CONVENTIONAL HYDROPNEUMATIC SYSTEM WITH
AIR COMPRESSOR


During the last half century various methods of water supply distribution for
residential and industrial application have been evolved. The earliest was the gravity
feed with overhead tank which are still in use. The other system which was largely
used was the Hydropnuematic System in which pressure tanks with certain amount
of compressed air and water were used as autoclaves to store water under pressure
and the pumps and air compressors then automated so as to maintain pressure
within a minimum and maximum range.

This system enables water supply under pressure to the taps and flushing
connections in domestic and industrial establishments by means of automatic
pumping equipments. The total 24 hours anticipated consumption is stored in the
Master underground tank from where the Hydropnuematic Pumps take their supply
and pump into a cylindrical pressure vessel which contains certain portion of
compressed air and from this pressure
vessel the water is fed into the system mains
to be carried to the various outlets.

The conventional system comprises of Pumps of special design for the required duty,
air compressors of 1-2HP to keep the air vessel charged with correct ratio of air to
water and to make up the air which has dissolved. The entire equipment operates
automatically through a control console and the pumps start at low pressure and
stop automatically at high pressure throughout the day and night, depending on the
demand for water. This system ensures adequate water supply, provided water is
available in the suction storage tank and electric supply is available. No overhead
storage tank is
necessary and the costly fixtures of the overhead tank such as ball
cocks, stop cocks,feed downtake branches are not required. Valuable open terrace
space is available.

There is no wastage of water due to overflow from overhead tank due to non
working of ball cocks. Instead of downtake branches from overhead tank to feed,
baths, WC etc., vertical branches from pressure tank to feed, baths, WC etc. are
taken from the common main laid on ground level.

This system involves provision of the following:-
1. Master underground suction tank of sufficient capacity to meet the daily demand.
2. Pumps of special design depending on lay out conditions suitable for
Hydropnuematic Duty.
3. Steel fabricated pressure vessel with manholes, water level gauge, pressure
gauge and automatic controls.
4. Vertical air cooled air compressors.
5. Electric control panel with relays, switches etc.

                                 OPERATION OF PUMPING INSTALLATION
Pumps are electrically operated by switching on the supply. The pumps start and
stop automatically by control switches and relays provided at the required
differential pressure range of the pressure vessel. As soon as the lead pump starts,
water is pumped into the pressure tank. The air in the vessel is compressed and the
water level in the vessel rises. When the volume of air is reduced, air compressor
starts automatically and feeds air into the vessel so that pressure is built-up. Equilibrium is established by equal volume of air and water; thus in the cylindrical
vessel air and water is at the same pressure and supply through delivery main
starts. As soon as the demand of water increases beyond the pumping capacity of
the lead pump, pressure falls beyond minimum pressure and the supplementary pump
starts automatically. As demand falls, the supplementary pump stops and thereafter
the lead pump stops. The supply can be cut off by closing the isolating valve
provided on the delivery main from the pressure vessel.

 

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