I don't know which company instrument you are using right now. But normally KEL+ nitrogen auto analyser make sound only while intaking NaOH and distilled water. While distillation a light sound will be there but i dont think that will disturb you. So if your instrument is making too much sound that means it needs survicing.
There is need to build sound proof structure around the machine to reduce the noise,. You can trouble shoot to identify part of equipment that needs lubrication and general servicing . Besides, there is need for proper storage to prevent people who are skillful in the use of the equipment from tampering with it