South Park Swivel Coupling

The South Park SDF-33 Series Swivel Couplings provide a secure transition between female NPT pipe threads and NST fire service threads. Constructed from durable brass with a chrome-plated finish, these rocker lug swivel couplings are designed to simplify hose and plumbing connections while allowing easy rotation during installation and operation. Available in configurations with or without an internal screen, the SDF-33 Series offers flexibility for a variety of fire apparatus, drafting, pump, and water transfer applications.

Features

• Brass Construction: Durable brass body provides long service life in demanding environments.
• Chrome-Plated Finish: Corrosion-resistant finish helps maintain appearance and durability.
• Swivel Design: Allows rotation of the coupling to simplify installation and reduce hose twist.
• Female NPT x NST Connections: Adapts pipe thread connections to fire service hose threads.
• Rocker Lug Configuration: Provides secure grip for tightening and removal.
• Multiple Size Configurations: Available in several NPT and NST size combinations.
• Screened and Non-Screened Models: Allows users to select the configuration best suited to their application.

What Is It?

The SDF-33 Series is a swivel coupling designed to connect NPT plumbing connections to NST fire hose thread connections. The swivel feature allows the coupling to rotate independently, making installation easier while reducing stress on connected components.

How Is It Used?

These couplings are commonly installed on pumps, tanks, plumbing systems, drafting equipment, and other water delivery systems where a transition between NPT and NST connections is required. The swivel action allows connections to be made without twisting attached hoses or piping.

Who Uses It?

• Fire Departments
• Apparatus Manufacturers
• Municipal Water Utilities
• Industrial Fire Brigades
• Maintenance and Fleet Service Personnel
• Water Transfer and Pump Operations

Difference Between the SDF-33 and SDF-33S

The primary difference between the two series is the presence of an internal screen.

• SDF-33 (Without Screen)
  • The SDF-33 features an open waterway with no internal screen. This design allows unrestricted water flow and is often preferred when the water source is already filtered or debris is not a concern.
• Benefits:
  • Maximum flow path
  • No screen maintenance
  • Ideal for clean water systems
  • Reduced possibility of screen blockage
• SDF-33S (With Screen)
  • The SDF-33S includes an internal screen designed to help prevent debris from entering downstream equipment and hose lines. The screen can provide an added level of protection when drawing from water sources where debris may be present.
• Benefits:
  • Helps reduce debris entry into pumps and hose lines
  • Provides additional protection for downstream equipment
  • Useful in drafting and water supply operations where debris may be encountered

Which One Should You Choose?

Choose the SDF-33 when maximum water flow and minimal maintenance are desired.

Choose the SDF-33S when protecting pumps, appliances, or hose lines from debris is a priority.

What Is It Used With?

• Fire pumps
• Water tanks
• Drafting equipment
• Fire hose assemblies
• Fire apparatus plumbing
• Water transfer systems
• NST fire service connections
• NPT plumbing connections

Maintenance Information

Inspect swivel operation, threads, rocker lugs, and sealing surfaces regularly. For screened models, periodically inspect and clean the screen to ensure proper water flow and debris protection. Replace components showing signs of excessive wear or damage.