Apparatus for indicating a clogged condition of a fluid filter or the like. The apparatus includes an electrical switch structure and a pressure-responsive element carried within the chamber to be responsive to the fluid pressure differential existing across the filter. The switch includes a threaded screw element adapted to adjustably engage the fluid pressure-responsive element in the chamber which may comprise a snap action element providing a positive instantaneous indication of the pressure across the filter reaching the preselected elevated value indicative of undesirable clogging of the filter.
A pressure sensing switch for transducing the change of pneumatic pressure to an electrical signal comprises a diaphragm made of a material having a Young's modulus E of 1.0.times.10.sup.4 -2.1.times.10.sup.4 kg/mm.sup.2, a Poisson's ratio V of 0.3, a thickness t of 0.02-0.2mm, a diameter d measured at a radially inner edge of a side wall portion being 5-10mm, a ratio of a radius or curvature R measured at a deflectable portion to a diameter d measured at the radially inner edge of the side wall portion being 2.5-5, and a maximum deflection Dmax of the deflectable area being ##EQU1##
A snap action fluid pressure actuated switch, including a switch housing within which is mounted a metallic dome-shaped disc which is dimpled in its center by a predetermined pressure differential to provide a snap action, while being biased to eliminate the deformation and return the switch after the pressure differential declines. The disc is secured to a spool contact movably by the snap action of the disc into and out of electrical contact with either of a pair of contact plates to create an electrical connection between a terminal electrically connected to the metallic disc and either of a pair of terminals connected to a respective contact plate. The free end of the spool contact is piloted at its free end and adjustable fixed stops are provided to position the spool contact in the connected metallic disc at either end point of the snap action movement, while enabling adjustability in the end positions of the spool contact and the pressure conditions causing the snap action to occur.
A pressure monitoring device is disclosed which is adapted to couple a source of fluid with a tripping device. The tripping device includes a tripping switch movable between a first position in which a tripping signal is generated and a second position in which a tripping signal is not generated, and biasing means for biasing the tripping switch into the first position. The pressure monitoring device comprises pressure transmission means which is operable in a first mode and in a second mode, and coupling means having a first position and a second position. The pressure transmission means when operating in the first mode is responsive to the pressure of the fluid being monitored and when operating in the second mode is independent of the pressure of the fluid. The coupling means is operatively associated with the pressure transmission means and the tripping device for coupling the pressure transmission means to the tripping device. The coupling means transmits a pressure signal proportional to the pressure of the fluid to the tripping switch when the coupling means is in the first position and the pressure transmission means is operating in the first mode whereby the tripping device generates a tripping signal when the pressure of the fluid passes a predetermined limit. Further, the coupling means forces the tripping switch into the second position independent of the pressure of the fluid when the coupling means is in the second position.
4453416 - Abstract - Owned by The Babcock & Wilcox Company (New Orleans, LA)
An improved vortex shedding flowmeter sensor and method are disclosed. The vortex shedding sensor is a bistable element. The element is constrained to operate in a transition deflection region between two stable stages. The element tends to alternate states at the frequency of vortex shedding, thereby amplifying the input signal at low levels and extending the low range of flow rate measurement.
A process for treating bovine pericard tissue to increase resistance to biological degradation by wet-chemical processing, The wet-chemical processing consists essentially of: (i) separating any adherent fat and basal membrane from the tissue; (ii) contacting the tissue with an aqueous, alkaline solution of sodium hydroxide, potassium hydroxide, lithium hydroxide or sodium carbonate to swell the tissue; (iii) contacting the swollen tissue with an aqueous sodium chloride solution to control the swelling; (iv) contacting the tissue with a solution of a metal-ion complexing agent with a pH in excess of 11; and (v) contacting the tissue with an aqueous buffer solution having a pH of 4.5 to 6.0. Each of steps (ii)-(v) is followed by a water rinse. The pericard tissue is then dried and sterilized.
