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AALBORG PNEIH.',\TI( /I( lIJI\T()I~ TYP E DP ()I ",',-'''::11' (I

INDUSTIIES

Pneumatic actuator, type dp

1 General

The pneumatic linear actuator is designed to be mounted directly on a control valve.

The pneumatic actuator converts positioning command signals into stem thrust
forces . The required back setting force is produced by the spring arrangement inside
!be actuator. The rolling-diaphragm produces linear spindle movements over !be
complete stroke.
The preferred mounting position is with !be actuator and valve spindle in vertical
position.
The mode of operation for the actuator depends on how !be springs are inserted
when !be actuator is assembled. Even when !be actuator is fitted in a piping system,
!be mode of operation can be changed.
The pneumatic actuator can be operated as:
• Spring opens valve/air closes valve operation mode
• Air opens valve/spring closes valve operation mode

Illustration of a pneumatic actuator

Operauon mode:
Spring opens. Atr clOlCl Au opens • Spnna d oleS

,
,9
Z

~~~~~~~==== ~
t::::::j::H===== ~

y - - -- - 16

::.....J:±:J! - -- - - ro
>---- 15
IT'f-- - - - f7

Figure 1 dpactuat.tif

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AALBORG PNEln.1AT I( fll TlJI\TOR TYPE DP ()I.F';~('.: '1 \
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Table I below shows a list of the position numbers in Figure I and Figure 2.

Table of position nl!ri;"e,. in Figure 1

Plrt Denom in ation Part Denomination
I Rollin. diaDhraom 15 Stroke indicator
2 OiaDhral!IJ1 housin. 16 Hex820n nut
3 OiaDbram lid 17 Mountin. rod
4 OiaDhral!IJ1 Dlate 18 Bellow
5 s,;-indle 19 Collar nut
7 SDrin. 21 O-ri n. (Stlindle
10 COU;;hORf1aDRe 22 ()"rin~ bushin~:
II Guide na. .e 26 Sioned ""ide beano.
12 Rotation truard 27 SDindle ""ide
13 Socket screw 30 Hexa20n nut
14 Threaded bushino 31 Hcxa20n nut

Table 1

1.1 Pneumatic connection

The air supply should be dry and at a low service temperature. A heat-guard should
be installed to prevent high service temperature.
The pneumatic supply tube must be connected to the diaphragm housing (2) by
operation mode "spring closes" and to the diaphragm lid (3) by operation mode
"spring opens".
By air failure the stem automatically returns into the original position caused by the
inserted springs.

Warning: The actuator diaphragm may only be pressure loaded on the side
opposite of the springs. The vent hole in the other connection must
remain open.

1.2 Assembly of the actuator on the valve

The assembling of the actuator on the valve is shown in Figure 2. For both "spring
closes" and "spring opens" operation modes the following assembling procedure
should be followed:
Step A: If the actuator and the valve are separated, press the plug and spindle unit
(5) into the closed position for operation mode "spring closes" or into the
open position for operation mode "spring opens".

Warning: Make sure that the plug does not turn while pressing on the seat
during assembly.

Step B: Loosen the socket screws (13), remove the rotation guard (12) and the guide
flange (II). The threaded bushing (14) is now free.

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AALBORG PNEU MA TIC AC fU ATOR TYPE DP m.l'i'i20:tr) 1 0
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Step C: Turn the locking hexagon nut (30) onto the valve spindle. Place the rotation
guard (12) and the guide flange (11) over the valve spindle and then turn
the threaded bushing (14) onto the valve spindle.

Step D: Check the actuator for proper operation mode and connect the pneumatic
supply to the connection piece in the diaphragm housing (2) for operation
mode "spring closes" or in the diaphragm lid (3) for operation mode "spring
opens".

Step E: Drive the actuator into approximately mid-stroke position over the air
supply and mount it onto the valve (read the value from the pressure gauge
- middle of the spring range).

Step F: Tighten the hexagon nuts (31).

Assembly of tbe actuator on tbe valve

Operation mode: Spring closes valve - Air opens valve O peration mode: Spring opens valve - Air closes valve

Pneumatic connection

1 _ _- - L~~+-_--_1 6
16
~~~~-------- 10
~~~d_------10 u..~"" - ______ 1S
15
wU'___1-9-K- _ _ _ _ 13
'-t,.....,'1---- - - 13
~~-'-~ _____ 1'
~U:!=r-~-1'
J.J1..J-......11.~~~~~___ 30 .....+-...u 11Jh-~;;r,-T_:l(---- 3D
~GD~---------1 1
- - - -- . _- - 31

Figure 2 dpactspr.tif

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AALBORG PNEUMAT IC ACTU ATOR TYPE DP OM 552011ll10
INDUSTR IES

1.3 Adjustment of the starting pressure signal

Step A: Drive the actuator to the required spring-starting point over the air supply.

Step B: Turn the threaded bushing (14) up against the coupling flange (10) so that
the collar enters into the flange and presses against it. Make sure that the
plug is lying on the valve seat.

Attention: Note tbat sufficient tbread of tbe valve spindle is inside tbe tbreaded
busbing (14). If not, turn the coupling flange (10) downwards from
tbe actuator spindle and pull the threaded bushing (14) against it.

Step C: For operation mode: "spring closes":

Attach the guide flange (II) and the rotation guard (12) with the socket screws
(13) to the coupling flange (10).
Check that the plug lifts off the seat at the required spring starting point.
Step D: For operation mode: "spring opens":

Check that the plug leaves the end position at the required spring starting point,
and fini shes the valve stroke at the spring-range end value.
The plug must then also press on the valve seat.
Step E: After the test operation set the stroke indicators (15) into the end positions.

Step F: Lock the hexagon nuts (16 + 30) at the valve mid-stroke.

Step G: Do not turn the plug on the seat when it is under force.

2 Reversal of the actuator action

The actuator action can .be reversed even when the valve is installed in a piping
system . The position numbers mentioned in this section refer to Figure I and Figure
2.
Step A: Drive the actuator into approximately mid-stroke position with the air
supply.

Step B: Loosen and remove the socket screws (13) from the coupling flange (10)
and drop the rotation guard (12) over the va lve spindle.

Step C: Remove the hexagon nuts (31) from the actuator and lift off the valve.

Step D: Reduce the air supply until the chamber is pressure free.

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AALBORG PNEU MAT IC AC T UA TO R T YPE DP OM55201101 0
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Step E: Loosen and remove the diaphragm lid screws.

Step F: Remove the diaphragm lid (3).

Warning: The actuators DP 32 and DP 33 have two longer screws when fitted
with stronger spring ranges. The actuator DP 34 has four. These
screws should be the last screws to be loosened, and must be
loosened evenly to reduce the high spring tension.

Step G : For reversal from "spring closes" into "spring opens":

- Remove the springs (7) and the diaphragm plate (4) with the diaphragm (1) and
the spindle (5).
Loosen and remove the seal lock nut ( 19) and remove the spindle (5). Turn over
the diaphragm plate (4) with the diaphragm (1) and the diaphragm clamping
flange, and place it over the spindle (5).
- Tighten with the seal lock nut (1 9). Make sure that the spindle surface is not
damaged .
Grease the spindle surface and the O-ring.
Place the diaphragm plate (4) with the diaphragm ( I) into the diaphragm lid (3).
Arrange the springs (7) onto the moulds pressed into the diaphragm plate (4).
Place the diaphragm housing with the spindle sealing unit over the spindle, and
screw it together. Make sure that the springs stay properly arranged.
- Turn the hexagon nut ( 16) and the coupling flange (10) onto the spindle (5).
- Mount the actuator as described previously, and connect the air supply tube to
the diaphragm lid (3).

Step H : For reversal from "spring opens" into " spring closes":

- Remove the diaphragm (I) and the diaphragm plate (4) with the spindle (5) and
the springs (7).
- Loosen and remove the seal lock nut (19) from the spindle (5). Tum over the
diaphragm plate (4) with the diaphragm (I) and the diaphragm clamping flange,
and place it on the spindle (5).
- Tighten with the seal lock nut (19). Make sure that the spindle surface is not
damaged.
- Grease the spindle surface and the O-ring.
- Stick the diaphragm plate (4) with the diaphragm (I) and the spindle (5) into the
diaphragm housing (2).
- Arrange the springs (7) onto the moulds pressed into the diaphragm plate (4) .

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AALBORG PNEUM ATIC ACTUATOR TYPE DP OM5 5201101 0
INDUSTRIES

Place the diaphragm lid (3) on the top, and screw it together. Make sure that the
springs (7) stay properly arranged.
Turn the hexagon nut (16) and the coupling fl ange (10) onto the spindle (5).
Mount the actuator as described previously, and connect the air supply tube to
the diaphragm housing (2).

3 Manual operation device

Some actuators are fitted with a manual operation device. The device is connected to
the actuator by means of a new diaphragm lid, a spindle extension with a US IT-ring
and a spindle sealing unit.
The manual operation device is equipped with stroke indicators. The stroke
indicators of both the actuator and the manual operation device must be in the same
end positions when the actuator is pressure free.
The manual operation device must be set into neutral position when the actuator is
running automatically.
The locking device of the manual operation device must be unlocked before
operating.
The locking device prevents an unwanted disarrangement of the setting during
operation, e.g. due to vibration, etc.

4 Maintenance
The pneumatic actuator is maintenance free . To maintain a disturbance free
operation, the air should be supplied by an air-supply stat ion.
The diaphragm, spindle sealing unit and springs are wear parts and should be
replaced when necessary.

4.1 Exchange of spindle sealing

When the spindle sealing is changed, the slotted PTFE-guide bearing and the O-ring
should be replaced. The spindle surface must be clean and undamaged . Before the
actuator is assembled, the spindle unit and the spindle must be greased .

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