PRINCIPLE OF OPERATION
The SkoFlo valve is a pressure
independent flow control valve used in
the petroleum industry to accurately inject
chemicals. The valve consists of a body, a
base plate that is bolted to the body, and a
flow rate adjustment handle.
The principle of operation of the Model
SF15000NMF SkoFlo valve is that it
internally maintains a constant differential
pressure across an adjustable Cv section,
thus resulting in a constant flow through
that Cv section. The piston/spring
assembly utilizes system pressure to
adjust the internal pin and seat Cv section,
which then sets a constant differential
pressure across the adjustable Cv section,
thus maintaining a constant flow. Flow
rate changes through the valve can only
be made by adjusting the rate adjustment
handle.
Fluid enters the valve inlet at pressure P
1
and flows into chamber 1. It then flows through the
adjustable Cv section into chamber 2 where the piston and springs are located. These springs
put a force against the piston based on how much the springs are deflected. The spring force
against the piston is set by the differential pressure between P
1
in chamber 3 and P
2
in chamber
2. This pressure balance establishes the pressure P
2
in chamber 2 at a fixed differential from P
1
.
Flow then exits the valve at pressure P
3
after passing through the seat. The flow through the
seat is held back by the pin that mates with the seat. As the pressure in chamber 2 changes,
either as a result of a change in P
1
or a change in P
3
, the pin moves in relation to the seat and
controls pressure P
2
. As soon as equilibrium flow through the valve is established, the flow rate
will remain constant even when pressures upstream and/or downstream of the valve change.
Rate
Adjustment
Handle
Adjustable
Cv Section
P
1
P
3
P
2
IN
OUT
CHAMBER 2
P
2
CHAMBER 3
P
1
CHAMBER 1
P
1
Springs
Pin
Seat
Piston
Valve
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Содержание SF15000NMFB
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