Pemilihan Steam Trap

873_Cons_Guide.
qxd 3/31/06 3:59 PM Page CG-12
The Controlled Disc Steam Trap

The controlled disc steam trap is a time-delayed device that operates Unique Heating Chamber
on the velocity principle. It contains only one moving part, the disc The unique heating chamber in Armstrong’s controlled disc traps
itself. Because it is very lightweight and compact, the CD trap meets surrounds the disc body and control chamber. A controlled bleed
the needs of many applications where space is limited. In addition from the chamber to the trap outlet controls the cycle rate. That
to the disc trap’s simplicity and small size, it also offers advantages means that the trap design—not ambient conditions—controls the
such as resistance to hydraulic shock, the complete discharge of cycle rate. Without this controlling feature, rain, snow and cold
all condensate when open and intermittent operation for a steady ambient conditions would upset the cycle rate of the trap.
purging action.
Operation of controlled disc traps depends on the changes in

Table CG-6. Typical Design Parameters for Controlled Disc Traps
pressures in the chamber where the disc operates. The Armstrong
CD trap will be open as long as cold condensate is flowing. When Body and Cap Materials Steel
steam or flash steam reaches the inlet orifice, velocity of flow Connections 3/8" thru 1"
increases, pulling the disc toward the seat. Increasing pressure in
the control chamber snaps the disc closed. The subsequent pressure Type Connections Screwed, Socketweld or Flanged
reduction, necessary for the trap to open, is controlled by the heating Operating Pressure (psig) 10 thru 600
chamber in the cap and a finite machined bleed groove in the disc.
Capacity (lbs/hr) To 2,850
Once the system is up to temperature, the bleed groove controls
the trap cycle rate.
Figure CG-13. Design and Operation of Controlled Disc Traps Condensate Steam Air Condensate and Steam Mixture
Heating Chamber Control

Control Chamber Chamber
Disc is held
Control Disc High Velocity Flow against two
Inlet Passage Seat concentric
faces of seat
Outlet Passages
1. On start-up, condensate and air entering the 2. Steam enters through the inlet passage and 3. The disc closes against two concentric faces
trap pass through the heating chamber, around flows under the control disc. The flow velocity across of the seat, closing off the inlet passage and also
the control chamber and through the inlet orifice. the face of the control disc increases, creating a trapping steam and condensate above the disc.
This flow lifts the disc off the inlet orifice, and the low pressure that pulls the disc toward the seat. There is a controlled bleeding of steam from the
condensate flows through to the outlet passages. control chamber; flashing condensate helps main-
tain the pressure in the control chamber. When the
pressure above the disc is reduced, the incoming
pressure lifts the disc off the seat. If condensate is
present, it will be discharged, and the cycle repeats.
The Bimetallic Steam Trap

Bimetallic steam traps have the ability to handle large start-up Table CG-7. Typical Design Parameters for Bimetallic Traps
loads. As the trap increases in temperature, its stacked nickel-chrome
bimetallic elements start to expand, allowing for tight shutoff as steam Body and Cap Materials Carbon Steel Stainless Steel
reaches the trap, thus preventing steam loss. In addition to its light Connection Sizes 1/2", 3/4", 1"
weight and compact size, it offers resistance to water hammer.
Titanium valve and seat on high-pressure bimetallic traps ensure Screwed, Screwed, NPT,
Type Connections Socketweld, BSPT, Socketweld,
extremely long service life in the harsh environment of superheated
Flanged Buttweld, Flanged
steam systems.
Operating psig 0 - 250 200 - 900
Cold Water Capacity lb/hr up to 11,000
Figure CG-14. Design and Operation of Bimetallic Steam Traps Condensate Steam Air Flashing Steam
1. On start-up, the trap is cold, so the elements 2. With increasing temperature of the condensate, 3. When set temperature is reached, the force
are flat and the valve is wide open, which results the bimetallic elements will start to expand and flex. of the elements is high enough to close the valve
in air and condensate being easily removed from completely against the system pressure working
the system by working pressure. on the valve.
17
Armstrong Steam and Condensate Group, 816 Maple St., Three Rivers, MI 49093 – USA Phone: (269) 273-1415 Fax: (269) 278-6555
www.armstrong-intl.com Next CG-12

Pemilihan Steam Trap

Uploaded by

Copyright:

Available Formats

Pemilihan Steam Trap

Uploaded by

Document Information

Original Description:

Original Title

Copyright

Available Formats

Share this document

Share or Embed Document

Sharing Options

Did you find this document useful?

Is this content inappropriate?

Copyright:

Available Formats

Pemilihan Steam Trap

Uploaded by

Copyright:

Available Formats

873_Cons_Guide.

qxd 3/31/06 3:59 PM Page CG-12

The Controlled Disc Steam Trap

Operation of controlled disc traps depends on the changes in

Heating Chamber Control

The Bimetallic Steam Trap

You might also like