have calibration and alarm adjustments for compliance with Federal, State,
and local environmental regulations. The control or transmitter unit and
recorder shall have dust-tight metal enclosure. A purging air system shall
be provided to clean light source lens and light detector lens. The
control unit shall have adjustable alarm output contacts for various smoke
densities.
2.8.12
Sample Cooler
Sample cooler shall be a water cooled shell and tube or shell and coil type
heat exchanger with stainless steel tubes and cast-iron or steel shell
suitable for cooling the blowoff before sampling. The cooler shall be
connected to a header and valved so that the operator can obtain a sample
of properly cooled blowoff from any boiler as desired. The cooler shall be
properly supported and shall have a brass or bronze sampling cock with
lever or compression handle. A sampling glass container suitable for
handling the water temperature to be encountered and a hydrometer or
equivalent device suitable for measuring the concentration of solids in the
water and reading in parts per million shall be provided.
2.8.13
Oxygen Analyzer
If oxygen compensation controls are furnished, an oxygen analyzer shall be
provided to indicate, record, and control the percentage of net excess
oxygen in, and the average temperature of the flue gas leaving, the boiler.
The oxygen analyzer shall be of the direct probe type utilizing an in situ
zirconium sensing element. The element shall be inserted directly into the
process flue gas stream and shall directly contact the process gases. The
sensing element shall be contained within a protective shield mounted to
the ductwork by an adapter plate, furnished by the manufacturer. The
analyzer shall be equipped to allow daily automatic calibration check
without removing the analyzer from the process. That is, sample gases may
be injected directly on the sensing element while the analyzer is in the
process. The analyzer shall include any temperature compensation of
control required. The output signal range shall be 4 to 20 mA dc and shall
represent 0 to 10 percent as a linear function.
2.8.14
Continuous Blowdown
**************************************************************************
NOTE: Continuous blowdown equipment will be
provided if required by TM 5-810-1. If a firetube
boiler is specified, these paragraphs will be
deleted.
Blowdown system will be deleted if not required for
the project.
**************************************************************************
Package type blowdown system shall be rated as indicated. The system shall
automatically proportion blowdown to amount of makeup. The unit shall
include [the heat exchanger's flow control valve,] strainer, sample cooler
(if required), solenoid valve, and surge tank. [An extra-heavy blowdown
heat exchanger shall be provided. Tubes shall be of stainless steel. A
removable tube bundle shall be provided with U-tubes having bends twice the
thickness of the tubing. A rear baffle shall support all tubes at the
return bend.] A sample cooler shall be installed so that shell and tubing
can be removed without disturbing piping or mounting. Continuous blowdown
valve shall be the manual proportioning type fabricated of
SECTION 15559A
Page 55
Previous Page
