 27-month average.

It is important to search foreign patents, because U.S. patent law blocks issuance of a patent if an invention has been patented in a foreign country or described in a publication anywhere in the world.

After the patent search, if you are still confident you have a novel idea, you should hire a professional patent draftsman to make the required patent drawing. The Patent Office has specific guidelines about the size, type of paper and composition of patent drawings, and if they are not met, corrections will be made by Patent Office draftsmen at the inventor's expense.

The next step is the patent specification, a legal document that describes the invention, and according to patent law, "the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor of carrying out his invention. The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention."

The application also must include the filing fee and an oath signed by the applicant stating that he believes himself to be the original inventor.

The Patent Office divides applicants into two classes for fee purposes: "small entity" -- "an individual inventor, a small business or a nonprofit institution" -- and "large entity," which includes large business and corporate applicants. The basic patent application fee is $300, which entitles the applicant to present 20 claims describing the novelty of the invention. Filing fees are reduced by half for small entities. Additional costs may be assessed for additional claims or if the application fails to meet Patent Office requirements and must be returned to the inventor for amendments.

It has been estimated that the average invention costs at least $3,000 to patent, including attorney's or agent's fees.

After the Patent Office accepts the application, the inventor is given a receipt with the serial number and filing date. The application is then routed to the patent examining group that deals with the area of technology related to the invention.

The patent examiner conducts another hand search of U.S. and foreign patents and available literature to see if the invention is new and makes a decision whether to grant a patent.

The patent examiner notifies the inventor, usually through his attorney or agent, of the decision by an "action." If the application is rejected, the "action" will explain what prior patent or patents the rejection was based on. Or the examiner may require corrections or changes in the specifications and claims, or cancel certain claims. The examiner may take up to three "actions" before either granting a patent or giving a final rejection.

According to Patent Office documents, "It is not uncommon for some or all of the claims to be rejected on the first action by the examiner; relatively few applications are allowed as filed."

The inventor can petition for reconsideration of the application by responding in writing to each of the patent examiner's objections, or he may ask for an appointment with the examiner to iron out their differences. If that fails, the inventor, through his attorney, may petition the Commissioner of Patents for a decision on the rejection, take the final rejection to the Board of Patent Appeals, or even take the case to the courts.

Once a patent has been granted, the inventor must pay a yearly fee to keep his patent in force.

Patents granted recently to residents of D.C., Maryland and Virginia: Washington, D.C.: Design Patent

Mario E. Basil. Compartmented tray and cover for food or the like. No. D 276,116. Maryland: Design Patents

Robert P. Wagster, of Easton. Foldable sawhorse. No. D 276,074.

Stanley H. Katz, of Baltimore. Coin tray or similar article. No. D 276,168.

Robert M. Tyburski, of Fairfax; Donald W. Russell, of Potomac, Md.; Brian D. Mayberry, of Alexandria, Va., and Joseph R. Kenny, of Woodbridge, Va. Combined magnetic optical character reader. No. Re. 31,692. 39 claims. Virginia Patents

Samuel A. Face Jr., of Norfolk, and Samuel A. Face III, of Newport News. Surface profile measuring device. No. 4,473,960. 13 claims.

Walter J. Denkowski, of Rustburg, and Raymond D. Regan, of Lynchburg. Valve operator de-clutch mechanism. No. 4,474,078. 7 claims.

Peter Durenec, of Annandale. Fluidic self-adjusting seal assembly. No. 4,474,106. 10 claims.

Joseph J. DeMato, of Lynchburg. Musical instrument case and holder. No. 4,474,290. 7 claims.

James T. Dennie, of Arlington. Wood stove and fireplace log handler. No. 4,474,396. 20 claims.

Yoram Houminer, and Edward B. Sanders, both of Richmond. Flavored foodstuff. No. 4,474,819. 2 claims.

William L. McGuire Jr., of Newport News; Gerald E. Paxton, and Douglas M. Wheeler, both of Hampton. Multi-mode constant potential pulsed welding apparatus. No. 4,475,028. 13 claims.

Ronald A. Sink, of Roanoke. Image intensifier tube with reduced veiling glare and method of making same. No. 4,475,059. 12 claims.

Ja H. Lee, of Newport News. High-coulomb transfer switch. No. 4,475,066. 5 claims.

Philip R. Couch, of Roanoke. Data eye monitor. No. 4,475,210. 24 claims.

Neils O. Young, of Free Union, et al. Refrigeration system with linear motor trimming of displacer movement. No. 4,475,346. 9 claims.

Moses G. Farmer, of Hampton. Model mount system for testing flutter. No. 4,475,385. 17 claims.

Charles E. Hawk, of Newport News, and Jonathan T. Whitcomb, of Hayes. High temperature mass flowmeter. No. 4,475,387. 6 claims.

Calvin H. Hand Jr., of Tappahannock; David J. Hand, of Warsaw, and John A. Careatti, of Howertonns. Bio-mass burner with grate therefor and method of operation. No. 4,475,471. 2 claims.

Worth H. Percival, of Oakton, and David N. Wells, of Arlington. Window for solar-powered hot gas engine. No. 4,475,538. 6 claims.

Richard E. Thatcher, of Chester; Horace L. Odom, of Bon Air, and Ronald L. Edwards, of Richmond. Method and apparatus for separating tobacco mixture into lighter and heavier fractions. No. 4,475,562. 13 claims.

George J. Fleury Jr., of McLean. Multi-staple cartridge for surgical staplers. No. 4,475,679. 15 claims.

D.C. Reece, of Clarksville. Automatic tension controller ball creel. No. 4,475,694. 9 claims.

Richard B. Smith, of Newport News. Mechanism for positioning workpieces. No. 4,475,726. 18 claims.

Louis Sica Jr., of Alexandria. High resolution diffraction grating. No. 4,475,792. 8 claims.

Jer-Yu Shang, of Fairfax, et al. Reversed flow fluidized-bed combustion apparatus. No. 4,475,884. 7 claims.

Frederica V. Coates, of Charlottesville. Adjustable diapers with fastening means. No. 4,475,912. 13 claims.

Richard P. Schmitt, and Vincent J. Ciccone, both of Alexandria, and William P. Gardiner, of Springfield. Multiple element fluid separation device. No. 4,476,015. 23 claims.

Ernest A. Franke, of Goode, and Frederick J. Highton, of Lynchburg. Radio transceiver. No. 4,476,575. 6 claims.

Wilbur L. Stables, of Matoaca; James J. Cooksey, of Colonial Heights, and Harry L. Newell Jr., of Richmond. Apparatus for measuring gas velocity. No. 4,476,729. 1 claim.

Lawrence K. Edwards, of Falls Church. Railway switch. No. 4,476,787. 8 claims.

George P. Diacont Jr., and James D. Grisham, both of Richmond. Feed-through folder apparatus. No. 4,476,792. 8 claims.

Jonathan P. Lee, and Clyde L. Longue, both of Flint Hill. Add-on catalytic damper assembly. No. 4,476,852. 7 claims.

John I. Peterson, and Raphael V. Fitzgerald, both of Falls Church. Fiber optic P02 probe. No. 4,476,870. 14 claims.

Andre J. Jackson, of Alexandria. Apparatus for and methods of collecting urine from laboratory animals. No. 4,476,879. 17 claims.

Joseph L. Stein, of Fairfax. Adjustable crutch. No. 4,476,885. 6 claims.

Michael Dunne, of Alexandria. Head and neck restraint system. No. 4,477,041. 10 claims.

Howard F. Callis, of Mathews. Adjustable rake head and improved handle support. No. 4,477,114. 2 claims.

James S. Frantz, of Roanoke. Security cabinet for storage of valuables. No. 4,477,130. 6 claims.

Clifton L. Spence, of Woodbridge, and Walter Lissiuk, of Silver Spring, Md. Diffusion transfer processor. No. 4,477,165. 9 claims.

Dixon Cleveland, of Vienna, et al. Method and apparatus for detecting edge welds during resistance spot welding. No. 4,477,709. 6 claims.

Daniel J. Kouba, of Manassas. Lssd compatible clock driver. No. 4,477,738. 10 claims.

Robert C. Roberts, of Lynchburg. Electrical circuit for providing an abnormal transient display system for nuclear reactor operation. No. 4,477,804. 3 claims.

Prem Puri, of Manassas, and Yogi K. Puri, of Vienna. Testing method for assuring ac performance of high performance random logic designs using low speed tester. No. 4,477,902. 8 claims.

Arthur H. Salminen, of Waynesboro. Modular bathroom installation. No. 4,477,934. 9 claims.