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.
To search the literature for patents you could use the resources in the 'Material type--Patents' category on MetaLib (easily accessed via the Quick search > Articles & databases option of the Library home page), which includes some free patents databases. The British Library's Patents pages also provides links to these free patents databases and is a good place to find out more about patents and intellectual property. Alternatively, the University of Bristol's Research & Enterprise Development Division has a useful web page on patent searching. 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, is in the PATLIB network of patent information centres and keeps sets of British and some European patents. Many of these are not full patents, but are abridged.