sensor shall be Cesium 137. Source head shall be designed with a spring
return off system in the event of remote cable actuator failure. Source
shall be interlocked with hopper access doors to prevent entry into hopper
unless source has been secured. Hopper access door key shall only be able
to open one pair of hopper doors.
2.12.10.1
Hopper Level Signals
Hopper level signals based on hopper status indicator system shall report
to a microprocessor through a coaxial cable system. Each hopper shall have
two indicators, one for full and one for empty. A flashing light shall
indicate a wall buildup. Loss of power for any period of time shall not
require a recalibration. Enclosure for microprocessor shall be [NEMA 4]
[12] and shall be located in [_____]. Each group of detector units for a
single fabric filter baghouse shall be incorporated into the unit alarm
system for its respective baghouse so that a high level in any hopper shall
indicate as part of the unit alarm system.
2.12.11
Transmitters
Each transmitter shall be selected and adjusted for the service and
operating conditions required and shall be designed to operate at the
maximum condition expected. Transmitters shall be electronic, two-wire
type with 4-20 mA current signal output powered by 24-volt DC source unless
specified otherwise. Enclosures shall have NEMA 4 rating as a minimum.
Devices shall be designed to operate continuously under the ambient
conditions specified. Furnish condensing pots for flow and level
transmitters when required by the conditions of the measured fluid. Furnish
seal pots or diaphragm seals where required for the fluid being measured.
Furnish transmitter mounting brackets suitable for either surface or piping
mounting. Furnish any power supply, transformer, rectifier, or other
device required to interface the equipment with the system. Magnetic
flowmeter transmitters (signal converters) shall be compatible with the
primary elements. Ultrasonic level transmitters shall be protected from
process fluid corrosion by resistant coating or material. Temperature
compensation shall be within accuracy requirements. Integral output
indication shall be graduated in engineering units. Accuracy shall be at
least plus or minus 2 percent of measured range. Provide with coaxial
cable from each probe to each transmitter. Provide with recommended
installation hardware for flange mounting. Transmitter shall use doppler
effect to filter out moving fill material during measurement.
2.12.12
Limit Switches
Limit switches shall be provided with DPDT contacts. Limit switches shall
be provided with housing conforming to NEMA 4 requirements.
2.12.13
Gage Glasses
Glass shall be 20 mm 3/4 inch borosilicate type class red line tubular.
Length shall be a maximum of 915 mm 36 inches per section. Use multiple
overlapping sections for more than 915 mm 36 inches length allowing one
inch visible overlap between sections. Gage valves shall be offset with 20
mm 3/4 inch union tank connection. Provide four guard rods with holders.
Drain valve shall be 15 mm 1/2 inch globe-type needle valve.
2.12.14
Solenoid Valves
Valve body shall be brass of 316 stainless-steel as required by the
SECTION 15864N
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