Val-Matic 1/2-3 Well Service Air Valve With Dual Port Throttling Device - Manual (Page 4)

VALVE CONSTRUCTION
AIR VALVE CONSTRUCTION
The Well Service Air Valve body and cover are
cast iron. All internal components are stainless
steel with the exception of the valve seat, which
is resilient. The float (5) and float guide (20) are
the only moving parts assuring long life with
minimal maintenance. The general details of
construction are illustrated in Figure 2. The
body (1) is threaded for connection to the
pipeline. The seat (4) is retained in the cast
cover (2). The seat (4) is retained by a baffle
(3).
Figure 2. 1/2”-3” Air/Vacuum Valve
ITEM DESCRIPTION MATERIAL
1
Body Cast Iron
2 Cover Cast Iron
3 Baffle* Ductile Iron
4 Seat* Buna-N
5 Float* Stainless Steel
6 Gasket* Non-Asbestos
7 Cover Bolt Alloy Steel
8 Retaining Screw* Stainless Steel
9 Guide Bushing* Stainless Steel
14 Pipe Plug Iron
20 Float Guide* Stainless Steel
40 Baffle Screen* Stainless Steel
*RECOMMENDED SPARE PART
Table 2. Well Service Air Valve Parts List
THROTTLING DEVICE CONSTRUCTION
The Throttling Device has an exhaust disc which
is typically adjusted between 5% and 30% open
to control the venting rate. The valve needs to
be set in the field and tuned to the operation of
the pump. The Throttling Device should be
opened just enough so that all of the air is
discharged before the check valve opens.
Opening the throttling device further will
increase the pressure surge in the pump
column.
The Throttling Device also allows air to reenter
the pump column when the pump is stopped to
prevent a vacuum. A vacuum can damage the
seals in the pump or cause pump damage if it is
restarted while the water is still dropping in the
well. To provide positive assurance against a
vacuum, a dual-port throttling device is needed
where the vacuum port is separate from the
exhaust port. If there is a common outlet, then
the vacuum flow will be greatly restricted
through the air discharge pipe.
Figure 3. Dual-Port Throttling Device
3