Product Overview

Armstrong CD-33 Series is a disc steam trap with the core design objective of controlling valve cycling rate. By reducing cycling frequency, this series offers significantly longer service life than conventional disc traps while minimizing maintenance time and substantially reducing steam costs.

The series includes four models: standard CD-33, standard with built-in screen CD-33S, low capacity CD-33L, and low capacity with built-in screen CD-33SL, meeting various flow application requirements. The unique three-port discharge design ensures stable disc operation, further extending valve service life. Precise capacity matching to application requirements avoids oversizing, which is a key factor in the long life of this series.

Key Advantages

Structural and Performance Advantages

• Three-Port Discharge Design: Provides stable disc operation, effectively extending trap service life.
• Controlled Cycling Reduces Wear: By controlling cycling rate, internal component wear is minimized, improving durability.
• Hardened Sealing Surfaces: Features integral hardened stainless steel seat and disc for enhanced wear resistance and extended service life.
• Freeze Protection: Designed with freeze-resistant features for low-temperature operating environments.
• Corrosion Resistance: Body uses electroless nickel-plated stainless steel material, effectively resisting corrosion for demanding applications.

Functional Configuration Advantages

• Flexible Optional Components: Choose from built-in Y-strainer, built-in blowdown valve, or weatherproof insulating cap as needed.
• Built-in Screen (S Series): CD-33S/CD-33SL models feature 30×30 mesh T-304 stainless steel screen to filter debris and protect the valve.
• Blowdown Options: Standard configuration includes blowdown plug, optional blowdown valve for convenient maintenance.
• Outdoor Adaptation: Optional weatherproof insulating cap reduces radiant heat loss in outdoor applications.

Applications

CD-33 Series traps are suited for different scenarios based on model:

Standard Capacity Applications (CD-33/CD-33S)

• Large steam main drainage
• Process equipment steam drainage
• Constant pressure HVAC heating equipment

Low Capacity Applications (CD-33L/CD-33SL)

• Steam main small flow drainage
• Steam tracing line drainage

Technical Specifications

Basic Specifications

Specification	Value
Valve Type	Stainless steel thermodynamic, integral seat design
Disc and Sealing Surface	Hardened
Surface Treatment	Electroless Nickel Plating
Max Allowable Pressure (Vessel Design)	915 psig @ 752°F (63 bar @ 400°C)
Max Working Pressure	600 psig @ 752°F (41 bar @ 400°C)
Min Working Pressure	3.5 psig (0.24 bar)
Max Back Pressure Ratio	80% of inlet pressure
Screen Specification (S Series)	30×30 mesh T-304 Stainless Steel

Capacity Parameters

CD-33 Series capacity varies with pressure. Key capacity data:

• CD-33/CD-33S (1" connection): Max capacity up to 2500 lb/hr (1134 kg/hr)
• CD-33L/CD-33SL: Suitable for low flow applications, capacity matched to small steam line requirements

Dimensions and Weight

Key Dimensions by Model (Unit: inch/mm)

Dimension	CD-33	CD-33S	CD-33L	CD-33SL
Pipe Connection Size	1/2" (15), 3/4" (20), 1" (25)	1/2" (15), 3/4" (20), 1" (25)	3/8" (10), 1/2" (15), 3/4" (20)	1/2" (15), 3/4" (20)
"A" Dimension	1-7/16" (37)	1-7/16" (37)	1-7/16" (36)	1-7/16" (36)
"B" Height	2-1/2" (63)	4-1/4" (108)	2-1/2" (63)	4-1/4" (108)
"C" Length	3-5/16" (84)	3-1/2" (89)	3-5/16" (84)	3-1/2" (89)
"D" Distance to Cap Top	1-3/4" (44)	2-1/4" (57)	1-3/4" (44)	1-3/4" (44)
"E" Weatherproof Cap Removal	-	3" (76)	-	3" (76)
"F" Blowdown Connection Size	-	1/4" NPT (6)	-	1/4" NPT (6)
"G" Blowdown Valve Removal	-	3-1/2" (89)	-	3-1/2" (89)
Weight (lb/kg)	1.4 (0.64)	2.2 (1.0)	1.41 (0.64)	2.2 (1.0)

Note: 1" connection CD-33 weighs 2.5 lb (1.1 kg), CD-33S weighs 3.25 lb (1.5 kg).