The Mark 53 maintains a constant differential between the inlet pressure and the pressure loaded on top of the diaphragm. It can be used for both differential and remotely adjusted applications. The Mark 54 provides the same flow capacity as the Mark 53 but with less offset in controlled pressure due to a larger diaphragm.
 
The valve is normally closed. The force of the adjusting spring plus the pressure of the loading fluid oppose the inlet pressure acting beneath the diaphragm. As the inlet pressure overcomes the set point (the combined force on top of the diaphragm), the valve moves toward the open position, relieving the necessary pressure to maintain the set point.

• Maintains a constant differential bewteen the inlet pressure and the pressure loaded to the top of the diaphragm

• Straight-through flow for reduced turbulence and quiet operation

• Short stroke for fast response and accurate regulation

• Easily interchangeable CV’s

• Tight shutoff