Type-21/21a True Union Ball Valve
The Type-21/21a is a thermoplastic true union ball valve for corrosion-resistant on/off service. Valve bodies are available in PVC, CPVC, PP, and PVDF. Sizes range from 1/2 in. to 4 in. They are rated to 230 psi. They also support full vacuum service. All sizes provide bidirectional shutoff. Full bore 1/2″ through 2″.
As a quarter-turn isolation valve, it is designed to be either fully open or fully closed. It is not intended for flow regulation. It performs best in clean fluid service with minimal or no suspended solids. For proportional control, see the Type-21a SST Flow Control Ball Valve or a thermoplastic diaphragm valve.
A true union valve body can be removed from the pipeline by loosening two union nuts. You can remove the valve without disturbing the surrounding piping. It also fully disassembles, so seats, seals, and the ball can be serviced in the field rather than replacing the valve.
An ISO mounting pad is molded into the body, so the same valve accepts manual, pneumatic, or electric actuation.
Ideal Applications Include:
Isolation valves, water treatment, water features, fountains, aquariums, landfills, swimming pools, power plants, mining, transportation, chemical processing.
Specifications:
Sizes: 1/2″ – 4″ (6″ end connections available for 4″ valve bodies)
Pressure Rating: Up to 230 psi (PVC, CPVC, PVDF); full vacuum rated, all sizes
Flow: Full bore, 1/2″ – 2″; bidirectional shutoff
Body Materials: PVC, CPVC, PP, and PVDF
Seal Materials: EPDM, FKM, or AFLAS
Body Type: True Union
Seats: PTFE backed with EPDM or FKM
Models: PVC & CPVC: Socket, Threaded, and Flanged (ANSI). PP & PVDF: IPS and Metric (DIN) Socket, Threaded, Butt, and Flanged (ANSI)
Maintenance and Installation
A built-in spanner wrench is integrated into the handle. Molded flat faces on both sides of the body prevent twisting. This helps while union nuts are tightened. In addition, a tapered O-ring channel retains the end-connector O-rings securely in position throughout installation. PVC and CPVC valves, sized 1/2 in. to 2 in., include two end-connection options. The options are socket-weld or threaded. For CPVC threaded ends from 1/2 in. to 1 in., stainless-steel reinforcing rings are included.
Resources:
Certifications:
PVC/EPDM/FKM Models NSF-61 Certified
CPVC/EPDM/FKM Models NSF-61 Certified
Frequently Asked Questions
Can a Type-21 ball valve throttle flow?
The standard Type-21/21a is an on/off isolation valve. Partial opening gives poor flow control and uneven seat wear. For modulating service, Asahi/America offers the Type-21a SST Flow Control Ball Valve. It is available in sizes from 1/2″ to 2″. It uses a precision-machined ball and Seat Support Technology. This design delivers modified equal percentage flow across the full travel range.
What sizes does the Type-21/21a come in?
The Type-21/21a is available in valve body sizes 1/2″ through 4″. End connections in 6″ are available for 4″ valve bodies.
Is the Type-21 NSF-61 certified?
Yes, for specific material combinations. PVC and CPVC Type-21/21a valves with EPDM or FKM seals are NSF-61 certified.
What end connections are available on the Type-21/21a?
PVC and CPVC are available in socket, threaded, and ANSI flanged. PP and PVDF are available in IPS and metric (DIN) socket, threaded, butt fusion, and ANSI flanged.
Can a Type-21 ball valve be actuated?
Yes. An ISO mounting pad is molded into the Type-21/21a body. It accepts Asahi/America pneumatic and electric actuators directly.