Abstract: A pressure relief assembly includes a plurality of valve components and a cap configured to house the valve components. The cap includes a ring having a retaining portion. The pressure relief assembly includes a sensor apparatus coupled to the cap via the ring. The sensor apparatus is configured to sense whether a predetermined pressure threshold is reached. The valve components operate to relieve pressure when the predetermined pressure threshold is reached. The sensor apparatus includes a retaining portion engaging the retaining portion of the ring. A valve assembly includes a first valve apparatus and the pressure relief assembly configured to bypass the first valve apparatus. The valve assembly includes a main housing that surrounds the first valve apparatus and the pressure relief assembly. The main housing defines an aperture in which the cap of the pressure relief assembly is at least partially disposed in the aperture.

Abstract: An improved penetrometer includes a stationary ink delivery system and an improved photohead, which connects to a light source and a photodetector via two fiber optic cables. A solid state electronic circuit automatically controls the operation cycle of the penetrometer, with a single start button controlling all operations of the instrument. In particular, there is no need to reset the clock timer to zero or to adjust the 100% reflectance value prior to each test. A ratio meter displays the ratio of the current reflectance to the locked-in initial reflectance in real time as the test proceeds.