tank for regeneration of the softener exchanger material. Each unit shall
be a fully automatic, downflow pressure type water softener. The assembly
shall be provided with the alarm and controls necessary to provide a
complete operable system. The softener tank shells shall be of electric
welded, heavy gauge, low carbon steel hot-dipped galvanized construction
and the brine-solution tank shall be of polyethylene construction. The
exchange material shall not require dosing or the adding of any chemical
mixture or solution, either to the water to be treated or the water used
for backwashing or regeneration, other than common salt (NaCl). The
brine-solution tank shall be provided with indicators for measuring the
correct volume of brine for regeneration and shall be of adequate size to
provide for necessary salt storage. A hydraulic ejector or motor-driven
all-bronze pump with valves, piping, and connections shall be provided for
delivering brine to the softeners. The softeners shall be designed for 100
psi working pressure, and shall be designed and constructed in accordance
with ASME BPVC SEC VIII D1. A display of the ASME seal on the softeners or
a certified test report from an approved independent testing laboratory
indicating conformance to the ASME Code shall be provided.
2.24.3
Automatic Operation and Controls
Operation shall be initiated automatically and regeneration of the unit
shall continue automatically. Operational power shall be from a 120 volt,
60 Hz, single-phase ac motor or self-contained hydraulic system.
Electrically operated units shall be provided with a 5 meter15 foot
electrical cord and plug cap matching the electrical receptacle provided
for service. Electrical control shall be designed to be operated manually
in the event of failure of the electrical equipment. The necessary
washing, brining, and rinsing operations shall be timed by suitable timing
device and carried out without manual attention or supervision other than
to keep the salt-storage tank filled. Following complete regeneration, the
softening run shall start automatically. Each function of softener
operation shall be controlled mechanically or electrically, or by both
methods in combination to assure the highest degree of efficiency; and the
controls shall be capable of convenient and accurate manual adjustment. An
interlocking system shall be provided that prevents the regeneration of
more than one unit at a time. The transfer of water and brine solution to
and from the water softener shall be accomplished by a single-unit
multiple-port valve or by a package-type valve nest for automatic operation.
2.24.3.1
Multiple-Port Valve
The multiple-port valve shall consist of an assembly of nonsticking,
nonleaking, water-lubricated valve ports that connect to the hard-water
inlet, soft-water outlet, backwash inlet and outlet, and brine inlet, all
enclosed in a single casing. The design shall permit the various steps of
operation service, backwash, brine flow, and rinse to be accomplished by
the rotation of a shaft that drives the mechanism causing the opening and
closing of ports in correct sequence. The design of the valve mechanism
shall be such that gradually increasing flows will be attained as ports are
opened and initial surges and sudden inrushes of water or brine solutions
are avoided. A dial pointer shall indicate each step of the operation.
2.24.3.2
Package-Type Valve Nest
The package-type valve nest shall consist of a pilot valve connected with
fittings as may be required to each one of a nest of valves hydraulically
or electrically operated. The nest of valves shall have connections to
hard-water inlet, soft-water outlet, backwash inlet and outlet, and brine
SECTION 15405A
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