All he designed was a hole.

Robert Bunsen did not invent the Bunsen burner, he merely added a hole, which let air mix in the flammable gas and create a clean hot flame. Bunsen has done much more that we probably know, to further our understanding of science. Naming an important equipment in a chemistry lab is probably the least we can do to honour him. Bunsen's chemical of choice was Arsenic based cacodyls, a malodorous, toxic spontaneously flammable liquid compound. Bunsen wrote that the compound caused him to hallucinate, produce instantaneous tingling, giddiness, insensibility and his tongue became covered with a black coating. Probably to protect himself, he developed what is today the best antidote to arsenic poisoning- Iron oxide hydrate. Despite this, Bunsen's experiment resulted in an explosion of a glass beaker and the arsenic made him half blind for the next sixty years of his life.
After the accident, Bunsen dropped Arsenic from his experiments and investigated geysers and volcanoes by hand collecting their vapours and boiling liquids. He discovered how geysers build up pressure and blow and built a model in his lab too. But his greatest invention was yet to come. In 1850's Bunsen worked at the University of Heidelberg and invented the spectroscope- his biggest contribution to the advancement of science. Every element produces sharp, narrow bands of coloured light when heated. For example hydrogen emits one red, one yellowish green, one blue and one indigo band. So if you heat up any substance and it emits those colours, you can bet you life, that it contains hydrogen. To build a spectroscope, Bunsen along with a student took a cigar box, and mounted a prism inside. Then they attached a broken telescope to peer inside and look for colours. The only thing he did not have is something to generate very hot flames, hot enough to excite elements. So he invented the device, for which we all know him so well. He took a primitive gas burner, and added a hole, with a valve to control air flow. In the old burner, air mixed with the flammable gas once it came out of the nozzle of the burner. By adding the hole, Bunsen's burner was mixing the air well before combustion and that made all the difference.
Using this spectroscope, Bunsen and his student discovered two elements;Caesium (Cesium in America) and Rubidium.
Just before we finish, Bunsen also mentored three personalities who made it big in chemistry. One was Dmitri Mendeleev, the Russian who designed the modern Periodic table the second was Julius Lothar Meyer, a German who among other things discovered that red blood cells transport oxygen by binding it with haemoglobin and the third was French- Paul Emile Francois Lecoq de Boisbaudran, who discovered the element Gallium.
Before I finish, the student mentioned above with whom Bunsen, invented the spectroscope and discovered 2 elements was Gustav Kirchhoff. He also discovered the laws of electric charges in a network and the Kirchhoff laws are named after him