Series-1221-1223-1224Configuration

Supported Applications

The Dwyer Series 1221, 1223, and 1224 are flanged chamber external mount liquid level switches designed for heavy-duty industrial environments. These units operate via a magnetic plunger mechanism attached to a removable stainless steel float within the chamber. The series is engineered for applications requiring operation at specific gravities as low as 0.40, making them suitable for oil and chemical processing.

Documented application contexts include:

• Oil refineries
• Chemical plants
• Power generating stations
• Other industrial environments requiring high-pressure level control

Operating Conditions & Performance

The series is rated for process pressures up to 1000 psig (69 bar) at 100°F (38°C), with a derated pressure of 850 psig (59 bar) at temperatures reaching 475°F (246°C). The minimum specific gravity supported is 0.40. Ambient operating temperature limits are specified up to 212°F (100°C).

Performance characteristics include a repeatability of ±1/4" (6.4 mm) and switch level changes that vary by specific gravity, with the "A*" dimension noted as not adjustable in two-stage configurations.

Pressure Ratings by Model

• Type 1221: 1000 psi at 100°F; 850 psi at 475°F Max. (Carbon steel body, side/bottom process connections).
• Type 1223: Available with 1" flanges in 150#, 300#, and 600# classes for side/bottom connections.
• Type 1224: Available with 1" flanges in 150#, 300#, and 600# classes for side/side connections.

Configuration Options

The series offers extensive configuration options across enclosures, circuit arrangements, materials of construction, and process connections to meet specific installation requirements.

Enclosure Ratings & Materials

• G (General Purpose): NEMA-1; painted steel and aluminum.
• WT (Weather Proof): NEMA-3R, 4, 4X; painted steel, aluminum, neoprene. Recommended for high humidity or outdoor service with H2 option.
• E (Explosion-proof): NEMA-7, 9, Class I Groups B, C, D, Class II Groups E, F, G (CSA approved Groups C, D, E, F, G only); aluminum construction. Includes breather and drain with H2 option.
• EV (Explosion-proof Vapor-proof): NEMA-7, 9, Class I Groups B, C, D, Class II Groups E, F, G; aluminum and neoprene.

Circuit Configurations & Outputs

The series supports single-stage or two-stage operation with the following contact types:

• Mercury Contacts (48XX): SPST, SPDT, DP-ST, and DP-DT configurations. Ratings include 10A at AC 120V/DC 125V for single-stage.
• Snap-Action Contacts (78XX): Hermetically sealed or standard snap switches in SPDT and DPDT arrangements. Includes high capacity DC options (98XX) requiring heat fins if process temperature exceeds 350°F (177°C).

Process Connections & Materials

• Standard 1" NPT hubs or optional flanged connections (150#, 300#, 600#). A 1" socket weld hub is available as an option.
• Wetted Materials: Carbon steel chamber with trim options including 303SS, 304SS, 316SS, and 430SS. The float is constructed of stainless steel.

Key Product Differences

The primary distinctions between models in this series relate to the chamber construction and process connection orientation:

• Type 1221: Features a flanged carbon steel chamber with side/bottom process connections via 1" NPT hubs. Rated for pressures up to 1000 psig.
• Type 1223: Designed with flanged process connections on the side and bottom, available in various pressure classes (150#, 300#, 600#).
• Type 1224: Similar to Type 1223 but configured for side/side flanged process connections.

All models share the same minimum specific gravity of 0.40 and utilize removable stainless steel floats for inspection and maintenance. Electrical ratings vary by circuit code, with special order options available for 440V service (identified by changing the first digit in the ordering code).