Piston diaphragm with integral seal

In a radial diaphragm valve of the type having a valve body having a valve cavity therein, a diaphragm having a perimeter that seals the valve cavity;

• a first fluid passage in the valve body that opens to the valve cavity and a second fluid passage in the valve body that opens to the valve cavity;
• the diaphragm having a central diaphragm stem that opens and closes the valve such that the diaphragm stem is movable between a valve open and valve closed position along an axis;
• and an actuator for moving the diaphragm stem to open and close the valve, the improvement comprising:
• a backup seal located between a diaphragm seal and an actuator piston, wherein said backup seal prevents process fluid from contact with said actuator piston, when the diaphragm seal is compromised.

In a radial diaphragm valve of the type having a valve body having a valve cavity therein, a diaphragm having a perimeter that seals the valve cavity;

• a first fluid passage in the valve body that opens to the valve cavity and a second fluid passage in the valve body that opens to the valve cavity;
• the diaphragm having a central diaphragm stem that opens and closes the valve such that the diaphragm stem is movable between a valve open and valve closed position along an axis;
• and an actuator for moving the diaphragm stem to open and close the valve, the improvement comprising:
• a seal disposed on the diaphragm stem wherein said seal journals and guides the diaphragm stem in the bore, thereby facilitating alignment of said diaphragms.

In a radial diaphragm valve of the type having a valve body having a valve cavity therein, a diaphragm having a perimeter that seals the valve cavity;

• a first fluid passage in the valve body that opens to the valve cavity and a second fluid passage in the valve body that opens to the valve cavity;
• the diaphragm having a central diaphragm stem that opens and closes the valve such that the diaphragm stem is movable between a valve open and valve closed position along an axis;
• and an actuator for moving the diaphragm stem to open and close the valve, the improvement comprising:
• a groove formed in the diaphragm stem and a seal received in said groove, wherein said seal aligns the diaphragm stem independently from the alignment of the actuator.

In a radial diaphragm valve of the type having a valve body having a valve cavity therein, a diaphragm having a perimeter that seals the valve cavity;

• a first fluid passage in the valve body that opens to the valve cavity and a second fluid passage in the valve body that opens to the valve cavity;
• the diaphragm having a central diaphragm stem that opens and closes the valve such that the diaphragm stem is movable between a valve open and valve closed position along an axis;
• and an actuator for moving the diaphragm stem to open and close the valve, the improvement comprising:
• a groove formed in the diaphragm stem and a seal received in said groove, wherein said seal is located such that if the diaphragm seal is compromised, process fluid will only be exposed to inert matter.