Patent attributes
A device includes a housing having a bore formed axially therethrough. The housing includes a stop that protrudes radially inward proximate to a lower end of the housing. The device also includes a lower piston positioned in the bore. The lower piston is configured to move axially within the bore in response to a pressure differential across the lower piston. The lower piston is prevented from passing out through the lower end of the housing by the stop. The lower piston has a lower piston hole formed therethrough. The device also includes an upper piston positioned in the bore. The upper piston is configured to move axially within the bore in response to a pressure differential across the upper piston. The upper piston has an upper piston hole formed therethrough. The device is configured to receive a fluid in the bore, between the upper and lower pistons.
