1 ) What kind of work condition it will be used in ? Pls let me know it is pneumatic conveying ( positive pressure system or negative press system )or gravity conveying ?

2 ) Capacity: Feeding capacity per hour ?

3 ) Material character: what material your customers want to discharge ?  material name, bulk density, temperature, adhesion, etc

4 ) Pressure Range and working temperature ?

5 ) Flange standard and connection size, if can send me drawing & old rotary valve photos will be the best.

6 ) The requests of the motor and reducer, brand protection grade...etc ? 

7 ) Direct drive or Chain drive ?

8 ) The material of the valve customer need ? Stainless steel or Cast Iron ?

9 )  What's the quantity of the rotary valve ?