Electrodes: Suitable for 121 degrees C, 200 kPa (250 degrees F, 29 psig) minimum. Material be stainless steel or better, smooth length threaded only allowed on end, and corrosion resistant. Electrodes without gaskets are preferred. Teflon insulator media. Electrodes fitted into shrouded inserts which are directly welded onto the stand-pipe. Design to minimize faulty indication due to falling condensate into the electrodes. Electrode Cable: Pure nickel for at least the first two meters at the electrode end, with pure nickel crimps. PTFE insulation capable of withstanding up to 260 degrees C (500 degrees F). Continuous cables from the electrodes to the electronic unit. No junction boxes allowed. Overflow Water Control Valve and Controller: Open-shut electric or electronic actuated overflow control valve actuated by conductivity probe-type water level sensor and control system. Performance: When water level reaches the overflow level as set by the feedwater deaerator manufacturer, automatically open the overflow control valve to reduce the water level. Automatically close the overflow valve when the water level has been lowered to a point 100 mm (4 inches) below the high-level alarm set point. Valve operational speed shall not exceed 30 seconds for 90-degree valve movement. Controller: Automatic control be from the high-level alarm and overflow control switch system. Provide a manual/auto switch on the main instrument panel that indicates valve position. Communicate valve position with computer work station. Control valve shall fail open. A limit switch on the valve actuator shall initiate alarm on control station and in computer work station when valve is open. Control High performance butterfly valve, double offset design. Carbon steel 17-4PH steel valve body conforming to ASME B16.34, Class 150, lug style, 316 stainless steel nitrided disc. Self-energizing TFE seat providing bubble-tight shut off service on vacuum and low pressure and pressure sealed for high pressures. Bi-directional seating. Packing adjustable, chevron design with TFE seals.
Interior Coating: Coat entire interior surface, including nozzles, with water-resistant epoxy polymerized with amine adduct-type curing agent. Coating shall be suitable for continuous service at 100 degrees C (212 degrees F) immersed in demineralized water and exposed to steam vapor. Surface preparation, application of coating, number of coats, and curing shall comply with printed instructions of coating manufacturer. Ingredients of coating shall comply with U.S. Food and Drug Regulations as listed under Title 21, Chapter 1, Part 175.300. Coating shall be smooth, even thickness, with no voids. Holiday test at low voltage with wet sponge method and repair all holidays. Insulation: Field apply insulation as specified in Section 23 07 11, HVAC AND BOILER PLANT INSULATION. Water Level Indicators: SPEC WRITER NOTE: Choose the type of level indicator. //Gauge Glasses: Red line type, overlapping glasses if multiple glasses are utilized. Provide automatic offset-type gauge valves that stop the flow if a glass is broken. Drain cock on lower gauge valve. Gauge glass protecting rods.// //Magnetic Float-Flag Type Water Level Gauge: Tubular gauge with internal float using concentric magnet with stiffening rings. Float sequentially actuates magnetic flags to indicate water level. Flags anodized black on one side, gold on the other, with internal magnet. Flags magnetically interlocked with mechanical stops to allow only 180-degree rotation. Standpipe to be Schedule 40, Type 304 stainless steel. Process connections 1035 kPa (150 psig) weld neck flanges. Connections side type for maximum visibility. Bottom connection 100 mm (4 inch) flange with drain plug. Clearance between floor and bottom flange sufficient for removal of float. Switches for signals to be SPDT, 5-amp rating.// Vertical pipe type header shall be connected to top and bottom of storage tank with tank isolation valves and valved header drain. Viewable gauges shall cover entire diameter of tank. Minimum rating 121 degrees C, 200 kPa (250 degrees F, 29 psig).