When your air-operated emergency valve is opened prior to loading you can expect a longer life span from all its components. By using the air flip switch to open the emergency valve this will allow for optimum flow with a decreased pressure drop. There is a possibility of product entering the air system if the emergency valve is not opened prior to loading. It is highly recommended that you open your emergency valve prior to loading product. Check out our online parts catalog for replacment emergency valves and a air flip switches to meet your needs. Call us at 800-859-8265 before 3:00 pm and we can ship your order that day.