Self-Checking Block Valve For Shutdown Systems
G. Paul Baker, Jr.
Safety Cycling Systems LLC
Denham Springs, LA
Within the petrochemical industry, the risk of violent, hazardous events caused by a chemical reaction is reduced by the use of a Safety Instrumented System (SIS). The obvious failures in a SIS cause the chemical process to shut down when no parameter has exceeded its allowable values. One component not easily checked for hidden failures is a block valve. A block valve’s ability to stop the chemical reaction can only be determined by fully stroking the valve, which shuts down the chemical process.
The patented SafetySIL valve technology allows the block valves in a SIS to be fully stroked without interrupting the flow of the reactants. It consists of two parallel valves in a “Y” manifold. A controller keeps at least one valve open at all times, while cycling between closing one valve, and then the other. A differential pressure transmitter looks for positive and negative differentials between the outlets of the valves. A calibrated amount of differential pressure cannot be present if the closed valve is not fully closed. If the proper amount and polarity of differential pressure is present, the cycling will continue. If there are any failures in any component, hidden or obvious, the cycling cannot be maintained.
Household Water Treatment Device
This new household water treatment device uses ultraviolet (UV) light to disinfect water on a container-by-container basis. It can be powered by a hand crank, as shown in the photo, or by a pedal crank, solar collectors, or connection to an electrical grid if one is available. Turning the hand crank charges the battery and powers the germicidal UV light bulb, providing disinfection for a container of water.
The only specialty parts are the germicidal bulb and its matching ballast. Any of several rechargeable batteries can be used. The estimated cost per unit is $25, when produced in bulk. If it is used to treat three batches per day of six liters per batch, and the components last five years, the cost per liter is less than 0.08 cents.