Type-21/21a True Union Ball Valve (1/2″ – 6″)
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Ball Valves

Type-21/21a True Union Ball Valve (1/2″ – 6″)

Type-21/21a ball valves are corrosion-resistant, plastic, manual true union quarter-turn valves designed to deliver dependable shutoff performance in demanding environments. Their hyperbolic flow characteristics help provide efficient flow when fully open, contributing to low pressure drop across the valve and reliable sealing when closed. Because these valves are primarily intended for on/off service, they typically offer limited throttling capability and relatively poor fine flow control compared with valves designed specifically for modulation.

They perform best in clean fluid service where suspended solids are minimal to nonexistent, helping reduce the risk of abrasion, buildup, or interference with the sealing surfaces. With that in mind, Type-21/21a ball valves are a practical choice for a wide range of general fluid handling applications where chemical compatibility and corrosion resistance are important considerations.

A key advantage of the true union design is simplified maintenance and installation flexibility. The valve body can be removed from the pipeline without disturbing the surrounding piping by loosening the two union nuts, allowing quick access for inspection or service. In addition, the valves can be disassembled so internal components can be cleaned, repaired, or replaced as needed, which can reduce downtime and extend service life.

For automation requirements, Type-21/21a ball valves can also be equipped with pneumatic or electric actuators, enabling remote operation, repeatable switching, and integration into control systems where manual operation is not ideal.

Document Finder Type-21/21a Ball Valves Resources

Resources:

Data Sheets

Dimensional Guides

Specifications

Ideal Applications Include:

Isolation valves, water treatment, water features, fountains, aquariums, landfills, swimming pools, power plants, mining, transportation, chemical processing

Certifications:

Specifications:

Sizes:

1/2″ – 4″

*6″ end connections available for 4″ valve bodies

PVC/EPDM/FKM Models NSF-61 Certified

CPVC/EPDM/FKM Models NSF-61 Certified

Models:

PVC & CPVC: Socket, Threaded, and Flanged (ANSI)

PP & PVDF: IPS and Metric (DIN) Socket, Threaded, Butt, and Flanged (ANSI)

Bodies:

PVC, CPVC, PP, and PVDF

Seats:

PTFE backed with EPDM or FKM

Seals:

EPDM or FKM or AFLAS

  • Pressure rated up to 230psi (PVC, CPVC, PVDF)
  • Double O-ring seals on stem for added protection
  • Full bore, sizes 1/2″ – 2″
  • Full vacuum rated, all sizes
  • Blocks in two directions, upstream and downstream, leaving full pressure on the opposite end of the valve
  • Integrally molded ISO mounting pad for both manual and actuated operations
  • Integrally molded base pad to mount valves securely or panel mounting
  • PTFE seats with elastomeric backing cushions ensure bubble tight shut-off and a low fixed torque, while at the same time compensating for wear
  • True union design for easier installation or repairs without expanding the pipe system
  • Built-in spanner wrench on the handle for valve disassembly and assembly
  • Two sets of end connectors (socket and threaded) included with all PVC and CPVC valves in sizes 1/2″– 2″
  • CPVC threaded end connectors on sizes 1/2″ – 1″ come with stainless steel reinforcing rings
  • New PTFE seat design – Facilitates easier field maintenance if required
  • Tapered O-ring groove – Helps to keep the end connector O-rings on the valve body during installation
  • Body flats – Flats have been added to either side of the valve body where a wrench can be applied to prevent the valve body from turning when the union nuts are tightened
  • 1/2″ – 2″ PVC and CPVC Type-21a design