Wright-Austin Gas Liquid Separators with Float Drain Traps

Cast Iron separators with integral drain trap

Cutaway of Wright-Austin ST SeparatorThe Type ST separator combines the functionality of a Type T separator with a Type 90-AC float drain trap into a compact, single body design. The single-body design simplifies installation.

ST separators (separator traps) are designed to remove entrained liquid and solids larger than 10 microns from compressed air and saturated steam with 99% efficiency.  Once the air or steam enters the separator, a strong vortex is formed and the resulting centrifugal force propels droplets and particles larger than 10 microns towards the circumference of the vessel.  The exit nozzle extends into the low velocity area of the vortex and thus only droplets finer than 10 microns exit the separator. 

The droplets and particles coalesce in the float drain trap chamber located at the bottom of the separator.  The hollow stainless steel ball rises as condensate accumulates and due to the linkage between the float and valve, the valve is lifted off the valve seat once the float rises enough.  The system pressure pushes condensate through the valve seat and its diameter determines the rate of drainage; once the float lowers sufficiently the valve is re-seated.  Thus there is always a condensate barrier between the compressed air or steam and drain port of the separator trap, ensuring zero loss of compressed air or steam during drainage.

Separated condensate is prevented from re-entrainment due to a vortex containment plate (VCP).  As the name implies, this plate prevents the continuation of the vortex and its centrifugal forces below the VCP.

Removal of the bottom flange releases the trap mechanism for inspection and repair. All drain trap components are made of rust-proof stainless steel and include a nonmagnetic 18-8 stainless steel valve and seat.

The ST design is only available in cast iron material and thus typically used for air and steam applications.  When pressures or process gas necessitates other materials a custom fabricated separator with cast steel or stainless steel trap will be required.  ST separators are not able to have a ASME Code Stamp or CRN, so if this is a requirement it is another reason to consider our custom fabricated products.

Cutaway of Wright-Austin 31LST Separator

The low profile version of the ST separator is based upon the 31L/L1 design; the primary difference besides its physical dimensions is the volume of condensate which can be removed.  The ST style has a capacity equivalent to 40% of its maximum rated flow capacity whereas the 31L-ST has a capacity only equivalent to 5% of its maximum rated flow capacity.  Our web based sizing tool enables you to easy compare the condensate removal capacities in both weight and volumetric flow for each separator design.

PFD links to Outline Drawings: 

 Wright-Austin Threaded ST Separator Outline DrawingWright-Austin Flanged ST Separator Outline Drawing

Wright-Austin Threaded 31LST Separator Outline DrawingWright-Austin Flanged 31LST Separator Outline Drawing

PDF links to specification sheet and parts list:

Wright-Austin ST Separator SpecificationsWright-Austin ST Separator Parts List

PDF link ST installation instructions:

Wright-Austin ST Separator Installation Instructions

Part Numbering charts for ST and 31LST Separators:

SIZE

CONNECTION

PART NUMBER

¾"

FNPT

0.75STBN

1"

1.STBN

1¼"

1.25STBN

1½"

1.5STBN

2"

2.STBN

125# FF ANSI FLANGED

2.STFN

2½"

FNPT

2.5STBN

3"

3.STBN

125# FF ANSI FLANGED

3.STFN

4"

4.STN

5"

5.STN

CONNECTION SIZE PART NUMBER
FNPT
250 PSI @ 450°F
1" 1.31LSTN
1¼" 1.2531LSTN
1½" 1.531LSTN
2" 2.31LSTN
2½" 2.531LSTN
3" 3.31LSTN
FF ANSI FLANGED
125 PSI @ 450°F
3.31LSTFN
4" 4.31LSTFN