HV SERIES Vent Silencers
UNIVERSAL
HV SERIES
Vent Silencers
HIGH-PERFORMANCE SILENCERS FOR VENTS AND BLOWDOWNS
Rugged Silencers
Reliable Services
Our HV vent silencers effectively silence high-velocity air,
Our extensive in-house engineering, manufacturing, and
steam, or gas vents and blowdowns to atmosphere where
testing facilities ensure optimized process, mechanical,
sonic or critical conditions exist in the valve. Typical
and acoustic performance for your application.
applications include:
Steam boiler relief valves
Superheater header relief valves
Boiler startup and purge
Annular Ring
High-pressure air vents
Natural gas blowdowns
Acousti-Tube
Switch valves
Compressor blowoffs
Autoclaves
HIGH-EFFICIENCY
Steam ejectors
ACOUSTIC PACK
Design Advantages
DESIGNED
Choice of overall attenuation, ranging from 15 dBA
FOR OPTIMUM
SPACE
to 60 dBA.
CONSIDERATIONS
Unique design options, combined with the latest
manufacturing techniques, ensure optimum
ALL-WELDED
performance and long life even under demanding
STEEL OUTER
SHELL
conditions.
Standard Features
PACK RETENTION
WITH PRE-
Welded heavy-duty steel construction.
COMPRESSION
Inlet plenum covered with outer acoustic wrap and
heavy-gauge shell.
LOWER CHAMBER
INSULATION
Highly absorptive fiberglass acoustic fill and heavy-
(except HV5, HV10)
gauge perforated face sheets.
Inlet nozzle and diffuser with flange drilled to 150#
INLET
ANSI standards.
DIFFUSER,
Lifting lugs and bottom drain.
DEPENDING ON
APPLICATION
Painted exterior.
Vertical or horizontal installation.
Optional Features
High-temperature acoustic fill.
Special materials, for example, stainless steel, Monel
The concentric annular ring design (left) and the wrapped
Acousti-Tube vent silencer design (right) offer a choice of
Hastelloy.
silencer profile and configuration to meet site-specific
Inspection openings.
requirements.
Mounting brackets or other special supports.
P
Outlet head and nozzle.
r
oduc
Restrictive diffuser built to ASME Section VIII,
Division I, to maintain back pressure or control
t C
blowdown time.
a
talog 243-C
Elbow, tailpipe, or weatherhood.
Special paint.
Side inlet.
P R O D U C T
D E S C R I P T I O N
HV SERIES
Vent and Blowdown Silencers
he HV Series comes with an inlet diffuser or
Easy To Specify and Order
orifice plate that is a critical element to the
acoustic and mechanical performance of the
Vent and blowdown silencers are seldom a simple
Tsilencer.Both the inlet nozzle and the diffuser/ catalog selection.Usually,the purchaser provides detailed
orifice plate are designed and constructed to
specifications and a system description that allows a
withstand the thermal and impact stresses produced
proposal for a silencer to be prepared and submitted
in high-pressure, high-temperature, continuous or
for review.
intermittent vent and blowdown service.
When you work with Universal Silencer, you can simply
In vent applications, critical flow will occur for most gases
send the manufacturer’s valve data sheet for your vent,
at valve upstream pressures greater than twice the outlet
and our experienced sales engineering staff can
pressure. Vent and blowdown noise levels increase with
recommend a silencer best suited for your application.
increased pressure drop and are also affected by valve
aerodynamic recovery characteristics. Large valve, low-
Application Analysis
pressure vents will produce relatively broadband low-
frequency noise, while high-pressure vents with small
We use the following design information from the valve
valves will produce high-frequency noise.
data sheet for system analysis and silencer selection:
Sub-sonic (or non-critical flow) low-pressure vent and
1.
Type of gas
2.
Molecular weight or specific gravity
blowdown applications do not require, nor in most
3.
Ratio of specific heats
cases does the valve have pressure drop available to
4.
Flow rate (lb/hr, ACFM or SCFM)
permit, the use of an inlet diffuser. Contact Universal
5.
Pressure and temperature upstream of valve and silencer
Silencer for silencer recommendations when a
6.
Maximum allowable pressure drop (psi) for valve and silencer
7.
Manufacturer’s name, and valve type and size
combination of both low pressure drop and acoustic
8.
Unsilenced noise levels from valve (if available)
requirements must be met.
9.
Silenced noise level (required at desired distance from source)
10.
Silencer inlet size and pressure rating
The HV Series is offered in six standard acoustic ratings,
11.
Inlet orientation, axial or side
12.
Silencer orientation, vertical or horizontal
as shown in Table 1. The HV05 is offered for applications
13.
Piping arrangement, including schematic if available
where only minimum noise reduction is required, while
14.
Other required options
the HV30 is offered for applications where maximum
silencing is required. Acoustic ratings are offered in sizes
Our form 88-0063 is available if you want to specify this
that cover a wide range of gas flow.
and other information in a standard format. Using your
information, we prepare computer analyses, such as
HV20 and HV30 acoustic ratings are offered for standard
those shown in Figure 1, and a comprehensive technical
pipe diameters from 2 to 112 inches. All other acoustic
proposal and price quotation. Silencer selection is based
ratings are offered for standard pipe diameters of 12 to
upon optimization of flow velocity, required acoustical
112 inches.
performance, and pressure drop. We are skilled in the
application of process engineering principles that are
needed to meet your performance requirements suc-
TABLE 1. Silencer ratings by grade classification
cessfully. A key element of a successful vent application
is proper assignment of pressure drop in the piping,
AVERAGE DYNAMIC
MODEL
CLASSIFICATION
INSERTION LOSS (dBA)
valve, and vent silencer. Valve performance and life can
be considerably extended by appropriate distribution
HV05
Industrial
15-20
of pressure drop in the piping system, valve, and vent
HV10
Commercial
20-30
silencer. In many instances it is possible to reduce the
HV15
Suburban
30-40
pressure drop across the valve body to less than critical.
HV20
Residential
40-50
This results in reduced valve actuator open/close force
HV25
Hospital
50-60
requirements. Reduced valve wear caused by cavitation
damage and reduced through-valve-body noise are
HV30
Critical
60-70
added benefits of this approach.
P R O D U C T
D E S C R I P T I O N
UNIVERSAL SILENCER
A F L E E T G U A R D / N E L S O N C O M PA N Y
P. O. Box 411, Stoughton, Wisconsin 53589
608-873-4272
Fax 608-873-4298
Silencer Acoustic Application
Peak Frequency
Example Valve Data
Octave Band Data from Noise Sources
Comparison of Two Methods
Total Volume Upstream and Downstream
for Calculating Noise Levels
from the Valve
FIGURE 1. Sample printouts of Universal’s vent application analyses.
We can verify the valve flow and pressure drop
orifice plate to stage the system pressure drop. For
characteristics from your valve manufacturer’s data sheet.
conservatism, vent silencers with restrictive diffusers are
We offer complete application engineering service,
designed with pressure ratings that match the PSV inlet
including determination of blowdown time; bottled
pressure rating. Also, you should assure yourself by
volume calculations; and complete valve, pipe treatment,
reviewing the valve manufacturer’s data sheet that the
and vent discharge acoustic performance predictions.
control valve will not malfunction from the rated back
pressure of the restrictive diffuser you specified.
Application Notes
The following cautionary statement pertains to applications
Note that pipe size immediately downstream from
in pure oxygen service: Customers are encouraged to contact
a valve affects the octave band distribution of the noise
the Compressed Gas Association (CGA) for more standards
spectrum. Universal Silencer has developed proprietary
related to preparation and cleaning for this type of service.
methods to predict this distribution so that we can select
the appropriate balance of reactive and absorptive
Construction Features
elements in the vent silencer design.
These silencers are welded heavy-duty fabrications. All
The annular vent silencers are assembled with structural
materials are free from rust, weld splatter, mill scale, and
members that provide for thermal expansion in high-
other contaminants. The inlet nozzle and diffuser are
temperature applications. The acoustic fill is long fiber,
constructed of steel and are welded. The diffuser provides
non-combustible, inert, vermin- and moisture-resistant
controlled pressure expansion to atmosphere and provides
fiberglass of at least four-pound-per-cubic-foot density,
uniform flow distribution through the acoustic section of
and is protected by both fiberglass cloth and a perforated
the silencer.
metal face sheet. The silencer is packed with a minimum
of 10% compression fill, and pack retaining rings are
The lined inlet plenum (expansion chamber) of the silencer
provided to minimize voids and settling of the fill.
is provided with a double shell separated by a layer of
acoustic insulation and sound-deadening material. The
The silencer will be designed so that the inlet flange and
inner shell is solid to prevent shell-radiated noise and
diffuser are matched to the discharge rating of the valve.
migration of the acoustic fill. The transmission loss across
We can work with you to obtain a more cost-effective
the plenum and bottom head is comparable to the silencer
valve and piping system by using a restrictive diffuser or
attenuation.
UNIVERSAL
HV SERIES
Vent and
Blowdown Silencers
Contact us for more
information about
our complete line of
industrial silencers
and air filter/filter
silencers:
Our corporate headquarters are located in Stoughton,
Vent silencer specification sheet, form 88-0063
Wisconsin, just southeast of Madison, the state capital. This
Air filters and filter silencers, catalog 241-A
new building houses administration, sales, and engineering
Cartridge air filters and filter silencers, catalog 242-B
departments. Manufacturing facilities are in Muscoda, 75
CB compact blower silencers, catalog 255-A
miles west of Stoughton, and Montello, 70 miles north.
CBF/CBFI compact blower filter-silencers, catalog 261-A
Reciprocating engines, catalog 246-A
Rotary positive blowers, catalog 244-D
Axial fans, catalog 249-D
Compressors, information provided by application
Vacuum pumps, catalog 222-B
Industrial fans, catalog 249-A
Steam ejectors, pressure reduction valves, and
Our products have been used to protect,
other special applications
quiet, and optimize the performance of
Gas turbines, catalog B-249-A
industrial equipment for 50 years.
Acousti-Tube
Silencers, catalog 260
We maintain a fully equipped facility for
Acousti-Tube
Silencer Series,
testing filters and silencers under actual
technical bulletin 94-1315
operating conditions. We are an ISO 9001
Uni-Pulse
inlet filter
registered firm and ASME Code certified.
systems, catalog 250
Preserving
a quiet
environment.
P. O. Box 411, Stoughton, Wisconsin 53589
608-873-4272
Fax 608-873-4298
info@universalAET.com
www.universalAET.com
Copyright 2010 Universal LLC. All rights reserved. Acousti-Tube and Uni-Pulse are trademarks of Universal
Specifications subject to change. 243-C-6/98
