the working pressure of the boiler(s). Tank shall be equipped with a
tangential blowdown inlet located so as to impinge on a carbon steel wear
plate extending at least 180 degrees around the interior circumference of
the tank from the point of inlet. Tank shall be equipped with an internal
overflow, vent, drain, safety relief valve, and gage glass with try cocks,
blowdown cock, and guard. Tank interior shall be protected by an epoxy
coating system suitable for continuous water immersion and operation at a
minimum temperature of [121] [149] degrees C [250] [300] degrees F. The
tank [shall be fitted [with renewable magnesium anodes] [with cathodic
protection equipment] to minimize galvanic corrosion of the exterior.]
[shall be constructed of Class A reinforced concrete and shall be fitted
with a bolted steel manhole frame and cover. Install blowoff pipe, vent
pipe, and drain pipe in pipe sleeves built into concrete. Fill the space
between the pipe and sleeves and calk with lead wool or equivalent to make
a watertight seal. Tank shall be divided into two sections by means of a
baffle to form a sediment chamber.] Size and locate blowoff tank shall be
size and located as shown.
2.3.2
Sample Cooler
Provide a water-cooled, shell-and-tube, or shell-and-coil type heat
exchanger designed for cooling sample of boiler water prior to chemical
testing. Furnish the sample cooler as a component of the packaged
continuous blowdown system when such a system is being furnished. The
cooler shall consist of a cast iron or steel shell with copper coil or
copper alloy tubes and shall be equipped with a brass or bronze sampling
cock. [The cooler shall be connected to a header and so valved that a
sample can be withdrawn from any boiler as desired.] [Furnish a
concentrometer kit containing necessary glassware, reagents, and
instructions for determining boiler water concentrations.]
2.3.3
Continuous Blowdown System
**************************************************************************
NOTE: Specify continuous blowdown only where makeup
water ratio is in excess of 20 percent of the boiler
output or where the total dissolved solids of this
makeup water are in excess of 500 parts per million.
**************************************************************************
**************************************************************************
NOTE: Include last sentence if a console type unit
is indicated.
**************************************************************************
Provide a complete packaged unit of the [automatic-proportioning]
[manual-apportioning] type wherein the amount of blowdown from the [boiler]
[plant] is automatically proportioned to the amount of make-up feedwater
[and the total amount of blowdown from the plant is manually apportioned
between boilers according to their steaming rate]. The system shall
include either an automatic-proportioning valve and a heat exchanger or a
concentric tube automatic proportioning control which shall be provided
with a separate heat exchanger when necessary to meet the performance
requirements indicated or specified herein. The system shall be designed
for not less than boiler design pressure and shall be capable of heating
the feedwater from [_____] degrees C degrees F to [_____] degrees C degrees
F at the flow rates indicated. Heat exchanger shall consist of a steel
shell and heads with Type 304 stainless steel tubes arranged in a removable
U-bend bundle. Construct and test shell in accordance with ASME BPVC SEC
SECTION 15516N
Page 18
Previous Page
