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Searching the Derwent Manual Code Field

Enter one or more manual codes connected with search operators. You can enter complete manual codes or partial manual codes using wildcards.

Alternatively, click the search aid link to look for specific codes to add to your search.

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About Derwent Manual Codes

Derwent Manual Codes are assigned to patents by Derwent's indexers. They are used to indicate the novel technical aspects of an invention, and also its applications. Using manual codes to create a detailed search strategy can significantly improve the speed and accuracy of searching.

Manual codes are arranged in hierarchies where there is a broad or general code at the top of the hierarchy followed by subdivisions of the codes into more specific categories.

For example, the manual code J07 is defined as "Refrigeration; ice; gas liquefaction/solidification." The manual code is broken down into four subdivisions:

• J07-A – Refrigeration machines, plants, or systems, combined heating and refrigeration systems
• J07-B – Freezing of (semi)liquids
• J07-C – Refrigerators, cooling, and freezing apparatus
• J07-D – Gas liquefaction, solidification, or separation by pressure or cold

Each of these is further broken down into more specific subdivisions. For instance, J07-B02 is specifically about "ice or snow production for special purposes."

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Search Examples

• H01-B* finds patent records within the hierarchy of the Petroleum/Drilling manual code.

• H01-B01* finds patent records within all subcategories of the marine structures and equipment manual code.

• H01-B01D* finds patent records within the semi-submersiable platforms manual code subcategory.

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Search Tip

When performing a search using manual codes, use the asterisk (*) character. For example, searching for J07-B finds patents that have not been assigned to one of the subdivisions within the J07-B hierarchy while J07-B* finds those patents as well as all patents within all subdivisions in the J07-B hierarchy.