Hi, please check my portfolio, I had do a similar projects.
I think you have a great product and I will do an excellent job for you, there are others freelancers that may bid to you but they haven´t the skill for the job because there are only cad artist. I can offer what you need I work with Solidworks, Rhinoceros, 3d max, Vray, Keyshot, Illustrator, Photoshop, Corel Draw , Autocad and I do have a great sketching skills. The proposal includes 3 concepts to choose . I am looking forward to work with you on your air pump project
Feel free to contact me