FIELD OF INVENTION
This invention relates to noise reduction equipment for high capacity boilers.
More particularly, this noise reduction equipment is used in safety valve outlet
vents and start up vents of super critical boilers, where the capacity, pressure
and temperature are higher than the normal boiler, and can be deployed
wherever high capacity, high temperature safety valves are used.
BACKGROUND OF INVENTION
Noise reduction equipment is a device used for attenuate the noise generated
during the opening of safety valves, start up vent. As per Occupational Safety &
Health Administration (OSHA) regulation, for instance, allows a maximum level of
115 decibels on the A weighted scale (dBA) for a noise exposure of a quarter of
hour each eight hours. When safety valve opens, high level noise is generated
around 140 dBA.
The frequency of noise generated is grouped with octave bands. The bands of
frequencies to be attenuated to protect environment. This noise reduction
equipment is developed for the inlet pressure of 2 kg/cm2g, the drip pan /
pressure reduction unit is used to obtain this inlet pressure.
OBJECTS OF THE INVENTION
It is therefore an object of the invention to propose a noise reduction equipment
for high capacity boilers which is capable of reducing both high and low
frequency noises.

Another object of the invention is to propose a noise reduction equipment which
is capable of reducing the noise for high capacity, high temperature and high
pressure steam in high capacity boiler.
SUMMARY OF INVENTION
This noise reduction equipment is absorptive and reactive type, which reduces
the both high and low frequency noises.
The inlet connection of the noise reduction equipment is Inserted type to
accommodate the thermal expansion of the vent pipe; also this arrangement
eliminates the need for two extra flanges to be used at the inlet thereby reducing
the overall weight of the system.
The diffuser is used to attenuate the low frequency noise. The Fibre glass wool is
used to absorb the high frequency noise. The acoustic fill (Fibre glass wool) is
wrapped with fibre glass cloth and wire mesh.
The outlet is modified by replacing the bend hood with umbrella hood, which
eliminates horizontal reaction force, effect of wind force and also reduces the
overall weight of the equipment.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
Figure - 1 shows a cross-sectional view of Noise reduction equipment according
to the invention with umbrella hood.
Figure - 2 shows a view of existing outlet with bend hood. This illustrates the
flow directions and the direction of reaction force (FR) at the existing
equipment outlet.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE
INVENTION
Fig.1 illustrates the noise reduction equipment of the invention. The equipment
comprising of inlet tube assembly (01), welded with inside of the bottom plate
(12). The exhaust pipe of safety valve is inserted into the inlet tube assembly
(01). The bottom plate (12) is connected with the outer shell (02). The diffuser
assembly (03) is fabricated at top of the bottom plate (12).
The diffuser assembly (03) reduces the low frequency noise. The support
assembly (04) is integrated with the outer shell (02). The perforated sheets (05)
are used in baffler assembly which comprises acoustic-fill of fibre glass wool
(07), firbre glass cloth and wire mesh (08) which attenuates high frequency
noise. Baffler support (06) are fabricated with outer shell (02) and used as
partition with diffuser assembly (03). The lifting lug assemblies (09) are
integrated with outer shell (02) when the bird screen assembly (10) is welded
with outer shell (02) at the top of the baffler assembly. The umbrella hood (11)
which is fabricated at the top, eliminates horizontal reaction force and effect of
wind force.

WE CLAIM
1. A noise reduction equipment for high capacity boilers comprising;
an inlet tube assembly (01) welded with inside of the bottom plate (12);
the exhaust pipe of safety valve inserted into the inlet tube assembly (01);
the bottom plate (12) connected with the outer cell (02);
characterized in that,
the diffuser assembly (03) fabricated at the top of the bottom plate (12)
reduces the low frequency noise wherein the perforated sheets used in
baffler assembly comprising acoustic-fill of fibre glass wool (07), fibre
glass cloth and wire mesh (08) for attenuating high frequency noise when
the umbrella hood (11) being fabricated at the top, eliminates horizontal
reaction force and effect of wind force.
2. A noise reduction equipment as claimed in claim-1, wherein baffler
supports (06) are fabricated with outer shell (02) and used as partition
with diffuser assembly (03).
3. A noise reduction equipment as claimed in claim 1 and 2, wherein the
lifting lug assemblies (09) are integrated with outer shell (02) when the
bird screen assembly (10) is welded with outer shell (02) at the top of the
baffler assembly.

The invention relates to noise reduction equipment used in high capacity boilers;
the exhaust pipe of safety valve is inserted into the inlet tube assembly (01), the
diffuser assembly (03), which reduces the low frequency noise. The baffler
assembly, which comprises acoustic-fill (fibre glass wool) (07), fibre glass cloth
and wire mesh (08), attenuates high frequency noise. The umbrella hood (11)
which is integrated at the top, this eliminates horizontal reaction force and effect
of wind force.