Master Flo Choke
Valve Design
Flow Trim (External Sliding Sleeve and Internal Cage):
The choke valve system is based on a fixed
radially ported internal nozzle (flow nozzle) with an external sliding sleeve
(flow ring). The sleeve overlaps the nozzle ports to vary the flow.
Shutoff is accomplished by an independent seating
area upstream and remote from the throttling area. The choke incorporates a dead
band area to isolate the seating from the flow area. This isolates the seat from
the throttling surface.
| Wear Performance:
The external sleeve choke configuration has proven to
provide superior wear control over other choke trim styles.
The Master Flo choke controls high velocity flow jets
during throttling by directing the flow upwards into the flow ring
thereby containing the erosive energy within the flow trim. This
phenomenon is due to the external flow ring internal nozzle design. This
system is unique in protecting the valve body from high velocity fluid
impingement.
The potential wear is contained to the replaceable
flow trim components, and this in turn reduces the need for an outlet
blast wear sleeve as commonly seen with other trim configurations.
|
 |
Flow Control:
The staged ports within the flow nozzle are positioned
radially and orthogonal (one pair to the other) to prevent failure of flow
nozzle due to erosive linking of throttling ports and to provide precise flow
control.
The use of only two sets of ports in the flow nozzle provides
a long stem travel thus ensuring precise flow control throughout the range.
The staged port system provides control from a Cv below 0.1 up
to the valve's maximum. This high turn-down ratio and control eliminates the
necessity of multiple trim sizes.
Micrometer Indicator Head:
| Master Flo manually operated chokes are supplied with an
indicator head having a micrometer calibration scale* that provides
positive, repeatable valve position indication to 1/10 of a turn
increments. This, together with the inherent controllability of
the Master Flo trim design, results in excellent throttling control. |
 |
The indicator head has a square cross-section with a different calibration
scale on each face. This ensures that the valve position can be monitored
in the desired units including Cv, bean size, millimeters, or the micrometer
scale.
For P2 and larger chokes, the indicator head is supplied with a grease
fitting to allow lubrication of the upper stem area.
*Micrometer scale is standard on P5 and smaller, and optional on P6 and
larger.
Stem Lock Assembly:
Master Flo's optional stem lock for manually operated chokes allows the stem
to be locked in 10 positions per turn of the handwheel. This provides a
large number of fixed valve positions between the closed and full open position.
| Valve Model |
|
Locking Positions |
|
P2
P25
P3
P35
P4
|
|
110
120
170
160
200 |
Seat Leakage:
Master Flo choke valves attain Class V or, optionally, Class
VI shutoff per ANSI B16.104 1976 (FCI 70-2). Seating integrity is
maintained throughout the service life of the flow trim.
Flow Trim Construction/Retention:
| Flow trim components are available in
solid 17-4 PH stainless steel, or in Stellite, or Tungsten Carbide held
in stainless steel carriers with interference fits. No epoxies,
brazing, or threaded fasteners are used to retain components in their
carriers.
The flow nozzle and seat are retained in the valve
body by use of a retaining sleeve that is compressed against the seat by
the valve bonnet. The retaining sleeve also protects the valve
body cavity against erosion. No special tooling is required for
maintenance or service.
|
|
Master Flo Sizing/Flow Test Data:
The choke sizing data is based on ISA S75.01 and verified by
actual flow tests conducted on an in-house flow test loop per ISA S75.02.
Quality Assurance/Certification:
Master Flo Valve Inc. maintains an accredited quality program
in accordance to ISO 9001-94 and API Q1. Master Flo Valve Canada is
registered for the manufacture of choke valves and is approved to manufacture
products under license to API-6A and API-17D.
Master Flo Valve (UK) operates under Quality Management System to BS 5750
Part II / ISO 9002 accredited by Bureau Veritas.
Valve Sizes
|
Valve Model
|
Std. End Connection Sizes
|
Standard Trim
|
Maximum Pressure Rating
|
Maximum Turning Torque at 3,000
PSI
|
# Turns Close to Open
|
| Cv |
Bean Size |
PSI
|
kPa
|
ft-lb
|
Nm
|
|
P05
|
1", 2"
|
2.5
|
24
|
10,000
|
69 000
|
10
|
15
|
6
|
|
P1
|
1", 2"
|
10
|
48
|
6,000
|
41 000
|
35
|
46
|
6
|
|
P2
|
2", 3"
|
20
|
72
|
10,000
|
69 000
|
60
|
83
|
11
|
|
P25
|
2",2-1/2",3"
|
33
|
93
|
5,000
|
34 000
|
60
|
83
|
12
|
| 15,000 |
103 000 |
70 |
92 |
9 |
| 20,000 |
138 000 |
70 |
92 |
9 |
|
P3
|
3", 4"
|
50
|
116
|
6,000 |
41 000 |
45 |
62 |
17 |
| 10,000 |
69 000 |
45 |
62 |
17 |
| 15,000 |
103 000 |
70 |
92 |
13 |
|
P35
|
4", 6"
|
100
|
160
|
6,000
|
41 000
|
70
|
92
|
16
|
| 15,000 |
103 000 |
|
P4
|
4", 6"
|
160
|
198
|
6,000
|
41 000
|
96
|
130
|
20
|
| 10,000 |
69 000 |
|
P5
|
5", 6", 8"
|
250
|
240
|
6,000
|
41 000
|
81
|
110
|
22-1/2
|
| 10,000 |
69 000 |
|
P6
|
6", 8"
|
335
|
280
|
6,000
|
41 000
|
81
|
110
|
27
|
|
P8
|
8", 10"
|
700
|
450
|
6,000
|
41 000
|
96
|
130
|
33-1/2
|
Other sizes and pressure ratings are available upon
approval by Master Flo's engineering department.
Master Flo sizing is available upon request to
ensure accurate valve selection to meet your specific needs.
Request
for
Price click here