Installation & Maintenance
of Forcemain
Air Relief Valves
Why do we need AIR VALVES?
Delay in pipeline filling
Reduction in discharge capacities
Risk of surge and water hammer
Possible pipeline collapse
Increased pump/running costs
Pipeline corrosion
Where Do We Need Air Valves?
Air Valves should by sized for
vacuum conditions. which result from pipeline rupture or
instantaneous pump stoppage
and from column separation.
Air Valves should be installed at the high points of the
line
High Points
Standard Practices
Air Valves should by sized for vacuum conditions which may
result from pipeline rupture or instantaneous pump stoppage
causing column separation.
Air Valves should be installed at the high points of the line
Air Valves should be installed where there are negative
breaks. (Decrease in upward slope or increase in downward slope)
Negative Breaks
Standard Practices
Air Valves should by sized for vacuum conditions which may
result from pipeline rupture or instantaneous pump stoppage
causing column separation.
Air Valves should be installed at the high points of the line
Air Valves should be installed where there are negative
breaks. (Decrease in upward slope or increase in downward slope)
Air Valves should be installed on long ascending lines at
about every 600m or 650 yards.
Ascending Lines
Standard Practices
Air Valves should by sized for vacuum conditions which may
result from pipeline rupture or instantaneous pump stoppage
causing column separation.
Air Valves should be installed at the high points of the line
Air Valves should be installed where there are negative
breaks. (Decrease in upward slope or increase in downward slope)
Air Valves should be installed on long ascending lines at about
every 600m or 650 yards.
Air Valves should be installed on long descending lines at about the
same 600m or 650 yards.
Descending Lines
Standard Practices
Air Valves should by sized for vacuum conditions which may
result from pipeline rupture or instantaneous pump stoppage
causing column separation.
Air Valves should be installed at the high points of the line
Air Valves should be installed where there are negative
breaks. (Decrease in upward slope or increase in downward slope)
Air Valves should be installed on long ascending lines at about
every 600m or 650 yards.
Air Valves should be installed on long descending lines at
about the same 600m or 650 yards.
At pump discharge - after a check valve.
Pump Discharge
Standard Practices
Air Valves should by sized for vacuum conditions which may
result from pipeline rupture or instantaneous pump stoppage
causing column separation.
Air Valves should be installed at the high points of the line
Air Valves should be installed where there are negative
breaks. (Decrease in upward slope or increase in downward slope)
Air Valves should be installed on long ascending lines at about
every 600m or 650 yards.
Air Valves should be installed on long descending lines at
about the same 600m or 650 yards.
At pump discharge - after a check valve.
Prior to a check valve on deep well pumps
Deep Well Pumps
Standard Practices
Air Valves should by sized for vacuum conditions which may
result from pipeline rupture or instantaneous pump stoppage
causing column separation.
Air Valves should be installed at the high points of the line
Air Valves should be installed where there are negative
breaks. (Decrease in upward slope or increase in downward slope)
Air Valves should be installed on long ascending lines at about
every 600m or 650 yards.
Air Valves should be installed on long descending lines at
about the same 600m or 650 yards.
At pump discharge - after a check valve.
Prior to a check valve on deep well pumps
At blank or dead ends
Where Does The Air Come From?
In Line at Start-Up Out of solution
Enters through equipment, pumps, fittings
Types of Air Valves
Conventional Design
Air Release
Air/Vacuum
Combination
Apco/ARI/ValMatic/Golden A./Crispin
Unconventional Design
Four Function Vent-Tech
Discussed Later
Air Release Valve
Releases air under pressure
Typically 3 inch or smaller
Limited ability to admit/exhaust air
Air/Vacuum Valve
Exhausts and admits large volumes of
air during pump start up, pipeline filling
and pipeline draining.
Will act as vacuum valve but will not
allow air to escape while pipeline is
under pressure.
Anti Slam device offered as add on
Combination Air/Vacuum Valve
Offers the functions of both the air
release and the air/vacuum valve
Either in a single or dual body design
they allow large amounts or air to escape
and enter and also allow air to escape
while line is under pressure.
Basic Designs
Air Release
Water
Air/Vacuum
Sewage
Combination
How does the Combination ARV work?
When air enters the valve, it is released through the large top outlet of the valve.
When fluid enters the valve, the fluid lifts the float and it seals the orifice button against the
stainless steel plug and presses the plug against a resilient seal. The plug contains a throughhole, which vents air when the force main is under pressure.
When a vacuum condition occurs in the pipeline, the float and plug drop and air enters
through the top of the valve.
Additional ports are provided for backwash and cleaning the valve.
Repair Parts List
4 Seat
5 Float
6 Gasket
8 Retaining Screw
9 Guide Bushing
10 Float Arm
11 Orifice Button
12 Pivot Pin
13 Retaining Ring
17 Float Retainer
18 Lock Nut
20 Guide Shaft
33 Clevis
34 Lock Washer
35 Guide Shaft Retainer
Maintenance [Per Manufacturer]
Wastewater valves should be scheduled for regular inspection
and backwash on a monthly basis. Val-Matic suggests a
more frequent backwash may be desirable to minimize
leakage.
Periodic inspection should be done to verify operation and
check for leaks. If the valve is leaking it is not seating and
should be backwashed.
Backwash Piping & Procedure
D
C
To properly backwash the valve a 1 clean
water supply of at least 30 psi is needed.
This supply should be connected to the top
of the valve with a rubber hose and quick
disconnect couplings.
Pipe valve B to drain prior to backwashing
Close inlet valve A
Open valve B
Connect water supply to C, open valve D
and supply water for 3 minutes. Close
valve D and B and slowly open valve A.
B
A
Air valves have been in use since the early 1900s.
Their basic design has not changed. Some refinements have been
made in the materials of construction. Conventional Air Valves have
served the industry well, but compared to other industries, they have not
kept up with technological advances.
The single most inherent shortcoming of the conventional air release valve
is the maintenance requirement, materials of construction and the cost
associated with the required maintenance.
In reality, air valves have become the joke of the industry. Their purpose
is misunderstood. Their maintenance requirements are unrealistic.
They are often installed and forgotten. Or they are only maintained
after an catastrophic break or pipeline malfunction.
Air valve failure is not entirely the maintenance departments fault.
Manufacturers have not invested enough time, money and research
into designing user friendly equipment.
In the real world, the manufacturers maintenance schedule is not
followed.
This is a shortcoming of the valve and the manufacturer....not the
maintenance department. Too often the only time an air valve is
visited or inspected is when there is visible trouble.
It is reasoned that the continuing expense of maintaining
the valves is far greater than the occasional need to replace
one.
Faulty or non working air valves result in:
Water Hammer
Increased Energy Costs
Faulty Seals and Pumps
Pump curve anomalies/discrepancies
Lower Volumes
Longer Pump Cycles
Possible Pipe Breaks
Wet and/or flooded valve chambers
So,........... what is the solution?
What else is there?
Two Types Categories of Air
Valves
Conventional Design
Air Release
Air/Vacuum
Combination
Apco/ARI/ValMatic/Golden A./Crispin
Unconventional Design
Four Function Vent-Tech
A New Design In Air Valve Technology.
Industry Recommendations:
Check Air Valves annually
More often for problematic valves
Look for leakage
ALMOST ANY VALVE WILL WORK WITH
ENOUGH
MAINTENANCE
