Abstract: A safety relief valve provides for the equalization of backpressure across a valve spindle by providing for flow of fluid between equal sized upper and lower surfaces of the spindle in order to render the valve set point independent of backpressure, such that opening characteristics are controlled solely by the setting of the valve control spring. A seal preferably formed of TEFLON® is provided to prevent the escape of fluid from the valve body, which would otherwise adversely affect the pressure balance between the upper and lower surfaces.

Abstract: The present invention provides a method and conversion kits, that include all necessary components, to convert any style existing prior art fume hood into a stable vortex high performance low airflow fume hood that can accommodate varying size prior art fume hoods without altering the fume hood envelope or customizing the conversion kit. The articulating rear baffle can be lifted out for cleaning debris that collects in baffle conduit. The conversion can be accomplished without drilling mounting holes into an asbestos liner and can be applied on any size or style prior art fume hood. The present invention also provides a new fume hood incorporating the features of the method and kit.

Abstract: A surge relief valve comprising a main valve body having a dome port and an inlet port. The inlet port is in fluid communication with a first fluid. The invention further includes a dome reservoir connected to the main valve body via the dome port and arranged to hold a second fluid, a piston located in the main valve body, the piston in fluid communication with the reservoir, and a dampening ring positioned around the circumference of the piston operatively arranged to dampen the piston, wherein the first fluid exerts an upward force on the piston, the second fluid exerts a downward force on the piston, and the piston is arranged to move in response to a differential in the upward and downward forces, wherein the first and second fluids are isolated from one another.

Abstract: A safety relief valve provides for the equalization of backpressure across a valve spindle by providing for flow of fluid between equal sized upper and lower surfaces of the spindle in order to render the valve set point independent of backpressure, such that opening characteristics are controlled solely by the setting of the valve control spring. A seal preferably formed of TEFLON® is provided to prevent the escape of fluid from the valve body, which would otherwise adversely affect the pressure balance between the upper and lower surfaces.

Abstract: A surge relief valve comprising a main valve body having a dome port and an inlet port. The inlet port is in fluid communication with a first fluid. The invention further includes a dome reservoir connected to the main valve body via the dome port and arranged to hold a second fluid, and a piston located in the main valve body, the piston in fluid communication with the reservoir, wherein the first fluid exerts an upward force on the piston, the second fluid exerts a downward force on the piston, and the piston is arranged to move in response to a differential in the upward and downward forces, wherein the first and second fluids are isolated from one another.

Abstract: A non-flowing pilot valve is disclosed having a sense piston assembly (16) and a feedback sleeve (40) co-axially mounted within a valve body (12). A dome-line chamber (32) and an exhaust-line chamber (34) are isolated from each other by a feedback sleeve top shoulder (48) contacting a pop seal (52) on the valve body (12) below set pressure. At a few percentage points of inlet (19) pressure below set pressure, a reseat seal of a foot (20) portion of the sense piston (16) contacts the bottom shoulder (48) of the feedback sleeve (40) thereby closing off the dome-line chamber (32) from below and above and “locking in” dome line pressure. An increase in inlet (19) pressure above set pressure causes the sense piston (16) to move up simultaneously carrying feedback sleeve (40) with it thereby opening the dome-line chamber (32) to the exhaust-line chamber (34) below the open top shoulder (48).

Abstract: A system for optimizing the flow of air through a fume hood by dynamically controlling the air flow to provide a stable vortex in the vortex chamber of the hood, the optimum condition for minimizing backflow of fume-laden air through the hood doorway. A highly-sensitive pressure sensor disposed at a critical location in the vortex chamber sidewall senses minute variations in vortex pressure indicative of turbulence and sends signals via a transducer to an analog controller which uses proportional integral and adaptive gain algorithms to formulate output signals to an actuator which adjusts dampers in the hood to change the airflow into the vortex. The system operates in feedback mode and seeks a minimum in the amplitude of the sidewall pressure variations, indicating that turbulence has been eliminated and that a stable vortex exists. The pressure sensor signals can also be directed to an alarm to signal an off-standard and potentially dangerous condition.

Abstract: The flow of air through a fume hood is optimized by producing a bi-stable vortex within the vortex chamber of the fume hood regardless of sash movement. A bi-stable fume hood optimizes capture face velocity to minimize backflow of fume laden air through the hood sash opening. This bi-stable vortex fume hood reduces the energy consumption up to sixty percent versus the present day mono-stable vortex fume hoods. The bi-stable vortex fume hood utilizes a vortex pressure control system to reposition top, center, and bottom slot openings of a baffle in the hood. This baffle moves the bi-stable vortex away from the fact when the sash is fully opened and creates a clearing action near the work surface as the sash is closed. The fume hood's airfoil is placed inside the fume hood chamber and the airfoil has multiple entry pattern, one of which turns the vortex up and away from the open sash window. The other creates flow which washes the work surface of the hood.

Abstract: A pilot operated safety relief valve (14) has a main piston valve member (60) mounted for reciprocal movement between open and closed positions. The lower end of piston valve member (60) has a seat retainer (87) to retain an annular seat (89) therein. An interchangeable plug (93) is removably connected by bolt (97) to seat retainer (87) and piston valve member (60). Plug (93) extends within the inlet (50) to form a restriction within the inlet (50) defining an angular orifice (99) in the open position of the piston value member (60) for controlling discharge fluid flow. Different size plugs (93, 93A, 93B) as shown in FIG. 4 may be utilized in order to provide the desired orifice size for annular orifice 99 as illustrated in FIG. 4.

Abstract: A pilot operated safety relief valve assembly including a main safety relief valve (14) and a pilot valve (36) connected directly to the relief valve (14) is disclosed. Main safety relief valve (14) has a planar mounting face (76) in contact relation with opposed mating mounting face (78) of the pilot valve (36). Dome ports (72 and 84) in contacting planar faces (76, 78) are in alignment with each other without any tubing therebetween. Exhaust ports (74 and 86) in contacting planar faces (76, 78) are in alignment with each other without any tubing therebetween. Inlet sensing ports (75D, 75E, 65D, 65E) as shown in the embodiments of FIGS. 9 and 10 in contacting planar faces (76D, 76E, 78D, 78E) are in alignment with each other without any tubing therebetween. A fluid pressure pickup fitting (48) has a port (118) which communicates with the fluid passage (50) to the pressure vessel. A test connection (120) is connected to the fluid pressure pickup fitting (48).

Abstract: A pressure relief valve (10) for a pilot operated fluid system (FIG. 4) for a pressure vessel (12). Pressure relief valve (10) has a valve body (14) forming a valve chamber (16) accessible by upper cover plate (24). A cylindrical housing (32) is mounted in the valve chamber (16). A valve stem (38) has a diaphragm assembly (40) on its upper end and a valve assembly (42) on its lower end. Diaphragm assembly (40) includes a rolling loop diaphragm (44) fitting between opposed surfaces (36, 60) of housing (32) and piston member (56). A circular guide (66) on valve stem (38) fits within housing (32) for guiding the movement of the valve stem (38). Valve assembly (42) is connected to valve stem (38) about a ball and socket joint formed by ball (70) on the valve stem (38) and a socket (84) on the valve assembly (42).

Abstract: A system for optimizing the flow of air through a fume hood by dynamically controlling the air flow to provide a stable vortex in the vortex chamber of the hood, the optimum condition for minimizing backflow of fume-laden air through the hood doorway. A highly-sensitive pressure sensor disposed at a critical location in the vortex chamber sidewall senses minute variations in vortex pressure indicative of turbulence and sends signals via a transducer to an analog controller which uses proportional integral and adaptive gain algorithms to formulate output signals to an actuator which adjusts dampers in the hood to change the airflow into the vortex. The system operates in feedback mode and seeks a minimum in the amplitude of the sidewall pressure variations, indicating that turbulence has been eliminated and that a stable vortex exists. The pressure sensor signals can also be directed to an alarm to signal an off-standard and potentially dangerous condition.