A patent is a legally enforceable monopoly granted to an inventor in order to protect the invention from pirating and unauthorised production. The library system does not have a collection of patents. However, researchers, especially in the sciences, medicine and engineering, may find references to potentially useful patents. Helpfully, many patents are freely available online.
To search the literature for patents you could use the resources in the 'Material type--Patents' category on MetaLib, which includes some free patents databases. The British Library's Patents pages provide detailed descriptions of patents from different countries and resources to search for them, including free patents databases, and also general information about patents and intellectual property. If you would like to see a patent that is not held by the library you should consider using the Inter-Library Loan service.
The Central Library on College Green, the largest of Bristol's public libraries, holds some historical and more recent patent information.