1/4" to 4" One way out (V) and One Way In (I) Non Slam (NS) for ARI Air Valves, Aquestia group
Function #1 One-way In
One-way in, the shaft and spring are above the disc. The disc of
the check valve is normally in the closed position, not allowing
air discharge. When the negative differential pressure across the
check valve is higher that the force of the spring, the check valve
opens, allowing air intake into the air valve
(Available in sizes 1/4", 3/8", 1½", 2", 3", 4")
Function #2 One-way Out
One-way out, the disc is on top, with the shaft and spring below.
The disc of the check valve is normally closed, and opens only
when the differential pressure across the check valve is higher
than the force of the spring, allowing air to discharge from the
valve. The check valve does not open for air intake.
(Available in sizes 1/4", 3/8", 1½", 2", 3", 4")
Function #3 Non-Slam (Three-stage Capacity Air Discharge)
1½" NS Component
Non-Slam, the disc (Fig. 1) has one permanent hole (orifice)
that is not adjustable. Air discharge capacity is controlled by the
discharge of air through the single orifice.
2", 3", 4" NS Component
Non-Slam, the disc (Fig. 2) has three small holes (orifices) that can
be closed or opened / or the disc (Fig.2) has three or more holes
that are permanently open.
Air discharge capacity is controlled by partially or fully opening
one or more of the three orifices (Fig. 1) or with all the holes
permanently open (Fig. 3) - reducing potential surge.
At water column separation, drainage, pipe burst, sudden closure
of the isolating valve, pump trip, etc., the check valve and air valve
open, allowing large volumes of air into the system. When the
water column returns, air is discharged through the small orifices
(one orifice - 1½" model) at a rate determined by the orifice
opening setting (set manually by the user). This way, air discharge
is controlled, greatly reducing the effects of slam.
