Inlet orifice for a fuel pressure damper

A fuel pressure damper comprising:

• a housing defining an inlet constructed and arranged to receive fuel,
• an orifice disc at the inlet, the orifice disc including at least one orifice there-through,
• a cover coupled to the housing to define an interior space, the orifice disc being interchangeable with a different orifice disc having different sized and/or number of orifice(s),
• a flexible diaphragm having a periphery fixedly secured to at least the housing or the cover and having a freely movable central portion that divides the interior space into first and second isolated chambers, the at least one orifice communicating with the second chamber, and
• a compression spring in the first chamber and disposed between a spring receiving structure and the cover, the spring biasing the spring receiving structure and thus the diaphragm to a normal position thereby defining a volume in the second chamber, and in an operating position, the central portion of the diaphragm alone, or in combination with the spring, is constructed and arranged to dampen fuel pressure pulsations in the second chamber by varying the volume of the second chamber,
• wherein the at least one orifice has a diameter and length to ensure that pressure pulsations of a certain magnitude are prevented from entering the second chamber.