Rotatable valve and actuator

A rotatable pressure relief valve assembly, comprising:

• a butterfly valve having an inlet side and an outlet side;
• a spring actuator comprising a compressed spring and a piston, wherein the spring biases the spring to move along an axis and the piston terminates in a terminal end;
• a diaphragm device having a flexible membrane, wherein the flexible membrane creates a pneumatically sealed chamber within the diaphragm device, the diaphragm device further having a latch arm;
• a linkage assembly having a first end and a second end, wherein the first end is configured to engage with the terminal end of the piston, and wherein the second end is configured to engage with the latch arm;
• a pilot tube configured to transmit an inlet fluid pressure from the inlet side of the butterfly valve to the sealed chamber;
• and,
• a buckling pin mechanism having a buckling pin;
• wherein the diaphragm device is configured to translate the inlet fluid pressure into a compressive force and to transmit the compressive force to the buckling pin;
• and,
• wherein the latch arm is configured to disengage from the second end of the linkage assembly when the buckling pin has buckled, permitting the piston of the spring actuator to move along the axis along which it is biased by the spring of the spring actuator activating the butterfly valve;
• and
• wherein the spring actuator is configured to cause the piston to engage with the latch arm along an axis which is at right angles to the direction of the compressive force applied to the buckling pin by the diaphragm device.