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PMV P3
User Manual
24 pgs2.27 Mb0

Flowserve PMV P3 User Manual

P3/EP3 Modular Linear Positioner
Installation
Operation
Maintenance
2
Contents
1. Introduction ................................................................................................................... 3
Safety instruction ............................................................................................................... 3
2. Storage ............................................................................................................................ 4
Storage outdoors or for a longer period ............................................................................. 4
Storage in a warm place .................................................................................................... 4
4. Variants ........................................................................................................................... 6
Optional equipment ........................................................................................................... 6
5. Function .......................................................................................................................... 7
Increase in signal pressure ................................................................................................. 7
Decrease in signal pressure ............................................................................................... 7
6. Installation...................................................................................................................... 8
Air supply requirements .................................................................................................... 8
Mounting ........................................................................................................................... 9
Connections ..................................................................................................................... 11
Direct / Reverse function ................................................................................................. 11
Single acting positioner ................................................................................................... 12
Electrical connections ...................................................................................................... 13
Control drawing ...............................................................................................................14
7. Adjustments..................................................................................................................15
Gain ................................................................................................................................. 15
Default settings ................................................................................................................ 15
Setting the zero position and span ................................................................................... 15
8. Maintenance/service .................................................................................................... 16
Valve block ...................................................................................................................... 16
Flapper nozzle ................................................................................................................. 17
Gain screw ....................................................................................................................... 17
Integral I/P converter ....................................................................................................... 17
Feedback arm / Spindle ................................................................................................... 18
9. Trouble shooting .......................................................................................................... 19
10. Technical data ............................................................................................................ 20
11. Spare Parts List .......................................................................................................... 22
1. Introduction
The PMV P3 is a modular Positioner sys­tem designed for use on control valves with linear motion. The basic unit is the P3 posi­tioner, which is available for single acting. The I/P converter can be integral, located in a separate mounted module (Ex), or located elsewhere. The P3 can be equipped with connection blocks for pressure gauges to indicate:
- actuator pressure
- air supply pressure
- input signal pressure
3
Safety instruction
Read the safety instructions in this manual carefully before using the product. The installation, operation, and maintenance of the product must be done by staff with the necessary training and experience.
PMV P3 basic unit
PMV P3 with explosion proof I/P
4
2. Storage
General
The PMV positioner is a precision in­strument. Therefore it is essential that it is handled and stored in the correct way. Always follow the instructions below!
N.B. As soon as the positioner is connected and started, an internal air bleed will provide protection against corrosion and prevent the ingress of moisture. For this reason, the air supply should always be kept on.
Storage indoors
Store the positioner in its original packaging. The storage environment must be clean, dry and cool, (15 to 26°C, 59 to 79°F).
Storage outdoors or for a longer period
If the positioner must be stored
outdoors, it is important that all the cover screws are tightened and that all connections are properly sealed. The unit should be packed with a desiccant in a plastic bag or similar, covered with plastic, and not exposed to sunlight, rain, or snow.
This is also applicable for long-term storage (more than 1 month) and for long transport by sea.
Storage in a warm place
When a positioner is stored in a warm place with a high relative humidity and is subjected to daily temperature variations, the air inside the unit will expand and contract.
This means that air from outside the unit may be drawn into the positioner. Depending on the temperature variations, relative humidity, and other factors, condensation and corrosion can occur inside the unit, which in turn can give rise to functional disorders or a failure.
3. Design
5
The P3 positioner comprises a basic module with a single acting valve block. It also includes a sealed chamber with termin­als for the electrical input signals.
The I/P unit can be built into the main housing (as shown in the figure below) or
I/P converter
Feedback arm
Feedback spring
located externally (explosion proof), see section ”Variants”.
The adjusting screws and knobs are accessible under the removable sealed alu­minium cover.
Balance arm
Flapper nozzle
C+
➠
➠
Supply
Input 3-15 psi
Electrical connection
Figure shows P3 positioner with integral I/P converter and cover removed
Zero position adjustment
Adjusting screw, damping
Span adjustment
Adjusting screw, gain
6
4. Variants
Standard designs
P3/EP3 is available single acting.
I/P converter can be integral or located
elsewhere.
P3
Pneumatic, single acting, to be
connected to an external I/P converter.
EP3, EP3IS
Electro-pneumatic, single , with integral I/P converter. Intrinsically safe model also available.
EP3EX
Explosion proof model, I/P converter located in separate, sealed enclosure.
Optional equipment
P3 / EP3 positioner can be equipped with connection blocks and pressure gauges for:
- input signal pressure
- input air supply pressure
- output pressure
P3/EP3
EP3 EX
5. Function
General
The P3 positioner operates on the force balance principle. Changes are initiated by the
signal pressure from the I/P converter. The functionality is described briefly below.
Single action
7
Feedback arm
Plug
Signal pressure
Signal diaphragm Balance arm Flapper nozzle
Increase in signal pressure
When the air pressure on the signal diaphragm increases, the balance arm is pres­sed down and the flapper nozzle closes. The pressure on the relay diaphragm then increases and the plug valve opens.
Air is now supplied to the actuator, the spindle movement rotates the feedback arm, the balance arm is lifted, and the flapper nozzle opens. The pressure on the relay diaphragm is reduced and the plug valve reduces the air flow to the actuator. An equilibrium position is thus reached and the valve being controlled is in the desired posi­tion.
valve
Decrease in signal pressure
diaphragm is reduced, the balance arm is lifted and the flapper nozzle opens. The pressure on the relay diaphragm is then reduced and the plug valve upper seal opens and vents.
and its spindle moves. The actuator movement goes back through the arm mechanism (see figure) to the positioner spindle, which rotates the feedback arm. The balance arm is now lowered by the reduced spring force and closes the flapper valve. An equilibrium position is thus reached and the valve being controlled is in the desired posi­tion.
Relay diaphragm
Venting
When the air pressure on the signal
Air is now ventilated from the actuator
To/from actuator
Air supply
8
6. Installation
Air supply requirements
Max. air supply pressure, see the section Technical Data on page 20.
The supply air must be free from moisture, water, oil, and particles.
The supply air must be dried or be treated in such a way that its dew point is at least 10°C (18°F) below the lowest expected ambient temperature.
Before the air supply is connected to the positioner, we recommend the hose is opened freely for 2 to 3 minutes to allow any con­tamination to be blown out. Direct the air jet into a large paper bag to trap any water, oil, or other foreign materials. If this indicates
that the air system is contaminated, it should be properly cleaned.
To ensure a stable and problem-free ope-
ration, we recommend the installation of a filter/pressure regulator <40µ as close to the positioner as possible.
WARNING. Do not direct the open air jet towards people or objects because it may cause personal injury or damage.
Poor air quality is the main source of
problems in pneumatic systems.
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