A 

 is from a family of 

 called quarter-tum 

. In operation, the 

 is fully open or closed when the disc is rotated a quarter tum. Operation is similar to that of a

, which allows for quick shut off. 

 are generally favored because they cost less than other 

 design, and are lighter weight so they need less support. In the pharmaceutical, chemical and food industry a 

 is used to interrupt product flow (solid, liquid, gas) within the process. The 

 used in these industries are usually manufactured according cGMP guidelines (current good manufacturing practice).

A 

 is from a family of 

 called quarter-tum 

. In operation, the 

 is fully open or closed when the disc is rotated a quarter tum. Operation is similar to that of a

, which allows for quick shut off. 

 are generally favored because they cost less than other 

 design, and are lighter weight so they need less support. In the pharmaceutical, chemical and food industry a 

 is used to interrupt product flow (solid, liquid, gas) within the process. The 

 used in these industries are usually manufactured according cGMP guidelines (current good manufacturing practice).