Control Products DUA User Manual

66

845.778.5566 ● Fax: [phone] ●

www.nicholsonsteamtrap.com

The Nicholson Drain Orifice Trap is an
engineered, continuous flow device. The
controlling element in the Drain Orifice
Assembly is a flat S.S. plate, 1/4" thick. Drain
Orifices discharge air, condensate and all other
non-condensible gases with minimal live steam
loss. The fixed orifice size is calculated, for a
given application, to discharge the condensate
load at a maximum thermal efficiency.
Approximately 10-25% of discharging hot
condensate flashes to steam at the downstream
side of the orifice, at a constant pressure drop.
This flashing effect further restricts the flow of

saturated steam, In actual conditions, a minimum
percentage of steam, by weight, is discharged with
condensate, since the specific volume of steam is large
compared to that of the condensate. The velocity
through the orifice is highly turbulent. The initial cal­culated steam loss can be expected to remain relatively
constant over the expected 10+ years trap life. The major
factor for energy efficient performance is based on initial
orifice sizing for the application. Properly sized, thermal
efficiencies of 98%+ can be attained. The Drain Orifice
Trap is ideally suited for use on high pressure steam
(saturated or superheated) from 300 PSIG to 3000 PSIG
with minimum steam loss, zero maintenance and long
service life.

TYPE DUA

ORIFICE UNION

ASSEMBLY

Pressures To 3000 PSIG (207 barg)

Temperatures to 850°F (454°C)

Reliable Operation — High reliability labyrinth-type seal:

leak tight seal is maintained when subjected to
expansion or contraction due to temperature or pressure
changes in the line. Positive, leak-tight seal eliminates
loss of product.

Ease of Installation — No danger of damaging seats or

losing seal by overtorquing during installation. Requires
normal torque to obtain a leak-tight seal. Welding repairs
reduced; no need to replace union components welded
to pipe.

Low Cost Maintenance — Downtime, labor and material

costs drastically reduced. Service is required only when
the union is disassembled, then only a change of gaskets
is required to put it back in service. Eliminates the need
to replace the union housing.

Flexibility — Orifice easily replaced where a different

orifice size is required for a specific application. Orifice
can be redrilled to a larger size, if necessary, eliminating
need to replace the entire assembly. Infinite range of
orifice sizes available from a minimum 0.020" diameter.

M

ODELS

●

DUA–Orifice Union

●RUA–Orifice Kit includes 2 gaskets, orifice plate and

inlet screen.

●DUR–Gasket Kit includes 2 gaskets and inlet screen.

●SUG–Gasket Kit includes 10 gaskets.

APPLICA TIONS

●

Condensate Removal

●Pressure Reduction

●Ratio of Flow-mixing two or more fluids at

fixed ratio

●Fixed Flow-i.e. gland seal recirculation of

cooling water on pumps, compressors,
process analyzers, etc.

●Intermittent Drainage-i.e. air tools, air storage

tanks, cleaning fixtures, air vents, etc.

●Cryogenic Storage Venting

●Low Pressure Blanking

●Sampling of process fluids at a fixed flow rate

for use with Instrument Analyzers

O

PTION

●

SW - Socketweld

Canadian Registration # 0E0591.9

OPERA TION

845.778.5566 ● Fax: [phone] ●

www.nicholsonsteamtrap.com

67

Connections: 1/2" – 1" NPT

TYPE DUA

ORIFICE UNION

ASSEMBLY

SPECIFICATION

Orifice Union shall consist of 1/4" 304 stainless steel plate fixed
inside a gasketed union housing. Seal shall be provided by spiral
wound gaskets whose inlet shall be modified with a stainless
steel dome mesh strainer fixed across the inside diameter. Orifice
shall be sized for the application to a minimum of 0.020 inches.

MAXIMUM

OPERA TING CONDITIONS

PMO: Max. Operating Pressure see Chart
TMO: Max. Operating Temperature see Chart

MATERIALS OF CONSTRUCTION

Body: …………………………………Forged Carbon Steel
Inlet Gasket:Spiral-wound S.S./Graphite w/S.S. 60 mesh

dome strainer insert
Orifice Plate: …………………………304 S.S., 1/4" thick
Outlet Gasket: ………………Spiral-wound S.S./Graphite

S

IZING*

Consult Factory–required information:

Condensate Load ______
Inlet Pressure ______
Outlet Pressure ______
Elevation of return line over trap (if any) ______

* Specify orifice size when ordering.

DUA

Dimensions

Pipe Size

Inches Weight

NPT A B Lbs.*

1/2 2.42 1.8 1.2
3/4 2.73 2.20 1.8

1 2.94 2.57 2.6

*Average weight-actual weights
may vary slightly.

*Minimum recommended temperature is -20°F.

Temperature/Pressure Ratings

Temperature* Pressure (PSIG)

°F Carbon Steel

100 3000
200 2735
300 2655
400 2565
500 2425
600 2220
700 2155

A

B