Abstract: A typical embodiment of the invention provides a means for protecting delte instruments from damage. A flexible membrane separates two chambers in which, during ordinary operation, the fluid pressures are the same. One of the two chambers also serves as a fluid conduit in the system. Pressure loss in the system causes the higher pressure chamber to flex the membrane which closes a port in the fluid conduit chamber, thereby preventing further system pressure loss and consequent equipment damage. The membrane, moreover, can have a small bleed to permit gradual, dampened fluid pressure release.

Abstract: An apparatus for measuring the strength of a bond between a lamina and its ubstrate, or the like is shown and described. Air, or some other fluid under pressure, causes a gasket to protrude from a piston to seal the atmosphere from a chamber within the piston and the adjacent exposed lamina surface. The fluid also pressurizes this chamber to pull a loading fixture and a portion of the lamina attached thereto away from the substrate. The force required to pull the lamina from the substrate is equal to the strength of the bond.

Abstract: This tester comprises a fixture which is bonded to a coating or surface, a plate and a membrane which are sealed together along their peripheries. A hole extends through the membrane and at least into the plate for receiving the fixture so that its bonding surface is flush with the membrane. The plate has a gas opening which is connectable with a source of pressurized gas.